Volatiles effects on the thermal and chemical structures of H2 production in a hybrid porous media reactor using solar steam

A numerical simulation was performed to model the gasification of carbonaceous feedstocks inside a batch reactor operating on a hybrid filtration combustion mode in presence of solar steam aiming to hybridize conventional process. Results were validated against empirical data collected using sub bituminous coal, focusing in the effect of implementing a volatilization model to the simulation. Temperature and concentration of gaseous products of the combustion wave were reported as function of steam presence, filtration velocity and fuel content inside the porous bed. Solar steam was produced in a hybrid thermal/electric boiler powered by a PV-array and heat pipes, achieving up to 19% of concentrated solar input in the generation of steam. Numerical simulations showed a good qualitative agreement with experimental results. The main numerical and empirical results showed that increasing the coal presence favored a normal thermal structure, observing a maximum temperature of 1,638 K at a 70% coal mass fraction, while an increase on the steam content resulted on a shift from a normal to an inverse thermal structure recording a peak temperature of 1,618 K at a 0.95 H2O/O-2 fraction and 50% coal presence. Finally, H-2 production was observed to increase with an increment of coal fractions which was only properly simulated when including a devolatilization model. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

Numerical simulations and experimental results showed that increasing coal content favored a normal thermal structure, while increasing steam content led to a shift from normal to inverse thermal structure. The presence of steam significantly affected the temperature and concentration of gaseous products of the combustion wave.