Ice box used for natural gas liquefaction system

Abstract

The invention discloses a cold box for a natural gas liquefaction system, which comprises a precooling unit (1), a first separation tank (2), a second separation tank (3), a third separation tank (4) and a fourth separation tank (5); a first ejector (6) is connected to a passage between a feed gas outlet (1a) and a gas-liquid mixing inlet (2a) of the first separation tank; and a connecting channel is formed between a gas-liquid mixing inlet (3b) of the second separation tank and the feed gas outlet (1a), and is provided with a second ejector (7). The invention aims to provide a cold box for the natural gas liquefaction system, which has simple structure and small energy consumption and can process less than 300,000 cubic meters of natural gas daily.

Description

technical field [0001] The utility model belongs to the technical field of gas liquefaction systems, and in particular relates to a cold box for natural gas liquefaction systems. Background technique [0002] At present, the liquefaction cycles of natural gas liquefaction devices in the world are mainly: cascade refrigeration cycle, mixed refrigerant refrigeration cycle and expander refrigeration cycle. Most of these methods are suitable for base-type large-capacity liquefied natural gas, and the energy consumption is high in the case of processing less than 300,000 cubic meters of natural gas per day. In China, the expansion machine refrigeration cycle is often used for daily processing of natural gas below 300,000 cubic meters. The expander refrigeration cycle refers to the process of realizing the liquefaction of natural gas by using high-pressure refrigerant to expand adiabatically through the Claude cycle refrigeration of the turbo expander. Nitrogen, nitrogen-methane,...

AI Technical Summary

Problems solved by technology

[0005] 1. The refrigeration device has complex structure, large volume and complicated operation;

[0006] 2. When the refrigeration equipment is working, the equipment needs to run at high speed, resulting in poor system reliability;

[0007] 3. The primary liquefaction rate of the expansion machine refrigeration cycle is low, the theoretical value is between 8% and 12%, usually around 9%; therefore, the energy consumption of full liquefaction is relatively high

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