生物质热风炉在粮食烘干中的改进与应用

Improvement and Application of Biomass Hot Blast Stove in Grain Drying

目前生物质热风炉基本上都是基于原有燃煤炉的简单改造,沿用传统煤的绝热燃烧的方法,燃烧形式比较粗放。存在燃烧不充分、燃烧效率低、尾部烟气NOx浓度高、烟尘堵塞换热面等问题,为了使烟气温度能够降到满足后续烘干要求,通常采用向炉内通入冷空气,增加了烟气中的氧含量,致使环境指标不达标,且经济效益差。为了解决目前存在的问题,本生物质热风炉基于生物质燃料的燃烧特性,综合经济、环保两方面考虑,通过以下方法进行了改造:a.加宽炉排;b.增加炉膛内部空间;c.密封锅炉系统;d.合理设置烟气再循环;e.合理配置二次风位置及风量;f.炉膛底部布置二氧化碳脉冲喷气管。通过上述改造,热风炉在运行过程中具有良好的经济指标与环境指标。同时本次改造后提供了运行过程中的最优参数。

The conversion of coal fired furnace into biomass furnace can not address the issues arise from traditional adiabatic combustion-incomplete combustion,low efficient in burning,high concentration of NOx,clogging of heat exchange surface,etc.Moreover,cold air is injected into furnace for lowering the temperature for following up drying process.The injection inevitably increase the oxygen concentration of flue gas and consequently lead to higher emission and raise the energy production cost.The following measures are taken to re-construct the biomass furnace based on the characteristics of biomass fuel,economical and environmental considerations:a.widen the grate;b.enlarge the internal space of combustion chamber;c.seal the boiler system;d.optimization of flue gas re-circulation;e.optimization of supply of secondary air;f.equipment of gas ejector at the bottom of combustion chamber.Those measures improve the economical and environmental indicators of furnace.