Dry solid feeding characteristics by computational particle-fluid dynamics simulation at high pressure

Many devices in the chemical process operate at high pressure rather than atmospheric pressure. In the case of the gas phase reaction, a high pressure induces large gas density. Therefore, a greater amount of gas can be added, which leads to an increase in the production amount. Recently, the Integrated Gasification Combined Cycle (IGCC), which has been attracting attention due to its low carbon policy, has shown high efficiency as well as low SOx, NOx, and CO2 emissions compared to coal-fired power generation. However, the disadvantage of IGCC is its high cost compared to existing coal-fired power plants. Coal injection contributes about 43%-45% of the high cost of IGCC [1]. In the IGCC, it is necessary to inject coal from atmospheric pressure to high pressure; however, a general injection device cannot inject particles from atmospheric pressure to high pressure. This is due to the difficulty of injecting particles from atmospheric pressure to high pressure because the gas flows from a high pressure to a low pressure. In order to solve the problem of the backflow of gas, a lock hopper method is generally used when injecting particles from atmospheric pressure to high pressure. The advantage of the lock hopper method is that it can overcome a large pressure difference and can transfer the particles. However, the lock hopper method has disadvantages, since it is difficult to continuously inject particles because the pressurization and decompression must be repeatedly performed. Also, the lock hopper method requires equipment that is considerably large and relatively expensive in terms of construction and operating costs [2-5]. For example, in Shell’s IGCC plant in Buggenum, which the existing lock hopper method is used, the cost of the coal injection part is estimated to be about 0.1 billion dollar [1]. Accordingly, a high-pressure powder fuel injection device has been developed to replace the lock hopper method injection device [1]. Stamet and Rocketdyne are developing the posimetric pump and the dry solid pump, respectively [1].

In this study, the experiment was carried out for the case of an atmospheric pressure condition, and the total pressure drop is 10 bar. However, it is difficult to find the variables that may affect the higher pressures and injection rate. In addition, to check the wall erosion of the hose, the hose must be operated for a long time; therefore, the wall erosion needs to be predicted for validity analysis. Therefore, in this study, we predicted the solid transfer characteristics of a high-pressure powder injector by using computational particle fluid dynamics (CPFD) method using the multi-phase particle-in-cell (MPPIC) method.