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Steel Plant By- Product Fuel Gas Pipelines

Gas Safety Practices & Gas Management

Durgapur Steel Plant

Presented by : Shri U N Barman Shri B K Pandey Shri B K Goswami Shri Somashish Saha

DURGAPUR STEEL PLANT

FUNCTIONS OF ENERGY MGMT DEPT.

• Distribution & Control of Gaseous fuel

• Operation & maintenance of :

• BF ,CO & BOF gas holders

• 2X 200 T New Propane Storage & Handling System

• Gas mixing station for MSM & NDP

• BOF & Rolling Mill gas boosters

• Operation of SMS & ASP gas boosting stations

• Maintenance of gas pipe lines, accessories & structures

• Energy Cell

• Gas Safety


Gas Type Line length (Km)

Water seal nos Drip pots

CO Gas 11.3 38 278

BF Gas 3.5 28 105

BOF Gas 1.3 02 25

Mixed Gas 3.2 10 67

Propane pipe length 1.4 km

Purging nitrogen pipe length 6 km

Expansion joints 425 nos

Drain Valve 650 nos

Structures 897 nos

GAS NETWORK & ACCESSORIES


• Preliminaries : – Protocol with the detailed break up of the jobs in consultation with

concerned agencies

• Isolation : – Progressive Isolation

– First isolation at consumer end

– Then main line isolation by water sealing

– A blank plate is inserted after the drain valve of water seal

• De-pressurising the gas main: – After water sealing the gas main, vent/bleeder valve is opened for

releasing pressure from the gas main

• Purging :

– Nitrogen purging of the isolated section is done. Nitrogen must come out from the end vent/bleeder. Pressure of nitrogen inside the gas main is regulated to avoid breaking of water seal.

PROCEDURES FOR GAS LINE ISOLATION & CHARGING


• Clearance for starting the job: – Sample from the end bleeder/vent is checked for CO and oxygen

concentration. Also explosive limit is checked through LEL meter. Before giving clearance to start the job, flame test is being done and noted in the work permit.

• Charging of gas line: – Before charging the gas line clearance is taken from the job coordinator and it

ensured that no job is being done on and around gas line.

– Line is pressurized by nitrogen.

– Leakage is being checked with soap water solution.

– Oxygen concentration is checked from the end vent/bleeder.

– Line is charged by breaking the water seal.

– Clearance given to the consumer for consumption.

PROCEDURES FOR GAS LINE ISOLATION & CHARGING


• Preliminaries :

– Protocol with the detailed break up of the jobs in consultation with concerned agencies

• Procedure :

– Thickness of the area where welding is to be done is checked by ultrasonic thickness meter. Min. thick of pipe should be 6 mm

– Provision is made for nitrogen for cooling as well as extinguishing fire, if any

– Provision for water spraying from nearby fire hydrant / Fire Tender

– Area around the place of work kept free from inflammable material.

– Plugging of all the leakages, if any, by putty

– Reduction of gas line pressure.

– Checking of gas concentration in the vicinity

– Proper scaffolding done if required

– Clearance given for welding of the live gas line

– The job is undertaken under an experienced supervisor

LIVE GAS LINE MAINTENANCE PROCEDURE


• Durgapur Steel Plant has a low pressure system of by-product gases

• For every consumer there is provision of isolation through water seal (total 78 nos. throughout the plant)

• Most of the water seal pits in DSP are at minus level by design. The drain line and overflow line are submerged in the pit.

• The drain valves are always in open condition and the overflow line valve is partly throttled. This is a normal operating condition of a charged gas line.

• Provision made for make up water in the seal pots (evaporation loss)

• More than 95% of the water seals have an overhead water tank for quick isolation.

WATER SEAL POTS OF GAS LINES

Overflow Line

Inlet Line

Inlet Line v/v

Drain Line

Drain Line v/v

Overflow Line v/v

Pit Outlet

Tank Overflow

Gas Main

Overhead Tank

Water Source Line


Sample copy of Protocol

• Protocolforshutdownof1600NBmainCO.pdf

Protocolforshutdownof1600NBmainCO.pdf


• The drain line valve is fully closed

• A spade is given after the drain line valve

• The overflow line valve is fully opened

• The water inlet line valve to water seal is opened for filling

• When water comes out from the overflow line valve, the water inlet line valve is throttled

• Controlled water flow is ensured from the overflow line

OPERATION OF WATER SEALS


• Physical inspection of water seal fortnightly

– any leakage from the valve

– pipeline condition

– pit cover condition

– structure and saddle condition

– overhead tank condition

– submerged pipe condition (the pipes are taken out of the pit by closing the valves)

• Servicing of all the valves fortnightly

• Conversion of all submerged pipes from MS to SS

• Rectification of overhead tank leakages, if any.

MAINTENANCE OF WATER SEALS


• Proper SOP is being maintained for any gas crisis situation.

– Priority wise gas restriction to the consumer is listed

– Gas holders are taken online

• Provision of interconnection of CO & BF gas line is present in Durgapur Steel Plant to maintain a minimum 100 mmWC network pressure. Gas of the higher network pressure is being connected with the low network pressure

GAS MANAGEMENT DURING CRISIS SITUATION


• Leaking gas catches fire in contact with ignition source

– Do not Panic

– Use wet gunny bag / jet of steam in case of minor fire

• IN CASE OF MAJOR FIRE

– Inform Fire Brigade

– Arrange for cooling of adjacent pipe & structure

– Reduce gas press. to 100 mmwc. Inform Gas Control

– Inject steam / nitrogen on the upstream side

– Use Extinguishing media

GAS MANAGEMENT DURING CRISIS SITUATION


• Physical inspection of gas pipeline quarterly

• NDT test conducted, whenever necessary

• Pressure survey is done as per requirement to find out choking

• Plan for replacement of pipes done in case of any damage/ choking

GAS LINE INSPECTION


• 4 nos. air line system for working “On line” from compressed air • Compressed air line along gas line in some areas for Gas masks • 3 nos. electrically operated Portable Compressor for working on-

line • 15 minute BA set (5 nos). 45 minute BA set (5 nos) • 1 no. air filling compressor for filling the BA set. • 6 nos. Resuscitation Apparatus are available at different locations • 3 nos. new Oxygen Therapy Inhaler have been procured for

preliminary administration of Oxygen • Fixed and portable CO monitors in many locations

GAS SAFETY EQUIPMENT


• As per IPSS, inspection of gas line will be recorded in every 3 months instead of yearly

• Water seal inspection done fortnightly instead of monthly.

• Make up water line for drip pots

• All submerged pipes of water seals changed in Dec 2017

• Modification/repair of make up water for water seal pits

• Replacement of submerged pipes of water seals and drip pots by ‘SS’ pipes.

• All the submerged pipes to be replaced within 2-3 years irrespective of the health

GAS SAFETY INITIATIVES


• Training by external faculty / experts

• Gas Safety Awareness programmes at CHRD and Dept.

• Training on First aid and Artificial Respiration

• Training on Disaster Management and Rescue Techniques

• Mock Drills with Fire Service Dept

• Daily Safety Talk by line managers, supervisors

PREPARING PEOPLE FOR GAS SAFETY

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