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Ventgas having low odor threshold

Ventgas having low odor threshold

Ventgas having low odor threshold

(OP)
Hello there

Currently we have a Client processing lignosulfonates for carbon black production. Client is seeking for means to stop long-lead complaints about nasty odor. Client considers those lignosulfates are a source of problem.

Currently we have some doubts:

Option 1 - Incineration
Measure: We can collect ventgas from lignosulfonates storage tanks and route it to an incinerator where the flue gas from the carbon black reactors is afterburned.
Doubts: Tanks are located far enough from incinerator and Client will get a long pipe with stagnant flow (clogging, corrosion, undetectable sucking of air). Flue gas will be able to backflow to vent pipe during "intake" breath of tanks (corrosion, clogging).

Option 2 - Absorbtion.
Measure: We can provide a water scrubber (packing or liquid-seal).
Doubts: Force circulation of water through packing and friquent replacing of water in scrubber (expenses). Spent water is a source of the odor (risk of fail).

Option 3 - Adsorbtion
Measure: We can provide an activated carbon filter.
Dounts: Activated carbon is prone to self-ignition (safety). It is hard to be controlled (reliability, human factor). Activated carbon is not be able to provide complete cleaning (risk of fail).

Option 4 - Dispersion
Measure: We can provide a new vent stack or to route ventgas to flue gas stack.
Doubts: Client has been receiving recurring complaints from up to 10 km away from tanks (risk of fail). It is hard to believe that those are a consequence of inadequate dispersion.

Option 5 - Inerting
Measure: We can provide inert gas pad or purging.
Doubts: Inerting will not prevent vaporizing of lignosulfonates as Client considers odor is a consequence of a fermentation (risk of fail). A possible source of nitrogen is located far enough therefore Client will get a long pipe with stagnant flow (corrosion, clogging, undetectable leacking of inert gas). Rather high cost of nitrogen (expenses).

Any thoughts, ideas, experience and documents concerning the issue are appreciated.

RE: Ventgas having low odor threshold

Hi,

Consider this link : https://www.researchgate.net/publication/233688034...
My experience with smelly chemicals (acrylic esters at ppb level) is bio filtration , activated carbon and wet scrubber (water and caustic soda solution).

https://www.enexio-water-technologies.com/solution...

Sharing with us the quantity to be treated and contamination level will help .

The most efficient will be the biofilter , definitely the most expensive technology (capex) which request a big footprint .
AC is also an option but need a continuous monitoring of the temperature of the bed ( Self ignition) and ability to treat the spent AC.
Wet scrubber requires the need to dispose the spent solution and a continuous monitoring of the solution.
In some countries like Chine a continuous monitoring of off gas is also required ( Chromatography) .

I'm aware of people using chemicals (spray) to cover industrially the odor .
Btw you should consult local EPA about the regulation and technology requirement .

note : typo Absorption ,Adsorption .

Good luck
Pierre



RE: Ventgas having low odor threshold

We currently take a two-step approach for our organics that have 30-100 ppb odor thresholds - a packed bed liquid scrubber followed by a thermal oxidizer. For this setup, incoming VoC levels are on the order of 5,000-10,000 ppm. After both stages, exit concentration is around 5-30 ppm. The gas is vented through a stack for dispersal, and is effective enough that no odor is detectible by on-site personnel or by the surrounding community.

Past experience suggests with other setups suggests that liquid scrubbing alone isn’t sufficient for odor elimination, as it is not economical to achieve high efficiency liquid scrubbing compared to thermal destruction.

Other places successfully use carbon beds, but you need to watch out for bed temps if loading is high to avoid self-ignition from the heat of adsorption.

I would vote for either a combination of 1,2, and 4 or a combination of 3 and 4.

Option 4 with dispersion doesn’t work by itself, but does work wonders when combined with a scrubbing system that will likely need to be 98%+ efficient.

Look at your VoC level in your vapor stream to determine % efficiency needed. Watch out if levels approach the LEL when considering thermal oxidation.

Work with experts when specifying these scrubbing systems, and get performance guarantees!

Lastly, installing a new stack may trigger regulatory requirements. Check with a knowledgeable person on how this plan interacts with state and local regulations.

Edit: On further consideration, be careful if exploring thermal destruction. Oxidizing these lignosulfates will result in the production of SOx (SO2/SO3), which are usually heavily regulated and may need further scrubbing if they exceed permissible limits. Higher levels of SOx emissions are usually fairly corrosive, too, and may require specialized metals or refractory-lined pipe for the hot flue gas from the oxidizer.

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