VOC absorption

[sottocutaneo]

Hi all,
I want to know the state of art on VOC absorption. Can someone give me detailed information on existing facilities where the VOCs are removed with an absorption tower (and the absorbent liquid is regenrated with a stripper)?

Thanks all!

 

[dcasto]

It's called a lean oil plant. The ultimate lean oil plant is patented by AET Process®Nitrogen Rejection Unit.

 

[cheute79]

There are several suppliers and designs, mostly are small players, and have wisely limited themselves to specific industries or VOC types (such a acetates or ketones). The largest player is probably Sulzer ChemTech. Their headquarters is just outside Zurich, Switzerland. They have a N American office in New Orleans or Houston.

Be very careful with the technology. The absorbant liquids can hydrolyze or otherwise react very quickly in the wrong environment. My experience was with 2 such systems about 15 years ago, and the 2 suppliers didn't know about the reactivity or limitations of the chemistry. Sulzer had a pretty good feel for the issues.

 

[sottocutaneo]

thanks all

 

[willem79]

What kind of VOC's are we talking about and in what way do you want state of the art? maybe the most important: to what concentration do you want to reduce?

 

[sottocutaneo]

I am talking about hydrophobic VOC such as benzene.
For state of art I mean "used technology for VOC absorption".
I want to reduce to a concentration that complies with the law

 

[willem79]

Autch, Benzene... thats a tricky one (is perfectly solluble in water by the way, but a scrubber only solves one problem by creating another). here in Holland we have a lot of clients (I work for an engineering company) who have to addapt to new legislation bij 2010. venting at max 1 mg benzene/Nm3... Thats almost impossible with only an adsorber. a 2 bed carbon adsorber and a polishing unit (choose between a burner or an RTO or a Katalytic oxidiser) is the most efficient way to go. Be aware that benzene has a high heat of adsorption and easily creates hotspots (see the tread i started "thread798-247206").

 

[sottocutaneo]

I am talking about absorption, not adsorption

 

[willem79]

oops sorry for that... Oke I know a little about those two. We looked at the possibility to replace an old carbonbed adsorber by a scrubber (absorber). These thing normally get you a 90% removal rate. If designed realy good and at a turndown of less than 1:3 you could get to 95%. Not enough for benzene (atleast not in Holland). So it realy depends what your cource of VOC's is...

 

[SeanB]

What is the source of your VOC's? We are currently installing a Vapor Recovery Unit at a marine loading terminal to eliminate the VOC's that are released as a result of gasoline loading.

 

[mggkg]

If the VOCs Vapor Press.is less than 0.5mmHg at30dC,and is soluble in water, That will be removed by absorbing system.

Otherwise, I recommend RTO (Regenerative Thermal Oxidizer)

 

[OllieSmith]

I have used Petrogas Environmental Systems out of Texas for our Absorption VRU on our loading racks for chemicals and petroleum. We really have no problem with the systems and meet all requirements.

We have been using Lean Oil Absorbers on recovering BTEX for years on our gas wells and also get 99% recovery rate on benzene.

 

[sottocutaneo]

Thanks all for answer.
What is the absorber liquid used in Lean Oil Absorbers?

 

[dcasto]

A hydrocarbon mixture with a molecular weight of 100 to 180, depending on the VOC's and efficency required.