Fiber mist eliminator candle

[tomek73]

Hi, I work in sulphonation plant. Main reaction involves SO3 reacting with DDB (dodecyl benzene) in tubular reactor giving LABSA (dodecyl benzene sulphonic acid).
There is a gas-liquid separation after reactor. Gas stream (air, SO2 and SO3 traces, H2SO4 mists and orgaic mists) enters Fiber mist eliminator candle where liquid mists get separated and clean gas (air) is discharged to the atmosphere.
Recently we changed old reactor with new one with larger capacity. Our Fibermist eliminator (Brink filter) gets plugged up too soon. In one big casing we have two candles (L ~ 2m, D ~ 30cm).

My question is: How do design new filter for given increacesd capacity ?
Or at least what are the variables that are involved in design. I know that filter efficiency increases with Temperature increase, lower velocity (longer residence time).

I checked meny books (Perry, Chem Eng volumes etc) and couldn't find any design procedure for Brink filters. I even tried Internet.

One way of thinking is to try to use existing case and try to squeze in more candles that have smaller diameter. But that involves lots of modification and am not sure if maintanance is capable of doing it.

If anyone could help we I would be very greatfull. Thx in advance !

Regards, Tom !

 

[rmw]

Leave the candle design to the pros. Contact Koch Industries.

http://www.kochind.com/industry/technology_products.asp

rmw

 

[tomek73]

I will leave it to professionals of course, but I would like at least to know how to do prelimenary design. I would like to check existing one and to see what kind of dimensions we need for new one. Some backed up calculations or proof would help me to persue management.

Thx !

 

[ApC2Kp]

tomek73,

There some newer designs of fiber 'packings' and configurations, including a dual element 'candle within a candle' geometry that increases capacity with same housing.

The Brinks mist eliminators are now from MECS. Inc.

http://www.mecsglobal.com

If your filters are plugging up too quickly, a pre-filter layer or mesh pad might be what is needed.

 

[fhmusa]

Candle Filters are too flow restrictive for increasing capacity,and are very susceptible to plugging and high DPs.
Specialty Mist eliminators, such as KIMRE Inc. can very satisfactorily reduce plugging, eliminate carryover and reduce DP, and/or increase capacities. Retrofits are very easily done, and will save energy and maintenance, over the life of the plant. SEE

http://www.kimre.com,

and review H2SO4 info on site (

http://www.kimre.com/publications/kimre_mist_eliminators.pdf).

 

[ash9144]

Having worked in H2SO4 plant I would advise against a Kimre pad. While it has lower dp it also doesn't remove droplets very well at all. Unless it was being used as a pretreater to the candles.

MECS (Monsanto Enviro Chem) is the best bet for candle mist eliminators. They can help with some different mesh weaves to possibly allow increased capacity.

If your tube sheet is large enough to accomodate more candles that would of course be the way to go.

The biggest design factor is going to be how much dp your process can handle.