摘要
热解焦油作为秸秆热解炭气联产过程中的副产物,直接排放会造成严重的环境污染,通过雾化燃烧的方式能实现清洁利用。为探究热解焦油雾化规律,优化雾化工艺参数,该研究基于双流体空气雾化技术和散射谱粒度分析技术,设计了热解焦油雾化试验系统,并开展了单因素试验和正交试验,对比研究热解焦油温度、气体温度、气体压力对热解焦油稳态自由喷雾粒度及粒度分布的影响。结果表明,随着热解焦油温度、气体温度和气体压力的增加,热解焦油的索特平均直径不断减小并且均匀性更好。各因素对雾化效果的影响强弱顺序分别为热解焦油温度、气体压力、气体温度,最优雾化参数为热解焦油温度100℃,气体温度120℃,气体压力0.5 MPa,在此条件下热解焦油雾化液滴平均粒径为81μm,粒径200μm以下颗粒占比85%以上,雾化均匀性较好,该结果为热解油后续充分燃烧提供数据支持。
More than 800 million tons of residual straw produced in China each year,about half of which have not been reused effectively.Alternatively,a biochar-gas-tar polygeneration can transform agriculture residues,such as straw into pyrolysis gas,biochar,pyrolysis tar,and other products,indicating the full use of renewable resources to reduce environmental pollution.However,pyrolysis tar is a sort of inevitable by-product in the process of biochar-gas-tar polygeneration.The treatment of pyrolysis tar has become a prominent problem restricting the development of technology.The mass concentration of volatile phenol in pyrolysis tar is 156~312 mg/L,rich in aldehyde,benzene,phenol,hydrocarbon,ammonia,and heavy metals.At present,there are four main methods to treat the pyrolysis tar:high temperature cracking,catalyst cracking,plasma,and combustion.The former three methods can only reduce the emission of pyrolysis tar,but cannot eliminate or completely realize the use of tar.Moreover,there are still some problems,such as high requirements for equipment material,and high temperature bearing capacity,high cost,low efficiency,high energy consumption or catalyst deactivation.Since the energy density of pyrolysis tar is relatively high,the clean energy utilization of pyrolysis tar can be realized by burning pyrolysis tar as liquid fuel.However,the physical and chemical properties of pyrolysis tar are quite different from those of common fuel tar,such as high moisture content,high viscosity,and poor effect of atomization combustion.Therefore,it is necessary to study the atomization characteristics of pyrolysis tar under different conditions,and thereby to reveal the atomization law of pyrolysis tar,further to realize clean and efficient combustion of pyrolysis tar.In this study,an atomization test of pyrolysis tar was designed using two technologies of fluid atomization and scattering particle size analysis,in order to ensure the stable combustion and atomization of pyrolysis tar.The single factor and orthogonal experiments were carried out to compare the effects of tar temperature,gas temperature,and gas pressure on the particle size and its distribution in the steady state free spray of tar.The results showed that the optimal effect of tar atomization was achieved,when the temperature of tar exceeded 60℃,the temperature of gas exceeded 80℃,and the pressure exceeded 0.3 MPa.With the increase of tar temperature,air temperature and air pressure,the SMD of tar droplets decreased.The influence of each factor on atomization effect was ranked in a descend order:tar temperature,gas pressure,and gas temperature.The small particle rate of pyrolysis tar accounted for more than 85%,where the optimal atomization pyrolysis tar temperature was 100℃,gas temperature was 120℃,and the gas pressure was 0.5 MPa,indicating a good atomization effect on pyrolysis tar.The proposed system can provide a potential data support for clean combustion and comprehensive utilization of pyrolysis tar.Since this experiment mainly studied the pyrolytic tar atomization,the next step can be set to carry out the investigation on pyrolytic oil atomization combustion combined with atomization parameters.
作者
郝晓文
贾吉秀
姚宗路
赵立欣
霍丽丽
康康
张喜瑞
Hao Xiaowen;Jia Jixiu;Yao Zonglu;Zhao Lixin;Huo Lili;Kang Kang;Zhang Xirui(Institute of Environment and Sustainable Development in Agriculture,Chinese Academy of Agricultural Sciences,Beijing 100081,China;Mechanical and Electrical Engineering College,Hainan University,Haikou 570228,China;Institute for Chemical and Fuel Conversion of Alternative Resources(ICFAR),University of Western Ontario,London,Ontario N0M 2A0,Canada)
出处
《农业工程学报》
EI
CAS
CSCD
北大核心
2020年第23期250-257,共8页
Transactions of the Chinese Society of Agricultural Engineering
基金
中国农业科学院科技创新工程
现代农业产业技术体系专项资金资助(CARS-02-31)。
关键词
试验
喷雾
热解
炭气联产
焦油
experiment
spray
pyrolysis
co-production of carbon and gas
tar
