基于Aspen Plus的西部典型煤化学链气化模拟研究

Simulation study on chemical looping gasification of typical coal in Western China based on Aspen Plus

面对全球变暖,发展低能、低碳、环保的新型煤炭综合利用技术迫在眉睫。化学链技术是一种新型的化学转化和能源利用新技术。利用Aspen Plus软件建立化学链气化过程,模拟研究中试规模下,西部典型煤和煤中水分含量对化学链气化过程的影响,结合煤中组分与气化过程,分析不同煤种产生不同合成气含量的原因;并提出了模拟煤中不同水分的方法,分析水分如何影响化学链气化过程,为中试放大提供理论指导。结果表明,宁夏羊场湾煤(NX)和陕西神木煤(SX)的合成气产率(以煤计)高于2.0 Nm3/kg,冷煤气效率高于0.9。云南昭通煤(YN)合成气产率低于1.0 Nm3/kg,冷煤气效率最低,合成气产率和冷煤气效率为:NX>SX>新疆伊犁煤(XJ)>内蒙鄂尔多斯煤(NM)>YN;因水分会增加水蒸汽带走热量,煤中水分含量越高越不利于气化。煤中含水量从22.38%降到0时,合成气产率增大,冷煤气效率增大了34.5%。气化反应器所需热量降低了8.89%。因此,为得到更多的合成气,尽量选择固定碳高、水分少及挥发分低的煤种作为原料;在煤进入气化炉前增设干燥装置,提高合成气产率和冷煤气效率。

In the face of global warming,it is urgent to develop new comprehensive utilization technology of coal with low energy,low carbon and environmental protection.Chemical looping technology is a new technology of chemical conversion and energy utilization.Aspen Plus software was used to establish the chemical looping gasification process.The influence of typical coal and moisture content on chemical looping gasification process in western China was simulated on a pilot scale.Combined with the coal composition and gasification process,the reasons for different syngas content produced by different coal types were analyzed.The method to simulate different moisture content in coal was proposed to analyze how moisture affects chemical looping gasification process,which provided theoretical guidance for pilot scale enlargement.The results show that the syngas yield of coal of Yangchangwan Coal in Ningxia(NX)and Shenmu coal in Shaanxi(SX)is higher than 2.0 Nm 3/kg(coal),and the cold gas efficiency is higher than 0.9.The syngas yield from coal of Zhaotong coal in Yunnan(YN)is lower than 1.0 Nm 3/kg(coal)and the cold gas efficiency is the lowest.The syngas yield and the cold gas efficiency are as follows:NX>SX>Yili coal in Xinjiang(XJ)>Erdos coal in Inner Mongolia(NM)>YN.Because moisture increases steam and carries away heat,the higher the moisture content in coal is,the worse the gasification is.When the water content in coal drops from 22.38%(wt)to 0,the yield of syngas increases and the efficiency of cold gas increases by 34.5%.The heat required for gasification reactors is reduced by 8.89%.Therefore,in terms of raw material selection,in order to get more syngas,coal with high fixed carbon,less moisture and low volatile matter should be selected as raw material.The drying device is added before the coal enters the gasifier to improve the yield of syngas and the efficiency of cold gas.