Shell side condensation heat transfer characteristics of ethane/propane mixtures

Vertical helically baffled shell-and-tube heat exchangers (HBHXs) have been used as condensers in pre-cooling process of liquefied natural gas (LNG) plants, in which mixed refrigerants mainly containing ethane and propane should be condensed. In the present study, the heat transfer coefficients of ethane/propane mixtures in the shell side of a vertical HBHX test sample were tested, and the conditions cover ethane mass fraction of 13-50%, mass flux of 30-50 kg/m(2).s, heat flux of 3.0-7.0 kW/m(2), and vapor quality from 0.2 to superheated. The research results indicate that, distinct from the pure propane, the maximum heat transfer coefficient of ethane/propane mixture occurs at vapor quality around 0.8; the variation of heat transfer coefficient with the increase of vapor quality at low ethane mass fraction is more obvious than that at high ethane mass fraction due to stronger vapor shear effect; the heat transfer coefficient decreases dramatically with the increase of ethane mass fraction at high vapor quality, and it keeps almost constant at low vapor quality. A correlation for heat transfer coefficient was developed, and it agrees with 95% of experimental data within a deviation of +/- 25%.

Automated summary

The study investigated the heat transfer coefficients of ethane/propane mixtures in a vertical HBHX test sample, finding that the maximum heat transfer coefficient occurs at a vapor quality of around 0.8, and the variation of heat transfer coefficient is different at low and high ethane mass fractions. Additionally, a correlation for heat transfer coefficient was developed and showed good agreement with experimental data.