Marine liquefied ethane vaporized gas re-liquefaction device

Abstract

The invention discloses a marine liquefied ethane vaporized gas re-liquefaction device. The marine liquefied ethane vaporized gas re-liquefaction device comprises an ethane vaporized gas loop and a three-stage compressed mixed refrigerant refrigeration loop. The ethane vaporized gas loop and the three-stage compressed mixed refrigerant refrigeration loop exchange heat through a heat exchanger so that ethane vaporized gas can be liquefied. The ethane vaporized gas loop comprises a BOG compressor. The three-stage compressed mixed refrigerant refrigeration loop comprises a low-pressure refrigeration compressor, a medium-pressure refrigeration compressor, a high-pressure refrigeration compressor, a low-pressure circulation throttle valve, a medium-pressure circulation throttle valve, a high-pressure circulation throttle valve, a medium-pressure gas-liquid separator and a high-pressure gas-liquid separator. A condenser is mounted between the high-pressure circulation throttle valve and the high-pressure refrigeration compressor. A BOG throttle valve and a BOG gas-liquid separator are successively arranged behind the heat exchanger. By the adoption of the marine liquefied ethane vaporized gas re-liquefaction device, the ethane vaporized gas can be recovered and used, and the waste of ethane is avoided.

Description

technical field [0001] The invention relates to a boil-off gas reliquefaction device, in particular to a ship-used liquefied ethane boil-off gas reliquefaction device. Background technique [0002] Ethane cracking is an important raw material for the production of ethylene, and the ethylene industry is the leader of the petrochemical industry and a symbol to measure the scale and development of a country's petrochemical industry. Under normal pressure, the equal weight of liquefied ethane is 1 / 435 of gaseous ethane. Therefore, in the maritime trade of ethane, ethane is usually liquefied and transported by cryogenic storage tanks and special liquefied gas ships. In order to maintain the temperature conditions of cryogenic liquid cargo in liquefied gas ships, the hull and storage tanks must have good heat insulation performance. However, due to the huge temperature difference between inside and outside, no matter how good the heat insulation measures are, it is inevitable tha...

AI Technical Summary

Problems solved by technology

However, due to the huge temperature difference between the inside and outside, no matter how good the heat insulation measures are, it is inevitable that external heat will leak into the cargo tank. In addition, the sloshing during the ship will also generate heat, which in turn will generate boil-off gas (BOG)

The generation of boil-off gas will increase the pressure of the cargo tank, and excessive pressure is not good for navigation safety, so certain measures must be taken to deal with BOG

[0003] Some liquefied gas ships are directly emptied or flared, which is not environmentally friendly and wastes energy, causing great economic losses

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