Novel two-stage rectification auto-cascade natural gas liquefaction system and control method thereof

Abstract

The invention discloses a novel two-stage rectification auto-cascade natural gas liquefaction system. According to the system, two-stage rectification is adopted to achieve two-stage separation of mixed refrigerant components, the proportion of low-boiling-point components in the mixed refrigerant entering an evaporator is increased, the evaporation pressure of the system is increased, the working pressure ratio of a compressor is reduced, and the system performance is improved. Meanwhile, the middle air supply technology is introduced into the novel system, high-pressure refrigerants of part of flow paths only need to be throttled to middle pressure, the throttling loss of the system is greatly reduced, and the performance of the system is further improved.

Description

technical field [0001] The invention belongs to the field of chemical equipment, and in particular relates to a novel two-stage rectification self-cascading natural gas liquefaction system and a control method thereof. Background technique [0002] At present, the self-cascading natural gas liquefaction system has been widely used and developed due to its advantages of low cost, simple mechanism, and low control difficulty. For self-cascade systems, how to improve the separation efficiency of high and low boiling point components of zeotropic refrigerants is a key factor to improve system performance. The more fully the refrigerant components are separated, the better the system performance will be. The traditional self-cascading refrigeration system generally uses a gas-liquid separator to separate the components of the mixed refrigerant. The working pressure is too high and the energy efficiency of the system is low. On the other hand, since the working pressure of the s...

AI Technical Summary

Problems solved by technology

However, this system essentially achieves only one refrigerant component separation, which is not effective for the component separation of multi-component mixed refrigerants commonly used in the field of natural gas liquefaction, and the system needs to throttle all high-pressure refrigerants to the lowest pressure , the throttling loss is large, and there is a huge potential for performance improvement

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