Fluidized-bed gasification combined continuous sorption-enhanced steam reforming system to continuous hydrogen production from waste plastic

摘要

This paper proposes a novel system for continuous hydrogen production from waste plastic (WP) by fluidized-bed gasification (FBG) combined sorption-enhanced steam reforming process (SERP). The system was operated in successive processes of several sections: (a) gasifying a WP into a raw gas comprising CO, H-2, CH4, total hydrocarbons (THC), and small amount of HCl contaminant, etc.; (b) passing the raw gas to hydrogen production through two moving-bed reactors by continuous SERP process over Ni-based catalyst mixed CaO sorbent for in-situ CO2 capture and HCl removal; (c) simultaneously regenerating CaCO3 formed and catalyst with carbons deposited in other moving-bed reactor at the regeneration condition selected; and (d) carrying the particles of catalyst and sorbent to continuous steam reforming and their regeneration between two moving bed reactors by riser. Gradually expanding chamber design of FBG reactor suitable for different particles flow to prolong the residence times of gas and solid phases makes high carbon conversion and the maximum value is up to 83.6% at 880 degrees C during FBG stage. The combination of FBG and SERP has produced a stream of high-purity hydrogen at some certain conditions, and about 88.4 vol % of hydrogen (H2O- and N-2-free basis) was obtained at 818 degrees C of FBG temperature with 706-583 degrees C of SERP temperature. Reduced Ni-based catalyst efficiently converted raw gas from FBG and steam to H-2, and CaO sorbent in the moving-bed reactor are capable of reducing the HCl and CO2 to low levels at all the temperatures tested. Copyright (C) 2016, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.