进口低灰褐煤灰分测定方法的对比分析

Comparative Analysis of Ash Content Determination Methods of Imported Low-Ash Lignite

本文建立了2种低灰褐煤灰分的测定方法:一种是减少高温灼烧时间法,另一种是增大灰皿表面积法。减少高温灼烧时间是因为进口低灰褐煤灰分低、易燃烧,将灼烧时间改为在500℃下灼烧10 min、815℃下灼烧20 min,可使煤样灼烧至质量恒重。增大灰皿表面积是为了增加煤样与空气的接触面积,可以提高单位时间内煤样与氧气的反应速率,促使煤样在特定的温度下快速灼烧至质量恒重。减少高温灼烧时间法与缓慢灰化法的F值在1.15~2.38之间;增大灰皿表面积法与缓慢灰化法的F值在1.02~3.92之间。当置信度P=95%时,F<F_(0.05,6)=4.28,因此增大灰皿表面积法或减少高温灼烧时间法与缓慢灰化法精密度不存在显著性差异。这两种方法操作简单、方便、快捷,具有可操作性强的优点,能够解决进口低灰褐煤灰分快速测定的难题,更好地满足日常检测工作需求。

In this paper,two methods for the determination of ash content in low-ash lignite are established:one is to reduce the burning time at high temperature,and the other is to increase the surface area of the ash dish.The reduction of the high-temperature burning time is due to the low ash content and flammability of imported low-ash lignite,and the burning time is changed to 10 min at 500℃ and 20 min at 815℃,which can make the coal sample burn to a constant weight.The purpose of increasing the surface area of the ash dish is to increase the contact area between the coal sample and the air,which can increase the reaction rate between the coal sample and oxygen per unit time,and promote the rapid burning of the coal sample to a constant mass at a specific temperature.The F-value of the method of reducing the high-temperature burning time and the slow-ashing method was between 1.15-2.38,and the F-value of the method of increasing the surface area of the ash dish and the slow-ashing method was between 1.02-3.92.When the confidence level is P=95%,F<F_(0.05,6)=4.28,so there is no significant difference in the precision between the method of increasing the surface area of the ash dish or reducing the high-temperature burning time method and the slow-ashing method.These two methods are simple,convenient and fast to operate,and have the advantages of strong operability,which can solve the problem of rapid determination of ash content of imported low-ash lignite and better meet the daily detection work.