Decarbonization method for producing liquefied natural gas from high-carbon natural gas

Abstract

The invention discloses a decarbonization method for producing liquefied natural gas from high-carbon natural gas. CO2 is removed from natural gas with a CO2 volume fraction of 10% or more to produceliquefied natural gas with a CO2 content of not more than 50 ppmv in the purified gas. Through the manner of rough decarburization and deep decarburization of a coarse absorption tower and a fine absorption tower, inputting a rich liquid of the fine absorption tower to the top of the coarse absorption tower, and high and low pressure flash evaporation or two-stage regeneration, the decarburizationefficiency is improved, and at the same time, process power consumption and regeneration natural gas consumption are reduced. A decarburization solvent consists of A and B two amines. The method reduces a circulation amount of a decarburization solution under the condition that purification indexes are met, and the benefits brought by reducing the circulation amount of the decarburization solution are as follows: saving purified natural gas used as fuel gas in a regeneration process, increasing treatment load of a decarburization apparatus, and reducing equipment investment and operating cost.

Description

technical field [0001] The invention belongs to the field of natural gas exploration and development ground construction engineering, and specifically relates to a decarbonization method for producing liquefied natural gas from high-carbon natural gas. Background technique [0002] Natural gas is a high-quality, efficient and clean low-carbon energy and chemical raw material, and its status as a resource is becoming increasingly prominent. To reduce CO 2 , dust and other pollutants, the global demand for natural gas continues to increase steadily, and China is growing rapidly. With the increasing demand for natural gas, some low-quality high-carbon natural gas (CO in raw natural gas 2 The volume fraction is not less than 10%) gas wells and gas fields are also under development and construction. Liquefied natural gas (LNG) is small in size, easy to transport, and flexible in storage and use in end-user networks, so a lot of natural gas will be used to produce LNG after ext...

AI Technical Summary

Problems solved by technology

MEA and DEA are primary and secondary amines, with strong alkalinity, and CO 2 The reaction speed is fast, and it has a good absorption speed. It is often used for CO 2 In the case where the partial pressure in the mixed gas is lower than 0.2MPa, but limited to the strong corrosiveness of MEA and DEA, the general use concentration is 15%~25% lower, the acid gas load is smaller, and a large amount of CO can be removed 2 A large amount of solution circulation is required, resulting in high regeneration heat consumption and power consumption

When CO 2 When the partial pressure is higher than 0.2MPa, various formula solvents based on MDEA are mostly used, and traditional formula solvents also have contradictions between decarburization purification and processing load

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