Case study
Industry: Petrochemical Plants
ISSUE
Path to decarbonization – Evolving operations
Chemical plant owners are under pressure to further reduce total CO₂ emissions as part of carbon neutral efforts. From the standpoint of their sustainability strategies and ESG mandates looking toward 2050 net zero goals, implementing lower or zero carbon solutions is essential.
Using hydrogen in petrochemical plants to lead the way in CO₂ reductions
Cracking heaters are among the greatest energy-consuming devices at chemical plants, making them one of the largest sources of CO₂ emissions. In many chemical plants, hydro-carbon gases such as methane off gas produced in thermal cracking processes have been utilized as fuel sources to heat and/or power the plants. Advanced ethylene plants have integrated gas turbines into their processes and utilized their off gas as fuel for gas turbines in a combination system that generates both power and heat used within the plant. Changing the use of methane off gas is one of the options for decarbonization. Namely, converting all the off gas to hydrogen as gas turbine fuel with CO₂ capture.
Utilizing reliable gas turbines capable of hydrogen co-firing for cogeneration applications
Blue hydrogen could be a path to CO₂ reduction; however, important questions remain: Can ethylene plants have stable and continuous operations even when using hydrogen? Can they maintain the same heat and power supply necessary for chemical plant operations? One option for chemical plant owners to consider is the installation of a hydrogen-natural gas co-firing gas turbine cogeneration system that can supply both heat and power with excellent overall thermal efficiency and reduce CO₂. This must meet the following three criteria:
- The capability of hydrogen co-firing with other available fuel gas (e.g. natural gas)
- The capability to flexibly switch hydrogen firing to natural gas firing in case of hydrogen production difficulties
- Gas turbine cogeneration systems that can supply both heat and power needed to efficiently operate the plant
Mitsubishi Power is confident that the H-25 gas turbine can fulfill these criteria.
SOLUTION
KEY POINTS TO THE SOLUTION
- H-25 is a pioneer in hydrogen firing gas turbine.
- Multiple options for hydrogen co-firing/100% firing
- Highly efficient cogeneration system providing abundant exhaust heat energy
H-25 is a pioneer in hydrogen firing gas turbine
The H-25 gas turbine was introduced to the market in the 1990s and has an extensive track record in hydrogen co-firing. It has been used for power generation and heat supply using hydrogen-rich fuels in petrochemical and steel plants worldwide.
Multiple options for hydrogen co-firing/100％-firing
With its diffusion combustor, the hydrogen co-firing ratio can be changed from 0% to 100%. Factors to consider when changing the ratio include in-house production costs for blue hydrogen and market prices for natural gas. When a plant owner makes decision to use blue hydrogen with 100% firing in the future, another consideration is to apply a highly efficient dry low NOx (DLN) multi-cluster combustor.
Highly efficient cogeneration system providing abundant exhaust heat energy
H-25 gas turbine's capability to provide exhaust heat in amounts and temperatures higher than other gas turbines in its class makes it ideal for cogeneration plants that require high-temperature and high-pressure steam. The turbine exhaust temperature reaches around 570℃ (37-38 Gcal/h per unit at ISO conditions), reducing the need for additional fuel input to generate steam.
EXPECTED OUTCOME
- Reduces CO₂ by utilizing in-house produced blue hydrogen as fuel
- Optimizes fuel cost by flexibly controlling the co-firing ratio between in-house produced blue hydrogen and natural gas
- Maintains stable plant operation even when changing the fuel source from off gas to hydrogen
