Experimental study and economic analysis of an absorption refrigeration system with new generator structure applied for pre-cooling in liquefied natural gas plant. (September 2021)

• Record Type: Journal Article
• Authors: Lu, Ding; Liu, Zijian; Bai, Yin; Sun, Shoujun; Gong, Maoqiong; Shen, Jun
• Is Part Of: International journal of refrigeration. Volume 129(2021)
• Page Start: 78
• Page End: 87
• Publication Date: 2021-09
• Subjects: Absorption refrigeration -- Liquefied natural gas -- Waste heat recovery -- Specific power consumption -- Experimental study -- Economic analysis; Froid à absorption -- Gaz naturel liquéfié -- Récupération de chaleur perdue -- Consommation électrique spécifique -- Étude expérimentale -- Analyse économique; Refrigeration and refrigerating machinery -- Periodicals; 621.56
• DOI: 10.1016/j.ijrefrig.2021.04.031
• Languages: English
• ISSNs: 0140-7007

Abstract

Highlights: COP of the absorption refrigeration prototype maintains between 0.29 and 0.35. Waste heat recovery ratio is improved by 150% when reboiler heating ratio is 0.37. Waste heat from both exhaust gas and jacket coolant is recovered in the generator. Specific power consumption of the modified LNG plant is reduced by 30%. Annual operating cost is reduced by 9.4% compared with conventional LNG plant. Abstract: In a variety of waste heat utilization technologies, absorption refrigeration can be driven by low-grade heat to provide cooling capacity, which is suitable for situations with both waste heat supply and refrigeration demand. In this paper, an ammonia-water absorption refrigeration prototype with a new generator structure is experimentally studied. Its economic analysis is carried out for pre-cooling in a liquefied natural gas plant. It is investigated that 1.8 kW cooling capacity at −10 °C is obtained, COP maintains between 0.29 and 0.35, and waste heat recovery ratio is improved by 150%. The proposed system is applied to a 30, 000 Nm 3 d −1 liquefied natural gas plant to replace the conventional compression refrigerator as the pre-cooling stage, and waste heat from exhaust gas and jacket coolant is recovered in the reboiler and stripping section, respectively, in order to provide cooling capacity for pre-cooling of both natural gas and refrigerant. Economic analysis shows that specific power consumption of the modified system is reduced by 30%, from 0.40 to 0.28 kWh Nm −3 . Consequently, the annual natural gas consumption and operating costs are reduced by 17.3% and 9.4%, respectively, and the payback period is 2.2 years compared to conventional systems with compressor-based pre-cooling stages.