Reasons why vacuum cannot be applied
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Our plant uses two steam jet pumps to evacuate the tower, but during the initial operation it was found that a sufficient vacuum level could not be achieved. The inspection showed that the jet pump was not clogged either, but the temperature of its inlet pipe was high, higher than the temperature of the pipe coming from the condenser. It is currently suspected that there is a problem with the vacuum pump design; any member with experience in this area, please share your thoughts.
The inlet temperature of the vacuum pump should be the outlet temperature of the condenser. Based on what you’ve described, I suspect there’s a problem with the pipe connections; it’s possible that the steam pipe and the exhaust pipe are connected incorrectly.
The outlet pipeline of the vacuum pump should have an enlarged diameter, and the straight section should be long. Has the tower been subjected to a gas-tightness test? What material are the gaskets used in towers and pipelines? It is recommended that you use gaskets made of expanded PTFE. My propylene dehydration tower also had this problem at first; it was later found that the reboiler was leaking.
Based on the poster’s description, it seems to be a problem with the vacuum pump (unless it’s the wrong pipe connection as mentioned by the friend on the 2nd floor).
Based on what the poster has described, it is not necessarily a problem with the injector. Regarding the phenomenon that \"the temperature of the inlet pipe of the jet pump is higher, higher than that of the pipe coming from the condenser,\" why is this? I would suggest: 1. Check how effective the condensation is in the inlet condenser of the jet pump? Whether the design requirements have been met. 2. Check whether there is any blockage in the outlet pipeline of the jet pump.
If the vacuum pump is fine, consider the condenser. This thing has a significant impact on the condensation efficiency of the condenser. If there is a slight leak of steam in the reboiler, it has little impact, as steam can condense.
Reduce the evaporation rate at the bottom of the tower and lower the pressure of the steam injected
If it is the first time using an empty tower, it is recommended that you introduce a small amount of steam to give it a try.
It is likely that the volume of vapor flowing in is too large; it is recommended to add a condenser (to condense the water present in the feed gas). Since you are using steam for injection, water can be used instead, as it can serve the purpose of condensation, which will greatly improve the efficiency of the steam injection pump
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First, the inlet temperature of the vacuum pump is high; the issue of the water cooler needs to be considered. Second, it is necessary to check whether there are any leaks in the system. Third, the vapor load on the tower itself is too high, exceeding the processing capacity of the vacuum pump.
It is recommended that you use water to absorb the gas
Suspicion 1. The condensing efficiency of the condenser is poor; the steam is not fully condensed, which directly results in an inability to create a vacuum. Adjust the process to solve it. 2. There is a problem with the system sealing. Check for gaps 3. Are the two pumps connected in series or in parallel? It should be connected in parallel
I’m not sure about your manufacturing process; should vacuum be applied first before feeding in the material?
There is a problem with the pipe connections; the steam pipe and the exhaust pipe may be connected incorrectly
First, check whether there are any issues with the piping of the process pipelines. As mentioned on the second floor, when the piping is connected incorrectly, our company detects this problem before starting up the equipment; for example, the steam pipes and the material pipes might be connected in the wrong way. If there are no such problems, then stop the operation and conduct a leak test to ensure that the system isn’t leaking, as this could prevent the creation of a vacuum. If the leak test shows no problems, then check the cooling efficiency of the cooler before the steam injector, and also examine the cooler after the steam injector for any issues. In the cases I’ve encountered, if the cooler after the steam injector doesn’t work properly, it can also prevent the creation of a vacuum. If everything else is fine and steam can be supplied normally, then the problem lies with the steam injector itself
There must be a problem with the vacuum pump, unless the pipes are connected incorrectly