City Gas Distribution: A City Gas Distribution: A Network AnalysisNetwork Analysis

Overall viewOverall view

City gas distribution in IndiaCity gas distribution in India

Oil India ltd. was first to start distribution gas in Oil India ltd. was first to start distribution gas in Assam in 1960’s.Assam in 1960’s.

As a pilot project first city gas distribution was As a pilot project first city gas distribution was taken up with help of ONGC at Vadodara city in taken up with help of ONGC at Vadodara city in 1972.1972.

GGCL was the first commercial city gas GGCL was the first commercial city gas distributon company in India.distributon company in India.

MGL & IGL starts city gas distribution in MGL & IGL starts city gas distribution in domestic, commercial & transport sector in domestic, commercial & transport sector in Mumbai(1995) & Delhi(1998) respectively. Mumbai(1995) & Delhi(1998) respectively.

Natural GasNatural Gas

Why Natural gas?Why Natural gas?

Advantages:Advantages:1.1. Safe and clean fuel.Safe and clean fuel.

2.2. Excellent combustion properties.Excellent combustion properties.

3.3. Cheap and easily available.Cheap and easily available.

4.4. Future fuel.Future fuel.

Demand of Natural GasDemand of Natural Gas

Domestic gas demand in India is of order Domestic gas demand in India is of order of 179MMSCMD in 2006-07.of 179MMSCMD in 2006-07.

Consumption of Natural gasConsumption of Natural gas

FeasibilityFeasibility

System designSystem design

Selection of route.Selection of route. Optimum route.Optimum route. System basic conceptSystem basic concept

Selection of routeSelection of route

Maximum reach of potential demand Maximum reach of potential demand centers with minimum length.centers with minimum length.

Use of existing defined pipeline corridors Use of existing defined pipeline corridors by respective authorities.by respective authorities.

Minimum disturbance to agricultural land.Minimum disturbance to agricultural land. Safety of people and property.Safety of people and property. Avoidance of rocky terrain.Avoidance of rocky terrain. Flexibility of future expansion.Flexibility of future expansion.

Optimum routeOptimum route

Shortest length of pipeline grid.Shortest length of pipeline grid. Least topographical variation and Least topographical variation and

minimum obstacles.minimum obstacles. Minimum cost of system layout.Minimum cost of system layout. Density of traffic should be low.Density of traffic should be low. Minimum no. of turning points.Minimum no. of turning points.

System basic conceptSystem basic concept

Pressure levels Pressure levels

High pressureHigh pressure (49 barg)(49 barg)

Medium pressureMedium pressure (26 barg)(26 barg)

Low pressureLow pressure (4 barg)(4 barg)

NetworkNetwork

Steel mains (network) Steel mains (network)

High pressure mainsHigh pressure mains

Medium pressure mainsMedium pressure mains

Above ground mainsAbove ground mains Polyethylene Polyethylene Cover clearance protectionCover clearance protection Sectionalizing Sectionalizing

Construction activitiesConstruction activities

Opening of Right of WayOpening of Right of Way Clearing & gradingClearing & grading Welding & radiographyWelding & radiography Joint coatingJoint coating CrossingsCrossings Hydrostatic testing Hydrostatic testing

Sectors for city gas distributionSectors for city gas distribution

CNG – Transport sectorCNG – Transport sector

PNG – Domestic sectorPNG – Domestic sector

PNG – Commercial sectorPNG – Commercial sector

PNG – Industrial sectorPNG – Industrial sector

Various station involved in networkVarious station involved in network

City gate station (CGS)City gate station (CGS)

Industrial pressure reducing station (IPRS)Industrial pressure reducing station (IPRS)

District regulating station (DRS)District regulating station (DRS)

Layout of service connectionLayout of service connection

Mild density polyethylene (MDPE) as gas Mild density polyethylene (MDPE) as gas pipe.pipe.

Domestic connection layoutDomestic connection layout

MDPE as gas pipeMDPE as gas pipe

Balance rigidity & toughnessBalance rigidity & toughness Excellent ductilityExcellent ductility Very low permeation to gasVery low permeation to gas Resistance to rapid crackResistance to rapid crack Extremely smoother interior surfaceExtremely smoother interior surface Easy to transport, handle & layEasy to transport, handle & lay Longer life Longer life

Domestic connection layoutDomestic connection layout

Polyethylene Pipe Joining Polyethylene Pipe Joining

An integral part of any pipe system is the method An integral part of any pipe system is the method

used to join the system components.used to join the system components.

Thermal heat fusion methodThermal heat fusion method

1. Butt fusion1. Butt fusion

2. Saddle/conventional fusion2. Saddle/conventional fusion

3. Socket fusion3. Socket fusion Electro fusion Electro fusion

Thermal Heat Fusion Thermal Heat Fusion

Principle of heat fusion is to heat two Principle of heat fusion is to heat two surfaces to a designated temperature and surfaces to a designated temperature and then fuse them together by application of then fuse them together by application of sufficient force.sufficient force.

Butt fusionButt fusion

Most widely used method of joining.Most widely used method of joining. It produces permanent, economical and It produces permanent, economical and

flow efficient connection.flow efficient connection.

Saddle/conventional fusionSaddle/conventional fusion

This is used to join a saddle to a pipe.This is used to join a saddle to a pipe. The external surface of both the pipe is The external surface of both the pipe is

heated and the matching surface are fitted heated and the matching surface are fitted with the help of concave and convex with the help of concave and convex shaped heating tools.shaped heating tools.

Socket FusionSocket Fusion

In this technique, both the internal as well In this technique, both the internal as well as the external surface is heated.as the external surface is heated.

Electro FusionElectro Fusion

Maintenance Maintenance

Pipeline failure investigationPipeline failure investigation

Periodic surveillance of pipelinesPeriodic surveillance of pipelines

Cathodic protection.Cathodic protection.

Future advancementFuture advancement

Details of Non returning valve & metering Details of Non returning valve & metering device used in door to door supply of device used in door to door supply of PNG.PNG.

Fabrication of NRVFabrication of NRV Electric log model of city gas distributionElectric log model of city gas distribution Details of horizontal directional drilling & Details of horizontal directional drilling &

auger boring.auger boring. Flow rate calculation of particular sections Flow rate calculation of particular sections

of a pipeline.of a pipeline.