Assessment of the energy efficiency of liquid separation plants using the freeze-off method based on entropy production analysis

Objective. The objective of the study is to develop a methodology for assessing the energy efficiency of liquid separation plants using the freeze-off method based on entropy production analysis. Based on the developed methodology, assess the feasibility of using a preliminary cooling stage for the initial liquid product in cryoconcentrators based on the volumetric principle of operation.

Method. The study is based on the method of entropy analysis of thermodynamic cycles of refrigeration units. A theoretical calculation was performed using the developed methodology for cryoconcentrators equipped with and without a preliminary cooling stage for the initial liquid product.

Result. It was shown that the presence of a pre-cooling stage, which is based on machine-free cooling of the initial liquid product using the cold of the ice mass obtained in the apparatus, is expedient and allows for a significant reduction in the energy consumption of the cryoconcentrator. The results of calculating the specific energy consumption of the cryoconcentrator, which characterizes the energy consumption for the production of one liter of concentrate, depending on the presence of a preliminary cooling stage of the initial liquid product for refrigerants R404A, R410A, and R507, are presented.

Conclusion. The developed method for assessing the energy efficiency of liquid separation plants using the freeze-out method based on entropy production analysis can be useful not only for designing cryoconcentration devices, but also for other volumetric equipment operating under ice formation conditions, such as ice generators and cold accumulators.

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