煤气化熔渣高温结构演变及其对粘温特性影响的机理研究

The viscosity-temperature performance of coal ash slags in entrained flow gasifier has a direct relationship with their structure evolution under high temperature. The study of structure of slags can provide a good guidance for improving the fluidity. This research will investigate the structure evolution as well as viscosity-temperature property experimentally, numerically and theoretically. For the structure, the solid-state nuclear magnetic resonance (SS-NMR) and molecular dynamics will be combined to study the distribution of different degrees of polymerization (Qn microstructures) and ratio Bridge Oxygen(BO)/Non Bridge Oxygen(NBO). Then the ratios of main components in the coal ash slag will be changed to study the mechanisms of components on the structure. As for the viscosity-temperature performance, the high-temperature viscometer and X-ray Diffraction(XRD) will be used to measure the viscosity and crystalline phases. At last, the relationship between structure and viscosity evolution as well as the critical viscosity will be analyzed, which explains the influence mechanism of components on viscosity. A final structurally-based viscosity model will be established which could provide basic data and theoretical guidance for flux addition and coal blending in operation of gasifier.

气流床气化炉内熔渣的粘温特性与熔渣的结构密切相关，研究熔渣结构的演变对改善气化熔渣粘温特性有着重要的意义。本课题拟采用实验研究、数值模拟和理论分析结合，分别对熔渣高温下的结构演变和宏观粘温特性进行研究，建立二者之间的联系。在结构方面，采用固态核磁共振仪和分子动力学模拟对熔渣进行结构测量，分析熔渣内不同网络聚合度(Qn)的分布和桥氧/非桥氧的比例，并改变煤灰的主要组分，研究不同组分对结构的影响；在粘温特性方面，主要采用高温粘度计和X射线衍射测试获得对应组分的粘温特性和析出的晶相。最后，分析熔渣结构的变化与粘度以及粘度突变处的联系，阐释不同组分对熔渣粘温特性的作用机理，建立基于结构的粘温预测模型，为工程上添加剂、配煤等提供基础依据和理论指导。

气流床气化炉内熔渣的粘温特性与熔渣的结构密切相关，研究熔渣结构的演变对改善气化熔渣粘温特性有着重要的意义。本课题采用NMR实验研究、MD数值模拟和理论分析相结合的方法，分别对熔渣高温下的结构演变和宏观粘温特性进行研究，建立二者之间的联系。在结构方面，采用固态核磁共振仪和分子动力学模拟对熔渣进行结构测量，分析熔渣内不同网络聚合度(Qn)的分布和桥氧/非桥氧的连接方式，然后改变煤灰的主要组分，研究不同组分对结构的影响；在粘温特性方面，主要采用高温粘度计和XRD获得对应组分的粘温特性和析出的晶相。最后，分析熔渣结构的变化与粘度和粘度突变处的联系，在大量黏度数据的基础上，创新性地开发了一套基于微观结构的粘度模型，并与实验结果和前人的模型进行了对比，为煤气化工程应用中添加剂和配煤提供了基础依据和理论指导。