System, apparatus and method for carbon dioxide sequestration
View Patent ↗A carbon dioxide sequestration process includes the following steps. In a first stage, a slurry of a metal silicate rock is mixed with ammonia so as to produce a ammonia/water/metal silicate slurry. In a second stage, the process includes scrubbing a gas stream containing carbon dioxide with the solution from the first stage to thereby absorb the carbon dioxide into a reactive slurry. In a third stage, the reactive slurry from the second stage is passed through a reactor that is controlled so as to promote the reaction between the carbon dioxide and the metal silicate to thereby produce a metal carbonate.
1. A carbon dioxide sequestration process including the steps of:
(i) providing a slurry comprising metal silicate rock;
(ii) in a first stage, mixing the slurry of metal silicate rock with ammonia so as to produce an ammonia/water/metal silicate slurry;
(iii) in a second stage, scrubbing a gas stream containing carbon dioxide with the slurry from (ii) to thereby absorb the carbon dioxide into the slurry so as to form a reactive slurry;
(iv) in a third stage, passing the reactive slurry from (iii) through a reactor that is controlled so as to promote a reaction between the carbon dioxide and the metal silicate and produce a metal carbonate; and
(v) recovering ammonia resulting from the reaction stage (iv) and recycling it to the first stage wherein the ammonia recovery is effected in a recovery vessel which is pressurized to facilitate the recovery of ammonia in liquid form.
2. A process in accordance with claim 1 , wherein in step (ii), pressurized liquid ammonia is charged into the metal silicate slurry in such a manner that the liquid ammonia partially flashes to a vapors to produce the ammonia/water/metal silicate slurry.
3. A process in accordance with claim 1 , wherein the step of scrubbing the gas stream comprises exposing the carbon dioxide-containing gas stream into a spray of the slurry.
4. A process in accordance with claim 1 , wherein controlling the reactor comprises elevating at least one of a pressure and temperature of the reactor so as to enhance the reaction between the carbon dioxide and the metal silicate.
5. A process in accordance with claim 1 , wherein the reactor is a pipeline.
6. A process in accordance with claim 5 , wherein the pipeline comprises multiple flow paths and wherein the reaction takes place along the length of one of the flow paths.
7. A process in accordance with claim 6 , wherein another of the flow paths utilized to supply the metal silicate slurry from a source.
8. A process in accordance with claim 7 , comprising the further step of exchanging at least one of pressure and heat between the reactive slurry and the metal silicate slurry before and/or after the pipeline.
9. A process in accordance with claim 1 , wherein the reactor is a chamber located underground.
10. A process in accordance with claim 9 , wherein the chamber is located at a depth that provides sufficient pressure to enhance the reaction between the carbon dioxide and the metal silicate.
11. A process in accordance with claim 1 , comprising the further step of introducing an alkali to the metal carbonate product resulting from the reaction stage (iv) prior to carrying out the ammonia recovery step.
12. A process in accordance with claim 1 , wherein the ammonia is recovered as both a liquid and a gas, with the liquid being converted partially to a vapour for recycling in the first stage and the gas being extracted, condensed and mixed with the metal silicate before it is supplied in the first stage.
13. A process in accordance with claim 1 , wherein the recovery vessel is in use located at a depth sufficient for achieving the pressure to recover the ammonia in liquid form.
14. A process in accordance with claim 1 , comprising the further step of grinding a metal silicate rock to produce the metal silicate slurry.
15. A process in accordance with claim 14 , wherein the metal silicate slurry comprises ground metal silicate.
16. A process in accordance with claim 1 , wherein the metal silicate is a magnesium-rich silicate comprised of a serpentine- and/or olivine- and/or pyroxene-rich mineral.
17. A process in accordance with claim 1 , wherein the slurry of metal silicate rock is chilled prior to passing the slurry to the second stage.
18. An ammonia absorption process in a carbon dioxide sequestration process, the ammonia absorption process comprising the steps of:
(i) producing a slurry of metal silicate rock mixed with ammonia so as to produce an ammonia/water/metal silicate slurry;
(ii) provide pressurized ammonia in liquid form;
(iii) expanding the pressurized ammonia in liquid form in an evaporator stage so as to provide a cooling effect in that stage; and
(iv) passing the ammonia/water/metal silicate slurry through the evaporator stage so as to produce a chilled ammonia/water/metal silicate slurry.
19. The ammonia absorption process in accordance with claim 18 , comprising the further step of providing the chilled ammonia/water/metal silicate slurry to a scrubbing stage that comprises a scrubbing chamber, wherein a gas stream containing carbon dioxide is scrubbed with the chilled ammonia/water/metal silicate slurry to thereby absorb the carbon dioxide into a reactive slurry.
20. The ammonia absorption process in accordance with claim 19 , comprising the further steps of: passing reactive slurry through the evaporator stage; and recirculation of the reactive slurry through the scrubbing chamber; wherein; the evaporator stage is carried out in an evaporation chamber.