Some issues regarding the operation of the domestically produced PK301 in polypropylene plants
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Dear all**, I would like to know if any of you have labyrinth-type propylene recycle gas compressors for domestic PP plants. How is your usage? We are using a labyrinth-type compressor manufactured by a domestic company, and its performance is not very satisfactory. The main issues are as follows: 1. Hydrocarbons tend to enter the crankcase initially, which causes the lubricating oil’s flash point and viscosity to decrease, preventing long-term operation. Post-modification: Zhongti added an oil drainage line, replaced the inert gas with propylene gas, and changed the lubricating oil from L-DAB150 to GeGao 150 (synthetic oil). It works normally after running. 2. The compressor contains a large amount of oil and dust, and this issue cannot be completely resolved. After taking measures, the situation improved slightly but not significantly: a new filter F303 (with a precision of 10 UM) was added after D304. The several buffer tanks of the compressor and D304 are drained regularly. When producing products with high and low melt indices, the amount of oil discharged is not much; it is slightly more for those with high melt indices. 3. The performance of the air valve has been poor since 2016 (it was not ideal even before, with a maximum operational time of nearly 4 months); now its lifespan is around half a month to 2 months. Domestic gas valves or domestically repaired gas valves. 16 years ago, when air valves were disassembled, inspected, and replaced, springs and valve discs rarely broke, but this phenomenon has occurred frequently since this year. The device load also increased last year; it was generally 80–95% last year, while this year it is 90–110%. We believe that the operating condition of the gas valve is also related to the load; an increase in the circulation rate leads to an increase in the total amount of impurities in the circulating gas per unit time, and it is not ruled out that there may be quality issues with the gas valve. Some modifications have been made to the currently used domestic new gas valves, and their effectiveness remains to be tested. I would like to ask the experts: how is your operation going? Has a situation like ours occurred before? How was it solved?
We also have two labyrinth compressors for our polypropylene production; they are from YuanDa, and they are working well
The isolating gas we use is also propylene; please check the issues related to the process. 1. You can replace the filter element with one of 5UM rating – the presence of powder indicates that the filter element’s filtering efficiency is poor or that it is damaged. 2. In the case of oil presence, check how often the T302 oil needs to be replaced; high oil temperatures may be a factor. 3. Also check whether the flash point of 163 is too high. 4. What is contained in the main circulating gas of these oil-containing tanks?
We produce polypropylene via the gas-phase method. There is an F303 unit before K301, but no oil washing tower. It worked well in the past, yet since October this year it has become impossible to produce grades with unstable properties. In the first few instances, it was the F303 unit that failed, and the filter at the inlet of K301 became clogged, filled entirely with alumina. Later, there was another high-temperature alarm from the secondary compressor; upon inspection, it was found that one of the air valves was damaged. After switching to a different grade of material, the temperature remained slightly higher than before, but production is still being carried on for now. . . The water content measured in F303 has also been consistently around 10 ppm higher, but the water content of the raw material is normal. . . I need expert advice. . . :Q:Q:Q:(:(:(
The same is true for our PK301 unit; after the increase in load this year, there has been severe contamination of the gas with powder, and gas valve problems have occurred frequently. It might be related to the manufacturing process
I used a Japanese one; there was no problem at all.
The phenomenon mentioned by the original poster has also occurred in our device; it’s very familiar
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