excess of formaldehyde - air treatment 1

[misterd]

What is the best way to reduce (treat) emissions of formaldehyde coming for pulp processing? would it be enough to use a scrubber or go for some adsorbent?

 

Since formaldehyde has such a low molecular weight it generally does not absorb well onto things like carbon. Your best bet is a scrubber due to its high solubility or if possible incinerate it in a boiler or other similar unit. If srubbing is the chosen alternative the treatment the wastewater is easily handled aerobically but emissions from the treatment system need to be included in any permitting that will need to take place

 

[HARVL]

FORMALDEHYDE WILL REACT WITH NAOH. HOW MUCH HYDROGEN CAN BE EVOLVED. IF A SCRUBBER HAS Ph 11.5 AND THE HCHO CONC IS 0-1% AND THE NaOH/WATER IS 180 DEG f. WHAT AMOUNT OF HCHO WILL FORM HYDROGEN?

 

[HARVL]

i'M DEALING WITH A SMALL STREAM OF HCHO VAPORS ~250 LBS/DAY AND PLAN ON USING A CAUSTIC SCRUBBER. THE NAOH WILL REACT USING THE CANNIZARO REACTION AT LOWER TEMPS. THIS IS THE FORMATE ROUTE. THE OTHER ROUTE IS THE FORMOSE ROUTE. I'M DESIGNING IT NOW WITH THE CONCERN OF HYDROGEN FORMATION.

 

[PeterAB]

Scrubbing formaldehyde vapors with caustic is not always effective. Don't assume the Cannizaro reaction will happen automatically. I would recommend some test work first.

 

[vintage70]

Have you evaluated a pure water stream with packing without NaOH? You will need more height and more water, and generate a wastewater, but no H generation.

 

[gacguy]

There are carbons that are impregnated that will remove formaldehyde. What is the concentration and flow rate?

 

I strongly recommend the use of biofilter to remove formaldehyde from the air.This type of compound must be biodegraded by microorganisms, such it does in biological reactors or wastewater treatment plants

 

[vintage70]

VC
Be careful air stream concentration may be at toxic level.
If not biofilter is a good recommendation.

 

[atiaran]

I agree on the biofilter as an option (use an in-vessel, not open bed - it takes up less space). It will effectively treat the formaldehyde without the chemical costs, but make sure that any particulate coming off your process is dealt with prior to entering the biofilter to prevent clogging.