直立内热干馏炉所产不同粒度半焦的组成与结构特征

针对现有直立内热式干馏炉不同粒级半焦产物进行深入分析有助于认识原煤在炉内的热解反应行为和物料在炉内的运动与破碎等物理变化规律,采用国标方法研究了5座相同工业规模的直立内热干馏炉所产半焦的粒度分布、工业分析与发热量、有害元素与无机矿物组成情况,分别采用N₂吸附法和Raman光谱法测定了不同粒度半焦的孔隙分布与碳化学结构特征,并结合生产工艺分析了不同粒级半焦性质差异产生的可能原因。结果表明:13mm~25mm和6mm~13mm粒级在干馏炉所产半焦中占比最高,原煤的热稳定性是影响干馏炉内粒度降解的最重要因素;随着半焦粒度降低,受热解程度和矿物质作用共同影响,挥发分和灰分先降低后增高;小粒度半焦灰分中较高的碳酸盐降低了其发热量;小粒度半焦中全硫含量最高,各种形态硫随粒级变化规律不同;N、P和Cl元素在不同粒级半焦中无明显分布规律;随着粒度降低,CaO含量先降低后提高,而SiO₂含量先增高后降低;半焦中料和小料的孔隙结构最发达,碳结构有序化程度最高。

Composition and Structure Characteristics of Semi-coke with Different Particle Size Preparing from Vertical and Internal Heating Pyrolyzer

Investigation on the semi-coke products with different particle sizes in the existing vertical&internal-heating pyrolyzer is significant to understand the pyrolysis reaction behavior and the material movement and fragmentation characteristics of the raw coal.The particle size distribution,proximate analysis,heating value,harmful elements,and inorganic mineral composition of the semi-cokes produced in five industrial-scale vertical&internal-heating pyrolyzers were studied by adopting the national standard method.The pore distribution and carbon chemical structure characteristics of semi-coke with different particle sizes were investigated by N₂ adsorption method and Raman spectroscopy,respectively,and the mechanisms for the differences in the properties of different particle sizes were analyzed by combining the production process of semi-coke.The result shows that the semi-coke with particle sizes of 13mm-25mm and 6mm-13mm account for the largest proportion of the semi-coke produced by the retort,thermal stability of raw coal is the most important factor which can influence the degradation of particle size in the pyrolyzer.With the reduction of semi-coke particle size,the fractions of volatile and ash decrease first and then increase due to the degree of pyrolysis and mineral matters.The high content of carbonate in the ash of semi-coke with small particle sizes reduces the heating value.The highest total sulfur content is obtained in the semi-coke with small particle sizes,and the forms of sulfur vary with the particle size of the semi-coke.The distributions of N,P,and Cl elements show irregularity with the particle size of the semi-coke.With the decrease of particle size,the fraction of CaO decreases first and then increases,while the fraction of SiO₂ increases first and then decreases.The pore structure of the semi-coke with medium and small particle size is fully developed,and the ordering of the carbon structure is improved.