Investigation into the reasons for low yield in distillation systems
Thread Content
There are two distillation units with the same design parameters; they are identical to each other, with one being used for the first stage of distillation and the other for the second stage. The process packages and equipment used in the two phases are exactly the same. However, the yield of the second stage after operation is always low. All heat exchangers in Phase 2 were inspected to ensure no leaks. Removing the extraction and feed flow meters from Phase 2 and installing them on Phase 1 yielded similar data, indicating that there is no problem with the flow meters. The deviations between the feed rate, production rate, and the liquid level in the tank area are not significant. The vent volume of the non-condenser, the amount of fusel oil recovered, the amount of deionized water added, and the amount of residual liquid sent out remain roughly the same as those under the same load as in Phase 1. But why can’t the yield in phase two be increased? Could it be that the orifice plate of the flow meter in Phase 2 was installed in the wrong direction on the pipeline? If it’s installed backwards, will there be no traffic or will the traffic be low? Let’s discuss together what factors contribute to low yields. {:3_57:}
Why isn’t anyone coming? It’s okay, everyone come and share your opinions
Well, I guess I’ll have to add more to my own post. Although there are people who read it, no one comments, which is a bit disappointing. Here, I’ll first summarize some of my experiences to serve as a starting point; I hope everyone will share their thoughts widely. This is my personal opinion for reference only; please feel free to point out any errors: Reasons for the low yield in the distillation unit: 1. The amount of vent gas from the pre-condenser is too high, resulting in a significant loss of methanol ； 2. The accuracy of orifice plate flow meters: in some cases, there is a problem of reverse installation, while in others it’s a balanced-type meter that may not be designed for two-way measurement from the factory; furthermore, some flow meters give inaccurate readings due to pipeline pressure, requiring timely adjustment of the valve opening rate leading to the distillation tank. 3. Leaks in pipeline equipment go unnoticed for a long time: many of the drainage pipes in distillation units are buried and lead to underground tanks; if these buried pipes corrode and leak, it’s difficult to locate the source of the leakage. 4. The amount of fusel oils extracted is too high, and the crude methanol contains a high level of impurities ； 5. The reflux ratio is too high ； 6. The methanol content in the residue is kept at a high level ； 7. The product’s performance is poor when the vehicle has just been started ；