当前煤的化学链燃烧中煤主要通过以下3步进行转化:煤的热解、煤焦的气化以及煤热解和气化产物与氧载体的反应。由于煤焦的气化反应速率较低,燃烧转化全过程受限于较慢速的煤焦气化过程,导致燃烧效率和CO2捕集效率的下降。化学链氧解耦燃烧采用具有吸释氧能力的氧载体,煤焦可以与氧载体释放的气态氧直接反应而转化,避免较慢速的煤焦气化过程,显著提高燃料的转化速率。运用AspenPlus软件构建了以CuO/Cu2O为氧载体的600MW化学链氧解耦燃煤发电系统。基于系统仿真结果,分别进行了能量、㶲和㶲成本分析。结果表明:化学链氧解耦燃煤发电系统的净热效率为37.66%;系统中内部㶲损失最大的组件为燃烧反应器,占子系统总内部㶲损失的44.23%。仅以发电量为产品时,化学链氧解耦燃煤发电系统的㶲效率为36.27%;如果将高浓度CO2也作为产品,系统的㶲效率为40.47%;化学链氧解耦燃煤发电系统中单位㶲成本最大的组件为第7台给水加热器,其次为第5个低压汽轮机、凝汽器、第1个高压汽轮机和空气预热器。

At present, the chemical looping combustion of coal comprises of the following three steps: coal pyrolysis, coal chargasification,and the reaction of coal pyrolysis and gasification products with oxygen carrier. The entire combustion conversion process islimited by the slower coal coke gasification process,which lead to a decrease in combustion efficiency and CO2 capture efficiency. Becauseof the oxygen carrier used in chemical looping oxygen uncoupling combustion with the ability to absorb and release oxygen,coal cokedirectly react with the gaseous oxygen released by the oxygen carrier,avoiding the slower coal coke gasification process and significantlyimproving the fuel conversion rate. This paper builds a 600 MW chemical linked oxygen decoupling coal-fired power generation systemusing CuO/Cu2O as oxygen carrier using Aspen Plus software. Based on the simulation results of the system,energy,exergy,and exergycost analyses were conducted separately. The results show that the net heat efficiency of the chemical looping oxygen uncoupling coal-firedpower generation system is 37.66%; The component with the highest internal exergy loss in the system is the combustion reactor,whichaccounts for 44.23% of the total internal exergy loss in the subsystem. When only the power generation is used as a product,the efficiencyof the chemical looping oxygen uncoupling coal-fired power generation system is 36.27%. If high concentration CO2 is also used as aproduct, the efficiency of the system is 40.47%. In the chemical looping oxygen uncoupling coal-fired power generation system, thecomponent with the largest unit exergy cost is the seventh feedwater heater,followed by the fifth LP turbine,condenser,the first HPturbine and air preheater.

0 引言

1 CLOU电厂系统建模

2 结果与讨论

   2.1 系统能量分析

   2.2 系统㶲分析

   2.3 系统的㶲成本分析

3 结论