A method and system for producing carbon dioxide from coal-to-methanol

Abstract

The invention provides a coal-to-methane produced carbon dioxide immobilizing method. The coal-to-methane produced carbon dioxide immobilizing method comprises the following steps of S1, preprocessingcoal-to-methane produced carbon dioxide gas to obtain liquid carbon dioxide; S2, supplying the liquid carbon dioxide to microalgae; S3, absorbing the carbon dioxide through the microalgae. The invention meanwhile provides a coal-to-methane produced carbon dioxide immobilizing system. The coal-to-methane produced carbon dioxide immobilizing system comprises a carbon dioxide preprocessing system, acarbon dioxide supply system connected with the carbon dioxide preprocessing system, and a carbon dioxide absorbing system connected with the carbon dioxide supply system. The coal-to-methane produced carbon dioxide immobilizing method and system is particularly applicable to immobilizing carbon dioxide in gas with a concentration of carbon dioxide higher than 60%, and is low in energy consumption, high in carbon immobilization rate and free from in situ carbon immobilization; on the basis of ensuring no reduction of growth amount of the microalgae, the coal-to-methane produced carbon dioxideimmobilizing method and system achieves a carbon immobilization rate of 95-100% of closed type raceway pond microalgae and 65-70% of open type raceway pond microalgae.

Description

technical field [0001] The invention relates to a method and a system for producing carbon dioxide by fixing coal-to-methanol, in particular to a method and a system for using microalgae to fix the carbon dioxide produced by coal-to-methanol, and belongs to the field of environmental protection. Background technique [0002] my country has more coal and less oil, and both oil and olefins are dependent on imports. In order to solve this problem, the country actively develops the strategy of "replacing oil with coal", that is, coal is used as raw material to prepare methanol, and then olefins such as ethylene and propylene are produced through methanol. In the process of producing methanol from coal, a large amount of CO will be produced 2 , CO 2 Large production leads to climate change and increase in extreme weather, so cost-effective use of CO produced in coal-to-methanol process 2 Become the current focus of attention. [0003] in CO 2 Among many capture and utilizati...

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Problems solved by technology

[0005] However, at present, coal-to-methanol microalgae can fix CO 2 There are also the following main problems: one is the high concentration of CO 2 In the use of microalgae cultivation, compared with the use of low concentration, its volatilization and dissipation are larger; second, in the process of large-scale microalgae cultivation, since the raceway pond is often used for cultivation, in order to improve the microalgae to fix CO 2 efficiency, it is necessary to increase the CO 2 gas supply, however the shallow pool effect will increase the dissipation, resulting in CO 2 The utilization efficiency is reduced; the third is that the microalgae absorb CO 2 After that, the pH value of the culture system will change significantly, which will affect the growth environment of microalgae, and then affect the absorption of carbon dioxide by microalgae. Therefore, it is necessary to take an effective way to control the fluctuation range of pH value in the optimal range of microalgae growth.

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