CO_(2)浓度及配比对焦炭溶损特性影响

Effect of CO_(2) concentration and ratio on the dissolution loss characteristics of coke

研究块焦、粉焦混合焦炭在CO_(2)气氛下的反应特性可有效提高干熄焦质量、降低溶损率,故采用自制高温焦炭反应测定装置,研究不同粒径配比及不同浓度CO_(2)条件下的碳素溶损反应,结合光学显微镜分析及Coats-Redfern法探讨了混合不同粒径干熄焦的溶损机理。结果表明,不同浓度下粉焦比例增加,粉焦溶损率为混合焦炭溶损率的0.7~0.9倍,较多CO_(2)与粉焦发生碳溶反应,导致块焦-粉焦混合焦炭溶损率随粉焦比例增加而增加。但在不同浓度下块焦和粉焦的各向同性组织含量降低而各向异性组织含量明显增加,其中,粉焦各向异性指数高于块焦,且平均增长4%,其反应活性也高于块焦,反应活化能随CO_(2)浓度、粉焦比例的增加而降低;且同一浓度下,焦炭中粉焦比例越多,碳溶反应越易进行。在低浓度下,粉焦比例对混合焦炭溶损率有显著影响,随粉焦比例增加活化能降幅最大为30%。研究结果可为进一步降低干熄焦溶损率提供理论依据。

The reaction properties of coke mixed with lump coke or powder coke in a CO_(2) environment could successfully lower the rate of dissolving loss and enhance the quality of dry quenched coke.In order to investigate the dissolution loss mechanism of dry quenched coke mixed with different particle sizes,a homemade high-temperature coke reaction measurement device was used to study the dissolution loss reaction of carbon under various particle size ratios and different concentrations of CO_(2).The optical microscope analysis combined with the Coats-Redfern method were used to investigate the dissolution mechanism of dry-quenching coke with different particle sizes.The results indicate that the proportion of powder coke increases at various concentrations,that the powder coke dissolution loss rate is roughly 0.7-0.9 times that of the mixed coke,and that more CO_(2) reacts with the powder coke to produce a reactive carbon-solvation reaction,which increases the mixed coke dissolution loss rate of lump coke-powder coke as the proportion of powder coke increases.However,the isotropy of lump coke and powder coke decreases while the amount of anisotropic tissue increases significantly at different concentrations.In particular,the anisotropic tissue value of powder coke is on average 4%higher than that of lump coke,and it is more reactive.The activation energy of the reaction also decreases as the concentration of CO_(2) and the proportion of powder coke increase.The more powder coke there is in the coke at a given concentration,the more likely it is that the carbon-solvation reaction will occur.The amount of powder coke has a major impact on the rate at which mixed coke dissolves at low concentrations.The highest reduction in activation energy that occurs as the amount of powder coke increases is 30%.The research findings may offer a theoretical foundation for further reducing the dissolution loss rate of dry quenched coke.