Discussion on the induced condensation process in the production of LLDPE using gas-phase fluidized beds
Thread Content
This post was last edited by 276957697 on 2011-7-17 22:17. Experts, please discuss the induced condensation process in gas-phase fluidized bed systems for producing LLDPE, and how to safely pass through the slurry zone when starting and ending this process. One additional point: the slurry zone is the area in the circulating gas where the condensate content ranges from 0-3%. When transitioning from dry gas operation to condensation operation, and vice versa, it is necessary to pass through this area, which is known as the slurry zone. It is the area where mass amounts of resin are produced in clusters.
Hehe, we just live our lives normally without any special procedures; it’s enough to add a catalyst when the temperature reaches around 46 degrees and the dew point is close to that value
Reply to 2# 8914329: What if, after adding the catalyst and letting the reaction proceed for a while, the condenser is added later? How should that be done?
Methods for achieving condensation include: 1. increasing the catalyst, 2. increasing the condensing agent
I think the most important aspect of this issue is dew point control, which is extremely vital. Temperature control at the outlet of the recycle gas condenser and temperature control in the reactor are also crucial. Dew point control is key to carrying out operations in a condensed state; it also helps with the addition of catalysts and the adjustment of materials. All these elements need to be coordinated properly, otherwise operational difficulties and difficulty in controlling the reaction will arise
One of the key operations in the induced condensation technique is to quickly enter the condensation mode within a range of 3 degrees above and below the dew point, in order to avoid operating at the dew point； Theoretically, there are various methods of operation: 1) increasing the amount of catalyst added (an appropriate excess can be used based on the catalyst’s activity), 2) reducing the reactor pressure by 50–200 kPa. 3. Reduce the circulating gas flow rate by 5–15%. 4. Slightly increase the ethylene partial pressure by 50–100 kPa. 5. Slightly reduce the reactor temperature by 2–3°C. However, in actual production, it is common to increase the amount of catalyst used, thereby increasing the yield.
Increase the amount of catalyst quickly to raise the reaction load, thereby rapidly lowering the inlet temperature and allowing quick passage through this range – that’s the practical approach! Of course, there are other aspects to the theory, but they are generally not used in practice