A system is provided for calculating the vapor pressure for a liquid whose composition is unknown. The liquid to be tested is passed through a gas/liquid separator at a substantially constant flow rate and at a predetermined temperature and pressure. The liquid being passed through separator evolves gas which is passed through a gas meter. The liquid passing from separator passes through a flow meter. The evolved gas is also coupled to a gas chromatograph for measurement of the gas composition. The measurement data is input to a processor for converging an initial assumed inlet oil composition, with the measured gas composition, gas flow rate, and liquid flow rate using representative constituent equilibrium data to derive the composition of the inlet liquid stream. The converged liquid composition data is then utilized for calculating the vapor pressure or vapor emissions of the liquid.
Patent Number: 5,499,531
Date Issued: March 19 1996