Thermodynamic analysis of the NGL plant in a sample gas refinery and problem solving by designing an absorption chiller

• Published in: Applied thermal engineering Vol. 159; p. 113963
• Main Authors: Tahmasebzadehbaie, Mohammad, Najafi Nobar, S., Derahaki, Masoud
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.08.2019; Elsevier BV
• Subjects: Absorption; Ammonia; Compression refrigeration cycle; Dew point; Gas absorption; Gas refinery; Gas turbine; Gas turbines; Modelling; Natural Gas Liquid (NGL); Problem solving; Refineries; Refrigeration; Thermal cycling; Thermodynamics; Water-ammonia absorption chiller; Compression refrigeration cycle; Natural Gas Liquid (NGL); Gas turbine; Water-ammonia absorption chiller; Gas refinery
• ISSN: 1359-4311; 1873-5606
• DOI: 10.1016/j.applthermaleng.2019.113963

•The dew point setting unit in a sample gas refinery is investigated in details.•Compression refrigeration cycle (CRC) turn off results in product reduction.•243.7 tons of propane and butane daily reduction is expected by turning off CRC.•Water-ammonia absorption chiller is designed as a standby option for CRC.•Absorption chiller cost is $5850 K and would be completely returned in 45 days. The power for chiller in dew point setting unit in the sample gas refinery is already being produced by a compression refrigeration cycle and a gas turbine. In case of gas turbine maintenance or failure, the unit would work without compression refrigeration cycle. Presence and absence of compression refrigeration cycle and its impacts on gas condensate production in the plant have been modeled in this study. Absence of compression refrigeration cycle would cause hourly reduction of 7.5 and 2.6 tons of propane and butane, respectively. Detailed modeling of the gas turbine has also been implemented in the next step and, then, compression refrigeration cycle has been coded for calculation of important parameter of the cycle. Finally, for improving the efficiency of the aforementioned unit, the water-ammonia absorption chiller has been introduced and designed for replacing the compression refrigeration cycle as a stand-by option. With the modeling of water-ammonia absorption chiller, the calculated fuel consumption of generator was found to be less than the available gas turbine, and the capital cost of this chiller is about $5,850,000. Consequently, it was discovered that in absence of compression refrigeration cycle for about 45 days, the cost of the absorption chiller would be completely returned.