大型天然气蒸汽转化制氢工艺全流程模拟及优化

Simulation and optimization of large natural gas steam reforming process for hydrogen generation

利用Aspen Plus模拟计算软件对大型天然气蒸汽转化制氢工艺进行全流程模拟计算和分析。对全流程所含预处理、蒸汽转化、中温变换、CO_2脱除4个工艺单元及热回收、燃烧、蒸汽3个辅助系统逐一进行精细化模拟并有机整合。模型模拟得到关键流股的成分、主要工艺参数如下:热回收率93.0%,副产蒸汽量132.0 t/h,循环水消耗量1 080.0 t/h,燃料消耗量4 160 m^3/h。通过模型和计算模块对全流程换热网络进行优化。对优化后的模拟结果进行灵敏度分析表明:当水碳比增大时,转化炉出口CH_4含量、中温变换炉出口CO含量及原料消耗量均减少,而燃料消耗量、助燃空气消耗量及副产蒸汽量均增大。通过该模型,能够为工艺方案比选、优化设计及节能减排提供模拟和预测。

The large natural gas steam reforming process for hydrogen production is simulated with Aspen Plus. The pre-treatment, steam reforming, middle temperature shift, CO2 removal, heat recovery, combustion and steam generation units are modeled and integrated . The key stream compositions have been obtained. The main process parameters are as follows ： heat recovery percentage 93.0% , by-product steam production 132.0 t/h, cooling water consumption 1 080.0 t/h, and fuel consumption 4 160 m^3/h. The simulation results are analyzed for sensitivity. When the water to carbon ratio is increased, the CH4 at the outlet of reforming furnace and CO at outlet of MT shift furnace and feedstock requirement are reduced. Whereas, the consumptions of fuel and combustion air and steam production are increased. The model can provide simulation and prediction for process comparison, optimization design, energy saving and emission reduction.