Biogas Treatment

Perhaps passing it over CaO or Calcium Oxide may consume CO2. H2S can be trapped in water to form H2SO4 or similar compound. look for these processes in details and also keep the desired temperature at which you can have best results.

Hello: An oil field company I used to work for treats oil products and wells with a biological scavenger. 1st we test for the quantity of the bacteria (via anerobic culture), once the quantity is determined and the source (takes up to 30 days for results - this is very simple processs) then we treat the the well (or source of the product) with the bacteriacide specific for anerobic bacteria. This will reduce the H2S. There are products to reduce or eliminate the C02, it is likely the bacteria producing the C02 is aerobic and can also be eliminated via bacteriacide.

Contact Nalco web site for types of chemicals they can provide. They are world-wide. I dont know how much of the bio-diesel you are producing, but you can access this company website to see if they would provide the testing (I used to be the lab person at a Nalco company) and the quantities they can provide. Then they would be able to recommend the quantity of bacteriacide. You can contact me for specifics if you need more info.

good morning

bio gas flow rate is 750 nm3/hr

composition: ch4 75% co2 25%

thanks for your advice for co2 removing from this stream.

Just burn the stuff! Pipiline natural gas is 90% methane; if you've got 75%, great! Landfill Cat gensets run on 50% methane, so will yours. A burner in a boiler won't even notice the lower btu's. The hydrogen sulphide shouldn't cause a problem, if it's under 1000 ppm. With my system I've been generating significant quantities of biogas for 3 years now (my wife will say much longer) so I know of what I speak.

H2S is toxic and so is CO or cabon mono-oxide. Avoid inhaling H2S so treatment or better process adoption is good idea. Not fully burnt organic gas form toxic carbon mono oxide, and inject more air or oxygen for burning the gas fully and use flushing system
for combustion gases.

Consortium service management group inc. ( CTUM.OB) out of the Ukrain has made major breakthrues in this and other subject matters. Jamesbg

There is a new technology that does just that. You can find it at www.mittonvalve.com

You should contact them for more information.

i am only your "basic midnight engineer"(no phd's in nutt'in); but it sounds like a problem that might be cured using the"membranes used for "fuek cells", since they are for specific elements, and probably work as well in reverse. also there is the new "ionic breeze's", "Ozone converter", you might get a filter/neutralizer from the folks who make that(public utility folks may give you ways to clean your gas production, similar to what they have to do for natural gas, before sending it through their pipelines!). or you could setup several specific element "lab litmus fiber/membrane filters" in long plastic tubes,from source to storagetank, a long "inline filter"?. i know they have been in use for labwork,for years, to remove all kinds of contaminents from air for their test projects and test critters air supplies, to keep their test results accurate,most of the time. hope you can find a simple,an cheaper, answer to your problem, chhukfin

Bubble through, or scrubbing with, a solution of Calcium Hydroxide will remove the Carbon Dioxide very effectively (Calcium Carbonate is formed and precipitates out of solution). Then, the Hydrogen Sulfide may be removed by bubbling through a solution of Ferric Hydroxide (Ferric Sulfide is formed and precipitates). This must be 2-stages, since the calcium hydroxide will react best at high pH, and the ferric hydroxide must be pH balanced at moderately acid conditions to be in solution. This is probably the simplest solution to your problem. This solution can be very simple, reasonably efficient and small scale, or very large, complex and highly-efficient. There will be a waste product to dispose of.

There are aerobic microbiological solutions to address the H2S, and since it is a much large molecule and polar (Methane is small and nonpolar) molecular seives and charge exclusion membranes maybe utilized. Care must be taken with the biological, since the bacteria are likely aerobic, and may utilize the methane also, producing more carbon dioxide.

This is nice solution and I will buy this idea. Looks like we have a real chemist here. Congratulations!

Sir,

For 15kg/day biogas production,how to excute this method(remove h2s ,Co2).what is the cost it will come?.If any low cost method for 15kg/day biogas production, Reply me my mail id: deepangr@gmail.com

Perhaps it is not necessary to remove CO2 as after burning more CO2 will get added and all is to be done is to take it to sufficient height and then release in air. H2S is nasty smelling gas and also toxic and for this passing the gas through water mixed with H2S absorbing chemicals looks ideal choice.

Nice tips.

For 15kg/day biogas production,how to excute this method.what is the cost it will come?.Reply me my mail id: deepangr@gmail.com

See info at woodgas.com

First of all, H2S is deadly in concentrations below what you can smell, and at higher concentrations your sense of smell is affected so that it seems not as high as it is. It is also very flammable.

Do you want to remove it for safety purposes, which when you remove it you must dispose of the waste?

I would suggest running the gas through a tower of molecular sieve to remove the H2S. You could also remove the CO2 in the same way. If you are going to burn it anyway, just select a molecular sieve that will remove the CO2 and then burn the bio gas with the H2S in it.

Hi,

you do not need to remove CO2 for a CHP or a genset.

For the H2S, the most simple method, but not as effective as the industrial processes would be to inject 5% O2 by volume in the biogas, right after it exits the digestor (determine your flow rate when you will start your generator with a corrosion resistant biogas meter). You can do so in a "well", buried in the ground and having an easy and sealed access. It will also remove moisture and precipitate H2S, which are both a no-no for any gas-ignition or compression engines. This method is used in low-cost AD systems for animal waste treatment.

If you want more information, look for Genesys GmBH or any company that make farm biodigestor.

Good luck,

Terry