灰化方法对高碱燃料成灰特性影响的实验研究

Experimental Study on the effects of Ashing Method on the Ash Characteristics of High-alkali Fuel

为探究高碱燃料在不同燃烧阶段下灰组分的形成及演变规律,本文针对小麦秸秆和紫金烟煤通过不同灰化方法制取的灰样进行了灰组分分析。等离子灰化法由于灰化温度较低(150~200℃),可以较好地保存燃料中矿物质的原始状态,而借助不同温度(575℃、815℃和1000℃)的传统制灰法可以研究灰组分的形成及演变规律。实验结果表明,小麦秸秆灰中的钾含量和紫金烟煤灰中的钠含量大致随着灰化温度的升高而减少。小麦秸秆的等离子灰中含有KClO_(4),KClO_(4)的分解是该灰样失重的原因之一。高温下紫金烟煤中的含钠矿物质会转化为霞石等,含铁矿物质也会发生一系列分解和氧化反应。小麦秸秆和紫金烟煤中的二价铁随着灰化温度的升高有被氧化为三价铁的趋势。

In order to investigate the formation and transformation of ash species at the different stages of high-alkali fuel conversion,the ashes of wheat straw and Zijin coal produced by different ashing methods were studied in this paper.The initial state of mineral in the raw fuel could be kept well due to the low temperature(150~200℃)of the plasma ashing method.The traditional ashing method with several temperatures(575℃,815℃,and 1000℃)was employed to study the formation and transformation of ash species.The results show that the potassium content in wheat straw ash and the sodium content in Zijing coal ash decrease roughly with the increasing ashing temperature.The plasma ash sample of wheat straw contains KClO_(4),the decomposition of which partly causes the weight loss of this sample.The Na-bearing minerals in Zijin coal transform into NaAlSiO_(4)and other minerals at high temperature,and the Fe-bearing minerals also go through a variety of reactions like decomposition and oxidation.The ferrous iron in wheat straw and Zijin coal tends to be oxidized as ferric iron when the ashing temperature gets higher.