Experimental Study on Chemical Looping Co-gasification of Alfalfa and Polyethylene with Iron Ore as the Oxygen Carrier for High H₂/CO Production

Abstract

Biomass and plastic waste gasification has been demonstrated as a promising technology for developing a long-term waste management system that reduces emissions and enhances energy recovery. Chemical looping co-gasification of alfalfa (AL) and polyethylene (PE) with Fe2O3 as oxygen carrier (OC) was studied in a fixed-bed reactor. The effects of temperature, steam/alfalfa mass ratio (S/AL), OC/alfalfa mass ratio (OC/AL), and PE/alfalfa mixing ratio (PE/AL) were investigated. The results revealed that at a gasification temperature of 950 °C, the optimum product distribution was achieved with a S/AL ratio of 1, an OC/AL ratio of 0.5, and PE/AL mixing ratios of 50 and 75%. The presence of PE in the feedstock led to higher production of synthetic gas, particularly the hydrogen yield, as the H2/CO ratio increased to more than 2 to match the demand of Fischer–Tropsch synthesis. At a mixing ratio of 50%, the lower heating value and the H2/CO ratio achieved their maximum values of 14.05 (MJ/Nm3) and 2.50, respectively. This research clarified that the combined gasification of biomass with plastic constitutes an ideal approach for high-quality synthesis gas production as well as environmental preservation and materials recycling.

A Critical Outlook on Lignocellulosic Biomass and Plastics Co-Gasification: A Mini-Review

“…In addition, the CO and H 2 in the produced gas increased by adding up to 25% LDPE. Another study by Al-Qadri et al 19 utilized alfalfa and polyethylene for steam co-gasification in a fixed-bed single-stage gasifier. When the gasification temperature hiked from 800 to 1000 °C, the CO and H 2 contents of the syngas increased by 28.92% and 26.28%, respectively.…”

“…Due to the increasing population, industrialization, and rapid urbanization, plastic waste has been increasing every year . Only 21% of plastic waste is recycled each year, and if adequate waste management is not adopted, the globe will amass 12,000 tonnes of waste plastic by 2050 . The traditional approaches to managing plastic trash are landfilling or buildup in the environment, incineration, and recycling .…”

“…18 Only 21% of plastic waste is recycled each year, and if adequate waste management is not adopted, the globe will amass 12,000 tonnes of waste plastic by 2050. 19 The traditional approaches to managing plastic trash are landfilling or buildup in the environment, incineration, and recycling. 20 Globally, over 70% of plastic waste is deposited in the natural environment or landfills.…”