Condensation of hydrocarbon mixtures in coil-wound LNG heat exchangers. Tube-side heat transfer and pressure drop

摘要

Based on an extensive experimental program, with 250 data points, methods for calculation of local heat-transfer coefficients and frictional pressure drops for tube-side condensation of hydrocarbon mixtures in coil-wound liquefied natural gas (LNG) heat exchangers have been developed. The dimensions of the test exchanger correspond to those of the coil-wound main heat exchangers in base-load LNG plants. Measurements of pure and mixed hydrocarbons in single-phase and condensing two-phase flow, at pressure up to 40 bar and mass flux up to 400 kg/m(sup 2)s, have been carried out in order to develop these methods. Measurements of R22 have also been accomplished. The effects of mixtures have been studied and, as expected, a reduction in the heat-transfer coefficients compared to corresponding pure components has been observed. The measurements are compared to selected methods from the reference literature. The deviations between the correlations were large. Those correlations which showed the best agreement with the measurements were used as a basis for developing new methods. More complex models based on a theoretical approach are also suggested.