USE OF CO2-CONTAINING GASEOUS EFFLUENT

Abstract

A method for the use of a gaseous effluent containing a CO.sub.2 gas fraction and a non-CO.sub.2 gas fraction, including at a first location: providing liquid nitrogen at a temperature less than −196° C., and causing the gaseous effluent to contact the liquid nitrogen to as to capture at least part of the CO.sub.2 present in the CO.sub.2 gas fraction as a mixture of CO.sub.2 particles and liquid nitrogen. Conveying at least part of the mixture to a second location, and at the second location, bringing the mixture into contact with one or more ingredients of a wet concrete before and/or during and/or after the wet concrete is prepared by blending the ingredients of the wet concrete in a blender, so that the mixture extracts heat from said one or more ingredients of the wet concrete, and CO.sub.2 from the mixture partially carbonates Ca-compounds present in the wet concrete.

Claims

1-15. (canceled)

16. A method for the use of a gaseous effluent containing a CO.sub.2 gas fraction and a non-CO.sub.2 gas fraction, the method comprising: (a) at a first location: providing liquid nitrogen at a temperature not greater than −196° C., causing the gaseous effluent to contact the liquid nitrogen so as to as to capture at least part of the CO.sub.2 present in the CO.sub.2 gas fraction as a mixture of CO.sub.2 particles and liquid nitrogen, (b) conveying at least part of the mixture to a second location, and (c) at the second location, bringing the mixture into contact with one or more ingredients of a wet concrete before and/or during and/or after the wet concrete is prepared by blending the ingredients of the wet concrete in a blender, so that the mixture extracts heat from said one or more ingredients of the wet concrete, and CO.sub.2 from the mixture partially carbonates Ca-compounds present in the wet concrete.

17. The method according to claim 16, whereby, at the second location, the mixture is brought into contact with the wet concrete after the blending step.

18. The method according to claim 16, whereby the mixture is brought into contact with the wet concrete during agitation of the wet concrete in the blender or in a mixer to which the wet concrete prepared in the blender is transferred.

19. The method according to claim 16, whereby the CO.sub.2 gas fraction constitutes from 7 to 100% vol of the gaseous effluent.

20. The method according to claim 16, whereby the gaseous effluent is subjected to a cooling step before it contacts the liquid nitrogen.

21. The method according to claim 20, whereby thermal energy is recovered from the gaseous effluent during the cooling step and whereby at least part of said recovered thermal energy is used as a heat source in a heating process, as an energy source for the production of mechanical energy or as an energy source for the production or electrical energy.

22. The method according to claim 16, whereby the gaseous effluent is caused to contact the liquid nitrogen until the mixture presents a CO.sub.2-particle content which is equal to or greater than a predetermined minimum CO.sub.2-particle content.

23. The method according to claim 16, whereby the CO.sub.2-particle content of the at least part of the mixture is adjusted before said at least part of the mixture is brought into contact with the wet concrete.

24. The method according to claim 16, whereby the conveying of the mixture includes transport of the mixture in a mobile cryogenic reservoir.

25. The method according to claim 16, whereby the mixture is brought into contact with the one or more ingredients of the wet concrete in a mixer, in the blender in which the wet concrete is prepared and/or in a mixer to which the wet concrete prepared in the blender is transferred.

26. The method according to claim 25, whereby the mixer is a rotating drum mixer of a concrete mixer truck.

27. The method according to claim 16, whereby the second location is situated: a site where the wet concrete is prepared in the blender, at a site where the wet concrete is cast, a site where the prepared wet concrete is introduced into a mixer, and/or at an intermediate site between a site where the wet concrete is prepared and a site where the wet concrete is cast.

28. The method according to claim 16, whereby the gaseous effluent comprises or consists of combustion gases.

29. The method according to claim 16, whereby part of the liquid nitrogen evaporates during step (a) and whereby the evaporated nitrogen is utilized at the first location.

30. The method according to claim 16, whereby: step (a) is performed at multiple first locations, the mixtures obtained at said multiple first locations are conveyed to a third location where said mixtures are combined to form a final mixture of solid-CO.sub.2-particles and liquid nitrogen, the final mixture is transported to a mixer in which wet concrete is mixed, and the final mixture is introduced into the mixer and brought into contact with the wet concrete in the mixer, thereby causing the wet concrete to be cooled and partially carbonated.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0087] For a further understanding of the nature and objects for the present invention, reference should be made to the following detailed description, taken in conjunction with the accompanying drawings, in which like elements are given the same or analogous reference numbers and wherein:

[0088] FIG. 1 is a schematic representation of an embodiment of the method in accordance with the invention, whereby identical reference numbers refer to the same or similar features in the figure.

[0089] FIG. 2 is a schematic representation of an embodiment of the method in accordance with the invention, whereby identical reference numbers refer to the same or similar features in the figure.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0090] CO.sub.2-containing gaseous effluent 10 is generated in a range of processes 11, 12, 13, 14, whereby 11 and 12 are, for example, two non-ferrous metal melting furnaces, 13 is a boiler, an anaerobic digestion plant for biomass production or a chemical process producing a CO.sub.2-containing gaseous effluent and 14 is a cement production plant.

[0091] In installations 21, 22 and 23 (corresponding to three distinct first locations), the CO.sub.2-containing gaseous effluents 10 of the different processes 11, 12, 13 and 14 are brought into contact with cryogenic liquid nitrogen 20 in such a way that at least part of the CO.sub.2 present in said gaseous effluents desublimates and that a mixture 25 of supercooled CO.sub.2 particles and liquid nitrogen is obtained. For this purpose, any of the desublimation processes mentioned earlier may be used.

[0092] As gaseous effluent 10 of process 13 is obtained at substantially ambient temperatures, it is treated directly in installation 22. The gaseous effluents 10 of processes 11, 12 and 14 being generated at significantly higher temperatures, they are first cooled in heat recovery systems 15 before being brought into contact with the liquid nitrogen 20. The heat recovered by heat recovery systems 15 is thereafter utilized for heating or for the generation of mechanical or electrical energy. Gaseous effluent 10 of cement production plant 14 is treated in installation 23, while the gaseous effluents 10 of processes 11 and 12 are treated together in a same installation 21, i.e, at a same first location.

[0093] When mixtures with at least a predetermined minimum solid CO.sub.2 content are obtained in installations 21, 22 and 23 (whereby the minimum CO.sub.2 content of the respective installations may be the same or different), at least part of the mixture 25 is removed from the corresponding installations 21, 22 and 23 and new liquid nitrogen 20 is added to the installation for the treatment of further amounts of CO.sub.2-containing gaseous effluent 10.

[0094] Step (a) of the method according to the invention may thus be performed as a semi-batch process. Step (a) may also be performed as a batch process, whereby the totality of the obtained mixture is removed from the installation 21, 22 or 23 and replaced with a new batch of liquid nitrogen. Similarly, step (a) may also be performed as a continuous process, whereby part of the obtained mixture is continuously removed and replaced with new liquid nitrogen. As shown in FIG. 1, the mixtures 25 of installations 21 and 22 are combined in reservoir 30 so that a mixture 35 of solid CO.sub.2 particles and liquid nitrogen with a specific desired CO.sub.2-particle content is obtained. The corresponding third location, where reservoir 30 is located, may be the location (first location) where one of the installations 21 and 22 is located, and to which at least part of the mixture obtained in the other of installations 21 and 22 is conveyed. Alternatively, reservoir 30 may be located at a third location which is different from the locations (first locations) where installations 21 and 22 are located, such as a central collection site to which the mixtures obtained from different first sites are collected. Further ingredients may also be added to the mixture in reservoir 30. If necessary, additional liquid nitrogen 31 may be added to reduce the CO.sub.2-particle content. Furthermore, a suspending agent 32 may be added so as to obtain a suspension 35 with substantially even distribution of the CO.sub.2 particles in the mixture. Thereto, reservoir 30 may be provided with an agitator or agitator system (not shown).

[0095] Cement 100 produced in cement production plant 14 is mixed with sand (fine granulate) 101 and gravel (coarse granulate) 102 in silo 100. Mixture 25 from installation 23 is conveyed to silo 102 by means of a cryogenic conduit and is then added to these solid ingredients, which are thereby cooled. When the temperature of the solid ingredients 100, 101, 102 has dropped to a sufficiently low value, the solid ingredients 100, 101, 102 are introduced, together with the added mixture 25 from installation 23, to blender 120 where process water 121 is further added and blending proceeds until wet concrete 125 is obtained. The temperature of said wet concrete 125 is kept low by means of mixture 25. In addition, the CO.sub.2 content of said mixture 25 causes partial carbonation of the wet concrete in the blender 120.

[0096] To the extent that added mixture 25 contains H.sub.2O ice crystals, the amount of process water 121 added may be adjusted.

[0097] Instead of or in combination with the cooling of one or more of the solid ingredients 100, 101 and 102 in silo 100 before process water 121 is added thereto, it is also possible to cool and partially carbonate the wet concrete during the blending of said ingredients in blender 120, i.e. during the preparation of the wet concrete itself.

[0098] Part of the wet concrete 125 produced in blender 120 is sent to a plant 130 in which concrete parts, such as prefabricated concrete construction elements, are produced.

[0099] Mixture 35 from reservoir 30 is divided over a number of transportable cryogenic reservoirs (not shown).

[0100] Part of the wet concrete 125 produced in blender 120 is introduced in the rotating drum of a concrete transport truck 140. Friction caused by the rotation of said drum and/or convective and radiative ambient heat, causes the wet concrete in the rotating drum to heat up. However, one of the transportable cryogenic reservoirs is available at the site where the wet concrete 125 is loaded on truck 140. In order to keep the wet concrete 125 in the truck 140 cool, and cause partial carbonation of said wet concrete 125, a controlled amount of mixture 35 can be injected into the rotating drum in contact with the wet concrete 125.

[0101] Truck 140 is then used to transport the wet concrete 125 to the construction site 150. where it will be cast. When the distance over which the wet concrete 125 is to be transported is such that the temperature of the wet concrete 125 may rise unacceptably en route, further mixture 35, supplied in a second cryogenic reservoir, may be injected in the rotary drum of truck 140 in contact with the wet concrete 125 at an intermediate location 140a between the site where the wet concrete 125 was loaded on truck 140 before travelling on towards construction site 150 and construction site 150 itself.

[0102] As the setting of the wet concrete is an exothermal reaction and the temperature of the setting concrete must be kept within limits to prevent faults in the set concrete, cooling in combination with partial carbonation, may be useful immediately before the wet concrete 125 is cast. Thereto, a cryogenic reservoir with mixture 35 is available on construction site 150. Before the concrete is cast, the wet concrete 125 can be put into contact with mixture 35, whereby the wet concrete 125 is cooled and partially carbonated at construction site 150 before the wet concrete 125 is cast.

[0103] In the embodiment illustrated in FIG. 2, blender 120 is located at a distance from cement production plant 14 and the cement 100 produced in plant 14 is transported from cement plant 14 to blender 110, for example in cement bags which shield the cement against humidity during storage and transport, or in bulk, for example, in tank trucks, train carriages or ships. In addition, the mixture 25 of solid CO.sub.2 particles and liquid nitrogen from installation 23 at cement plant 14 is conveyed to reservoir 30, where it is combined with the mixtures 25 from the other installations 21 and 22 in order to obtain mixture 35 with the specific desired CO.sub.2-particle content. From reservoir 30, the required quantities of mixture 35 are transported in moveable cryogenic reservoirs, for example cryogenic tank trucks or rail carriages, to the one or more locations and equipment where mixture 35 is to be brought into contact with one or more ingredients of the wet concrete, as the case may be, the wet concrete itself. Possible such installations/locations are: silo 110, in which the dry ingredients 100, 101 and 102 are combined, blender 120, in which the wet concrete is prepared in that process water is added 121 is added to and blended with the dry ingredients 100, 101 and 102 to produce wet concrete 125, concrete transport truck 140 at the location where the rotating drum of truck 140 is filled with wet concrete 125 from blender 120, at the construction site 150, where the wet concrete 125 will be cast, and concrete transport truck 140 at an intermediate location 140a between the filling of the truck and its arrival at the construction site 150.

[0104] When, in the different steps described above, partial carbonation of the wet concrete takes place, CO.sub.2 becomes chemically bound to Ca-elements in the wet concrete and ends up effectively sequestered in the final set concrete element.

[0105] In the above examples, different possibilities for bringing the wet concrete or ingredients thereof in contact with the mixture of solid CO.sub.2 particles and liquid nitrogen have been described. It will be appreciated that, generally speaking, not all of these steps will be required to achieve the required cooling and partial carbonation of the wet concrete. Only one or only a limited number of such steps may in practice be required, depending on the circumstances. Said circumstances including environmental temperatures and heat radiation, the travel time of the wet concrete and the size of the concrete elements to be cast. When during the process chain from the preparation of the wet concrete to the casting of the wet concrete, one or more ingredients of the wet concrete 125 are brought into contact with the mixture 25, 35 at multiple occasions, care is taken to ensure that suitable levels of cooling and partial carbonation are achieved. For example, in the case of a single contact between the mixture and one or more ingredients of the wet concrete 125, a mixture with a higher CO.sub.2-particle content may be used compared to when one or more ingredients of the wet concrete 125 are repeatedly brought into contact with the mixture 25, 35, thereby avoiding excessive carbonation, while still ensuring adequate cooling.

[0106] It is also possible to combine the method according to the invention with further treatments of the wet concrete, for example with additional cooling steps by means other than contact with a mixture of solid a mixture of CO.sub.2 particles and liquid nitrogen.

[0107] It will be understood that many additional changes in the details, materials, steps and arrangement of parts, which have been herein described in order to explain the nature of the invention, may be made by those skilled in the art within the principle and scope of the invention as expressed in the appended claims. Thus, the present invention is not intended to be limited to the specific embodiments in the examples given above.