Energy Efficiency Analysis of Postcombustion Hydrate-Based CO₂ Capture with Tetrahydrofuran and Tetra-n-butylammonium Bromide

Abstract

Hydrate-based gas separation (HBGS) is a novel carbon dioxide capture technology, which helps in the alleviation of the human-induced global warming crisis. However, hydrate formation for flue gases with relatively low CO2 concentration requires higher pressures or lower temperatures. The addition of thermodynamic and kinetic promoters seems to be the most efficient way of moderating the hydrate formation condition. In this research, a two-stage hydrate-based CO2 capture process was proposed and then simulated in Aspen HYSYS software to investigate the effect of two commonly used promoters tetrahydrofuran (THF) and tetra-n-butylammonium bromide (TBAB). These two promoters were then compared in terms of energy consumption, exergy loss, and environmental perspective. Sensitivity analysis was also carried out to study the effect of the split fraction of CO2. Results show that the energy consumed in the compression process is much more significant than that in the refrigeration process and the pumping process. Increasing the THF concentration from 1 to 3 mol % leads to a decrease of around 10% in the total electrical power consumption at the same formation condition. TBAB is recommended as an appropriate promoter compared with THF, considering the captured CO2 concentration, the flow rate of CO2, and effects on the environment. Exergy analysis results indicate that a considerable process exergy loss is caused by the clean gas outflows. In the sensitivity analysis, the split fraction of CO2 has a great impact on the concentration of the captured target gas and energy consumption per unit. Energy consumption results, exergy analysis, and sensitivity analysis in this study are of great value for research and development of HBGS technology for CO2 emission reduction.

Hydrate-Based Mild Separation of Lean-CH4/CO2 Binary Gas at Constant Pressure

“…However, the weakly selective gas can also form hydrates, resulting in the lower selectivity of hydrate-based gas separation (HBGS) . In addition, HBGS requires separation operations at higher pressures, while some studies , have indicated that the compression energy consumption accounts for more than 50% of the total technological energy. Therefore, more in-depth research is needed to improve the mild experimental condition and separation selectivity.…”

Insights into the Control Mechanism of Heat Transfer on Methane Hydrate Dissociation via Depressurization and Wellbore Heating

“…Thus, with the rapid increase of global energy demand, NGH is considered to be a new and potential energy on account of its enormous energy reserves . At present, various innovative technologies related to NGH have been developed for industrial applications, such as water desalination, energy storage and transportation, , gas separations, , and CO 2 capture and storage …”

“…6 At present, various innovative technologies related to NGH have been developed for industrial applications, such as water desalination, 7 energy storage and transportation, 8,9 gas separations, 2,10 and CO 2 capture and storage. 11 To realize the commercial extraction of natural gas from hydrate deposits in the future, a variety of exploitation methods have been proposed. The depressurization method, 12 in which the reservoir pressure is reduced below the hydrate equilibrium pressure, is generally acclaimed as the most effective one because of its simple technical requirements and high energy efficiency.…”

Hybrid Hydrate-Membrane Post-combustion CO2 Capture: A Conceptual Process Design and Analyses

“…Recently, Xie et al evaluated the effect of hydrate promoters on the energy consumption in the hydrate-based CO 2 capture process. In their recent study, they implied that energy consumption for the hydrate-based CO 2 capture process is higher than energy consumption for the MEA-based absorption process . In the processes designed by Tajima et al and Xie et al for post-combustion CO 2 capture, it was assumed that CO 2 recovery for each hydrate formation stage is 0.95, while the experimental studies show that actual CO 2 recovery for a single hydrate formation stage is much lower than 0.95.…”

“…In their recent study, they implied that energy consumption for the hydrate-based CO 2 capture process is higher than energy consumption for the MEAbased absorption process. 17 In the processes designed by Tajima et al 15 and Xie et al 16 for post-combustion CO 2 capture, it was assumed that CO 2 recovery for each hydrate formation stage is 0.95, while the experimental studies show that actual CO 2 recovery for a single hydrate formation stage is much lower than 0.95. Accordingly, the standalone hydrate formation CO 2 capture process to meet the CO 2 capture plants criteria (at least 90% of CO 2 captured with purity more than 95 mol %) is not sufficient.…”