互花米草与褐煤共热解特性试验  

Experiment on co-pyrolysis characteristics of Spartina alterniflora and lignite

作　　者：李继红[1] 杨世关[1] 李晓彤[1] 

机构地区：[1]生物质发电成套设备国家工程实验室华北电力大学可再生能源学院,北京102206

出　　处：《农业工程学报》2014年第14期251-257,共7页Transactions of the Chinese Society of Agricultural Engineering

基　　金：国家自然科学基金项目(51346001);中央高校基本科研业务费专项资金(12MS45)

摘　　要：互花米草是一种高 Na、K 含量的盐生植物，直接燃烧存在结渣与沉积腐蚀问题，而与煤炭共热解可以有效发挥其高碱金属含量的特点。该文采用热重-傅立叶红外联用分析法（thermogravimetric analysis coupled with Fourier transform infrared spectroscopy，TG-FTIR）研究了互花米草与褐煤在质量比（S∶L）分别为1∶4、2∶3、3∶2和4∶1条件下的共热解特性。试验所用互花米草的Na、K质量分数分别为16064.3和6175.7 mg/kg，挥发分质量分数为75.40%，褐煤的挥发分质量分数为33.92%。TG分析表明，4种混合原料共热解均产生了协同效应，且主要表现为385～510℃温度区间内互花米草对褐煤热解的促进作用，在该温度区间内共热解反应活化能随互花米草比例的增加呈下降趋势，由褐煤单独热解时的53.62 kJ/mol最低降到S∶L为4∶1时的13.34 kJ/mol，同时共热解比褐煤单独热解反应速率常数升高幅度达到1～2个数量级。热解气体的FTIR分析表明，共热解可以提高热解气体的质量，与单独热解相比共热解可以促进CH4和CO气体的产生。从提高热解气体质量角度分析，4种混合样品中S∶L为3∶2和4∶1的协同效应更为明显。研究表明互花米草可以用作煤炭热解的可弃催化剂，拓宽了互花米草的能源化利用途径。Smooth cordgrass （Spartina alterniflora）, a saltmarsh plant, has spread in intertidal flats of many regions of China since it was introduced from the USA in 1979. The application of S. alternilfora in energy has gained more attention due to its high production. However, the direct combustion of S. alternilfora was hindered due to its high potassium （K） and sodium （Na） contents. Co-pyrolysis of biomass and coal, a subject of much study in an effort to reduce greenhouse gases emission, was reported to be able to produce a synergetic effect mainly due to the catalytic function of alkali metals in biomass. S. alterniflora, rich in Na and K which are 22 683 mg/kg and 8 063 mg/kg, respectively, has great bioenergy potential as a co-pyrolysis material of coal. In order to to verify the interaction of S. alterniflora and lignite during pyrolysis, experiments were carried out with pure S. alterniflora, pure lignite, and their blends with mass ratio （S. alterniflora to lignite, S：L） of 1：4, 2：3, 3：2, and 4：1 by thermogravimetry coupled with a Fourier transform infrared spectroscopy （TG-FTIR）. S. alternilfora used in the experiments was collected from Dafeng County of Jiangsu Province, China in October 2012. Lignite was from Shanxi Province, China. Na, K, volatile, H/C, O/C, and heating value of S. alterniflora were 16 064.3 mg/kg, 6 175.7 mg/kg, 75.40%, 0.12, 0.80, and 19.08 MJ/kg, respectively. Volatile content, H/C, O/C, and heating value of lignite were 33.92%, 0.07, 0.23, and 20.47 MJ/kg, respectively. TG tests were done under an N2 flow rate of 25 mL/min and at a heating rate of 10℃/min from 30℃ to 900℃. Infrared scanning resolution was set to 4cm-1, and scanning scope varied from 4 000 cm-1 to 500 cm-1. According to TG and DTG analysis, the process of co-pyrolysis can be divided into two stages at 385℃. The pyrolysis of S. alterniflora took place mainly in the first stage of 250℃ to 385℃. The pyrolysis of lignite and fixed carbon in S. alterniflora occurred in the second stag

关 键 词：生物质 热解 褐煤 互花米草 TG-FTIR 

分 类 号：TK6[动力工程及工程热物理—生物能] TK121