煤中羧酸钠诱发CFB气化煤灰结渣机理及调控机制

气化炉炉膛底部和返料器煤灰结渣是制约高钠煤大规模循环流化床（CFB）气化利用的“瓶颈”问题。前期研究发现煤中羧酸钠（包括分解产物）是煤灰结渣显著性影响因素。目前关于羧酸钠对结渣特性影响的专项研究尚处于空白状态，与结渣特性密切相关的高钠煤灰熔融过程动态分析还鲜有报道。本项目拟聚焦煤中羧酸钠，将煤灰熔融过程动态分析方法引入结渣性研究中，结合多种物相分析及热力学计算方法，明确羧酸钠与石英、勃姆石、高岭土的反应机理及产物熔融行为；建立适合CFB气化煤种结渣性定量评价的方法；揭示羧酸钠对高硅铝、高硅铝比、高钙、高铁等典型煤灰熔融和结渣特性的影响及差异性；通过结渣特性和熔融特性的关联性分析，阐明羧酸钠诱发煤灰结渣的机理；探明循环物料中煤焦存在对高钠煤灰结渣性的双重影响及机理；据此，提出配煤煤种或阻熔剂选择及掺混比例确定的原则和方法。研究工作有望为高钠煤CFB气化防结渣技术开发提供一定的理论指导。

The severe ash slagging was encountered at the bottom and loop seal of gasifier, which was the ‘neck bottle’ problem to restrict the large-scale utilization of sodium rich coal by CFB gasification. Previous studies had found that sodium carboxylate in coal was the significant factor to the ash slagging characteristics. However, the reports focused on the effect of sodium carboxylate is still a blank by now. Furthermore, the reports on the dynamic analysis of sodium-rich ash melting process, closely related to the ash slagging behavior, is relatively few. In this work, we will focus on the sodium carboxylate in coal. The dynamic analysis of coal ash melting process are introduced. Some phase analysis and thermodynamic equilibrium calculation are adopted as well. The aim is: to illustrate the reaction mechanisms between sodium carboxylate and quartz, boehmite, kaolinite as well as the melting features of products; to build a quantitative method to evaluate CFB ash slagging behaviors; to understand the effect of sodium carboxylate on ash slagging characteristics of some typical ashes such as high Si and Al, ratio of Si/Al, Ca and Fe ashes and the difference. Furthermore, by correlating the ash slagging and melting characteristics, the induced mechanisms of sodium carboxylate on the ash slagging characteristics is well illustrated. Meanwhile, the effect of char in recycle materials on the ash slagging characteristics is further explored. Based on the results, the method and principle to select the suitable mineral inhibitor or blending coal as well as blending ratio are proposed. This research is expected to provide some fundamental guidance to the development of ash anti-slagging technology.