基于化学计量理论的煤炭地下气化过程能量回收评价方法

Energy recovery evaluation method of underground coal gasification process based on stoichiometry theory

煤炭地下气化(UCG)过程的能量回收评价对整个煤炭地下气化过程的有效控制具有十分重要的意义。评价内容包括对气化耗煤量、煤气产率及速率、气化产物热值及气化效率等煤炭地下气化成效评价所需关键参数的设计、监测、计算和解析。通过对选定煤样进行UCG模拟试验,研究了不同链接孔方法和操作参数所产生的影响,建立了基于化学计量理论的能量回收评价方法,并定义了能量回收率。试验结果表明,链接孔模型所产生的生成气平均热值高达10.26 MJ/m^(3)(V形通道)和11.11 MJ/m^(3)(L形通道);而同轴孔模型试验结果分别为7.38和4.70 MJ/m^(3);气化后链接孔模型试验的空腔体积约为同轴孔模型试验的2倍;研究结果表明,气化通道类型和气化剂流量会影响煤炭消耗量和生成气热值;链接孔气化通道类型对气化区后续气化燃烧的氧化表面和破坏裂隙的发育有很大影响;本研究提出的基于化学计量法的气体能量回收评价方法简单可靠,计算结果与实际测试值的误差在10%以内,可有效评估气化过程中的气化煤量、煤气产量及热值等。

The evaluation on the energy recovery of underground coal gasification(UCG)process is of great significance to the effective control of entire underground coal gasification process.The evaluation includes the design,monitoring,calculation and analysis of key parameters required for the evaluation of underground coal gasification,such as coal consumption,coal gas production rate and rate,calorific value of gasification products and gasification efficiency.In this paper,through UCG simulation experiment on selected coal samples,the influence of different linking hole methods and operation parameters are studied,and the evaluation method of energy recovery based on stoichiometry theory is established,and the energy recovery rate is defined.The experimental results show that the average heat value of the gas generated by the linked hole model is 10.26 MJ/m^(3)(V-shaped channel)and 11.11 MJ/m^(3)(L-shaped channel).The experimental results of the axial hole model were 7.38 MJ/m^(3)and 4.70 MJ/m^(3).The cavity volume of the link hole model experiment after gasification is about twice that of the coaxial hole model experiment.The results show that the type of gasification channel and the flow rate of gasification agent affect the coal consumption and the calorific value of generated gas.The type of linked hole gasification passage has great impact on the development of oxidation surface and fracture of subsequent gasification combustion in gasification zone.The evaluation method of gas energy recovery based on stoichiometry proposed in this study is simple and reliable,and the error between the calculated results and the actual measured values is within 10%,which can effectively evaluate the amount of coal gasification,coal gas production and calorific value in the gasification process.