玉米秸秆高温气化制备富H2合成气特性

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

  • 摘要: 生物质气化制氢是一项利用可再生生物质资源制取氢气的技术。为探索生物质高温气化制氢特性,在高温滴管炉试验台上,研究氧气/水蒸气气氛下,不同的气化当量比(实际氧气质量和完全反应的氧气质量的比值)、水蒸气/物料质量比和气化温度对玉米秸秆气化特性的影响。结果表明:气化当量比从0.15增长到0.23时,氧气量的增加会促进原料中碳结构和含氢官能团的转化,对于H2产率有提升作用;气化当量比继续上升时,H2的氧化反应增强使得其产率下降。水蒸气对生物质气化的影响主要体现在气相产物的调节,水蒸气/物料质量比从0增长到1.5时,H2产率在水煤气变化反应作用下上升,CO产率下降,H2/CO产率比例持续上升,同时水蒸气加入后会引起反应停留时间减少,导致碳转化率降低。气化温度从900 ℃到1300 ℃变化时,H2体积分数不断上升,温度的上升强化了玉米秸秆的热解、气固反应和蒸汽重组,H2产率、H2/CO产率比例和出口气热值、冷煤气效率都随着温度的升高而上升,同时气化残炭中稳定的石墨结构比例降低,缺陷碳架的结构比例增加,表明高温有利于气固反应。1300 ℃时,H2产率为0.57 m3/kg,H2/CO产率比例为2.76。在生物质高温气化制氢过程中,反应温度的影响占据主导地位,提高反应温度会使得H2产率显著上升。

     

    Abstract: 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.

     

/

返回文章
返回