秸秆燃烧中温度对钾转化与释放的影响

THE EFFECT OF TEMPERATURE ON TRANSFORMATION AND RELEASE OF POTASSIUM DURING STRAW COMBUSTION

通过对稻秆原料进行常规特性分析和EDX元素含量分析,发现钾在稻秆无机元素中占有重要地位。参考原料化学分馏法和土壤中钾的分类与测试方法,给出了对生物质原料及其燃烧产物中钾的定性与定量简易方法。通过程序控温型固定床对稻秆先进行缓慢氧化,然后以100℃为间隔从400～900℃进行成灰,并分别测试其成灰率、有效钾和全钾的份额。结合稻秆原料及其灰中钾的份额分析,进行了稻秆灰中有效钾转化与释放的计算,发现有效钾在700～800℃之间有快速的释放和形态转变。稻秆灰的XRD分析结果表明秸秆灰中钾主要以KCl、K_2SO_4形式存在,得到了钾以盐的形式进行转化与释放的机理。该文中燃烧温度对钾转化与释放的影响规律对设计秸秆电厂时的炉型选择和燃烧参数确定有一定参考价值。

The characterization and EDX analysis of raw rice straw were carried out, and it was found that potassium is of importance in rice straw. The simplified analysis method was given to determine the potassium in raw straw and ash, referring to the chemical fractionation and the analysis method of potassium in soil. Different forms and contents of potassium in rice straw were measured. The rice straw was eombusted very slowly first on a fixed bed with the program temperature controller, and then was heated from 400℃ to 900℃ with an increase of 100℃. The ash fraction under different temperature was determined, as well as the available potassium and total potassium in the straw ash. It was found there was a rapid transformation and release between 700-800℃. At last, the XRD analysis of the straw ashes proved that the potassium exists mainly as KC1 and K2 SO4, the mechanism of the transformation and release of potassium as salt was achieved. The conclusion can give some reference to the boiler selection and determination of the operation parameter when a biomass power plant was designed.