我国能源结构呈现“富煤缺油少气”的特点，以煤气化技术为核心的天然气动力多联产系统在我国有广泛的应用前景。然而目前基于传统气化技术构建的煤基多联产系统在能源利用效率进一步提升方面存在限制。以水蒸气气化工艺为核心，集成了带有热化学回热单元的、高效的串并联综合型天然气动力多联产系统，并在Aspen Plus中搭建了系统模型，基于热效率、相对节能率(火用)效率等指标分析了该系统的能量利用特性。结果表明，与基于传统气化的天然气动力多联产系统相比，新系统的热效率和(火用)效率分别提升了5.5%、5.8%。同时，对于不同的分流比存在最佳的化工岛未反应气循环倍率使系统热力性能最优，分流比为0.5、0.7、0.9、1.0时，对应的最佳循环倍率分别是4.8、4.4、4.3、4.0；串联型多联产较串并联综合型多联产系统能更合理地利用能量，串联型多联产系统在最佳循环倍率时的热效率、相对节能率和(火用)效率分别达到68.06%、20.24%、69.43%；(火用)分析表明，该系统(火用)损失最大的部分主要分布在气化单元和联合循环单元，两项损失分别为17.0%、6.3%，占比分别达到总(火用)损失的49.4%、18.3%。基于热化学回热型水蒸气气化技术的多联产系统，具有较高的能量利用效率和碳减排效果，可以为煤的高效低碳利用提供一种有效的节能方式。

The energy structure is characterized by “more coal,less oil and gas” in China,the Synthetic Natural Gas(SNG）and power polygeneration system with coal gasification technology as the core has wide application prospects in China. However,the coal based polygeneration system based on traditional gasification technology has limitations in further improving energy efficiency. Based on the coal-steam gasification technology,this article integrates an efficient series-parallel SNG and power polygeneration system with a thermochemical recuperation unit. The system model was built in Aspen Plus software. Based on indicators such as thermal efficiency,energy saving ratio and exergy efficiency,the energy utilization characteristics of the system were analyzed. The results show that compared with the SNG and power polygeneration system based on traditional gasification,the thermal efficiency and exergy efficiency of the novel system have been improved by 5.5% and 5.8%,respectively. At the same time,for each set split ratio,there is a best chemical island unreacted syngas recycle ratio to optimize the thermodynamic performance of the system. When the split ratio is 0.5,0.7,0.9,1.0,the corresponding optimal recycle ratio is 4.8,4.4,4.3,4.0 respectively. Also,the series polygeneration system can use energy more reasonably than the series-parallel polygeneration system,and the thermal efficiency,energy saving ratio and exergy efficiency of the series polygeneration system at the optimal recycle ratio can reach 68.06%,20.24%,69.43% respectively. Exergy analysis shows that the two largest parts of the system exergy destruction are mainly distributed in the gasification unit and combined cycle unit,the exergy destruction of the two parts are 17.0% and 6.3% respectively,accounting for 49.4% and 18.3% of the total exergy destruction,respectively. Therefore,polygeneration system based on thermochemical regenerative steam gasification technology has high energy utilization efficiency and carbon emission reduction effect,and can provide an effective energy-saving way for high-efficiency and low-carbon utilization of coal.

0 引言

1 多联产系统模型的建立

   1.1 合成气制备单元

   1.2 SNG合成单元

   1.3 联合循环单元

2 结果及讨论

   2.1 多联产系统的评价指标

   2.2 循环倍率对系统热效率和相对节能率的影响

   2.3 循环倍率对系统(火用)效率的影响

3 结论