生物质废弃物在回转窑内热解研究——Ⅱ.热解终温对产物性质的影响

PYROLYSIS OF THE BIOMASS WASTE IN A ROTARY KILN Ⅱ:IMPACTS OF FINAL PYROLYSIS TEMPERATURE ON PRODUCTS PROPERTIES

考察了不同热解终温下木块和稻壳在回转窑内热解产物——燃气、焦油和炭的成分和性质的变化。在试验温度范围内 ,热解气体热值约 1 0 .0— 1 5.9MJ/ Nm3,密度 1 .2 1— 1 .52 Nm3/ kg,且随热解终温变化呈规律性变化。木块炭的热值为 2 9.0— 33.9MJ/ kg,稻壳炭则为 1 7.6— 2 0 .8MJ/kg,热解终温的提高使炭中挥发份的降低、灰分增多 ,从而导致热值的降低 ;炭的 C含量高于原始物料的 C含量 ,而 H、O则相反 ;元素残留率的计算表明 ,热解过程中 H和 O元素的脱除易于 C元素。热解终温对焦油中饱和烃、芳香烃成分含量的影响不大 ,饱和链烃成分主要集中为 C1 4 — C34正构烷烃和含末端双链烯烃的碳分子链 ;芳香烃主要为蒽 (菲 )、芘。

Wood chips and rice husks were pyrolyzed in a technical-scale rotary kiln.The compositions and properties of the derived gas,pyrolytic tar and solid char were determined in relation to final pyrolysis temperature(FPT)between 550 and 850℃.The gases were identified as H 2、CO、CH 4、CO 2、C 2H 4和C 2H 6,of which the volumetric contents of CO and CO 2 are more than 64%.The heat value of gas is about 10 0—15.9MJ/Nm 3 and gas density is from 1.21 to 1.52Nm 3/kg,and they change regularly with various FPT.The heat values of wood and rice husk char are 29.0—33.9MJ/kg and 17.6—20.8MJ/kg,respectively.They reduce with increasing FPT,in line with the deletion of volatile content.More element component decomposes as volatile and its quantity increases with increasing FPT.To reactivity ability of char,there seems no apparent correlation with FPT and its effects are less than that of gasification reaction temperature.The impact of FPT on the aliphatic and aromatic compositions in tar is a minor factor.The aliphatics consist mainly of n alkane,uniolifine and diolifine with double bond at end,while aromatics consist of anthracene,pyrene,fluoranthene and their alkylated hydrocarbons.