Analysis And Optimization Of IGCC Power Generation System

With the development of society and the improvement of industrialization level,demand for electricity and energy is increasing.In China,coal resources are abundant and coal-fired power generation has been the dominant factor.However,the pollutants emitted by thermal power units have caused a great threat to the environment.The integrated gasification combined cycle power generation technology can achieve near zero emission of coal-based.IGCC can effectively reduce the pollutant content of exhaust gas and meet the requirements of environmental protection,and can also realize the cascade utilization of energy.It does not need to solve the problem of raw materials,but also can achieve energy saving and emission reduction,so that the environment can be protected.Therefore,in order to improve the efficiency of the IGCC system,it is very important and meaningful to improve the structure and optimize the parameters of the IGCC power generation system.In the thesis,the gasification process of coal in a gasifier is simulated by the Gibbs free energy minimization principle and the modeling analysis of coal water slurry gasifier is to use the Aspen plus software.The influence of different coal water slurry concentration,oxygen coal ratio,gasification temperature and gasification pressure on crude gas composition,crude gas temperature and cold gas efficiency is analyzed and calculated,and the best working condition is obtained,which can provides a theoretical reference for the reasonable choice of coal gasification parameters.Secondly,the Aspen plus software was used to build the gas purification system at normal temperature,and the parameters of the clean gas under the best working condition were obtained.It is very important to improve the efficiency of the whole IGCC system that improve the efficiency of gas turbine and combined cycle.The study is based on an integrated coal gasification combined cycle power generation system that has been authorized by Prof.Fu Zhongguang.Power island adopts high pressure gas turbine reheat combined cycle system.The system is equipped with a two-stage compressor and an intercooler,and a reheat combustion chamber is added.The gas turbine is divided into two parts:high pressure and low pressure.The high pressure gas turbine reheat cycle system,HRSG and steam turbine system model are established by using Aspen plus software.By calculating the gas turbine efficiency of the system is up to 40.96%,and the output power of the gas turbine is 581 MW.The combined cycle efficiency can reach 59.18%.It is nearly 3 percentage points higher than the combined cycle efficiency of the ordinary 9F grade gas turbine.To simulate the different working conditions,The influence of intercooler outlet air temperature,maximum pressure and reheat pressure on the output power and efficiency of gas turbine and IGCC system was obtained and the optimal operating conditions were obtained.It provides a theoretical basis for parameter selection and structure optimization of high pressure gas turbine reheat cycle system and IGCC system.Thereby the output power and system efficiency of the IGCC power generation system are improved.