Ultralow-temperature auto-cascade refrigeration system for preparing liquid nitrogen temperature zone of which temperature lower than 180 degrees below zero

Abstract

The invention discloses an ultralow-temperature auto-cascade refrigeration system for preparing a liquid nitrogen temperature zone of which the temperature lower than 180 degrees below zero. The system is characterized in that a primary refrigeration unit and a secondary refrigeration unit both adopt multiple non-azeotropic components, the components are physically mixed into different multi-component mixed working media, condensation of the low-boiling-point working media is achieved through evaporation of the high-boiling-point working media, a step-by-step fractional condensation auto-cascade structure is obtained, and the primary refrigeration unit and the secondary refrigeration unit conduct cascade again through an intermediate heat exchanger to prepare the required ultralow temperature. The system achieves the technical effects that a primary compressor and a secondary compressor are adopted to drive the different multi-component mixed working media, the step-by-step fractionalcondensation is conducted, the auto-cascade of condensation of the low-boiling-point working media is achieved through evaporation of the high-boiling-point working media, and meanwhile the primary cascade and the secondary cascade is conducted again to obtain the temperature finally lower than 180 degrees below zero of the liquid nitrogen temperature zone; and the temperature lower than 180 degrees below zero prepared through the system belongs to the liquid nitrogen temperature zone, and the prepared temperature is obviously lower than that of all existing mechanical refrigeration auto-cascade refrigeration technologies on the market.

Description

technical field [0001] The invention relates to the technical field of natural cascading cryogenic refrigeration systems, in particular to an ultra-low temperature self-cascading refrigeration system used for producing a liquid nitrogen temperature region below -180°C. Background technique [0002] The preparation of ultra-low temperature is widely used in ultra-low temperature environment simulation, oil and gas capture, frozen storage, extraction and purification and other industries such as military aerospace, biomedicine, electronic chemical industry, metal processing, ocean fishing and other industries. [0003] The traditional self-cascading refrigeration system mainly includes compressors, condensers, gas-liquid separators, throttling devices, heat exchangers, throttling devices, and evaporators; Combination) is compressed by a compressor to form a high-temperature and high-pressure gas; condensed by a condenser to form a gas-liquid mixture; a gas-liquid separator sep...

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Problems solved by technology

[0005] For this reason, the present invention provides an ultra-low temperature self-cascading refrigeration system for producing liquid nitrogen below -180°C in order to solve the problem of poor refrigeration effect, poor economy and low energy efficiency in the existing low-temperature refrigeration system, which cannot achieve ideal The refrigeration effect cannot be lowered, and the urgent needs of various industries for specific ultra-low temperature environments cannot be met.

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