Energy recoverable multi-stage dry sorbent CO2 capture process

Abstract

To reduce the energy required for CO 2 desorption, an energy exchangeable three-stage dry sorbent CO 2 capture process was designed and in the step of efficiency evaluation. The process is composed of three stages working at different sorptiondesorption temperatures to utilize the heat released at higher temperature absorption cycles for the regeneration of sorbent working at lower temperature cycles; low-, medium-and high-temperature stages. For this process three kinds of sorbents having different sorption-desorption temperatures were developed; amines supported on silica (low temperature), alkali-promoted MgO (medium temperature) and Li 4 SiO 4 (high temperature). Based on the kinetic properties of these three types of sorbents, several process models were simulated and it was found that dilute-dilute sorption-desorption process is the most efficient. According to the simulation, the thermal energy demand for the three-stage CO 2 capture process was 1.68 GJ/ton-CO 2 , which means about 60% of the thermal energy required for a single-stage dry sorbent process can be saved. To evaluate this concept, real facility which can treat 60 Nm 3 /hr exhaust gas was constructed and in the step of operation.

Thermal Decomposition of Biomineralized Calcium Carbonate: Correlation between the Thermal Behavior and Structural Characteristics of Avian Eggshell

“…CO 2 capture and storage by means of reversible solid–gas reactions have been studied as a potential method for reducing anthropogenic CO 2 and mitigating the greenhouse effect. − As such, alkaline and alkaline earth oxides and hydroxides have long been studied as potential CO 2 adsorbents. − Among other processes, CaO carbonation to form CaCO 3 and thermal decomposition of the CaCO 3 to reproduce CaO are the most extensively studied processes in terms of reaction kinetics, thermodynamics, and morphology: CaO (s) + CO 2 (g) ⇄ CaCO 3 (s). − Both the carbonation of CaO and the thermal decomposition of CaCO 3 are complex heterogeneous processes that are controlled by various physico-geometrical processes and reaction conditions including the partial pressure of CO 2 . The formation of surface product layers of CaCO 3 and CaO during carbonation and decomposition processes, respectively, is the most characteristic physico-geometrical factor controlling the heterogeneous kinetics, and it is generally seen for the reactions in solid–gas systems. − Because the diffusion of CO 2 through surface product layers is necessary for CO 2 intake and uptake, complete formation of CaCO 3 through the carbonation of CaO cannot be achieved in many cases due to the blocking of CO 2 diffusion by the surface product layer. , In addition, deterioration of the CO 2 absorption capacity is generally observed with repeated carbonation–decarbonation cycles .…”

Interfacial Interactions Govern the Mechanisms of CO2 Absorption and Desorption on A2CO3-Promoted MgO (A = Na, K, Rb, and Cs) Absorbents

“…Certain types of operations of CCS, including the aforementioned multiple-stage CO 2 absorption process, require all solid-state absorbents. 10 In the literature, there are a few examples of all solid-state absorbents of MgO, among which alkali carbonate (A 2 CO 3 ) promoters appear to be promising with the highest absorption capacity and kinetics. Studies using Na 2 CO 3 , K 2 CO 3 , and Cs 2 CO 3 as a promoter for MgO have been reported.…”

“…Energy- and cost-efficient operation of the process is also important, − for which Park et al proposed the multiple-stage CO 2 capture technology to be applied to the postcombustion process. In this technology, solid CO 2 absorbents operating at three different temperature ranges are to be used so that the waste heat from a higher temperature process can be used in the next lower temperature one . In this concept, the amine-impregnated absorbents can be used at low temperatures below 200 °C. − For the high-temperature (500 °C and higher) absorbents, CaO-based, lithium zirconate, and lithium silicate materials are considered. ,,− …”

“…However, although they significantly enhance the CO 2 absorption capacity of MgO, the nitrate promoters being in their molten state limits their applicability. Certain types of operations of CCS, including the aforementioned multiple-stage CO 2 absorption process, require all solid-state absorbents …”

“…10.1021/acs.jpcc.8b04895. Weight changes of A 2 CO 3 -MgO; MgO conversion plots; cyclic CO 2 absorption and desorption results; TG data; GC and MS data; IR spectra; thermal decomposition profiles;13 C solid-state MAS NMR spectra; XRD data;39 K and25 Mg solid-state MAS NMR spectra; XRD pattern and lattice parameter; EDS elemental mapping images (Figures S1−S13) (PDF) E-mail: ywkwon@skku.edu.…”