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Project Report on CNG filling

Operations

Ankur Rawal

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CERTIFICATE

Certified that this project report “CNG filling Operations” at

Indraprastha Gas Limited is the work of “Ankur Rawal” who carried out the

project work under the Operations & Maintenance department.

Mr. Amit Kumar Deb

Manager (CNG - O&M)

Mr. Ujwal Bhandari

General Manager (CNG-O&M)

Mr. P.K. Pandey

Chief General Manager (CNG-O&M)

Mr. Manjeet Singh

Vice President (E&P)

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ABSTRACT

Filling operations of Compressed Natural Gas (CNG) in Natural Gas Vehicles

Natural gas is being used as an alternative fuel to gasoline. Natural Gas vehicle

(NGV) refueling stations incorporate a series of processes which make the gas

dispensable. The report focuses on understanding various aspects of these processes

and test and suggest changes in their functioning.

Various tests and observations were made on the compressor and inlet pipes

and pressure drops calculated. Useful characteristics of CNG during the fill process are

temperature, pressure, and flow rate, as well as, total volume dispensed. CNG is

dispensed to an NGV through a process known as the fast fill process, since it is

completed in less than five minutes. The system is being constantly upgraded in order

to result in lower filling time and make it comparable to that of petrol or diesel fillings.

The report also highlights the quality control operations at Indraprastha Gas

Limited (IGL). The Gas Chromatography installation at Mahipalpur Gas Station has

been carefully studied along with viscosity relations with dilution were done for snoop

solution used to test leakage.

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Acknowledgments

I wish to acknowledge all the people who have helped me finish this Report.

Without the generosity of others there is no way that I could have finished it. The report

is an outcome of the advice and tutelage of several people who work at Indraprastha

Gas Limited (IGL).

I would like to thank my advisor and mentor Mr. Ujwal Bhandari (General

Manager CNG-O&M), first of all, for being so patient with me and being an excellent

mentor throughout my time in IGL. Without the advice and knowledge of Mr. Bhandari,

the completion of this document would have been impossible. The other guides of my

endeavor, Mr. Amit Kumar Deb (Manager CNG-O&M Jail Road Control Room) and

Mr. Abhinav Sahay (Additional Manager CNG-O&M Lado Sarai Control Room)

have also been very helpful for advice and knowledge of subjects contained in this

report. The entire team of Engineers and Technicians at Jail Road and Lado Sarai

Control Rooms have in some way or the other helped me understand practical aspects

of whatever I had learnt in texts earlier.

I am highly indebted to Mr. Manjeet Singh (Vice President – E&P) for he

believed in my objectives of undergoing this internship and made an exception in

allowing me to be a part of the organization after completing the second year of my four

year graduation in Chemical Engineering.

My college, USCT has been very supportive as well, to have allowed me to use

their facilities and equipments for a few tests. University Professors such as

Dr. Biswajit Sarkar have helped me with the required textbooks and constantly

answered all my queries regarding fluid dynamics and Heat Exchangers.

Thanks and Regards,

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AN OVERVIEV OF INDRAPRASTHA GAS LIMITED

COMPANY PROFILE

Indraprastha Gas Limited (IGL), a Joint Venture of GAIL (India) limited and BPCL

along with the government of NCT of Delhi was incorporated on December 23, 1998 to

implement the compressed Natural gas (CNG) expansion program and the Piped Natural Gas

(PNG) project for varied application in the domestic and the commercial sector.

In 1999, IGL took over the Delhi City Gas distribution Project started by GAIL (India)

Ltd. which focused on supply and distribution of CNG & PNG in the capital city. Thereafter IGL

worked tirelessly to take the project to new heights.

IGL’S VISION

-‘To be the leading clean energy solution provider, committed to stakeholder

value enhancement, through operational excellence and customer satisfaction’

This vision statement signifies five major attributes of the organization.

Commitment to the environment

Providing complete energy solution and thereby going beyond CNG for transport and

PNG for cooking application

Enhancing value for beneficiaries including customers, stakeholders and employees

Achieving excellence in operations

Providing satisfaction to customer

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CNG-Compressed Natural Gas

Natural Gas is a combination of Methane, Propane and Butane. Conventional Natural

Gas exists above crude oil deposits, and is often wasted or burned in the oil collection process

due to the high costs of capturing and using it. When the gas is burned, it prevents the Methane

from reaching the atmosphere. Carbon Dioxide into the atmosphere is less harmful than

Methane.

Natural Gas produces less air pollution than any other fossil fuel. Use of CNG vehicles

can reduce Carbon Monoxide emissions as much as 93% Nitrogen Oxide reduces about

33% and Hydrocarbons are reduced by about 50%. Natural Gas emits almost no carcinogenic

particulates.

By using CNG to power vehicles a bi-fuel tank can exist; therefore, in locations without

CNG pumps, Petrol may be used by just flipping a switch. Since CNG is a clean-burning fuel,

maintenance costs are lowered. CNG is 130 octanes, which is considerably higher than 93

octanes for Petrol; consequently, the CNG vehicle is more energy efficient. Besides using

Natural Gas to power vehicles, it can also create electricity and heat homes and commercial

buildings.

Compressed Natural Gas (CNG) is natural gas that has been compressed for storage

aboard a natural gas vehicle (NGV), a vehicle whose engine is fueled by Natural Gas. Natural

gas is compressed to high pressure (200 bar/20.7 MPa or higher) to most effectively utilize the

NGV’s limited available space for storage.

ADVANTAGES DISADVANTAGES

Abundant Supplies Nonrenewable Resource

Low Emission Vehicles Decreased Range

Advanced Vehicle Developments New Refueling Sites Required

Reduced engine maintenance Expensive Engine

Modifications Inexpensive

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It is proven manifold that natural gas is a very clean fuel. The world Energy

Conference of Tokyo 1996 announced that natural gas is the No.1 alternative because:

1. Natural gas has excellent combustion properties,

2. Natural gas is a safe fuel (lighter than air, high ignition temperature),

3. Natural gas is a clean fuel (no sulphur, no lead, no particles, little NOx, CO and HC).

4. Natural gas has abundant reserves, wide spread over the globe.

5. Natural gas is a strategic fuel,

6. Natural gas is cheap if we exclude taxes.

Natural Gas Vehicle (NGV) Basics

Natural gas used in vehicles is no different than natural gas used in residential or

commercial markets, except that it is compressed to high pressures for storage purposes.

Compressed natural gas (CNG) is gas compressed to pressure generally ranging from 200 to 259

bar (20.7Mpa to 25Mpa). At the dispenser, Natural Gas is delivered into vehicles either by

weight (in kilograms) or by Gasoline liter equivalents (GLE – an energy equivalent comparison

to gasoline) and carries an octane rating between 122 and 130.

There are many types of natural gas vehicles (NGV’s), including dedicated, Bifuel and

dual fuel models. There are distinguished by whether the engine runs only on natural gas

(dedicated), operates on either natural gas or gasoline (Bifuel), or simultaneously burns a

combination of both liquid fuel (such as Diesel or Petrol) and natural gas (dual fuel).

CNG is stored onboard a vehicle in several types of pressurized vessels that conform to

industry-recognized standards for installation (the NGV 2 standard in Canada & USA or OISD

Standard 226 for City Gas distribution in India)

If NGV’s and equipment are in sound condition, you can expect them to perform reliably

when they are well maintained by a trained technician and drivers are well informed and trained.

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Although conventional wisdom holds that natural gas engines should require fewer oil

changes and perhaps even less frequent scheduled maintenance because of less carbon build-up,

regular maintenance of the vehicle, engine and/or conversion system will ensure the superior

performance of the NGV versus its gasoline and diesel counterparts.

A CNG fueling facility typically consists of a compressor, storage Cascades and a

dispenser system. Dispensers come in two types: fast fill, which delivers fuel at a rate

comparable to gasoline or diesel systems, and time fill, which fuels vehicles over a period of

time. The actual fueling of an NGV is similar to fueling with gasoline or diesel.

CNG Quality Control

An extensive quality control of the incoming Natural Gas for Refueling in the city of

New Delhi is done at the Mahipalpur CNG Station, which comes under the Lado Sarai

Control Room. A Gas Chromatograph monitors and records the quality of the Natural Gas at

all hours of the day all round the year. It measures quantitatively the %composition of various

components of the Natural Gas, which further helps in maintaining exact desirable proportions.

The incoming Gas from GAIL is odorless and therefore, a smelling agent (Ethyl

Mercaptin and Methyl Mercaptin) is mixed into the Gas at IGL’s Patparganj Plant. Where the

smelling agent is introduced at traceable quantities as the concentration magnifies when

compressed. A detailed functioning of the Gas Chromatograph is explained further.

Major contents of the Quality control are: %Composition of C1 - C6& above, Gross

Calorific Value, Net Calorific Value and specific volume.

As the Gas upon combustion releases water in the form of vapor, this water vapor

releases more heat in the process of condensation. This heat when added to the Gross Calorific

value (GCV) of the fuel is known as the Net Calorific Value (NCV).

Specific Volume is the volume of Gas occupied by 1 Kg of Gas at Standard Temperature

and Pressure (STP).

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Gas Chromatograph (GC)

In a Gas Chromatogram (GC) Analysis, 0.1-10µL (micro liter) of a mixture of

compounds is injected into a heated Injector, where all of the compounds vaporize. A gentle

stream of the Carrier Gas, Helium (He) moves the entire mixture onto the Collumn, the

corresponds of the mixture separate as they pass through the column. The process can be

considered as an exceptionally good Fractional distillation using a superb fractionating column.

Figure 1: Schematic representation of the components of a GC

The Process

The separated compounds pass from the column into a detector that produces an

electrical signal proportional to the amount of compound passing through the detector. A

recorder provides a graph. The Gas Chromatogram is plotted against the detector Signal versus

Retention time. The Gas chromatogram shows a peak for each compound in the mixture. The

retention time can be measured from the Chromatogram. An Integrator measures the areas under

the peaks in the Gas Chromatogram.

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The Chromatogram

A chromatogram consists of a base line and a number of peaks. The area of a peak allows

quantitative determinations. Starting point of a chromatogram is the time of injection of a

dissolved sample. The time interval between a peak and the point of injection is called retention

time tR. A component can be identified by its retention time (qualitative determination).

The retention time is the sum of the residence time of a solute in the mobile phase (t0) and

in the stationary phase (tR' = net retention time); t0 is also known as dead time. It is the time

required by a component to migrate through the chromatographic system without any interaction

with the stationary phase (also called air or gas peak).

For a given, the area under its peak on the chromatogram is proportional to the amount of

the compound in the sample. Direct comparison of peak areas for different compounds is

unreliable because detectors do not have the same sensitivity to all compounds. For this

reason, a sample of the Natural Gas is maintained in the GC. The Area under the

chromatogram is then compared to that of the sample, and the result is recorded.

Figure 2 detectors used in Gas Chromatography

Thermal Conductivity Detector (TCD)

Flame Ionization Detector (FID)

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Figure 4: Schematic Chromatogram

COMPONENTS Jan Feb Mar Apr May Jun July

C1 92.7464 92.4233 94.102 91.7059 90.8413 88.64 91.4763

C2 4.0807 4.2759 4.6296 4.3309 4.4206 5.2094 4.3462

C3 0.8629 1.0646 0.7279 0.8726 0.6122 1.3443 0.7145

I-C4 0.1161 0.1541 0.1227 0.0991 0.0232 0.1589 0.058

N-C4 0.1641 0.2225 0.1657 0.1368 0.0003 0.1705 0.0626

N2 0.1745 0.2326 0.1659 0.1904 0.1045 0.0983 0.1364

CO2 1.8521 1.627 0.0793 2.6596 4.0063 4.2942 3.2024

Neo-C5 0 0 0 0 0 0

I-C5 0.0029 0 0.0053 0.0037 0.0008 0.0297 0.0023

N-C5 0 0 0.0015 0.001 0.0007 0.0256 0.0013

C6+ 0.0003 0.0001 0 0 0 0.0291 0

GCV 9294.51 9368.78 9476.66 9230.251 9043.145 9257.759 9142.276

SG 0.6059 0.6082 0.5903 0.6145 0.6219 0.6419 0.6164

Table 1: GC data Mahipalpur Plant (Period: Jan-July2011)

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C1: Methane

C2: Ethane

C3: Propane

I-C4: Iso-Butane

N-C4: Normal Butane

N2: DiNitrogen

CO2: Carbon Dioxide

Neo-C5: Neo Pentane

I-C5: Iso Pentane

N-C5: Normal Pentane

C6+: Higher Alkanes

GCV: Gross Calorific Value (J/mol)

SG: Specific Gravity (m3/Kg)

Standard Reaction of HC combustion:

………………….…ΔHr = Gross Calorific Value

Limitations:

Only compounds with vapor pressures exceeding about 10–10

torr can be analyzed by gas

chromatography mass spectrometry (GC-MS). Many compounds with lower pressures can be

analyzed if they are chemically obtained (for example, as trimethylsilyl ethers). Determining

positional substitution on aromatic rings is often difficult. Certain isomeric compounds cannot be

distinguished by mass spectrometry (for example, naphthalene versus azulene), but they can

often be separated chromatographically.

Accuracy:

Qualitative accuracy is restricted by the general limitations cited above. Quantitative

accuracy is controlled by the overall analytical method calibration. Using isotopic internal

standards, accuracy of ±20% relative standard deviation is typical.

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Difference between Gross Calorific Value and Net Calorific Value:

The Water produced in the combustion reaction is in the gaseous state. This water when

condensed to liquid state at ambient temperatures in the cylinder releases the Latent heat of

Condensation which unlike the Gross Calorific Value is released from the exhaust when it

interacts with air at ambient temperature. This additional energy is not used for the expansive

working within the piston cylinder and therefore is not accounted for in the actual Calorific

Value of the gas mixture. The Net Calorific Value is what we read in instruments and we

subtract the known value of Latent heat of condensation of steam at given conditions to obtain

the Gross Calorific Value.

Net Calorific Value (NCV) – Latent heat (condensation) = Gross Calorific Value (GCV)

CNG Refueling Station

A CNG station is a site consisting of interconnected equipment, which is designed to

compress Natural Gas to a high pressure and either store the CNG (if the site is equipped with

storage) or dispense it directly to a natural gas vehicle for refueling.

A CNG station typically consists of one or more compressor packages to compress the

Natural Gas, and several additional systems, which include Cascade storage systems, PLC based

controls system such as a priority controller panel, a temperature/pressure compensation panel, a

buffer panel, gas dryers, fast refueling (CAR dispensers) and time refueling (BUS) dispensing

units.

The Station includes separate areas for Compression, Storage and Dispensing. It includes

Air compressor pipes, Water pipelines etc. It also includes provisions for safety against Fire or

Leakage. The provisions include Carbon dioxide (CO2) Cylinders; Dry Chemical Powder (DCP)

cylinders etc.

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CNG Distribution Network

Type of stations at IGL

Mother station: It’s a station where a direct gas line received and SCM capacity of

compressors installed there is more than 1200 SCM and LCV is also filled.

Online station: It’s a station where online gas line is received from GAIL but the

capacity is up to or below 1200 SCM. Cascades filling are also there.

Daughter booster station: It’s a station where compressors are not installed and gas is

being compressed by means of a device named booster.

Daughter station: It’s a station where gas is not compressed at the station itself and is

filled direct from the LCV.

CNG

Compressor

Storage

Cascade

Dispenser

CNG Vehicle

CNG

Compressor

Storage

Cascade

Dispenser

CNG Vehicle Mobile

Cascade

Mobile

Cascade

Mobile

Cascade

Mobile

Cascade

Booster

Compressor

Dispenser Dispenser

CNG Vehicle CNG Vehicle

DAUGHTER

BOOSTER

STATION

DAUGHTER

STATION

MOTHER

STATION

ON-LINE

STATION

Main line ~18-20 bar

~18-20 bar

~250 bar

~200 bar

~18-20 bar

~200 bar

~200 bar

~200 bar

~250 bar

~200 bar

Figure 5: Schematic diagram of CNG distribution at IGL

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CNG Station Basics

Key CNG Refueling Station Equipment:

Gas Dryer (inlet or outlet)

Compressor Package System (bare shaft compressor, inter-stage cooler, piping,

separators)

- Driver (electric motor or gas engine)

- Low pressure inlet train

- High pressure outlet system

- Canopy or housing (weather protection/noise attenuation)

Cascade Storage System

Priority Control Panel

Car Dispenser

Dispenser (single or double hose, metering or non-metering, trickle, fast fill)

Compression System

Natural gas is usually transported to the CNG station site from the main Gas Pipeline

provided by GAS AUTHORITY OF INDIA LIMITED (GAIL). This gas can range in pressure

from as low as 12 bar (gauge pressure above atmospheric), to as high as 35 bar/ 3.45 Mpa or

higher. In any case, it is still too low of a pressure for use in vehicle storage systems.

For this reason, the gas must be compressed. However, prior to compressing the gas, the

incoming gas may need to be conditioned further, so as not to damage the compression

equipment or downstream systems. For example, if the gas is “wet”(has an unusually high

concentration of evaporated water), then the gas will first pass through a dryer, if the Sulphur

contents in the gas is higher, it also should be removed. This is a large vessel, surrounded by

related components, which removes water from the gas stream using a “desiccant” material.

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Once the gas is properly conditioned as required, it then enters the compressor. The

compressor is typically the largest and most complex piece of equipment in the entire refueling

station. It raises the pressure of the natural gas to 250 bar (25Mpa), or higher, using a number of

separate stages, which increase the gas pressure in increments.

The Compressors are typically reciprocating compressors. These are driven in a rotational

manner, with the compressor translating this rotational force into a Piston/Cylinder combination.

Much like the reverse of an engine, a compressor uses a series of valves to move the gas

into each cylinder, compress it with a Piston, and then discharge in into the next stage at an

increased pressure. The cylinder configurations can either be a “W” or “V” shape, or horizontally

opposed.

Metering Skid

The first Equipment on the Main Inlet piping is the Metering Skid. It helps monitor

precise Station Inlet GAS characteristics as per requirement up to compressors which helps study

gas loses over compression etc. Flow mater readings help CNG Station Marketing and Sales

Department tally Station reconciliation with respect to sales and also IGL gas reconciliation with

GAIL (India) Pvt. Ltd.

Main Functions:

Pressure regulation.

Gas filtration.

Preventing Pilferage

Precise metering

Cross-Checking of metering

Emergency shut-down of station through Main Isolation Valve

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Major Components

Suction Line Filter

The Suction Line filter includes protection from moisture, inorganic and organic acid

resulting from burnout or chemical changes in the system. It also clears away combustible

dust, which may be introduced through mechanical work done over the Pipeline. It has a 5µm

Filter for such unwanted particles.

Slam shut-off valve

The Slam shut off valve is used in Metering skid for shut off line in case of emergency

when line pressure is above 23 kg/cm2 or below 13kg/cm

2. It is a Butterfly Valve which is

also called the Main Isolation Valve which may be used to cut-off the whole station from the

Main Pipeline.

Pressure regulating Valve

It regulates the pressure of gas in flow line according to adjustable limit.

Mass Flow meter

Mass flow meter is used in flow line to continuously monitor the input mass flow of Gas. It

uses a Coriolis Type of mechanism for reading Flow rate.

Pressure and Temperature transmitter

Pressure transmitter and Temperature transmitter is used to sense Pressure and Temperature

in line pressure to Flow Boss. A special Differential Pressure meter is installed across the

Filter, which indicates amount of choking residue on the filter as the pressure drop across it.

A Differential Pressure of 1 bar or above means that the filter requires cleaning.

Flow boss (flow computer)

Each characteristic data such as inlet pressure, temperature, Mass Flow etc. for the Gas at

Inlet is stored in flow boss to log the data in computer.

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Compressor drive

The Compressor can be driven either by an Electric Motor, or by a Natural Gas engine.

For an electric motor drive, an electronic device called a starter or soft start applies power to the

motor when the compressor is required to turn on. The motor shaft is coupled to the compressor

shaft either directly, or by means of a belt drive. Typically, larger compressors are direct-driven.

A compressor package also has a great deal of support equipment associated with the

package. Mechanically, the compressor requires a lubricating oil supply to lubricate the

cylinders, pistons, and other moving parts. It also requires a means to remove from the gas

supply oil that is introduced through lubrication.

This typically involves a system of filters and separators. Filters are typically placed at

the inlet and the discharge of the compressor itself, while in-line gas separators are placed

between the stages of compression. Separators spin the gas in a circular motion to use

centrifugal force to condense any liquid out of the gas stream. This results in a collection of

condensates, typically water and oil, which must be periodically removed from the separator

vessels. This is typically done automatically in the packages, with collection in the large

recovery tank(s) and later automatically drained into one of the beams in the skid case.

F

I

L

T

E

R

Figure 6 Schematic diagram of the metering skid

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Compressor: Dresser Rand

• Maximum Driver HP 250 (186 kW)

• Standard Stroke 7 inch (178 mm)

• Crankshaft Diameter 3.75 inch (95 mm)

• Cylinder Diameter (LP) 4.00 inches

• Cylinder Diameter (HP) 3.25 inches

• Main Bearing Length 3.75 inch (95 mm)

• Piston Rod Diameter (LP) 1.5 inch (38 mm)

• Piston Rod Diameter (HP) 2.25 inch (57.15mm)

• Speed 570 (rpm)

Materials:-

• Frame Cast Iron

• Crankshaft Forged Steel

• Connecting Rod Forged Steel

• Crosshead Aluminum

• Main Bearing Aluminum

• Crankpin Bearing Aluminum

• Pin Bushing Bronze

o Crosshead Pin Steel Alloy

• Design parameters:-

o Suction pressure 14-22 bar

o Inter stage compression ratio Suction Discharge

Ist Stage: 3 14-19 bar 45-60 bar

IInd Stage 2 45-60 bar 120-130 bar

IIIrd Stage 2 120-130 bar 220-250 bar

• Compressor Flow rate:- 1200 SCMH (916 Kg/Hr) at ideal condition

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Cooling System

Compressors generate heat as a natural byproduct of compression. For this reason, they

must be cooled. IGL generally has only air-cooled compressors, which means they employ

forced air-cooling of the compressor and/or gas stream, instead of water cooling like one would

find in a car engine. Some compressor blocks are self-cooling, incorporating a fan onto their

main drive shaft, which forces air over the compressor block and over the compressed gas lines.

Other blocks require separate heat exchangers, which cool the gas after each stage using a

separate fan.

These Heat exchangers (Inter Coolers) are Shell and Tube with Fins, with multiple passes

in order to result in the desired Temperatures at inlet and outlet for each Stage.

Recovery system

Another important system is the blow down recovery system. This system, which

includes the recovery tanks and various automated valves, captures the gas from the compression

system when the machines are shutoff, and maintains a closed loop system by containing and

recycling this gas. It also permits the compressor to start and stop “unloaded”, or without

compressing gas, by re-circulating the gas within the compressor on start-up, and on shut-down.

The majority of this gas is captured in the recovery tanks.

The compression equipment also required a great deal of electronic and electrical control,

as most skids are automated to a high degree. This means that they must have enough

intelligence to turn themselves on, shut themselves off appropriately, and do it all safely, while

watching for possible faults. This is generally accomplished by the electronic controls system

on–board each skid. The vessel is called a Blow Down Vessel (BDV).

A Knock out drum of 900 litres is provided at suction, supply CNG to the compressor

through flexible hose to suction collector and first stage cylinder. BDV also acts as a condensate

collecting bottle. All the condensate and oil are drained into the BDV.

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Gas Flow within Compressor

Condensate

1st

Stage PT101 PCV108

INTER COOLER

PT102 PT103

AFTER COOLER

PRIORITY

PANEL

PT104

BDV

(Blow

Down

Vessel)

PRV

PT106

INTER COOLER

Inlet

2nd

Stage

3rd

Stage

Figure 7: Schematic layout of Compressor system

Natural Gas

Package Boundary

Condenate (Water + oil)

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Mechanism of Compression

Compression

Expulsion of gas

Initial condition

Suction stroke

Expansion of

residual gas

Clearance

volume

Figure 8: PV diagram for Single Stage Reciprocating compressor

Figure 9 PV diagram for Multi Stage Reciprocating compressor

Shaded area

represents

net saving in

energy

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General Physical Parameters

• 1st stage suction pressure (Kg/cm2) = 14.95

• 1st stage discharge pressure (Kg/cm2) = 43

• 2nd stage discharge pressure (Kg/cm2) = 79.49

• 3rd stage discharge pressure (Kg/cm2) = 146

• 1st stage suction temperature (oC) = 37

• 1st stage discharge temperature (oC) = 125

• 2nd stage discharge temperature (oC) = 102

• 3rd stage discharge temperature (oC ) = 96

• Gas temperature after cooler (oC) = 52

• Lube oil pressure (Kg/cm2 ) = 1.02

• Flow meter totalizer reading suction (Kg).

• Flow meter totalizer reading discharge (Kg)

Compressor start preconditions

Tag name Tag description

PT-101 1ST

Stage suction pressure.

PT-102 2nd

Stage suction pressure.

PT-103 3rd

Stage suction pressure

PT-104 3rd

Stage discharge pressure.

PT-105 Engine fuel gas pressure.

PT-106 Blow down vessel pressure

PT-401 Engine starting air pressure.

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GD-501 Gas detector

GD-502 Gas detector

FD- 501 Flame detector

FD-502 Flame detector

TE-101 1st Stage gas suction temperature

TE-102 1st Stage gas discharge temperature

TE-104 2nd

Stage gas discharge temperature

TE-106 3rd

Stage gas discharge temperature

TE202 Engine Jacket Temperature (oC)

TE-301 Engine lubes oil temperature

TE-108 Engine exhausts gas temperature

TE-208 Compressor cooling oil header Temperature

LSL-201 CW surge tank level low

SSHH-101 Engine over speed contact

Emergency stop Emergency stop push button

SOV-101 ON Drain solenoid valve ON

PT-301 Engine lubes oil pressure

PT-302 Compressor lubes system oil Pressure

TE-107 Engine inlet manifold temperature

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SOV-110 PT-110 High Bank

Car cascade

SOV-111 PT-111 Medium Bank

Car Cascade

SOV-112 PT-112 Low bank

Car cascade

SOV-113 PT-113 High bank car

dispenser

SOV-112 PT-112 Bus

Cascade

SOV-112 PT-112 Bus Cascade

SOV-112 PT-112 Mobile

bank

SOV-117 Medium bank

Car Dispenser

SOV-118 Medium bank

Car Dispenser

C

N

G

Priority panel

The priority panel consists of a priority valves and non return valves, so arranged that

intended use of providing priority to vehicles is achieved. The priority panel is connected to

discharge of compressor at one end and is connected in parallel to cascade (storage) and

dispenser at other end. If there are no vehicles for gas filling, then priority valve directs the gas

flow to cascade.

NRV: Non Return valve

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LCV Priority Routing

The Mobile Cascade Vehicles, also known as LCV, are Flatbed trucks on which a

Cascade has been securely tied. These contain about 2200-2400 Liters of Natural Gas at 250 bar.

These are filled at Mother Stations and transported to Various Daughter and Daughter Booster

stations under each Control Room. This movement of LCVs around the city has been outsourced

to various Transport Contractors, who charge on per-km basis. The Job of priority routing arises

in order to minimize the Total number of Kilometers that have to be paid for, while still

providing Gas to the Required Daughter and Daughter Booster Stations.

Such a Routing is done every time the Contractor revises the Km-Data chart and/or a new

Station comes up under a Control Room. This form of Assignment is a Linear Programming

Problem (LPP), Transportation Problem. The Following Figures Explain the Priority Routing

under Jail Road control room.

Figure 10: Suggested Priority routing Chart, data in Kms

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The Priority Routing involves more parameters than assumed, such as licensing issues

and capacity considerations. Jail Road control room consists of 19 LCVs. 13 of which are

contracted to Chowdhary transport and 6 through Orient Transport. There exist two Daughter

and six Daughter stations under this control room and therefore a well planned and executed

priority route results in considerable monetary and energy savings.

Figure 11: Existing Priority chart for Jail Rd Control room

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Hazardous Area Classification of a CNG Station

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Hazardous Area Classification of a CNG Station

OISD, OIL INDUSTRY SAFETY DIRECTORATE (Government of India, Ministry of

Petroleum and Natural Gas) issues a Safety Standard for the operation and distribution of city

Gas.

A major aspect of understanding Hazardous Areas is to classify them on the basis of the

surroundings and the kind of materials present. Such classification can be found in the National

Electric Code (NEC), which is a standard for classifying Dangerous locations on operational and

breakdown basis. It also includes dangers from all sorts of materials which may be present such

as foam, plastics, combustible dust, etc.

30

The Cascade cylinder storage area and the compressor area have been classified as Class

I - Division I as these handle high pressure Natural Gas (Group I), which is present in the

atmosphere at all times of normal functioning and require acute attention in case of a failure or

breakdown.

The dispensing area has been classified as one which is the most prone to Hazards as vent

gas is always present in considerable quantities, under normal functioning. Under an event of

mechanical failures in the tubing etc. this area would be highly dangerous as the General Public

accesses this area for CNG refilling.

The Filtration and Metering skid Area is classified as Class II – Division II –Group E,F,G

as combustible dusts of all composition is present in the incoming Natural Gas and proves to be

harmful in case of maintenance operations.

31

Data for Pressure drop in piping at Suction

Buckhardt Compressor date: 25th June2011

Engine gas Flow: 24.8888889 Kg/hr

Engine Inlet Suction Flow meter: 670.555556 Kg/hr

(ρ) Density at 15.07 bar, 29.07oC: 9.483 (kg/m3)

Volumetric flow rate: 70.71133 (m3/hr)

(Q) Volumetric flow rate: 0.01964 (m3/s)

(D) Diameter of pipe (2”): 0.0508 (m)

(v) Velocity: 9.695929 (m/s)

(T) First stage Suction temperature: 29.07oC

(µ) Viscosity of gas at 15.07 bar, 29.07oC: 1.182*10-5 (kg/m.sec)

(k) Kinematic viscosity of gas: 1.25*10-6 (m2/sec)

(Nre) Reynold’s number: 395194.37

Formulae used

Volumetric flow rate: (Mass flow rate)/Density

Flow (m3/hr)/3600 : Flow(m3/s)

Velocity of Flow: Volumetric flow rate/Cross sectional area of Flow (πD2/4)

Kinematic Viscosity: Dynamic Viscosity/density

Reynolds number: (Diameter*Velocity)/kinematic Viscosity

32

33

34

35

Assumptions for Calculations

Natural Gas is assumed to be 100% Methane, and properties of Methane at Low pressure

and High Pressures assumed to be properties of Natural gas at the given Pressures and

Temperatures.

Moody diagram for coefficient of friction has been linearly interpolated between known

values to obtain an approximate coefficient for a given Reynolds number and roughness

factor.

Pressure regulation Valves (PRVs) etc. equipment at the metering Skid have been

assumed to result in zero pressure loss.

36

Figure 12: Moody diagram (Ref: College of Nautical Sciences, Glasgow)

37

Comparative Data for Pressure Drop in Tubing

Mass Flow rate: 300 Kg/hr

Pressure: 250 bar

Thermodynamic properties of Gas at 250 bar and 21oC

Density (ρ): 192.46225841658 Kg/m3

Viscosity (µ): 2.38456076692404*10-5

N.s/m2

Compressibility (Z): 0.852039803268427

Kinematic Viscosity (ν): 1.23897578*10-7

m2/s

Volumetric Flow Rate: 1.558747m3/hr

Volumetric Flow Rate (Q): 4.32985278*10-4

m3/s

Tubing data: 3/4" Tubing 1” Tubing 5/4” Tubing

Outer Diameter (O.D.) 1.9cm 2.54cm 3.175cm

Thickness* (from Table 1) 0.095” 0.12” 0.156”

Internal Diameter (D) 0.014174m 0.019304m 0.023825m

Roughness (k) (Table 2) 0.00008m 0.00008m 0.00008m

Roughness Factor(k/D) 0.00564 0.00414 0.00335

Velocity of Gas (v) 2.74409026 m/s 1.47941028 m/s 0.971219582 m/s

Reynold’s Number (Nre) 3.13837927*105 2.30501165*10

5 1.86761573*10

5

Coefficient of Friction(λ)

(Fig)

0.032 0.029 0.028

Length of Tubing (L) 10 m 10 m 10 m

Pressure loss (ΔP) using

Formulae

16364.1139 Pa 3164.05144 Pa 1067.13748 Pa

Pressure Loss (ΔP) 0.16364.1139 bar 0.0316405144 bar 0.0106713748 bar

38

Table for Tubing Data (Parker Hannifin Corp.)

*Thickness of tubing required to handle Maximum allowable Working Pressure assumed

to be the next higher available value of pressure above 300bar

Table 2: Maximum Allowable Working Pressure for Tubing

39

Roughness of Materials

Aluminium, drawn/pressed New 0.0013 - 0.0015 mm

Aluminium, drawn/pressed Used to 0.03 mm

Brass, drawn/pressed New 0.0013 - 0.0014 mm

Brass, drawn/pressed Used to 0.03 mm

Cast iron average city severage 1.2 mm

Cast iron Incrusted to 3.0 mm

Cast iron new, bituminized 0.10 - 0.13 mm

Cast iron new, with skin 0.2 - 0.6 mm

Cast iron operating several years, cleaned 1.5 mm

Cast iron slightly rusty 1.0 - 1.5 mm

Copper, drawn/pressed New 0.0013 - 0.0015 mm

Copper, drawn/pressed Used to 0.03 mm

Glass, drawn/pressed New 0.0013 - 0.0015 mm

Glass, drawn/pressed Used to 0.03 mm

Steel after long operation cleaned 0.15 - 0.20 mm

Steel homogeneous corrosion pits 0.15 mm

Steel intensely incrusted 2.0 - 4.0 mm

Steel slightly rusty and incrusted 0.15 - 0.40 mm

Steel, longitudinal welded new, bituminized 0.01 - 0.05 mm

Steel, longitudinal welded new, galvanized 0.008 mm

Steel, longitudinal welded new, rolling skin 0.04 - 0.1 mm

Steel, weldless new, comm.size galvanized 0.10 - 0.16 mm

Steel, weldless new, neatly galvanized 0.07 - 0.10 mm

Steel, weldless new, pickled 0.03 - 0.04 mm

Steel, weldless new, rolling skin 0.02 - 0.06 mm

Steel, weldless new, unpickled 0.03 - 0.06 mm

Table 3 Roughness of Materials

40

Grades of Steel Used:

The Society of Automotive Engineers (SAE) designates SAE steel grades. These are four

digit numbers which represent chemical composition standards for steel specifications.

The American Iron and Steel Institute (AISI) originally started a very similar system. Over time

they used the same numbers to refer to the same alloy, but the AISI system used a letter prefix to

denote the steelmaking process.

Carbon and alloy steel

Carbon steels and alloy steels are designated by a four digit number, where the first digit

indicates the main alloying element(s), the second digit indicates the secondary alloying

element(s), and the last two digits indicate the amount of carbon, in hundredths of a percent by

weight. For example, a 1060steel is a plain-carbon steel containing 0.60 wt% C.

Major classifications of Steel

SAE designation Type

1xxx Carbon steels

2xxx Nickel steels

3xxx Nickel-chromium steels

4xxx Molybdenum steels

5xxx Chromium steels

6xxx Chromium-vanadium steels

7xxx Tungsten steels

8xxx Nickel-chromium-vanadium steels

9xxx Silicon-manganese steels

SAE designation Type

Carbon steels

10xx Plain carbon (Mn 1.00% max)

11xx Resulphurized

12xx Resulphurized and Rephosphorized

15xx Plain carbon (Mn 1.00% to 1.65%)

41

Manganese steels

13xx Mn 1.75%

Nickel steels

23xx Ni 3.50%

25xx Ni 5.00%

Nickel-chromium steels

31xx Ni 1.25%, Cr 0.65% or 0.80%

32xx Ni 1.25%, Cr 1.07%

33xx Ni 3.50%, Cr 1.50% or 1.57%

34xx Ni 3.00%, Cr 0.77%

Nickel-chromium-molybdenum steels

43xx Cr 0.50-0.95%, Mo 0.12-0.30%

47xx Ni 1.82%, Cr 0.50-0.80%, Mo 0.25%

81xx Ni 1.82%, Cr 0.50%, Mo 0.12%

V 0.03% min

81Bxx Ni 1.05%, Cr 0.45%, Mo 0.20%

86xx Ni 0.30%, Cr 0.40%, Mo 0.12%

87xx Ni 0.30%, Cr 0.45%, Mo 0.12%

88xx Ni 0.55%, Cr 0.50%, Mo 0.20%

93xx Ni 0.55%, Cr 0.50%, Mo 0.25%

94xx Ni 0.55%, Cr 0.50%, Mo 0.35%

97xx Ni 3.25%, Cr 1.20%, Mo 0.12%

98xx Ni 0.45%, Cr 0.40%, Mo 0.12%

Nickel

molybdenum Ni 0.55%, Cr 0.20%, Mo 0.20%

46xx Ni 1.00%, Cr 0.80%, Mo 0.25%

Chromium steels Ni 0.85% or 1.82%, Mo 0.20% or 0.25%

50xx Ni 3.50%, Mo 0.25%

50Bxx Cr 0.27% or 0.40% or 0.50% or 0.65%

51xx Cr 0.50%, C 1.00% min

51xxx Cr 0.28% or 0.50%

51Bxx Cr 0.80%, 0.87%, 0.92%, 1.00%, 1.05%

52xxx Cr 1.02%, C 1.00% min

42

Stainless Steel SS316—

The second most common grade (after SS304); for food and surgical stainless steel uses;

alloy addition of molybdenum prevents specific forms of corrosion. It is also known as marine

grade stainless steel due to its increased resistance to chloride corrosion compared to type SS304.

SS316 is often used for building nuclear reprocessing plants. SS316L is an extra low carbon

grade of SS316, generally used in stainless steel watches and marine applications, as well

exclusively in the fabrication of reactor pressure vessels for boiling water reactors, due to its high

resistance to corrosion. Also referred to as "A4" in accordance with ISO 3506, SS316Ti includes

titanium for heat resistance, therefore it is used in flexible chimney liners.

43

An example of how the Cascade System Utilizes a Three Stage Storage

Bank to Provide a More Efficient System than the Single Control Volume

Storage Supply

An article published by RP publishing written by Ralph O. Dowling of C.P.

Industries is summarized in this section to better describe the cascade system. The

cascade system as mentioned earlier is a more efficient system than the single

control volume storage supply. A brief description of how the cascade operates will

be described in the following paragraphs. An understanding of the effects of

compression on natural gas is the first step in understanding the cascade system.

44

Table 3 illustrates how Natural Gas is affected when compressed into the same volume as occupied by 1m3 of water. It

gives the amount of natural Gas in standard cubic metres(scm) that would occupy 1m3 Volume at a given pressure.

Table 4: Pressure - scm Natural Gas filled per Unit Volume

45

Storage System for Fast Fill: CASCADE

A cascade system is comprised of three banks (low, medium, high), which are

high pressure storage vessels. The whole cascade system holds about 891.96 scm of

Natural Gas at 250bar. These are deployed in two different configurations: 40 cylinder

of 75 Ltr capacity and 50 cylinders of 60 Ltr capacity.

Considering 40 X 75 liter configuration, each of the vessels has a water volume

of 0.075 m3, which would be 3 m3 total water volume. Banking cascade storage vessels

have a design pressure of 275 bar and a storage pressure of 250 bar. At 250 bar

each storage vessel will contain 22.299 scm of natural gas (0.075 m3* 297.32 scm / m3

water = 22.299 scm) at 210C. From Table3, at 250 bar, the volume of Natural Gas is

297.32 scm / m3 water. The Total Natural Gas contained in the system if all three

stages are at 250 bar and 21oC would be 891.96 scm (22.299 * 40).

The following assumptions have been made for the cascade sequence explanation:

Manual cascade system

1. Temperature remains constant

2. Each vehicle cylinder has a water volume of 65liters (0.065 m3)

3. The vehicle cylinder will contain 16.40 scm of natural gas at a pressure of

200bar

4. Each vehicle cylinder(s) is initially empty

5. No replenishment of the cascade bank during the refueling cycle

The liquid volume (empty) of the vehicle cylinders can be calculated by dividing

the specified capacity at 200bar (16.40 scm) by the amount of gas in scm (from Table 3)

contained in 1m3 liquid volume at 200bar. So the total water volume of the vehicle

cylinder would be 16.40 scm / (252.33 scm / m3) = 0.065 m3

46

Cascade as a Single Control Volume

The Cascade is first taken to be a single control Volume of 40 cylinders of 75

liter Water Capacity each. Total Capacity is 3000 (75*40) Water Liters at 250 bar.

The Available quantity of Natural Gas to be dispensed at 200 bar would be the

difference of scm of Natural gas held in the Cascade at 250 bar and at 200 bar from

Table3.

Amount of Natural Gas per m3 water at 250 bar: 297.32 scm

Amount of Natural Gas per m3 water at 200 bar: 252.33 scm

Water Capacity of cascade: 3m3

Available Qty of Natural Gas to dispense: (297.32-252.33)*3 = 134.97 scm

Number of Vehicle cylinders filled: (134.97/16.40) = 8.229

Therefore approximately Eight (8) vehicle cylinders can be completely filled at

200 bar from a 3000 water liter cascade at 250 bar without the compressor having to

recharge the cascade.

47

Cascade as a Banking System

The Cascade is now divided into separate Banks (Low-med-High) based on the

priority with which they fill the vehicle cylinder. The Ideal configuration is 50% of all

cylinders be deployed for Low Bank, 30% Medium bank, 20% High Bank

Out of 40 cylinders in the Cascade

Low bank cylinders: 25

Medium bank cylinders: 10

High Bank cylinders: 5

Now, assume that the First NGV is ready to be serviced. The first vehicle can be

completely filled from the low storage bank without having to switch to the next storage

bank. The low bank contains 557.475 (=22.299*25) scm of natural gas at 250 bar, after

the first vehicle is serviced, the low bank will contain 541.075 scm (557.475 – 16.40) of

natural gas at (541.075/1.875) = 288.573 scm / m3

From Table 3 interpolate 288.573 scm / m3 to find the pressure in low storage

bank after the first NGV has been filled (239.57 bar).

The Second vehicle is now ready for service. The next vehicle can also be filled

to the 200 bar level from the low bank. The medium bank will not have to be used yet.

The second vehicle will be filled from the low bank until the pressure in the low bank

and the NGV pressures equalize. The same mathematical process for the first NGV

example must be done for the second.

524.675 scm (541.075 -16.40) of Natural gas remains in Low Bank at

(524.675/1.875) 279.82 scm / m3. From Table3 interpolate 279.82 scm / m3 to find the

pressure in the low storage bank (229.24 bar).

48

After the Third vehicle is serviced, 508.275 scm (524.675-16.40) of Natural Gas

remains in Low Bank at (508.275/1.875) 271.08 scm / m3, which corresponds to

(218.90 bar) pressure.

After the Fourth vehicle is serviced, 491.875 scm (508.275-16.40) of Natural

Gas remains in Low Bank at (491.875/1.875) 262.33 scm / m3, which corresponds to

(210.28 bar) pressure.

After the Fifth vehicle is serviced,475.475 scm (491.875-16.40) of Natural Gas

remains in Low Bank at (475.475/1.875) 253.58 scm / m3, which corresponds to

(201.67 bar) pressure.

The Sixth vehicle cannot be filled to the 200 bar level from the low bank. The

medium bank will now have to be used to top off the vehicle. The sixth vehicle will

initially be filled from the low bank until the pressure in the low bank and the NGV

pressures equalize. For that, we find the equalization pressure of the Low Bank with the

NGV cylinder, which is the pressure corresponding to

(Available quantity of gas) / (Volume of Low Bank + Volume of NGV cylinder)

= 475.475 / (1.875+0.065) scm gas/m3

= 245.09 scm gas/m3, which from Table3 corresponds to 193.05 bar pressure.

Since the low storage bank and the NGV are equalized, the NGV cylinder(s) now

contain a pressure of 193.05 bar (< 200 bar), the NGV must be topped off by the

medium storage bank to achieve the desired 200 bar fill level. The low bank now

contains 459.543 scm (245.09 scm/m3 * 1.875m3) of natural gas. The vehicle now

contains 15.93 scm of natural gas (0.065m3 * 245.09 scm / m3)

The medium storage bank must provide 0.47 scm (16.40 scm – 15.93 scm) of

natural gas to top off NGV number 6.

The Medium Bank contains 222.99 scm (22.299*10) of Natural Gas. The same

mathematical process as before must be compiled to determine the remaining pressure.

49

(222.99-0.47) / 0.75 m3 = 296.693 scm / m3

Using Table3, interpolate 296.693 scm / m3 to determine the total pressure remaining in

the Medium storage Bank (248.21 bar).

This method of calculating total volume and total pressure remaining can be

applied to fill process from a cascade system for Sixteen (16) NGVs. The first Sixteen

vehicles can be filled from the Low and Medium storage banks only with the Low

storing bank containing (326.85 scm at 136.16 bar) and the Medium storage bank

containing (191.150 scm at 201.67 bar) after the Sixteenth NGV has been filled.

NGV number 17 will have to be filled from the low, medium, and high storage

banks. The Seventeenth vehicle will first equalize pressure with Low storage bank

(132.71 bar) 326.85 scm / (1.875 + 0.065) m3 = 168.479 scm / m3

Through interpolation using Table3 the equalization pressure would be

132.71 bar.

After an initial fill from the Low storage bank, 10.95 scm of natural gas would be

contained in the NGV cylinder (0.065 m3 * 168.479 scm / m3).

NGV number 17 will now equalize pressure with the Medium storage bank

(196.50 bar). With 191.150 scm remaining in the Medium storage bank, the pressure in

the Medium storage bank and the NGV cylinder will equalize pressures.

(191.50 + 10.95) scm / (0.75 + 0.065) m3 = 247.97 scm / m3

Through interpolation using Table3 the equalization pressure would be

196.50 bar.

After the Low and Medium storage banks have gone through the equalization process,

the High storage bank must be utilized to top off the vehicle. NGV number 17 now

contains 16.11 scm (0.065 m3 * 247.97 scm / m3) of natural gas. With the NGV

containing 16.11 scm of natural gas, 0.29 scm (16.40 scm – 16.11 scm) must be added

to achieve the full fill level for NGV number 17. The high bank has a capacity of

111.495 scm (22.299*5) of Natural Gas. The remaining natural gas in the high bank

would be 111.205 scm (111.495 scm – 0.29 scm) at a pressure of 248.21 bar.

111.205 scm / 0.375 m3 = 296.54 scm / m3

50

Through interpolation, using Table3, the pressure remaining in the third storage

bank would be 248.21 bar.

If this process is continued, 25 NGVs can be filled before this cascade system

will need to be recharged by the compressor. If a single control volume storage

system were used instead of cascading, only 8 vehicles could be recharged before the

system would have to be replenished by the compressor. The Following Table

compares the efficiencies of the two systems.

System

Number of

vehicles

that can be

fueled

by the particular

system

Natual gas

capacity of

each NGV

(scm)

Natural gas

capacity (scm) of

system when

fully

charged

Efficiency of

system = (# of

vehicles * NG

capacity of each

NGV) / NG

capacity of the

system

Cascade

25

16.40

891.96

45.96%

Single Control Volume

8

16.40

891.96

14.71%

51

Suggestions for better safety and services

1. PNG

a. It is suggested to have Fuming Strips (perforated strips with smelling

agent) of mercaptin (Ethyl or methyl) to be supplied annually along with

the Gas consumption bill along with an instruction sheet which asks the

consumer to make each family member sniff the Strip and have an idea

about the smell which indicates them the presence of any form of leakage

in the supply system or flow meter. This would enable the consumer to be

able to detect / prevent a major Hazard.

2. CNG

a. I have strongly felt the need for the existence of regular Awareness

Camps at filling stations where consumers get to witness the immediate

remedial steps needed to be taken in case of an emergency within the car.

i. There should be Fuming Strips which replicate the smell of gas

leakage at the concentration at which it exists in the car.

ii. The camp should display protocols to be followed step by step in

case of an emergency’ depicting various complications which may

arise and ways to counteract them.

iii. The camp also shows the dangerously high pressures that exist in

various tubings within the car and how lethal such high pressures

can be. Citing common examples of the muzzle pressure inside an

AK47 making the audience experience a gauge pressure of 1bar on

their hands and explaining how dangerous a 200bar pressure

stream can be. Consumers also need to be repeatedly told about

common characteristic properties of the Natural Gas.

b. Every filling attendant must be given the authority to issue non-compliance

papers to CNG vehicles. Where any vehicle found to have dangerous /

worn out nozzle receivers(female) would be advised to get it changed

within a stipulated time period (suggested:1 Month). Failing which, CNG

52

will not be dispensed to the vehicle. This is in direct accordance towards

the safety of the filling attendants as dangerous recoils and snake sliding

in the hose occurs due to ineffective contact between the O-rings and the

female nozzle walls. The current inspection of cylinders at 5 years and

tubing at 1 year does not take into consideration normal daily wear and

faults which need immediate attention. The attendants have been

entrusted with such responsibilities as they witness hands-on the exact

state and seriousness of the issue.

3. CNG Filling Stations

a. UTILISING VENT GAS

i. Vent gas which is released into the atmosphere in order to break

the gas flow path in the dispenser nozzle so that it can be

disconnected from the vehicle should be utilized. A few suggested

uses of the gases (need of further experimentation required):

1. Producing electricity (the gas at approx 200bar can be

effectively used to produce energy by expansion over a

turbine and later combusted to produce a considerable

amount of energy to power the Flood lights on a filling

station.

2. The gas can be collected over an overhead container where

all the dispensers release their vent gas and this gas can be

later combusted to produce energy to power the

infrastructure around a CNG Filling station.

3. Implementation of SCADA, in order to effectively monitor

various units under a control room at once and result in swift

delivery of services and prompt servicing.

4. Quick licensing of compressor packages in order to result in

less effective kilometer usage on transport of LCV’s and

ease in meeting rising gas demands. (eg: licensing of

compressor package at Dwarka sec-20 filling station would

result in a net saving of 10 Km per LCV filling trip)

53

References

D. Rood, ”A practical guide to care, maintenance and troubleshooting of capillary Gas Chromatographic systems“, 2nd edition, Hüthig Verlag, Heidelberg, 1995

Degarmo, E. Paul; Black, J T.; Kohser, Ronald A. (2003). Materials and Processes in manufacturing (9th edition.). Wiley.

Jeffus, Larry F. (2002). Welding: Principles and Applications. Cengage Learning.

Dowling, Ralph O., .Cascade Basics, RP Publishing, 1993.

Moran, Michael J., Shapiro, Howard N., .Fundamentals of Engineering Thermodynamics., John Wiley and Sons Inc., New York, pp. 488-449, 1999.

Tubing manual and selection Guide, Product Catalogue: Parker Hannifinn Corporation, 2007

Ronald A. Hites Mass Spectrometry Gas Chromatography

National electric code (NEC), National Fire protection Association (NFPA), Batterymarch Park, Quincy, MA