State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan 430074, China.
State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan 430074, China; China-EU Institute for Clean and Renewable Energy, Huazhong University of Science and Technology, Wuhan 430074, China.
Sci Total Environ. 2022 Dec 20;853:158107. doi: 10.1016/j.scitotenv.2022.158107. Epub 2022 Aug 31.
Sludge pyrolysis and biomass gasification integrated process (SPBG) is an attractive route for the comprehensive utilization of the two materials but more tar is produced in this process compared to traditional biomass steam gasification. Nitrogen-containing compounds in the tar bring threatens to the environment and heavy components in the tar contributes to undesired coke formation. In current study, the evolution of heavy tar, especially the nitrogen-rich components, during SPBG is revealed for the first time. It was found that heavy components were mainly distributed in the mass range of 150-450 Da, where aromatics consisted of carbon, hydrogen and nitrogen atoms were the most abundant. Deamination (NH) and the combination of quinoline accompanied with the generation of the heavy components. Organics from sludge could react with biomass to form heavier oxygen-containing molecules. Meanwhile, steam from sludge promoted heavy components to crack by tar reforming reactions and consumed radicals in bio-char to inhibit the catalytic cracking of tar. Under the combination of above reactions, more heavy molecules were generated at low sludge volatile/biomass ratio and the aromatic content in the heavy tar decreased at high sludge volatile/biomass ratio.
污泥热解与生物质气化集成工艺（SPBG）是综合利用这两种材料的一种有吸引力的途径，但与传统的生物质蒸汽气化相比，该工艺会产生更多的焦油。焦油中的含氮化合物对环境构成威胁，而焦油中的重质成分则导致不希望的焦炭形成。在当前的研究中，首次揭示了 SPBG 过程中重质焦油（特别是富氮成分）的演变。结果发现，重质成分主要分布在 150-450 Da 的质量范围内，其中含有碳、氢和氮原子的芳烃最为丰富。脱氨（NH）和喹啉的结合伴随着重质成分的生成。污泥中的有机物可以与生物质反应，形成更重的含氧分子。同时，污泥中的蒸汽通过焦油重整反应促进重质分子的裂解，并消耗生物炭中的自由基，以抑制焦油的催化裂解。在上述反应的共同作用下，在低污泥挥发物/生物质比下会生成更多的重质分子，而在高污泥挥发物/生物质比下，重质焦油中的芳烃含量会降低。
