GAS-COMPRESSION EQUATIONS EVALUATED.

Six equations of state have been compared with experimental compressibility factors to evaluate the accuracy and conditions for use of each equation. The equations are used to calculate gas-compressibility factors, which in turn are important parameters for density prediction for offshore gas-pipeline metering stations. The best equation gave an average absolute percent deviation of less than 0. 3%. Other well known equations gave deviations of 3-4%. The data base used contains more than 2,000 datapoints in the 10-300 bar absolute (bara) pressure range (145-4,350 psia).