Experimental study on supercritical CO2 jet characteristics and coal breakage utilization in carbon capture, utilization and storage (CCUS) process

Abstract

In the framework of Global Warming strategies, the safe utilization of carbon dioxide (CO2) is an important component of the Carbon Capture, Utilization, and Storage (CCUS) process. In the analysis of the jetting process of supercritical CO2 (S-CO2), it is of paramount importance to accurately predict the temperature and pressure characteristics of the jetting zone and the structure of the Mach disc. This is crucial for enhancing the utilization of S-CO2 in coal breaking. In this study, an experimental platform featuring an exceptionally large pipeline, measuring 258 m in length and 233 mm in diameter, was first time employed to acquire data on coal-breaking characteristics in the jetting zone of S-CO2 and images depicting the development process of Mach discs. A model for accurate predict Mach discs were developed and applied to optimum jet distance. The experimental data suggested that the jetting zone comprises a significant amount of three-phase flow consisting of gas, liquid, and solid phases. Moreover, maintaining a sufficiently long duration of jetting pressure in the jetting zone is advantageous for coal-breaking utilization. The Mach disc prediction model was optimized based on the measured pressure data downstream of the Mach disc. The optimized predictive model relies on parameters representing the actual pressure ratio for the Mach disk position, as follows: 0.65 for diameter, 0.29 for boundary layer thickness, and 1.36 for Mach disk location. This model, derived from experimental measurements of S-CO2 jet flows, exhibits enhanced suitability for the quantitative prediction of CO2 Mach disk phenomena. The findings presented in this thesis add to our understanding the prediction of S-CO2 Mach Disk. These data support further CO2 development of the determination of the optimal jetting distance is crucial in jet utilization processes.