VOC removal through carbon absortion 2

[kiah]

We have an paint application room on steel strip and ventilate this room through use of fans to keep the VOC levels from solvents below exposure standards . On one of our plants this air (around 20 000cfm) is then passed to an incinerator fired with natural gas to destroy the VOC content. This costs millions of dollars annually to our business and creats a lot of greenhouse gases. We are considering a third plant and are looking for good practices but have been told using carbon absorption is not cost effective due to capex for this flowrate, and dealing with the waste VOC stream from steam or vacuum regeneration of the carbon.

Does anyone have other suggestions or contacts who may be able to point to working examples of technology other than incineration for this application at these high flowrates

solvents are typically aromatics (BTX), n-butanol, MEK and some acetone, but there is a wide variety depending on different paint types.

thanks
kiah

 

[BobPE]

what type of incenerator are you using? There really isnt much out there to deal with what you have efficiently. It doesnt seem like you have enough to use carbon and reclaim through regeneration which would be an ortion...

BobPE

 

[TrevorP]

You should at least consider a cryogenic abatement system. These are generally fairly expensive to purchase, but generally make use of a sites existing N2 supply for the cooling effect, assuming you have one. I suggest you contact Air Products or BOC for details. See

http://www.airproducts.com/cryogenics/solvent.asp

 

[vintage70]

These compounds can be easily scrubbed with water. You need to get the disposal cost for the water though. Unfortunately you are most likely generating a hazardous waste. Are you a generator now? That is do you have an EPA ID number as a large quantity generator. I apologize are you in the USA?

There are options and each one has a cost. Cheapest way out is to substitute the carriers to a less hazardous compound.

But a scrubber may be a good start.

 

[rbcoulter]

Look into bio-filters or catalytic oxidizers.

 

[kiah]

thanks for the replies, I will chase those other options,

BobPE
Our incinerators are MAXON type direct fire with temperature control to 700degC.

Vintage70
We are in Australia, and have EPA agreements for discharge of other hazardous waste, dealing with the waste stream isn't too hard as we have a bug plant on site for waters contaminated with this type of compound from the caol and coke plant.

kiah

 

[phoward]

This is a perfect application of dry powder painting. You eliminate the VOC entirely and get a better painted surface also. Do a web search for such and you will be plesantly surprised with all the options you have to make this work.

 

[gacguy]

Suggest you contact VARA Internaional in Vero Beach
(561) 567 1320 and ask them if their CADRE process is applicable?

This is a carbon adsorption- regeneration process which uses the hot gas from the thermal oxidizer, which is part of the package, to regenerate the bed.

 

[waterexpert]

Have you considered on site regenerated GAC filters? These can be far smaller than those designed for media bed replacement. As the previous post says, they can use waste heat where available, or alternatively steam can be used to recover the solvents where boiling points aren't too low.

Sutcliffe speakman offer these in the UK.

 

[PeterCTQ]

Your application is probably best dealt with using biofiltration or regenerative thermal oxidation. Biofiltration uses bacterial oxidation to degrade the VOC's. The RTO will oxidise using heat but has 95% heat recovery and so the operating costs will be much less than your current afterburner. Contact Clean TeQ in Australia for help.

 

[chicopee]

I have looked at regenerative thermal oxidizers for our paint bay (80'X 120') and the prospect seemed promising however our primer is zinc which is also sprayed on and the zinc will damage the regenerative thermal oxidizers. We had to cut down on the amount of paint to comply w/ EPA.
About reclaiming the heat for other purposes-that could save you a lot of money?
One possibility stated in the above comments about scrubbing w/ water should be further investigated with activated charcoal filters immersed in the scrubbing water. When the activated charcoal filters are loaded then you can clean them and burn the concentrated vapor.

 

[azertyuiop]

chicopee ,

Savings are obtained this way : your main RTO fuel burner doesn't have to stay burning at full or half capacity as in a catalitic oxidiser, because a lot of the combustion energy required to pre-heat up the organic gases is now delivered by those RTO heated up bed sections. If your organic material is very calorific , you may still have high enough exit gas temperature to install a heat exchanger after the RTO , in order to heat up another energy medium , that then can be used in another part of your process. I used this heat exchanger after the RTO , to heat up 38 000 Nm^3/h of fresh outside air to 350°C , air that then served to heat up a hot air oven , oven used to dry an impregnated glasfiberweb. I basically used the solvents evaporated in the hot air oven as a fuel for the whole process , saving on natural gas and saving on waste removal bills.

You could use this surplus hot air on the exhaust of the RTO to produce superheated steam or warm water for office building heating during winter . . .

 

[atiaran]

Biofiltration is a good option if you don't want the natural gas costs and additional secondary pollutants. For your components though, the efficiency will likely get no higher then 85% (versus an RTO getting 95+). ALso, if your acetone concentration is high, it can affect the pH in the biofilter system because of it's water solubility. My company has an installation at a similar facility, and the biofilter is having this problem because acetone is a major component in the paint they use.

The other components you listed would not pose a problem.

 

[jongwon03]

PLEASE REFER TO QVE/QBF SYSTEM WHICH WAS INVENTED BY Q-BIOTECH.,KOREAN VENTURE COMPANY. Since 2000, THIS SYSTEM HAVE BEEN BUILT IN MORE THAN TEN BIG PETROCHEMICAL PLANT IN KOREA. I WILL SEND THE REFERENCE PDF FILE FOR YOUR BETTER UNDERSTANDING. IF YOU HAVE ANY FURTHER INTEREST, PLEASE FEEL FREE TO CONTACT US AT kdwon@skevt.com.

Sincerely yours,
KD

 

[bobhearn11]

You may want to consider a regenerable zeolite adsorption system. Look at

http://www.munters.com

, I have seen these at semiconductor manufacturing plants.