University of Southeastern Philippines

College of Engineering

Bo. Obrero campus, Davao City

“Fuel and Ash Handling in Boiler”

A Project presented in partial fulfillment of the requirements in

Instrumentation and Control

Presented by:

Irwin Glenn O. Jabagat

Presented to:

Engr. Benjamin Estrellado, Jr., PME

October 2010

Approval Sheet

This project entitled “Fuel and Ash Handling in Boiler” prepared and submitted by

Mr. Irwin Glenn O. Jabagat, in partial fulfillment of the requirements for the degree of

Bachelor of Science in Mechanical Engineering, has been examined and is recommended for

acceptance and approval of ORAL EXAMINATION.

Engr. Benjamin Estrellado, Jr., PME

Instrumentation and Control Engineering

Professor

Panel of Examiner

Approved by the committee on ORAL EXAMINATION with a grade of _____.

Engr. Benjamin V.D. Estrellado Jr., PME Dr. Rosello Lyndon H. Roble, PME, FPSME Chairman Member

Accepted and approved in partial fulfillment of the requirements for the

Instrumentation and Control.

Acknowledgement

The researcher wish to acknowledge with gratitude, the help given by the following

persons who made the accomplishment of this research.

To the researchers parents as well as the family members, friends and classmates for

the encouragement and their support.

The researchers would also like to give regards to all those people who helped in

doing this project.

And most especially to Jehovah god who is the source of all the knowledge and

strength for making this project possible.

Abstract

Boiler or steam generator is a machine used to produce electricity in the energy

business, especially in power plants.

The highlight of this project is on handling the coal as a fuel in the steam generators

and the fired coal or ashes as well.

The result of this study showed that the system used in this project proved to be

effective in efficient handling of the coal as well as cleaning its ashes.

TABLE OF CONTENTS

TITLE PAGE

APPROVAL SHEET

ACKNOWLEDGEMENT ----------------------------------------------------------------- i

ABSTRACT---------------------------------------------------------------------------------- ii

TABLE OF CONTENTS ------------------------------------------------------------------ iii

Chapter 1. INTRODUCTION

Background of the Study ----------------------------------------------------------

Statement of the Problem ---------------------------------------------------------

Objective of the Study -------------------------------------------------------------

Scope and Limitation of the Study -----------------------------------------------

Significance of the Study ----------------------------------------------------------

Chapter 2. REVIEW OF RELATED LITERATURE AND RELATED STUDIES

Related Literature ------------------------------------------------------------------

Related Studies ---------------------------------------------------------------------

Chapter 3. METHODOLOGY

Research procedure ---------------------------------------------------------------

Research instrument --------------------------------------------------------------

Data gathering procedure --------------------------------------------------------

Chapter 4. PROCESS ANS DISCUSSION

Chapter 5. SUMARY AND FINDINGS;

CONCLUSION, RECOMMENDATION

Chapter 1

Introduction

Steam generators are commonly used in power plants in the power plant industry.

Fuel and ash handling is one of the most important factors in the operations in boiler, this

concerns about delivering the coal fuel through the burners as well as collecting or cleaning

up the ashes.

This project provides idea about the operation on completely handling the coal fuel

and on how to clean up or collect the fired coal or the ashes.

Background of the study

The researcher was inspired to create a design on handling the coal fuel and ash

handling in boiler because of the growing industry of power plants. Through extensive

investigation with regards to the present method on handling the coal fuel and ash, the

researcher come up through a plan which uses instrumentation and control system to be used

in handling the fuel and ash in boiler.

Statement of the problem

Steam generators often encounter the following problems in handling the fuel and ash.

Inefficient ash handling, especially in a coal – fired power station environment

where large pulverized fuel ash are created.

How to recycle the burned coal.

Labor and bag costs were very high.

Objective of the study

The main purpose of this research project is to design and construct a system in handling

the coal as fuel and the ashes in boiler. Such system provides:

Proper handling on delivering the coal.

Proper handling or collecting of fired coal.

To minimized the labor cost.

To properly disposing the ash as of concerned in environment.

Definitions of terms

Coal - A wide range of coal types having either high or low fusion temperatures can

be burned. Coals having a fusion temperature down to 2000 can be burned under the

right conditions. Free Swelling or Hargrove indexes have little affect on the burning

characteristics of a spreader. The ASTM rankings for bituminous coal, sub-

bituminous coal, or lignite fit the spreader combustion process well. In general, all of

these coal types can be burned on a given unit at the same combustion heat release.

There does have to be a concern for the attributes of each coal type as it relates to

boiler furnace and gas pass design. There are plants that have substituted lower grades

of coal for cost savings as well as substituting low sulphur bituminous or sub-

bituminous coal to meet state or local emission requirements. A coal’s volatile matter

does affect the combustion process. Volatile content of 20% on a dry and ash free

basis should be considered a minimum and at that low percent, the grate heat release

should be lower.

Coal fuel handling equipments:

Storage – coal may be stored in covered bins or bunkers, in silos, or in the open. Only

relatively small amounts can be stored in bunkers and silos. The amount that can be

stored on the ground is limited only in by the space and coal handling equipment

available. If coal is to be stored on the ground, the selected area should be prepared to

reduce loss of fuel due to mixing with foreign material. The site may be leveled and

firmly packed, stabilizing materials may be used, or a concrete or asphalt surface may

be laid. Silo storage is divided between live and dead storage. The dead storage in the

silos should be shifted at least once per month. Where obvious heating occurs,

shifting of dead storage should be as often as required to minimize spontaneous

heating and to avoid fires.

Hoppers – hoppers receive coal from truck or coal cars and deliver it to feeder or

conveyor system. Hoppers usually have grates made of steel rods or bars to prevent

passage of oversized materials which could plug or damage the conveying equipment.

Feeders – many types of feeders are available to convey and regulate the flow of coal

from the hopper to the bucket elevator or other parts of the system. Apron feeders and

flight feeders are continuous chain-type feeders which are often used. Final selection

is dependent on the particular site characteristics.

Bucket elevator – a bucket elevator consists of an endless chain, twin chains, or belt

to which buckets are attached. It is used to lift coal vertically.

Bunkers and silos – bunkers and silos provide covered storage of the coal. Bunkers

are made of steel and are often lined with a protective coating to minimize corrosion

and abrasion. Hopper bottom and discharge gates are proved to remove coal from

bunker. Silos are constructed of either steel or concrete and are often provided with

live storage sections and reserve storage sections.

Coal weighing – Knowledge of the quality and quantity of coal used is essential

efficient operation of a boiler plant. No standard method of weighing coal can be

prescribed, since many types of equipment are available for doing the job manually or

automatically. Coal maybe weighed directly with weighing equipment, or indirectly

with equipment which measures its volume. Weighing equipment ordinarily consists

of automatic or semiautomatic weigh larry, it consists of a framework which supports

a hopper mounted on scale beams. The framework can be moved over the various

bunkers. The coal hopper of the larry is filled and the weigh determined and recorded.

The larry is then moved to the desired stoker hopper and dumped. Coal scales which

weigh coal automatically are also available. One type of scale consists of three major

assemblies: a belt feeder, a weigh hopper with bottom dump gate, and a weigh lever

with controls. A mechanical register is provided to record the amount of coal

delivered. A belt feeder transfers the coal into the weigh hopper until the weigh lever

is balanced. The weigh hopper is then dumped and the cycle is repeated.

Ash-handling – ash typically requires removal from several collection points in

boiler. Ash that is removed directly from the furnace or stoker is termed “bottom ash”

and may be in hard, agglomerated clinkers. Ash that is removed from various dust

collection points is termed “fly ash” and tends to be light, fluffy, and relatively free

flowing.

Instrumentation and Control:

Thermocouple – a temperature measuring device, A thermocouple is a junction

between two different metals that produces a voltage related to a

temperature difference. Thermocouples are a widely used type of temperature

sensor for measurement and control and can also be used to convert heat into electric

power. They are inexpensive and interchangeable, are supplied fitted with standard

connectors, and can measure a wide range of temperatures.

Vibration-reed frequency meter - A frequency meter consisting of steel reeds

having different and known natural frequencies, all excited by an electromagnet

carrying the alternating current whose frequency is to be measured. Also known as

Frahm frequency meter; reed frequency meter; tuned-reed frequency meter.

Weight scale - is a measuring for determining the weight or mass of an object.

A spring scale measures weight by the distance a spring deflects under its load.

A balance compares the torque on the arm due to the sample weight to the torque on

the arm due to a standard reference weight using a horizontal lever. Balances are

different from scales, in that a balance measures mass (or more

specifically gravitational mass), whereas a scale measures weight (or more

specifically, either the tension or compression force of constraint provided by the

scale). Weighing scales are used in many industrial and commercial applications, and

products from feathers to loaded tractor-trailers are sold by weight. Specialized

medical scales and bathroom scales are used to measure the body weight of human

beings.

Pressure relief valve - A pressure relief valve is a safety device that relieves

overpressure in a vessel or piping. The generic terms are pressure relief valves (PRV)

or pressure safety valves (PSV). They are a subset of pressure relieving devices

(PRD). PRDs include pressure relieving devices that are not valves, like vacuum

breakers and rupture disks.

Timer - A timer is a specialized type of clock. A timer can be used to control the

sequence of an event or process. Whereas a stopwatch counts upwards from zero for

measuring elapsed time, a timer counts down from a specified time interval, like

an hourglass. Timers can be mechanical, electromechanical, electronic (quartz), or

even software as all modern computers include digital timers of one kind or another.

When the set period expires some timers simply indicate so (e.g., by an audible

signal), while others operate electrical switches.

Control room - A control room is a room serving as an operations centre where a

facility or service can be monitored and controlled.

Mechanical vibrator - A vibrator is a mechanical device to generate vibrations. The

vibration is often generated by an electric motor with an unbalanced mass on

its driveshaft.

Significance of the study

Fuel and ash handling plays a very important role in boiler operations. Through the

right handling of fuel, the plant can lessen the expenses especially on laborers and through

proper collecting and disposing of ashes, the plant can also help the environment. This

research project will help us know how to properly handle the coals in the boiler.

Scope and limitations

This research project is designed specifically for the systems in handling the coal fuel

and ash in boiler. This project is designed in relation to the present boilers in power plants

here in the Philippines.

This project is limited only in controlling and managing small scale application such

as monitoring and controlling the variables present in the particular system.

Chapter 2

Review on related literature and related studies

Related literature

The 1712 boiler was assembled from riveted copper plates with a domed top made of

lead in the first examples. Later boilers were made of small wrought iron plates riveted

together. The problem was producing big enough plates, so that even pressures of around

50 psi (344.7 kPa) were not absolutely safe, nor was the cast iron hemispherical boiler

initially used by Richard Trevithick. This construction with small plates persisted until the

1820s, when larger plates became feasible and could be rolled into a cylindrical form with

just one butt-jointed seam reinforced by a gusset; Timothy Hackworth’s Sans Pareil 11 of

1849 had a longitudinal welded seam. Welded construction for locomotive boilers was

extremely slow to take hold. Once-through mono tubular water tube boilers as used by

Double, Lamont and Pritchard are capable of withstanding considerable pressure and of

releasing it without danger of explosion.

Since allen-sherman-hoff began supplying ash handling systems to electric utilities in

1917, the technology has advanced dramatically. As the size of steam generators has

increased, ash handling systems have also grown in capacity. Increased environmental

awareness has also caused major changes in ash handling techniques. Among the most

notable are the use of sophisticated air filtration equipment in pneumatic systems and the

increased use of closed loop recirculating hydraulic systems to constantly recycle conveying

water.

Related studies

A great many types of coal-handling equipment with capacities ranging from a few

tons to several tons per hour are available. The kind of equipment selected is determined by

such factors as size of plant, total amount of fuel to be burned, method of receiving the coal,

regularly of delivery, kinds of coal available, and relative locations of the plants and storage

areas. It is usually advantageous to keep a certain amount of coal storage, in case deliveries

are delayed for any reason. The amount if coal stored depends on the rate at which it is

burned, space available for storage and frequency of delivery. The quantity stored should

normally be sufficient to operate for 90 days or longer at peak demand.

Ash typically requires removal from several collection points in the boiler. Ash that is

removed directly from the furnace or stoker is termed “bottom ash” and may be in hard,

agglomerated clinkers. Ash that is removed from various dust collection points is termed “fly

ash” and tends to be light, and relatively free flowing. All the ash is generally handled

together and disposed of in a permitted landfill, especially on small systems. Depending on

individual circumstances, it may be desirable to segregate the bottom and fly ash and handle

them separately. This could be advantageous, for instance, if a commercial market existed for

one of the products. (Fly ash can be used in the manufacture of concrete; bottom ash may be

used as a winter road treatment). Medium size and large plants generally employ complete

ash disposal systems, while small plants may use less automatic equipment.

Chapter 3

Methodology

In this chapter, the researcher defines the research procedures, research instrument

and data gathering methods that were utilized throughout the analysis.

Research procedure:

Definitive method was used in this study, particularly, descriptive status. This design

is an approach on problem solving seeking to answer the questions to real facts to existing

conditions. This is one way of quantitative description that determines the prevailing

conditions in a group of cases chosen for a study.

Research instrument:

The researcher made use of the internet sites, pdf files, books, published and

unpublished thesis for the collection of data and information concerning with the

instrumentation and control design in handling the coal fuel and ash in steam generators.

Data gathering procedure:

In gathering the needed data for this study, the research followed the systematic

procedures below:

1. As research instrument was regarded as valid and reliable, the research proceeded to

collect article and records from the internet, books unpublished and published thesis

and dissertation with reference to instrumentation and control for handling the coal

fuel and ash in steam generators.

2. After the retrieval of the data and information, the research gathered, organization and

analyzed the process.

Chapter 4

Process and discussion

The process in coal handling starts in the hopper. The hopper conveys the coals

through the bucket elevator, and then the coal is conveyed vertically by the elevator and

drops it into the silo. The coals were stack in the silo and slowly drops the coal by a

mechanical vibrator into the funnel shaped weigh larry. Next, the weigh larry drops the coals

through the feeder’s hopper and delivers it through the burner. And as for handling the ash,

Dry ash is admitted to the primary and secondary ash receivers and the bottom ash also

admitted into the ash collecting hopper. The ash is being conveyed through an ash bin by the

use of an air pressure, which passes through a bag filter to separate the ash from air before

discharging the air into the atmosphere.

The process about instrumentation and control on handling the coal starts when the

burner demands more supply of coals. From the control room, the operator can start up the

conveyor in the hopper and the bucket elevator, and also the mechanical vibrator in which the

vibration is being monitored and controlled. The coal gate of the silo opens and drops the

coals into the weigh larry. A weight scale is installed in the weigh larry so that when the

desired amount of coal is reached, the coal gate closes and the mechanical vibrator, bucket

elevator and the hopper automatically stops its operation. Back to weigh larry, a temperature

measuring device it also installed in it to examined the temperature of the coal before

dropping it into the hopper of the feeder. When the temperature of the coal is lower than the

given sample, a heating valve automatically preheats the coals so that it can easily be burned.

When the desired temperature is reached, the coal gate in the weigh larry opens and drops the

coal through the hopper in which the coal is being delivered through the burner. As for

collecting the ash, the ash is admitted to the ash collecting hopper, which is equipped with a

level probe. As soon as the ash level reaches a fixed level in the collecting hopper, the level

probe senses its presence; it allows the system to initiate a conveying cycle. The inlet valve

opens to allow the ash to gravitate into the conveying vessel, till it closes automatically. On

closure of the valve, the conveying vessel gets pressurized and the material resistance helps

pressure build up which conveys the material through pipe in the destination silo. When

conveying is complete which is sensed by the control system, air supply to the system is

stopped and system is ready for the next cycle.

Chapter 5

Summary and findings, conclusion, recommendations

Summary and findings

The study attempts to determine the following:

Inefficient ash handling, especially in a coal – fired power station environment where

large pulverized fuel ash are created.

How to recycle the burned coal.

Labor and bag costs were very high.

Based on the data gathered by the researcher; this research projects helps to minimize the

labor expenses as well as to recycle the fired coal or ashes and to efficiently handle the fuel

and ash.

The ashes can be reused, the fly ash may be used in the manufacture of concrete and

bottom ash may be used as a winter road treatment. And by reusing the fired coals or the

bottom ash and fly ash, we can help our own environment.

Conclusion

Based on the findings of the study, the following conclusions are made; through this

project, we can formulate a various ways in handling the coal and ash in boiler systems.

Through the aid of instrumentation and control, we can easily operate and monitor the whole

system and thus we can minimize the expenses especially on labors. This project will

definitely help or serve as a guide on how to handle the systems of coal fuel and ash in boiler.

Recommendation

The researcher would like to recommend the following instruments:

Valves

Pressure-reducing valve (pressure-relief valve) – these are automatic valves that

provide a steady pressure into a system that is at a lower pressure than the supply

system. Once the valve is set, the reduced pressure will be maintained regardless of

changes.

Heating valve – these are automatic heating device, once the heating valve is set, the

reduced temperature will be maintained regardless of changes.

Measuring devices

Level probe – is a Level  that detects the level of substances that flow,

including liquids, slurries, granular materials, and powders. All such substances flow

to become essentially level in their containers (or other physical boundaries) because

of gravity. The substance to be measured can be inside a container or can be in its

natural form (e.g. a river or a lake). The level measurement can be

either continuous or point values. Continuous level sensors measure level within a

specified range and determine the exact amount of substance in a certain place, while

point-level sensors only indicate whether the substance is above or below the sensing

point. Generally the latter detect levels that are excessively high or low.

Thermocouple – a temperature measuring device, A thermocouple is a junction

between two different metals that produces a voltage related to a

temperature difference. Thermocouples are a widely used type of temperature

sensor for measurement and control and can also be used to convert heat into electric

power. They are inexpensive and interchangeable, are supplied fitted with standard

connectors, and can measure a wide range of temperatures.

Vibration-reed frequency meter - A frequency meter consisting of steel reeds

having different and known natural frequencies, all excited by an electromagnet

carrying the alternating current whose frequency is to be measured. Also known as

Frahm frequency meter; reed frequency meter; tuned-reed frequency meter.

Weight scale - is a measuring instrument for determining the weight or mass of an

object. A spring scale measures weight by the distance a spring deflects under its load.

A balance compares the torque on the arm due to the sample weight to the torque on

the arm due to a standard reference weight using a horizontal lever. Balances are

different from scales, in that a balance measures mass (or more

specifically gravitational mass), whereas a scale measures weight (or more

specifically, either the tension or compression force of constraint provided by the

scale). Weighing scales are used in many industrial and commercial applications, and

products from feathers to loaded tractor-trailers are sold by weight. Specialized

medical scales and bathroom scales are used to measure the body weight of human

beings.

Variable vibrator - A variable mechanical vibrator includes a first eccentric weight

fixed to a rotatably mounted shaft. A second eccentric weight is rotatably mounted on

the shaft, and the two weights are rotated together under control of mating

engagement abutments, one carried by the shaft and one carried by or comprising a

surface of the second eccentric weight. In one embodiment, first and second prime

movers are used to rotate the shaft and the second eccentric weight, respectively; and

when primary rotation of the shaft is effected by the first prime mover, the first and

second eccentric weights are diametrically oppositely aligned with respect to one

another on the shaft providing a balanced operation. In this mode of operation, the

abutment carried by the shaft drives the abutment on the second weight to rotate such

weight set with the shaft. A second mode of operation is effected under control of the

second prime mover which rotates the second eccentric weight to a point where the

engagement abutments engage one another in a position where the second eccentric

weight and the first eccentric weight are substantially aligned with one another on the

shaft to create an unbalanced condition. In this mode, the abutment on the second

eccentric weight drives an abutment affixed to the shaft to rotate the shaft with the

second weight. Another embodiment uses only a single prime mover, and changes in

the relative positions of the two weights are effected by static and rotational inertia as

the prime mover is speeded up and slowed down.

Pressure sensor - A pressure sensor measures pressure, typically of gases or liquids.

Pressure is an expression of the force required to stop a fluid from expanding, and is

usually stated in terms of force per unit area. A pressure sensor usually acts as

a transducer; it generates a signal as a function of the pressure imposed. For the

purposes of this article, such a signal is electrical.

Safety and Maintenance:

Conveyor belt – conveyor belt maintenance not only includes proper care of the belt itself

but also includes care and maintenance of the frame and accessories. The first step is to

inspect the conveyor belt when the system is shut down and empty. This allows the

opportunity to check for any damage to the belt of splice. The conveyor should be locked out

while making this inspection. Rubber belt damage should be repaired using the hot

vulcanized repair method or for the cold repair method. Belt fabrics that are exposed to the

weather or to product contamination should be properly cleaned, dried, and then covered with

new rubber. These repairs are critical to prevent moisture from penetrating the belt and

breaking down the cover adhesions.

Silo – wooden doors should be checked for rot and physical damage; check bolts and bolt

heads for tightness and degree of corrosion; evaluate corrosion and physical damage to door

steps latches; cast irons hinge eyes should be tightened and assessed for corrosion; concrete

door frames should be checked for deterioration and physical damage; doors must sit

properly in their frames for latch systems to work effectively; replace wire rope on the

unloader if signs of ware are evident; outside ladders should be fitted with structurally sound

safety cages to prevent falls.

Appendix

Pressure sensor

SensorLimits of application

Accuracy Dynamics Advantages Disadvantages

Bourdon “C”

Up to 100 MPa

1-5% full span

- Low cost with reasonable

Hysteresis

accuracySpiral Up to 100

MPa0.5% of full span

- Low cost with reasonable accuracy

Affected by shock and vibration

Helical Up to 100 MPa

0.5-1% of full span

- Wide limits of application

Affected by shock and vibration

Bellows Typically vacuum to 500 kPa

0.5% of full span

- -low cost-differential pressure

-smaller pressure range of application-temperature compensation needed

Diaphragm Up to 60 kPa

0.5-1.5% of full span

- Very small span possible

Usually limited to low pressures

Capacitance/ inductance

Up to 30 kPa

0.2% of full span

- - -

Resistive/ strain gauge

Up to 100 MPa

0.1-1 of

full span

Fast Large range of pressures

-

Piezoelectric - 0.5 of

full span

Very fast Fast dynamics Sensitive to temperature changes

References

http://www.wikipedia.org/

http://www.google.com.ph/

http://www.yahoo.com/

http://search.yahoo.com/search?

vc=&fp_ip=ph&p=fuel+and+ash+handling&toggle=1&cop=mss&ei=UTF-8&fr=yfp-

t-701

http://search.yahoo.com/

search;_ylt=A0oGdSXbYqNMLSYAFRVXNyoA;_ylc=X1MDMjc2NjY3OQRfcgM

yBGFvAzAEZnIDeWZwLXQtNzAxBGhvc3RwdmlkAzhnaVRzMG9HZFRCQXc3

WXJUSE85Tnd3WFFOQnNMMHlqWXRzQUE2QUwEbl9ncHMDMARuX3Zwcw

MwBG9yaWdpbgNzcnAEcXVlcnkDZnVlbCBoYW5kbGluZwRzYW8DMQR2dGV

zdGlkA0FDQk0wMg--?p=fuel+handling&fr2=sb-top&fr=yfp-t-

701&fp_ip=ph&rd=r1&meta=vc%3Dph

http://www.fuel-handling-systems.com/

http://www.whitingcorp.com/applications_detail.cgi?id_num=13

http://www.discountedheating.co.uk/shop/acatalog/

Online_Catalogue_Thermostats_306.html

http://www.freepatentsonline.com/4262549.html

http://www.engineeringtoolbox.com/

Curriculum vitae

Name: Irwin Glenn O. Jabagat

Address: blk. 1, lot 10, phase 1, Dona Asuncion Village, Bo. Pampanga, Davao City

Age: 22

Birth date: January 21, 1988 Birth place: Davao City

Father’s name: Albert B. Jabagat Occupation: canvasser

Mother’s name: Dolores O. Jabagat Occupation: Alsons properties group

manager

School Background:

Elementary: KTMSCES - 1995 – 2001

High School: DCNHS - 2001 – 2005

College: University of Southeastern Philippines - 2005 – present