Zero emission hydrogen-oxygen internal combustion steam cycles with coal gasification and CO2 removal

This paper analyses the performance of an advanced zero-emission power plant based on a stoichiometric hydrogen-oxygen combustion steam turbine cycle, integrated with coal gasification and physical absorption and liquefaction of carbon dioxide. The power cycle is a sort of innovative combined cycle, with steam as working fluid. The topping cycle is a steam Brayton Cycle, the bottoming one a supercritical Hirn cycle. The attention is focused on optimisation of the power cycle and evaluation of the power requirements for hydrogen production. In particular, two different technology levels for the inlet turbine temperatures are investigated: the first level scenario reproduces the inlet temperature of the modern gas turbine and ultra-critical steam cycle, while the second represents the temperatures that could be attained in the near future. The best configuration showed a net thermal efficiency of approximately 42% with zero-emission.