Reasons for lumps occurring after the start-up of the SPGⅡ process for the continuous polymerization of domestic polypropylene
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Our company’s polypropylene plant has been put back into operation, and the second reactor experienced an increase in motor current as well as a blockage in the discharge valve. Upon opening the reactor, it was found that there were some lumps inside it. Once the plant stopped operating, the levels of propylene, water, sulfur, and other impurities were all within acceptable limits. Could someone please advise on what caused this issue and how it can be prevented?
The SPG process is used to produce powder, so how is it producing solid blocks?
Polypropylene caking is an inherent phenomenon in propylene polymerization; hot spots occur, which lead to caking. Many processes lead to caking; however, as catalysts and process technologies become more advanced and operating techniques improve, caking occurs less frequently. In polymerization as a whole, especially free-radical polymerization, the most fundamental aspect is to control the reaction rate, prevent the formation of local hot spots, and avoid caking. There are many reasons for caking in polypropylene, including catalysts, process flows, equipment, and process operations, among others.
If the discharge valve is clogged, creating a dead spot, lumps will form. Hotspots had already formed even before the blockage.
Zibo Haiyi? There’s a hotspot; for the second reactor, could it be an issue with the quench fluid?
It is likely caused by uneven local heat dissipation; it is recommended to check the heat removal from the equipment and the mixing process.