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Graduate Report 2012-2013 Urban Infrastructure Planning and Management (CE-634) Domestic Gas Infrastructure Submitted By Malvika Jiashal (P12UP004) Faculty Adviser Dr. Krupesh A. Chauhan Post Graduate Section in Urban Planning Civil Engineering Department,
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Page 1: Domestic Gas Infrastructure

Graduate Report 2012-2013

Urban Infrastructure Planning and Management (CE-634)

Domestic Gas Infrastructure

Submitted By

Malvika Jiashal

(P12UP004)

Faculty Adviser

Dr. Krupesh A. Chauhan

Post Graduate Section in Urban Planning

Civil Engineering Department,

Page 2: Domestic Gas Infrastructure

Graduate Report 2012-2013

Contents

1. Introduction

2. Natural Gas

2.1. Forms of Natural Gas

2.2. Uses of Natural Gas

3. India: Oil And Gas & Infrastructure

3.1.History

3.2.Current Scenario

4. Gujarat: Present Status

5. City Gas Distribution

5.1. Infrastructure: City Gas Distribution Network

5.2. Various Stations Involved in the Network

5.3. How Gas is reached at Home?

5.4. Challenges in City Gas Distribution Network

6. Summary

References

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Graduate Report 2012-2013

1. Introduction

Natural gas is a vital component of the world's supply of energy. It is one of the cleanest,

safest, and most useful of all energy sources.

This graduate report is an attempt to give a brief view on Oil and gas Infrastructure of

India and Gujarat state. It also includes the details of Domestic gas infrastructure in urban

area.

2. Natural Gas

Natural Gas is colourless, shapeless, and odourless in its pure form. Natural gas is a

combustible mixture of hydrocarbon gases. While natural gas is formed primarily of methane,

it can also include ethane, propane, butane and pentane. The composition of natural gas can

vary widely, but below is a chart outlining the typical makeup of natural gas before it is

refined.

Table No.1: Typical Composition of Natural Gas

2.1. Forms of Natural Gas

a. Liquefied Natural Gas (LNG) – Natural Gas which has been liquefied at –

(Minus) 160 degree Centigrade. Natural Gas is liquefied to facilitate

transportation in large volumes in cryogenic tankers across sea.

b. Degasified Liquefied Natural Gas (RLNG) – LNG Re-gasified before

transporting it to consumers through Pipelines.

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Graduate Report 2012-2013

c. Compressed Natural gas, CNG - Natural Gas compressed to a pressure of 200-

250 kg/cm2 used as fuel for transportation. CNG decreases vehicular pollution on

the virtue of being cleaner fuel than liquid fuels.

d. Piped Natural gas, PNG - Natural Gas distributed through a pipeline network

that has safety valves to maintain the pressure, assuring safe, uninterrupted supply

to the domestic sector for cooking and heating / cooling applications.

2.2. Uses of Natural Gas

Following table the shows the uses of natural gas in various sectors:

Table No.2: Uses of Natural gas

Sector NATURAL GAS IS USED

POWER GENERATION As fuel for base load power plants

In combined cycle/co-generation power plants

Fertilizer Industry As feed stock in the production of ammonia and urea

Industrial As an under boiler fuel for raising steam

As fuel in furnaces and heating applications

Domestic and commercial For heating of spaces and water

For cooking

Automotive As a non-polluting fuel

Petrochemicals As the raw material from which a variety of chemical products

e.g. methanol, are derived

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Graduate Report 2012-2013

3. India: Oil and Gas & Infrastructure

India today has a vast network of underground pipelines being used for

transportation and distribution of natural gas. Big power plants, fertilizer plants & other

industrial enterprises are the main consumers of natural gas as on today. However, with

the increase in its popularity, it is now being used in the domestic sector as well as a fuel

in the automotive sector in the big metropolitan cities.

3.1. History

Indian oil and gas (O&G) sector marked its emergence way back in the late

19th century, when the oil was first struck at Digboi in Assam in 1889. Since then, the

sector has not seen back and has emerged as one of the core sectors for the country's

economy..

The country's exploration and production sector is majorly dominated by public

sector corporations wherein Oil and Natural Gas Corporation (ONGC) accounts for the

highest market share. Administrative structure of Natural gas sector is shown in the

following figure.

Fig: Natural gas sector Structure-India

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3.2. Current Scenario

India is world's fifth-largest energy consumer in the world; oil accounts for 30 per

cent of the total energy consumption. Buoyant economic growth is the main factor driving

the country's energy requirements. India's gas demand is approximately 11.2 per cent of

the total Asia Pacific regional demand. Several industries are increasing the usage of

natural gas in operations; this has boosted natural gas demand in India.

Gas consumption in India has grown at an annual rate of 10 percent from 2001 to

2011 despite insufficient pipeline infrastructure. Natural gas mainly serves as a substitute

for coal in electricity generation and with 45 percent of total use, the power sector is

currently the largest user of natural gas in India, according to a country specific energy

analysis from the US Energy Information Administration (EIA).

In 2011, India consumed 2.3 billion cubic feet of gas and projections from the

Indian Oil Ministry, see this figure increasing as demand is set to more than double in the

next five years. Of the country's 211GW of installed capacity, about 9 percent comes

from natural gas-fired plants. Coal retains the greatest share of the country's electricity

mix, accounting for some 57 percent of total installed capacity. India suffers from

widespread power outages however as both natural gas and coal-fired plants often shut

down due to insufficient fuel supply.

While the country was self-sufficient in natural gas until 2004, it currently does

not have sufficient natural gas infrastructure on the natural level to meet domestic

demand. As a result, LNG imports account for approximately 25 percent of total gas

demand. India began importing natural gas from Qatar in 2004 and was the world's sixth

largest LNG importer in 2011 according to data from PFC Energy. Indian companies use

both spot and long-term supply contracts to acquire natural gas

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Graduate Report 2012-2013

Fig: India Natural Gas Production and Consumption-2001-2011

Overall gas demand is also constrained due to insufficient pipeline infrastructure

as the country's current pipeline network primarily services the northwest region.

However, Reliance Gas Transport Infrastructure, owned by Reliance Industries has

brought the East-West gas pipeline online in 2009, which links the D6 gas field to the

north and west regions of the country. Other smaller companies such as Petronet LNG

and Gujarat State Petroleum Corporation (GSPC) are also considering building their own

pipelines. Gas Authority of India Limited (GAIL) has announced plans for an extension

to the Hazira- Bijapur- Jagdishpur pipeline and a line from the D6 field to parts of

southern India.

India also has plans to import natural gas from Turkmenistan via the proposed

Turkmenistan-Afghanistan-Pakistan-India pipeline. While, the countries have made some

progress moving forward, including agreement on a route, unified transit tariffs and

India's signing of supply and purchase agreements with Turkmenistan, significant

geopolitical and technical challenges to the project remain

4. Gujarat: Present Status

Gujarat, which accounts for more than one-third of the total natural gas consumed in

the country, Ministry of Petroleum & Natural Gas show that the total number of CNG

stations in the country was 724 as of November-end. Of these, Gujarat had 258 CNG

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Graduate Report 2012-2013

stations, the highest in the country. The number of CNG outlets in New Delhi stood at 239,

followed by Maharashtra with 164 CNG stations. Gujarat is the leader not only in CNG

stations, but also in PNG (Piped Natural Gas) connections and consumption.

Table No 3: Existing supply sources in the state

Sr. No. Supplier Source Volume of supply

(in MMSCMD)

1 ONGC

Onshore fields located near Ahmadabad

region & Ankleshwar / Surat region and

offshore (JV) fields in the Arabian Sea

(Western Offshore – including PMT

supplies)

20.00

2 GSPC/ Niko Resources Hazira gas field 00.60

3 Cairn CB-OS2 field in the Cambay basin 00.80

4 Petronet LNG Limited

(PLL) LNG from RasGas, Qatar 08.00

5 Shell, Hazira LNG spot cargoes 00.00

6 RIL KG D6 Gas 26.00

Total 55.40

Source: CRISIL Analysis

4.1. GPSC: Gujarat State Petroleum Company

Gujarat State Petroleum Company (GSPC) supplying gas to more than 3, 00,000

domestic customers, 1443 industrial customers and 1068 commercial customers. Through its

network of 120 CNG stations across Gujarat, GSPC Gas is fuelling more than 65,000 CNG

vehicles every day. Today, GSPC Gas has achieved remarkable sale of 4 MMSCMD of Gas,

which make it India's largest City Gas Distribution Company. The CSR initiative of GSPC

Group in Hazira has now turned out to be India's Largest City Gas Distribution Company.

From fuelling the kitchens of common people to energizing micro, small and medium

industries and from uninterrupted supply in hotels and hospitals to refuelling thousands of

CNG vehicles day and night, GSPC Gas is working 24 hours and 365 days for providing high

quality service with best HSE practice.

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CGD activity was started at Hazira (Surat) as a corporate social responsibility

initiative from Gujarat State Petroleum Company GSPC Group in 2002-03. An SPV was

conceptualized in 2005 and with one CNG station and few thousand of domestic connections;

GSPC Gas implemented its first CGD network in Hazira (Surat) in the year 2005. Currently

GSPC Gas is operating in more than 21 major town & city and more than 221 villages in the

state of Gujarat.

5. City gas Distribution

The four major sectors identified for the city gas distribution in India are:

a) Transport Sector

b) Domestic Sector

c) Commercial Sector

d) Industrial Sector

Domestic, Commercial and Industrial Sectors use Piped Natural Gas (PNG) where as the

Transport Sector use Compressed Natural Gas.

5.1. Infrastructure: City Gas Distribution Network

To take the gas to such end users who are located within the boundaries of a main

city, there’s a need to build up city gas distribution pipeline networks. Such networks have

already been developed in the cities of Delhi, Mumbai, Vadodara, Surat, Agra/Firozabad,

Kanpur and many more such networks are being planned in the near future. Looking at the

available infrastructure and layout in typical Indian cities, it becomes a difficult task to

build up such a city gas distribution networks in the absence of separate corridors for the

competing utilities. Depending upon the pressures, flow and economic criteria, these

networks can either be constructed using steel pipelines, polyethylene (PE) pipes or a

hybrid system of both PE & steel pipelines

i. The primary network: of steel pipelines provides the core backbone connecting

CGS to various DRS. The pressure levels for primary network are between 26 bar (g)

to 19 bar(g). While most of the industrial customers are not required to be supplied at

this pressure level, only a select few units have specific requirement for medium

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pressure delivery would be connected to through this network. The design of the

primary network is based on the demand forecast to be catered.

ii. Secondary network system: consisting of MDPE pipelines operates at pressure level

between 4 bar (g) to 1 bar (g). MDPE pipeline network is planned for cluster of

industrial, commercial or domestic units at low pressure. The secondary network is

normally developed with MDPE pipes.

Using the domestic / small commercial quantity and large commercial

quantity values, and additional information, including location of customers, pressure

requirements at major customers, availability of existing supply, and geographic

features, optimum method of supply is determined and the network is designed and

constructed accordingly.

The supply facilities include the following:-

i. High pressure Steel pipeline main

ii. Medium pressure Steel pipelines

iii. Low pressure MDPE mains

iv. Low pressure MDPE services

v. CGS/ DRS / Hot Taps

vi. Service Connections

5.2. Various Stations Involved in The Network

The various stations involved in the network are:

a) City Gate Station (CGS)

b) Pressure Reduction Station (PRS)

c) District Regulating Station (DRS

a. City Gate Station (CGS)

CGS for the network is normally located at Tap off point of the main transmission

line or else connected by a spur line to the main transmission line. The CGS has an inlet

supply mains from the transmission pipeline, a pressure reduction system, a filtering unit,

gas chromatograph and metering, odorant injection system and associated piping along

with various monitoring and control systems.

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Graduate Report 2012-2013

The gas transported at city gate station is at a high pressure. The pressure reduction

facility comprises pressure regulator runs with standby units, each having an active /

monitor regulator, each fitted with `slam-shut’ protection facilities. In addition, provision

can be made for natural gas pre-heaters, as per the design requirements.

It is recommended that a CGS be located in a fenced off secure area. To supply the

remainder of the distribution system from the 26 bar maximum transmission pressure

system, `DRS’ is required. The DRS will be similar in design to the City Gate with

different capacity, except no allowance is normally required for gas heating.

b. Industrial Pressure Reduction Station (IPRS)

IPRS for the network is located in major Industries. It has a pressure reduction

system, a filtering unit, Turbine metering system, valves etc. Based on the consumption

profile of the user, customized arrangements are designed with metering arrangement. The

IPRS has slam shut valves, pressure regulating valves, creep relief valve and vent,

isolation valves, non-return valves and pressure gauges

c. District Regulating Station (DRS

DRS for the network is located at strategic locations which are sometimes also

known as field regulating stations to meet various demand centres for Domestic/ Industrial

segment. It too has a pressure reduction system, a filtering unit, Turbine metering system,

valves etc. Based on the consumption profile of cluster of users, customized arrangements

are designed with online metering arrangement. The DRS too has a slam shut valves,

pressure regulating valves, creep relief valve and vent, isolation valves and no-return

valves.

Basically there are three sections that describe the purpose and different

component of stations located at a pressure levels interface

a) The City Gate : interface between High Pressure and Medium Pressure;

b) The Pressure Reducing Station: interface between Medium Pressure and Low

Pressure.

c) The Service Connection: interface between network and end-user pressure

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5.3. How gas is reached at home?

Natural Gas is transported and supplied to consumer by extensive pipeline network

or cylinder type. The backbone of distribution network is the main steel pipeline that

brings natural Gas from source to the city. Along the steel network, CNG stations are

located at a pressure (200-250bar) for vehicles. The pressure in the main steel pipe line is

19 to 26 bar.

The pressure of gas is reduced to 4 bar through “District regulator station (DRS)

located at various points on steel pipe line network. The medium density polyethylene

pipeline (MDPE) network takes off distributing natural Gas. The pressure should be 4

bar to 110 mbar at service regulator. Further pressure reduction is done from 110mbar to

21mbar at metre regulator. The pressure regulator maintains the specified pressure. The

metering device installed in the customer records the unit of gases consumed

Gas Supply System:

a. The Service Regulator: This reduces the gas pressure from 4 BAR to 110 m BAR

and ensures the flow of gas at constant pressure at all time.

b. Buried Polyethylene Pipes: The pipes are installed at a safe and secure depth. It

provides low-pressure gas (110 m BAR) to individual buildings.

Figure: Gas Supply System

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c. The Riser Pipe (GI pipe): This is an external connection on the building to each

apartment. Each Riser Pipe (GI pipe) has a Riser Isolation Valve.

d. The Meter Control Valve: Fitted in the entrance of your house / flat, this valve is

between the riser pipe and your meter.

e. The Meter Regulator: Installed before the meter, the meter regulator reduces the gas

pressure from 110 mBAR to 21 mBAR.

f. The Appliance Valve: This valve switches on/off the gas to burning appliance.

5.4. Challenges in City Gas Distribution Network

City gas distribution network has different routes of varying lengths and sizes crossing

various hurdles and catering to different end users. The challenges start from the very

beginning of the project when the network is to be laid and continues when the network

comes into operation. As more and more number of branches and consumers are added to the

network, the complexity goes on increasing.

The various challenges in city gas distribution network can be categorized under two broad

heads as below –

a) Setting up the Network

b) Operation & Maintenance of the Network

a. Setting up The Network

No separate corridors or ROW is available in the city area for laying of gas pipelines. The

pipeline is to be laid along the road side or under the pathways in whatever space is available

along with the other utilities like telecom cables, water pipes etc. Due to city congestion and

traffic not enough working space is available for pipeline construction activities. Large

numbers of metalled and unmetalled road crossings along with drains etc are to be made to

take pipeline to the various end users. Each end user means a separate branch line for the

user. As the pipeline is laid in the limited space available in parallel crossing the other

utilities, additional precautions and care is required so that the other or utilities do not get

damaged. Where steel pipelines are used, providing effective cathodic protection for the city

pipeline network is also a challenging task. As safety cannot be compromised, all the

standard codes in design and construction have to follow and compliance has to be strictly

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ensured. The dynamic nature of city gas distribution, with frequent addition of new

consumers also requires continuous up gradation and expansion of pipeline network.

b. Operation and Maintenance

Once the network has been set up and gas is charged in the pipeline network, it is not only

required ensure continuous availability of gas to the consumers but also to maintain the health

of the pipeline system. The safety of the system and the surrounding areas is of paramount

importance in city area. A small leakage or an accident / fire in gas pipeline may result into a

big catastrophe. A quick vigil is required to be maintained by the O&M personnel to face the

following challenges in the city gas distribution.

1. Safety and Emergency preparedness.

2. Customer related operations like

a. Proper metering and billing.

b. Changing pressure and flow requirements of consumers.

c. Shutdown, overdraw, non-payment by the consumers.

d. Consumer education and training.

3. Liasoning with District Authorities and other utility departments

Figure: Existing CNG Station in Surat

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6. Summary

Time has come when Natural Gas as an industrial, domestic and automotive fuel is

gaining popularity in India. The Natural gas supply scenario in India has changed

dramatically over a period of time. Natural Gas has emerged as most preferred fuel all over

the world. It is growing in fastest pace and India consumption is 9% to 25% at 2025

This is reflected in the fact that India today operates the largest fleet of CNG buses in

the world. With recent gas finds and import of gas, the gas shall be available in abundance in

the years to come. Keeping in tune, the City Gas network in the existing cities are expanding

and also City Gas Pipeline Networks are being set up to cover more cities not only for

industrial supply but also for the domestic as well as automotive sector. This possesses

greater challenges for the personnel involved in setting up, operating and maintaining the

City Gas Distribution Pipeline Networks.

References:

1. “Energy Statistics” 2012 (Nineteenth Issue), issued by Ministry Of Statistics And

Programme Implementation Government Of India, New Delhi.

2. Nitin Zamre,” City Gas Distribution Projects” November 2009), issued by CRISIL

Infrastructure Advisory.

3. “Basic Statistics on Indian Petroleum & Natural Gas” (2011-2012), issued By

Ministry Of Petroleum & Natural Gas Government of India New Delhi (Economic

Division).

4. Ayush Gupta, “Preparedness to Handle Emergency in City Gas Distribution

Networks, published in 4th Pipeline Technology Conference 2009.