稻壳低温气化特性的研究
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摘要
我国是世界上稻谷产量最高的国家，稻壳资源丰富.因技术、经济等原因，大部分稻壳被当作垃极废弃处理，不但浪费了宝贵的资摞，而且还极大地污挠了环境.若将稻壳有姓地加以利用，变废为宝，不但能够创造一定的经济效益，还可以减小环境污蜂.我国稻壳气化发电技术已经取得了一定的成功，但传统的高温气化方式，尚且不能解决稻壳气化的灰渣处理以及焦泊二次污弟等问题:
若将稻壳在低温下进行气化，通过控制碳的转化率，有望能够获得具有较高价值的稻壳炭，利用收集装置回收焦油，能够得到具有应用价值的焦泊，从而较好地解决稻壳高温气化存在的问题.为此，本文开展了稻壳低温气化试验研究.
利用热重一傅立叶红外联用方法，研究了稻壳在10'C/min.20'C旭in，30.C/min三个不同的升温速率下，热解时的失童和挥发分析出特性:并利用C铺路，~Redfem积分法进行了稻壳热解动力学研究.研究结果表明:升温速率对稻壳的热解过程影响较小，仅使得热解曲线略微偏向高温区:升温速率越低，热解越充分，挥发分析出量也越多，热解残留物也相应地减少z稻壳热解反应为一级反应:在不同的升温速率下热解时，稻壳发生的热解反应不同t在所研究的升温速率范围内，1O"C/min
时热解反应的活化能最小，20t:/min时热解反应的活化能最大.在以上研究的基础上，选择了八个不同的工况，越行了稻壳低温气化试验。利用燃气分析仪分析了燃气成分，井进行了相关参数的计算，进而讨论了气化温度和当量比对燃气特性的影响规律:分析了稻壳炭的固定碳含量，使用扫描电镜、氯气吸附仪分析了稻壳炭的孔隙结构，并使用粒度分析仪分析了稻壳炭的粒径分布:最后使用色谱一质谱联用仪(GC-MS)分析了焦泊的成份;通过对气、液、固三相产量的计算，对系统进行了质量平衡计算.试验结果表明:在5∞-7∞℃范围内，
可燃气含量、燃气热值、产气率、碳转化率和气化效率随着气化温度的升高先增大后减小，然后又增大，在6OO"C呈现最大值1当量比在0.22-0.35范围内，可燃气含量、燃气热值、碳转化率和气化效率随着当量比的增大先增大后减少，在0.3时呈现最大值，但产气率随着当量比增大一直增大.
稻壳炭的固定碳含量与气化温度、当量比都呈反相关关系，稻壳在6∞℃气化时，得到的稻壳炭具有较好的孔隙结构，在此温度下，稻壳炭的BET比表面积随当量比的增大而减小，最大值对应的当量比为0.22.样品的粒径和BET比面积变化趋势是一致的，较小的粒径对应较大的比表面积.焦泊的主要成分是带有含氧基团的茶、酶、商和酷类.八个工况的系统质量平衡计算相对误差<8%.
关键词z稻壳:流化床:低温气化t燃气:焦泊:稻壳炭
Abstract
α由tais世le命百tbig ∞untryin阴ddyyield, meanwhiIe the rice husk resource is rich. Due ω
伽:hniω181划时onomiccaω筒"m臼tof由erice h四kjs treated筒W部tewhich not only w毗precious
resource, but also pollutes the environment gr回lIy.Ifthe rice husk can be used e笛cientJy，changing waste
inωvaluables，也iscan oot only produce certain economic benefit, but also reduce env祉onmen时pollution.
Biomass回si负创ionpower gener划佣hasachievedωrtain success in Chi础，but也etraditional high
阳nperaturegasification method凶nnc此so)verice hu11出htr.四tment，se∞n也rypoll皿ionof tar and 0出er
probJems by far. If伽ricehusk would be g臼jfiedat low能mperature，by con衍。I1ingcarbon∞nversion
e伍cien町，tbe rice husk char and tar can be reclaimed by coJlecting device, it is hopefulωobtain rice husk
char and tar wi役1high v划t后，缸ldsolve the existing problems ofhigh-temperaωre gasification method welI.
Therefore, low temperature gasification of rice husk w担studiedin this p叩er.
TG-FTIR凶，terconnectionmeÛlod was u民dto拙1dy由eweight loss and volatilization precipitation
cbaract创叫CSof rice husk pyrolyzed at出reediff衍'entbeating rate: 10.C/min, 20"C/min, 30"C/mín; And
the Coats-Redfem integration m创hodwas usedω础Jdy岱lekinetics of rice husk pyrolysis. 1be results
showed伽81:heating rate has smaU influence on脂pyrolysispr饵essof rice husk, which only makes the
curv臼ofpyrolysis deviate to high tem归回归爬region;The lower the heating rate is，也，emore fully
pyrolysis佣几位lemore amount of volatilization can e础田1，and the∞πesponding pyroJysis residue is less;
ηrolysis reaction of rice husk is白宫torder reaction;而epyrolysis re削onisd幽rentwhen rice busk w部
pyrolysed at different heating rate; In由erange of heating刚esωdi时，伽ac往vationenergy of pyroJysis
reaction 1S lowest at 10 "c刷inand higbest at 20"C/1皿n.
on岱ebasis of the S'阳diesabove, eight di货运rentworki鸣conditionswere臼lec时to曲low
temp臼"atUI冒伊sificationof rice husk study. The composition of coal g部W描analyzedwi役'伊sanalysis
instrument, and related p缸ameterswereωlcul创ed，割dthen伽ee能ctlaw of gasification temperature and
equìvalent ratio on cωl回schara.cteristics were discussed;ηle fixed carbon∞ntent of rice husk char w部
analyz碍，由epore strücture of rice husk cbar W8S制a1yzedby scanning elec衍onmiα。比opy，nitrogen
adsorption, and tbe particle size distríbution w部analyzedby归rtidesize analysis in蛇ument;Finally, the
∞mposition of tar was创taJyzedby GC-MS. With the calculation ofthe yieJd of gas. liquid and solid ph蹈、
m皿sbalance of s归temw;臼calculated.ηleresults showed伽at:with伽eincrease of tem阳双urein伽e
range of 500-7∞"C， combustible gasωntent，伊sheat value, g部productionra饨，carbon conversion 18te
E
and gasific甜onefficiency incre笛edat命star叫伽endecreased, then伽eabove parameters woutd
incre路edslowly, the maximum v:刨出presentedat也e能mpera阳reofωO"C.With the increase of
叫uivalentralio in the range of 0.22-0.35，∞mbustible gas∞ntent， gas heat VaI峙:，car协nconversjon rate
and伊sificatiooefficiency increas时创甜苦tand也钮decreas础，the maximum value presented with
叫川valentratio ofO.3, but gas归。ducti佣rateincreased with the incre画eof equiva1ent ratio all创ong.白m
fix创carbon∞ntenthas inverse∞rre)甜onrel甜onw油gasifiωnontemperature and叫回val侧目邸，世m
rice husk char has g创xl萨m拮阳turewhen rice husk was gasified al仪)()"C. at this 1而lpera阳re，the BET
S归cificsurf邸earea decreased with the incre，皿eof equiva1ent ratio, and the maximum va1ue presented at
0.22. The diameter of samp)es changed uni岛nnlywith BET specific area, small diameter ωπ部，pondenced
ωbig BET 取比ificarea;也emain∞mponents of tar were naph由atene，ether, ketone and phenols
∞lotaìning oxygen speci臼81'0叩aηlCrel甜veerrors of町stemm出sbalance of eight wo汰ing∞，nditions
