Abstract: Coal chemical industry is noted for high energy consumption and significant discharge of CO₂. Using thermodynamic analysis to evaluat utilization of energy in such processes can effectively find defects of energy utilization and energy-saving potential,and can provide the basis for energy saving optimization reconstruction of the process. Thermodynamic analysis includes energy balance and exergy analysis. This paper presents the method of combining entropy analysis with exergy analysis after reviewing the traditional analysis methods and pointing out their shortages. Taking Texaco coal gasification as an example,energy utilization was analyzed by using energy balance,exergy analysis and the proposed method. Energy consumption,entropy generation and distribution of exergy loss of all modules were obtained. Based on this,the relationship between exergy loss and CO₂ emission was established,and distribution of CO₂ emission and exergy loss coefficient of all modules were obtained by calculation. The gasifier was the main location for energy-saving. This relationship we established could provide theoretical basis for energy saving and emission reduction of the coal gasification process.

Key words: coal gasification, entropy generation, exergy loss, CO₂ emission

摘要： 煤化工是高耗能高CO₂排放的工业,利用热力学分析方法对其工艺过程中能量利用情况进行分析,可以有效地发现工艺的能量利用缺陷和节能潜力,为过程的节能优化改造提供依据.目前热力学分析方法主要包括能量衡算法和(火用)分析法,本文在对传统热力学方法进行分析和评价的基础上,指出了已有方法的不足,提出了新的熵(火用)分析相结合的分析方法,并以德士古煤气化工艺为例,分别使用传统的能量衡算法、(火用)分析法和本文提出的熵(火用)结合分析法对工艺过程的能量利用情况进行了分析,获得了工艺过程中内各模块的能量、熵增和(火用)损分布.在此基础上,将(火用)损与工艺过程中CO₂排放量建立联系,经过计算得到了工艺过程中各个设备对应的CO₂排放分布和(火用)损系数,得出气化炉是工艺过程中主要的节能位置.这种能量与CO₂排放的关联能为工艺过程的节能减排提供理论依据.

关键词: 煤气化, 熵产, (火用)损, CO₂排放量