How to make methane compressor from bicycle pump?

Methane (biogas) is a byproduct of a number of green alternatives such as a compost heap. This methane can be captured and processed usefully in small volumes. However it must be compressed to some level that will produce a controlled flow, let's say 14-20 pounds per square inch. In fact the methane could be captured and stored in a bicycle inner tube for later processing. Anybody got any thoughts on how a bicycle or small aquarium pump could be modified to compress small quantities of methane?

tomohern3 years ago
This link specifically deals with reclaiming CO2 while fermenting beer to use in force carbonating the final product in the keg, but the same method could be used to pressurize methane.
egbertfitzwilly (author)  tomohern3 years ago
You are exactly correct, this is precisely the solution I was looking for. Thank you for taking the time to respond and point this out for me.
lemonie4 years ago
The bicycle inner tube is too small, methane doesn't compress well and is better stored at low pressure in large tanks. What is your source of methane ? Diaphragm pumps can work well, but not the aquarium kind. L
egbertfitzwilly (author)  lemonie4 years ago
A few liters captured from a compost heap, septic tank or MFC array. Ideally the methane could be captured, fully combusted with the exhaust bubbled through an algae tank for a complete backyard CO2 scrub.
If you're serious about this research digesters
That might be a good starting point.

egbertfitzwilly (author)  lemonie3 years ago
Yeah, those are the cornerstone technology. Of course an MFC is just an anaerobic digester with some carbon electrodes. So algae could be flocculated out, fed into the anaerobic digester, tapped for a tiny bit of power, decomposed to methane and captured. If it is then compressed it can be used to heat water for steam with the exhaust captured and routed back through the algae tanks for CO2 scrub before being released.
I am working on a startup that is engaged in very similar recombinations of these technologies.. Photobioreactor, A.D. We are also working on how to safely compress methane at fairly low Psi (not liquefaction). One problem we are running into is the presence of O2 evolved by algae. This gas if mixed with methane and then compressed could be really messy. Although we think we have figured a way to get rid of the O2.
egbertfitzwilly (author)  Jdouenias23 days ago

How's your startup going? I may be interested....

First of all, one must have a completely sealed vacuum system. The inner tube must be new and have no other gas or air in it "new" When collecting the gas all other gases and elements must be exhausted. After collecting it one could use a diaphragm pump "Vacuum Pump" to compress it in a vacuum tight container or tank. Working with methane is like working with freaon. One needs to remove all air from a tank and replace it with methane and use a high cfm vacuum pump to compress it. If the pump is hooked to a ready supply of methane and it pumps the gas from the producing tank to the holding tank it can be set to hold a certain pressure like 20psi at all times. This will help in the process of burning like a propane tank will. Propane pressures off its boiling point temp. Methane needs the pump to make the same pressures.


Get More Out of Instructables

Already have an Account?


PDF Downloads
As a Pro member, you will gain access to download any Instructable in the PDF format. You also have the ability to customize your PDF download.

Upgrade to Pro today!