熔盐热裂解生物质制生物油

Bio-oil production from biomass pyrolysis in molten salt

为探讨热裂解条件对熔盐中生物质热裂解制生物油的影响,在自行设计的反应器中,以摩尔比为7∶6的ZnCl2-KCl混合熔盐作为热裂解的热载体、催化剂和分散剂,考察了500℃时添加的金属盐和生物质原料的影响,并采用气相色谱-质谱仪(GC-MS)对生物油的主要组成进行了分析。结果表明:添加的金属盐显著影响热裂解产物得率,稀土金属盐显著提高生物油得率,降低生物油的含水率,添加摩尔分数为5.0%LaCl3时生物油得率为32.0%,含水率为61.5%;水稻秸秆热裂解的生物油和焦炭得率较高,稻壳热裂解的气体得率较高;金属添加盐对生物油组成有较强的选择性,LiCl和FeCl2对生物质向小分子裂解具有较强的催化作用,而CrCl3、CaCl2和LaCl3对生物油二次裂解具有抑制作用。研究结果为熔盐热裂解生物质制生物油提供了参考。

In order to investigate the effects of pyrolysis conditions on bio-oil production from biomass in molten salt,experiments of biomass pyrolysis were carried out in a self-designed reactor in which the molten salt ZnCl2-KCl（with mole ratio 7/6） was selected as heat carrier,catalyst and dispersion agent.The effects of metal salt added into ZnCl2-KCl and biomass material on biomass pyrolysis were discussed,and the main compositions of bio-oil were determined by GC-MS.Metal salt added into molten salt could affect pyrolysis production yields remarkably.Lanthanon salt could enhance bio-oil yield and decrease water content in bio-oil,when mole fraction of 5.0% LaCl3 was added,bio-oil yield could reach up to 32.0%,and water content of bio-oil could reduce to 61.5%.The bio-oil and char yields were higher when rice straw was pyrolysed,while gas yield was higher when rice husk was used.Metal salts showed great selectivity on compositions of bio-oil.LiCl and FeCl2 promoted biomass to pyrolyse into smaller molecular weight compounds.CrCl3,CaCl2 and LaCl3 could restrain second pyrolysis of bio-oil.The research provided a scientific reference for production of bio-oil from biomass pyrolysis in molten salt.