The abnormal level of the monomer tank caused the synthesis gas tank to tip over
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During the pressing process in the polymerization workshop, a malfunctioning level gauge in the monomer tank – clogged by plasticized fragments – caused the tank to be filled with liquid monomer, which then flowed back into the syngas holder and vaporized instantly, causing the holder to overflow. Have anyone else encountered a similar situation? How can it be improved to completely eliminate this safety hazard?
Install 2 level gauges; if you have production experience, you can predict in advance that frost will form on the pipelines.
Ugh, something similar happened with the level gauge in our recycled monomer tank as well, but the instrument technician said he couldn’t determine the cause of the problem with the gauge! The original poster reminded us; thank you.
This post was last edited by wang*neng on 2009-8-25 at 17:30. Can’t we just use a diaphragm-type remote transmission system? Flap-type systems get clogged easily and often give inaccurate readings.
During the pressing process in the polymerization workshop, the balance pipe on the monomer tank should be connected to the monomer storage tank itself, rather than to the gas holder. The vapor pressure in the monomer tank should be at least 0.3 MPa, while the pressure in the gas holder is only 400 mm of water column; therefore, it’s not acceptable even if the monomer tank isn’t full. It makes sense that your instruments don’t recognize any problems with the level gauges. Moreover, today’s remote-controlled level gauges are of the double-flange type with diaphragms, which prevent blockages caused by plasticized fragments. I think you should investigate the reasons for the operational issues instead of relying on what the front-line workers say
After the safety valve of our individual storage tanks, there is an air tank; before, the gas was released directly, but this was considered unsafe during safety inspections, so it was changed to connecting to an air tank instead! If the monomer tank becomes full, overpressure will cause the safety valve to activate, resulting in direct return to the gas holder and causing it to tip over. What’s the setup with your safety valves?
Isn’t your monomer drawn from a storage tank? Then isn’t there a balance pipe between that storage tank and the monomer storage tank? There has to be one; otherwise, wouldn’t pressure build up due to the lack of a feed tank? How could it fill up to such an extent that the pressure rises enough to trigger the safety valves? And then, where is the gas phase from the feed tank connected to?
There are two types of level measurement devices for the vinyl chloride monomer storage tank: diaphragm remote transmission and on-site magnetic plate level gauges, to ensure accurate liquid level measurement. Assuming the monomer tank is full, the pressure in the discharge parallel pipes is balanced with the pressure of the high-boiling system. The DCS operator can monitor the pressure in the monomer tank, which prevents the safety valve of the monomer tank from activating.
I think if the single-tank level is full, even if you can’t see the liquid level, it should be possible to detect this from the high boiling pressure, and it shouldn’t cause the gas tank to tip over.