Simulation And Optimization Of The Huaneng Tianjin IGCC Power Station

With the improvement of China’s economy and industry,the demand of electricity is increasing.Thermal power generation is the main force of energy.And China’s thermal power generation is gradually transforming into a low-carbon,clean and high efficiency,during the period of the Peak Carbon Dioxide Emission and Carbon Neutrality.Integrated Gasification Combined Cycle（IGCC）is efficient and clean thermal power generation technology.Therefore,it is necessary to stimulate and optimize Huaneng Tianjin 250MW IGCC demonstration power station using the softwares of Aspen Plus and Fluent.Firstly,the IGCC system is stimulated by Aspen Plus.The IGCC system includes three parts.The air separation system（ASU）adopts low pressure independent equipments using multi-effect distillation columns and heat exchangers.The gasification and purification system uses Gibbs reactors and Rstoic reactors to stimulate combustion and gasification.The gas-steam combined cycle system uses Heat X heat exchangers and Rstoic reactors to syngas,turbine and heat recovery.The parameter error is less than 5%compared with the operating results of the power station.The model of 250MW IGCC is accurate and realiable.Secondly,two-stage entrained-flow coal gasifier is stimulated by Fluent.The optimization of ASU affect oxygen purity,and oxygen purity significantly affect the temperature,syngas composition.The carbon conversion rate quantitatively describes gasification reaction.The DPM model,P1 model and EDC model are used.The oxygen purity decreases,the outlet temperature of the gasifier decreases,and the purity of CO and H₂ decreases.When the oxygen purity is 95%,the reduced temperature slightly reduces gasification reaction.However,the purity of the effective syngas components is reduced by 1%,the carbon conversion rate is reduced by 2.1%.To sum up,the slightly reducing oxygen purity has little effect on the gasification reaction.And the oxygen purity of 95%is suitable for the gasifier to work.Finally,optimize the IGCC system to reduce energy consumption.The energy consumption of ASU accounts for 70%of power station self-consumption.It is necessary to optimize ASU to save energy adopting methods such as partial integration,nitrogen re-injection,and reduction of oxygen purity.The power supply efficiency first increases and then decreases as the integration coefficient increasing.When the integration coefficient is 0.7,the power supply efficiency is the highest.High-pressure nitrogen re-injection can reduce the amount of water vapor.When the re-injection coefficient is 0.6,19.25 t water vapor can be saved per hour and the economic benefit is improved.As the compressor outlet pressure drops,the oxygen purity is decreased.Then the minimum separation work decreases.For the coal gasification and purification system,start to simulate process to select the optimal gasification parameters.The oxygen-coal ratio is 0.6～0.7,the steam-coal ratio is 0.08～0.13,the gasification pressure should lower than 40bar,and the oxygen purity should be selected at about 95%.The above optimization method is coupled into the IGCC model.The power supply efficiency increases by 0.3687%compared the previous moedel.The optimization measures such as partial integrated air separation,oxygen purity reduction by 5%are effective.A reference scheme is proposed for the overall optimization of IGCC system.