基于Aspen Plus的循环流化床工业气化炉模拟

摘要

循环流化床煤气化炉在工业应用过程中,由于试验煤种及操作条件的多样性,通过试验法优化操作过程所需周期较长、成本较大.因此以大量工程数据为边界条件,基于 Gibbs 自由能最小化原理,利用 Aspen Plus对气化过程进行模拟,通过灵敏度分析,研究了单因素氧煤比、蒸汽煤比、气化压力、空气/蒸汽预热温度变化对气化指标的影响;并运用正交实验,研究了以上4种因素共同作用的结果.研究结果表明:氧煤比增加使有效气(CO+H2)含量、冷煤气效率先增加再减小,并在0.45~0.50kg/kg 时取得最大值;蒸汽煤比增加使煤气热值和气化温度减小,对有效气含量基本没有影响;气化压力增加使煤气热值和气化温度增加;空气/蒸汽预热温度增加使气化温度、有效气含量、冷煤气效率增加,煤气热值减小.通过正交实验综合分析,氧煤比和空气/蒸汽预热温度对气化指标的影响较为显著,两者对气化指标的影响趋势基本一致;蒸汽煤比主要影响煤气热值,而气化压力主要影响比氧耗,对其他指标影响较小.%In the process of industrial circulating fluidized bed gasification,experimental research is time-consuming and cost-consuming due to the diversity of coal types and operating conditions. A circulating fluidized bed gasifier model was developed by Aspen Plus based on Gibbs free energy minimization. The boundary conditions of the simulation were set in terms of existing industry data. Different factors in gasification process were investigated,including oxygen-coal ratio,stream-coal ratio,gasification pressure and air/stream preheating temperature. The orthogonal experiments were used to study the interactive effect of the four factors. The results showed that the gasification product (CO+H2) content and cold gas efficiency increase first and then decrease with oxygen-coal ratio increasing. The optimal range of oxygen-coal ratio is 0.45—0.50kg/kg. The gas heating value and gasification temperature decrease with the increase of stream-coal ratio. However,the gasification product content is hardly affected by stream-coal ratio. The gas heating value and gasification temperature increase with gasification pressure increasing. The gasification temperature,gasification product content and cold gas efficiency increase with air/stream preheating temperature increasing, while gas heating value decreases with air/stream preheating temperature increasing. The oxygen-coal ratio and air/stream preheating temperature have significant influence on gasification index,and they also have the same impact on gasification index through orthogonal experiment. The stream-coal ratio mainly affects gas heating value,while gasification pressure has significant influence on oxygen consumption rate.