超临界水煤气化过程换热器沉积状况数值模拟研究;

Numerical modeling of deposition condition in heat exchanger for coal gasification in supercritical water

建立了超临界水煤气化换热器在超临界水与煤颗粒体系下的三维瞬态CFD模型,利用IAPWS物性数据库计算超临界水的物性,应用CFX软件模拟研究了竖直放置的超临界水煤气化管壳式换热器的管箱在不同进料条件和换热器结构下的沉积状况并对其结构进行了优化。利用已有的实验结果对模型进行了验证。研究表明,立式换热器管箱垂直进料在减少颗粒沉积方面优于侧边进料和倾斜进料,合适的管箱高度可以减少颗粒的沉积,应尽量减少1mm以上的大颗粒的含量。研究结果对超临界水煤气化过程中使用的换热器的研究设计具有一定的理论意义和工程实用价值。

A 3D model of shell and tube heat exchanger used in super critical water coal gasification was established including supercritical phase and solid phases. IAPWS data base has been used to simulate the physical properties of supercritical water. Numerical simulation was studied adopting CFX in terms of deposition condition under varied feed and different structure of vertical heat exchanger tube box and the structure of the exchanger was optimized. The model has been validated by experiment results. The results showed that vertical inlet type was better than the other type and proper height of the tube box could reduce the deposition mass. The percentage of the particle whose size larger than 1 mm should be reduced to the greatest extent. The results provided significant guide to the design of the heat exchanger in supercritical water coal gasification process.