Five typical Chinese coals with different ranks were sampled,then their pyrolysis reaction heats were measured,in which TG-DSC was used to measure the heat flows of coal samples during pyrolysis process,and heat flow baseline was isolated or determined by empirical method and test method,respectively.Besides,the effects of pyrolysis temperature and coal rank on the coal pyrolysis reaction heat were investigated,and the pyrolysis reaction heats derived from different heat flow baseline determination methods were compared and discussed.Results show that the pyrolysis reaction heat of Shengli lignite,Shenmu long frame coal,Shendong bitumite,Datong bitumite and Taixi anthracite at a pyrolysis temperature of 1100 ℃ measured by test method were-5743.11,-13888.42,-16246.20,-21 433.89and 3097.79 J/g,respectively,whereas based on empirical method the pyrolysis reaction heat of these coals were -5963.81,-13839.86,-17792.50,-22871.74 and 3536.47 J/g,respectively.For coal samples excluding anthracite,with the increasing degree of coal metamorphism,the heat released during coal pyrolysis shows an increasing trend,also the pyrolysis reaction heat increases and then decreases and then increases again with the increase of pyrolysis temperature.For Taixi anthracite,the reaction heat is always positive at each temperature range,which means that the pyrolysis reaction of anthracite is endothemic,also the reaction heat is proportional to the pyrolysis temperature.The values of pyrolysis heats measured by two methods,empirical baseline method and test method,are close except Shendong bitumite and Datong bitumite.The biggish difference between pyrolysis reaction heats of Shendong bitumite and Datong bitumite determined by empirical baseline method and test method might result from the excessively higher reaction heat of two coals in the exothermic range predicted subjectively by empirical method when determining the baseline.Thus,it is obvious that the test method has the advantage of simpler operation,higher accuracy and better repeatability in the measurement of coal pyrolysis reaction heat than the empirical baseline method.%选取5种不同变质程度的煤样,利用TG-DSC同步联用仪测定煤热解过程的热流,并分别采用经验法和实验测定法确定热流基线,解析获得了煤热解反应热.此外,还考察煤阶及热解温度对煤热解反应热的影响,对比、分析两种基线确定法测定煤热解反应热的准确性.结果表明,1100℃热解温度下胜利褐煤、神木长焰煤、神东烟煤、大同烟煤以及太西无烟煤基于实验法确定热流基线所测得的热解反应热分别为-5743.11,-13888.42,-16246.20,-21433.89,3097.79 J/g,基于经验法确定热流基线所得的煤热解反应热分别为-5963.81,-13839.86,-17792.50,-22871.74,3536.47 J/g;除无烟煤外的其他煤样,随着煤变质程度的增大,煤热解过程中放出的热量总的来说呈现出增加趋势,有热解反应热随温度的升高先增大后降低再增大的规律;太西无烟煤在各温度下的热解反应热均大于零,一直表现为吸热反应,净吸热量也随温度的升高而增加;除神东烟煤和大同烟煤外,经验法确定热流基线和实验测定热流基线两种方法所测的煤热解反应热较为接近,神东烟煤和大同烟煤出现较大差异的原因是经验基线法依赖主观经验过高地预测了放热区间的反应热.在测定煤热解反应热过程中实验测定法具有操作简单、测定准确、实验可重复性强等优势.
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