Coal-mine-goaf-based carbon dioxide underground sealing method and system

Abstract

The invention discloses a coal-mine-goaf-based carbon dioxide underground sealing method, belonging to the field of carbon dioxide emission reduction. The method comprises the following steps: injecting a CO2 exhaust-air mixture into a microalgae culture unit as a CO2 source, injecting the algae-containing water solution into an underground sealed space which is formed by reconstructing a coal mine goaf, separating microalgae from the water solution, and drawing the water solution out of the underground sealed space as a water source of the microalgae culture unit. The invention also discloses a coal-mine-goaf-based carbon dioxide underground sealing system. The underground sealed space reconstructed from the coal mine goaf is utilized to implement separation between the microalgae and water, thereby avoiding the problems of water body pollution and low separation cost in the traditional microalgae culture which needs to add the flocculant. The microalgae are fixed into the underground sealed space, thereby avoiding the problem of high cost due to demands for constructing the injection well and monitoring well in the traditional CCS technique, avoiding the problem of CO2 leakage, and further implementing low-cost safe reliable emission reduction of CO2.

Description

Technical field [0001] The invention patent belongs to the field of carbon dioxide emission reduction, and particularly relates to a method and a storage system for underground carbon dioxide storage based on coal mined areas. Background technique [0002] The greenhouse gas effect is currently a common concern of all mankind, and the global warming caused by it has already had a significant impact on the natural ecosystem. How to effectively control and reduce the emission of carbon dioxide and other greenhouse gases while the economy and society continue to develop is a serious problem faced by all countries in the world. At present, my country has publicly committed to CO by 2030 2 Emissions will no longer increase, and develop effective low-cost CO 2 Emission reduction technology has become an urgent need. [0003] my country's resource endowment conditions of "rich coal, less oil and less gas" determine that coal's main energy status in my country will not change for a long t...

AI Technical Summary

Problems solved by technology

However, the current CCS technology mainly has the following problems: First, some experts and scholars believe that CCS is only the CO 2 mothballed, and does not really achieve CO 2 reduction, not part of the CO 2 emission reduction; secondly, CO 2 The capture and storage of high-purity CO 2 , CO emissions from general coal chemical industry and power plants 2 The tail gas does not meet the requirements of direct storage, and additional CO is required 2 The purification system or the transformation of the power plant, such as the use of IGCC power generation or oxygen-enriched combustion technology, will greatly increase the CO 2 The cost of capture; again, CO 2 Underground storage has the potential for spillage and its safety is debated

At present, the main problem of microalgae carbon fixation technology is: the concentration of microalgae in the culture water (aqueous solution) used for microalgae cultivation is low (generally no more than 1wt%), and it is necessary to add a large amount of flocculant to separate microalgae from water, which will lead to The water body is polluted; the microalgae after precipitation and separation still contain a large amount of water (more than 95wt%), and the oil in it needs to be fully dried before being extracted. This series of processes will consume a lot of energy, and the energy consumed is far greater than Deriving energy from oils derived from microalgae is not economically viable

Images