Sorption enhanced chemical looping gasification of biomass for H2 and transportation fuel production

Abstract

Sorption-enhanced chemical looping gasification (SECLG) of biomass is a promising process for H2 and transportation fuel (TF) production at reduced CO2 emissions and energy penalties. This work demonstrates a comprehensive Lagrange Gibbs Energy Minimization Aspen Plus model for the SECLG of waste bagasse to produce H2 and TF. The model compares the efficiency of high-performance Nickel Oxide (NiO) and Ferric oxide (Fe2O3) oxygen carriers. The influence of parameters including the fuel reactor (FR) temperature, pressure, equivalence ratio, and solid recirculation are examined. Transitory-state pathways of the solid carriers e.g., oxygen carrier and sorbent., during various redox loops, are evaluated. It was found that SECLG can produce syngas with a molar H2 concentration equal to or greater than 68 % at the lowest FR temperature and pressure of 600 °C and 5 bar. CO2 in the syngas is significantly limited to substantially less than 10 % of the producer gas. The overall tar yield in the syngas is attainable at low yields within 2 × 10−5 g/kg dry bagasse. The TF yield potential is promising owing to a tunable H2/CO ratio obtained post a reverse water gas shift phase. Regarding oxygen carrier performance, NiO is more efficient in delivering high-purity H2 syngas with increased CO2 sequestration while Fe2O3 gains superiority in delivering a producer gas blend with elevated combustibility potentials and a higher TF yield.