Gas expansion natural gas pressurized liquefying technique with function of condensing and removing carbon dioxide (CO2)

Abstract

The invention relates to a gas expansion natural gas pressurized liquefying technique with a function of condensing and removing carbon dioxide (CO2), which comprises the steps of: precooling natural gas at a gaseous state in a precooler, continuously cooling the natural gas in a crystallizing device, condensing and separating solid dry ice while lowering the content of the CO2 to 0.5 percent, then pressurizing the natural gas in a low-temperature compressor, then introducing the natural gas in a liquefying device and liquefying the natural gas under higher pressure and then introducing the liquefied natural gas into a storage tank for storing. The cold capacity needed by the liquefying process is supplied by an independent gas expansion refrigeration circulation. Compared with the prior art, the gas expansion natural gas pressurized liquefying technique has the advantages that: a CO2 pretreatment device occupying a large floor area in the conventional natural gas liquefying process can be saved, so that the investment cost for liquefying the natural gas on an offshore platform in high price can be greatly reduced. Meanwhile, the energy loss of the refrigeration circulation can be reduced when the natural gas is liquefied at a higher temperature.

Description

technical field [0001] The invention belongs to the field of chemical industry and low temperature technology, relates to the purification and liquefaction process of natural gas, is a liquefaction process for removing carbon dioxide at low temperature during the liquefaction process of natural gas, and especially relates to a desublimation desublimation process during the liquefaction process of gas expansion natural gas under pressure. Liquefaction process for carbon dioxide removal. 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 si...

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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