“1: CNG fueling pressures vary. A good fill is 3,000 to 3,400 psi. Many of the current CNG pumps don’t deliver a consistent psi fill rate.”
Are you sure about that? That doesn’t sound right. I was under the impression that methane/propane, the primary components of NG would liquefy at MUCH lower pressures than that, talking low hundreds of pounds. Once a liquid, no further compression is possible. You buy a new propane cylinder for a hand-held torch, you can hear liquid propane sloshing around. That type of stamped sheet-metal cylinder is no kind of 3000 lb affair, that’s for certain. Maybe methane has a higher vapor pressure but I doubt either of them (methane/propane) are in the thousands of lbs. I will check.
Check out the following post on CNGchat.com. Its one of the sources I’ve been using while looking at buying a CNG bi-fuel truck. The tanks I’ve seen used are aluminum wrapped in carbon fiber. These are high pressure and are expensive tanks. The following is a comment on the testing tanks experience.
http://cngchat.com/forum/showthread.php?t=845
The pressures I referenced were for pump fill pressures. Depending on the repair and upkeep of the pump the filling pressure may be lower than the 3000 psi + needed for a good “full” fill.