Offshore natural gas liquefying system

Abstract

The invention provides an offshore natural gas liquefying system. The offshore natural gas liquefying system comprises a light hydrocarbon separation device, a mixed refrigerant precooling cycle, a precooling main low temperature heat exchanger, a mixed refrigerant copious cooling cycle, a first copious cooling main low temperature heat exchanger and a second copious cooling low temperature heat exchanger. The light hydrocarbon separation device comprises a demethanization tower. Overhead gas of the demethanization tower sequentially makes heat exchange contact with the precooling main low temperature heat exchanger, the first copious cooling main low temperature heat exchanger and the second copious cooling low temperature heat exchanger after passing through a demethanization tower coldbox and an expansion compressor and then enters an LNG flash tank after passing through a main throttling valve, and LNG and BOG can be separated by the LNG flash tank. The mixed refrigerant precooling cycle makes heat exchange contact with the precooling main low temperature heat exchanger. The mixed refrigerant copious cooling cycle makes heat exchange contact with the first copious cooling mainlow temperature heat exchanger and the second copious cooling low temperature heat exchanger. Energy consumption of the liquefying system can be reduced, system pressure is relived, and the propane leakage risk is reduced.

Description

technical field [0001] The invention relates to a FLNG (Floating Liquefied Natural Gas, also known as LNG-FPSO) system. Background technique [0002] Natural gas resources are widely distributed on land and oceans around the world. From land to ocean is an inevitable trend of oil and gas exploration and development in the world. FLNG (Floating Liquefied Natural Gas, also known as LNG-FPSO) is a new type of offshore device proposed by the marine engineering community in recent years, which integrates the production, storage and loading and unloading of liquefied natural gas. It has a short construction period and development risks for the exploitation of offshore gas fields. Small, easy to move and high security features. [0003] Offshore operations need to consider unfavorable factors such as typhoons, waves, and space constraints, making the floating natural gas liquefaction process more difficult than land. As the core technology of FLNG, the rationality of natural gas ...

AI Technical Summary

Problems solved by technology

[0007] In order to overcome the shortcomings of the existing floating natural gas liquefaction technology, such as low safety, poor adjustability, high energy consumption, and poor economy, the present invention proposes a natural gas liquefaction system, which can realize stable and efficient separation of light hydrocarbons under different sea areas and different gas conditions and liquefied natural gas production

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