【作者】 段天宏；

【导师】 王作棠；

【作者基本信息】 中国矿业大学 ， 采矿工程， 2014， 博士

【摘要】 煤炭气化指标无论是对地面气化还是地下气化，都尤为重要，它为气化及其后续工艺的工艺设计和工程设计提供最原始的基础数据。本文首次实现了600℃以上的温压状态下的原位煤热解实验，建立了模拟煤炭地下气化过程中煤炭热解的实验方法，得到了温压状态下的原位煤热解产气规律：1）随着应力的增加，产气率和半焦（焦）产率增加，但焦油产率下降；2）随着应力的增加，热解气中的CH4和CO2含量增大，H2、CO含量减小；3）无论是产气率、焦油和半焦（焦）产率还是各气体含量在应力作用下的变化需要在超过一定的温度之后才能显现出来；4）热解煤气中C2H6含量在800℃附近有一个峰值点，超过这个峰值点后C2H6含量曲线急剧下降。在这个峰值点之前，C2H6含量随应力增大而增大，但是超过这个峰值点之后，C2H6含量随应力增大而减小；C2H4含量在600℃~1000℃之间随应力的增大而增大，曲线在750℃~800℃之间增长缓慢，但在800℃之后迅速增长；C3H8含量在600℃~1000℃之间随应力增大而减小；5）从单位应力导致的产气率、焦油产率和半焦（焦）产率以及各气体含量的变化值来看，挥发分高的煤种在各个温度点都相应要大一些；6）无应力状态下主要热解气组分H2、CO、CH4和CO2在800℃或者850℃就趋于平稳，而C2H6、C3H8和C2H4则在900℃才趋于平稳，各种应力状态下的各气体组分的变化曲线形态与无应力状态下的变化曲线基本类似，但是C2H6、C3H8和C2H4含量在各应力状态下在超过900℃的高温下变化非常显著，表现出与无应力状态下不同的规律。在此基础上，本文建立了一个煤炭地下气化指标的两段式反应平衡计算法，并应用matlab编制了煤炭地下气化的空气蒸汽连续法、富氧蒸汽连续法和纯氧蒸汽连续法的气化指标计算程序。应用计算出来的气化指标对现场试验的设计进行了模拟。计算结果与稳定后的实际现场试验数据吻合度非常高，证明模型和程序能够很好地对煤炭地下气化进行模拟。本文还建立了二氧化碳回炉的煤炭地下气化指标的两段式反应平衡计算法，进行了纯氧蒸汽二氧化碳连续法和空气蒸汽二氧化碳连续法的煤炭地下气化的气化指标计算。模拟中发现：二氧化碳相对于水蒸汽来说是一种更快调节气化炉温度的气化剂；二氧化碳部分代替了水蒸汽。本文提出煤炭气化指标中应该包含综合气化效率和热煤气综合气化效率这两个指标作为煤炭气化过程能量转化效率的评价指标并给出了相关计算方法。实例情境下的纯氧蒸汽二氧化碳连续法煤炭地下气化的冷煤气效率要比德士古气化高出6.48个百分点，综合气化效率要比德士古气化高出10.56个百分点，热煤气综合气化效率要比德士古气化高出11.28个百分点。在其它条件一定的前提下，气化剂中汽（二氧化碳）氧比直接决定着气化炉能量转化效率，各工艺条件下都有一个最优的汽（二氧化碳）氧比。计算结果表明，一定量的二氧化碳的加入对于提高煤炭地下气化的综合气化效率和热煤气综合气化效率都是有利的，而一定量纯氧的加入对于提高煤炭地下气化的综合气化效率是有利，但是对于提高煤炭地下气化的热煤气综合气化效率并无直接的关系。本论文有图115幅，表56个，参考文献210篇。更多还原

【Abstract】 Coal gasification indexes are important for either ground gasification orunderground gasification. That’s because the most primary essential data can beobtained from Coal gasification indexes for the process design and engineering designof gasification and its follow-up processes.It is the first time to conduct the in-stiu coal pyrolysis experiment under warmpressure state which has a temprature of above600℃. An experimental method isestablished to simulate coal pyrolysis during the process of underground coalgasification. Then, the common law of pyrolysis coal gas production of Coal underwarm pressure state was obtained as list.1) Along with the increase of stress, gas production rate and semicoke (coke)production rate increase, but tar yield decreases.2) Along with the increase of stress, the content of CH4and CO2in pyrolysis gasincreases and that of H2and CO decreases.3) Both gas production rate, tar production rate and semicoke (coke) productionrate as well as the content of each gas under the stress change can be displayed onlywhen exceeding certain temperature.4) The content of C2H6involves peak temperature nearby800℃and sharplyreduces after exceeding this peak point. Before the peak point, the content of C2H6increases along with stress increase. After the peak point, that of C2H6decreases alongwith stress increase. The content of C2H4increases along with stress increase. Thecurve slowly grows between750℃and800℃. However, it increases rapidly after800℃. The content of C3H8decreases along with stress increase between600℃and1000℃.5) From the gas production rate, tar production rate and semicoke (coke)production rate caused by unit stress as well as the change value of each gas content,it can be concluded that the value of Coal which has higher volatile matter isrelatively higher than that of lower under each temperature.6) Under no-stress state, the main pyrolysis gas components including H2, CO,CH4and CO2tend to go steady at800℃or850℃. But hydro carbons including C2H6,C3H8and C2H4tend to go steady at900℃. The changing curve patterns of each gascomponent under various stress states are fundamentally similar with that underno-stress state. Yet, there are very remarkable changes in the contents of C2H6, C3H8and C2H4under various stress states when exceeding the high temperature of900℃, which shows the laws different from that under no-stress state.Based on the above, two-stage reaction equilibrium calculation method ofunderground coal gasification was established in this thesis. In addition, matlab wasemployed to compile the calculation procedures of air steam continuous method,oxygen-enriched continuous method and pure oxygen steam continuous method ofunderground gas gasification. Meanwhile, these calculation procedures were appliedto simulate the gas production process of field test..Computaion results have providedthe guidance for the design of field test. The matching degree of calculated results andactual field test data after stabilization is very high, which proves that the model andprocedures can make good simulation for underground coal gasification.The two-stage reaction equilibrium calculation method of underground coalgasification index of carbon dioxide remeltting was established to calculate theunderground coal gasification indexes with pure oxygen steam carbon dioxidecontinuous method and air steam carbon dioxide continuous method. Computaionresults suggest that carbon dioxide is a kind of gasification agent enabling to quicklyadjust gasifier temperature compared with water vapor and carbon dioxide partlyreplaces water vapor.In this thesis, two indexes of coal gasification index including comprehensivegasification efficiency and hot gas comprehensive gasification efficiency wereproposed as evaluation index of energy conversion efficiency in the process of coalgasification. Besides, relevant computing methods were given. In terms of pureoxygen steam carbon dioxide continuous method under living example, cold coal gasefficiency of underground coal gasification is higher than that of Texaco gasificationby6.48%, comprehensive gasification efficiency of underground coal gasification ishigher than that of Texaco gasification by10.56%, hot gas comprehensivegasification efficiency of underground coal gasification is higher than that of Texacogasification by11.28%. Under the premise of other fixed conditions, the ratio ofsteam(carbon dioxide) to oxygen in gasification agent directly determines the energyconversion efficiency of gasifier. There is optimal ratio of steam(carbon dioxide) tooxygen under various technological conditions. The calculation results indicate thatadding a certain amount of carbon dioxide is beneficial for improving comprehensivegasification efficiency and hot gas comprehensive gasification efficiency ofunderground coal gasification. However, adding a certain amount of pure oxygen isuseful for enhancing comprehensive gasification efficiency of underground coal gasification. However, it is irrelevant to reinforce hot gas comprehensive gasificationefficiency of underground coal gasification.There are115figures,56tables and210references.更多还原