Method and system for carbon capture

Abstract

Method of reacting carbon dioxide with a metal silicate, preferably a nesosilicate material such as olivine. The metal silicate particulate material is placed in a container having a container wall, with water in a bed or in a suspension in the water, and the particulate material is agitated. The agitation may occur via an air stream that is blown into the container via a diffusor. Alternatively, the particulate material is agitated by vibrating at least a part of the wall of the container. The abrasion of the particles that collide with each other continuously cleans the particle surface, and maintains a high reaction rate, allowing new CO2 to react with a continually refreshed interface.

Description

[0001] P138027PC00

[0002] Title : Method and system for carbon capture

[0003] Technical Field

[0004] The invention relates to a method of reacting carbon dioxide with a metal silicate and to a system for carrying out said method.

[0005] Background

[0006] Metal silicates, in particular olivine, which is a common mineral, have been recognized for their potential to capture carbon dioxide (CO2) from the atmosphere through a natural weathering process called mineral carbonation. However, the rate of this natural process is slow, having a scale of decades to centuries, limiting its effectiveness as a carbon capture and storage method. There is a need for a system and method to accelerate the mineralization of metal silicates, in particular olivine for efficient carbon dioxide capture and sequestration.

[0007] The present invention provides a novel system and method for accelerating the carbonation of metal silicates such as olivine, enhancing and accelerating its capacity to capture carbon dioxide. This system integrates, steers and optimizes conditions such as temperature, pressure, humidity, acidity, and the reactant flow resulting in accelerated and optimized mineralization of carbon dioxide. The system provides means to control the ratio of olivine, carbon dioxide and other reactants. Furthermore, dynamic conditions are provided under which the mineralization process is continuously activated, resulting in an accelerated olivine carbonation process.

[0008] Summary

[0009] A method of reacting carbon dioxide with a metal silicate, preferably a nesosilicate material such as olivine according to the disclosure comprises: - placing metal silicate particulate material in a container having a container wall, with water in a bed or in a suspension in the water, and -agitating the particulate material.

[0010] The method of the invention creates dynamic conditions in the container, or reactor vessel, during the carbonation process. By these dynamic conditions, the olivine particles are prevented from coagulating. The surface of the olivine particles is continuously cleaned by an abrasion-effect, exposing fresh surface on the olivine particles for the chemical processes to continue at a high rate. The abrasion of the particles that collide with each other, continuously cleans the particle surface, and maintains a high reaction rate, allowing CO2 to react with a continually refreshed interface.

[0011] The method according to the invention requires low amounts of renewable energy.

[0012] The dynamic conditions simultaneously create the optimal conditions for the dissolution of carbon dioxide to form carbonic acid and subsequently the breaking down of olivine into magnesium carbonate, water and silica. Furthermore, in the reactor vessel the environmental conditions can be controlled such as pH, temperature, and pressure to further optimize the carbonation process.

[0013] A big advantage of the process according to the invention is that creating the dynamic conditions requires a relatively limited energy input, using low energy sources to create the dynamic environment.

[0014] The container may be open or closed. In one embodiment, the container wall is bounding a reactor volume, the method comprising feeding an air stream at or near ambient pressure, into the container and contacting the metal silicate particles in the bed or in a suspension and maintaining the metal silicate particles at a temperature below 25 °C.

[0015] The water may comprise tap water having a conductivity of 50-800 microS / cm. Preferably the water comprises de-ionized water having a conductivity below 50 micro S / cm, preferably below 5 micro S / cm The particulate material, such as the mixture of water and ohvine, may be agitated via the air stream that is blown into the container through a diffusor.

[0016] The mixture of particulate material and water can be agitated by vibrating at least a part of the wall of the container. The vibrations may have a frequency within an ultrasonic range of 20 kHz - 1 GHz.

[0017] In an embodiment, the container comprises a substantially flat bottom wall, a transducer being coupled to the bottom wall for providing vibrations with a frequency in a range of 2-20kH, preferably in a frequency range of 50 Hz to 100 Hz.

[0018] It was found that the reaction rate of CO2 with the metal silicate can be increased by adding a peptide to the water to prevent the particles from clotting. In an embodiment, an alkaline additive is used

[0019] The container may comprise an air inlet and at least one diffusor located in the container, connected to the air inlet. The metal silicate particulate material in the water is agitated by the bubbles created by the diffusor, which keep the particles in a suspension and prevent them from settling down on the bottom of the reactor.

[0020] In an embodiment glycerine was added to the water in the container. By the thickening agent, the olivine particles are prevented from sticking together and remain mutually separated in the reactor vessel. This increases the reaction rate.

[0021] A successful experiment was carried out using 1800 gram of ohvine having a particle size of fine sand, 200 gram of olivine with a particle size of dust and 200 gram glycerine, mixed with 2000 gram of water.

[0022] A system for reacting carbon dioxide with a metal silicate, preferably a nesosilicate material such as ohvine comprises: a container having a container wall, a water supply - the container being adapted for containing particulate metal silicate material in a bed or in a suspension in the water, and agitating means for providing a reciprocating movement of the container, a vibrating movement of a part of the container wall or providing an agitating movement by contacting the particulate material in the container.

[0023] The water supply can comprise a demineralized water supply, such as a deionized water supply.

[0024] A container wall may bound a reactor volume, the system comprising an air supply for blowing air into the reactor volume via a diffusor for keeping the particulate material in suspension. The air supply can be adapted for feeding an air stream at or near ambient pressure, into the container.

[0025] The system may comprise a temperature control means arranged for maintaining the temperature of the metal silicate particles at a temperature below 25 °C.

[0026] A drive member can be provided for rotating the container around one axis or around two mutually perpendicular axes.

[0027] An agitator or mixer member may be placed in the container, that is rotatable about a mixer axis, and a drive member coupled to the agitator or mixer member for driving it in rotation about the mixer axis.

[0028] An embodiment of a system according to the disclosure may comprise a transducer coupled to a wall part of the container and a driver connected to the transducer for controlling the transducer to impart vibrations to the container wall in a frequency range of 2-20kHz.

[0029] The system can comprise a separator for separating silicate, magnesium carbonate and metal material from the suspension. The separator may be a filtering and / or drying station. Brief Description of the Drawings

[0030] Some embodiments of a method and system according to the disclosure will, by way of non-limiting example, be explained in detail with reference to the accompanying drawings. In the drawings:

[0031] Fig. 1 shows a schematic overview of a system according to the disclosure,

[0032] Fig. 2 shows a schematic overview of a reactor for use in a system according to the disclosure,

[0033] Fig. 3 shows a first set-up of an experiment illustrating carbon capture by agitated olivine particulate material,

[0034] Fig. 4 shows a second set-up comprising a stirring member,

[0035] Fig. 5 shows an embodiment with an open container having a bottom connected to a transducer operating at audio frequencies, and

[0036] Figs. 6a and 6b show patterns in the olivine particulate material and the carbonate reaction product, caused by the vibrations of the transducer of Fig. 5.

[0037] Detailed description

[0038] Fig. 1 shows a system 1 for accelerated mineralization of particulate metal silicate material, such as olivine, comprising a reactor 2 having a wall 3 that encloses a reactor volume 4.

[0039] A water supply 5 is connected to an inlet 7, such as a spray nozzle, for supplying water, in particular demineralized water, to the reactor volume 4. A supply vessel 8, comprising particulate metal silicate material, is connected to the reactor 2. The particulate material in the supply vessel 8 can be in a grained or in a powdered form.

[0040] An air supply 10, such as a fan or a compressor, is connected to a diffusor 12 inside the reactor 2, and supplies ambient air, containing carbon dioxide substantially at ambient pressure to the particulate material in the reactor 2. An agitating device, such as a stirring mechanism 15, comprises a mixing device 16 and a drive motor 18 for rotating the mixing device 16 about its axis 17. By action of the mixing device 16, the particulate material forms a suspension in the water in the rector volume 3.

[0041] A control unit 20 is connected to one or more sensors 21 that record the temperature and the pressure inside the reactor 2. On the basis of the temperature and pressure signals, the control unit 20 controls a heating / cooling unit 22 and the air supply 10 to maintain the temperature and pressure in the reactor volume 4 at the required set point values, such as for instance 20°C at 100 kPa.

[0042] A transducer 25 is coupled to a bottom 26 of the reactor 2 for providing vibrations in the frequency range of 2kHz-20kHz. A controller 27 is coupled to the transducer 25 for controlling the frequency and amplitude of the vibrations. In one embodiment, the transducer 25 comprises an electromagnetic coil and a membrane that is oscillated by the coils, for instance an audio speaker. By the vibrations of the wall 26, the particles in the reactor volume 3 are brought in abrasive mutual contact. By rubbing against each other, the reaction surface of the particles is cleaned and the reaction rate of the particles with carbon dioxide is accelerated.

[0043] In an alternative embodiment, the transducer 25 may be placed inside the reactor volume 4 and is an ultrasonic transducer producing vibrations in the frequency range of 20kHz- 1 GHz, for instance about 20kHz- 40 kHz.

[0044] A discharge section 30 is connected to the reactor 2 for removing the reaction products that may comprise a magnesium carbonate and silicate. In the section 30, which may comprise a filter or a drying tower for the removal of water, the reaction product is dried and a metal carbonate, such as magnesium carbonate, is produced.

[0045] Figure 2 shows an embodiment of a reactor 2, specifically designed for the accelerated mineralization of olivine and having a drive member 33 for rotating the reactor 2 about a horizontal axis L. The reactor 2 comprises a gas inlet 34 for the admission of ambient air, containing carbon dioxide. The stirring mechanism 15 comprises mixing device 16 having mixing rings 31, 32. The rector 2 forms a sealed chamber that is capable of containing olivine and reactants under controlled conditions.

[0046] A monitoring system comprises sensors 21 for measuring the temperature, pressure, carbon dioxide concentration and other relevant parameters.

[0047] Through a port 34, carbon dioxide gas is admitted in the reactor 2. A port 35 is provided for introducing water and reactants into the chamber. Via a valve 36, an excess pressure can be relieved by venting.

[0048] A door 40 is provided in the reactor wall for loading of olivine and for removal of carbonate reaction products from the reactor volume 4.

[0049] A temperature control mechanism 22, that can comprise a coil, and a pressure control mechanism 37 are placed in the reactor volume 4. The control unit 20 is adapted for regulating and maintaining optimal temperature and pressure conditions for the mineralization process.

[0050] Via an outlet / drainage port 41, reaction products such as carbonates, water or other effluent can be removed from the reactor 2.

[0051] Operation

[0052] First olivine, in fine grained or in powdered form, is loaded into an olivine reservoir within the chamber 4.

[0053] Then carbon dioxide and the other reactants are introduced and controlled into the chamber 4 through the port 34 and the reactant inlet 35.

[0054] Next, he temperature and pressure within the chamber are regulated by control unit 20 to levels for optimal olivine carbonation.

[0055] The stirring mechanism 15 and the drive 33 are activated to promote continuous mixing of olivine and reactants.

[0056] The accelerated mineralization process occurs within the reactor 2, resulting in the formation of stable carbonates that are unloaded via the door 40. The method and reactor provide for accelerated carbon sequestration, and the system significantly increases the rate of olivine mineralization, leading to faster and permanent carbon dioxide removal from the atmosphere.

[0057] By optimizing conditions such as temperature, pressure, and mixing, the system ensures a high carbonation efficiency.

[0058] The system design allows for scalability, from small-scale laboratory units to large industrial systems.

[0059] Figure 3 shows an experimental set-up for measuring the reaction rate of carbon dioxide in air with an olivine suspension in water, or wetted olivine particles at ambient conditions. A closed container 50 containing ambient air, comprises a reservoir 51 with at its bottom a first air diffusor 52 having a spherical shape of a diameter of 5 cm and a pair of second air diffusors 53 of cuboid shape of a height of 5 cm and short sides of 5 cm. The container 50 is of the type Lock & Lock HPL 886 having a volume of 10 Liters. An air pump 54 of 45 Watt, 130 gallon / hr, circulates ambient air from the container 50 via the air diffusors 52, 53 through a mixture 55 of olivine particulate material from Green Sands, Olivine sand 0.2 / 0.9 mm, art. No 350296 and water. A CO2 meter 56 of Dioxcare determines the ppm content of CO2 in the gas present in the container 50 over time.

[0060] It was found that:

[0061] 1. When adding 400 g H2O to 500 g olivine in the set-up of figure 3, at a temperature of 14°C -17°C, the CO2 concentration was found to drop from 426 ppm to 264 ppm in one hour.

[0062] 2. When adding 400g H2O to 500 g olivine in the presence of 0.1 ml organic acid (vinegar) in the set-up of figure 3, at a temperature of 15°C -17°C, the CO2 concentration was found not to be significantly lower after one hour. It was found that when instead of adding an organic acid to the water, an alkahne material was combined with the olivine-water mixture, a surprising increase in reaction rate was observed.

[0063] 3. When adding 400 g H2O to 500 g olivine in the set-up of figure 3, using distilled water, at a temperature of 12°C -17°C, the CO2 concentration was found to drop from 412 ppm to 58 ppm in one hour.

[0064] It was found that the reaction rate is strongly accelerated by a demineralization step of the water with which the metal silicate is contacted.

[0065] 4. In this experiment 850 g H2O was added to 650 g olivine in a container. The container was closed with a lid, onto which the CO2 meter was attached, and the closed container was placed onto an active triangle sanding device for causing vibrations by shaking the container with the wetted olivine particles at a temperature of 13°C -19°C. The CO2 concentration was found to drop from 413 ppm to 318 ppm in 2 hours.

[0066] The abrasion of the olivine particles against one another cleans the surface of carbonate reaction products that formed on the surface of the particles and hence maintains a high reaction rate.

[0067] 5. A container was filled with 500 g distilled water and 500g olivine particles. The mixture was stirred with a spoon at start, after which the stationary container was closed with a lid, onto which the CO2 meter was attached. The temperature was 19°C -20°C. The CO2 concentration was found to drop from 628 ppm to 264 ppm in three hours.

[0068] In a set-up shown in figure 4, the cuboid air diffusers 51 have been placed in a vertical position. A magnetic stirring bar 61 of the type Labfish 200- 1800 RPM is placed in the container 51. The stirring bar 61 is rotated by magnetic actuator 60 of a diameter of 30 mm. When adding 600 g H2O to 350 g olivine, at a temperature of 17°C -21°C, the spinning magnetic bar keeps the particles in a suspension, preventing them from settling down on the bottom of the container 51. The CO2 concentration was found to drop from 487 ppm to 326 ppm in one hour.

[0069] Fig. 5 shows an embodiment of an open reservoir 60 containing water and metal silicate particles. A transducer 61 is connected to the bottom and a controller 62 energizes the transducer 61 such that vibrations are passed to the bottom 63 of the reservoir. In this example, the vibrations are in the audio frequency range of 2-20 kHz and the transducer 61 comprises a deep bass speaker. As shown in figures 6a and 6b, the dark colored olivine particles in the water are agitated on the surface of the bottom and different geometric patterns emerge, depending on the frequencies of the transducer 61. When reacting with CO2, a light-colored inert magnesium carbonate is formed. The abrasion of the particles that collide with each other, continuously cleans the particle surface, and maintains a high reaction rate, allowing new CO2 to react with a continually refreshed interface.

Claims

Claims1. Method of reacting carbon dioxide with a metal silicate, preferably a nesosilicate material such as olivine comprising:- placing metal silicate particulate material in a container having a container wall, with water in a bed or in a suspension in the water, and -agitating the particulate material.

2. Method according to claim 1, wherein the container wall is bounding a reactor volume, the method comprising feeding an air stream at or near ambient pressure, into the container and contacting the metal silicate particles in the bed or in a suspension and maintaining the metal silicate particles at a temperature below 25 °C.

3. Method according to claim 1 or 2, the water comprising demineralized water or de-ionized water having a conductivity below 50 micro S / cm, preferably below 5 micro S / cm.

4. Method according to any of claims 1- 3, the particulate material being agitated via the air stream that is blown into the container via a diffusor.

5. Method according to any of claim 1-4, the particulate material being agitated by vibrating at least a part of the wall of the container.

6. Method according to claim 5, comprising providing vibrations to the particulate material in a frequency range of 20 kHz - 1 GHz, preferably in a range of 20-40KHz.

7. Method according to claim 5, the container comprising a substantially flat bottom wall, a transducer being coupled to the bottom wall for providingvibrations with a frequency in a range of 2-20kH, preferably in a frequency range of 50 Hz to 100 Hz.

8. Method according to any of the preceding claims, comprising adding an alkaline material to the water.

9. Method according to any of the preceding claims, the container comprising an air inlet and at least one diffusor located in the container, connected to the air inlet.

10. Method according to any of the preceding claims, comprising adding a peptide material.

11. Method according to claim 10, the peptide material comprising glycerine.

12. System for reacting carbon dioxide with a metal silicate, preferably a nesosilicate material such as olivine comprising: a container having a container wall, a water supply, the container being adapted for containing particulate metal silicate material a bed or in a suspension in the water, and agitating means for providing a reciprocating movement of the container, a vibrating movement of a part of the container wall or providing an agitating movement by contacting the particulate material in the container.

13. System according to claim 12, the water supply comprising demineralized or de-ionized water having a conductivity below 50 microS / cm, preferably below 5 micro S / cm.

14. System according to claim 12 or 13, the container wall bounding a reactor volume, the system comprising an air supply for blowing air into the reactor volume via a diffusor.

15. System according to claim 14, the air supply being adapted for feeding an air stream at or near ambient pressure, into the container.

16. System according to any of claims 12-15, comprising a temperature control means arranged for maintaining the temperature of the metal silicate particles at a temperature below 25 °C.

17. System according to any of claims 12-16, comprising a drive member for rotating the container around one axis or around two mutually perpendicular axes.

18. System according to any of claims 12-17, comprising an agitator or mixer member placed in the container, that is rotatable about a mixer axis, and a drive member coupled to the agitator or mixer member for driving it in rotation about the mixer axis.

19. System according to any of claims 12-18, comprising a transducer coupled to a wall part of the container and a driver connected to the transducer for controlling the transducer to impart vibrations to the container wall in a frequency range of 2-20kHz.

20. System according to any of claims 12-19, comprising a separator for separating silicate, magnesium carbonate and metal material from the suspension.

21. System according to claim 20, the separator comprising a filtering and / or drying station.

Images