Patent Application
20240091719
The subject of the present invention is an apparatus and a method for the accelerated dissolution of carbonates or, in other words, for the generation of a pH-buffered ionic mixture, in an economical and environmentally sustainable form.
The effects of so-called “greenhouse gases” on the climate have long been known, especially the correlation between the concentration of CO2 (carbon dioxide) in the atmosphere and global warming.
The efforts of the world's scientific and political community in recent years have been concentrated on trying to counteract the increase in greenhouse gas emissions into the atmosphere, in order to prevent the phenomenon of global warming, i.e. the rise in the average global temperature.
As is well known, a number of initiatives have been promoted at international level to limit CO2 emissions into the atmosphere: the Kyoto Protocol in 1997 and the Paris Agreement in 2015, among others, are worth mentioning.
The ways identified by the scientific community to prevent global warming are multiple and basically concern the decrease in the use of fossil fuels such as coal, oil and natural gas by promoting the development of renewable energies such as hydro, wind, solar and biomass energy.
In addition, many efforts of the international community are focused on improving the efficiency of energy use, such as lighting with low-consumption light bulbs, transport with new generations of high-efficiency engines and, in the field of power generation, replacing old, inefficient coal- or oil-fired power stations with new combined-cycle gas turbine and steam turbine plants with energy efficiencies approaching 60%.
Despite the technological efforts being made in the most advanced nations, forecasts by well-known international institutions of global energy needs over the next few years indicate a sharp increase in demand for electricity, thermal energy for industry and fuels for transport.
As a result, these forecasts unfortunately still indicate an increase in the use of fossil fuels such as oil, coal and natural gas, especially by emerging, newly industrialised and developing countries as the development of renewable energies and the possibility of storing CO2 in permanent form from fossil fuel plants are not growing at the rate needed to meet the goals of the Paris agreement of 2015.
Using the data provided by these authoritative studies, a rapid decrease in CO2 emissions to counteract global warming is not expected at global level in the near future, despite the efforts and environmental policies implemented by several countries, mainly due to the increase in world population and the new industrialisation of entire countries.
Different technologies have been proposed to capture and sequestrate the CO2 produced by industrial and power generation plants using fossil fuels. Generally, all these technologies involve separating CO2 from other gases by chemical/physical means.
Most of the proposed capture and storage technologies relate to concentrated CO2 emissions such as those present in the flue gas of power plants or industrial installations.
The main CCS technologies proposed and known are:
Sequestration of CO2 using EWL technology has considerable advantages over other known technologies because the availability of carbonate rocks is very large, because the sea is very rich in bicarbonates and therefore the addition of new bicarbonates does not pose any environmental problems, because it does not require the monitoring of the storage site and because the technology can be used in modular plants and its application can be industrialised and programmable.
Sequestration of CO2 with EWL reactors as proposed and described in the U.S. Pat. No. 6,890,497 B2 and KR 101888 684 B1 and by numerous scientific articles has some important problems that limit its applicability such as the large quantities of water needed for the process, the long reaction times, the possible acidification of seawater and the problems of CO2 outgassing and the consequent decrease in storage efficiency.
In fact, the EWL technologies proposed up to now envisage a reactor in which the reaction of carbonate dissolution with water and CO2 takes place, and the release of an ionic solution of bicarbonates into the sea through a duct whose sole function is to convey the ionic solution of bicarbonates into the sea and in which no chemical reactions of carbonate dissolution take place.
From the published scientific literature on EWL technology, it is easy to see that, in the best-case scenario, about 3,800 m3 of seawater is needed to store one tonne (one metric ton, i.e. 1000 kg) of CO2 in the form of bicarbonates, and that this amount of bicarbonate-rich water is the water that must be discharged into the sea through a special duct.
Moreover, the scientific literature published on EWL technology and the results of the experimental plants built show that the ionic mixture discharged by the EWL reactors proposed so far has a pH of approximately 6 and that, if discharged into the deep sea, it would lead to the acidification of the sea, while if the ionic mixture discharged by the EWL reactors were discharged into surface waters it would have to be degassed, with a significant loss of CO2 storage efficiency.
In EWL technology, releasing an effluent already in an ionic state (ionic mixture), in which all the carbonate is dissolved in the effluent, implies the use and transport of large quantities of water to the desired depth and long residence times, even tens of hours, which in the reactors proposed so far installed on land makes this option technically and economically impracticable, also because of the enormous size of the reactors themselves.
As can be immediately understood, there is a need to find a method and an apparatus that will allow carbonates to be dissolved in an accelerated form using low quantities of water, without acidifying the sea, with greater efficiency than the EWL reactors proposed so far and with an acceptable cost to allow its rapid and massive application.
The task of the present invention is to make available a method and apparatus that can enable the complete dissolution of the carbonates present in a mixture of CO2, water and carbonates and the release into the sea of an ionic mixture of water and bicarbonates with a pH similar to that of the sea for the permanent storage of CO2, which can be realised in modular form and implemented on a global scale.
Said purpose and tasks are achieved by means of an apparatus and method for the accelerated dissolution of carbonates with buffered pH according to claims 1 and 12, respectively. The method according to the invention may also be called BEWL (BUFFERED ENHANCED WEATHERING of LIMESTONE).
In order to better understand the invention and appreciate its advantages, some exemplary and non-limiting embodiments of the invention are described below, with reference to the accompanying drawings, in which:
In the description, reference will be made to “carbonic gas”, meaning a gas mixture containing CO2, and possibly other substances including H2, CO, CH4, N2, O2, H2S, SO2, NO, whereas when reference is made to the chemical element CO2 (carbon dioxide) alone, CO2 will be used the description.
In the description, reference will also be made to “water”, meaning sea or lake water, fresh, salt or brackish, whereas when reference is made to the chemical element H2O alone in the description, H2O will be used the description.
In the description, reference will also be made to the “sea”, meaning not only the sea itself, but also an ocean or any salt or brackish water.
In the description, reference will also be made to the “depth” of the sea, meaning the vertical distance from the sea level in the direction of the force of gravity; in particular, a greater or larger “depth” means a longer distance from the sea surface and a lesser or smaller “depth” means a shorter distance from the sea surface.
In the description reference will also be made to the “weighted average pressure”, meaning the sum of the pressures within the dissolution reactor 14 multiplied by the residence time and divided by the total time according to the formula:
where Pi is the pressure in time interval i and Si is the duration time of time interval i.
In the description, reference will be made to a “reactor”, meaning an apparatus in which chemical reactions take place in a continuous way rather than in batch form.
In the description, reference will be made to a “chamber” meaning a part of the mixer 12 in which the formation of a lean mixture (defined below) takes place irrespective of its shape and size.
In the description, reference will be made to “carbonate” or “carbonates”, meaning a solid material consisting mainly of CaCO3 and MgCO3 in particle sizes comprised between 0.1 microns and 50 microns, even in an aqueous suspension. When reference is made to the chemical element CaCO3 or MgCO3 alone, the description will use CaCO3 or MgCO3, respectively. In the description and the formulae, CaCO3 will be used as an example of a carbonate, with the understanding that the arguments are also valid for MgCO3 and for carbonate rocks containing them in various proportions, such as limestone, dolomite CaMg(CO3)2, marble and travertine.
In the description, reference will be made to “aragonite”, meaning a carbonate formed mainly from CaCO3 that crystallises in the bipyramidal rhombic class and is a polymorph of calcite precipitated from seawater in biotic form. Aragonite can be found in many marine organisms, shells, corals and consequently in coral and “Oolitic aragonite sands” of which the Bahamas has large deposits.
In the description, reference will be made to “calcite”, meaning a carbonate formed mainly from CaCO3 that crystallises in the trigonal class. Calcite is commonly found in limestone or dolomitic deposits and is the most widespread carbonate in the earth's crust.
In the description, reference will be made to “bicarbonates”, meaning the chemical compounds Ca(HCO3)2 and Mg(HCO3)2. In the description and in the formulae, Ca(HCO3)2 will be used as an example of bicarbonates, it being understood that the reasoning also applies to Mg(HCO3)2.
In the description, reference will be made to “hydroxide”, meaning calcium hydroxide Ca(OH)2, magnesium hydroxide Mg(OH)2 in powder or suspension form or in solution with an appropriate quantity of water. In the description and in the formulas, Ca(OH)2 will be used as an example of a hydroxide, it being understood that the reasoning also applies to Mg(OH)2, for the hydroxide obtained from the calcination of minerals containing them, such as calcite, aragonite, dolomite and magnesite.
In the description, reference will be made to the “mixture”, meaning a slurry of water, CO2, carbonate, bicarbonates and impurities in which the percentage by weight of carbonates in the mixture is comprised between 0% and 10% and in which some elements, such as carbonates and solid impurities, are in suspension and other elements, such as CO2 and bicarbonates, are in solution.
In the description, reference will be made to the “design flow rate”, meaning the sum of the quantities of water, CO2, carbonates, bicarbonates and impurities that are released in the unit of time from the mixer 12 to the dissolution reactor 14 and that allows the permanent sequestration of a predetermined quantity of CO2.
In the description, reference will be made to the “lean mixture”, meaning a slurry of water, CO2, carbonates, bicarbonates and impurities in which the proportion of carbonates which have dissolved in the water supplied to mixer 12 in relation to the carbonates supplied to the mixer 12 is less than 10%. A solution of only water and CO2 in which no carbonates are present is also considered a lean mixture.
In the description, reference will be made to the “ionic mixture”, meaning a mixture where all the carbonate present has dissolved and the Ca2+ or Mg2+ is in ionic form. An ionic mixture is also considered to be a solution of only water and CO2 in which no carbonates are present; in this particular case the lean mixture chemically coincides with the ionic mixture.
In the description, reference will be made to “buffered ionic mixture”, meaning an “ionic mixture” in which the pH has been corrected to the desired value by the addition of a hydroxide. In cases where the hydroxide is readily soluble, the “buffered ionic mixture” is an ionic solution. In cases where the hydroxide has low solubility due, for example, to high Mg content, the “buffered ionic mixture” may be a slurry formed from the “ionic mixture” and the undissolved hydroxide.
In the description, reference will be made to “Ωcal” meaning the calcite saturation state in seawater. The SIcal (Saturation Index Calcite) referred to in the attached figures is related to fca by the formula SIcal=log10(Ωcal).
In the description reference will be made to “impurities” meaning solid, liquid or gaseous substances present in the carbonate, in the gas containing CO2 or in the water which do not take part in the chemical reactions according to the invention.
In the description, reference will be made to the “plume”, i.e. the portion of the sea where the mixture released from the reactor is mixed and diluted with the surrounding sea water.
In the description, reference will be made to the “residence time of the mixture”, i.e. the time in which the mixture is able to pass through the duct 141.
In the description, reference will be made to “pH”, meaning the measurement scale that indicates the acidity or basicity of a liquid which is defined by the following formula:
pH=−log10[H3O+]
In the description, reference will be made to “alkalinity”, meaning the amount of hydroxides OH−, carbonates CO32− and bicarbonates HCO32− present in seawater.
In the description reference will be made to “hardness” meaning a value expressing the total content of Ca2+ and Mg2+ ions in seawater.
In the description, reference will be made to the “carbonate dissolution reaction”, meaning the following reaction:
CO2(g)+CaCO3(s)+H2O=>Ca2+(aq)+2HCO3−(aq) [1]
where Ca2+ can be replaced by Mg2+ if present in the carbonate.
In the description, reference will be made to the “Reynolds number Re”, meaning the dimensionless number used in fluid dynamics proportional to the ratio between the inertia forces and viscous forces.
In the description reference will be made to “OD” meaning Outside Diameter, or the diameter of a pipe with a circular section or a circular tubular structure with the same hydraulic characteristics as the tubular structure under consideration.
In the description, reference will be made to the “SDR”, meaning the Standard Dimensional Ratio of a pipe defined as the ratio of the outside diameter OD to the wall thickness of the pipe.
In the description, reference will be made to “PE”, meaning the plastic material HDPE—High Density Poly Ethylene or LDPE—Low Density Poly Ethylene;
In the attached figures, an apparatus for the accelerated dissolution of carbonates with buffered pH is indicated overall by the reference 100. The apparatus 100 may advantageously comprise one or more of the following components: a logistics base 300, a storage facility 40 for carbonic gas (not shown in the figures), a carbonate storage facility 30, a hydroxide storage facility 45, an apparatus 10 for preparing a buffered ionic mixture by total reaction of carbonate with water and CO2 in the dissolution reactor 14 and final pH correction by hydroxide in the pH correction reactor 24. The logistics base 300 may include an off-shore platform or a ship (not shown in the figures).
The apparatus 100 may further comprise means 42 for supplying carbonic gas. For example, the logistics base 300 can be connected to an appropriate pipeline for transporting the carbonic gas. More specifically, the off-shore platform can be connected to the coast by a suitable pipeline for transporting the carbonic gas or housing a plant on board to produce it. Alternatively, other known methods of transporting carbonic gas can be used, e.g. by means of pressurised containers loaded onto special transport vehicles and/or vessels.
The apparatus 100 for the accelerated dissolution of carbonates with buffered pH, comprises a mixer 12, a dissolution reactor 14 and a pH correction reactor 24 wherein the mixer 12 comprises:
CaCO3+CO2+H2O→Ca(HCO3)2
Ca(OH)2+2CO2→Ca(HCO3)2
In accordance with some embodiments of the invention, the apparatus 100 for the accelerated dissolution carbonates with buffered pH further comprises mixing means 125 adapted to uniformly disperse the carbonic gas and carbonate in water so as to form the lean mixture 130.
In accordance with some embodiments, the apparatus 100 for the accelerated dissolution of carbonates with buffered pH further comprises means for evacuating non-soluble gases 129.
In accordance with some embodiments of the invention, the apparatus 100 for the accelerated dissolution carbonates with buffered pH comprises a dissolution reactor 14 in which the duct 141 is made of plastic material, preferably PE, with an SDR>11, preferably with 33≤SDR≤50.
In accordance with some embodiments of the invention, the apparatus 100 for the accelerated dissolution carbonates with buffered pH is at least partially installed in the sea. In this case, the apparatus 100 is preferably anchored to the seabed.
In accordance with some embodiments of the invention, for example those schematically depicted in
In accordance with some embodiments of the invention, for example that shown schematically in
Preferably the auxiliary pipe 282 for transporting hydroxide 28 connects the hydroxide storage facility 45 with the section 60 where the hydroxide supply means 28 are positioned.
In accordance with some embodiments of the invention, the auxiliary hydroxide transport pipe 282 runs parallel or coaxial to the duct 141.
In accordance with some embodiments of the invention, the mixer 12 and the dissolution reactor 14 may be implemented as a single seamlessly integrated apparatus between the mixer 12 and the dissolution reactor 14. In such a case, the section 55 represents the section where the dissolution reactor 14 is hydraulically connected to the mixer 12 and where the lean mixture 130 begins to be present.
In accordance with some embodiments of the invention, the dissolution reactor 14 and the pH correction reactor 24 may be implemented as a single, seamlessly integrated apparatus between the dissolution reactor 14 and the pH correction reactor 24. In such a case, the section 60 represents the section where the dissolution reactor 14 is hydraulically connected to the pH correction reactor 24 and where the hydroxide supply means 28 are positioned.
In accordance with some embodiments of the invention, the mixing means 125 positioned in the mixer 12 may be implemented by means of spray nozzles, static mixers, scrubber packing or, referring to
CO2+H2O→H2CO3→H++HCO3−.
Referring to the embodiments of
In accordance with the embodiments of the apparatus 10 according to the invention represented schematically in
In accordance with the embodiments schematically represented in
In a known form, the carbonate dissolution process is a process with very slow kinetics which therefore requires very long residence times in the reactor of the water, CO2 and carbonate mixture and very large contact surfaces between the carbonate and the water.
An experienced person can clearly understand that using micron-sized carbonate particles instead of millimetre-sized carbonate particles increases the contact surface between carbonate and water in the mixture and promotes the dissolution reaction.
In a known form, the carbonate dissolution reaction is favoured by low pH and strongly undersaturated mixtures compared to calcite, i.e. with negative SI.
In a known form, as the partial pressure of CO2 increases, the degree of hydration of CO2 increases, the formation of carbonic acid H2CO3 and the consequent decrease in pH.
As stated above, the solubility of carbonate in water increases as the pH decreases and the pressure increases within the saturation limits of Ca2+ in the water. Low pH levels and high pressures promote the dissolution of the carbonate which, as it dissolves, consumes the CO2 dissolved in the water, thus increasing the pH of the mixture inside the dissolution reactor 14.
An experienced person will certainly understand the advantages of using a tubular reactor which can easily be placed on the seabed and thus take advantage of hydrostatic pressure, can be very long with high residence times of the mixture, can easily keep the mixture inside it in a turbulent regime allowing it to easily handle finely micronised carbonate by optimising the reaction surface thereof.
An experienced person will, as mentioned above, certainly understand that by placing the dissolution reactor 14 on the seabed, it is possible to conveniently exploit the hydrostatic pressure proportional to the installation depth of the dissolution reactor 14 by promoting carbonate dissolution reactions according to the reaction [1].
An experienced person can easily deduce that according to the reaction [1] and considering the special case in which the carbonate was calcite or aragonite, about 2272 kg of CaCO3 and about 409 kg di H2O are required to stoichiometrically react 1000 kg of CO2.
An experienced person will certainly understand that the amount of water in the lean mixture 130 required to keep the mixture sufficiently fluid and to obtain complete dissolution of the carbonate and thus the ionic mixture 131, is greater than the stoichiometric quantities required according to equation [1].
In accordance with some embodiments of the invention, and with particular reference to
An experienced person can readily understand if it is desired that all the carbonate fed to mixer 12 be dissolved in the dissolution reactor 14, it is desirable to supply to the mixer 12, for the same amount of CO2, less carbonate than is required stoichiometrically according to equation [1] with the result that in the ionic mixture 131 released from the dissolution reactor 14 there is a quantity of CO2 that has not reacted with the carbonate which, if discharged into the sea, would lower its pH unless properly buffered with a basic substance. All the carbonate supplied to the reactor 12 and not reacted with CO2 at the end of the dissolution reactor 14 would be released into the sea in a solid state with the ionic solution 131 or buffered ionic solution 132 and represents a waste of material.
Referring to
Referring again to the tables in
An experienced person, referring to the tables in
An experienced person, referring again to the data shown in
An experienced person will certainly be able to understand that the tubular configuration of the dissolution reactor 14 according to the invention and above all the possibility, known in itself, of making large-diameter pipes of plastic material such as PE by means of a continuous extrusion process, makes it possible to construct EWL reactors with large residence times in a more modular and economical form than the reactors hitherto proposed for storing CO2 in the form of bicarbonates in the sea.
An experienced person will certainly understand that the dissolution reactor 14 according to the invention can easily handle micronised carbonate which provides a larger reaction surface area than using carbonate with a larger size. In the reactors already proposed for EWL technology, means for the continuous mixing of carbonate with water, such as circulation pumps or agitators, are required, with considerable energy consumption. In the case of the dissolution reactor 14 according to the invention, the very movement of the mixture within the dissolution reactor 14 generates the turbulence necessary to keep the carbonate constantly mixed with the water.
In addition, the installation of the dissolution reactor 14 on the seabed also minimises the energy required to pump water into the dissolution reactor 14 compared to the energy required to pump the same amount of water for a known EWL reactor on land because, in addition to the pressure drop due to the movement of the mixture inside the reactor, there is the pumping energy due to the fact that the reactor on land is generally installed above sea level.
In the event that sizing the duct 141 according to the above criteria poses economic, logistical or environmental problems, it is possible to reduce the length of the duct 141 by supplying more hydroxide 28 to the chamber 123 of the mixer 12. In this case, the carbonic gas 127 reacts with hydroxide 28 according to the reaction:
Ca(OH)2+2CO2→Ca(HCO3)2.
As an experienced person can understand, in this way it is possible to drastically reduce, or even cancel out, the required length of the duct 141.
Referring to
In a known form, the amount of gaseous CO2 that is dissolved in the water of the mixture is directly proportional to the partial pressure of the CO2 in the carbonic gas and inversely proportional to the temperature at which it is inside the apparatus 10 for preparing a buffered ionic mixture.
An experienced person will certainly be able to see that, in order to make the most of the dissolution of CaCO3 within the dissolution reactor 14 and to minimise the amount of water required in the mixture, it is advisable for the residence time Tmin of the mixture in the reactor to be greater than 1000 s (approx. 17 minutes), preferably comprised between 1500 s (25 minutes) and 10000 s (approx. 3 hours). From a qualitative point of view, the residence time is shorter the smaller the particle size of the CaCO3 used. Shorter residence times can be achieved, for example, by using what is known as precipitated calcium carbonate (or PCC).
In a known form, in order to prevent sedimentation of the solid components of a slurry, it is necessary to maintain a minimum velocity V1 (limit velocity) of the slurry in any duct: this velocity is calculated using the well-known Duran formula. For particulate matter in the slurry of less than 50 microns and with a density of less than 2700 kg/m3, no sedimentation problems are considered as long as the velocity of the slurry in the duct is maintained in a turbulent regime, i.e. with a Re≥4000. For example, with a diameter of 3600 mm (3.6 m) already with a slurry velocity inside the duct 141 of 0.1 m/s the turbulent regime criterion is met.
In accordance with some embodiments of the invention, the carbonate is fed to the mixer 12 in the form of a “slurry” suspension by means of the hydroxide supply means 28.
In accordance with a particular embodiment of the invention and with particular reference to
An experienced person can see that the presence of dissolved CO2 in the ionic mixture 131 lowers its pH because, in its known form, CO2 reacts with water to form carbonic acid, which in turn splits into a proton H+ and a bicarbonate HCO3− according to the chemical equilibrium CO2+H2O↔H2CO3↔H++HCO3− and lowering the pH of the mixture.
An experienced person can calculate that the pH of an ionic mixture 131 consisting of 2000 m3 of water and about 500 kg of dissolved CO2 has a pH of about 6.
An experienced person can clearly understand that discharging an ionic mixture 131 with a pH of 6 into the surface sea would result in the outgassing of CO2 to the atmosphere and a loss of efficiency in the storage of CO2 in the form of bicarbonates, whereas discharging an ionic mixture 131 with a pH of 6 into the deep sea would result in the acidification of the sea as CO2 remains dissolved in the deep sea. This is what happens in the proposed EWL reactors.
An experienced person will certainly understand that, in order not to damage the environment, it is necessary and appropriate to buffer the ionic solution 131 with a hydroxide. In this case the hydroxide would react with the remaining dissolved CO2, eliminating the problems of both acidification and outgassing mentioned above.
An experienced person may understand that it is possible to use hydroxide to correct the pH of the ionic mixture 131 released from the dissolution reactor 14 and fed to the pH correction reactor 24, buffering all or part of the CO2, still present therein, to release a buffered ionic mixture 132 with the desired pH into the sea using the equation:
2CO2(aq)+Ca(OH)2(aq)=>Ca2+(aq)+2HCO3−(aq) [2]
An experienced person can certainly understand that a certain amount of mixing time is required inside the reactor for the pH correction 24 of the hydroxide 28 with the ionic mixture 131 in order for the buffered ionic mixture 132 to be formed with a homogeneous pH throughout its volume, especially if the hydroxide 28 is supplied to the pH correction reactor 24 not in the form of a solution but in the form of a suspension (slurry) or in solid form.
An experienced person can understand that the duct 142 of the pH correction reactor 24 must have a sufficient length to ensure proper mixing of the hydroxide 28 with the ionic mixture 131: this length is comprised between 0 m and 20000 m, preferably between 10 m and 1000 m.
An experienced person can understand that the duct 142 of the pH correction reactor 24 may be provided with suitable means for mixing the hydroxide 28 with the ionic mixture: such mixing means, not shown in the figures, may be static mixers or a suitable arrangement of the hydroxide injection nozzles 28.
In accordance with a particular embodiment of the invention, in the event that the hydroxide 28 is a hydroxide with a high Mg content and therefore low solubility, it is convenient that the buffered ionic mixture 132 is released into the sea from the pH correction reactor 24 in the form of a suspension (slurry) with a part of the hydroxide not yet dissolved so that it can finish dissolving and buffering according to the reaction [2] in the plume 25. In such a case, the pH of the buffered ionic mixture 132 in section 65 would be lower than that of the surrounding seawater and would only reach the desired value after the hydroxide 28 finalises its dissolution in the plume 25.
In accordance with some embodiments of the invention and referring to
Referring to the table in
An experienced person can certainly understand that with the apparatus 10 for preparing a buffered ionic mixture according to the invention, conveniently exploiting the effect of the hydrostatic pressure of the tubular dissolution reactor 14 laid on the seabed, long residence times and small carbonate size, it is possible to reduce the amount of water and the time required for carbonate dissolution almost by an order of magnitude compared to the reactors already proposed for EWL technology with obvious economic and applicability benefits. Furthermore, the apparatus 10 for preparing a buffered ionic mixture according to the invention does not have the problems of CO2 outgassing or sea acidification typical of the EWL reactors proposed so far.
A second aspect of the invention relates to a method for the accelerated dissolution of carbonates with buffered pH. Said method comprises the steps of:
CaCO3(a)+CO2(aq)+H2O→Ca(HCO3)2(aq)
Ca(OH)2(aq)+2CO2(aq)→Ca(HCO3)2(aq);e
The method described above may also comprise the steps of:
It is understood that the specific features are described in relation to different embodiments of the apparatus 100 for the accelerated dissolution of carbonates with buffered pH aimed at permanent sequestration of CO2 in the form of bicarbonates with an illustrative and non-limiting intent.
To the apparatus 100 for the accelerated dissolution of carbonates with buffered pH for the permanent sequestration of CO2 in the form of bicarbonates according to the present invention, a person skilled in the art may, in order to meet contingent and specific requirements, make further modifications and variations, all of which are within the scope of protection of the invention as defined by the following claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 102021000003263 | Feb 2021 | IT | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/IB2022/051464 | 2/18/2022 | WO |
