Cascade type natural gas pressurized liquefaction process with sublimation removal of CO2

Abstract

The invention relates to a cascade type natural gas pressurized liquefaction process with sublimation removal of CO2. Natural gas is kept at a gas state and precooled in a precooler, and is fed into a crystallizer and kept on cooling, so that solid dry ice can be separated out by sublimation and the CO2 content is reduced to 0.5%; and then, natural gas is fed into a cryogenic compressor for pressurization, fed into a liquefier for liquefaction under a high pressure, and fed into a storage tank for storage. The cold quantity required by a liquefaction process is provided by an independent two-stage cascade refrigerating cycle. Compared with the prior art, the process provided by the utility model not only dispenses with CO2 pretreatment equipment which occupies a large area in the conventional natural gas liquefaction process, but also simplifies the traditional three-stage cascade refrigerating cycle to two-stage refrigerating cycle, so as to greatly reduce the cost of investment for natural gas liquefaction on an offshore platform which has high manufacturing cost. Meanwhile, the natural gas liquefaction at a high temperature also reduces the energy consumption of the refrigerating cycle.

Description

technical field [0001] The invention relates to a purification and liquefaction process of natural gas, which is a liquefaction process for removing carbon dioxide at low temperature in the natural gas liquefaction process, in particular a liquefaction process for desublimation and removal of carbon dioxide in the cascade natural gas liquefaction process under pressure. It belongs to the field of chemical industry and low temperature technology. Background technique [0002] Exploration practice has proved that there are abundant oil and gas resources in many sedimentary basins in China's sea area, and the proven offshore natural gas reserves are about 1 / 3 of the national natural gas reserves. The development and utilization of offshore natural gas can not only provide a clean energy with high calorific value, but also reduce the dependence on oil resources, which has important environmental protection and energy strategic security significance. In order to facilitate the t...

AI Technical Summary

Problems solved by technology

However, the material of the cooler in this patent needs to be one of metal oxide, ceramics, single crystal or sapphire, which is too special and expensive to be popularized and applied; and the solid phase as the core of the patent is in the center of the container rather than on the wall Formed technology, it is difficult to realize in engineering practice

The patent number is 5819555, and the title is "Removal of CO from feed stream through gas-solid separation 2 A method” of the U.S. Patent, which proposes the related desublimation to remove CO 2 technology, but it does not involve the natural gas liquefaction process, and cannot guarantee that the natural gas will not precipitate solid CO in the subsequent liquefaction process 2

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