Domestic Gas Infrastructure

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  • 1. 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,
  • 2. 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
  • 3. 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.
  • 4. 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
  • 5. 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
  • 6. Graduate Report 2012-2013 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
  • 7. 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
  • 8. 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.
  • 9. Graduate Report 2012-2013 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
  • 10. Graduate Report 2012-2013 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.
  • 11. 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
  • 12. Graduate Report 2012-2013 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
  • 13. Graduate Report 2012-2013 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
  • 14. Graduate Report 2012-2013 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
  • 15. Graduate Report 2012-2013 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.