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Delivering Clean Energy to Your Doorstep
CNG Safe Operating MethodPT IEV Gas - 2014
Prepared by Danu Jaya
IEV GAS Business Model
Tube Skid Unit
TRANSPORT EQUIPMENT
►US DOT 49 CFR § 178.37 “Specification
3AA and 3AAX seamless steel cylinders”
►ISO 11120 – Gas Cylinders – Refillable
seamless steel tubes for compressed gas
transport, of water capacity between 150l
and 3000l – Design, Construction and
Testing
The manufacturing of the CNG tubes are in compliance to:
CNG Daughter Station (DS) Process
CNG VEHICLE
PRU(PRESSURE
REGULATOR UNIT)CUSTOMER
Natural gas properties – Ignition and fire Gas released in the open space will quickly
disperse harmlessly Gas in a confined space, if ignited, will
create a localized high pressure Confined areas are pits, ceiling or roof
pockets. The gas/air concentration range for
flammability is narrow at low pressure (5 to 15% by volume)
Safety characteristics – natural gas and CNG
Properties of Natural Gas
1971
1 0
Properties of Natural GasOdorless – Colorless -
Tasteless
Methyl Mercaptan is added to give it it’s distinguishable “rotten egg” odor
Odorized natural gas is detectable at concentrations significantly less than 1%
Properties of Natural Gas Non-Toxic
75~95% - methane
Often listed as a “Hazardous Material” due to it’s flammability, not it’s toxicity
Only through it’s ability to displace oxygen can it pose an asphyxiation hazard
9
Properties of Natural Gas
10
Properties of Natural Gas Vapor Density
30% lighter than air
Will rise to sky, or collect near the ceiling
Natural Gas0.6
Air = 1
Propane1. 56
Properties of Natural Gas Flammable
Limits
5%
Too Lean
15%
Too Rich
Properties of Natural Gas Heating Value
1,000 BTU per cubic foot
Properties of Natural GasCombustion Products
Complete combustion = heat, carbon dioxide & water vapor
Incomplete combustion = carbon monoxide
14
Properties of Natural Gas Auto Ignition
Temperature
Natural Gas :1163º F / 628 º C
Propane : 957º F / 514º C
Gasoline : 632º F / 333º C
Safety Devices installed on equipment that placed on customer site (DS)
◦ Tube Skid Safety Devices
◦ PRU Safety Devices
◦ Heater Safety Devices
Safety Equipment on DS process
Rupture Disc◦ A rupture disc, also
known as a bursting disc or burst diaphragm, is a non-reclosing pressure relief device that, in most uses, protects a pressure vessel, equipment or system from over pressurization or potentially damaging vacuum conditions
TS Safety Device
PRU installed with several safety devices, mechanical protection and static electrical protection. Those devices are:
◦ PSV◦ ESD System◦ Earth System◦ Electrostatic discharge system◦ Hose Restrain System
PRU Safety Devices
Pressure Safety Valve◦ is a valve mechanism
which automatically releases a substance from a boiler, pressure vessel, or other system, when the pressure or temperature exceeds preset limits
PSV System
The CNG PRU packages are provided with an Emergency Shut Down System Device.
The ESD system is activated when pressure exceeding preset pressure
The ESD system, when activated, ◦ Brings the unit to an immediate
halt.◦ Isolates the unit from Gas Suction
Line.◦ Closes all the output priority valves,
thus isolating the Compressor, Cascades & Dispensers from each other.
ESD System
The filling Hoses of CNG Dispensers are Electrically Conductive & designed as per ANSI / NGV 4.2
Static charge is carried to dispenser body, and does not produce spark during engagement and disengagement of Filling nozzle with Vehicle receptacle.
The dispensers are Earthed to dissipate the Static Charge, and leakage current if any.
Conductive Hose & Earthing
Anti Static Cable(earthing)
To prevent hose accidentally disengage in hazardous movement, hose restrain system installed during hose connection process before opening TS valve.
Restrain system can hold 2000 Kgs force
Hose Restrain System
Water Heater Installed to prevent gas pipe in PRU to became freezing due to gas flow.
Working temperature set on maximum 80oC
Temperature Control Device Installed to prevent the system overheating.
Water Heater Safety Device
Do and Don'ts
Do Risk Assessments prior to work
Do Safety Awareness to Team work
Do inspection of Safe Condition
Do proper PPE according to risk
Do follow safety instruction
DO
Don’t make any naked fire
Don’t ignore small case, big thing came up from small
Don’t do if you’re don’t know
Don'ts
July, 2014 PT IEV Gas
Thank You