Shenhua Coal-to-Oil Baotou Coal Chemical Company Achieves \"Seamless\" Switching Between Imported and Domestic Catalysts

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Shenhua Coal-to-Oil Baotou Coal Chemical Company Achieves \"Seamless\" Switching Between Imported and Domestic Catalysts Author/Source: Date: 2016-12-02 Clicks: 7 Recently, Baotou Coal Chemical Company managed to make a seamless switch from the imported catalyst SHAC201 to the domestic catalyst SUG, without any disruptions in its performance parameters. This achievement marks an important breakthrough in the stable use of domestic catalysts by the company, and it represents a significant milestone in its efforts to advance technological innovation. Daring to innovate and skilled in calculation to achieve a “seamless” transition in product quality. Due to the significant difference in hydrogen tuning properties between domestic and imported catalysts, when producing the same melt index, the hydrogen-to-propylene ratio for imported catalysts is around 0.3–0.35, whereas that for domestic catalysts is around 0.55–0.8. This results in a large amount of intermediate material with a melt index that does not meet the requirements during the switching between the two types of catalysts. In line with the company’s strategic goals of \"technological innovation and efficiency improvement,\" the relevant technical staff carefully studied the reaction processes of the two catalysts. By determining the residence time of the powder in the bed, they calculated the proportion of powder produced by each catalyst in the bed, thereby identifying the optimal hydrogen-to-propylene ratio required for a given melt index at each time period. During the past two switches from domestic to imported catalysts, the fluctuations in the melt index remained within acceptable limits, and no transitional material was generated during either switch. Make bold adjustments to fine control, achieving a “seamless” transition in catalyst activity. Due to differences in production processes, there is a significant difference in activity between imported catalysts and domestically produced catalysts. The activity of imported catalysts remains relatively stable per batch; they exhibit rapid reaction kinetics, but have poor electrostatic control, making high-load operation difficult ； Domestic catalysts have high activity, low ash content in the products, and good static electricity control, but their activity is unstable and the adjustment is rather delayed. To ensure stable production after catalyst switching, the relevant technical personnel conducted numerous experiments, continuously adjusting parameters such as reaction temperature, gas flow rate in the cycle, bed weight, propylene partial pressure, and AL/SI, **which helped to reduce the fluctuations in various reaction parameters during the switching process, thereby laying the foundation for high-load, long-duration operation. Careful planning in advance ensures a \"seamless\" transition in the packing density of the powder. There is a significant difference in the bulk density of the powder produced by imported catalysts and domestically produced catalysts. When producing polyolefin products of the same grade, the bulk density of the powder obtained using the imported catalyst SHAC201 is between 270–310 kg/m3, whereas that of the powder produced using the domestic catalyst SUG is around 390–410 kg/m3. This results in a large difference between the set load and the actual load in the granulation system. To reduce discrepancies and prevent the granulation system from shutting down due to excessive load or low levels in the degassing chamber, relevant technical personnel developed a detailed operating plan. First, the time at which powder with a high packing density enters the degassing chamber is determined based on changes in the reactor’s fluidization density. By estimating the residence time of the powder in the degassing chamber and taking into account the actual torque of the granulator, the density settings for both the granulator and the additives are increased gradually in advance, thereby maintaining a stable level of material in the degassing chamber and ensuring consistent product quality. This approach prevents issues such as fluctuations in the rotating discharge valve, shutdown of the granulator due to high torque, and poor product quality that can occur when powder with a high packing density enters the granulator, thus laying a solid foundation for operation that is safe, stable, efficient, and of high quality.