Vents to Knockout Pot Issues

[Bourbon103]

Hi All,

We have a knockoutpot which takes in multiple reactor vapor vents (typically set to 1 psig or a few oz's) from a different building. Each vent line typically connects vents from multiple reactor sources. Great pains have been taken to ensure that for each vent line to the knockoutpot, the vapors from the reactors it connects will not react unfavorably on their way to the knockout pot (i.e. form precipitates that block lines).

We have a few existing problems with the system:

1. Vent lines are plugging.
2. The pressure in the knockout pot is at times greater than the pressure within the vent lines.

We think that the greater pressure in the knockout pot is pushing vapors back into lines that they aren't supposed to be in (e.g. TiCl4) and causing the precipitates and plugging.

Any thoughts? Is there a backflow prevention method, local to the knockout pot, that would ensure the vents wouldn't back vapor into the vent lines, or is the only solution another knockout pot to maintain the seperation of vapors?

Thanks again.

 

[mbt22]

Is there some form of inert fluid you could use in a seal pot? If temperatures and reactivity allow, a dip tube into a liquid may give you a few tens of millibars static dP. This assumes that the back pressure from the pot is less than this.

The other possibility may be to increase the size of the vent from the pot to atmosphere/flare or wherever it is going. Less backpressure to the pot may solve your problem, or reduce it to the point where the above seal pot is viable.

Do you have analysis of any of the precipitate to confirm the sources of material?

 

[MikeClay]

A few more thoughts:

Is it possible to have vents from different buildings flowing at the same time? This would not be good due to possible plugging in the seal pot vent.

If backflow in a non flowing line is a problem, an inert gas purge at each building might prevent line plugging.

The liquid seal that mbt22 suggests would work if the liquid level can overcome the backpressure. Be carefull that precipitates don't form in the liquid and also lead to plugging.

Combining reacting materials in the same vent system is not the best thing to do. Separate KO pots seems like a good idea to me.

--Mike--

 

[jamesbanda]

Have you considered using an eductor system to raise the pressures ?

You can either use a water powered eductor (remeber those chemistry filter classes) or a air or nitrogen powered one..
or steam.