农业机械学报2017，Vol.48Issue(4)：271-275,223,6.DOI:10.6041/j.issn.1000-1298.2017.04.035
木屑热解挥发物冷凝特性研究
Condensation Characteristics of Volatile Matter from Sawdust Pyrolysis
摘要
Abstract
Pyrolysis is a relatively simple,inexpensive,and robust thermochemical technology for transforming biomass into bio-oil,biochar and syngas.While the intention of slow pyrolysis is to produce mainly charcoal,fast pyrolysis is meant to convert biomass to a maximum quantity of liquids (bio-oil).Biochar can be used with existing infrastructure as a replacement for pulverized coal,bio-oil can be used as a fuel in existing industrial boilers.The pyrolysis of sawdust contains volatile bio-oil and noncondensing gas,so the condensation characteristics are different from those of other simple mixture.Based on the test system of biomass pyrolysis volatile matter condensation characteristic parameter,the experiment of condensation characteristics of pyrolysis volatile was carried out at 450℃,550℃ and 650℃.The condensation characteristics of volatile matter produced at different pyrolysis temperatures were tested,and the heat transfer coefficient,the thermal resistance and thickness of condensation liquid film were calculated.Based on the one-dimensional heat transfer characteristics of liquid condensation,the condensate film formation process had three stages:formation,accumulation and flow of liquid film.The results showed that the first stage condensation heat transfer coefficient was decreased with the increase of temperature,biomass volatile surface heat transfer coefficient at 450℃ was the highest,which was 671.02 W/(m2 · K);with the increase of temperature,the heat transfer coefficient of the second stage was increased first and then decreased,biomass volatile surface heat transfer coefficient at 550℃ was the highest,which was 1.484 × 105 W/(m2· K).According to the experimental value and the hypothesis of condensate film,in the film formation and accumulation stage,the film thickness was gradually increased and the thermal resistance was decreased;early in the liquid film flow stage,with the decrease of the film thickness,the thermal resistance was decreased;in the steady flow stage,resistance was remained stable.The research result can provide reference for the on-line collection of bio-oil and the design of bio-oil condenser in continuous pyrolysis equipment.关键词
木屑/热解/冷凝特性/换热系数/液膜模型Key words
sawdust/pyrolysis/condensation characteristics/heat transfer coefficient/liquid film model分类
农业科技引用本文复制引用
王明峰,陈志文,蒋恩臣,任永志,韩平,孙焱..木屑热解挥发物冷凝特性研究[J].农业机械学报,2017,48(4):271-275,223,6.基金项目
科技部农业科技成果转化资金项目(20150237)和广东省科技计划项目(20160221) （20150237）
