refining india 2023
Transforming hydrogen production for a greener future with water electrolysis
Jagadesh Donepudi and Rodolfo Tellez-Schmill KBC, a Yokogawa company
between 5 and 10 USD/kg compared to grey hydrogen, which costs about 1.5 USD/kg. Monitoring Water Electrolyser Performance In this dynamic area, process simulation models have become increasingly impor- tant. With a simulator, the user now has the ability to model alkaline, PEM, anion exchange membranes, and solid oxide electrolysers. Users can build digital twins for green hydrogen production processes for design and operation. Furthermore, operation engineers can leverage digital twins to monitor the performance of the water electrolyser. It helps pinpoint poten- tial issues related to asset performance, such as electrode degradation, corrosion, and excessive energy costs. Process simulator software can be used to build simulations and digital twins of water electrolysers to perform the follow- ing activities. • Design engineering : Process simula- tion models support critical process and mechanical design activities, including flowsheeting, heat and mass balances, equipment sizing, process optimisation, equipment/instrumentation datasheets, equipment and piping material selection, designing process control strategies, as well as assessing hazards and operability. • Plant operation : Process simulation models, when connected to plant data, create a digital twin, aiding asset monitor- ing, data reconciliation, unit monitoring, optimisation, retrofitting, energy manage- ment, and emissions monitoring to ulti- the PEM electrolyser is easy to handle and maintain while mately enhance profitability and safety. • Operators training : Dynamic simula- tions can be incorporated into operators’ training systems to expedite the learning curve of how the system works before the plant is commissioned. • Real-time optimisation and advanced process control : Process simulation mod- els enable ongoing adjustment to market changes, disturbance accommodation, plant optimisation, retrofitting, and hazard reduction to increase profitability. • Research and development : Process simulation models facilitate in-depth analy- sis of current technologies, exploration of future technologies, and identification of potential challenges within the electrolysis domain. generating high- purity hydrogen
There is a global trend toward producing clean hydrogen to achieve the ambitious net zero emissions target by 2050. The US government has made strides in this direction, recently publishing its National Clean Hydrogen Strategy and Roadmap. 1 Underlying this initiative is the goal to reduce greenhouse gas emissions by 50% from 2005 levels by 2030. Along with this initiative is the need to produce affordable, clean hydrogen, with a target price of 1 USD/kg of hydrogen in one decade. Currently, the estimated pro- duction cost of hydrogen via electrolysis ranges between 5 and 7 USD/kg of hydro- gen. The US aims to produce 10 million metric tons (MMT) of clean hydrogen per year, mirroring similar targets from the EU across all its member states by 2030. Within the realm of hydrogen production, the use of alkaline electrolysis is well-estab- lished. While it has been applied on a large scale for decades, it also presents technical challenges. These obstacles include high energy consumption, installation costs, and maintenance costs due to corrosive alkali materials. The proton exchange mem- brane (PEM) electrolyser represents a new technology. It is easy to handle and main- tain while generating high-purity hydrogen (99.99% dry basis). PEM, however, also displays some flaws, such as high manufac- turing costs for membranes and requiring precious metals for electrodes. The Government of India announced its Green Hydrogen Mission² to achieve net zero emissions by 2070. This green initia- tive spans multiple sectors, including refin-
Electric power
Hydrogen_PEM
Hydrogen_PEM 1949 STD_m /h
166.6 kg/h 100.0 wt %
PEM electrolyser
Figure 1 PEM electrolyser in Petro-SIM process simulator
1.50
1 atm 1 atm 5 bar 5 bar 10 bar 10 bar 30 bar 30 bar 50 bar 50 bar 90 bar 90 bar
1.45
1.40
1.35
1.30
1.10 1.15 1.20 1.25
100 120 140 160 180 200 220 240 260 280 Temperature (˚C)
0 20 40 60 80
300
Figure 2 Voltage calculations for electrolysis at different pressures and temperatures
Producing Green Hydrogen The important aspect of producing green hydrogen involves the electrolyser, which is the technology that splits water into its core elements of hydrogen and oxygen. They are important for efficient and scal- able hydrogen production. The estimated cost of producing green hydrogen ranges
ing and petrochemical processes, fertiliser production, mobility, steel manufacturing, and railways. This road map includes man- ufacturing 5 MMT/year of green hydrogen through green electricity and bioprocesses by 2030, where refineries and fertiliser manufacturers are the major consumers of this resource.
2.1 2.0 1.9 1.8 1.7 1.6 1.5 1.4 1.3 1.2
54 53 52 51 50 49 48 47 46 45 44 43 41 42 40
Current density, A/cm
H production rate, kg/h
1800 1600 1400 1200 1000
0.1 0.09 0.08 0.07 0.06 0.05 0.04 0.03 0.01 0.02 0
800 600 400 200 0
Electric power, kW
Current density, A/cm
Figure 3 System curves assess voltage requirements and hydrogen production
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