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通过改变流化床中反应性气体(水蒸气和氧气)的组成、不同粒径生物质的质量分布及流化床上部反应温度研究它们对粗气中焦油含量的影响及焦油的生成机理。实验结果表明:焦油含量随水蒸气与氧气物质的量比(以下用SOR表示)的减小、原料中小粒径生物质质量的增多及流化床上部温度的升高而降低。在较好的实验条件下,获得氢气产率为66.42g/kg biomass,H2、CO体积分数和为54.82%,焦油含量小于2g/Nm3dry gas,利于下一步催化裂解反应。焦油的生成与SOR关系密切,SOR较高时,焦油主要形成于生物质的裂解,组分复杂,并且以含氧化合物为主;随着SOR的降低,气化程度加深,带支链的苯环结构减少、少支链的苯环结构增多;当SOR降低到一定程度后,多环芳烃明显增多。
The influences of the composition of reactive gas (water vapor and oxygen), the mass distribution of biomass with different particle sizes and the upper fluidized bed temperature on the tar content in crude gas and the formation mechanism of tar were studied. The experimental results show that the tar content decreases with the decrease of the mass ratio of water vapor to oxygen (hereinafter SOR), the increase of mass of small-sized biomass in the feedstock, and the increase of the temperature in the upper part of the fluidized bed. Under the better experimental conditions, the yield of hydrogen was 66.42g / kg biomass, the volume fraction of H2 and CO was 54.82%, and the tar content was less than 2g / Nm3dry gas, which was conducive to the next catalytic cracking reaction. The formation of tar is closely related to the SOR. When the SOR is high, tar is mainly formed in the pyrolysis of biomass with complex components and mainly oxygenates. With the decrease of SOR, the degree of gasification is deepened, and the branching benzene The ring structure is reduced, and the benzene ring structure with fewer branches is increased. Polycyclic aromatic hydrocarbons (PAHs) increase obviously when the SOR decreases to a certain extent.