DK201400177U1 - A system for capturing co2 from a co2-containing gas - Google Patents

Abstract

MGL

Description

PROCESS POR 002 CAPTURE USING MICRO-PARTICLES COMPRISING '

Biocatalysts

FIELD OF THE INVENTION

The present invention relates generally to C0S capture and more particularly to a process for CQ2 capture using micro-particles comprising biosataiysis,

BACKGROUND

Increasingly dire warnings of the dangers of climate change by the world's scientific community combined with greater public awareness and concern over the issue have prompted increased momentum towards global regulation aimed at reducing man-made greenhouse gas (GHOs) emissions, most notably carbon dioxide. Ultimately, a significant cut in North American and global CG2 emissions will require reductions from the-etectrieiiy production sector, the single largest source of CQ2 worldwide. According to the International Energy Agency's (IEA) GHG Program, as of 2006 there were nearly 5,000 fossil fuel power plants worldwide generating nearly 11 billion tonnes of € 0¾ representing nearly 40% of total global anthropogenic C02 emissions. Of these emissions from the power generation sector, 81% were from coal medium plants. Although the long-term agenda advocated by governments is replacement of fossil fuel generation by renewables, growing energy demand, combined 'with :: the. enormous dependence on fossil generation in the near to medium term dictates that this fossil base remains operational. Thus, to implement an effective GHG ..reduction system will require that the C02 emissions generated by this sector be mitigated, with carbon capture and storage (CCS) providing one of the best Known solutions.

The CCS process removes C02 from a C02 containing flue gas, enables production of a highly concentrated COs gas stream which is compressed and transported to a sequestration site. This site may charge a depleted sitHeld or a saline aquifer. Sequestration in ocean and mineral carbon atlons are: two alternative ways to sequester that are in the research phase. Captured COa can also be used for enhanced oil recovery.

Current technologies for COg capture are based primarily on the use of amine solutions which are circulated through two main distinct units: an absorption tower coupled to a desorption (or stripping) tower.

Siocataiysts have been used for C02 absorption applications. For example, 0 (¾ transformation may be catalysed by the enzyme carbonic anhydrase as follows: α% + »so ϊϊϋϊϋ '" ίϊί ^ ". + Mol

Under optimum conditions, the: catalyzed turnover rate of this reaction may reach 1 x 10s m ol ecu i e s / secon d.

There are some known ways of providing carbonic anhydrase in C02 capture reactors. One way is by immobilizing the enzyme on a solid packing material! in a packed tower reactor. Another way is by providing the enzyme in a soluble state in a solution within or flowing through a reactor, Both of those methods provide benefits but also some limitations. Enzyme immobilized on a solid packing material limits the enzyme benefit since it has a limited presence in the thin reactive liquid film at the gas-liquid interface which has a thickness of about 10 pm; enzyme on packing is several millimeters from the gas-liquid: interface. Soluble enzyme brings the optimal enzyme imped, however it cannot be easily separated from the solution and if the enzyme is not robust to intense conditions such as those used in desorption operations, it will be. denatured and the process will require high levels of continuous enzyme replacement.

There is a need for a technology that overcomes some of these problems and challenges of the known techniques for providing biocatalysts such as carbonic anhydrase in COg capture reactors. SUMMARY OF THE INVENTION

The present invention responds to the above mentioned need by providing a process for C02 capture using micro-particles comprising blocks,

More particularly, the present invention provides a process for capturing CO * from a COs-confining gas comprising contacting the CO? -Containing gas with an absorption mixture within a packed: reactor, the absorption mixture comprising a liquid solution and micro-paries, the micro-particles comprising a support material and biocatalysts supported by the support material and being sized and provided in a concentration such that the absorption mixture flows through the packed reactor and that the micro-particles are carried with the liquid solution to promote dissolution and transformation of COa into bicarbonate and hydrogen ions, thereby producing a COs> depleted gas and an ion-rich mixture comprising: the micro-particles,

In one options} aspect, the process involves removing the mlao-pads from the ion-rich mixture to produce an ion-rich solution. In another optional aspect, the removal of the micro-particles is performed by filtration mechanism, magnetic separation, centrifugation, cyclone, sedimentation or a combination thereof, in another optional aspect, the process comprises performing desorption or mineral carbonation on the ion-rich, solution to produce an ion-depleted .solution. The ion-hob mixture may comprise precipitates and the precipitates may be removed from the ion-rich mixture prior to performing the desorption or the mineral carbonation.

In another optional aspect, the process involves adding an amount of the microparticles to the ion-depleted solution before recycling the ion-depleted solution to further contact the C02 ~ e »ntaining gas.

In another optional aspect, the process comprises feeding the ion-rich mixture Into a desorption reactor, the micro-particles being stabilized by the support material and being sheathed and provided in a concentration in the desorption reactor such that the microparticles are carried with the ion -rich mixture to promote transformation of the bicarbonate and hydrogen ions into CO? gas and water, thereby producing a C02 gas stream and the ion-depleted solution.

In another optional aspect, the micro-particles may be sized to facilitate separation of the micro-particles from the son-rich mixture. For Instance, the micro-particles may be sized to have a diameter above about 1 pm or above about 5 pm.

In another optional aspect, the micro-particles may be sized to have a catalytic surface area: comprising the biocatalysts having an activity density such as to provide an activity level equivalent to a corresponding activity level of soluble hiocatalysts above about 0.05 g biocatalyst / 1, optionally between about D OS g biocatalyst / 1 and about 2 g biocatalyst / L, and preferably between about £ i OS g biocatalyst / L and: about 0.5 g biocatalyst / 1, for the case of biocatalysts having a minimum activity of about 280 WA unlls / rog, in another optional aspect, the absorption mixture and the form of a reactive liquid film having a thiohness and the micro-particles are sized so as to be within an order of magnitude of the thickness of the reactive liquid film, In another optional aspect, the absorption mixture and the CO2 form a reactive liquid film having a thickness and the micro-portions are -sized so as to be smaller than the thickness of the reactive liquid film. The thickness of the reactive liquid film may be about 10 pm.

In another optional aspect, the micro-particles are sized between about 1 pm and about 100 pro.

In another optional aspect, precipitates may be formed in a tone-rich mixture and the micro-particles may be sized to be larger or heavier than the precipitates.

In another optional aspect; the micro-particles have an activity density of about 0.06 WA / mm2, optionally of about 0.6 WA / mro2 or more.

In another optional aspect, the micro-particles are provided in the absorption mixture at a maximum particle concentration of about 40% w / w. In some optional aspects, the maximum micro-particle concentration may be 35% wM \ 30% w / w , 25% w / w, 20% w / w, 15% w / w, 10% w / w, or 5% w / w, in another optional aspect, the support material is at least partially composed of nylon, cellulose, silica, silica gel, chltosan, polystyrene, polymethymimetacryiate, magnetic material, or a combination thereof. The support: may preferably be composed of nylon.

In another optional aspect, the density of the support material may be between about 0: 8 g / rnf and about 3 g / nii.

In another optional aspect, the absorption mixture comprises water and an absorption compound. The absorption compound may comprise primary, secondary and / or tertiary amines; primary, secondary and / or tertiary alkanoiaralnes; primary, secondary 'and / or tertiary amino acids; and / or carbonates. More particularly, the absorption compound may comprise piperidine, piperazine, derivatives of piperidine or piperazine which are substituted by at least one alkanol group, monoathanolamine (ΜΕΆ), 2 ~ aminp-2-methyl-1-propanol (AfyIP), 2 ~ C2-Aminoethylamino} ethanoyl: {AEE), S-Amino-S-hydroxymethyl-1,3-propanedioli (Tris), N-Methyldiefhanolamine (MDEA), Dimethylmoneethanolamina (DMMEA), Diethylmonoethanoiamine (DEMEA), Trifeepropanolamine (TIP) triethanolamine, dialkyl ether or polyalkylene glycols, dialkyl ether or dimethyl ether or polyethylene glycol, amino acids including glyelne, profine, arginine, histidine, lysine, aspartic acid, glutamic acid, methionine, serine, threonine, glutamine, cysteine, asparagine, valine, leucine, , alanine, valine, tyrosine, tryptophan, phenylalanine, and derivatives such as taurine, N.oyclohexyl 1 J-propanedlamine, M-secondary butyl glycine, N-methyl N-secondary butyl glycine,, thiophylglycine, dimethylglyoine, taurine, mephiyl-α-aminopropionic acid, Ν ~ {β ~ ethoxy) tauFsne, N'-fp-aminoothylltaursne, N-thefbyl alanine, 8-aminohexanoic acid and potassium or sodium satis of the amino acids; potassium carbonate, sodium carbonate, ammonium carbonate, promoted potassium carbonate solutions and promoted sodium carbonate solutions or promoted ammonium carbonates; or mixtures thereof, in another optional aspect, the biooatalysis are enzymes. The enzymes are preferably carbonic anhydrase. The carbonic anhydrase may be immobilized on a surface of the support material of the micro-particles, entrapped within the support material of the micro-particle, or a combination thereof, in another optional aspect, the carbonic anhydrase may also be provided as a cross-linker. linked enzyme aggregates (CLEAs) and the support materia! comprises a portion of the carbonic anhydrase and cross linker, In still another optional aspect, the carbonic anhydrase is provided as cross-linked enzyme crystals (CLECs) and the support materia! comprises a portion of the carbonic anhydrase.

In another optional aspect, the process comprises selecting a desired bioeatalytic activity level; determining a maximum, allowable particle concentration for the packed reactor; determining a total surface area required to reach the bioeatalytic activity level; determining a total volume of the micro-particles to reach the maximum; and determining a maximum size of the micro-particles to achieve the bioeatalytic activity level with the maximum allowable particle concentration.

The invention also provides a process for capturing GO ?, from a G02-cohesive gas comprising contacting the COa-containing gas with m absorption mixture comprising a liquid solution and micro-particles, the micro-particles comprising a support material! and biocatalysts supported by the support material and being sized and provided in a concentration such that the absorption mixture is pumpabie and that the micro-particles are carried with the liquid solution to promote dissolution and transformation of CDs into bicarbonate and hydrogen ions, thereby producing a GOj-dapieted gas and an ion-rich mixture comprising the: micro-partides.

In one optional aspect of this process, contacting the absorption mixture with the COr containing gas is performed in an absorption stage comprising at least one reactor selected from a packed tower, a spray tower, a fluidized bed reactor and a combination thereof. in various other options! aspects of this process:, the features mentioned in the previous paragraphs may also be used.

The invention also provides a process for desorbing 00¾ gas from an ion-rich aqueous mixture comprising bicarbonate and hydrogen sons, .comprising: providing micro-particles in the toft-rich aqueous mixture; feeding the ion-rich aqueous mixture info a desorption reactor; the micro-particles comprising a support material and biocatalysts supported and stabilized by the support material and fee steed and provided in a concentration in the desorption reactor such that the microparticles are carried with the ion-rich aqueous mixture to promote transformation of the bicarbonate and hydrogen ions Into CO * gas and water, thereby producing a COi; gas stream and an ion-depleted solution.

The present invention also provides micro-particles for introduction into a liquid solution for capturing CQg from a GOg-containing gas. The micro-particles may have optional features and uses as described for the optional aspects of the process herein,

The present invention also provides a system for capturing COa from a COs-containing gas. The system comprises an absorption unit comprising a gas Met for the CGr containing gas, a liquid inlet for providing an absorption mixture comprising a liquid solution and micro-particles comprising a support material and biocatalysts supported thereby. The system comprises a reaction chamber for allowing the micro-particles to be carried with the liquid solution to enable dissolution and transformation of GO * Into bicarbonate and hydrogen ions, thereby producing a CDg-depleted gas and an ion-rich mixture containing the micro-particles. particles. The system comprises a gas outlet for expelling the COs-deposited gas and a liquid outlet for expelling the ion ~?! Ch mixture containing the micro-particles. Optionally, the system may comprise a removal unit for removing the micro-particles from the ion-depleted mixture and producing an ion-rich solution; a regeneration unit for receiving the ion-rich solution and allowing desorption or mineral carhonation by releasing the bicarbonate ions from the ion-rich solution to produce an ion-depleted solution; and an addition unit for adding the micro-particles to the ion-depleted solution before the same is recycled back into the liquid inlet of the absorption unit The system may have optional features as described for the optional aspects of the process herein,

Managing and coordinating the size, concentration and biocatsiyfie activity of the microparticles -allows advantageous operation In C02 capture processes.

LETTER DESCRIPTION OF THE DRAWINGS

Fig. 1 is a process diagram of an embodiment of the present invention, wherein biocatalytic microparticles flow in tie absorption solution.

Fig. 2 is a process diagram of another embodiment of the present invention, wherein an absorption unit is coupled to a desorption unit and biocafalytic micro-particles flow in the absorption solution.

Fig. 3 is a schematic representation of the gas-ifcpd interface in absorption.

Fig. 4 is a graph showing evolution of residual activity of .enzyme micro-particles exposed to MDEA 2M at 40VC, illustrating stability effect.

DESCRIPTION.OF PREFERRED EMBODIMENTS

Figs 1 and 2 respectively show two different embodiments of the process and system of the present invention. It should also be understood that embodiments of the micro-particles of the present. Invention may be used in conjunction with the process and system.

In general, the process takes advantage of biocatalysts for gas scrubbing especially for COs removal from a GO 2 -containing effluent. In one embodiment, the process enables the use of immobilized biocatalysts, such as carbonic arshydrase, for 0 (¾ removal in a packed column. The carbonic anhydrase may be supported on the micro-particles within the formulation, by being directly bonded to the surface of the particle support material, entrapped inside or fixed to a porous support material matrix; entrapped inside or fixed to a porous coating material provided around a support particle which is itself porous or non-pbrous, or present as cress linked enzyme aggregates (CUsA) or cross-linked emyrne crystals (<2LEC) as the inner support material * It includes an aggregate of enzymes and any other agents that may be used in the formation of CLEAs or CLECs, such as a cross! enzymes may be provided in CLÉA or CLÉø form, which may be provided on or around a different support material which may be magnetic or not. It should be understood that a combination of the above Immobilization techniques may is used to allow the biocatalytic micro-particles to flow in the absorption solution through the reactor, e.g., through and / or around packing material of a packed column.

The present invention provides a process for capturing COafrom a COrContaining. gas. In one embodiment of the process, the first step comprises contacting the COr containing gas with an absorption mixture comprising a liquid solution and micro * particles. The micro-particles comprise a support material and biocatalysts supported thereby, The micro-particles are provided such that the absorption mixture is pumpahie. Preferably, the step of contacting the gas and liquid phases is conducted such that the micro-particles flow with the liquid solution, move within the liquid solution and move in and out of the bulk flow, to improve rapid convective mass transfer of the 00. ¾ reactant and the hydrogen and bicarbonate ion products,

This absorption step may be performed in a variety of readers. Preferably, the absorption step is performed in a packed tower reactor. It may also be done in a spray tower or another type of reactor. In the case of a packed tower, the micro-particles flow downward by flowing with the liquid solution while colliding against and ricocheting off the packing. While the bulk flow of the micro-particles follows that of the liquid solution through the reactor, the collisions cause some irsicro-parts to change direction and speed so as not to move with the local flow of the liquid solution. This movement within the liquid solution may have linear and / or spinning components and enable rapid convective mass transfer of CO? to access the Feiocatalysts on the micro-particles, in addition, the micro-particles are preferably sized (along with density and shape) to enable them to be carried with the bulk flew of the liquid solution and to be present in the thin reactive film between gas and liquid phases. It should be understood that such micro-particles may completely or partially break free of the bulk flow. Such broken-free micro-particles may have a particularly thin liquid film coating: enabling rapid penetration by CQs, These micro-particles allow the bicarbonate and hydrogen ions formed in the thin liquid film to rapidly disperse into the bulk liquid solution.

In another embodiment, the reactor may be a spray reactor. The micro-particles may be deflected or caused to move out of the bulk flow due to the cross-current, co-current or counter-current flow, incident spray nozzles, other micro-particles and pure liquid droplets, the side wails of the reactor, other objects that may be provided in reactor, etc ,, as desired, The spray reactor may be a vertical spray tower or a horizontal duct type. The spray reactor may be baffled or free of obstructions between the spray nozzles and a demister at the opposite end. It will be understood that the bulk flow of the liquid solution may be relatively large droplets or conglomerations of droplets sprayed or formed in the spray tower. The reactor is configured so that at least a film of liquid surrounds the micro-particles to avoid drying and denaturing the btocatafysts, In operation, when the micro-parleles are sprayed into such a reactor, some microparticles may be present as single free particles with a thin liquid film while others are present: as a plurality 'of particles within individual droplets, depending on the size of the inlet nozzles, the size of the micro-particles, the liquid and gas flow conditions, among other operating parameters. The thin liquid film surrounding the micro-particles allows rapid diffusion of the 00¾ to access the biocatalysts as well as liquid replacement from movement through the humid reactor and collisions with droplets and other microparticles. The reactor may be designed to have various nozzles for spraying. The microparticles used in spray reactors enable increased surface area and rapid mass transfer as the micro-particles move through the humid mist environment. The micro-particles may be sized, for example, to be carded within the absorption mixture in the firm of atomized fog. The size, density, shape or porosity of the micro-particles may be managed to help -increase surface area, Increase biocataiyst activity, ensure the btocataphysts stay moist or improve the movement of the miero-pvartides relative to the COcContalnlng gas to increase mass transfer .

In another embodiment, the reactor may be a fluidized bed reactor. The Micro-particles may be provided lh order to ftow through the fluidized bed to avoid being retained thereto.

The size of the composite micro-particles may depend on the type of reactor, the process conditions, the density and shape of the support material. The density may be chosen based on the desired catalytic activity or the separation of the micro-particles from the solution, or both. The density may be about 0.6 to about 3. g / ml. For instance, nylon supports may have a density of about 1.1, cellulose supports may have a density of about 1.6 and magnetic supports may have a density of about 2.5. The density of the micro-particles may also be selected depending on the type of separation technique used to remove the micro-particles after the absorption stage, as the case may be. For Instance, if the micro-particles are denser than water, then certain separation methods may be advantageous. The density of the micro-particles may also be selected to enhance the absorption process itself depending on the operating conditions and the type of reactor used. For example, if it is desired to avoid sinking the micro-particles may have a density similar to the density of the absorption mixture or tone-rich mixture, if desired. The effect of density will also be appreciated in light of sort of tbs examples presented herelnbeiow, The shape of the micro-particles may also be chosen based on the. rheological effects and the available surface ares of the micro-particles, as will also be appreciated In light of some of the examples presented herelnbeiow.

In one optional aspect of the present Invention, the particle concentration and particle size are managed along with the enzyme activity in a given solution. The particle concentration required to reach a given level of enzyme activity In a solution is a parameter that impacts the particle size. If the particle concentration is too high, it may result in an absorption mixture that is difficult or impossible to be pumped through a packed bed or spray reactor system. In this regard, having in the solution the same enzyme activity as 1 g / L of soluble carbonic anhydase (CA), results have demonstrated that for 350 pm polymeric micro-particles with CA fixed at their surface, with an activity density of 0 , 51 VVilbuf-Ahderson.unitimny '' (WA / mrrrt), the corresponding particle concentration is about 60% (w / w), which is too high to be pumped, in order to reduce the particle concentration below a preferred level of 80 % {w / w}, which is equivalent to 300 g / L for particles with density near 1, the 350 pm micro-particles must be either modified such that they provide a higher activity density or reduced in size. For example, given the same activity density of 0.51 uhitWA / mm2 and the same activity equivalent to 1 g / L soluble CA, using micro-particles with a diameter of 50 µm would result in a particle concentration of 90 g / L ( or 9% w / w}, a pumpable absorption mixture.More about the particle size and concentration will be discussed herelnbeiow with regard to a calculation method and the impact of various parameters, in another optional aspect of the present invention, the parttete size of The micro-partides are chosen according to the thickness of the reactive film in the given solution. The thickness of the reactive film depends on certain factors including the type of absorption solution and the gas being absorbed. absorption solutions, the reactive film has a thickness of about 10 pm.

Referring to Fig. 3, a schematic representation of the gas liquid interface in an absorption unit is. shown. In this absorption unit, the gas phase flows upward and liquid, phase downward. Mass transfer between the two'phases takes place in the gas film (thickness of dg) and the liquid film (thickness of bl). For CGS absorption, resistance to mass transfer is in the liquid phase. In conventional absorption solutions, the thickness of liquid film at the surface of the packing is several millimeters. However, the thickness of the reactive liquid film where the mass transfer and reactions between C03 and the solution take place (51}: is about 10 pm. Thus, to take the best advantage of the enzyme, it is preferably present in this reactive liquid Possible ways to achieve this are by using soluble enzyme or by using small-diameter enzyme enzymes. By comparison, enzyme immobilized to large fixed packing, which is at the surf ace of the packing material, is several millimeters away from The gas liquid interface and the reactive liquid film and its impact is thus relatively lower.

To take advantage of the effects associated with such reactive film thicknesses, the micro-particles may be sized such that the diameter is within about m of magnitude as the film thickness, preferably smaller than the film thickness, in one instance where the reactive film has a thickness of about 10 pm, the micro-particles maybe sized between about 1 pm and about 100 pm, preferably between about 1 pm and about 10 pm, still preferably about 10 pm, preferably below about 5 pm. In another embodiment, the lower limit of the micmarticle size is chosen based on the desired micro-particle separation method, such as filtration. Micro-particles of a certain size may be more easily separated from the ion-rich mixture using some separation methods while remaining narrow! enough to achieve the desired catalytic activity.

One embodiment of the process and system is shown in Fig 1 and will be described in further detail hereafter, First, the biocatalytic micro-particles are mixed in the lean absorption solution in a mixing chamber (E * 4). The lean absorption solution refers to the absorption solution characterized by a low concentration of the species to be absorbed. This solution is either fresh solution or comes from the mineral carbonafion process or the € (¾ desorption process (10). The absorption solution with biocatalytic particles (11), also referred to as the absorption mixture, is then fed to the top of a packed column (E-1) with a pump (E-7) .The packing material - (9) may be made of conventional material like polymers, metal and ceramic. The geometry of the packing may be chosen from what is commercially available It is also possible to choose or arrange the packing to promote certain deflections and collisions with the micro particles, or to avoid accumulation of the micfO particles within the reactor. For instance, the packing preferably has limited upward facing concavities to avoid the accumulation : of micro-particle® therein, Also preferably, the packing supports are much larger than the micro-particles, Also preferably, the micro-particles and packing are chosen so that the micro-particles can flow through the reactor without clo gging. Courster-currently, a C02 containing gas phase (12) is fed to the packed column (E ~ 1) and flows on, through and / or around the packing (9) from the bottom to the top of the column. The absorption solution and biocatalytic micro-particles flow on, through and / or around the packing material (9) from the top of the column to the bottom. As the absorption solution and biocatalytic micro-particles progress through the absorber, the absorption solution becomes richer In the compound being absorbed, Biocafaiytic micro-particles, present near the gas-liquid interface, enhance COs absorption by immediately catalyzing the CO? hydration reaction to produce bicarbonate ions and protons and thus maximizing the CO? concentration gradient across the interface. At the exit of the column, the rich absorption solution and biocatalytic micro-particles (13) are pumped (ES) to a particle separation unit (E ~ 3), Rich absorption solution refers to the absorption solution characterized by a concentration of absorbed compound which is higher than that of the lean solution. The separation unit may comprise a filtration unit (such as a tangential filtration unit), a centrifuge, a cyclone, a sedimentation tank or a magnetic separator and any other units or equipment known for particle or solid separation. The separation unit also enables a certain quantify of solution to be retained with the micro-particles so the particles do not dry out which can denature the biocataiysts. In one optional aspect, the quantity of retained solution enables the micro-particles to be pumped to a storage unit or directly back to a mixing chamber (E ~ 4) for addition Into the absorption unit, in another optional aspect, the microparticles with retained solution may be gravity fed into the mixing chamber (E «4), which may be enabled by performing separation above the mixing unit, for example. The separation may be conducted in continuous or in batch mode, and may be managed to ensure the proper amount of solution is retained to ensure enzyme activity. It may also be preferred that the micro-particles be provided such that they may be easily separated into any solid precipitates (eg bicarbonate precipitates) that may be entrained in the ion-rich solution, if necessary. particles (15) is then pumped (E-9) to another unit which may be a CO? desorption unit or a mineral carbonate unit - (10), Bloaafalytio micro-particles (16) are mixed with the -CO? lean absorption solution. This suspension is then fed once again to the absorption column (E-1),

In another embodiment, the absorption unit is coupled to a desorption unit as shown in further detail in Figure 2. In this embodiment, the absorption solution rich in CO? without biocatalytic micro-pads (1S) is pumped (E-9) through a heat exchanger (E-10) where it is heated and then to the desorption column (£ -11). in the desorption unit, the solution is further heated in order that the 00 * is released from the solution in a gaseous state. Because of relatively high temperature used during desorption, water also vaporizes. Part of the absorption solution {18} is directed toward a reboiler (6-1.2) where it is heated to a temperature enabling 00¾ desorption. Gaseous CDs together with water vapor are cooled down, water condenses and is fad back to the desorption unit (19), Dry gaseous C02 (20) is then directed towards a compression and transportation process for further processing. The liquid phase, containing less 00¾ and referred to as the lean absorption solution (17} is then pumped (E-14) to the heat exchanger (E-10) to be oooied down and fed to the mixing chamber (E-4) The temperature of the lean absorption solution (17) should be low enough not to denature the enzyme if present.

The biocatalysts can be supported on the support material in any of the ways described hereinabove and such micro-particles are mixed in the absorption solution and flow downward, through and / or around the packing of the packed column. Counter »Currently, the gas containing COs flows on, through and / or around the packing and contacts the absorption solution with the hiocafalyttc micro-particles.

In one optional aspect of the invention, an advantage of having Miero-parflcfcs with biocatalysts in the absorption solution is that the enzyme is brought Into close contact with the gas phase, thus maximizing the £ 2¾ concentration gradient across the gas and liquid phases and consequently the CO2 absorption rate. An advantage of this process is that the impact of immobilized biocatalysts can be greater because they are closer to the gas liquid interface. The performance is improved compared to a packed column without enzyme and with biocatalysts immobilized on the packaging itself.

In another optional aspect of the invention, an advantage of providing micro-particles is that the quantity and activity of the enzyme may be designed and controlled for a given process, reactor, pumping requirements, or set of conditions.

In another optional aspect of the invention, an advantage is that immobilization of the biocatalysts as part of micro-particles may provide increased stability to the enzyme. More about stability will be described below. The micro-particles with immobilized biocatalysts may have a longer shelf life for storage, shipping, realization, and recycling within the process as the biocataiysts are stabilized on the support material. In some embodiments, the immobilized biocatalysts may become stable to operating conditions in process units other than the absorption unit, such as the desorption unit, and consequently mscro-particles could be used in the absorption and desorption units without the need to remove the micro -particles prior to the desorption unit. In such a process configuration the enzymatic micro-particles may have an Impact in the absorption unit by Increasing the C02 absorption rate but also in the desorption unit since carbonic anhydrase is also known to increase rate of bicarbonate ion transformation into CO; is one of the reactions that would take place in the desorption unit). In this configuration, the removal unit (E-3) would be required to remove deactivated micro-particles and unit (f ~ 4) to add fresh enzymatic micro-particles, However, it may be advantageous to have a separation unit such as a filter between (E-11) and (E-12) to avoid flow of the enzymatic micro-particles through the reboiler and their contact with very high temperatures (depending on the thermoresistance of the biocatalysts of the micro-particles).

In another optional aspect of the invention, an advantage is that the micro-particles can be easily replaced or refurbished. The mixing chamber (E-4) preferably comprises an inlet for receiving recycled micro-particles from the separation unit (E-3) and also an inlet feed for both removing a fraction of used micro-particles and replacing them with new micro-particles, thereby refurbishing the overall batch of micro-particles in the system.

In another optional aspect of the invention, an advantage of the process and system is that the micrc particles can be removed from the ion-rich mixture far easier than conventional free enzymes. By way of example, human carbonic anhydrase type li is an ellipsoid with dimensions of 39 Λ x 42 Λ x 55 Å and is difficult to separate from solution. Thus, the micro-particles can be sized to enable both high absorption rate and easy removal for recycling, in this way, the enzymes can avoid being present in the desorption unit which can involve high temperatures and other conditions that can denature some types of enzymes and enzyme variants. In some embodiments, the block catalytic microparticles are filtered, centrifuged, cyoloned, sedimented or magnetically separated into safirs! separation un-t and other small particles such as precipitates can be separated into a preceding or subsequent separation unit.

The process / system may comprise a separation unit for removal of the miera paritdes. These micro-particles are then preferably pumped back to the inlet of the absorption liquid in the packed column. The selection of the separation unit depends on the size of micro-particles, density, cost and their nature (e.g. magnetic or non magnetic parttete $) TNi process may also comprise a desorption unit In order to regenerate the. bn-rlch solution. In one embodiment, the million psrticles are used in conjunction with an absorption compound in the solution: The absorption compound may be primary, secondary and / or tertiary amines (including alkanolamines); primary * secondary and / or tertiary amino acids; and / or carbonates The absorption compound may more particularly include amines (e.g., piperidine * piperazine and derivatives thereof substituted by at least one alkanol group}, alkanolamines (e.g., monoethanolamine (MEA), 2-amino-2-methyl-propanol) AfrlP), 2- (2-amylthioamino} ethanoi (AEE), 2saminO "2" hydroxymethylM, 3-pfOpanedrull {Tris}, N TIFA) and triethanolamine), dialkytether or polyalkytene glycols (& gt. Dialkytether or dimefhytether or polyethylene glycol); amino acids which may include potassium or sodium salts of amino acids, glycine, proline, arginine, histidine, lysine, aspartic acid, glutamic acid, methionine, serine, threonine, glutamine, cysteine, asparagine, valine, leucine, isoleudne, alanine, valine, tyrosine, tryptophan, phenylalanine, and derivatives such as taurine, hlcyclohexyl l.ri-propane diamine, N-secondary butyl glycine hfrmeihyl M-secondary butyl glycine; and which may include potassium carbonate, sodium carbonate, ammonium carbonate, promoted potassium carbonate solutions and promoted sodium carbonate solutions or promoted ammonium carbonates; or mixtures thereof, Absorption compounds are added to the solution to aid in the GO «absorption and to combine with the catalytic effects of the carbonic anhydrase, ie to the structure or high concentration of sortie absorption compounds, the activity or longevity of the carbonic anhydrase can be threatened. For Instance, free enzymes may be more vulnerable Is denaturing caused by an absorption compound with high ionic strength such as carbonates. Immobilizing the carbonic anhydrase can mitigate the negative effects of such absorption compounds. By providing the carbonic anhydrase immobilized or otherwise supported by micro-particles, the process can yield high C02 transfer rates in the presence of absorption compounds while mitigating the negative effects sueh compounds could otherwise have on free enzymes.

EXAMPLES

Example 1

The micro-p rticie support material may be made of nylon, silica, silica gel, chlcasan, polystyrene, pylymethyl methacrylate, cellulose, magnetic particles, and other materials known to be used for bioeatai immobilization. The micropaids may also be composed of a combination of different materials, for instance, the support may have a core composed of a material having different density or other properties compared to a different surface material which is provided for immobilization or entrapment of the enzymes . For example, the core of the support may be composed of a magnetic material to enable magnetic separation and the surface material may be polymeric such as nylon to support the enzyme. As noted above, in one embodiment the support material may be an aggregate of enzymes to form ClEA or Cl EC. The micro-particles may each define an integral solid volume (e.g., a bead-like shape) or may comprise one or more apertures traversing the main volume of the particle fe.g, a pipe or donut shape). By way of example, the micro-partides may be ovoid, spherical, cylindrical etc.

The micro-particles may be sized in accordance with the requirements of given process conditions. For higher sizes, the compounds, materials and process equipment should be chosen to allow sufficient flow and pumpabillty of the absorption mixture. More about sizing will be discussed hareinhalow.

Example 2

An experiment was conducted in an absorption packed column. The absorption solution is an aqueous solution of methyldletbanolamine (MDEA) 4M- This absorption solution is contacted by a gas phase with a gas phase with a CO CO concentration of 130,000 ppm. Liquid flow rate was 0.65 g / min and gas flow rate was 65 g / ml corresponding to UG or ID (g / g). Gas and absorption solution were at room temperature. Operating pressure of the absorber was set at 1.4 psig, The column has a 7 (S em diameter and a SO cm height Packing material Is polymeric Raschig rings 0.25 inch. Throe tests were performed; the -first with no activator , the second with carbonic anhydrase immobilized to packing support and the third using carbonic anhydrase free in solution at a concentration of 0.5 g per liter of solution.

The results obtained showed that COa transfer rate or CO * removal rate -increased from 6 to 14 mmol. CO2 / min with carbonic anhydrase immobilized onto the surface of Raschig rings. In the presence of free enzymes i.e. carbonic anhyd race free flowing In the solution. the transfer rate increased to 29 mmol / mln. These results demonstrate the positive impact of adding the enzyme in a packed column and that microparticles comprising enzymes can enable improvements.

Similar tests were also performed with solutions of potassium carbonate (20% wfw -1.45 U) and sodium carbonate 0, § M> The impact of free and immobilized enzymes follows the same trend as far ΜΏΕΑ 4 hi

Example 3

To further determine the impact of enzymatic micro-particles on C02 absorption rate, tests were conducted in a hydration cell. This hydration cell reactor was designed and operated under set conditions to control the area of the interface between a gas phase, CO 2, and a liquid phase in the gn absorption process. This device was used to evaluate the impact of enzymatic micro-particles on the C02 absorption rate in a given absorption solution. Tests were conducted as follows: a known volume of the unloaded absorption solution is introduced In the readier; then a known mass of micro-particles is added to the absorption solution (micro-particles may or may not contain enzymes); a CDs stream is flowed through the head spage of the reactor and agitation ss started; The pH of the solution is measured as a function of time; then pH values are converted Into carbon concentration in g C / L using a carbon co-concentration-pH correlation previously determined for the absorption solution; Absorption rates are determined from a plot of C concentration as a function of lime. The impact of the enzyme as a relative absorption rate is reported; ratio of absorption rate in the presence of the enzyme micro-particles to absorption rate in the presence of micro-particles without enzyme, it should be noted that results obtained in hydration ceil reactor cannot be directly compared to those obtained in a packed column because hydrodynamic conditions and mass transfer coefficients are different.

Tests were conducted with the enzyme human carbonic anhydrase type II (HCÅII) immobilized on the surface of nylon micro-particles, if it should be noted that these tests used a non-optimized immobilization protocol and thus the activity of the enzymes could be increased by adjusting the immobilization protocol Nyion micro-particles size ranges from 50-180 pm. Absorption solutions tested were 1.4S M K 2 CO% and 0.5 M IMipCous. Testing temperatures were 2CTC. Methodology was as described in Example 3. Results indicate that C02 absorption rate was increased by 20-30% for both solutions as compared to mreropartides with no enzymes.

Example 5

Tests were conducted with HCAII immobilized on the surface of nylon micro-particles, (using & non-optimized immobilization protocol) Nylon micro-particles size ranges from 50 * 1.60 pm. Absorption solution was 2M MDEA. Testing temperature was 20 C. Enzyme concentrations ranged from 0.1 to 0.5 g / L Methodology was as described in Example 3, Results indicate that enzyme on nylon microparticles increases C02 absorption rate for all tested conditions (see Table 1), absorption rate increased between 40 and 120%.

Table 1 ative Relative CO; transfer rates sn presence of enzyme immobilized on nylon micro-particles In 2M IffiEA solution

Tests were conducted with HCAII immobilized on the surface of cellulose micro-parfides (using a non-optimized immobilization protocol), Ceiluiose micro-parhcJe size Is SO pm. Absorption solution was 2M MDEA, Testing temperature was 20 "C Enzyme concentrations in the solution ranged from 0.1 'to 0.5 g / l. Methodology was as described in Example 3, Results indicate that enzyme on cellulose micro-particles increases CO * absorption rate for enzyme concentration higher than 0.1 g / L (see Table .2) under tested conditions.

Table 2; Relative Co * transfer rates in the presence of enzyme immobilized · »« cellulose micro-particles in a 2M seed solution

Tests were conducted with HCAII immobilized at the surface of nylon micro-particles {using a non-optimized Immobilization protocol). Nylon particle size ranges between 50 and 160 pm. Absorption solutions were 0.6 M of the potassium salt of the following amino acids; glycine, methionine, .taurine and Ν, Ν-dimethyiglycine. Testing temperature was 20 ° C, Enzyme concentration is 0.5 g / L Methodology is as described in Example 3. Results Indicate that enzyme on nylon micro-particles increases C02 absorption rate for all tested amino acid sails (see Table 3). impact of the enzyme was important for Ν, Ν-dimethylglycine, a tertiary amino acid.

Table 3 "Relative COs transfer rates in presence of enzyme Immobilized on nylon micro-particles in Chi M potassium salt of amino acids at an enzyme concentration

if 0.5 g / L

Tests were conducted with cross-linked enzyme aggregates (CLEA) or carbonic anhydrase (using a non-optimized protocol). The enzyme used is a thermophysical variant of enzyme HCAII, designated as 5X. CLEA contains 26% (w / w) of the 5X enzyme. Particle size ranges between 4-9 pm, Absorption solution was 1.45 UK * QOs, Tasting temperature was 20 ° C, Enzyme GonGentratlon was 0.5 g / L, Methodology is as described in Example 3, Tests were conducted with CLEAs and then with deactivated CLEAs as a reference to enable determination of the enzyme impact. Results indicate that CLEAs increase C02 absorption rate by a factor of 3.2,

Tests were conducted with cross-linked enzyme aggregates (CLEA) or carbonic anhydrase (using a non-optimized protocol). The enzyme used is a thermoresistant variant of enzyme HCAII, designated as SX, CLEA contains 26% (w / w) of the SX enzyme. Particle size ranges between 4 »9 pm. Absorption solution was 1M MDEA Testing temperature was 25 ° C, Enzyme concentration was 0.5 g / L, 0¾ absorption tests were performed in a stirred cell, a simple device that can be used to evaluate CO * absorption rates under different conditions. The stirred cell contains the absorption solution (and the enzyme when required). A known pressure of pure OQg is applied to the solution. In these tests, initial CQz pressure is T 000 mbar. Then the pressure decrease is monitored and used to calculate C02 transfer rate in the absorption, Tests were conducted with particles with CLEAs and. without CLEAs to enable determination of the enzyme impact. Results are expressed as a ratio of the C02 transfer rate with CLEAs to the COs transfer rate in the absence of CLEAs. Results indicate that CLEAs increase 00¾ absorption rate by a factor of! .3 to1.7 in the MDEA.

Tests were conducted with HCAil immobilized on the surface of magnetic silica coated Iron oxide micro-particles (using a non optimized immobilization protocol). Particle say © Is 5 pm. Absorption solution was 1.4§ M K 2 CO *. Testing temperature was 20 ° C, Enzyme concentration is 0.2 g / L. Methodology is as described in Example 3, Results indicate that enzyme on magnetic micro-pariids increases CQ $ absorption rate by a factor of 16.

This example provides calculations for the minimum activity density for a given micro-particle size, for an embodiment of the process.

data:

Activity level to fee reached in the absorption solution: 5 x 10s units / L (corresponding to 1 g / L. Soluble carbonic anhydrase),

Materia! density: 1.1 g / mL for nylon particles (~ 1 100 g / L).

Maximum allowable particle concentration :: 300 g / L

Particle diameter:, 10 pm.

Calculations: 1. Surface of a 10 pm particle

2. Volume of a 10 µm particle

3. Total volume of particles per liter to reach the maximum allowable particle concentration:

νγ «300 g / (1,100 g / L) * 0.272 L (corresponding to 2.72 x 1pm3) 4, Number of particles (rp) in 1 L of solution;

6, Total micro-part »cles surface area (A <)

6. Minimum activity density

Adivity density ~ Activity ievel / Ατ * 5x106 / 1.04 x 103 = 0: 03.Un | t WAfmm *

Thus, for 10 pm micro-particles, the minimum activity density to reach an activity level of 5 X 10δ units. WML · is 0:, 03 unit WA / mmY

Thus, if the activity is density. higher than 0.03 unit WA / rnm2, a particle concentration lower than 300 g / L would be needed. Additional examples are shown in Table 4 below.

Example 11

This example provides calculations for the maximum particle size for a given particle concentration, for an embodiment of the process.

data:

Activity level to be read in the absorption solution: 5 x 10 * units / (corresponding to 1 g / L soluble carbonic anhydrase).

Activity density on particles: 0.51 uni / mnfL

Material density: 1.1 g / mt for nylon particles {- 1 100 g / L). Maximum allowable particle concentration: 300 g / L,

Calculations, 1. Total surface area required to reach the activity level:

AT -5 X 10s units / L / (0.51 ur5) «9 S03 922 mm1

Total volume of particles per liter to reach the maximum allowable particle concentration:

Vt - = 300 g / (1 100 g / L) ~ 0.272 L (corresponding to 272 727 mms)

Thus, a volume of 272 727 mm2 of particles .would be present per liter of mixture. 2

Maximum radius of a particle:

For spherical particles: * Ap ~ · 4tt (radius) 1 * Vp - 4/3 π (radius) ®

Thus, the maximum size of a partida would raise a diameter of shout 166 pm. Thus, If micro-pariidas are of a smaller diameter, the resulting mixture or absorption solution will

This method can be used to evaluate the maximum particle size allowable for many conditions of activity level, activity density, particle density and maximum allowable partide concentration * Table 5 below shows different scenarios and corresponding particle sizes.

While the calculations in the above Examples are for spherical micro-particles, corresponding calculations or estimates may be performed for other micro-particle geometries.

An absorption was conducted in an absorption packed column * The absorption solution is an aqueous solution of potassium carbonate. (K ^ COg) 1.45 M> This absorption solution is contacted counter-ourrerrtly with a gas phase with a C02 concentration of 130,000 ppm. Liquid flow rate was 0.60 g / min and gas flow rate was 60 g / min corresponding to L / G of 10 (g / g). Gas and absorption solution were at room temperature. The operating pressure of the absorber was set at 1.4 psig. The column has a 7.5 cm diameter and a SO cm height. Packing material is polymeric Rasch rings 0.25 inch. Two tests were performed: the first with no activator, the second with CtEAs containing 26% (w / w) of the SX enzyme. Particle size ranged from 4-9 pm. The enzyme concentration suitable for the absorption solution was 0.1 g / L

The results obtained showed that -CO * transfer rate was increased by a factor of 2.7 as the CQ * removal rate increased from 11 to 30 mmol / min with the CtEAs.

Example 13

This example provides data to demonstrate that enzyme immobilization increases enzyme stability. Data are shown for enzymes immobilized on nylon micro-particles. To evaluate the impact of immobilization on enzyme stability, the stability of immobilized enzymes was evaluated and compared to the stability of the same enzyme in a soluble form. The micro-particles were: prepared through the following noo-optsmlzed steps' - Surface treatment of nylon micro-particles · with giutaraldehyde - Addition of poiyethyieneimine - Addition of g! utaraidehyde

Enzyme fixation, (human carbonic anhydrase typo! I} - Aldehyde group blocking with polyethylene imine

Following immobilization, the enzymes mlcro-panides and soluble enzymes were exposed to IVIPEA 2M at 40 C, At specific exposure times, samples were withdrawn and activity was measured. Results are «« pressed as residual activity, which is the ratio of the activity of the enzyme at a given exposure time t to the enzyme activity at time 0. Figure 4 illustrates the results.

Results show that free enzyme loses all activity with 10 days * whereas micro-particles still retain 40% residual activity after 58 days. From this result, It is clear that Immobilization increases enzyme stability under these conditions.

These results show the potential of immobilization to increase the stability of carbonic anhydrase at higher temperature conditions which are found in a C02 capture process, in optional aspects of the present invention, the rnlcro parficles enable increased stability of around or above the stability increase illustrated. in the examples,

It should also be noted that the absorption and desorption units that may be used with embodiments of the present invention may be different types depending on various parameters arid operating conditions. The units may be, for example, in the form of a packed reactor, spray reactor, fluidized bed reactor, etc., may have various configurations such as vertical, horizontal, etc., and the overall system may use multiple units in parallel or In series, as the case may be, it should be understood that the embodiments described and illustrated above do not restrict what has actually been invented.

Claims (18)

1. A system for capturing C02from a C02-containing gas comprising: micro-particles comprising a support material and biocatalysts supported by the support material, the biocatalysts promoting dissolution and transformation of C02 into bicarbonate and hydrogen ions; an absorption unit configured for contacting the C02-containing gas with an absorption mixture comprising a liquid solution and the micro-particles, and producing a C02-depleted gas and an ion-rich mixture comprising the microparticles; a separation unit configured for receiving the ion-rich mixture and removing the micro-particles therefrom to produce an ion-rich solution; a desorption reactor for receiving the ion-rich aqueous mixture to enable transformation of the bicarbonate and hydrogen ions into C02 gas and water, thereby producing a C02 gas stream and an ion-depleted solution; and an addition unit configured to receive micro-particles from the separation unit and adding micro-particles back into the ion-depleted solution for recycling back into the absorption unit.

2. The system of claim 1, wherein the absorption unit comprises a packed reactor.

3. The system of claim 1 or 2, wherein the absorption mixture comprises an absorption compound selected from piperidine, piperazine, derivatives of piperidine or piperazine which are substituted by at least one alkanol group, monoethanolamine (MEA), 2-amino-2-methyl-1 -propanol (AMP), 2-(2-aminoethylamino)ethanol (AEE), 2-amino-2- hydroxymethyl-1,3-propanediol (Tris), N-methyldiethanolamine (MDEA), dimethylmonoethanolamine (DMMEA), diethylmonoethanolamine (DEMEA), triisopropanolamine (TIPA), triethanolamine, dialkylether of polyalkylene glycols, dialkylether or dimethylether of polyethylene glycol, amino acids comprising glycine, proline, arginine, histidine, lysine, aspartic acid, glutamic acid, methionine, serine, threonine, glutamine, cysteine, asparagine, leucine, isoleucine, alanine, valine, tyrosine, tryptophan, phenylalanine, and derivatives such as taurine, N,cyclohexyl 1,3- propanediamine, N-secondary butyl glycine, N-methyl N-secondary butyl glycine, , diethylglycine, dimethylglycine, , sarcosine, , methyl taurine, methyl-a-aminopropionic acid, N-(p-ethoxy)taurine, N-(p-aminoethyl)taurine, N-methyl alanine, 6-aminohexanoic acid and potassium or sodium salts of the amino acids; potassium carbonate, sodium carbonate, ammonium carbonate, promoted potassium carbonate solutions and promoted sodium carbonate solutions or promoted ammonium carbonates; or mixtures thereof.

4. A system for capturing C02from a C02-containing gas comprising: micro-particles comprising a support material and biocatalysts supported by the support material, the biocatalysts promoting dissolution and transformation of C02 into bicarbonate and hydrogen ions; an absorption unit configured for contacting the C02-containing gas with an absorption mixture comprising a liquid solution and the micro-particles, and producing a C02-depleted gas and an ion-rich mixture comprising the microparticles; and a desorption reactor for receiving the ion-rich aqueous mixture comprising the micro-particles to enable transformation of the bicarbonate and hydrogen ions into C02 gas and water, thereby producing a C02 gas stream and an ion-depleted solution.

5. The system of claim 4, wherein the micro-particles are sized so as to be within an order of magnitude or smaller than a thickness of a reactive liquid film formed between the absorption mixture and the C02 in the absorption unit.

6. The system of claim 4 or 5, wherein the micro-particles are sized between about 1 pm and about 100 pm.

7. The system of any one of claims 4 to 6, wherein the micro-particles are provided in the absorption mixture at a maximum particle concentration of about 40% w/w or at a maximum particle concentration of about 30% w/w.

8. The system of any one of claims 4 to 7, wherein the support is at least partially composed of nylon, cellulose, silica, silica gel, chitosan, polystyrene, polymethylmetacrylate, magnetic material, or a combination thereof.

9. The system of any one of claims 4 to 8, wherein the density of the support material is between about 0.6 g/ml and about 3 g/ml.

10. The system of any one of claims 4 to 9, wherein the biocatalysts are carbonic anhydrase.

11. The system of claim 10, wherein the carbonic anhydrase is immobilized on a surface of the support material of the microparticles, entrapped within the support material of the microparticles, or a combination thereof.

12. The system of any one of claims 4 to 11, wherein the biocatalysts are entrapped inside or fixed to a porous coating material that is provided around a support particle.

13. The system of any one of claims 4 to 12, wherein the absorption unit is a packed reactor and the micro-particles are sized and provided in a concentration such that the absorption mixture flows through the packed reactor.

14. The system of any one of claims 4 to 13, further comprising an addition unit for adding an amount of the micro-particles to the ion-depleted solution before recycling the ion-depleted solution for further contacting the C02-containing gas in the absorption unit.

15. The system of any one of claims 4 to 14, wherein the absorption mixture comprises water and an absorption compound.

16. The system of claim 15, wherein the absorption compound comprises piperidine, piperazine, derivatives of piperidine or piperazine which are substituted by at least one alkanol group, monoethanolamine (MEA), 2-amino-2-methyl-1 -propanol (AMP), 2-(2-aminoethylamino)ethanol (AEE), 2-amino-2-hydroxymethyl-1,3-propanediol (Tris), N-methyldiethanolamine (MDEA), dimethylmonoethanolamine (DMMEA), diethylmonoethanolamine (DEMEA), triisopropanolamine (TIPA), triethanolamine, dialkylether of polyalkylene glycols, dialkylether or dimethylether of polyethylene glycol, amino acids comprising glycine, proline, arginine, histidine, lysine, aspartic acid, glutamic acid, methionine, serine, threonine, glutamine, cysteine, asparagine, leucine, isoleucine, alanine, valine, tyrosine, tryptophan, phenylalanine, and derivatives such as taurine, N,cyclohexyl 1,3-propanediamine, N-secondary butyl glycine, N-methyl N-secondary butyl glycine, , diethylglycine, dimethylglycine, , sarcosine, , methyl taurine, methyl-a-aminopropionic acid, N-(3-ethoxy)taurine, N-(3-aminoethyl)taurine, N-methyl alanine, 6-aminohexanoic acid and potassium or sodium salts of the amino acids; potassium carbonate, sodium carbonate, ammonium carbonate, promoted potassium carbonate solutions and promoted sodium carbonate solutions or promoted ammonium carbonates; or mixtures thereof.

17. The system of claim 15, wherein the absorption compound comprises potassium carbonate.

18. The system of any one of claims 4 to 17, further comprising a pump for receiving and pumping the ion-rich mixture to the desorption unit, and wherein the micro-particles are further sized and provided in a concentration such that the ion-rich mixture comprising the micro-particles is pumpable.