Natural gas liquefaction system with combination of auto-cascade refrigeration system and pulse tube refrigerator

Abstract

The invention relates to a natural gas liquefaction system with combination of an auto-cascade refrigeration system and a pulse tube refrigerator. A gas source output end is sequentially connected with a first-stage heat exchanger, a second-stage heat exchanger and a third-stage heat exchanger in an auto-cascade refrigeration cycle through a pressure stabilizing valve and a flow adjusting valve, so that heat exchange is carried out between a gas source and a mixed refrigerant in the first-stage, second-stage and third-stage heat exchangers for first-time cooling, second-time cooling and second-time cooling; the gaseous state natural gas output end of the third-stage heat exchanger is connected with an evaporator, so that heat exchange is carried out between the gaseous state natural gas and the refrigerant in the evaporator for fourth-time cooling. The gaseous state natural gas output end of the evaporator is wound around a cold head of the pulse tube refrigerator in a natural gas condensation box, so that heat exchange is carried out between the gaseous state natural gas and the working medium helium in the cold head in the pulse tube refrigerator in the natural gas condensation box, and the gaseous state natural gas is condensed into liquefied natural gas. The pipe output end wound around the cold head of the pulse tube refrigerator is connected with a storage device through a restricting element, so that the liquefied natural gas is depressurized after flowing through the restricting element and then flows into the storage device to be stored.

Description

technical field [0001] The invention relates to a low-temperature liquefied gas system, in particular to a natural gas liquefaction system combining an automatic cascade refrigeration system with a pulse tube refrigerator. Background technique [0002] As a clean energy, natural gas is the energy with the fastest growing consumption in the 21st century, and it will account for an increasing proportion of primary energy. Compared with coal and oil, natural gas is more environmentally friendly and cleaner, and at the same calorific value, natural gas is more affordable and economical. my country is a vast country, but the uneven distribution of resources and the imbalance of economic development are very serious. The resource-rich provinces in the west are relatively backward in economy and low in energy consumption; while the economically developed areas in the east lack energy. So in our country how to allocate and transport energy reasonably is very important. Urban gas...

AI Technical Summary

Problems solved by technology

The cascade liquefaction method has the disadvantages of many units, complicated process, many auxiliary equipment, and complicated pipeline and control system; the liquefaction method of mixed refrigerant has the disadvantages of high energy consumption and difficulty in the reasonable proportioning of mixed refrigerant; The liquefaction method of the machine has the disadvantages of low liquefaction rate, low reflux pressure, large heat exchange area, and is not suitable for miniaturization

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