Low-temperature thermal performance of propane condenser for recovering LNG cryogenic energy

Key words:  natural gas  gasification  supercritical fluid  heat transfer  optimization design

Abstract:

Using propane to recover LNG cold energy is an effective way to avoid the problem of heat transfer with large temperature difference. The heat transfer between supercritical LNG and propane in the condenser was theoretically investigated, which is significant for the utilization of LNG cold energy. According to the propane state, LNG-propane heat transfer area can be divided into overheating region, two-phase region and sub-cooling liquid region. By means of parameter analysis method, the effects of some main parameters (propane inlet temperature, condenser size, propane flow rate) on the overall heat transfer performance of condenser were discussed. The results show that properly increasing LNG mass flow rate and decreasing channel width are beneficial to the recovery of LNG cold energy, while the effect of inlet temperature of propane gas on the recovery of LNG cold energy turns out to be little. The approaches that can improve the condenser effectiveness include determining the optimal propane inlet temperature, properly decreasing the propane mass flow rate and decreasing the width of propane-side channel.