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Hydrogen-rich gas production by continuous pyrolysis and in-line catalytic reforming of pine wood waste and HDPE mixtures

Arregi, Aitor, Amutio, Maider, Lopez, Gartzen, Artetxe, Maite, Alvarez, Jon, Bilbao, Javier, Olazar, Martin
Energy conversion and management 2017 v.136 pp. 192-201
wastes, Pinus, hydrogen production, sawdust, space and time, catalysts, raw materials, polyethylene, hydrogen, pyrolysis, temperature, biomass, fluidized beds, gasification
The continuous pyrolysis-reforming of pine sawdust and high density polyethylene mixtures (25, 50 and 75wt% HDPE) has been performed in a two-stage reaction system provided with a conical spouted bed reactor (CSBR) and a fluidized bed reactor. The influence HDPE co-feeding has on the conversion, yields and composition of the reforming outlet stream and catalyst deactivation has been studied at a reforming temperature of 700°C, with a space time of 16.7gcatmingfeeding−1 and a steam/(biomass+HDPE) mass ratio of 4, and a comparison has been made between these results and those recorded by feeding pine sawdust and HDPE separately. Co-feeding plastics enhances the hydrogen production, which increases from 10.9g of H2 per 100g of feed (only pine sawdust in the feed) to 37.3g of H2 per 100g of feed (only HDPE in the feed). Catalyst deactivation by coke is attenuated when HDPE is co-fed due to the lower content of oxygenated compounds in the reaction environment. The higher yield of hydrogen achieved with this two-step (pyrolysis-reforming) strategy, its ability to jointly valorise biomass and plastic mixtures and the lower temperatures required compared to gasification make this promising process for producing H2 from renewable raw materials and wastes.