为了解秸秆类生物质烘焙过程中钾的迁移转化及后续燃烧过程中的释放规律，采用管式炉对玉米秸秆进行烘焙预处理，利用分级萃取结合ICP-AES（电感耦合原子发射光谱仪）测量了不同温度烘焙后样品钾的释放率及不同类型钾的转化。采用多点LIBS（Multi-point LIBS）技术测量了烘焙后玉米秸秆颗粒燃烧过程中钾的释放情况。结果表明，生物质烘焙过程中，烘焙温度越高，有机官能团活性越强，水溶型钾转化成有机钾越多。烘焙样品在后续燃烧过程中，不同类型钾在脱挥发分阶段和焦燃烧阶段的释放明显不同。低温烘焙的玉米秸秆燃烧时，在脱挥发分阶段释放峰值高，释放总量多，这与钾富集、样品出现孔隙等有关，而在焦燃烧阶段释放较少。高温烘焙的玉米秸秆燃烧时，在脱挥发分阶段释放浓度低，释放率低；在焦燃烧阶段释放较多，这与挥发分少、灰分高等原因有关。烘焙前后玉米秸秆水溶型钾占比均最大，燃烧时水溶型钾的释放率与总钾释放率接近，表明水溶型钾的释放对总钾释放率起主导作用。

In order to research the transformation of potassium in the torrefaction and the release law of subsequent combustion process of straw biomass,corn straw was pretreated in a tubular furnace,and the release rate of potassium and the conversion of different classes of potassium were measured by fractional extraction combined with ICP-AES after torrefaction at different temperature. A multi-point LIBS system was used to measure the release of potassium during the burning of corn straws in real time. The results show that the higher torrefied temperature is,the stronger the activity of organic functional groups is,and the more H2O-soluble potassium is converted into organic potassium. The release of different classes potassium of torrefied samples in the volatilization and the char stage are significantly different in the subsequent combustion. During the combustion of corn straw torrefied at low temperature,the release peak of devolatilization is high and the total amount of devolatilization is large,less is released during char combustion,which is related to potassium enrichment and porosity of samples. The release concentration and release rate of high temperature torrefied corn straw in devolatilization stage are low. In the char combustion stage,the release of more is related to less volatile matter and higher ash. The proportion of H2O-soluble K in corn straw before and after baking is the largest,and the release rate of H2O-soluble K is close to the total K release rate during burning,indicating that the release of H2O-soluble K plays a leading role in the total K release rate.

0 引言

1 试验

   1.1 样品预处理及制备

   1.2 试验方案

2 结果与讨论

   2.1 玉米秸秆烘焙过程中钾的迁移释放特性

   2.2 烘焙玉米秸秆燃烧时钾动态释放特性

   2.3 不同燃烧阶段及不同类型钾的释放总量

3 结论