Abstract: Absorption refrigeration systems driven by low-temperature waste heat is one way to achieve “carbon neutrality.” Meanwhile, the keto-benzene dewaxing equipment needs a cooling capacity of 5 MW, with refrigeration temperature of -10 ℃ and -25 ℃. This paper researches the feasibility of dual-stage evaporation-ammonia hybrid compression-absorption refrigeration system (DSE-AHCARS) replacing the vapor compression refrigeration system for keto-benzene dewaxing process based on energy, exergy, economic, and environmental (4E) analysis. At the primary- and secondary-stage evaporation temperature of 0 and -23 ℃, respectively, the coefficient of performance (COP) reaches the maximum value of 0.85; however, COP-electricity reaches the minimum value of 8.1. When the secondary-stage refrigeration temperature is -23 ℃, CO₂ emission increases from 1150 t·a^-1 to 3600 t·a^-1, and life cycle climate performance increases from 3.29×10⁴ to 7.7×10⁴ t, with the primary-stage refrigeration temperature being -15-0 ℃, as well as matching three parameters to ensure the 4E compromising performance by the multi-objective optimization. To guarantee that the life cycle climate performance is less than 5.5×10⁴ t, the payback period is <2 a, and COP is >0.6 at the optimal operation ranges, such that the refrigeration temperature difference between primary stage and secondary stage is within 20 ℃. The power of DSE-AHCARS was reduced by 77% compared with the vapor-compression refrigeration system. Therefore, the DSE-AHCARS can reduce CO₂ emissions by about 6250 t·a^-1 and save 1.2×10⁵ t of CO₂ in the life cycle climate performance term. This result shows that the DSE-AHCARS can completely replace the vapor-compression refrigeration system.

Key words: Evaporation, Optimal design, Thermodynamic process, Multi-objective optimization, Ammonia hybrid refrigeration

摘要： Absorption refrigeration systems driven by low-temperature waste heat is one way to achieve “carbon neutrality.” Meanwhile, the keto-benzene dewaxing equipment needs a cooling capacity of 5 MW, with refrigeration temperature of -10 ℃ and -25 ℃. This paper researches the feasibility of dual-stage evaporation-ammonia hybrid compression-absorption refrigeration system (DSE-AHCARS) replacing the vapor compression refrigeration system for keto-benzene dewaxing process based on energy, exergy, economic, and environmental (4E) analysis. At the primary- and secondary-stage evaporation temperature of 0 and -23 ℃, respectively, the coefficient of performance (COP) reaches the maximum value of 0.85; however, COP-electricity reaches the minimum value of 8.1. When the secondary-stage refrigeration temperature is -23 ℃, CO₂ emission increases from 1150 t·a^-1 to 3600 t·a^-1, and life cycle climate performance increases from 3.29×10⁴ to 7.7×10⁴ t, with the primary-stage refrigeration temperature being -15-0 ℃, as well as matching three parameters to ensure the 4E compromising performance by the multi-objective optimization. To guarantee that the life cycle climate performance is less than 5.5×10⁴ t, the payback period is <2 a, and COP is >0.6 at the optimal operation ranges, such that the refrigeration temperature difference between primary stage and secondary stage is within 20 ℃. The power of DSE-AHCARS was reduced by 77% compared with the vapor-compression refrigeration system. Therefore, the DSE-AHCARS can reduce CO₂ emissions by about 6250 t·a^-1 and save 1.2×10⁵ t of CO₂ in the life cycle climate performance term. This result shows that the DSE-AHCARS can completely replace the vapor-compression refrigeration system.

关键词: Evaporation, Optimal design, Thermodynamic process, Multi-objective optimization, Ammonia hybrid refrigeration