Characteristics of high temperature gasification of corn stalk to produce high H₂ content syngas

Hydrogen production from biomass gasification at high temperature is a technology to produce hydrogen from renewable biomass resources. In order to explore the characteristics of hydrogen production from biomass gasification at high temperature, the effects of different gasification equivalent ratio (the ratio of actual oxygen mass to fully reacted oxygen mass), water vapor/mass ratio and gasification temperature on the gasification characteristics of corn stalk under oxygen/water vapor atmosphere are studied on a four-temperature drop-tube furnace test bench. The results show that when the equivalent ratio of gasification varies from 0.15 to 0.23, the increase of oxygen content can promote the transformation of carbon structure and hydrogen-containing functional groups in raw materials, and has an effect on the H₂ yield. When the gasification equivalent ratio continues to rise, the oxidation reaction of H₂ increases and the yield of H₂ decreases. The influence of water vapor on biomass gasification is mainly reflected in the regulation of gas phase products. When the water vapor/material mass ratio changes from 0 to 1.5, H₂ yield increases under the action of water-gas reaction. At the same time, the addition of water vapor will cause the reaction residence time to decrease, resulting in the reduction of carbon conversion rate and the decrease of CO yield. When the gasification temperature changes from 900 ℃ to 1 300 ℃, the H₂ concentration keeps rising. With the increase of temperature, the proportion of stable graphite structure decreases and the proportion of defective carbon frame increases, which is conducive to gas-solid reaction. The H₂ yield, H₂/CO ratio, export gas calorific value and yield all increase with the increase of temperature. At 1 300 ℃, the H₂ yield is 0.57 m³/kg and the H₂/CO ratio is 2.76. In the process of hydrogen production from biomass gasification at high temperature, the influence of reaction temperature is dominant, and the increase of reaction temperature will significantly increase the H₂ yield.