Offshore adaptability of the nitrogen expander liquefaction process with pre-cooling. (5th June 2019)

• Record Type: Journal Article
• Authors: Zhu, Jianlu; Zhang, Wei; Li, Yuxing; Wang, Wuchang; Liu, Yonghao
• Is Part Of: Applied thermal engineering. Volume 155(2019)
• Page Start: 373
• Page End: 385
• Publication Date: 2019-06-05
• Subjects: LNG process -- Pre-cooling -- Offshore adaptability -- Cold box -- Sloshing condition; Heat engineering -- Periodicals; Heating -- Equipment and supplies -- Periodicals; Periodicals; 621.40205
• DOI: 10.1016/j.applthermaleng.2019.04.016
• Languages: English
• ISSNs: 1359-4311

Abstract

Highlights: Precooling cycle can enhance the heat transfer curve of the nitrogen expander process. Surge and roll condition has no significant effect on the performance of PFHEs and expanders. Nitrogen expander liquefaction process with pre-cooling can be applied to medium-scale FLNG devices. Abstract: Nitrogen refrigerant has the advantages of simple preparation and safe operation, so it is suitable for use in offshore liquefied natural gas (LNG) production under sloshing condition. However, this process has a low efficiency and small processing scale, which limits its use in LNG Floating Production Storage and of Floating Unit (FLNG) devices. In order to solve this problem, the method of adding a pre-cooling process to the high-temperature region is generally adopted. In this study, firstly, different nitrogen expander liquefaction processes with pre-cooling were simulated. The pre-cooling refrigerants used in the simulation process were propane, carbon dioxide and mixed refrigerant, and the corresponding pre-cooling temperatures were −35 °C, −45 °C, and −85 °C, respectively. Subsequently, the performance of the three liquefaction processes with pre-cooling were analyzed and summarized. Finally, in order to verify the offshore adaptability of the pre-cooling nitrogen expander natural gas liquefaction process, a small liquefaction experimental device was built. The working performance of the plate-fin heat exchanger and expander under different working conditions was analyzed through the experiment of the surge and roll of the cold box. The results showed that the nitrogen expander liquefaction process with pre-cooling can be applied to medium-scale FLNG devices.