准东煤灰熔融温度表征结渣特性的试验研究

Research on Zhundong coal's ash melting temperature characterizing its slagging characteristics

针对准东煤灰熔融温度与实际结渣特性出现严重不符的问题,利用微波消解法对准东原煤和按GB/T 212—2008制得的灰(称为国标灰)进行分析,得到其金属元素含量。试验结果表明:在国标法制灰过程中,煤中的主要金属元素均有不同程度的逃逸,用金属氧化物逃逸率表征金属元素的逃逸特性,除了熔点比较低的碱金属氧化物逃逸率较高,熔点比较高的Al2O3和CaO的逃逸率也高达87.51%和58.77%,由此导致国标灰灰熔融温度升高,与煤实际的结渣特性不符。灰化温度从815℃降低到500℃后制得灰的软化温度ST为1 230℃,比国标法制得灰的软化温度1 330℃低100℃。与灰熔融温度相比,灰成分指标更能表征准东煤的结渣特性。

Abstract ： The ash mehing temperature of Zhundong coal greatly contradicts with its slagging characteristics. This paper investigates the reasons behind the poor correlation by resolving the raw coal and its ash prepared under the GB/T 212--2008 standard with microwave digestion technology （the ash obtained through this method is called standard ash in this paper）. The test results lead to and confirm the following conclusions：all the main metallic elements in the coal escape to various degrees in the process of burning coal to ash under the GB/T 212--2008 standard. Metal oxide escape rate can explain the metal elements escape characteristics, besides the escape of a great quantity of alkali metal oxide of low melting point,87.51% of A1203 and 58.77% of CaO, both with high melting points, escape during the prescribed process. The escape of metallic elements enormously influences the ash melting point, resulting in a 1 00℃ difference between the softening temperature of 1 230 ℃ of the ash made under 500℃ and that of 1 330℃ of the ash made by the international standard method. The practical slag characteristics of Zhundong coal can be more exactly described with ash composition index than with ash melting temperature. Key words： Zhundong coal ; ash melting temperature ; slagging characteristics ; ash composition