Environmental performance is a key benchmark for contemporary Integrated Gasification Combined Cycle (IGCC) plant designs. IGCC boasts high marks in environmental performance derived in part from both the fundamental environmental characteristics of the process as well as advances in gas turbine combustion technology. The earliest commercial-scale coal IGCC plants are still achieving levels of criteria pollutants lower than those of recently permitted direct combustion plants. Additional advancements are providing further improvement in environmental performance as well as capability to deal with a broadening range of applications.
IGCC systems provide significant environmental benefits through lower solids production, lower criteria pollutant emissions, and income from byproduct sales when applied to the clean conversion of opportunity fuels such as petroleum coke, refinery residuals and biomass. In addition, the capability of gas turbine combustion systems to accommodate a wide variety of fuel gas compositions allows for effective process integration with gasification systems enabling “poly-generation” of hydrogen and steam, with provisions for cost effective “pre-combustion” CO2 removal.
The future viability of IGCC is ensured by its capability to meet developing standards in Mercury and HAPS reduction. IGCC also has promising process paths and economics for low CO2 power enabled by the capability of gas turbines to combust high-hydrogen, carbon-free gaseous fuel.
The robustness of the gasification process to handle a wide range of solid and liquid fuels has been demonstrated in applications using coal and refinery wastes in roles of power and chemical co- production. Current gas turbine combustion control systems provide for full and/or co-firing of synthesis gas with natural gas or distillate fuel providing high power availability with extensive operational flexibility needed to serve today’s dynamic energy markets. The high power and chemical production availabilities demanded by refineries can be achieved by IGCC system design through multiple gasifier and power trains, combined with the gas turbine’s capability to use backup fuels with seamless transfer between fuel sources.
Continuous improvements in gas turbine technology and performance are rapidly driving IGCC systems costs down the learning curve. The fuel cost sensitivity curve shows IGCC to be a viable commercial contender for low cost opportunity fuels and high sulfur coal as natural gas prices continue to trend upward.
GE gas turbines have accumulated more than 500,000 fired hours on a broad range of synthesis fuels, which to a large degree have been enabled by continuous developments in gas turbine technology. Fuel flexibility and high system reliability afforded by today’s gas turbines are critically important to the economic success of solid fuel based IGCC projects. IGCC plant designs currently enjoy compelling environmental advantages for waste fuel conversion to economical poly-generation products, and provide additional system flexibility and growth potential to meet future regulatory challenges.
4.- Reactor Solena