Process for hybrid carbon capture and mineralization

Abstract

The principal approaches to reducing the effects of global warming seek to slow the increase in atmospheric CO2 levels as a result of fossil fuel combustion for energy production and transportation. A process for hybrid carbon capture and mineralization are disclosed. The process utilizes both flue gas from (e.g., power plants) and reject brine from (e.g., desalination process). The process includes providing flue gas to react with an amine solution to produce carbamate; processing the carbamate in a reactor to regenerate amine and to produce a carbonate; treating reject brine to provide a ready-made brine for carbonation reaction; and processing the carbamate with salt from treating the brine to produce a carbonate.

Claims

1. A process for hybrid carbon capture and mineralization, the process comprising: providing flue gas to react with an amine solution to produce carbamate; processing the carbamate to regenerate amine and to produce carbonates; treating reject brine to provide ready-made brine for carbonation reaction; processing the carbamate with salt from treating reject brine to produce a carbonate; precipitation of a solid carbonate from a liquid phase; separating the solid carbonate from the amine solution; and washing the solid carbonate and drying the washed solid carbonate to produce the carbonate.

2. The process of claim 1 further comprising providing a makeup amine to make up any amine loss during the process.

3. The process of claim 1, wherein the carbonate comprises an alkaline-earth metal of Group #2 (Ca, Mg, Ba, Be, Sr, and Ra) and a carbonate ion.

4. The process of claim 3, wherein the carbonate is at least one of CaCO.sub.3, MgCO.sub.3, Na.sub.2CO.sub.3, and BaCO.sub.3.

5. The process of claim 1, wherein the carbonate comprises an alkali metal of Group #1 (Li, Na, K, Rb, Cs, and Fr) and a carbonate ion, and wherein of an entrainer is added.

6. The process of claim 5, wherein the entrainer is from an organic family including one of acetone, ethanol, methanol, and isopropanol.

7. The process of claim 1, wherein the carbonate comprises a transition metal (Pb, Fe, Cu, and Cd) and a carbonate ion.

8. A process for hybrid carbon capture and mineralization, the process comprising: providing flue gas to react with an amine solution to produce carbamate; processing the carbamate to regenerate amine and to produce carbonates; treating reject brine to provide ready-made brine for carbonation reaction; and processing the carbamate with salt from treating reject brine to produce a carbonate, wherein the carbonate comprises an alkali metal of Group #1 (Li, Na, K, Rb, Cs, and Fr) and a carbonate ion, and wherein an entrainer is added.

9. The process of claim 8, wherein the entrainer is from an organic family including one of acetone, ethanol, methanol, and isopropanol.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) The patent or application file contains at least one drawing executed in color. Copies of this patent or patent application publication with color drawing(s) will be provided by the office upon request and payment of the necessary fee.

(2) FIG. 1 shows a Novel Absorption-Mineralization Process Flow Diagram.

(3) FIG. 2 shows a Group #2 Reaction Mechanism.

(4) FIG. 3 shows Rich Amine Regeneration Mechanism.

(5) FIG. 4 shows Carbon Capture, Sequestration and Utilization Reaction Experimental Steps.

(6) FIG. 5 shows FT-IR spectra of CaCO.sub.3.

(7) FIG. 6 shows XRD spectra of CaCO.sup.3.

(8) FIG. 7 shows FT-IR spectra of BaCO.sub.3.

(9) FIG. 8 shows XRD spectra of BaCO.sub.3.

(10) FIG. 9 shows FT-IR spectra of MgCO.sub.3.

(11) FIG. 10 shows FT-IR spectra of Na.sub.2CO.sub.3.

(12) FIG. 11 shows XRD spectra of Na.sub.2CO.sub.3.

DETAILED DESCRIPTION

(13) The present disclosure provides a process for hybrid carbon capture and mineralization. The process utilizes two waste streams including flue gas from power plants and other suitable sources and reject brine from desalination plants and other suitable sources for mineralization process to produce carbonates (e.g., CaCO.sub.3, MgCO.sub.3, Na.sub.2CO.sub.3, BaCO.sub.3, the like, and suitable combinations thereof). The process treats both flue gas and reject brine in the same process to produce commercially-valuable products (i.e., carbonates). The process also includes a step of regenerating amine.

(14) The processas illustrated in FIG. 1includes the following steps according to an embodiment: during step (1), flue gas reacts with an amine solution to produce carbamate; a circulated amine solution along with a makeup amine (e.g., to make up any amine loss during the whole process) enters to react with flue gas; and the resulting rich amine solution is directed to a reactor to regenerate amine and to produce carbonates. During step (2), reject brine is treated to make ready the brine (i.e., salt source stream) for carbonation reaction. During step (3), the rich amine solution (i.e., carbamate) reacts with salt from the brine to produce carbonates and regenerates the rich amine solution; this step ends with precipitation of carbonates from the liquid phase. During step (4), the solid carbonates are separated from the amine solution; the solid carbonates are washed with amine solutions and dried to produce anhydride carbonates.

(15) The process for hybrid carbon capture and mineralization can treat both flue gas (which is otherwise released to the environment) and reject brine (which is otherwise disposed to the environment), thus benefiting the environment in both ways. Further, both waste streams are utilized by the present process to produce commercially valuable products of carbonates, which are commonly used in concrete, cement and other suitable building blocks and applications.

(16) The present process provides a number of advantages including, for example: 1) it provides an economical process for CO2 capture, sequestration and utilization; 2) it is scalable and it can be designed to fit small-, mid- or large-scale plants; 3) it can be adaptable to any suitable gas stream and/or any suitable brine source stream; 4) a variety of different and suitable amine solutions may be used in the process; 4) it can be easily adapted to any suitable current or new co-generation plant; 5) it can work with any suitable alkaline waste streams; 6) it can work for any suitable CO2 source stream; 7) it can work for any suitable brine source stream.

(17) The present process provides a number of desirable features related to CO2 capture, for example: 1) it chemically regenerates the rich amine solution to provide a lean amine solution to the process; 2) it does not require any thermal energy for amine regeneration; 3) it does not require a stripper column in CO2 capture process; 4) it does not require an anti-corrosion of CO2 capture plant; 5) it works well at nearly room temperature; and 6) it does not require an external alkaline source.

(18) Further, the present process for hybrid carbon capture and mineralization is economically favorable as the starting materials are two waste streams and the end products do not need further treatment with a lifelong market demand.

(19) It should be understood that various changes and modifications to the presently preferred embodiments described herein will be apparent to those skilled in the art. Such changes and modifications can be made without departing from the spirit and scope of the present subject matter and without diminishing its intended advantages. It is therefore intended that such changes and modifications be covered by the appended claims.

EXAMPLES

(20) The following non-limiting examples are experimental examples supporting one or more embodiments provided by the present disclosure.

Example 1. Reaction for Ca-, Mg- and Ba-salts

(21) FIG. 2 shows examples of Group #2 Reaction Mechanism.

(22) In a two-neck round bottom flask, 10 g of piperazine was added to 80 g of deionized water under continuous stirring, at room temperature. Upon complete dissolution of the amine, the pH, measured by pH-meter, was raised to 11-12. CO.sub.2 gas (purity 4N) was purged via rubber septum into the solution with a pressure of 1 bar and continuous stirring (600 rpm). The pH gradually dropped between 7-6. After approximately 15 minutes, the pH became stable and 10 g of CaCl.sub.2) (or MgCb, or BaCb) was added to the mixture.

(23) Immediately, the solution turned from clear to milky and a white fine precipitate started crushing out. After 30 minutes from the addition of the salt, the purging of CO.sub.2 was stopped. The solution was filtered under vacuum. The filtrate was washed with deionized water and left to dry in the oven overnight. The resulting white solid, with yields ranging from 20 to 90%, was characterized by FT-IR, SEM, XRD, and EDS. All the used characterization techniques confirmed the formation of carbonate.

Example 2. Reaction for Na-Salts (Group #1)

(24) In a two-neck round bottom flask, 10 g of piperazine was added to 80 g of deionized water under continuous stirring at room temperature. Upon complete dissolution of the amine, the pH, measured by pH-meter, raised to 11-12. CO.sub.2 gas (purity 4N) was purged via rubber septum into the solution with a pressure of 1 bar and continuous stirring (600 rpm). The pH gradually dropped between 7-6. After approximately 15 minutes, the pH became stable and 80 g of acetone was added to the mixture. Once the two liquids mixed completely, 10 g of NaCl was added.

(25) Slowly, the solution turned from clear to milky and a white fine precipitate started crushing out. After 3 minutes from the addition of the salt, the purging of CO.sub.2 was stopped. The solution was filtered under vacuum. The filtrate was washed with acetone and left to dry in the oven overnight. The resulting white solid was characterized by FT-IR, SEM, XRD, and EDS. All the used characterization techniques confirmed the formation of carbonate.

Example 3. Regeneration Reaction

(26) FIG. 3 shows an example of a Rich Amine Regeneration Mechanism.

(27) FIG. 4 shows an example of Carbon Capture, Sequestration and Utilization Reaction Experimental Steps.

(28) The spent solution obtained from the aforementioned reaction was added to a two-neck round bottom flask under continuous stirring. The initial pH was in the range of 5-6. The pH was adjusted up to a value of 11 with the addition of cone NaOH solution. In another embodiment, a makeup amine also can be used. At this point, CO.sub.2 gas (purity 4N) was purged via rubber septum into the solution with pressure of 1 bar and continuous stirring. The pH gradually dropped between 7-6.

(29) Slowly, the solution turned from clear to milky and a white fine precipitate started crushing out. After 30 minute the purging of CO.sub.2 was stopped. The solution was filtered under vacuum. The filtrate was washed with deionized water and left to dry in the oven overnight. The resulting white solid was characterized by FT-IR, SEM, and EDS. All the used characterization techniques confirmed the formation of carbonate arising from the unreacted salt already present in the spent solution.

(30) TABLE-US-00001 TABLE 1 Summary of tested salts, regenerated amine, and product yield. Regenerated Product Amine Solution Brine Feed Yield % Product (gm) (gm) CaCl.sub.2 93.25 CaCO.sub.3 8.41 87.93 MgCl.sub.2 31.62 MgCO.sub.3 2.8 89.43 BaCl.sub.2 69.34 BaCO.sub.3 7.92 82.84 NaCl 22.88 Na.sub.2CO.sub.3 4.15

Example 4. Product Characterization of CaCO.SUB.3

(31) FIG. 5 (top figure) shows FT-IR for the experimentally produced CaCO.sub.3 and (bottom figure) FT-IR from the literature reference for comparison.

(32) FIG. 6 shows the XRD for the experimentally produced CaCO.sub.3.

(33) The isolated solids have been preliminary characterized by Attenuated total reflection (ATR) FT-IR and X-ray powder diffraction (XRD).

(34) The FT-IR spectrum for CaCO.sub.3 matches with the literature, revealing a mineral morphology like calcite. The XRD analysis confirmed the presence of calcite and valerite (see FIGS. 5 and 6).

Example 5. Product Characterization of BaCO.SUB.3

(35) FIG. 7 (top figure) shows FT-IR for the experimentally produced BaO.sub.3 and (bottom figure) FT-IR from the literature reference for comparison.

(36) FIG. 8 shows the XRD for the experimentally produced BaCO.sub.3.

(37) The FT-IR spectrum for BaCO.sub.3 matches with the literature. The XRD analysis confirmed the presence of BaCO.sub.3 as whiterite (See FIGS. 7 and 8).

Example 6. Product Characterization of MgCO.SUB.3

(38) FIG. 9 (top figure) shows FT-IR for the experimentally produced MgCO.sub.3 and (bottom figure) shows the FT-IR from the literature reference for comparison.

(39) The FT-IR spectrum for MgCO.sub.3 matches with the literature. The XRD analysis did not match with any known morphology for MgCO.sub.3, however, the Energy-dispersive X-ray spectroscopy (SED) confirmed the presence of hydrated MgCO.sub.3.

Example 7. Product Characterization of Na.SUB.2.CO.SUB.3

(40) FIG. 10 (top figure) FT-IR for the experimentally produced Na.sub.2CO.sub.3 and (bottom figure) shows FT-IR from the literature reference for comparison.

(41) FIG. 11 shows the XRD for the experimentally produced Na.sub.2CO.sub.3.

(42) The FT-IR spectrum for Na.sub.2CO.sub.3 matches with the literature (FIG. 10). The XRD analysis confirmed the presence of Na.sub.2CO.sub.3, as natrite, together with the presence of NaCl, that can be removed by further washing the sample with water:acetone mix (FIG. 11).

Example 8. Proof of Concept

(43) Regarding outputs, the solid product is Carbonate, not bicarbonate or other product, as characterized by the XRD analysis as well as FT-IR, EDS and SEM. The FT-IR analysis is compared with literature and confirmed carbonate formation.

(44) The reaction yield is the amount of product obtained in a chemical reaction. For benchmark comparison, one can compare against the conventional/standard process:
Na.sub.2CO.sub.3(aq)+Ca.sup.2+ or Mg.sup.2++CaCO.sub.3 or MgCO.sub.3

(45) TABLE-US-00002 TABLE 2 Yield comparison Benchmark Yield from Product conventional recess Yield from Novel Process CaCO.sub.3 Average of 90% Calera Process 93.25%

Example 9. Scale-Up

(46) The proof of concept was conducted on a lab scale (100 ml reactor volume). Increasing the scale of such a process requires will require additional and gradual scaling up of the reactor volume, while increasing the maturity of the process as reflected in the below Table 3.

(47) TABLE-US-00003 TABLE 3 Scale-Up Criteria Scale Reactor Volume Location Timeline Small 100 ml-1000 ml ROG-Applied Chemistry Lab By 2020 Mid 5000 ml RDC- Applied Chemistry Lab By 2022 Large 1000 L To be decided To be decided

(48) For each level of scale, different parameters are be checked and optimized for scale adaptions including: reaction conditions (temperature, pressure, and rotation speed); reactant ratios; amine type and concentration; regenerated amine solution activity; filtration, washing and drying time and type; product yield, stability and quality; detailed techno-economics study (payback, ROI, NPV, breakthrough point, etc.); and frequent updates to the products market need and value.

(49) The versatile process for hybrid carbon capture and mineralization is an economical process for CO2 capture, sequestration, and utilization; scale-adapted and can be designed to fit small, mid and large-scale plants; can be adapted for different gas stream; can be adapted for any brine source stream; succeed using many amine solvents; can be easily adapted to a current and new co-generation plant, where CO.sub.2 source is available from (flue gas) and reject brine stream is coming from desalination plants; and can succeed in alkaline waste streams.