垃圾热解-挥发分重整过程中基于产物导向的催化剂选择

Product oriented catalyst choice during MSW pyrolysis and volatile reforming process

为进一步提升垃圾热解产物品质,提高目标产物的产量,在垃圾热解反应器下游设置自源半焦重整挥发分的反应器,并在自源半焦中混入白云石(D)和活性污泥炭(ASSC)以提升催化效果,获得更多的气体资源以及高品质的油。结果表明,550℃下垃圾热解产生的挥发分经同温自源半焦重整,气体产率可提高44.29%,热解液产率降低了41.33%;但热解油中的脂肪烃含量下降,单环芳烃含量增加。添加煅烧白云石后,热解油转化率提高,热解油中的脂肪烃含量增加。添加ASSC后,H2、CO产率显著提高;热解液产率进一步降低。特别是与自源半焦按照等质量与ASSC混合时,热解液产率最低,自30.44%降至11.25%,同时其含水率自57.23%降至35.64%。总体上,垃圾热解自源半焦具有促进热解油中单环芳烃生成和脂肪分解的作用;而白云石和ASSC都能促使热解油中脂肪烃的浓度提升,尤其是ASSC。白云石对应着气体产物中更高的CH4、H2和CO的产率,而ASSC进一步促进了H2和CO的生成、H2O的消耗但同时抑制了CH4的生成。当以合成气为目标产品时,推荐加入ASSC并与自源半焦按质量比1∶1混合,其产气量达到45.5%或0.50 m^3/(kg MSW),H2+CO体积分数达到53.87%。

To further improve the quality of the waste pyrolysis products and increase the yield of the target product,a reactor from the source semi-coke reforming volatiles is disposed downstream of the waste pyrolysis reactor, anddolomite(D) and activity are mixed in the self-source semi-coke. Dolomite(D) and activated sewage sludge char(ASSC) were added into the char to improve the catalytic effect and to obtain higher gas yield and oil of betterquality. The research results showed that, when the volatiles generated from MSW pyrolysis(550℃) wereisothermally reformed by the MSW char from the same pyrolysis process the gas yield increased by 44.29% and thepyrolytic liquid yield decreased by 41.33%. In this process the aliphatics in pyrolytic liquid decreased, whilemonoaromatics increased. As dolomite was added as a catalyst modifier, the pyrolytic oil and its oxygenates. content were further reduced. When ASSC was used as catalyst modifier, it enhanced the conversion of the pyrolytic liquidinto gas. Especially for the scenario of Char∶ASSC=1∶1 by mass ratio, the pyrolytic liquid yield decreased from 30.44% to 11.25%, and its moisture content was reduced to 35.64% from 57.23%. In general, the char from MSWpyrolysis had the effect of promoting the formation of monoaromatics and decomposition of aliphatics in liquidproducts, while both dolomites and ASSC, especially the later, increased the aliphatics’ concentration in thepyrolytic liquid. The addition of dolomite promoted the yields of CH4, H2 and CO in the gas product, while theaddition of ASSC greatly facilitated the production of H2 and CO based on the higher level consumption of H2O vapor in the volatiles, but inhibited the production of CH4. When syngas is the target product, char and ASSCmixture can be recommended with the blending ratio of char∶ASSC=1∶1, for which the gas yield reaches 45.5%or 0.50 m^3/(kg MSW), and the volume percentage of the syngas(H2+CO) achieves 53.87%.