Method for trapping and storing co2

Abstract

Method for trapping and storing CO2 mechanochemically, comprising the following steps: a) dissolving an amine or an amino acid in order to obtain a concentrated solution, of which the concentration of amine functions is at least 3M; b) bringing the resulting solution into contact with a CO2-containing gas; c) 1. bringing the concentrated solution obtained in step b) into contact, with stirring, with an oxide, a hydroxide, a silicate, an aluminate, a phosphate, a chloride or a sulfate of an alkaline-earth metal or with a material containing an oxide, a silicate, an aluminate, a phosphate, a chloride or a sulfate of an alkaline-earth metal, the energy used for the stirring being at least 2.5 W per gram of stirred sample; or 2. bringing the precipitate obtained in step b) into contact, with milling, with an oxide, a hydroxide, a silicate, an aluminate, a phosphate, a chloride or a sulfate of an alkaline-earth metal or with a material containing an oxide, a silicate, an aluminate, a phosphate, a chloride or a sulfate of an alkaline-earth metal, the energy used for the milling being at least 2.5 W per gram of milled sample; and d) washing the solid obtained.

Description

[0001] CO2 CAPTURE AND STORAGE PROCESS

[0002] The present invention relates to a new method for capturing and storing CO2.

[0003] The manufacture of hydraulic binders, and in particular cements, essentially consists of calcining a mixture of carefully selected and measured raw materials, also known as "raw material". The firing of this raw material produces an intermediate product, clinker, which, when ground with calcium sulfate and possible mineral additions, produces cement. The type of cement produced depends on the nature and proportions of the raw materials as well as the firing process. There are several types of cement: Portland cements (which represent the vast majority of cements produced in the world), aluminous cements (or calcium aluminate cements), natural quick-setting cements, sulfo-aluminous cements, sulfo-belitic cements and other intermediate varieties.

[0004] The most widely used cements are Portland cements. Portland cements are made from Portland clinker, obtained after clinkerization at a temperature of around 1450°C of a raw material rich in calcium carbonate in a kiln. The production of one tonne of Portland clinker is accompanied by the emission of significant quantities of CO2 (approximately 0.8 to 0.9 tonnes of CO2 per tonne of cement in the case of clinker).

[0005] However, in 2014, the quantity of cement sold worldwide was around 4.2 billion tonnes (source: Syndicat Français de l'Industrie Cimentière - SFIC). This figure, which is constantly increasing, has more than doubled in 15 years.

[0006] During the production of clinker, the main constituent of Portland cement, the release of CO2 is linked to:

[0007] - up to 40% for heating the cement kiln, grinding and transport;

[0008] - up to 60% to so-called chemical CO2, or decarbonation.

[0009] Decarbonation is a chemical reaction that occurs when limestone, the main raw material for Portland cement, is heated to high temperatures. The limestone is then transformed into quicklime and CO2 through the following chemical reaction: To reduce CO2 emissions linked to the production of Portland cement, several approaches have been considered so far:

[0010] - the adaptation or modernization of cement processes in order to maximize the efficiency of heat exchanges;

[0011] - the development of new “low carbon” binders such as sulfo-aluminous cements prepared from raw materials with less limestone and at a lower firing temperature, which allows a reduction in CO2 emissions of around 35%;

[0012] - or the (partial) substitution of clinker in cements by materials that limit CO2 emissions.

[0013] Carbon capture and storage technologies have also been developed to limit CO2 emissions from cement plants and coal-fired power plants. Unfortunately, these technologies have not reached the level of development required for large-scale application. Furthermore, these technologies are expensive.

[0014] International patent application WO-A-2019 / 115722 describes a method for both cleaning CO2-containing exhaust gases and producing additional cementitious material. The method described involves using recycled concrete fines comprising providing recycled concrete fines with dgo 1000 pm in stockpiles or a silo as a feedstock, rinsing the feedstock to provide carbonaceous material, removing the carbonaceous material and the cleaned exhaust gas, and deagglomerating the carbonaceous material to form the additional cementitious material, as well as using stockpiles or a silo containing a feedstock of recycled concrete fines with dgo 1000 pm for cleaning CO2-containing exhaust gases and simultaneously producing additional cementitious material.However, to be economically and industrially viable, this process requires that the waste be located close to the CO2 source. In addition, since the CO2 fixation reaction takes place on a solid matrix, the kinetics are slow and the yields in terms of CO2 content sequestered in the solid matrix are low.

[0015] At the date of the present invention, it therefore remains necessary to identify new processes for capturing and storing the CO2 contained in industrial exhaust gases, in particular in exhaust gases from cement production, the kinetics and efficiency of which make it possible to significantly reduce CC>2 emissions and an implementation which is industrially and economically viable.

[0016] Among the various techniques for capturing and storing CO2, the so-called “integrated absorption mineralization” (IAM) pathway has been the subject of numerous studies, such as those of Meishen Liu et al., “Integrated CO2 Capture, Conversion, and Storage To Produce Calcium Carbonate Using an Amine Looping Strategy”, Energy Fuels, 2019, 33, 1722-1733, and “Integrated CO2 Capture and Removal via Carbon Mineralization with Inherent Regeneration of Aqueous Solvents”, Energy Fuels, 2021, 35, 8051-8068.

[0017] This pathway can be summarized by the following reaction scheme: Then in which X denotes the CO2 sensor and M denotes a mineral, in particular a mineral rich in calcium or magnesium.

[0018] It mainly consists of capturing CO2 using a solvent and then bringing the solution thus obtained into contact with a mineral acceptor such as CaO or MgO in order to carbonate it and thus obtain an insoluble and stable carbonate.

[0019] Work on the IAM pathway has been the subject of numerous publications.

[0020] The CO2 absorbents mainly used so far have been industrial amines, in particular monoethanolamine (MEA), diethanolamine (DEA), N-methyldiethanolamine (MDEA), 2-amino-2methylpropanol (AMP), piperazine and 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU). However, in the IAM strategy, a crucial point for industrial development concerns the loss of the amine in the mineral carbonate matrix formed. Indeed, this sequestration induces a double economic penalty for a potential process: consumption of the absorbent during IAM cycles and necessary replenishment; and reduction of the market value of the carbonate formed.

[0021] Furthermore, the eco-toxicity of the industrial amines used greatly reduces the possibilities of using the carbonate finally formed. As a result, research has focused on the use of an alkaline amino acid salt, sodium glycinate (NaGly), to capture CO2, particularly due to its environmental safety.

[0022] Regardless of the CO2 absorbent used, the process implemented consists of a "one-pot" process in a closed system in which the mineral acceptor is suspended in a CO2 absorbent solution contained in a reactor under a constant atmosphere at pCO2 = 1 atm, the depression induced by the absorption of CO2 being compensated by the constant supply of gas containing CO2. Once the reaction is complete, solid (carbonate mineral acceptor) and liquid are separated by filtration, the solid is washed and the liquid phases are combined for reuse.

[0023] In this process, the carbonation of the mineral acceptor therefore takes place in a liquid medium, and a large quantity of water is therefore necessary for its implementation, which poses a difficulty, particularly from an environmental point of view. In addition, carbonation requires high temperatures (around 80°C), which therefore consumes energy and reduces the solubility of CO2 in the liquid phase. Finally, the reaction kinetics are low and the regeneration rate of the CO2 absorbent is not high enough, which calls into question the economic viability of the process.

[0024] It would therefore be interesting to identify new processes for implementing the "IAM" route with reaction kinetics and yields that are acceptable from an industrial point of view, and which would make it possible to limit the quantity of water used as well as sufficient regeneration of the CO2 absorbent used.

[0025] In “Integrated CO2 Capture and Removal via Carbon Mineralization with Inherent Regeneration of Aqueous Solvents”, Energy Fuels, 2021, 35, 8051-8068, authors Meishen Liu et al. study a CO2 capture process involving the formation of carbonates, in particular the “IAM” process, consisting of capturing a fraction of the CO2 contained in large excess in a reactor using a solvent (MEA, NaGly, NaOH, AMP or DBU) in the presence of a mineral acceptor such as CaO, CaSiOs and MgO in order to carbonate it and thus obtain an insoluble and stable carbonate (see “Introduction” and “Materials & methods”). The concentration of the tested amine solutions ranged from 0.5M up to 5M, but the authors report that the use of amine solutions (especially AMP and DBU) with a concentration higher than 1M inhibits (at least partially) carbon mineralization due to the formation of viscous, gel-like fluids.Using solutions with an amine concentration below 1 M requires the use of large quantities of water. In addition, only a (minor) fraction of the CO2 in the reservoir is thus mineralized.

[0026] However, a method for implementing the IAM route has now been found that significantly limits the amount of water required compared to the methods used to date. Furthermore, the reaction kinetics, yield and regeneration rate of the CO2 absorbent used are significantly higher than those used conventionally.

[0027] Thus, the subject of the present invention is a method for capturing and storing CO2 comprising the following steps: a) dissolving an amine or an amino acid in order to obtain a concentrated solution whose amine function concentration is at least 3M; b) bringing the solution thus obtained into contact with a gas containing CO2; c) 1. bringing the concentrated solution obtained in step b) into contact, while stirring, with an oxide, a hydroxide, a silicate, an aluminate, a phosphate, a chloride or a sulfate of an alkaline earth metal or a material containing an oxide, a silicate, an aluminate, a phosphate, a chloride or a sulfate of an alkaline earth metal, the energy used for stirring being at least 2.5 W per gram of the stirred sample; or

[0028] 2. bringing into contact, under grinding, the precipitate obtained in step b) with an oxide, a hydroxide, a silicate, an aluminate, a phosphate, a chloride or a sulfate of alkaline earth metal or a material containing an oxide, a silicate, an aluminate, a phosphate, a chloride or a sulfate of alkaline earth metal, the energy used for grinding being at least 2.5 W per gram of the ground sample; and d) washing the solid obtained.

[0029] The method according to the present invention therefore allows the use of a concentrated solution of amine or amino acid to capture the CO2, and the obtaining of a precipitate or a concentrated solution containing the CO2, and, consequently, the carrying out of the carbonation step of the alkaline earth metal oxide by dry means or in the presence of small quantities of water, which significantly limits the quantities of water required in comparison with the methods implemented up to now. Furthermore, the reaction kinetics, the yield and the regeneration rate of the CO2 absorbent used are significantly higher than for the methods conventionally used.

[0030] In the context of the present invention:

[0031] - “amino acid” means any amino acid known to those skilled in the art, in particular amino acids of the following general formula (I) or (II): in which

[0032] R represents a hydrogen atom, a Ci-Cs-alkyl group optionally substituted by at least one group chosen from hydroxyl, amino; -C(O)-OH; -S(O)2-OH; -C(O)-O-, M+; -S(O)2-Q-, M+;

[0033] M+ representing a cationic counterion such as alkali metal, alkaline earth metal, or ammonium; n is 0 or 1; as well as their optical isomers and their alkali salts;

[0034] - "proteinogenic amino acid" means any amino acid selected from alanine (Ala), arginine (Arg), asparagine (Asn), aspartate (Asp), cysteine ​​(Cys), glutamate (Glu), glutamine (Gin), glycine (Gly), histidine (His), isoleucine (Ile), leucine (Leu), methionine (Met), phenylalanine (Phe), proline (Pro), pyrrolysine (Pyl), selenocysteine ​​(Sec), serine (Ser), threonine (Thr), tryptophan (Trp), tyrosine (Tyr), valine (Val) and lysine (Lys) or one of its derivatives of formula (III) in which n is an integer equal to 1, 2, 3 or 5, as well as their optical isomers and their alkali metal salts; and - “amine” means any compound comprising at least one primary or secondary amine function. Preferably, “amine” denotes any compound comprising at least one primary amine type function;

[0035] - "alkaline salt" means any addition salt obtained with a mineral or organic base by the action of such a base in an organic or aqueous solvent such as an alcohol, a ketone, an ether or a chlorinated solvent. Examples of such salts include ammonium (NH ), calcium (Ca 2+ ), iron (II) (Fe 2+ ) or (III) (Fe 3+ ), magnesium (Mg 2+ ), potassium (K + ), sodium (Na + ) or lithium (Li + ). Preferably, the term “alkali salt” means a lithium, potassium or sodium salt;

[0036] - "concentrated solution" means any aqueous or organic solution, excluding suspensions, whose amine function concentration is at least 3M, preferably at least 4M, preferably at least 5M, more preferably at least 6M and most preferably at least 8M; and

[0037] - “mechanochemical pathway” means any pathway involving a chemical reaction induced by the absorption of mechanical or kinetic energy.

[0038] Step a) of the process according to the present invention therefore corresponds to a step of dissolving an amine or an amino acid in an organic solution.

[0039] Preferably, step a) of the process according to the present invention is carried out under the following conditions, taken alone or in combination: the amine is chosen as being ethylenediamine (EDA), diethylenetriamine (DETA), monoethanolamine (MEA), diethanolamine (DEA), N-methyldiethanolamine (MDEA), 2-amino-2methylpropanol (AMP), piperazine, 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), cadaverine, putrescine, spermidine or spermine. More preferably, the amine is selected from ethylenediamine (EDA), diethylenetriamine (DETA), monoethanolamine (MEA), diethanolamine (DEA), N-methyldiethanolamine (MDEA), 2-amino-2methylpropanol (AMP), piperazine and 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU). Most preferably, the amine is selected from monoethanolamine (MEA), diethanolamine (DEA), N-methyldiethanolamine (MDEA), 2-amino-2methylpropanol (AMP), piperazine or 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU); the amino acid is selected as a proteinogenic amino acid. Preferably, the amino acid is selected as arginine (Arg), asparagine (Asn), aspartate (Asp), cysteine ​​(Cys), glycine (Gly), histidine (His) or lysine (Lys), as well as their optical isomers and their alkali metal salts. More preferably, the amino acid is selected as L-arginine (Z_-Arg), L-asparagine (L-Asn), L-aspartate (L-Asp), L-cysteine ​​(L-Cys), glycine (Gly) or L-lysine (L-Lys) or one of its derivatives of formula (III). in which n is an integer equal to 1, 2, 3 or 5, as well as their alkali salts. Preferably, the amino acid is chosen as being an alkali salt of L-lysine (L-Lys) or one of its derivatives of formula (III) in which n is an integer equal to 1, 2, 3 or 5. Most preferably, the amino acid is chosen as being an alkali salt of L-lysine (L-Lys); the concentration of amine function in the solution is at least 4M, more preferably at least 5M, more preferably greater than 5M, more preferably at least 6M, and most preferably at least 8M; the concentration of amine function in the solution is at most 50M, preferably at most 25M, more preferably at most 15M, most preferably at most 10M; and / or the amine or amino acid is dissolved in an aqueous solution or an organic solution. Preferably, the amine or amino acid is dissolved in water or a mixture of water and alcohol, the water:alcohol ratio of which is preferably between 1:10 and 10:1, more preferably between 1:5 and 5:1.Preferably, the alcohol is selected as methanol, ethanol, propanol, or isopropanol; more preferably, the alcohol is selected as methanol.

[0040] At the end of step a) of the process according to the present invention, the solution obtained is brought into contact with a gas containing CO2 (step b)). Preferably, step b) of the process according to the present invention is carried out under the following conditions, taken alone or in combination: the gas containing CO2 is an industrial combustion or exhaust gas. Preferably, the gas containing CO2 is an exhaust gas from a cement plant, a steelworks, a coal, gas or fuel power plant. More preferably, the gas containing CO2 is an exhaust gas from a cement plant or a coal power plant; the contacting is carried out at a temperature ranging from 10°C to 70°, preferably from 15°C to 65°C, more preferably from 20°C to 60°C; and / or the contacting is carried out under a total pressure varying from 0.7 to 10 Bars, preferably from 0.8 to 5 Bars, more preferably from 1 to 3 Bars.

[0041] At the end of step b) of the process according to the present invention, the concentrated solution or the precipitate obtained is brought into contact with an oxide, a silicate, an aluminate, a phosphate, a chloride or a sulfate of alkaline earth metal or a material containing an oxide, a silicate, an aluminate, a phosphate, a chloride or a sulfate of alkaline earth metal under grinding or under stirring (step c)).Preferably, step c) of the process according to the present invention is carried out under the following conditions, taken alone or in combination: the concentrated solution or the precipitate obtained is brought into contact with an alkaline earth metal oxide or silicate or a material containing an alkaline earth metal oxide or silicate; the alkaline earth metal oxide is chosen as being CaO or MgO; the alkaline earth metal silicate is chosen as being CaSiOs or MgSiOs; the alkaline earth metal hydroxide is chosen as being Ca(OH)2 or Mg(OH)2; the contacting is carried out in the presence of water or a water / solvent mixture; and / or the contacting is carried out at a temperature ranging from 10°C to 40°, more preferably from 15°C to 30°C.Most preferably, the contacting is carried out at room temperature; the energy used for stirring or grinding is at least 10W per gram of stirred or ground sample, preferably at least 15W per gram of stirred or ground sample, most preferably at least 20W per gram of stirred or ground sample; and / or the energy used for stirring or grinding is at most 500W per gram of stirred or ground sample, preferably at most 200W per gram of stirred or ground sample, most preferably at most 100W per gram of stirred or ground sample.

[0042] The stirring of the concentrated solution can be carried out with any suitable equipment known to those skilled in the art.

[0043] The precipitate can be ground using any suitable equipment known to those skilled in the art. Preferably, the precipitate is ground using a planetary mill, a ball mill, a knife mill, a ring mill, or by means of jar grinding with ceramic balls.

[0044] When a precipitate is obtained at the end of step b), it is preferably filtered and washed before being brought into contact with an oxide, a silicate, an aluminate, a phosphate, a chloride or a sulfate of an alkaline earth metal or a material containing an oxide, a silicate, an aluminate, a phosphate, a chloride or a sulfate of an alkaline earth metal under grinding during step c). Preferably, the filtration and washing are carried out under the following conditions, taken alone or in combination: the washing is carried out with a solution containing water and / or alcohol. More preferably, the washing is carried out with a mixture of water and alcohol whose water:alcohol ratio is preferably between 1:1 and 1:5.Preferably, the alcohol is chosen as being methanol, ethanol, propanol, or isopropanol; more preferably, the alcohol is chosen as being methanol; the washing solutions are combined and are reused in step a) of the process according to the invention; the washing is followed by a drying step. Preferably, the washing is followed by a drying step carried out at a temperature ranging from 5°C to 400°C, more preferably at a temperature ranging from 20°C to 300°C; and / or the filtration and washing are carried out under vacuum.

[0045] At the end of step c) of the process according to the present invention, the solid obtained is filtered and washed (step d)). Preferably, step d) of the process according to the present invention is carried out under the following conditions, taken alone or in combination: the washing is carried out with water; the washing solutions are combined and are reused in step b) of the process according to the invention; and / or the washing is followed by a drying step. Preferably the washing is followed by a drying step carried out at a temperature of up to 400°C.

[0046] The alkaline earth metal carbonates obtained at the end of the process according to the present invention are insoluble and stable and therefore allow CO2 to be stored sustainably. They are also reusable in various ways, for example as filler in cement production, as mineral filler in various products or as an amendment.

[0047] The present invention may be illustrated in a non-limiting manner by the following examples. Example 1 - Method for capturing and storing CO2 according to the invention

[0048] 1.1 - CO2 capture a / Process

[0049] Amino acid

[0050] 1g of amino acid and one equivalent of KOH are dissolved in 6ml of a distilled water / methanol mixture in a water:methanol ratio of 1:5.

[0051] CO2 is introduced into the solution thus formed at 200 mg / min for 1 hour. The formation of a white precipitate is observed.

[0052] At the end of the reaction, the precipitate is filtered through a frit, washed cold with a mixture of water / methanol (ratio 1:5) and dried under vacuum for 12 hours.

[0053] The injected quantity of CO2 is monitored gravimetrically and the total load of captured CO2 is confirmed by quantitative 13C NMR analysis.

[0054] The amino acids used in this process are lysine, glycine and cysteine.

[0055] Industrial amine

[0056] A concentrated 5M solution of diethylenetriamine (DETA) is prepared from commercial DETA and distilled water in a volumetric flask.

[0057] The solution is charged with a CO2 flow of 200mg / min using a flow meter.

[0058] The injected quantity of CO2 is monitored by gravimetry and the total load of CO2 captured is confirmed by quantitative 13C NMR analysis. b / Results

[0059] Table 1 - Quantity of CO2 captured by the amino acid or amine

[0060] In this table, the amount of CO2 captured by the amino acid / amine corresponds to the ratio of moles of CO2 to moles of nitrogen.

[0061] 1.2 - CO2 storage a / Process

[0062] I) Dry grinding

[0063] 0.3 g of solid α-amino acid-CC>2 obtained in Example 1.1 is introduced into a 20 ml tungsten carbide (WC) mechanochemistry reactor with 60 5 mm diameter balls.

[0064] The alkaline earth metal oxide is introduced in stoichiometric quantity relative to CO2.

[0065] Grinding is carried out at 500 rpm for 30 minutes.

[0066] The resulting solids are collected using 5 ml of distilled water, centrifuged and washed 3 times.

[0067] The liquid and solid phases are separated and dried using a freeze dryer. ii) Liquid Assisted Grinding (LAG) - Amino acid

[0068] 0.3 g of solid α-amino acid-CC>2 obtained in Example 1.1 is introduced into a 20 ml tungsten carbide (WC) mechanochemistry reactor with 60 5 mm diameter balls.

[0069] The alkaline earth metal oxide is introduced in stoichiometric quantity relative to CO2.

[0070] A defined amount of water is added to the reactor with a liquid:solid ratio between 0.1 and 2 pL / mg.

[0071] Grinding is carried out at 500 rpm for 30 minutes.

[0072] The resulting solids are collected using 5 ml of distilled water, centrifuged and washed 3 times.

[0073] The liquid and solid phases are separated and dried using a freeze dryer. iii) Liquid Assisted Grinding (LAG) - Amine

[0074] 1 ml of the DETA-CO2 solution obtained according to example 1.1 is introduced into a 20 ml tungsten carbide (WC) mechanochemistry reactor with 60 5 mm diameter balls.

[0075] The alkaline earth metal oxide is introduced in stoichiometric quantity relative to CO2.

[0076] Grinding is carried out at 500 rpm for 30 minutes.

[0077] The resulting solids are collected using 5 ml of distilled water, centrifuged and washed 3 times.

[0078] The liquid and solid phases are separated and dried using a freeze dryer. b / Results

[0079] Amino acid / amine regeneration rate

[0080] The regeneration rate of the amino acid or amine is determined by elementary analysis of the quantity of nitrogen N in the solid according to the following procedure, which corresponds to: (number of moles introduced - number of moles retained) / number of moles introduced x 100.

[0081] The solid phase is analyzed by CHNS to obtain the mass percentage of the various elements present. The percentage can be converted into moles of each element according to the following equations:

[0082] %N / 100 = g N in 1 g of solid sample (1)

[0083] Eq. (1) x exact mass of the sample = g N in the sample studied (2) Eq. (2) / 14.008 (atomic mass of nitrogen) = moles of N (3)

[0084] After obtaining the number of moles of N in the sample, the number of moles of amino acid / amine is obtained by dividing the number of moles of nitrogen by the number of nitrogens present on the amine (eg 3 for DETA and 2 for lysine):

[0085] Moles of N (3) / #nitrogens present on the amino acid / amine = moles of amino acid / amine

[0086] (4)

[0087] From the number of moles of amine in the solid sample, the amino acid / amine regeneration rate (TR) can be calculated according to the following equation:

[0088] TR (%) = (Moles of initial amino acid / amine - moles of amino acid / amine in the sample) / moles of initial amino acid / amine (5)

[0089] Carbonation rate of alkaline earth metal oxide

[0090] The carbonation rate of the alkaline earth metal oxide (ratio of moles of CO2 fixed in the solid phase per mole of alkaline earth metal oxide) is determined: by volumetric titration of the CO2 expelled during the acid digestion of the solid obtained (dosage of the so-called "inorganic" carbonate) on a Chittick apparatus with a 3 ml burette: an aliquot of dry solid of approximately 10 mg is titrated with 1 ml of 1 M H2SO4 acid. The calibration of the apparatus is done beforehand with NaHCOs titrated with 1 M H2SO4, thus obtaining a calibration curve of y=13.225 with R2=0.9943; and by elemental analysis of the carbon content (so-called total) after deduction of the possible contribution of the trapped amine: the nitrogen content of the solid makes it possible to go back to the quantity of amine and therefore of carbon coming from the amine in the solid. Subtracting from the total amount of carbon in the solid, we deduce the amount of carbon coming from the fixed CO2

[0091] These two measurements are confirmed by q13C NMR on the liquid phases to confirm the quantity of amine: an aliquot of the liquid phase is analyzed by NMR in the presence of an internal reference to allow quantification of the amine in solution.

[0092] The carbonation rate is calculated following the same principle as for calculating the amine / amino acid regeneration rate.

[0093] Equations (1), (2) and (3) above are adapted by dividing by the atomic mass of carbon.

[0094] The number of moles of CO2 in the solid phase is calculated by subtracting the number of moles of amino acid / amine from the number of moles of carbon:

[0095] Moles of CO2 = moles of C - (moles of amino acid / amine x #C in amino acid / amine) (6)

[0096] In equation 6 the number of moles of amine were calculated by eq. (4) and the #C varies according to the amino acid / amine (eg 4 for DETA and 6 for lysine).

[0097] The carbonation rate (CT) is then calculated as:

[0098] TC (%) = moles of CO2 / moles of initial CO2 (7)

[0099] Dry grinding (neat grinding) with amino acid

[0100] Table 2 - Metal oxide carbonation rate and amino acid regeneration rate - Dry route

[0101] Grinding by LAG with amino acid

[0102] Table 3 - Metal oxide carbonation rate and amino acid regeneration rate - LAG route LAG grinding with amine

[0103] Table 4 - Metal oxide carbonation rate and amine regeneration rate - LAG route

[0104] 1.3 - Conclusion

[0105] The experimental results obtained confirm that the process according to the present invention makes it possible to carry out the carbonation step of the alkaline earth metal oxide by dry means or in the presence of very small quantities of water, which significantly limits the quantities of water required in comparison with the processes conventionally implemented.

[0106] Furthermore, the reaction kinetics, the carbonation rate of the alkaline earth metal oxide and the regeneration rate of the amino acid or amine used are significantly higher than for conventionally used processes (see for example Liu et al., “Single-step, low temperature and integrated CO2 capture and conversion using sodium glycinate to produce calcium carbonate”, Fuel (2020), Ed. 275, 117887, or Liu et al., “Integrated CO2 Capture and Removal via Carbon Mineralization with Inherent Regeneration of Aqueous Solvents”, Energy & Fuels (2021), 35 (9), 8051-8068)).

Claims

DEMANDS 1. A mechanochemical process for capturing and storing CO2 comprising the following steps: a) dissolving an amine or amino acid to obtain a concentrated solution having an amine functional group concentration of at least 3M; b) contacting the solution thus obtained with a gas containing CO2; c) 1. contacting the concentrated solution obtained in step b) with an oxide, hydroxide, silicate, aluminate, phosphate, chloride, or sulfate of an alkaline earth metal, or a material containing an oxide, silicate, aluminate, phosphate, chloride, or sulfate of an alkaline earth metal, the energy used for stirring being at least 2.5 W per gram of the sample stirred; or 2. contacting the precipitate obtained in step b) under grinding with an oxide, hydroxide, silicate, aluminate, phosphate, chloride or sulfate of an alkaline earth metal or a material containing an oxide, silicate, aluminate, phosphate, chloride or sulfate of an alkaline earth metal, the energy used for grinding being at least 2.5 W per gram of the sample ground; and d) washing the solid obtained.

2. A process according to claim 1, characterized in that the concentration of the amine function of the concentrated solution obtained in step a) is at least 5M.

3. A method according to claim 1 or 2, characterized in that the energy used for stirring or grinding during step c) is at least 5 W per gram of sample.

4. A method according to any one of claims 1 to 3, characterized in that the energy used for stirring or grinding in step c) is at most 500 W per gram of sample.

5. A process according to any one of claims 1 to 4, characterized in that step c.2) is preceded by a step of filtration and washing of the precipitate obtained in step b).

6. A process according to any one of claims 1 to 5, characterized in that the amine is chosen to be ethylenediamine (EDA), diethylenetriamine (DETA), monoethanolamine (MEA), diethanolamine (DEA), N-methyldiethanolamine (MDEA), 2-amino-2-methylpropanol (AMP), piperazine or 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU).

7. A method according to any one of claims 1 to 6, characterized in that the amino acid is chosen to be a proteinogenic amino acid.

8. A process according to claim 7, characterized in that the amino acid is chosen to be L-arginine (Z-Arg), L-asparagine (L-Asn), L-aspartate (L-Asp), L-cysteine ​​(L-Cys), glycine (Gly), histidine (His) or L-lysine (L-Lys), as well as their alkali salts.

9. A process according to claim 8, characterized in that the amino acid is chosen to be L-lysine (L-Lys).

10. A process according to any one of claims 1 to 9, characterized in that the organic solution is a water / alcohol mixture in a water:alcohol ratio between 1:10 and 10:

1.

11. A method according to any one of claims 1 to 10, characterized in that the gas containing CO2 is an industrial combustion or exhaust gas.

12. A process according to claim 11, characterized in that the gas containing CO2 is an exhaust gas from a cement plant.

13. A process according to any one of claims 1 to 12, characterized in that the precipitate obtained at the end of step c) is brought into contact with an oxide or silicate of an alkaline earth metal or a material containing an oxide or silicate of an alkaline earth metal.

14. A process according to claim 13, characterized in that the alkaline earth metal oxide is chosen to be CaO or MgO.

15. A process according to claim 13, characterized in that the alkaline earth metal silicate is chosen as CaSiOs or MgSiOs.

16. A process according to claim 13, characterized in that the alkaline earth metal hydroxide is chosen to be Ca(OH)2 or Mg(OH)2.

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