Demisters

[scorcher]

Our plant burns liquid sulphur to produce SO2 to be fed directally to another plant on site.
The SO2 is cooled initially in a waste heat boiler, then further cooled to around 160C as the transfer pipe supplies it to a final packed tower.
This tower contacts the gas stream with 98% acid to remove any SO3. The top of the tower has about has a meter of 1" packing acting as a demister, before the gas, now cooled to about 60 is passed to a packed tower on the next process.

We know there is significent entrainment/mist in the exit stream from the tower. As i understand it, if the mist is entrainment, the patricles will be easily removed by a demister knitted pad, however, if it is acid mist, we will need a coaleaser or candle filter.

The aim is to reduce the mass of acid carried over, rather than remove every last drop of liquid. What might be the most cost effective solution.
What methods of determining droplet size are available?
THanks
Scorcher

 

[MariusChE]

Lower the temperature in a shell&tube heat exchanger. This will reduce the gas volume, reduce the partial pressure and give you some surface area to work with for coallescence. Droplet size is difficult to determine because they coallesce. If it is SO important then you might want to try iso-kinetic sampling over a cryogenig, immiscible fluid such as a low molar mass aliphatic oil at -4°C or so. Cost is always a consideration but I think that you can do this cheaply at low pressures. How do you propose to separate the acid from the "other" liquid? The liquids are miscible...water and acid. You would have to remove both at the same time.

remove.marius_che@yahoo.com

 

[Kemical]

Scorcher,
i am really intersted in the process of your plant, a bit strange to me, converting Sulfur to SO2,

can you tell me more about the products you extracted at the end of your process plant?

if you have any related information about the process overall, it would be highly beneficial.

thank you in advance.

Regards.

 

[krossview]

Dear Scorcher,

I recommend you contact some of the mistex vendors like ACS, Koch/Glitsch or Nutter to see if a Vane pack (Dixxon plates) is effective in reducing the amount of entrained liquid particles. A knitted demister in this service has a better removal efficiency, but clogs up easier than a mistex pad. The vendor can tell you what particle size are carried over, likely below the 10 micron range, Unfortunately this does not remove the smaller mist particles.

Good luck

Krossview, OK