Using Volume Translation in Equations of State For Improving Accuracy of Liquid Density Prediction

Liquid densities predicted by Peng-Robinson equation of state (PR EOS), six other volume translation methods and three liquid density correlations over a range of reduced temperatures (0.3 – 0.99) were compared with experimental liquid density data for 29 pure compounds. Overall 1519 experimental data points were studied. The compounds studied were n-alkanes (C1 – nC20), ethylene, propylene, hydrogen sulfide, nitrogen, ammonia, carbon dioxide, and carbon monoxide. These compounds are involved in natural gas products such as liquefied natural gas (LNG), natural gas liquids (NGL), and liquid petroleum gas (LPG).For each compound, the average absolute percent error for all methods were calculated and reported. Even though applying volume translated methods improvements the accuracy of EOS liquid density predictions considerably, the correlation still have higher accuracy.

Keywords:

volume translation , liquid density , equation of state , property predicting , natural gas , LNG , NGL , LPG