A pulsating H2O approach to improve biochar reactivity and syngas
quality: Mechanism, priority and optimum
Abstract
The reaction of biochar-CO2 (C-CO2) is the speed-control reaction in a
real-world gasifier. In this study, a new impulsive H2O(g) approach was
introduced and optimized to improve the reactivity and syngas quality
from biochar gasification using a TG analyzer and a tube furnace. An
interaction of “independent to competitive” effect was observed during
D-biochar gasified in CO2/H2O(g) under diffusion reaction regime.
Micropores suitable for C-CO2 was produced by H2O(g) within a specific
stage, which created the desired synergistic effect between C-CO2 and
C-H2O(g). The introduction of pulsating H2O(g) was employed to supply
micropores for C–CO2 and avoid the pore expansion effect of C–H2O(g)
(which is negative to C–CO2). As a consequence, an improvement on the
obtained syngas yield and a remarkable H2O(g)-saving effect were
achieved using the new approach on the premise of not significantly
reducing the corresponding carbon conversion than using the traditional
mixed CO2/H2O(g) method.