Upgradation of agricultural straw pyrolysis through co-processing with PE waste and by-product detoxification

Abstract

Co-pyrolysis of biomass and waste PE is not only an effective way to mitigate waste PE pollution, but it is also an economical method of obtaining bio-crude with high quality. However, the incomplete conversion and toxicity of by-products (char and aqueous phase) are restricting its industrialization, which is not noticed. Therefore, this study aimed at a new integrated process that is composed of co-pyrolysis, steam reforming of by-products, and heat recovery sections. Compared with traditional biomass pyrolysis, the liquid products of co-pyrolysis were heterogeneous, which is suitable for products separation. The new system reduced the energy consumption in product separation by 2389 MJ and 437.26 kWh per ton of raw materials. The O content of bio-crude was decreased from 37.97 % to 4.82 %. Compared with existing hydrogen production processes, the yield of H2 in this study was 69.4 kg/ton, and production efficiency was 71 %. For environmental assessment, biomass collection and product treatment were found as the main environmental influence factors, and the main influencing factors included pesticides, fertilizers, electricity, diesel, and exhaust gas. During seven cases, the co-pyrolysis has significantly reflected the decreasing impact of exhaust gas and electricity consumption on GWP (decreasing about 40 %-60 %). Besides, the distributed co-pyrolysis model significantly reduced the diesel consumption during biomass transportation and reduced the impact on ODP by about 60 %.