煤/钙基载氧体化学链燃烧操作参数分析

化学链燃烧作为一种新颖的燃烧技术,在化石燃料燃烧释放能量的同时能够有效分离CO2。今以CO2为气化剂气化煤炭,基于Aspen Plus流程模拟软件,研究了煤/钙基载氧体化学链燃烧过程。结果表明,以CO2为煤气化剂,各反应器含水分少,可减少热损失。CaSO4载氧体具有载氧能力大以及反应活性良好等优点。气化炉中CO+H2含量随二氧化碳煤比增大逐渐增加后下降;随温度升高其含量先增加,后趋于平稳。燃料反应器中CO2+H2O含量随载氧体煤比增大,呈现先增大后减小的趋势;随温度升高其含量逐渐下降。空气反应器中CaSO4含量随空载比增大先增加后趋于平稳,随温度升高其含量趋于平稳后下降。气化炉中硫化物和氮化物含量随温度升高而下降,而燃料反应器和空气反应器中硫化物含量随温度升高增加趋势明显,氮化物含量变化不明显。最后确定了关键反应器操作参数:气化炉的二氧化碳煤比为1.8;燃料反应器的载氧体煤比为4.5;空气反应器的空载比为10.5和三反应器的操作温度分别为950、1000和1100℃。

Operating Parameters Analysis of Chemical-Looping Combustion (CLC) with Coal/Ca-Based Oxygen Carrier

As a new attractive technology,the chemical-looping combustion(CLC) can separate and capture the CO2 produced by the combustion of fossil fuels during the energy production.Using CO2 as gasifying agent,the chemical-looping combustion with CaSO4 as oxygen carrier was investigated by Aspen Plus software in this paper.The use of CO2 as gasifying agent is characterized by less heat loss of the system because of the lower amount of steam in the gaseous products produced in the reactors,and the oxygen carrier CaSO4 used has high reactivity with high oxygen carrying capacity.In the gasification reactor,with the increase of C2C(CO2/coal ratio),the amounts of CO and H2 in the syngas increase gradually,and then decrease greatly.With the rise of the gasification temperature,the contents of CO2 and H2 in the syngas increase at first,and then remain constant;however,the contents of sulfides and nitrides decrease obviously.In the fuel reactor,with the increase ofψO2C(CaSO4/coal ratio),the mole fraction of CO2 and H2O increase firstly,and then decrease;and with the rise of the reaction temperature,the contents of CO2 and H2O in the flue gas from the reactor decrease gradually.In the air reactor,with increasing A2C(air/CaSO4 ratio),the mole fraction of CaSO4 produced increases at first and then tends to maintain a steady value;and with the rise of the temperature,the amount of product CaSO4 keeps unchanged firstly,and then decreases slowly.Moreover,with the increase of temperature,the contents of sulfides in fuel reactor and air reactor increase obviously,and the content of nitrides almost keep constant.Finally,the operating parameters of the system were determined as follows: the C2C(CO2/coal ratio) of the gasifier is 1.8;the O2C(CaSO4/coal ratio) of the fuel reactor is 4.5;the A2C(air/CaSO4 ratio) of the air reactor is 10.5,and the favorable operating temperature for the three reactors are 950℃,1000℃ and 1100℃,respectively.