神府块煤干馏过程中颗粒破碎与无机矿物质赋存规律

Particle breakage and inorganic mineral occurrence during pyrolysis of Shenfu lump coal

为研究神府煤田低阶煤在内热立式干馏炉内干馏过程中的破碎特性和无机矿物质分布规律,分析了干馏用主力低阶煤的基础煤质特性和其中所含主要无机矿物质,研究了13家使用相同干馏工艺和规模的兰炭企业的内热立式干馏炉所产兰炭的粒度分布、工业分析和无机矿物组成情况,并采用井式炉制备了不同温度热解兰炭,采用兰炭机械强度测定仪对兰炭进行机械破碎,分析了破碎后兰炭的粒度分布和不同粒度兰炭灰分产率情况。结果表明:神府煤田不同矿区原煤的基本组成、无机矿物质含量和热稳定性存在显著差异。SiO_(2)、CaO、Al_(2)O_(3)和Fe_(2)O_(3)是原煤灰分的主要成分,原煤灰分中SiO_(2)含量最高,随原煤中灰分升高,煤灰中SiO_(2)含量逐渐增高,CaO含量逐渐降低。中块兰炭和小块兰炭在干馏炉所产兰炭中占比最高,二者之和超过62%。块煤在干馏过程颗粒破碎程度主要由原煤本身属性和炉内机械作用决定,通过原煤的热稳定性可预测大致原煤在干馏炉内颗粒破碎的程度,基于原煤热稳定性T_(S+6)确定了工业生产时兰炭末质量占比预测公式。随兰炭粒度降低,兰炭灰分先降低后升高,兰炭灰分中SiO_(2)和Al_(2)O_(3)含量先升高后降低,而CaO含量先降低后升高,中块兰炭SiO_(2)和Al_(2)O_(3)含量最高,CaO含量最低,兰炭灰分产率由原煤灰分产率及兰炭在干馏炉内的反应程度决定。随干馏温度提高,受煤中挥发分析出和有机基团变化的影响,兰炭破碎程度先升高后降低再升高。

To investigate the crushing characteristics and distribution patterns of inorganic minerals in low-rank coal from the Shenfu coalfield during carbonization in a vertical retort furnace,this study analyzed the basic coal quality characteristics and main inorganic minerals.Examined the particle size distribution,proximate analysis,and inorganic mineral composition of semi-coke produced by 13 companies using internally heated vertical retorting furnaces with the same process and scale.Pyrolytic semi-coke was prepared at different temperatures using a well-type furnace,semi-coke was then crushed using a mechanical strength determination equipment,and the particle size distribution of the broken charcoal and the ash yield of semi-coke with different particle sizes were analyzed.The results indicate significant differences in the basic composition,inorganic mineral content,and thermal stability of coal from different mining areas in the Shenfu coalfield.SiO_(2),CaO,Al_(2)O_(3),and Fe_(2)O_(3)are the main components of raw coal ash,with SiO_(2)content being the highest.As the ash yield in coal increases,the SiO_(2)content in coal ash gradually increases while CaO content decreases.Medium-sized semi-coke and small-sized semi-coke collectively make up over 62%of semi-coke output from vertical retort furnace.The level of particle fragmentation in lump coal during carbonization is primarily influenced by the inherent properties of the raw coal and the mechanical processes within the furnace.The thermal stability of the raw coal can serve as an indicator for estimating the extent of particle fragmentation in the carbonization furnace.The prediction formula for the mass proportion of fine semi-coke during industrial production was determined,based on the thermal stability of raw coal.As the particle size of semi-coke decreases,the ash content initially decreases and then increases.The levels of SiO_(2)and Al_(2)O_(3)in the ash first increase and then decrease,while the CaO content follows a pattern of decreasing and then increasing.In medium-sized semi-coke,the SiO_(2)and Al_(2)O_(3)content is highest,with CaO content being the lowest.The ash yield of semi-coke is influenced by both the initial ash content of the raw coal and the extent of reaction that occurs during the production process in the retort furnace.The degree of semi-coke fragmentation exhibits a trend as the pyrolysis temperature rises,initially increasing,then decreasing,and subsequently increasing again.This behavior is attributed to the effects of volatilization and alterations in organic groups within the coal.