化工进展 ›› 2021, Vol. 40 ›› Issue (7): 3719-3727.DOI: 10.16085/j.issn.1000-6613.2020-1626

• 能源加工与技术 • 上一篇    下一篇

煤制天然气过程全局能量集成优化

刘阳1,2,3(), 吴秀章4, 刘永健3(), 王波3   

  1. 1.辽宁大唐国际阜新煤制天然气有限责任公司,辽宁 阜新 123000
    2.华南理工大学,广东 广州 510641
    3.中新能化科技有限公司,北京 100084
    4.中国大唐集团有限公司,北京 100032
  • 收稿日期:2020-08-13 修回日期:2020-09-21 出版日期:2021-07-06 发布日期:2021-07-19
  • 通讯作者: 刘永健
  • 作者简介:刘阳(1989—),男,博士,研究方向为煤化工过程系统优化。E-mail:celiuyang@126.com
  • 基金资助:
    国家自然科学基金重点项目(21736004)

Global heat integration and optimization of coal to natural gas process

LIU Yang1,2,3(), WU Xiuzhang4, LIU Yongjian3(), WANG Bo3   

  1. 1.Liaoning Fuxin Coal-Natural Gas Datang International Corporation Ltd. , Fuxin 123000, Liaoning, China
    2.South China University of Technology, Guangzhou 510641, Guangdong, China
    3.Zhongxin Energy & Chemical Co. , Ltd. , Beijing 100084, China
    4.China Datang Group Corporation Ltd. , Beijing 100032, China
  • Received:2020-08-13 Revised:2020-09-21 Online:2021-07-06 Published:2021-07-19
  • Contact: LIU Yongjian

摘要:

我国正在大力发展煤制天然气项目实现清洁能源供给。然而现有煤制天然气示范项目存在能耗大、CO2排放高、生产成本缺少竞争力的问题。本文从煤制天然气能量系统出发,通过全局能量集成实现煤制天然气项目的节能减排与经济效益的提高。根据煤化工示范项目特点,提出了煤制天然气过程全厂能量系统集成优化策略:建立了煤制天然气各单元过程模型,对全流程的物流和能流展开了详细的模拟计算;利用夹点技术对全厂内各单元过程的能量系统展开了用能分析;利用全局温焓曲线对全厂能量系统进行了分析,揭示出全厂能量利用效率低是由于高品位热量降质利用和低品位余热未得到合理利用引起的。通过装置间热回收集成和增设有机朗肯余热回收装置可有效地提高热回收率。通过全厂能量系统优化集成,燃料煤消耗由现有过程1.26t/kNm3(0℃、101325Pa标准状态)天然气下降到1.07t/kNm3天然气。由于公用工程系统消耗的减少,全厂能量利用效率由原来的57.2%提高到59.6%,同时CO2排放可以由原来5.02t/kNm3天然气下降到4.66t/kNm3天然气。相比于现有过程,改进过程的总投资仅增加了2%左右,而单位生产成本由1.65CNY/Nm3下降到了1.59CNY/Nm3,对于年产20亿立方米煤制天然气厂每年可节约生产成本1.2亿元。

关键词: 煤制天然气, 全局能量集成, 夹点技术, 温焓曲线, 技术经济分析

Abstract:

China is now vigorously developing coal-to-SNG process for clean energy supply. However, recent studies reveal that this process suffers from high energy consumption and greenhouse gas emissions. An effective way to solve it is to increase the plantwide energy efficiency by Total Site Heat Integration. The total site profile of coal-to-SNG reveals that the low temperature waste heat recovery and the heat integration between coal gasification unit and water gas shift unit could provide considerable energy savings. The total site analysis method was used to target the maximum heat recovery and the optimal site utility system. The results showed that the site utility consumption decreased from 1.26t/kNm3 to 1.07t/kNm3 SNG and the plantwide energy efficiency was increased from 57.2% to 59.6%. On the other hand, the CO2 emission decreased from 5.02t to 4.66t CO2 per kNm3 SNG. The water consumption of the integrated process decreased around 33.4% compared to that of the conventional process. Unit production cost decreased from 1.65 CNY/Nm3 SNG to 1.59 CNY/Nm3 SNG. Thus, an annual production cost of 120 million CNY could be saved for an annual production of 2×109 m3 natural gas.

Key words: coal-to-SNG, total site heat integration, pinch technology, temperature-enthalpy curve, techno-economic analysis

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