utilization of paddy straw as fuel in brick kilns

Final Report

Utilization of Paddy Straw as Fuel in Brick Kilns

November 2015

Prepared by: Punjab State Council for Science & Technology

MGSIPA Complex, Sector 26, Chandigarh-160019 www.pscst.gov.in

Submitted to :

Punjab Pollution Control Board Vatavaran Bhawan, Nabha Road, Patiala-147001

www.ppcb.gov.in

PROJECT TEAM

Punjab State Council for Science & Technology, Chandigarh

• Sh. S.K. Jain,

Additional Director

• Sh. Pritpal Singh, Senior Engineer / Certified Energy Auditor

• Sh. Maganbir Singh, Process Engineer/ Certified Energy Auditor

• Sh. Amit Kumar, Assistant Engineer / Certified Energy Auditor

• Ms. Rajeena, Steno Typist

CONTENTS S. No. Description Page No.

Executive Summary i-iii 1.0 Introduction 1 2.0 Pre Demonstration Activities 3

2.1 Identification of Project Area 3 2.2 Availability of Paddy Straw 3 2.3 Visit to Biomass Power Plants 4

2.4 Interaction with Experts 5 2.5 Selection of Kilns 5 2.6 Identification of Briquette Manufacturer 6

3.0 Production of Briquette for R&D Studies 9 3.1 Procurement of Chopped/ Pulverized Paddy Straw 10

3.2 Briquetting of Paddy Straw & Biomass 11 4.0 Phase-I: Combustion Studies in Brick Kilns (Pilot Trials) 13 5.0 Pilot Trials: Baseline Studies 15

5.1 Baseline Studies of FCBTK- Using Biomass 16 5.2 Energy Performance & Specific Energy Consumption – Baseline 20

6.0 Pilot Scale Studies Using Briquettes 23 6.1 Pilot Trial-I: M/s. J.O. & Co., Fazilka 23

6.1.1 Outcome of Pilot Trial-I 28 6.2 Pilot Trial- II: M/s. S.S. Bricks, Muktsar 29

6.2.1 Outcome of Pilot Trial-II 33 6.3 Pilot Trial-III: M/s. J.O. & Co., Fazilka 33

6.3.1 Outcome of Pilot Trial-III 35

7.0 Summary of Pilot Trials 37 8.0 Phase-II: Full Scale Trials 41

8.1 Selection/ Identification of Kilns 41 8.2 Identification of Briquette Manufacturer 42 8.3 R&D Efforts for Improving Briquette Manufacturing Process 42 8.4 Briquette Manufacturing for Full Scale Trials 43

9.0 Combustion Studies in Brick Kiln (Full Scale Trials) 45 9.1 Full Scale Trial-I: M/s. Burj Hakima Gram Udyog Samiti, Raikot 46

9.1.1 Output Quality of Fired Bricks 50 9.2 Full Scale Trial-II: M/s. AS Bricks Industries, Moga 51

9.2.1 Output Quality of Fired Bricks 53

10.0 Summary of Full Scale Trials 55 10.1 Impact on Environment 55 10.2 Cost of Paddy Straw briquetting 56 10.3 Economic viability of Paddy Straw briquetting 56

11.0 Best Operating Practices during use of briquettes as Fuel 58 12.0 Inferences 58 13.0 Way Forward 61

Report on Utilization of Paddy Straw as Fuel in Brick Kilns

Punjab State Council for Science & Technology P a g e | 1

1.0 Introduction

Punjab is an agricultural State and considered as food bowl of India. It is one of the leading producers of the most consumed crops like wheat & rice. These crops besides giving food grain, produces large amount of agro-waste. The agro-waste from wheat i.e. wheat straw is almost consumed, as it is mainly being used as animal fodder whereas the rice straw having low nutritional value, is not used as fodder. Further due to its inherent properties, it does not find much usage in industrial sector.

The total land area under paddy cultivation in Punjab is 2.82 million hectare. Annual paddy production is 10.54 million MT and 17-18 million MT paddy straw is generated. Out of the total paddy straw generated, 85-90% is burnt in fields thus releasing Green House Gases/ dust particles in the environment. The issue of paddy straw burning is a national/ global problem.

Presently, on an average, only 10-15% paddy straw is being used along with other biomass as fuel by biomass based power plants. While using paddy straw as fuel, these power plants are facing operational problems due to the presence of potassium and chlorides in the paddy straw. Moreover, the collection & transportation of biomass is another issue.

The burning of paddy straw is one of the major environmental issue/concern for the State and the Government has formulated a draft policy for Management and Utilization of paddy straw in which utilization of biomass-paddy straw briquettes in brick kiln is one of the options.

Punjab State Council for Science & Technology (PSCST) submitted R&D proposal to establish the use of paddy straw as fuel in brick kilns to Punjab Pollution Control Board (PPCB) for funding with the scope of work as under:

1. Meeting with stakeholders/leading brick entrepreneurs for their suggestions & short listing of entrepreneur for R&D activities.

2. Tie up with briquette manufacturers to supply specific quantity of briquettes with varying percentage of paddy straw and biomass.

3. Analysis of fuel to be used. 4. Pilot studies on combustion behaviour and quality of output (bricks) by:

a. Feeding and firing of briquettes in limited section of brick setting for 3-4 days in 3 brick kilns (to be carried out using combination of briquettes containing varying ratio of paddy straw and biomass).



b. Study of additional coal/other biomass supplementation which would depend upon the characteristics of the fuel.

5. To finalize the protocol for feeding, firing practices in brick kiln based on the outcome of pilot study.

6. Full scale trial for 2-3 days in two brick kilns using most optimal ratio. 7. Preparation of final report and sharing of study outcome.

PPCB in principle approved the project in January 2014 and formally approved vide their office order no. SEE(HQ-I)/PPCB/2014/39 dated 13.02.2014. The detailed report is given in the following chapters.



2.0 Pre Demonstration Activities

2.1 Identification of Project Area The methodology/ operating practices using biomass viz a viz fossil fuel (coal etc.) as fuel are entirely different. This is due to the fact that the biomass mainly contains high volatiles (60 to 70%) whereas, the percentage of volatile carbon in fossil fuel ranges between 15% to 40%. During initial survey, it was observed that around 600 brick kilns in the Southern Punjab (adjoining Rajasthan & Haryana) use either 100% loose biomass or biomass in combination with coal as fuel & adopt unscientific ways of fuel feeding. A variety of biomass such as mustard straw/ heena straw/ guar husk/ cotton stalks/ peanut straw etc. is used as fuel which is mainly being purchased from Rajasthan. The feeding and operating practices adopted in biomass fired kilns are different from the kilns using coal as fuel. In the remaining parts of the State, most of the kilns use coal as fuel. A few brick kilns have been reported to be using press mud/ saw dust briquettes in limited quantity alongwith coal as fuel.

Under the proposed project, the combustion behavior of briquettes containing paddy straw as one of the constituents alongwith other biomass was to be studied on pilot scale to assess the feasibility of use of paddy straw as fuel in brick kilns. Since, the brick kilns operators in South Punjab had the first hand experience of using the biomass (except paddy straw) as fuel, the district of Muktsar, Bathinda and Fazilka were selected as project area for conducting pilot trials.

2.2 Availability of Paddy Straw

Six biomass based power plants are functional in different parts of the State wherein paddy straw is also being used as fuel. Over the years, a mechanism has been set up adjoining these biomass based power plants for collection of paddy straw. Even Self Help Groups (SHGs) have also been formed by leading farmers at many places for collection of paddy straw. These SHGs supply paddy straw bales to the power plants and other end users. Leads for assessing the availability of paddy straw from the suppliers

Biomass fired kiln

Coal fired kiln



were then taken from various sources including biomass power plants & PPCB Regional Offices. Three paddy straw suppliers were identified at Machhiwara (Ludhiana), Boha (Mansa) & Fazilka. The samples of paddy straw were collected and sent to the lab for ascertaining its calorific value and other parameters. Results are tabulated below:

Table-2.1: Analysis of Paddy Straw Samples Parameter Vill. Machhiwara,

Distt Ludhiana Village Udat

Saidawala, Mansa Vill. Painchanwali,

Fazilka Moisture % 14.78 13.42 6.28

Ash % 25.09 11.96 20.93 Volatile Matter% 57.43 71.56 63.18 Fixed Carbon % 13.13 14.63 14.48 GCV in kcal/kg

(as received)2764 3392 3386

Remarks Paddy straw was rotten

Paddy straw of last season.

Paddy straw of last season

Out of above three paddy straw suppliers M/s. Sampurn Agri Ventures (Pvt.) Ltd., Vill. Painchanwali, Fazilka was shortlisted in consultation with PPCB- as it falls in the project area.

2.3 Visits to Biomass Power Plants The following biomass power plants were visited to assess the performance of chopping/grinding machines for paddy straw & combustion behavior of paddy straw as fuel in operational power plants:

• M/s Punjab Biomass Power Pvt. Ltd., Ghanaur (Patiala) • M/s Universal Biomass Energy Pvt. Ltd., Channo (Muktsar) • M/s Dee Development Engineers Ltd., Gadda Doab, (Fazilka)

a) The power plant at Channo was using upto 30% of paddy straw. The paddy straw was being fed in bales & no chopping of paddy straw was being done. The management was apprehensive about the cost involved in the chopping of paddy straw. Large sized clinkers were observed in the ash coming out of the boiler. It was informed that temperature in boiler furnace was not generally raised above 7500C so as to contain the clinker formation.

b) The power plant at Ghanour was using paddy straw as main fuel alongwith sugarcane leaves. Around 300-350 Tons of paddy straw is reported to be used every day. The paddy straw is being fed into the boiler in bales as well as in



chopped form. Five biomass choppers were installed in the premises of the plant and two choppers were in operation at the time of visit.

c) The power plant at Gadda Doab had installed biomass choppers and was using paddy straw in chopped form as well as in bales.

In general, these biomass based power plants were operating at a low PLF due to limitation of firing temperature because of presence of potassium, chlorides and high silica content in paddy straw. The choppers being used by biomass based power plants were mainly supplied by M/s. Lehra Fuel Tech Pvt. Ltd., Mandi Ahmedgarh and M/s. Swastik Industries, Yamunanagar. The industries have informed that these choppers require frequent maintenance even for chopping the paddy straw upto 3 inch size due to high wear and tear of chopping blades.

2.4 Interaction with Experts

The use of paddy straw along with other biomass was discussed with experts from School of energy, PAU, Ludhiana; Central University, Bathinda; National Institute of Renewable Energy (NIRE), Kapurthala and others. The experts were of the view that briquettes consisting of paddy straw and other biomass mix be tried in limited section of brick kilns first. All were of the view that the trial should be started with 10-15% paddy straw and based on the combustion behaviour of briquette, the ratio of paddy straw be increased accordingly. They were of firm opinion that paddy straw alone would not perform efficiently.

2.5 Selection of Kilns

Discussions were held with leading kiln owners, President of Punjab Brick Kiln Owners Association (BKOA) & District President of project area for the selection of kiln for the R&D activity. The kiln owners & BKOA appreciated the PSCST initiative and committed to provide biomass for mixing with paddy straw.

The Brick Manufacturers in Mukatsar, Fazilka and Abohar were contacted to identify progressive kiln owners willing to participate in R&D activities. During the visit of PSCST team to Muktsar/ Fazilka area on 21st-22nd January 2014, following kiln owners agreed to collaborate with Council and offered their kiln for R&D studies. The selected kiln owners were open to the R&D ideas, upfront & ready to participate in the R&D activity. The benefit of using biomass briquettes was discussed with the kiln owners and their firemen. Moreover, their master firemen agreed that quality of brick will improve in case they use biomass briquettes.



Table-2.2: List of Identified Kilns Name of Kiln Daily Production Capacity Fuel Presently

being used M/s. S.S. Bricks, Muktsar 30-40,000 bricks Biomass* & Coal

M/s. JO & Company, Fazilka 35-40,000 bricks Biomass*

M/s. Miglani Brick Kiln, Jalalabad, Distt. Fazilka

30,000 bricks Biomass*

* Except paddy straw

These kilns are using biomass with/without coal as fuel and the biomass is being fed in loose form.

2.6 Identification of Briquette Manufacturer

Although, briquetting is being done at many places in Kotkapura, Fazilka, Abohar, Amritsar etc. mainly using saw dust or press mud from sugar mills of the adjoining area, no briquette manufacturer has ever produced briquettes from paddy straw on commercial scale. Whereas the briquette manufacturers in Ganganagar, Hanumangarh & Sangriya (Rajasthan) are supplying briquettes from low density biomass such as mustard straw, guar, cotton stalk briquettes to number of industrial units in the states of Punjab, Haryana and Himachal Pradesh. Paddy straws being low density biomass, briquette manufacturers in Rajasthan were shortlisted. Discussions with the briquette manufacturers revealed that keeping the brick setting of kiln in view, briquette of size 50 to 65mm dia. would be the most suitable for its use in brick kilns.

Further, discussions with briquette manufacturers revealed that the biomass including paddy straw needs to be chopped/grinded for briquette making. Since the stem of paddy straw is thin and has low bulk density, its chopping is difficult. Discussions with machinery suppliers revealed that chopping of paddy straw requires high speed cutters. The prevalent cost of choppers with a capacity of 1.5 to 3 ton/hr, requiring 50-75 hp motor is Rs. 10-12 lacs.

The briquette manufacturers informed that they do not have requisite cutting machines/choppers and in case chopped paddy straw is made available, they can produce briquettes. Further, as it was a trial activity, no vendor was willing to invest in the paddy straw cutting/ chopping machine.

However, M/s. Lehra Fuel Tech Pvt. Ltd., a leading machine manufacturer at Ahmedgarh Mandi, who claims to provide complete briquetting machine with improved metallurgy suitable for paddy straw, could not produce briquettes with 100% paddy straw and subsequently he demonstrated the trial briquettes from paddy straw and saw dust mix in the ratio 70:30 in a limited quantity only.



After discussions with PPCB, the following briquette manufacturers were identified in Fazilka district and Hanumangarh / Sri Ganganagar district of Rajasthan (along the Punjab border) :

1. M/s. Kushal Suri Industry, Village Rampur, Fazilka 2. M/s. Gujrat Agro Fuel, Village Ghalu, Opp. Sugar Mill, Fazilka, 3. M/s. Punjab Fuels, Plot No. E295, RIICO, Shri Ganga Nagar 4. M/s. Satyam Agro Fuel Industry, Plot No. F127, Phase-II, RIICO, Hanumangarh 5. M/s. Shri Balaji Bio Coal Industries, Plot No. 33A-34, Udyog Vihar, Sadul

Shahar 6. M/s Shree Krishna Agro Fuels, Sangriya

Sample briquettes were prepared at briquette manufacturing units at Sr. No.1,3,4,5 & 6 to study the feasibility of preparing briquettes of paddy straw mixed with other biomass in different ratios and assess the manufacturing capability of the unit. A few photographs of pilot studies are given below:

Paddy straw & biomass mixing at briquetting plant M/s Shree Krishna Agro Fuels, Sangriya

Briquetting Trials at M/s. Punjab Fuels, Sri Ganga Nagar



Preparing sample briquettes at M/s. Shri Balaji Industries, Sadul Shahar

During trial, paddy straw & biomass were mixed in different ratios and briquette samples were prepared and following observations were made:

• The hourly production of briquettes decreased due to low bulk density and presence of silica in the paddy straw.

• Labour working in briquette manufacturing unit offered resistance as they were employed on job basis. Reduction in production would affect their financial returns.

Three briquette manufacturing units i.e. sr. no. 3, 4 &5 expressed their inability to do briquetting as per the R&D requirement due to prior commitments. Further, M/s. Kushal Suri Industries, Fazilka could not produce briquettes with the existing old machinery.

The briquettes produced during the trials at M/s Shree Krishna Agro, Sangriya were of good quality and the industry consented to manufacture briquettes on the condition that grinded/ chopped paddy straw would be made available at site as the industry had no provision for grinding of paddy straw.



3.0 Production of Briquette for R&D Studies

Activities involved in manufacturing of briquettes were identified as: • Procurement of paddy straw and biomass • Grinding of paddy straw as no briquette manufacturers have grinding/chopping

facility. • Preparation of briquettes containing paddy straw and biomass in different ratios

(i.e. 15:85, 30:70 & 50:50). • Firing of bricks using mix of biomass and paddy straw briquettes.

The process of converting biomass and paddy straw mix into briquettes involves the following steps:

The process description of each step is discussed below:

Paddy Straw Procurement

Chopping/ Pulverizing

Extrusion in briquetting press

Biomass and cow dung as per requirement

Transportation to Briquetting Unit

Mixing of Paddy Straw & Biomass

Collection and transportation to

kiln site



3.1 Procurement of Chopped/Pulverized Paddy Straw

Chopping/ grinding of paddy straw upto 3-8 mm size is the only critical issue in the absence of appropriate grinder/ choppers with the briquette manufacturers. The pulverizing facilities were available with M/s. Sampurn Agri Ventures (P) Ltd., Fazilka who agreed to supply the pulverized paddy straw during the pilot trials and full scale studies.

Pulverizing of paddy straw

The pulverized paddy straw becomes bulky and was transported on a specially modified tractor trolley to the briquetting plant and briquettes were then transported to the kilns where trials were being conducted.



3.2 Briquetting of Paddy Straw & Biomass

M/s Shree Krishna Agro Fuels, Sangriya (Rajasthan) was shortlisted for briquette manufacturing as per R&D requirements. Three ratios of paddy straw & mustard straw were got prepared (paddy Straw: Mustard Straw in the ratios of 15: 85, 30:70 & 50:50). For better compaction of the briquettes 3-5% dried cow dung was added, depending on percentage of paddy straw in the mix. However, the briquette machinery manufacturers were of the view that by proper compaction/hydraulic pressure, briquettes could be manufactured even without the use of cow dung.

The briquettes were manufactured under 24 hour surveillance of PSCST team so as to maintain proper mix ratios & restrict addition of cow dung for increasing the production rate.

Following observations were made during the briquetting operations: • The output of the briquetting machine decreased with higher %age of paddy

straw. • The pulverized paddy straw, being lighter in weight becomes airborne during its

mixing with mustard straw and the workers offered resistance for producing briquettes as per R&D requirement.

• The workers engaged by the briquette manufacturers are on contract and their wages are paid on production basis. Therefore, the foreman and workers operating the machine showed resentment as the production capacity decreased on addition of paddy straw.

The representative samples of raw materials and briquettes were collected and were got tested for various parameters. The results are given below in Table-3.1.

Table-3.1: Proximate analysis of biomass/briquettes

Parameters

Paddy straw

Mustard Straw

Cow dung

Briquettes (with paddy straw & biomass in the ratio)

15:85 30:70 50:50 Moisture % 6.28 6.08 7.71 7.88 6.88 7.34 Ash % 20.93 5.75 34.36 13.04 22.45 23.43 Volatile matter% (dry basis)

63.18 76.89 50.02 69.41 61.06 60.09

Fixed Carbon % 14.48 16.98 12.75 16.43 14.83 14.62

GCV in kcal/kg 3386 3985 2831 3566 3274 3155



Preparation of paddy straw & biomass mix

Briquetting of paddy straw & biomass

Paddy straw & biomass briquetting Briquette samples with paddy straw & biomass in different ratios

Segregation of briquettes different ratios Transportation of briquettes to kiln site



4.0 Phase-I: Combustion Studies in Brick Kiln (Pilot Trials)

Enquiries with Brick Associations revealed that paddy straw has never been experimented as fuel in the brick kilns. Therefore, pilot studies were planned to be conducted in limited section of brick settings in a kiln for 3-4 days. Salient features of the studies carried out during the last working season were as under:

• During the pilot trial, briquettes containing varying ratios of paddy straw and biomass (15:85, 30:70 & 50:50) were used.

• Additional requirement of coal/biomass supplementation was also assessed during the field study.

• The complete log of combustion behavior of paddy straw and other fuel supplementation including quantity and frequency of fuel feeding, non-charging period and flue gas analysis was recorded and maintained.

• The feedback and response of workers i.e. firemen & brick unloaders, during the use of briquettes were also assessed.

• The quality of brick was assessed during withdrawal time and the data was co-related with the combustion practices adopted during the firing of that particular row of brick setting.

The baseline & pilot studies were carried out in these kilns during the period mentioned in table below:

Table-4.1: Details of pilot trials conducted during the last working season Pilot Trial

Period of Trials Name of Kiln Fuel used No of Lines/ Approx.

bricks fired

I

17.04.14 to 18.04.14 (baseline studies)

M/s J.O. Co.,Vill. Ladhuka, Fazilka

Loose biomass 10 lines/ 0.38lacs

05.05.14 to 09.05.14

Briquettes (Paddy Straw/ other Biomass

in the ratio 15:85; 30:70 &50:50

34 lines/ 1.29 lacs

II 10.05.14 (baseline studies)

M/s S.S. Bricks, Muktsar

Loose biomass & coal

5 lines/0.20 lacs

28.05.14 to 31.05.14

Briquettes (Paddy Straw/ other Biomass in the ratio 15:85 &

30:70

23 lines/ 0.92 lacs

III 01.06.14 to 03.06.14

M/s J.O. Co.,Vill. Ladhuka, Fazilka

Briquettes (Paddy Straw/ other Biomass

in the ratio 30:70 &50:50

19 lines/ 0.72 lacs



Before conducting the pilot studies, existing feeding, firing and operating practices of the same kiln were studied so as to generate baseline data. The Specific Energy Consumption (SEC) was also calculated. The additional information/ data pertaining to the output quality of bricks with existing practices was also collected. While conducting the above studies, pre and post energy audit was carried out which included the following parameters:

• Flue gas analysis (CO, CO2, O2, Temp., Excess Air) • Temperature monitoring in the pre-heating, cooling and firing zone. • Temperature profile of fired bricks • Quantity & frequency of fuel feeding and firing practices • Leakages/heat loss from various components such as top of brick

setting, heat loss from feedhole cover and wicket wall etc. • Quality of fired bricks

Detail of studies carried out during these trials is given in the subsequent chapter-5.



5.0 Pilot Trials: Baseline Studies

The use of biomass except paddy straw as fuel in brick kilns is very popular in the States of Haryana and Rajasthan since long. Whereas during the last 5-6 years, the brick kiln owners in the southern district of Punjab have also started using these biomass in place of coal. The reason for shift from coal to biomass is the rising prices of coal and abundant availability of biomass at much cheaper rates.

The fuel feeding, firing and operating practices in coal fired brick kilns and biomass fired brick kilns is entirely different. Over the years the workers engaged in biomass based brick kilns have developed partial skills in use of loose biomass as fuel. A comparison of practices/ salient features adopted in coal based FCBTKs and biomass based FCBTKs is as under:

Table-5.1: Salient practices adopted in Coal fired and Biomass fired BTKs Parameters Coal Fired BTK Biomass fired BTK

Fuel feeding mechanism

• Fuel feeding done using 0.75 to 2.50 kg spoon.

• Two men feeding is done

• Feeding done with tokries / palli weighing 35-40 kg.

• Two men feeding is done Feeding quantity • 2-6 spoons per feedhole in

one feeding cycle. • 2-3 lines are fired

simultaneously. • Fuel feeding done for 10-15

min. followed by non feeding cycle of 20-45 min.

• Min. 1-1.5 palli is fed in one hole at one time

• Biomass feeding in one line only.

• Feeding done for 25-40 min. followed by non feeding period of 45-55 min.

Zone length Combustion zone 3-6 feet 2 feet

Preheating zone 55-70 feet 100-120 feet Cooling zone 150-170 feet 250-290 feet

Feed holes size 4”x4” 5”x5” Feed hole cover size 9” 10-11” Brick quality • The upper 2-3 layers are

generally under-burnt/ 2nd class.

• The brick quality differs from Layer to Layer.

Other Observations • High surface temperature in firing zone. Very high %age of carbon in flue gas

• High fugitive emissions due to self ignition of biomass at the kiln surface



A variety of biomass such as cotton stalks, mustard stalks and guar, depending upon its availability are being used. Biomass is generally fed into single row of brick settings in a very unconventional and unscientific way.

A heap of fuel is dumped over the feed holes to be opened and feeding of fuel is started into the feeding holes using wooden shovel/steel rods. Fugitive emissions are generated at the surface itself due to the self ignition of biomass and hence lot of heat value is lost resulting in high temperature ranging between 100-220oC on kiln surface & 450-550 oC on feedhole covers. In biomass fired brick kilns, the brick setting is slightly different from coal fired brick kilns. Biomass is fed continuously for 25-40 minutes every 70-95 minutes. The percent output of first quality bricks in case of biomass fired brick kilns is generally less than coal fired brick kilns. Also biomass fired bricks have wide variation in colour ranging from yellowish red to light red. The upper layers of brick settings produce good quality bricks whereas the bottom 2-3 layers remain poorly fired/ under-burnt. To overcome this problem, a few brick kilns have been using coal after completing the biomass feeding cycle. Pilot scale trials were carried out in two kilns using briquettes and biomass. The general description of these kilns is given below in Table-5.2.

Table-5.2: Description of FCBTKs using Biomass as fuel Kiln ID

Location Fazilka Muktsar Production Daily (No.) 40,000 approx. 40,000 approx. Firing temperature 980-10800C 960-10500C Product quality Color of the brick is

yellowish Medium to low ringing

sound

Color of the brick is yellowish

Medium to low ringing sound

Salient features of kiln Kiln Capacity/ Circuit (million) 1.1 1.3

No of Columns (ghori) 25 27 No of Brick Settings

(raddas) 23 22

Trench width 28’ 6’’ 32’ 6” 5.1 Baseline Studies of FCBTK-Using Biomass

Detailed audit of the two shortlisted kilns was carried out with existing practices for establishing baseline studies. During the audit, existing operating practices and fuel used were not altered. The fuel feeding and operating practices adopted in these kilns and their energy performance is given in the Table-5.3 & Table-5.4.



Table-5.3: Conventional Fuel Feeding and Operating Practices Kiln Name Description of Operating PracticesJO Brick Kiln

• Biomass (such as mustard straw, guar, cotton sticks etc.) feeding done in one line only consisting of 13 feed holes

• Two man firing in one line • Heavy biomass feeding with vehngis / tokris of capacity 35-

40 kg is done for 25-30 minutes followed by non charging cycle of 35-40 minutes.

• Line is closed after 2-2.5 hrs and new line is inducted. • High surface emission due to self ignition of fuel as it is

dumped over feed hole covers with temperature of 450-500°C

• On an average 10-12 line fired daily. • The keri / rappish thickness over the kiln surface was 3-5

inch SS Bricks

• Fuel feeding done in one line only consisting of 14 feed holes

• Fuel used: coal (15%), biomass (mustard straw/ guar husk) (85%)

• Fuel feeding is done by two firemen • The newly opened line fed with coal. • Coal feeding done with spoon of capacity 1.5 kg and 4-6

spoons are fed in one hole in each feeding cycle • Only one feeding cycle with coal is followed by non

charging period of 15-20 minutes which is followed by heavy biomass feeding for 35-40 minutes followed by non feeding period of 45-55 minutes

• Biomass feeding is done with tokris weighing 27 kg (average)

• High surface emissions during biomass feeding due to self ignition of biomass on kiln surface

• On an average 10 lines are fired per day



Loose biomass feeding – Conventional Method

Combustion of fuel on kiln surface Kiln surface fugitive emissions

High Emissions on kiln surface Self ignition/combustion of biomass on kiln surface

Self ignition/combustion of biomass on kiln surface Thick smoke from chimney during heavy biomass feeding



Output of loose biomass fired bricks (conventional)

M/s J.O. Co., Fazilka

M/s S.S. Bricks, Muktsar



5.2 Energy Performance & Specific Energy Consumption- Baseline A complete record of fuel feeding, number of bricks fired, average weight of bricks was noted during the audit. Flue gas monitoring was done at regular intervals in the brick settings near the working side flue. The performance of the kiln is tabulated in the Table-5.4 below:

Table-5.4: Flue Gas Analysis of BTKs – Baseline Study Kiln Name M/s J.O. Co.,

FazilkaM/s S.S. Bricks, Muktsar

Date 23.04.2014 10.5.2014 Time average O2 (%) 8.2 9.6

Time average CO2 (%) 11.2 9.9 Time average CO (ppm) 12710 4615 Average excess air (%) 94.9 107 Avg. temperature of flue gas (oC) 169.6 69.5

Fuel Biomass Coal/ Biomass No. of feeding rows Single line feeding Single line feeding

The variation in concentration of O2, CO & CO2 during the feeding and non feeding cycle has been shown in the figures below:

Flue Gas Analysis- Trial 1 (Concentional- Biomass feeding)

0

2000

4000

6000

8000

10000

1200014000

16000

18000

20000

22000

24000

26000

14:0

0:00

14:0

5:00

14:1

0:00

14:1

5:00

14:2

0:00

14:2

5:00

14:3

0:00

14:3

5:00

14:4

0:00

14:4

5:00

14:5

0:00

14:5

5:00

15:0

0:00

15:0

5:00

15:1

0:00

15:1

5:00

Time

Car

bon

Mon

oxde

(ppm

)

0

2

4

6

8

10

12

14

16

18

CO (ppm) O2(%) CO2(%)

Figure-5.1: Flue gas analysis during conventional operating practices – M/s. J O & Co.

O2 %

& C

O2 %



Flue Gas Analysis- Trial 2 (Coal/biomass feeding)

02000400060008000

1000012000140001600018000200002200024000

14:4

0:00

14:4

5:00

14:5

0:00

14:5

5:00

15:0

0:00

15:0

5:00

15:1

0:00

15:1

5:00

15:2

0:00

15:2

5:00

15:3

0:00

15:4

0:00

15:4

5:00

15:5

0:00

15:5

5:00

16:0

0:00

16:0

5:00

16:1

0:00

16:1

5:00

16:2

0:00

16:2

5:00

16:3

0:00

16:3

5:00

16:4

0:00

16:4

5:00

16:5

0:00

16:5

5:00

17:0

0:00

17:0

5:00

17:1

0:00

17:1

5:00

17:2

0:00

17:2

5:00

17:3

0:00

17:3

5:00

17:4

0:00

17:4

5:00

17:5

0:00

Time

Car

bon

Mon

oxde

(ppm

)

0

2

4

6

8

10

12

14

16

18

CO(ppm) O2(%) CO2(%)

Figure-5.2: Flue gas analysis during conventional operating practices M/s. S.S. bricks As evident from the above figures, there is a rapid increase in CO & CO2 levels at the time of biomass charging. Very high CO concentration range of 5000 to 24,000 ppm was observed during biomass charging. Whereas, the CO concentration in flue gas during coal charging (figure-5.4) was below 4000 ppm. This is due to the reason that biomass has very high volatile percentage of carbon which requires longer firing zone to burn it completely. However, the firemen in these brick kilns adopt the practice of heavy feeding of biomass after long intervals. Moreover, the surface temperature in the firing zone of biomass fired kiln was very high due to self ignition of biomass on the kiln surface and hence the firemen were reluctant to adopt the practice of fuel feeding in two or three rows simultaneously. Leakages from the top of brick settings were observed due to lesser thickness of insulation layer.

Based on the audit studies conducted, the specific energy consumption of the kilns with existing practices has been calculated in the Table-5.5, below:

Table-5.5: Specific Energy Consumption of BTKs – Baseline Kiln Name Fuel

Consumption (in kg)

Brick Production Specific Energy Consumption (SEC) (MJ/kg fired bricks)

M/s J.O. Co., Fazilka

Mustard straw(3985)*

bricks fired/day

Mass of fired bricks (in kg)

1.69

26526 100000 261000M/s S.S. Bricks, Muktsar

Coal (5500)*

Mustard straw (3985) *

bricks fired/day


1.48

3000 21600 100000 289000* Calorific value (CV) of fuel in KCal/kg

Mustard straw Coal feedingMustard

straw

O2 %

& C

O2 %



6.0 Pilot Scale Studies Using Briquettes

Briquettes comprising paddy straw and biomass in ratios of 15:85; 30:70 and 50:50 manufactured by M/s. Shri Krishna Agro Fuels, Sangria were transferred to the two kiln sites for its pilot scale studies. Detailed discussions were held with the kiln owners and firemen for finalizing the protocol for pilot studies. Initially it was planned to conduct pilot studies in a limited width of a kiln (in 2 or 3 lines) simultaneously with conventional practice in remaining section of the kiln. Firemen were of the view that using this method, the combustion in the kiln would be affected as the behavior of briquette combustion would be different from the biomass combustion. It was then agreed to conduct the trial across the entire width of the kiln at one go. However, firemen were of firm opinion that since the combustion of briquettes is comparatively slower, need for use of coal or loose biomass supplementation shall be required. It was then decided that during the pilot studies different combinations using briquettes, biomass and coal would be tried to study the combustion behavior of briquettes before arriving at a common or most feasible feeding system for pilot or full scale studies. The firemen had to be cajoled about the benefits of using briquettes e.g. drastic improvement in working environment as during firing loose biomass, the combustion of the biomass starts at the surface because of the high surface temperature & feedhole cover temperatures and the low ignition temperature of the loose biomass.

During the pilot trials in both the kilns, extensive monitoring was done by PSCST team. One officer from PPCB, RO Faridkot visited many times during the study. Complete log of feeding and operating practices, quantity of fuel used, rows of daily brick production and combustion quality within the kiln was maintained and recorded. The quality of bricks fired during pilot study was checked and the complete analysis of brick production was noted. The details of the trials are given below: 6.1 Pilot Trial -I: M/s. J.O. & Co., Fazilka

Trial-I was undertaken at M/s J.O. Co., Fazilka from 05.05.2014 to 09.05.2014. During the trials, briquettes made out of paddy straw and biomass (ratios 15:85; 30:70 and 50:50) were used in the kiln. A total of 34 lines (about 1.29 lac bricks) were fired during the trial. Experiments by adopting different firing practices were conducted:

• Briquette feeding in one line alongwith loose biomass in different ratios. • Pure Briquette firing in two lines.



• Initial firing with briquettes followed by heavy loose biomass feeding. During the trial-I, 19.12 tonnes of briquettes having paddy straw and mustard straw in different ratios and 8.16 tonnes of loose mustard straw was used. Detailed energy audit was conducted using flue gas analyzer, heat spy, contact type thermocouple to record flue gas readings like CO%, CO2, O2 & excess air and temperature readings at surface of kiln i.e combustion zone, preheating & cooling zone and reading in the firing zone at three different sections of brick setting i.e. top middle & bottom & reading in the soaking zone. Documentation of actual fuel consumption per line, flue gas analysis during feeding & non-feeding cycles of briquettes as well as biomass was done so as to compare the losses due to incomplete combustion of fuel.

The fuel feeding and operating practices adopted during the pilot trial-1 have been given in the Table-6.1, below:

Table-6.1: Fuel Feeding and Operating Practices During Trial-I Fuels & fuel ratios used Description of Operating PracticesBriquette (15:85) & Biomass Feeding (Line 1-11):

• Briquette/ Biomass feeding done in one line (13 feed holes) • Two man firing in one line • Briquette feeding with tokris weighing 19 kgs (av.) done by

two firemen • During feeding cycle 1 tokri of briquette in each feed hole

cycle consuming 15-25 min followed by non-feeding period of 45-50 min. This was followed by 25-30 min of loose biomass feeding cycle & then non-feeding period of 25-30 min.

• The use of briquette to loose biomass by weight was 71:29. • Negligible surface emissions during briquette feeding. • More comfortable working environment.

Briquette (15:85 & 30:70) (Line 12-19):

• 100% Briquette feeding started from 9th line & and two line feeding was adopted.

• ½ tokri of briquettes were fed in each hole. • 3 times briquette feeding cycle adopted : 15-20 min feeding

followed by 20-25 min of non-feeding period • The surface emissions were almost negligible during the

feeding & the smoke from chimney was almost white in color. • The working conditions improved considerably. • The CO levels reduced to almost 1/10th as generated during

biomass combustion. • However, accumulation of briquettes/blocking of feed hole at

middle/bottom ledges was observed.



Briquette (50:50) & loose biomass feeding (mustard straw) (Line 20-34):

• Due to slow combustion of briquette, the firemen resorted to conventional practice of feeding loose biomass heavily for increasing the combustion temperature.

• Loose biomass fed in two lines very heavily • The briquette to biomass ratio used while firing was 64:36. • Fuel feeding: ½ -1 tokri of briquette in each hole/ feeding

cycle of 15-25 min followed by non-feeding period of 45-50 min, followed by 25-30 min of briquette/ biomass feeding cycle & then non-feeding period of 25-30 min & then feeding of biomass/ briquette for 20-25 min

• The last feeding cycle before closing of line ended with feeding of biomass.

• The firemen did not adhere to the recommended practice inspite of repeated request as he was not confident of achieving the firing temperature and requisite fired brick quality.

Energy Audit of kiln during Trial-I

Feeding of briquettes during Trial-I



Combustion of briquette inside the brick setting

The flue gas analysis results during the trials have been tabulated in the Table-6.2 below:

Table-6.2: Trial-I using biomass and biomass briquette in 3 ratios Date 5/5/2014 6/5/2014 7/5/2014

Time average O2 (%) 15.2 12 8.8 Time average CO2 (%) 4.9 7.8 10.7 Time average CO (ppm) 1439.1 1572.4 10061 Average excess air (%) 338 161 99.4 Avg. temperature of flue gas (oC) 59.3 61.8 190.2 Fuel Loose mustard straw/

briquette 15:85 Briquette 15:85 Loose mustard straw/

briquette 50:50 No of feeding rows Single line feeding Two line feeding Single line feeding

The variation in concentration of O2, CO2 and CO covering the feeding and non-feeding cycle has been shown in the Figures below:

Flue Gas Analysis- Trial 1 (Briquette/biomass feeding)

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

18:2

8:00

18:3

3:00

18:3

8:00

18:4

3:00

18:4

8:00

18:5

3:00

18:5

6:06

19:0

3:00

19:0

8:00

19:1

3:00

19:1

8:00

19:2

2:00

19:2

7:00

19:3

2:00

19:3

7:00

19:4

2:00

19:4

7:00

19:5

2:00

19:5

5:00

19:5

7:00

20:0

0:00

20:0

2:00

20:0

5:00

20:0

9:04

20:1

5:00

20:2

0:00

20:2

5:00

20:3

0:00

20:3

5:00

20:4

0:00

20:4

5:00

20:5

0:00

20:5

3:00

20:5

7:00

21:0

1:00

21:0

4:00

21:0

9:00

21:1

4:00

21:1

9:00

21:2

2:00

21:2

7:00

21:3

2:00

21:3

7:00

21:4

2:00

21:4

7:00

Time

Car

bon

Mon

oxde

(ppm

)

0

2

4

6

8

10

12

14

16

18

20


Figure-6.1: Flue gas analysis while using a combination of mustard straw and briquettes (paddy straw: mustard straw ratio of 15:85)-05.05.2014

Mustard straw Briquette (15:85)

Briquette (15:85)

O2 %

& C

O2 %



Figure- 6.2: Flue Gas Analysis during feeding of briquette of paddy straw and biomass in the

ratio 15:85 -06.05.2014 Flue Gas Analysis- Trial 1 (Briquette/biomass feeding)

02000

40006000

80001000012000

140001600018000

2000022000

2400026000

21:5

9:00

22:0

2:00

22:0

7:00

22:1

1:00

22:1

7:00

22:2

1:00

22:2

4:00

22:2

6:00

22:3

1:00

22:3

7:00

22:4

4:00

22:4

9:00

22:5

4:00

23:0

0:00

23:0

5:00

23:1

0:00

23:1

5:00

23:2

1:00

23:2

3:00

23:2

7:10

23:3

3:00

Time

0

2

4

6

8

10

12

14

16

18

CO (ppm) O2(%) CO2(%)

Figure-6.3: Flue gas analysis while using a combination of mustard straw and briquettes (paddy straw: mustard straw ratio of 50:50)- 7.5.14

It can be clearly seen from the flue gas analysis that heavy CO emissions take place during charging of loose biomass whereas the CO emissions during briquette firing remained below 4000 ppm. Moreover, the light colour of smoke from the stack and negligible fugitive emissions at kiln surface during the use of briquette indicated good combustion and optimal use of heat. It was also observed that the briquette combustion released heat for a long period of time and helped in maintaining temperature in the

Briquette feeding (15:85)

Mustard strawBriquette 50:50

O2 %

& C

O2 %

O2 %

& C

O2 %





soaking zone. The specific energy consumption of the different studies during trial-I has been worked out as under:

Table-6.3: Specific Energy Consumption during Trial-I Briquette/ Biomass ratio

Fuel Consumption (in kg)

Brick Production Specific Energy Consumption (SEC) (MJ/kg fired bricks)

15:85 Briquettes (3566)*


bricks fired Mass of fired bricks (in kg)

1.37

6050 3553 41,800 109,098

30:70 Briquettes (3274)*



1.08

5427 1305 30,400 79,344

50:50

Briquettes (3155)*

Mustard straw(3985) *


1.11

8400 3300 57,000 148,770

* Calorific value (CV) of fuel in KCal/kg The SEC of the kiln while using briquettes alongwith biomass has been found to be in the range of 1.08 to 1.37 MJ/kg of fired bricks which is very less in comparison to the conventionally fired methods. The main reason for the reduced energy consumption is better combustion of briquettes, low CO generation in the flue gas and negligible fugitive emissions at the kiln surface.

6.1.1 Outcome of Pilot Trial-I

The quality of fired bricks was checked after 10-12 days of firing i.e. during the withdrawal of bricks. The number of first class bricks, under fired and overburnt bricks in the each row of brick setting was noted. Large variation in the quality of fired brick was observed.

• The fired brick quality in terms of colour and strength, in the top 8-10 layers of bricks was found to be first quality and even better than the conventionally fired bricks. Whereas, 60-80% first quality bricks were found in remaining x-section of brick settings.

• However, overburnt bricks were found near the ledges provided for retaining the fuel at different levels during the brick setting. On analyzing, clogging of briquettes were found at these ledges and released heat at the ledges itself.

• The percent quality of first quality bricks fired by using briquettes in 2 lines was less and higher percentage of overburnt bricks was found. This was due to the



sustained release of heat by briquettes over a longer period of time thus resulting in overburning of bricks near the bottom of brick settings.

• There was marginal difference in the quality of bricks fired using briquettes containing all the three ratios (15:85; 30:70 & 50:50).

Otherwise, the quality of 1st number bricks was better than the conventional, which could be observed from the copper red color & ringing sound of the brick. The kiln owner suffered loss on account of increase in number of overburnt/ underburnt bricks.

Outcome of Trial- I

Quality of fired bricks is good except deformation of bricks at ledges

Improvement in brick quality Overburnt bricks

6.2 Pilot Trial -II: M/s. S.S. Bricks, Muktsar

The brick kiln was using loose biomass and coal as fuel. As conveyed by the kiln owner, quality of upper layers of bricks improved with biomass feeding. However, to improve the quality of bricks at the bottom of the brick settings, the kiln owner was using coal. After detailed discussions with the kiln owner and the firemen, it was decided to replace the coal with briquettes initially. Subsequently, the firemen would increase the



proportion of briquettes by replacing the loose biomass. 11.75 tonnes of briquettes were transferred to the kiln for pilot trials. The fireman was adamant in using briquettes as fuel, the following feeding and operating practices were adopted in the kiln:

Table-6.4: Fuel Feeding & Operating Practices Fuel used Description of Operating Practices

Briquette/ biomass feeding

• In the conventional practice fuel used was coal and biomass and it was used in the ratio 15:85.

• One line feeding was done and each line consisted of 14 holes. • The newly opened line was initially fired with briquettes followed by

biomass. • The briquette firing was done with tokries of size 32 kg and half tokri wad

fed in one hole. The feeding cycle was of 20-25 minutes followed by non-feeding cycle of 40-50 minutes. After non-feeding cycle heavy biomass feeding was done with tokries of average weight 27 kg for 35-40 minutes followed by non-feeding cycle.

• The working environment improved as lesser biomass was used hence lower surface emissions.

• Cleaning of lines with rod after feeding of briquettes (for removing clogging of lines).

• Total 23 lines were fired.

PSCST officers visit during audit at Trial-II




Table-6.5: Trial-II using biomass & biomass briquette in different ratios Date 29/5/2104 30/5/2104 31/5/2104

Time average O2 (%) 11 8.06 8.41 Time average CO2 (%) 8.8 11.24 10.97 Time average CO (ppm) 2227.9 3192 3096 Average excess air (%) 131.2 83 85.9 Avg. temperature of flue gas (oC) 187.4 200.07 232.2 Fuel Biomass &

briquette (15:85) Biomass &

briquette 30:70 Biomass &

briquette (30:70) No of feeding rows one one one

The variation in concentration of O2, CO2 and CO covering the feeding and non-feeding cycle has been shown in the Figure-6.4 to Figure-6.6 below:


0100020003000400050006000700080009000

100001100012000

6:48

:00

6:53

:00

6:58

:00

7:03

:00

7:08

:00

7:13

:00

7:18

:00

7:23

:00

7:28

:00

7:33

:00

7:38

:00

7:43

:00

7:48

:00

7:53

:00

7:58

:10

8:03

:00

8:08

:00

8:13

:00

8:18

:00

8:23

:19

8:28

:00

8:33

:00

8:38

:00

8:41

:00

8:43

:00

8:48

:00

8:53

:00

8:55

:20

8:58

:00

9:03

:00

9:08

:00

9:13

:00

9:15

:00

9:18

:00

9:21

:00

9:23

:00

9:28

:00

Time

Car

bon

Mon

oxde

(ppm

)

0

2

4

6

8

10

12

14

16

18

CO(ppm) O2(%) CO2(%) Figure-6.4: Flue gas analysis while using a combination of mustard straw and briquettes (paddy

straw: mustard straw ratio of 15:85)- 29.05.2014


0

2000

4000

6000

8000

10000

12000

14000

16000

18000

20000

19:3

9:00

19:4

4:00

19:4

9:00

20:0

4:00

20:0

9:00

20:1

4:00

20:1

9:00

20:2

4:00

20:2

9:00

20:3

4:00

20:3

9:00

20:4

4:00

20:4

9:00

20:5

3:00

20:5

8:00

21:0

3:00

21:0

8:00

21:1

3:00

21:1

8:00

21:2

3:00

21:2

8:00

21:3

3:00

21:3

8:00

21:4

3:00

21:4

8:00

21:5

3:00

21:5

8:00

Time

Car

bon

Mon

oxde

(ppm

)

0

2

4

6

8

10

12

14

16

18

20



O2 %

& C

O2 %

Mustard straw Briquette (15:85)

Briquette 30:70 Mustard straw

O2 %

& C

O2 %




0

2000

4000

6000

8000

10000

12000

14000

16000

180000:

55:0

01:

00:0

01:

05:0

01:

10:0

01:

15:0

01:

20:0

01:

25:0

01:

30:0

01:

35:0

01:

40:0

01:

45:0

01:

50:0

01:

55:0

02:

00:0

02:

05:0

02:

10:0

02:

15:0

02:

20:0

02:

25:0

02:

30:0

02:

30:1

22:

35:0

02:

40:0

02:

45:0

02:

50:0

02:

55:0

03:

00:0

03:

05:0

03:

10:0

03:

15:0

03:

20:0

03:

25:0

03:

30:0

03:

35:0

03:

40:0

03:

45:0

03:

50:0

03:

55:0

04:

00:0

04:

05:0

04:

10:0

04:

15:0

04:

20:0

04:

25:0

04:

30:0

0

Time

Car

bon

Mon

oxde

(ppm

)

0

2

4

6

8

10

12

14

16

18



During the initial trials, the firemen used only 35% of the total fuel in the form of briquettes. To overcome the issue of blocking of ledges in brick settings, regular cleaning of feed holes using steel rod was followed. It was also observed that combustion of briquettes was taking long time resulting in slow firing of bricks. However, the CO emissions during briquette feeding were very less. It can be clearly seen from the flue gas analysis that CO emission during charging of loose biomass was very high (11000 to 18000 ppm). The specific energy consumption of the different studies during trial-II has been worked out as under:

Table-6.6: Specific Energy Consumption during Trial-II Fuel Used Fuel Consumption

(in kg) Brick Production Specific Energy

Consumption (SEC) (MJ/kg fired bricks)

briquettes/ biomass firing

Briquettes 15:85

(3566)*

Mustard straw

(3985)*

bricks fired/day

Mass of fired bricks(in kg)

1.11

3120 6372 47,400 136,986

Briquettes 30:70

(3274)*

Mustard straw

(3985)*

bricks fired/day

Mass of fired bricks(in kg)

1.14

3510 5692 43,450 125,570

*Calorific Value (CV) of fuel in KCal/kg

Briquette 30:70 Mustard straw Briquette 30:70

O2 %

& C

O2 %



Out of the 11.75 tonnes of briquettes supplied, only 6.75 tonnes briquettes were used in 3 days as the firemen was adamant in adopting suggestions and was taking long time for firing of briquettes. It was then decided to shift the remaining lot to the kiln site where trial-I was conducted for the remaining studies. It is worth noting that the SEC of the kiln during the trial has reduced to 1.11 to 1.14 MJ/kg fired bricks against the SEC of 1.48 MJ/kg fired bricks observed during baseline studies.

6.2.1 Outcome of Pilot Trial-II

The quality of fired bricks during trial-II was at par with the conventionally fired bricks. Moreover, the quality of bricks was consistent throughout the section of brick setting and in some lines the brick quality was better than the conventional coal/ biomass fired bricks. Overall reduction in surface emissions due to surface combustion of loose biomass & reduction in stack emissions. The kiln owner was satisfied with the overall brick quality.

Outcome of Trial- II

6.3 Pilot Trial -III: M/s. J.O. & Co., Fazilka

After assessing the quality of bricks produced during trial-I, the short comings in the feeding and operating practices adopted during the trial were identified. Motivated by the partial success in the trial and reduced energy consumption, the kiln owner conducted further trials by using briquettes made out of saw-dust alongwith loose biomass as fuel in subsequent brick firing. Discussions were held with the kiln owner and he offered kiln for conducting trial-III with the remaining briquette lot.



The kiln Trial-III was again undertaken and the fireman & the kiln owner were confident with the experience gained from Trial-I. The remaining briquettes of ratio 30:70 & 50:50 were shifted from M/s S.S. Bricks, Muktsar to the site. A total of 19 lines were fired & following methodology was adopted during firing:

• Briquette feeding in one line alongwith loose biomass in different ratios. • Initial firing with briquettes followed by heavy loose biomass feeding.


Table-6.7: Trial -III using biomass and biomass briquette in different ratios Date 2/6/2014

Time average O2 (%) 12.2Time average CO2 (%) 7.6

Time average CO (ppm) 4051Average excess air (%) 178

Avg. temperature of flue gas (oC) 67.4Fuel Biomass/ briquette 50:50

No of feeding rows Single The variation in concentration of O2, CO2 and CO covering the feeding and non-feeding cycle has been shown in the Figure-6.7.


0

2000

4000

6000

8000

10000

12000

14000

16000

17:4

5:00

17:5

0:00

17:5

5:00

18:0

0:00

18:0

5:00

18:1

0:00

18:1

5:00

18:2

0:00

18:2

5:00

18:3

0:00

18:3

5:00

18:4

0:00

18:4

5:00

18:5

0:00

18:5

5:00

19:0

0:00

19:0

5:00

19:1

0:00

19:1

5:00

19:2

0:00

19:2

5:00

Time

Car

bon

Mon

oxde

(ppm

)

0

2

4

6

8

10

12

14

16

18


Figure-6.7: Flue gas analysis while using a combination of mustard straw and briquettes (paddy straw: mustard straw ratio of 50:50)- 02.06.2014

The specific energy consumption of the different studies during trial-III has been worked out as under:

Briquette feeding

Mustard straw

O2 %

& C

O2 %



Table-6.8: Specific Energy Consumption during Trial-III Fuel Use Fuel Consumption

(in kg) Brick Production Specific Energy

Consumption (SEC) (MJ/kg fired bricks)

Briquettes/ Biomass firing

Briquettes 50:50 (3155)*

Mustard straw

(3985) *

bricks fired

Mass of fired bricks

(in kg)

1.06

5078 7956 73,150 190,922

*Calorific Value (CV) of fuel in KCal/kg

Adopting improved feeding and operating practices in the kiln resulted in substantial reduction in specific energy consumption of brick kiln from conventional SEC of 1.68 MJ/kg fired bricks to 1.06 MJ/kg fired bricks. Moreover, better working environment due to reduction in fugitive emission was also achieved.

6.3.1 Outcome of Pilot Trial-III

Due to inclement weather, the firing in the kiln was stopped before time. The quality of bricks in terms of colour and strength was better than the Trial-I. The owner was satisfied with the results.

Outcome of Trial-III



7.0 Summary of Pilot Trials As brought out in chapter 6, baseline studies were carried out in both the kilns before carrying out the pilot studies using briquettes. The summary of outcome of these trials viz-a-viz baseline using conventional method is tabulated in the Table-7.1, below:

Table-7.1: Summary of Pilot Studies

M/s J.O. Co., Fazilka M/s S.S. Bricks, Muktsar M/s J.O. & Co., Fazilka

Baseline Trial-I Baseline Trial-II Trial-IIIFuel Type 100%

Biomass (mustard straw)

71% briquettes & 29% loose biomass

12% coal & 88% loose biomass

35% Briquettes & 65% loose biomass

39% Briquettes & 61% loose

biomass

SEC in MJ/Kg of fired brick

1.69 1.19(1.08-1.37)

1.48 1.13(1.11-1.14)

1.06

Bricks fired (in lacs)

1.29 0.92 0.72

Brick Quality First Quality 80-85% 75-80% 85% 85-90% 85%

Second quality 8-10% 6-8% 5-10% 8-12% 10%

Over Burnt 3-5% 15-20% 5-10% 2-3% 5%

From the outcome of three trials conducted it can be broadly inferred as under:

1. During trial-I, various feeding & operating practice combinations such as one line feeding with briquette & loose biomass (except paddy straw), 2 line feeding with briquettes only and 2 line briquette/ biomass feeding were experimented. Although the quality of first class bricks was better in comparison to the conventionally fired bricks, percentage of second quality & overburnt bricks increased due to accumulation of briquettes over the ledges provided in the brick settings. This could be due to (a) conventional brick setting pattern for routine loose biomass (b) accumulation of briquettes on the ledges due to over feeding of fuel and also not clearing the ledges in the feed hole frequently. The lessons learnt during trial-I such as use of steel rod for cleaning of ledges before subsequent feeding of biomass/closing of feed holes, were adopted during the subsequent trials.

2. In trial-II, Coal was totally replaced with briquettes & the briquette-loose biomass ratio was kept almost 35:65 against coal-loose biomass % ratio of 12:88. Only 23 rows of bricks could be fired and the remaining trial had to be shifted due to the non-cooperation by the firemen as they were not agreeing to increase the percentage of briquettes during feeding & were resorting to loose biomass feeding



practice. Regarding the quality of fired bricks, only 13 rows could be inspected and the brick quality was found to be at par/ better than the conventionally fired bricks. The kiln owner expressed his satisfaction with the overall outcome.

3. Lessons learnt from trial-I were practiced in trial-III which is evident from the fact that kiln owners and firemen insisted to do experimentation in their kiln again. 19 rows of bricks were fired out during trial-III. Visible improvement in the quality of fired bricks was observed in comparison to the trial-I in the same kiln and by the same firemen. The quality of bricks at the bottom layer of brick settings (raddas) was better than that of the conventionally fired bricks.

Total quantity of paddy straw and biomass used during the trials has been worked out in Table-7.3. The per tonne cost of briquette produced for trials has also been worked out in Table-7.4

Table-7.3: Paddy straw & biomass consumption in Trials Fuel used Trial-1 Trial-2 Trial-3 Total

Total brick Production

Paddy straw in briquettes 6.52 T 1.47 T 2.34 T 10.33 T

2.93 lacs

Mustard straw in briquettes 12.6 T 4.96 T 2.34 T 19.9 T

Cow dung in briquettes 0.72 T 0.14 T 0.41 T 1.27 T

Mustard straw in loose form 8.16 T 12.06 T 7.96 T 28.18 T

*In all trials briquettes with paddy straw to biomass ratio (15:85, 30:70 & 50:50) were tried. The above percentage of paddy straw usage includes average of all the 3 ratios of paddy straw & biomass (i.e. 15:85; 30:70 & 50:50). However, difficulties were encountered during the manufacturing of briquettes containing 50% paddy straw. Subsequent discussions with the briquette machinery manufacturers revealed that briquettes with 50% paddy straw can be produced with the latest available technology. Even one of the briquette manufacturer subsequently produced briquettes with higher percentage of paddy straw which were subsequently used during full scale trials.

Table-7.4: Cost towards briquette manufacturing S.

No. Input Material/ Work Avg. Cost of one ton of briquette /

( range value) (in Rs.) 1. Cost of Pulverized Paddy straw 1400

(1200-1600) 2. Transportation of pulverized paddy straw 2573**

(2098-3048) 3. Total cost of pulverized paddy straw at briquette

manufacturing site 3973

(3498-4448) 4. Biomass cost (including transportation) 3000

(2500-3500)



5. Briquetting 1700 (1500-1900)

6. Transportation of briquettes 636.5 (550-723)

7. Cost of cow dung 1500 (1300-1700)

Cost of briquettes/tonne a) Briquette with Paddy straw & mustard straw in

the ratio 15:85 5400

(4842-5958) b) Briquette with Paddy straw & mustard straw in


(4984-6093) c) Briquette with Paddy straw & mustard straw in


(5174-6274) ** The transportation of pulverized paddy straw/paddy straw will decrease drastically as the project activity

was performed during the wheat harvesting season & due to inclement weather the transportation cost are exaggerated in this period

Since limited briquette manufacturers agreed to supply briquettes of required specifications for trial purposes, the cost of production ranged between Rs. 4800/- to Rs. 6000/- per ton including transportation of pulverized material to the briquetting site and briquettes to the kiln site. Once the efficacy & use of briquettes as fuel is established, more briquette manufacturers are likely to adopt the use of paddy straw in briquettes. As such the cost of briquettes per ton would come down.



8.0 Phase-II: Full Scale Trials

Pilot trials were conducted and it was established that 50% of the total fuel quantity can be replaced with briquettes (made from paddy straw & other biomass mix in the ratio of 50:50) as fuel alongwith loose biomass/coal. Interaction with kiln owners transpired that most of the kilns in Central & Northern districts use coal as fuel as loose biomass is not easily available. Moreover the quality of fired bricks is comparatively inferior in case of biomass fired bricks. Further discussions with BKOs revealed that around 1000 brick kilns use press mud/saw dust briquettes in limited quantity across the State. A few kilns have reportedly been using mustard straw/ guar husk briquettes sold by briquette manufacturers in neighboring state of Rajasthan.

8.1 Selection/ Identification of Kilns After the success of pilot trials, Council could identify a few progressive BKO’s in Moga/ Ludhiana/ Malerkotla/ Amritsar who own both briquette manufacturing units as well as brick kilns. These entrepreneurs manufacture saw dust/press mud briquettes and use briquettes (40% to 100% of the total fuel requirement) alongwith coal in brick kilns. Since paddy straw is abundantly available throughout the State, it was decided to manufacture briquettes from paddy straw in combination with locally available biomass/ bio-residue and demonstrate its use in other districts as well. This would act as a demonstration for more than 2000 kilns in Central & Northern Punjab and would encourage BKOs to adopt the use of paddy straw as fuel. Two kilns for final trials were identified one in district Moga & other in district Ludhiana with the details as:

Name of kiln Daily production capacity

Fuel used

M/s Burj Hakima Gram Udyog, Vill. Burj Hakima, Raikot, Ludhiana

40,000 Press mud briquettes & coal

M/s AS Brick Industries, Vill. Jalalabad East, Moga

40,000 Press mud briquettes

These brick kilns were already using press mud briquettes and were well conversant with usage of briquettes. Kiln owners & firemen were comfortable by replacing press mud briquettes with briquettes manufactured from a mix of paddy straw & other biomass. However, the firemen had to be counseled for minor changes in feeding



pattern as the combustion behavior of paddy straw briquette is different from that of press mud briquette.

8.2 Identification of Briquette Manufacturer During pilot trials in Southern districts of Punjab, briquette manufacturer at Sangriya (Rajasthan) was engaged for manufacturing briquettes from mustard straw/ guar husk/etc. It was decided to select a briquette manufacturer in central districts of Punjab, so as to make study more effective, expand its outreach & make the replication potential more effective. M/s Gill Brothers, Village Jalalabad East, district Moga- manufacturing briquettes from press mud/ cow dung from last 15 years- was shortlisted for the project as they agreed to be a part of the R&D activity. Further, the entrepreneur has three family kilns wherein briquettes are used as major fuel (70% to 100%) alongwith coal. The entrepreneur produced test samples with paddy straw & press mud mix and expressed satisfaction over the quality of the product. However, few modifications are required in the process for regular production of paddy straw based briquettes though the briquette machine operator was reluctant due to change in raw material & minor changes in handling of paddy straw.

8.3 R&D Efforts for Improving Briquette Manufacturing Process Conversion of paddy straw into briquette requires chopping/ pulverizing of paddy straw into 3-8 mm size. The briquetting industry faced problems in chopping of paddy straw. During the project study (both during pilot trials and full scale studies), pulverized paddy straw was purchased from M/s. Sampurn Agriventures, Fazilka. During the full scale trials, 28 tons of pulverized paddy straw was procured from the industry. Chopping of paddy straw to the required size is still a barrier, for which PSCST is already working on another project with details as:

• A R&D project on Improvement of design of paddy straw chopping machinery & briquette machinery, supported by NABARD is being undertaken by PSCST. The study aims at establishing cost effective solution for chopping/ grinding of paddy straw and manufacturing 100% paddy straw briquettes. Under the study, PSCST has collaborated with Central Tool Room, Ludhiana for developing the blades of choppers with improved metallurgy.

• Besides above, Council is also interacting the various experts/ manufacturing houses for identifying briquetting machine capable of producing paddy straw based briquettes. One such industry i.e. M/s Hitech Agro, Faridabad has already



demonstrated trials on manufacturing of 100% paddy straw briquettes and about 2.55 tons of 100% paddy straw briquettes were also used in full scale demonstration at a kiln near Moga.

8.4 Briquette Manufacturing for Full Scale Trials M/s Gill Brothers, Vill. Jalalabad East, Moga manufactured briquettes using pulverized paddy straw (supplied from M/s. Sampurn Agriventure) in combination with press mud in the ratio 50:50. These briquettes were used during full scale trials. Besides above, 2.55 tons of 100% paddy straw briquettes were produced during trials conducted at M/s Hitech Agro, Kotputli, Rajasthan in the presence of PSCST team. As briquette manufacturers in Moga & even in Sangria could not produce 100% paddy straw based briquettes, brick kiln owner showed apprehension and ascertained the quality of briquette and percentage of other additives by submerging the briquettes in water for 30 minutes. At this, no separation in the raw material was observed, thus proving that there was no other material/additive added. The kiln owner was fully satisfied with the quality of briquettes. The briquette samples were got tested from M/s. SAI Labs, Patiala and the results are tabulated as:

Table-8.1: Proximate Analysis & GCV of fuel samples Parameters Paddy straw

briquette (100%) Press mud briquettes

(100%) Briquette (paddy

straw/ press mud in the ratio 50:50)

Volatile matter ( %) 71.30 64.68 66.23 Fixed Carbon ( %) 12.19 11.96 11.43 Moisture ( %) - 0.49 0.03 Ash ( %) 16.51 22.87 22.31 Gross Calorific Value (kcal/ kg)

3621 3505 3521



9.0 Combustion Studies in Brick Kiln (Full Scale Trials): It was envisaged to start the full scale trials in December 2014 i.e. when the weather is conducive for carrying out the trials. The project activities were initiated with production of briquettes in December 2014. However, the firing of bricks using briquettes had to be stopped midway due to inclement weather conditions & heavy winter rains and thus envisaged plan got upset. The full scale trials were again initiated in last week of Feb 2015. However, brick kiln operations were again stalled all over the State due to heavy rains. Thus final trials could be initiated only in the third week of May 2015. Before the full scale studies, baseline data including Specific Energy Consumption (SEC) was generated by studying the existing conventional practices such as feeding, firing and operating practices of both the kilns. During the full scale trials, combustion monitoring was done by PSCST team using instruments like heat spy, flue gas analyzer, contact type thermometer etc.. Complete log of feeding and operating practices, quantity of fuel used, number of rows fired during study was recorded. The quality of bricks fired during trials was also analyzed. Sh. K.A.P. Sinha, IAS, Secretary Science Technology & Environment (SSTE) alongwith Dr. Neelima Jerath, ED-PSCST and other senior officers of PPCB and PSCST also visited briquette manufacturing unit and the brick kilns during the final trials.

Visit of SSTE, ED-PSCST and Senior Officers of PPCB & PSCST during final trials



9.1 Full Scale Trial-I: M/s. Burj Hakima Gram Udyog, Raikot

As brought out earlier, the brick kiln was already using press mud briquettes and coal as fuel. As per baseline studies conducted by Council, upto 75% fuel requirement is met with press mud briquettes. As informed by the kiln owner, the balance fuel in the form of coal is being used to fire bricks.

The full scale trials were conducted from 24.05.2015 to 27.05.2015. During the trials, 13.6 Tons of paddy straw press mud briquettes (in 50:50 ratio) were used in combination with coal as fuel. Around 88,660 bricks in 22 rows of brick settings were fired during the study period. Complete log of combustion analysis was noted during the final trials. Flue gas monitoring was done at regular intervals in the brick setting near the working side flue. The performance of the kiln is tabulated as below:



Table-9.1: Fuel Feeding & Operating Practices Fuel used Description of Operating Practices Briquette/ coal feeding

• Fuel feeding in two rows was done and each line consisted of 13 feedholes.

• The newly opened line was fired with briquettes followed by coal, before closing it.

• The briquette feeding was done with tokris of 35 kg capacity. On an average, one tokri was fed during one charging during feeding cycle of 15-20 minutes followed by non-feeding cycle of 30-35 minutes.

• Three tokris of briquettes were fed/ feed hole, in each firing row, followed by one cycle of coal feeding before closing it.

• The feedholes were cleared of clogging using steel rods (seenkh) after briquette feeding cycle.

Full Scale Firing Trials M/s. Burj Hakima GUS, Raikot




Table-9.2: Trial using paddy straw/ press mud briquettes & coal Date 24/5/2015 25/5/2015 25/05/2015

Time average O2 (%) 9.0 8.7 5.4

Time average CO2 (%) 10.2 10.7 7.8

Time average CO (ppm) 1382.6 2539 1724

Average excess air (%) 85.3 85.8 49.4 Avg. temperature of flue gas (oC) 215 338.9 238.9

Fuel Briquettes (50:50) & Coal

Briquettes (50:50) & Coal

Briquettes (50:50) & Coal

No of feeding rows Two Two Two

The variation in concentration of O2, CO2 and CO covering the feeding and non-feeding cycle has been shown in the Figure-10.1 to Figure-10.3 below:

Figure-9.1: Flue gas analysis while using a combination of briquettes & coal

(paddy straw: press mud ratio of 50:50)

Briquette feeding (50:50) Coal feeding




(paddy straw: press mud ratio of 50:50)


(paddy straw: press mud ratio of 50:50) From above graphs, it can be observed that during feeding of briquettes, the maximum CO levels were 3400 ppm against the CO levels of 12000 ppm during coal feeding. The time average CO2 levels flue gases in case of briquette feeding were 7.8-10.7%. From combustion analysis, it is evident that the briquette combustion take place slowly and it releases heat over a period of time whereas coal combustion takes place within a span of 10-30 minutes which depends upon the size & quantity of coal fed in each feedhole at

Coal feeding


Briquette feeding (50:50) Coal feeding



one time. Heavy feeding of coal per cycle releases high CO emissions indicating poor combustion. During coal feeding, the firemen were motivated to reduce the coal feeding for improving combustion. However, firemen were reluctant in reducing the quantity of coal being fed. The Specific Energy Consumption (SEC) has been worked out on the basis of baseline audit studies and full scale trials as under:

Table-9.3: Specific Energy Consumption during Full Scale Trial-I Fuel used Fuel Consumption

(in kg)

Brick Production

Specific Energy Consumption (SEC) (MJ/kg fired bricks)

Briquette & coal

Briquettes Coal Bricks fired (nos.)


1.07 (3521)* (6800)*

13618 2671 88,660 2,57,114 *Calorific Value (CV) of fuel in Kcal/kg

It is worth noting that the SEC of the kiln during the trial has come down to 1.07 MJ/kg fired bricks against the baseline SEC of 1.38 MJ/kg fired bricks observed during baseline studies. 9.1.1 Output Quality of Fired Bricks Encouraging results were observed as the quality of fired bricks was at par with the conventionally fired bricks. In addition, the quality of bricks was consistent throughout the section of brick setting. The kiln owner expressed his satisfaction and informed that quality of upper layers of bricks (raddas) has even improved at a few places due to better flame length of paddy straw briquettes. Few photographs of product are shown below:

Output quality of fired bricks



9.2 Full Scale Trial –II : M/s. AS Brick Industries, Moga

Earlier the brick kiln was using press mud briquettes (70-100%) alongwith coal as supplement fuel. Pre-audit study of the kiln was carried out to understand the existing feeding, firing and operating practices. Based on the study, the Specific Energy Consumption (SEC) has been worked out as 1.40 MJ/ kg fired bricks when 95% press mud based briquettes were being used.

The full scale trials were conducted from 08.06.2015 to 11.06.2015. During the trials, 18.50 tons of paddy straw- press mud briquettes (in 50:50 ratio) were used as fuel. Only a small percentage of coal was supplemented alongwith briquettes. The firing was initiated with 100% paddy straw briquettes and 4 rows of brick settings were fired with 2.55 tons of 100% paddy straw briquettes. Remaining bricks were fired with paddy straw & press mud briquettes (50:50). A total of 1.01 lac bricks were fired in 24 rows of brick settings during the study period. During the study, combustion analysis was carried out and flue gas monitoring was done at regular intervals in the brick settings near the working side flue. The performance of kiln is tabulated below:

Table-9.4: Full Scale Trial using paddy straw-press mud briquettes & coal Date 08/06/2015 09/06/2015 09/06/2015

Time average O2 (%) 11.5 14.4 13.5 Time average CO2 (%) 8.3 5.7 6.3 Time average CO (ppm) 1319 1042.4 1205.4 Average excess air (%) 128.3 227.9 211.2 Avg. temperature of flue gas (oC) 249.9 275.2 291.8

Fuel Briquettes (100% paddy straw)

Briquettes (50:50)

Briquettes (50:50)

No of feeding rows Two Two Two



The variation in concentration of O2, CO2 and CO covering the feeding and non-feeding cycle has been shown in the Figure-10.4 to 10.6 below:

Figure-9.4: Flue gas analysis while using 100% paddy straw briquettes- 08.06.2015

Figure-9.5: Flue gas analysis while using 100% paddy straw briquettes - 09.06.2015

Figure-9.6: Flue gas analysis while using a briquettes (paddy straw: press mud ratio of 50:50)- 09.06.2015


Briquette feeding (100% paddy straw)





The CO level during feeding of briquettes was 3250 PPM which is very less as compared to CO emissions during use of loose biomass/ coal as fuel. The time average CO2 levels remained stable at 5.7-8.3% during charging as well as non-charging cycle indicating optimal combustion. This was due to the fact that the firemen were familiar with usage of briquettes & were open to suggestions of PSCST team. The colour of smoke from stack remained between hazy to colourless throughout the trial period. The Specific Energy Consumption (SEC) has been worked out as under:

Table-9.5: Specific Energy Consumption during Full Scale Trial-II Fuel Consumption

(in kg) Brick Production

Specific Energy

Consumption (SEC) (MJ/kg fired bricks) 100% paddy

straw Briquette Paddy straw/ Press

mud briquette (50:50) Coal Bricks fired

(nos.) Mass of

fired bricks (in kg)

(3621)* (3521)* (6800)*

2525.5 18528 276 100,080 302,242 1.05 *Calorific Value (CV) of fuel in KCal/kg

Use of briquettes from paddy straw and press mud mix and adoption of recommended feeding & operating practices by the kiln has resulted in substantial reduction in specific energy consumption (SEC) of brick kiln. The SEC during trials was 1.05 MJ/kg fired bricks in comparison to baseline SEC of 1.40 MJ/kg . 9.2.1 Output Quality of Fired Bricks The weather remained unpredictable throughout the last working season of brick kilns. Even the firing had to be stopped due to inclement weather. Therefore, the fired bricks quality could only be checked during its withdrawal in August 2015 wherein it was observed that the quality of bricks in terms of colour and strength was at par with conventionally fired bricks and even at certain places, the quality was better. The quality of top layers of brick fired with paddy straw briquettes was notably better than conventional fired kilns which are generally rated as class-II/under burnt. The kiln owner was quite satisfied with the output quality of bricks. Compressive strength of the fired bricks was got tested from M/s. SAI Labs, Patiala and was reported to be 14.1 N/mm2 (141 kg/cm2), which is almost 1.5 times against required strength of 100 kg/cm2 for load bearing bricks.



Output quality of Full Scale trial-II



10.0 Summary of Full Scale Trials Baseline studies were carried out in both the kilns before carrying out the full scale trials using briquettes. The summary of outcome of these trials viz-a-viz baseline using conventional method is tabulated in the Table-11.1, below:

Table-10.1: Summary of Pilot Studies M/s Burj Hakima Gram Udyog,

Raikot M/s AS Brick Industres, Moga

Baseline Full Scale Trial-I Baseline Full Scale Trial-II

Fuel Type Press mud briquettes & coal

Paddy straw/ press mud briquettes & coal

Press mud briquettes & coal

supplement

Paddy straw/ press mud briquettes &coal supplement

SEC in MJ/Kg of fired brick

1.38 1.07 1.40 1.05

Bricks fired (in lacs)

0.89 1.01

Brick Quality First Quality 80-85% 80-85% 80-85% 85-90%

Second Quality 8-10% 8-10% 10-12% 6-7%

Over Burnt 3-5% 3-5% 3-5% 3-5%

10.1 Impact on Environment PSCST has recently conducted stack emission studies from coal and biomass fired brick kilns. During the study, the stack emissions monitoring from briquette fired brick kiln was carried out, wherein emissions less than 100 mg/Nm3 were reported. The summary of the emission results is given in the table 10.2 below:

Table-10.2: Stack Emission from FCBTKs using different Fuels

Parameter FCBTK (coal)

FCBTK (loose biomass)

FCBTK (Paddy straw/ other biomass briquette)

Suspended Particulate Matter (SPM) mg/Nm3

567-1358 191-592 93-99



10.2 Cost of Paddy Straw Briquetting

The average cost of briquetting of paddy straw & press mud in the ratio 50:50 during full scale trial has been worked out as Rs. 4550/- per ton. This includes cost towards transportation of pulverized paddy straw from Fazilka to briquetting site at Moga and transportation of briquettes to project site. However the briquetting of paddy straw and press mud/other biomass upto a ratio of 70:30 is feasible and can be used in brick kiln firing. It is envisaged that few entrepreneurs or some consortium of kiln owners would set up a central facility for producing briquettes (including chopping/ grinding facilities) near cluster of kilns which are otherwise located near agricultural land, thus reducing transportation cost on account of raw material as well as briquettes. With all these facilities, a cost projection of briquettes of paddy straw and biomass/ bio-residue in the ratio 70:30 has been worked out as Rs. 3480/- per ton as per detail given in the table 10.1.

Table-10.3 : Current &Projected Cost of Briquette manufacturing

S. No.

Input Material/ Work Avg. Cost of briquette of Paddy Straw alongwith biomass/ bio-residue in the ratio (Rs./ton)

Ratio 50:50 Ratio 70:30 (Projected)

1. Cost of Pulverized Paddy straw 1400 1400

2. Transportation of pulverized paddy straw

1500

3. Cost of biomass/bio-residue 2500 2500 4. Briquetting 1600 1500 5. Transportation of briquettes 250 250 Cost of briquettes/tonne 4550 3480

10.3 Economic Viability of Paddy Straw Briquetting In Punjab, press mud/ saw dust/ cow dung briquettes are available @ Rs.4000-5000 per ton with GCV 2500-4000 kcal/kg. The briquetting is being done in conventional briquetting machine suitable for high density raw materials only. Paddy straw being a low bulk density product could not be briquetted in present set of machines. Under the present project, press mud/ other high density biomass was mixed with paddy straw to manufacture briquettes.



Further the per ton cost of press mud and saw dust varies from Rs.1500-2500 (bone dry) & Rs.3000-3500, whereas paddy straw is presently available at Rs1200-1500 per ton. Thus paddy straw is a cheap fuel with GCV varying from 3200-3500 kcal/kg.

Cost of Machine along with other auxiliary equipments/infrastructure required and working capital was assessed after interacting with briquette machine manufacturer, briquette manufacturers/ paddy straw suppliers etc. The summary of investment is as below:

Table-10.3 : Summary of Investment Item Unit Value

Investment Cost Rupees(Rs.) 11,400,000 Operation & Maintenance Cost Rs./yr 7,680,000 Electricity requirement kWh/yr 413,463 Operating Period year 10 Unit price of electricity purchased from PSPCL Rs./kWh 6.50 Discount rate % 10.00 Price of biomass to be purchased (10% wastage) Rs./T 1,320 Briquette production T/yr 6,400 Price of briquettes to be sold Rs./T 3,500

The IRR of the project has been worked out as 18% with simple payback period of 3.18 years which makes the project financially viable even at a sale price of Rs.3500/- per ton.

At this pricing the briquetting project is a win-win situation for both investor & the buyer. The fuel cost works out be Re.1 per 1000 kcal as compared to conventional coal firing which is Rs 1.30 to Rs 1.40 per 1000 kcal.



11.0 Best Operating Practices (BOPs) during use of Briquettes as Fuel

1. Briquettes should be stored under shed otherwise the briquette would disintegrate after coming in contact with water.

2. The briquette length & diameter should be between 40 mm to 65 mm. Large size briquettes tend to clog the feeding line in brick setting.

3. If the size of briquettes is larger or distance between brick settings is uneven, the briquette clogs the line and lead to overheating at that particular zone, besides accumulation of briquettes in that area. This leads to overburning/ melting of bricks.

4. Fuel feeding in FCBTKs should be done in minimum 2 rows (using briquettes) of brick setting. This will increase the length of firing zone and improve combustion efficiency thereby reduce the stack emissions.

5. Heavy feeding of briquettes at every charging cycle should be avoided. During every charging, the quantity of briquette in each feed hole should preferably be kept less than 25kg.

6. Clearing of ledges in brick settings should be done using steel rods (seenkh) after feeding of briquettes/ before starting the next feeding cycle.

12.0 Inferences Based on the successful trials during Pilot Scale & Full Scale Studies carried out by Council during the last two working seasons of brick kilns, the following inferences have been drawn: • Paddy straw can be used as fuel in the brick kilns after converting it into briquettes

of size 40mm to 65mm. • During full scale trials, 75-90% of fuel requirement was substituted with briquettes

made from paddy straw and press mud (50:50 ratio). The results have been encouraging. However, it required continual supervision of kiln owner and PSCST team during trials, even though firemen were already conversant with the use of briquettes as fuel. It is, therefore, inferred that upto 50% of total fuel requirement can safely be replaced with briquettes made from a mix of paddy straw & other biomass/ bio-residue.



• Training to firemen would be required to adapt to the new fuel. Best Operating Practices (BOPs) and guidelines have been suggested for using briquette as fuel.

• For increasing the percentage of paddy straw in briquette, modification in raw material feeding line is required. The machinery manufacturers/ briquette producers have indicated that the necessary modification can be done once demand picks up.

• Even trials conducted at the premises of one of the machinery manufacturer have proved that briquettes with 100% paddy straw can also be manufactured. However, the locally available briquetting machine are capable of producing briquettes from mix of paddy straw & other biomass/ bio-residue in the ratio upto 50:50 only.

• Chopping of paddy straw is one of the barriers. PSCST has already taken up another study with support from NABARD for improving the design and metallurgy of blades of paddy straw chopping machine.

• Details relating to combustion behavior, product quality, emission levels and Specific Energy Consumption (SEC) is tabulated below:

Table-12.1: Summary of Outcome of Pilot/ Full Scale Trials Characteristics

Paddy Straw Briquette Firing Loose biomass/ coal /other fuel

firing Source of Raw Material • Paddy straw an agro-waste

abundantly available locally • Biomass purchased from

Rajasthan & Coal from Assam/ Jharkhand/ US/ etc.

Transportation cost • Available locally – associated transportation costs is negligible

• High, as fuel is imported from other Indian States & Countries

• The density of briquettes is 6-7 times in comparison to loose biomass. Hence briquette transportation cost is less

• High cost of transportation of biomass

Storage & Handling of fuel

• Additional cost of energy inputs associated while briquetting of biomass

• Storage area requirement reduces

• Briquette handling cost less

• Loose biomass directly fed into kiln, thus no associated cost involved.

• Firemen are paid higher wages for handling and feeding loose biomass.

• Large storage area required.



Characteristics

Paddy Straw Briquette Firing Loose biomass/ coal /other fuel firing

Fuel Combustion • Initial briquettes feeding in 2-3 rows of brick setting followed by biomass/coal feeding.

• Improved combustion due to longer firing zone

• Controlled combustion with fuel burning for long duration

• Biomass is fed in 1-2 row of brick setting.

• Dark smoke from stack due to incomplete combustion resulting in escape of unburnt volatiles/ carbon.

Specific Energy Consumption

1.05 to 1.07 MJ /kg of fired bricks 1.3 to 1.7 MJ /kg of fired bricks

Emissions • Proper firing- negligible fugitive & stack emissions.

• Smoke color hazy to colorless throughout

• Unscientific feeding of biomass in single row- resulting in high fugitive & stack emissions.

• Dark smoke during charging cycle and hazy to colorless during non-charging cycle.

• Negligible fugitive emissions and hence better working environment.

• High fugitive emissions due to self ignition of biomass on kiln surface itself during feeding cycle.

Health Hazards No health hazard to firemen in case of briquette firing

Firemen are exposed to thermal as well as gaseous emissions because of high surface temperature at kiln top and fugitive emissions.

Quality of fired product • Uniform product quality except near ledges

• Quality of bricks at top and bottom layers of brick setting comparatively better

• In loose biomass fired bricks, bottom layers of bricks remains under burnt.

• The product quality varies at different layer of brick settings.



13.0 Way Forward

• There is a need for demonstration of paddy straw based briquetting unit which can supply briquettes to a cluster of 5-8 kilns. PSCST has already submitted a proposal on “Gainful utilization of paddy straw as fuel to replace fossil fuel in two Geographical regions of Punjab” to MoEF &CC, GoI under the Climate Change Adaptation Program.

• The successful demonstration of paddy straw based briquetting plants and its utilization in kilns in two geographical regions of Punjab will encourage entrepreneurs/ brick kiln owners for adaption of paddy straw briquette manufacturing technology in other parts of the State.

• The industry needs to be sensitized before recommending any regulation on replacement of fuel as the workforce is not trained to use fuel in briquette form & incorporating new fuel will certainly be opposed by the workforce. Further paddy straw collection mechanism is not in place all over Punjab.

• For wider dissemination of the outcome of the project activity, awareness programmes (onsite training and exposure visits) for the kiln owners & firemen are required on continual basis so as to sensitize them about the benefits of using briquettes manufactured from locally available paddy straw.

• Incentives in the form of subsidies on the paddy straw based briquette manufacturing equipment, exemption on sale tax on briquettes (as applicable in the State of Rajasthan) needs to be given for promoting use of paddy straw in brick kilns.

• It is proposed that the shift towards the usage of paddy straw as fuel should be in phased manner with association of Industry.

The successful adaption of use of paddy straw as fuel would lead to consumption of more than one million tons of paddy straw from 2 lac hectares of agricultural land annually.


Punjab State Council for Science & Technology P a g e | i

Executive Summary

Punjab is an agricultural State and considered as food bowl of India. It is one of the leading producers of the most consumed crops like wheat & rice. These crops besides giving food grain, produces large amount of agro-waste. Annual paddy production is 10.54 million MT and 17-18 million MT paddy straw is generated. Out of the total paddy straw generated, 85-90% is burnt in fields thus releasing Green House Gases/ dust particles in the environment. The issue of paddy straw burning is a national/ global problem.

Presently, on an average, only 10-15% paddy straw is being used along with other biomass as fuel by biomass based power plants. While using paddy straw as fuel, these power plants are facing operational problems due to the presence of potassium, chlorides and high silica in the paddy straw. Moreover, the collection & transportation of biomass is another issue.

The burning of paddy straw is one of the major environmental issue/concern for the State and the Government has formulated a draft policy for Management and Utilization of paddy straw in which utilization of biomass-paddy straw briquettes in brick kiln is one of the options. Punjab Pollution Control Board (PPCB) had awarded a study to Punjab State Council for Science & Technology (PSCST) to establish the use of paddy straw as fuel in brick kilns. The scope of work included identification of issues involved in use of paddy straw as fuel; production of paddy straw briquettes in combination with biomass/bioresidue; conduct pilot studies on combustion behaviour of paddy straw rich briquettes and quality of output (bricks); finalize the protocol for feeding, firing practices in brick kiln based on the outcome of pilot study and Full scale trial for 2-3 days in two brick kilns using most optimal ratio.

The study was initiated in January 2014 and 3 pilot trials were conducted during the working season March to June 2014 in the southern districts of Punjab. About 2.80 lac bricks were fired in two kilns using briquettes made from a mixture of paddy straw and other biomass in different ratios (15:85; 30:70 & 50:50) alongwith loose biomass/ coal. It was established that upto 50% biomass/ coal being used as fuel in brick kilns can be safely replaced with briquettes (containing paddy straw and other biomass in 50:50 ratio). However, the firemen need to be educated and motivated for adopting the new fuel.

The full scale trials were conducted in two kilns in the districts of Ludhiana and Moga during the last working season. Unprecedented and un-timely rains resulted in delay in final trials as firing had to be stopped during trials on two occasions, i.e. February and March 2015. About 2.0 lac bricks were fired in two kilns using briquettes made from a mixture of paddy straw and press mud in the ratio 50:50. About 2.55 tons of trial briquette samples were also made with 100% paddy straw which were used as fuel in brick kiln near Moga. In one brick


Punjab State Council for Science & Technology P a g e | ii

kiln near Moga, more than 90% conventional fuel was replaced with briquettes and in second kiln near Raikot, upto 75% fuel was replaced with briquettes.

The quality of fired products was at par with conventionally fired bricks. The Av. Crushing strength of the bricks has been checked and is more than 12 N/mm2 against the PWD desired requirement of 10 N/mm2.

The Stack Emissions from Briquette fired brick kiln were observed less than 100 mg/Nm3 against the stipulated emission standard of 750 mg/Nm3.

The average cost of briquetting of paddy straw & press mud in the ratio 50:50 during full scale trial has been worked out as Rs. 4550/- per ton, including cost towards transportation of pulverized paddy straw from Fazilka to briquetting site at Moga and transportation of briquettes to project site. However the briquetting of paddy straw and press mud/other biomass upto a ratio of 70:30 is feasible and can be used in brick kiln firing. It is envisaged that few entrepreneurs or some consortium of kiln owners would set up a central facility for producing briquettes (including chopping/ grinding facilities) near cluster of kilns which are otherwise located near agricultural land, thus reducing transportation cost on account of raw material as well as briquettes. With all these facilities, a cost projection of briquettes of paddy straw and biomass/ bio-residue in the ratio 70:30 has been worked out as Rs. 3480/- per ton. The economic viability of the project has been ascertained taking into consideration local market rates of machine and other consumables. The IRR of the project has been worked out as 18% with simple payback period of 3.18 years which makes the project financially viable even at a sale price of Rs.3500/- per ton.

Thus, the briquetting project is a win-win situation for both investor & the buyer. The fuel cost works out be Re.1 per 1000 kcal as compared to conventional coal firing which is Rs 1.30 to Rs 1.40 per 1000 kcal.

Based on the successful trials during pilot scale & full scale studies carried out during the last two working seasons of brick kilns, the following inferences have been drawn:

• Paddy straw can be used as fuel in the brick kilns after converting it into briquettes of size 40mm to 65mm.

• During full scale trials, 75-90% of fuel requirement was substituted with briquettes made from paddy straw and press mud (50:50 ratio). The results have been encouraging. However, it required continual supervision of kiln owner and PSCST team during trials, even though firemen were already conversant with the use of briquettes as fuel. It is, therefore, inferred that upto 50% of total fuel requirement can safely be replaced with briquettes made from a mix of paddy straw & other biomass/ bio-residue.

• Training to firemen would be required to adapt to the new fuel. Best Operating Practices (BOPs) and guidelines have been suggested for using briquette as fuel.


Punjab State Council for Science & Technology P a g e | iii

• For increasing the percentage of paddy straw in briquette, modification in raw material feeding line is required. The machinery manufacturers/ briquette producers have indicated that the necessary modification can be done once the demand picks up.

• Even trials conducted at the premises of one of the machinery manufacturer have proved that briquettes with 100% paddy straw can also be manufactured. However, the locally available briquetting machine are capable of producing briquettes from mix of paddy straw & other biomass/ bio-residue in the ratio upto 50:50 only.

• Chopping of paddy straw is one of the barriers. PSCST has already taken up another study with support from NABARD for improving the design and metallurgy of blades of paddy straw chopping machine.

The summary of benefits of paddy straw briquette firing over other fuels is tabulated as: Characteristics

Paddy Straw Briquette Firing Loose biomass/ coal firing

Direct Benefit • Fuel locally available in the vicinity of kiln

• Low transportation cost • Low carbon emissions • Lower firing cost • Specific Energy Consumption:

1.05 to 1.07 MJ/kg of fired bricks

• Better product quality

• Needs to be transported from far off places

• High transportation cost • High carbon emissions • Specific Energy Consumption:

1.3 to 1.7 MJ/kg of fired bricks• Product quality uneven

(especially in biomass fired kilns)

Indirect benefits • Utilization of locally available fuel which is otherwise burnt in the fields. Hence, reduces GHGs

• Lower carbon footprint due to transportation of fuel from nearby fields

• Better working environment

• High carbon footprint due to transportation of fuel from long distance.

Way forward

• There is a need for demonstration of paddy straw based briquetting unit which can supply briquettes to a cluster of 5-8 kilns. PSCST has already submitted a proposal on “Gainful utilization of paddy straw as fuel to replace fossil fuel in two Geographical regions of Punjab” to MoEF &CC, GoI under the Climate Change Adaptation Program.

• The successful demonstration of paddy straw based briquetting plants and its utilization in kilns in two geographical regions of Punjab will encourage entrepreneurs/ brick kiln owners for adaption of paddy straw briquette manufacturing technology in other parts of the State.

• The industry needs to be sensitized before recommending any regulation on replacement of fuel as the workforce is not trained to use fuel in briquette form &


Punjab State Council for Science & Technology P a g e | iv

incorporating new fuel will certainly be opposed by the workforce. Further paddy straw collection mechanism is not in place all over Punjab.

• For wider dissemination of the outcome of the project activity, awareness programmes (onsite training and exposure visits) for the kiln owners & firemen are required on continual basis so as to sensitize them about the benefits of using briquettes manufactured from locally available paddy straw.

• Incentives in the form of subsidies on the paddy straw based briquette manufacturing equipment, exemption on sale tax on briquettes (as applicable in the State of Rajasthan) needs to be given for promoting use of paddy straw in brick kilns.

• It is proposed that the shift towards the usage of paddy straw as fuel should be in phased manner with association of Industry.

The successful adaption of use of paddy straw as fuel would lead to consumption of more than one million tons of paddy straw from 2 lac hectares of agricultural land annually.

utilization of paddy straw as fuel in brick kilns

Documents