CNG pump compressor DIY home refueling

[ijames]

Vlad, you were looking for info on industrial high pressure pumps. Many years ago we used some Haskel pneumatic amplifier pumps to compress various gases for research. We got them cheap (or free), gov't surplus, since universities with gov't grants can get surplus before it goes to general auction. Anyway, we worked with two models, a single stage 10 cc stroke volume with 30:1 amplification and the same pump with a two stage driver and 60:1 amplification. These ran off compressed air with 150 psi max inlet pressure so the single stage was rated 5000 psi output and the two stage was rated 10000 psi (old memories here, could have been 7500 and 15000 psi). We pumped nitrogen, CO2, R12, R22, methane, methanol, water, and various other things, studying their solvation properties at high pressure (supercritical fluid chromatography and extraction). These pumps, or copies, are what most scuba systems used back then (1980's) to "boost" a 2200 psi compressor output for steel tanks to 3000 psi for aluminum diving tanks, since lots of scuba shops had 2200 psi compressors that were still good and the aluminum tanks were still on the new side so actual 3000 psi compressors were still rare. Lots of models are listed on ebay for browsing. Yes, any blowby is vented to atmosphere, but if you are getting any blowby you need to fix the pump. Very simple construction, piston ring(s) and two check valves so rebuilding was easy. I don't know what the maximum strokes per minute was on them but we were limited by the cfm of our compressor plus the back pressure as our test cell came up to pressure. I recall maybe 1 stroke per second at the start of a run? You'd have to do the math to see if that gives you enough volume per day, and of course you need an air compressor. Just a thought, you could build an engine driven setup with a small stationary ng engine that drives both your York ac compressor and an air compressor to drive the Haskel. Anyway, it's not much detail but www . haskel . com has plenty of info (I'm a newbie so can't post a url yet). Hope this helps some.

[teoman]

Vlad, you are probably long gone by now.

I am curious if you got anywhere with this?

[teoman]

I have been pondering about this lately. It seems that approximately ( cng neing 8.8kwh/m3 and diesel 10 kwh/liter) with whatever tanks vlad has, if the can use a dridge compressor to pump up his tanks to 20 bats or atmospheres then he will see some kind of improvement.

I am an avid scuba diver (have multipe times the financial investment in my diving than my driving). I have a 6 liter scooba tank (the one that would not bother me if i were lugging it from the house to the car, i also have 2,3,10,15,18,30 liter tanks).

Pumping that up with a fridge compressor to 30 bars would yield me 180 ml equivalent of dielsel. If a commute is very shor that makes perfect sense.

[teoman]

I also pay 1/6 the cost of casloline and 1/5 the cost of diesel for the cng.

My commute is only 50 km/ day .


If I were to get a vw polo which consumes 3.6L/100 km with traffic that comes to 5l/100km where I live.

So 2.5 liters of diesel of which i can get 0.18 liters almost free. The relative savings are not insignificant.