cng operation safety feature

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