Simulation on the Cal System with Dual Fluidized Bed Reactor

The high-temperature calcium-based carbon capture system uses a dual fluidized bed reactor as a carbonization furnace and a calcination furnace.Flue gas enters the carbonization furnace and reacts with CaO for decarburization treatment, and the generated CaCO₃ is sent to a calciner for high-temperature calcination decomposition. High concentration of CO₂,which is condensed and compressed、storaged and utilized. In this paper, the Aspen plus software is used to optimize internal parameterization simulation of carbon capture system, simulate the carbon capture system integrated with the 600MW coal-fired power plant system, and research carbon capture system waste heat utilization.

For the optimization of the internal parameterization simulation of carbon capture system, including temperature,Ca/C ratio,etc.The results show: Under the condition of the CO₂ capture rate is more than 90%, simulated the optimal temperature is 635℃,and carbon capture efficiency decreased as carbonization temperature increasing. The Ca/C molar ratio was 3.9, and change of carbon capture efficiency was not obvious with increase of Ca/C molar ratio.

Through the simulation of the carbon capture system integrated with the 600MW unit coal-fired power plant system, four units including coal combustion,carbon capture system, air separation,steam turbine and power generation,etc.The results show：Heat release of carbon capture system integrated with coal-fired power plant system flue gas and CO₂ condensation is 601.203MW,air separation unit consumes energy of 171.64MW.

For waste heat utilization, the waste heat of the flue gas is used to heat cold air entering the coal-fired boiler and boiler condensed water for steam turbine power generation, and heat release of CO₂ condensation is all used to heat the CaCO₃ into calciner. The results show:the net efficiency of the power plant increases with the proportion of waste heat used to heat the cold gas, and CO₂ condensation can reduce the energy of air separation unit by 195.5 MW.

The significance of the research in this paper is to carry out the carbon capture system and integrated simulation between the systems, provide data help for the actual application of the system, supply a good theoretical foundation, save the time consumed in actual application of the system, and reduce possibility of system error.Subsequent research includes optimization of integration between systems、optimization of utilization of waste heat and measures to improve system efficiency.