If propane vapor contains too much water vapor, cooling upon pressure reduction can lead to ice formation in valves and regulators, a situation that can cause operational problems for the fuel user. It has long been known that the addition of methanol to propane can reduce or eliminate fuel freezing problems. This document discusses the physical behavior of LP gas, methanol, and water, and methods of measuring the concentrations of water and methanol, as well as possible implications for fuel tank corrosion and fuel vaporization.
For a condensed look at the report’s findings, simply download the fact sheet here.
You can also download the guide for treating propane with methanol to prevent freezing of valves and regulators.