Volume 33: CCUS Technologies for the Carbon Neutrality: Part I

Using the precipitation process of potassium carbonate with Ethanol + KOH solution to enhance the efficiency of CO2 mineralization storage in low permeability reservoirs Chengwei Wang, Yuliang Su, Wendong Wang, Lei Li, Yongmao Hao, Xincheng Guo



Carbon dioxide displacement and storage is the most feasible technology to realize carbon neutralization, and also the key technology to improve the recovery of tight reservoirs. CO2 capture and carbonization can be achieved by precipitation of potassium carbonate by using the “Ethanol + KOH” solution system. The reaction process in the solution system is affected by the ethanol concentration, resulting in different CO2 carbonization amounts with the change of ethanol concentration. At the same time, the potassium-based acid salt generated by precipitation can react with water to complete the regeneration of ethanol. In this paper, experimental means are used to study the CO2 capture efficiency of the “Ethanol + KOH” system, monitor the ethanol content in the solution in real time, and screen out the best ethanol concentration suitable for the formation temperature. Add KOH to the solution, use the ethanol regenerated in the solution after carbonization reaction to carbonize again, and determine the maximum CO2 capture of “ethanol + KOH”. Based on the high temperature and high pressure core displacement device, the CO2 burial experiment after the injection of “Ethanol + KOH” solution was carried out to clarify the change rule of CO2 burial under the action of “Ethanol + KOH” system in low permeability cores. The research results show that “96% ethanol+3g KOH” can effectively capture CO2, and each capture will produce 4.56g precipitation on average. At the same time, after the core is saturated with “96% ethanol+3gKOH” solution, CO2 is injected to generate sediment, and the core permeability decreases by about 15%. The research results of this paper prove that, compared with direct injection of CO2 into the formation, injection of this system into the formation in advance can accelerate the CO2 carbonization process, thus effectively improving the CO2 burial efficiency.

Keywords Carbon dioxide, Ethanol+KOH+CO2, potassium-based, CO2 Storage

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