氧化铁对煤流化床热解特性影响的实验研究
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摘要
为了分析Fe_2O_3对煤热解特性的影响,以准格尔烟煤为原料,在小型流化床反应器上,温度范围为500～800℃内,对添加Fe_2O_3质量分数分别为0%、5%、10%、20%的煤样进行热解,并对其热解产物产率和气体组分进行分析。结果表明:Fe_2O_3在整个温度范围内会明显降低焦油产率,却促进热解水的产生。Fe_2O_3对半焦和气体的影响特性与温度有关:在低温区,Fe_2O_3会催化胶质体的芳构化作用和缩聚反应,抑制胶质体的裂解反应,从而增加半焦产率,减小挥发分(热解气体和焦油)产率;而在高温区,半焦会和Fe_2O_3发生反应,使得CO和CO_2产率上升;另外,Fe_2O_3会明显改变热解气组分。温度较低时,Fe_2O_3会促进煤中的含氧自由基重新结合,抑制CO和CO_2的生成,随着温度的升高,Fe_2O_3与多种还原性气体(CO、H_2、CH_4)发生氧化还原反应,多种反应竞争下,使得Fe_2O_3对各气体的促进程度不同。
Zhungeer bituminous coal was selected as experimental materials in order to study the effect of Fe_2O_3 on pyrolysis characteristic of coal. The pyrolysis experiments of the raw coal loaded mass fraction of 0%, 5%, 10%, 20% of Fe_2O_3 were carried out in a small fluidized bed reactor, within the temperature range from 500 ℃ to 800 ℃.The results showed that, at the temperature range from 500 ℃ to 800 ℃,Fe_2O_3 could obviously reduce tar yield, but increase water yield. The effects of Fe_2O_3 on char and gas were relative to temperature. At the temperature between 500℃ and 600 ℃, Fe_2O_3 would catalyze the aromatization and polycondensation of the colloid and inhibit the cracking reaction of the colloid, thus increasing the char yield and reduce the volatiles(including gas and tar) yield. At the temperature between 700℃ and 800℃, the semi coke reacts with Fe_2O_3, therefore increasing CO and CO_2 yield. In addition, Fe_2O_3 would significantly change the pyrolysis gas components. When the temperature was low, Fe_2O_3 would promote the recombination of oxyradical, so the formation of CO and CO_2 was suppressed. And with temperature increasing, Fe_2O_3 would react with some kinds of reducing gas, such as CO、H_2 and CH_4, so the degree of promotion varied.
Zhungeer bituminous coal was selected as experimental materials in order to study the effect of Fe_2O_3 on pyrolysis characteristic of coal. The pyrolysis experiments of the raw coal loaded mass fraction of 0%, 5%, 10%, 20% of Fe_2O_3 were carried out in a small fluidized bed reactor, within the temperature range from 500 ℃ to 800 ℃.The results showed that, at the temperature range from 500 ℃ to 800 ℃,Fe_2O_3 could obviously reduce tar yield, but increase water yield. The effects of Fe_2O_3 on char and gas were relative to temperature. At the temperature between 500℃ and 600 ℃, Fe_2O_3 would catalyze the aromatization and polycondensation of the colloid and inhibit the cracking reaction of the colloid, thus increasing the char yield and reduce the volatiles(including gas and tar) yield. At the temperature between 700℃ and 800℃, the semi coke reacts with Fe_2O_3, therefore increasing CO and CO_2 yield. In addition, Fe_2O_3 would significantly change the pyrolysis gas components. When the temperature was low, Fe_2O_3 would promote the recombination of oxyradical, so the formation of CO and CO_2 was suppressed. And with temperature increasing, Fe_2O_3 would react with some kinds of reducing gas, such as CO、H_2 and CH_4, so the degree of promotion varied.
引文
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[13] SOLOMONPETER R, MICHAEL S, GRISH V D, et al. Cross-linking reactions during coal conversion[J]. Energy & Fuels,1990( 4) :42-54.
[14] 崔银萍,秦玲丽,杜娟,等.煤热解产物的组成及其影响因素分析[J].煤化工,2007(2):10-15.
[15] 杨景标,蔡宁生,张彦文.金属催化剂对褐煤热解气体产物析出影响的实验研究[J].工程热物理学报,2009(1):161-164.
[2] 陈延信,甘艳萍,常娜.Fe2O3对榆林煤热解动力学参数的影响[J].西安建筑科技大学学报(自然科学版),2012,44(5):736-755.
[3] ?ZTA?A N, YüRüM Y. Effect of catalysts on the pyrolysis of Turkish Zonguldak bituminous coal[J]. Energy & Fuels, 2000,14(4):820-827.
[4] 杨玉坤,王勤辉,方梦祥,等.淮南烟煤煤灰对煤热解的影响[J].燃烧科学与技术,2017,23(3):217-224.
[5] 黄振,何方,赵坤,等.赤铁矿用于生物质化学链气化氧载体的反应性能[J].农业工程学报,2011,27(增刊1):105-111.
[6] 何选明,方嘉淇,潘叶.Fe2O3/CaO对低阶煤低温催化干馏的影响[J].化工进展,2014(2):363-367.
[7] WANG P F, JIN L J, LIU J H, et al.Analysis of coal tar derived from pyrolysis at different atmospheres[J].Fuel,2013(104):14-21.
[8] STANISLAW P. The reactions of formation of selected gas products during coal pyrolysis[J].Fuel,2004,83:1191-1196.
[9] 王美君,杨会民,何秀风,等.铁基矿物质对西部煤热解特性的影响[J].中国矿业大学学报,2010,39(3):426-430.
[10] 朱廷钰,王洋.氧化铁与碳酸钾对煤温和气化的影响[J].化学反应工程与工艺,2000(2):203-208.
[11] 熊园斌.钙基矿物质影响煤热解特性的实验研究[D].杭州:浙江大学,2016.
[12] 贾晋炜,刘璐,杨凤生,等.生活垃圾催化热解液体产物特性[J].环境工程学报,2015(1):348-354.
[13] SOLOMONPETER R, MICHAEL S, GRISH V D, et al. Cross-linking reactions during coal conversion[J]. Energy & Fuels,1990( 4) :42-54.
[14] 崔银萍,秦玲丽,杜娟,等.煤热解产物的组成及其影响因素分析[J].煤化工,2007(2):10-15.
[15] 杨景标,蔡宁生,张彦文.金属催化剂对褐煤热解气体产物析出影响的实验研究[J].工程热物理学报,2009(1):161-164.