Pipeline gas differential pressure refrigeration liquefying device and technology by combining nitrogen to achieve expansion refrigeration

Abstract

The invention discloses a pipeline gas differential pressure refrigeration liquefying device by combining nitrogen to achieve expansion refrigeration. The device comprises a first purifying unit. The first purifying unit is sequentially connected with the first purifying unit, a first cold box and a first natural gas expansion machine through a natural gas inlet pipeline. The first natural gas expansion machine is sequentially connected with the first cold box and a natural gas booster compressor through a pipeline. The natural gas inlet pipeline is further sequentially connected with a second purifying unit, a second natural gas expansion machine, the first cold box, a second cold box, a first product valve and LNG. The natural gas inlet pipeline is further sequentially connected with the second purifying unit, the first cold box, the second cold box, a second product valve and LNG. A nitrogen pipeline is sequentially connected with a nitrogen booster compressor, a first air cooler, a first section of compressor, a second air cooler, a second section of compressor, a third air cooler, the first cold box, a nitrogen expansion machine and the second cold box; then, the nitrogen pipeline is connected with the first cold box and the nitrogen booster compressor through the second cold box, so that nitrogen circulating is achieved. The pipeline gas differential pressure refrigeration liquefying device by combining nitrogen to achieve expansion refrigeration has the advantage of being low in energy consumption.

Description

technical field [0001] The invention belongs to the technical field of natural gas liquefaction, and relates to a pipeline gas differential pressure refrigeration liquefaction device combined with nitrogen expansion refrigeration and a process. Background technique [0002] With the development of the economy, the demand for energy increases by 10% every year. Natural gas is a widely used clean fossil fuel and can reduce greenhouse gas emissions. The maximum pressure of natural gas transported by pipeline on land can reach 10MPa. However, high-pressure natural gas usually undergoes an irreversible throttling process at the city gate station to reduce the pressure to meet the needs of different applications. At the same time, due to the sudden drop in pressure and temperature of natural gas, it is easy to pose a threat to the safe operation of pressure regulating equipment and pipeline equipment. In order to avoid overcooling of the pressure regulating equipment and pipelin...

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Problems solved by technology

[0004] The purpose of the present invention is to provide a pipeline gas differential pressure refrigeration liquefaction device combined with nitrogen expansion refrigeration, which solves the existing process technology of effectively utilizing the existing pressure energy of pipeline gas, thereby processing natural gas into LNG with low energy consumption and high liquefaction rate question

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