2025 Spring Meeting and 21st Global Congress on Process Safety
(127c) Risk Assessment of Hydrogen for Use in Hazardous Process
Author
Abhineet Raj - Presenter, Tata Steel Ltd.
CO2 emissions in BF-BOF based steel industry is mainly attributedto usage of coal as a fuel & reducing agent for smelting of iron ore.This results in emission of approximately 1.80 tons of CO2 pertonne of hot metal. In line with fuel rate reduction in iron makingthrough blast furnace route, alternate fuel injection, alternatereductants are being practiced in different parts of the world. Mostof these also are hydrogen rich. These injectants also lead toreduction of CO2 footprint, thereby participating in carbon directavoidance (CDA). Different such possible injectants, that are beingin use are oils, tar, natural gas, hydrogen, coke oven gas etc.
Our company recently concluded its one of its kind, month-longtrial with Coal Bed Methane (CBM) injection in one of its blastfurnaces with encouraging results in terms of lowering of cokerates. Considering the same, effort was made to inject purehydrogen in one of its blast furnaces.
News publication link:
Tata Steel initiates trial for record-high hydrogen gas injection inBlast Furnace at its Jamshedpur Works
Scope of the project:
Hydrogen injection trial was done in 4 tuyeres via hydrogen tanker.This helped in gaining important answers related to technologyrequired for safe handling and injection of hydrogen in blastfurnace.
Project Description:
Trial was carried out with hydrogen injection via 4 tuyeres in one ofthe blast furnaces. Main objectives of this revolves around learningusage of hydrogen and are listed as follows:
Hydrogen handling and safety concerns
Basic engineering
Plant technology requirements
Suitability and compatibility of injection hardware
Hydrogen supply for these trials was sourced using truck mountedcascades from potential suppliers along with necessary skid forregulating pressure for injection. Pressure reduction skid andtransportation pipelines was laid from tanker position tilldesignated tuyere for injection with all safety features andinterlocks.
Injection Scheme:
In the existing tar injection system at one of the blast furnaces,there is a compressed air system present for cooling of the lance.In the concentric lance, tar travels from the center and compressedair flows through the annulus. In this system, compressed airsystem was used for hydrogen injection with no-tar.
The proposed system was itself a unique design and was modifiedconsidering the hazards of blast furnace and peripheral area
Challenges in Hydrogen Handling:
Very Low Ignition energy - 0.017 mJ
as compared to other gases.
Wide range of explosive mixture 4 – 72% as compared to othergases.
Leakage probability due to low molecular weight of H2 & Highpressure handling
Colourless and odourless and can embrittle some metals
Uniqueness:-
HMI developed with PSM critical real time parameters with morethan 100 safety interlock was built in the logic.
Automatic stoppage of H2 in case of trip activation interlock andimmediate switchover to N2 Inertising/ purging sequence in eachtripping.
Real time simulations & testing of all safety interlocks was donebefore injection start up.
Total no of H2 Tankers used –25 Nos with Hydrogen TankerPressure - 200 bar and Furnace Injection pressure – 4.5 Bar
Two stage Pressure reduction from 200 bar to 8 bar and from 8bar to 4.5 bar with pipeline distance from tanker to furnace ~ 300mtr
Excess flow check valve and three way valve with changeoverfacility and start of purging and venting
Elimination of entire electrical system from high pressure PRSwhere multi fold pressure reduction (15 times) is done
The 1st stage PRS is an inherently safer and reliable design as itconsists of mechanical system only, even the flow control valvesetc are free from electronic and electrics.
Safe logistic management of tankers to support the peak hydrogeninjection rate @ above 1500 nm3/hr
The entire injection process of 38000Nm3 is completed safelywithout a single leak
Unique system followed to detect leak during injection trial ofduration 60 hrs with the help of portable electrochemical H2 PPMdetector and Thermography camera as hydrogen leakphenomenon follows opposite to Joule Thomson effect
There was no unintended leakage of hydrogen.
Hazop, Consequence modelling through PHAST software, BowTie, PSSR conducted before the trial.
Achievements:
Our company became 1
to inject such large volume of hydrogenin any Blast Furnace
st
During Hazop, 52 number of high risk scenarios were identified and mitigated at the design phase itself
Hydrogen Injection is one of the key strategy of our company in the decarbonisation journey . The endeavour is aligned with theCompany’s vision of becoming Net Zero by 2045 kick started withthis project
The trial has the potential to reduce the coke rate by 10%,translating into around 7-10% reduction in CO2 emissions per tonof crude steel produced saving millions of money.
Very encouraging process results were observed during the trialand team learnt Safe handling/managing hydrogen injection inBlast Furnace.
The process sees hydrogen substituted in for carbon as thereducing agent in the extraction process at 40% of the furnace’sinjection systems.
Our company recently concluded its one of its kind, month-longtrial with Coal Bed Methane (CBM) injection in one of its blastfurnaces with encouraging results in terms of lowering of cokerates. Considering the same, effort was made to inject purehydrogen in one of its blast furnaces.
News publication link:
Tata Steel initiates trial for record-high hydrogen gas injection inBlast Furnace at its Jamshedpur Works
Scope of the project:
Hydrogen injection trial was done in 4 tuyeres via hydrogen tanker.This helped in gaining important answers related to technologyrequired for safe handling and injection of hydrogen in blastfurnace.
Project Description:
Trial was carried out with hydrogen injection via 4 tuyeres in one ofthe blast furnaces. Main objectives of this revolves around learningusage of hydrogen and are listed as follows:
Hydrogen handling and safety concerns
Basic engineering
Plant technology requirements
Suitability and compatibility of injection hardware
Hydrogen supply for these trials was sourced using truck mountedcascades from potential suppliers along with necessary skid forregulating pressure for injection. Pressure reduction skid andtransportation pipelines was laid from tanker position tilldesignated tuyere for injection with all safety features andinterlocks.
Injection Scheme:
In the existing tar injection system at one of the blast furnaces,there is a compressed air system present for cooling of the lance.In the concentric lance, tar travels from the center and compressedair flows through the annulus. In this system, compressed airsystem was used for hydrogen injection with no-tar.
The proposed system was itself a unique design and was modifiedconsidering the hazards of blast furnace and peripheral area
Challenges in Hydrogen Handling:
Very Low Ignition energy - 0.017 mJ
as compared to other gases.
Wide range of explosive mixture 4 – 72% as compared to othergases.
Leakage probability due to low molecular weight of H2 & Highpressure handling
Colourless and odourless and can embrittle some metals
Uniqueness:-
HMI developed with PSM critical real time parameters with morethan 100 safety interlock was built in the logic.
Automatic stoppage of H2 in case of trip activation interlock andimmediate switchover to N2 Inertising/ purging sequence in eachtripping.
Real time simulations & testing of all safety interlocks was donebefore injection start up.
Total no of H2 Tankers used –25 Nos with Hydrogen TankerPressure - 200 bar and Furnace Injection pressure – 4.5 Bar
Two stage Pressure reduction from 200 bar to 8 bar and from 8bar to 4.5 bar with pipeline distance from tanker to furnace ~ 300mtr
Excess flow check valve and three way valve with changeoverfacility and start of purging and venting
Elimination of entire electrical system from high pressure PRSwhere multi fold pressure reduction (15 times) is done
The 1st stage PRS is an inherently safer and reliable design as itconsists of mechanical system only, even the flow control valvesetc are free from electronic and electrics.
Safe logistic management of tankers to support the peak hydrogeninjection rate @ above 1500 nm3/hr
The entire injection process of 38000Nm3 is completed safelywithout a single leak
Unique system followed to detect leak during injection trial ofduration 60 hrs with the help of portable electrochemical H2 PPMdetector and Thermography camera as hydrogen leakphenomenon follows opposite to Joule Thomson effect
There was no unintended leakage of hydrogen.
Hazop, Consequence modelling through PHAST software, BowTie, PSSR conducted before the trial.
Achievements:
Our company became 1
to inject such large volume of hydrogenin any Blast Furnace
st
During Hazop, 52 number of high risk scenarios were identified and mitigated at the design phase itself
Hydrogen Injection is one of the key strategy of our company in the decarbonisation journey . The endeavour is aligned with theCompany’s vision of becoming Net Zero by 2045 kick started withthis project
The trial has the potential to reduce the coke rate by 10%,translating into around 7-10% reduction in CO2 emissions per tonof crude steel produced saving millions of money.
Very encouraging process results were observed during the trialand team learnt Safe handling/managing hydrogen injection inBlast Furnace.
The process sees hydrogen substituted in for carbon as thereducing agent in the extraction process at 40% of the furnace’sinjection systems.