United IGCC plants

Several utility-scale demonstration facilities having power outputs in the 300-MW class have been constmcted in the United States and Europe. These started accumulating operating experience in 1995 and 1996. Other IGCC plants have been constmcted, including units fueled by petroleum coke and refinery bottoms. Advanced 500-MW class IGCC plants based around the latest heavy-duty combustion turbines are expected to be priced competitively with new pulverized-coal-fined plants utilising scmbbers. 

Purisol A process for removing hydrogen sulfide from gases by selective absorption in N-methyl-2-pyrrolidone (NMP). Developed and licensed by Lurgi, particularly for desulfurizing waste gases from IGCC plants. Seven units were in operation or under construction in 1996. 

The Power Block in the IGCC plant is essentially a gas turbine unit that operates on syngas. This gas turbine unit is basically the same as that used for natural gas with certain modifications. The areas that are modified and also that need to be critically evaluated for use with syngas are ... 

Capital cost estimates for a new 285 MWe (net) greenfield IGCC plant incorporating lessons learned, technology improvements, and a heat rate of 8526 Btu/kWh are l,318/kW (2000 ) for a coal-fueled unit and 1,260 (2000 ) for a petroleum coke-fueled unit. 

The typical steps for syngas gas cleanup include particle removal, COS hydrolysis, acid gas cooling, sulfur removal, and sulfur recovery. C02 sequestration can be implemented in an IGCC plant by adding additional units in the syngas cleanup section. 

If C02 sequestration is required, an IGCC plant can be easily modified to have such capabilities. Deep decarbonization of syngas requires the addition of a series of WGS reactors and a C02 separation unit to the existing IGCC plant as shown in Figure 11.21. 

While comparison of the absolute capital costs and costs of electricity among different power systems is difficult and uncertain, the structure of these costs is rather typical, and the costs of component units are usually within known ranges. For an oxygen-blown IGCC power system, the breakdown of the capital cost for the four component units is air separation plant (11 to 17 percent), fuel gas plant (33 to 42 percent), combined-cycle unit (32 to 39 percent), and balance of plant (2 to 21 percent). The breakdown of the cost of elec tricity is capital charge (52 to 56 percent), operating and maintenance (14 to 17 percent), and fuel (28 to 32 percent). 

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