Thermodynamic Performances Analysis Of Integrated Gasification Humidification Gas Turbine Cycle

Integrated Gasification Combined Cycle (IGCC) is an important trend of clean coal power generation technology. For the purpose of reducing NOx emissions and using low quality heat efficiently, humidification systems have been combined with different IGCC systems, and based on coal-water slurry gasifier, dry coal pulverization gasifier and fuel flexible gasifier, fuel humidification cycles, IGHAT cycles and air humidification cycles systems retained the steam bottoming cycles (IGLOTHECO) have been established and their thermal performances have been studied, which intends to get some useful suggestions for the humidification methods and humidification degree.Then humidificaion cycles are combined with external low quality heat resources and the system capacity of taking advantage of external low quality heat, for example, solar energy, have been studied, which intends to get some useful suggestions not only for improving system performance of integrated gasification humidification, but also for the efficient and low-cost solar energy utilization. The contents are as follows:1.Component models of integrated gasification humidification systems have been established, including three types of gasifiers, syngas fired gas turbine, air separation unit, humidifier, cleanup unit, heat recovery steam generator, etc.2.One type of fuel humidification and two types of air humidification have been combined with IGCC systems employing different types of gasifiers, and novel processes have been put forward and the requirements for the humidification degree to reduce NOx emissions have been studied. The results show that:to control NOx emissions within the limits, there are some limits to the humidification degree for the workingmedium in different humidification cycles:the humidification degree of the workingmedium in the dry coal pulverization gasifier system is the highest, then is the coal-water slurry gasifier system, that of the fuel flexible gasifier system is the lowest.3.Thermodynamic performances of different novel processes have been analyzed in the same constraint of controlling the NOx emissions.The results show that:as for efficiency, efficiency of fuel flexible gasifier systems is higher, then is the dry coal pulverization gasifier systems, efficiency of coal-water slurry gasifier systems is relatively lower; fuel humidification cycles show more favorable performance than steam injection cycles; systems employing waste-heat boiler are better than those employing quench. As for the specific work of gas turbine, specific work of gas turbine in air humidification cycles is larger than that in fuel humidification cycles.4.Humidification systems are combined with external low quality heat resources, and the system capacity of taking advantage of external low quality heat, for example, solar energy, have been studied. The results show that:except for coal-water slurry IGHAT cycle and fuel flexible gasifier IGHAT cycle systems employing quench which have sufficient low quality heat for workingmedium humidification, other cycles have the potential of taking advantage of low quality heat outside of the system to significantly improve their system efficiency, and incremental solar thermal to electric efficiency of some cycles are far more than that of 14% in solar-only thermal power plant, so sloar systems integrated in humidification cycles have some cost advantages.