CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Patent Application No. 61/781,452, filed March 14, 2013, entitled "Devices And Methods For Co-current Chemical Looping Systems" (Docket OSU 0082 MA), the teachings of which are incorporated by reference herein.

BACKGROUND ART

Field

The present disclosure relates to chemical looping systems for converting fuel, and specifically to devices used in chemical looping systems.

Technical Background

There is a constant need for clean and efficient energy generation systems. Many of the commercial processes that generate energy carriers such as steam, hydrogen, synthesis gas (syngas), liquid fuels, and/or electricity are based on fossil fuels. Furthermore, the dependence on fossil fuels is expected to continue in the foreseeable future due to the lower costs compared to some renewable sources. Currently, the conversion of carbonaceous fuels such as coal, natural gas, and petroleum coke is usually conducted through a combustion or reforming process. However, combustion of carbonaceous fuels is a carbon intensive process that emits large quantities of carbon dioxide to the environment.

As demands increase for cleaner and more efficient systems of converting fuel, the need arises for improved systems and methods, and system components therein, which can convert fuel effectively while reducing pollutants.

SUMMARY OF INVENTION According to one embodiment, a chemical looping system may comprise a first reactor and a second reactor, the second reactor connected to the first reactor by a first connection and a second connection. The first connection may be disposed downstream of the first reactor and upstream of the second reactor and the second connection may be disposed downstream of the second reactor and upstream of the first reactor, thereby defining a loop in which solid particles may circulate. The first reactor may be a co- current moving bed reactor that may comprise a gas inlet, a gas outlet, a solid particles inlet directly coupled to the second connection, and a solid particles outlet directly coupled to the first connection. The second reactor may be a fluidized bed reactor that may comprise a solid particles inlet directly coupled to the first connection, and a solid particles outlet directly coupled to the second connection. The first connection may comprise a non-mechanical zone seal and a solids circulation device. The non- mechanical zone seal may be configured to deliver a stream of sealant gas within the first connection to restrict gas from the first reactor from entering the second reactor. The second connection may comprise a gas-solids separation device, a solids storage vessel, and a non-mechanical zone seal. The non-mechanical zone seal may be configured to deliver a stream of sealant gas within the second connection to restrict gas from the second connection from entering the first reactor.

In another embodiment, a co-current moving bed reactor may comprise a gas inlet, a gas outlet, a solid particles inlet, a solid particles outlet, a reaction chamber, and a gas exit chamber. The co-current moving bed reactor may contain solid particles. The gas exit chamber may be separated from the reaction chamber by a gas-solids partition. The gas outlet may be directly coupled to the gas exit chamber. The solid particles inlet and solids particles outlet may be directly connected to the reaction chamber. The gas- solids partition may be operable to restrict passage of solid particles from entering the gas exit chamber and may be operable to allow for the flow a gas from the reaction chamber to the gas exit chamber.

In yet another embodiment, a co-current moving bed reactor may comprise a gas inlet, a gas outlet, a solid particles inlet, a solid particles outlet, and one or more internal gas disengagement areas. The co-current moving bed reactor may contain solid particles. The internal gas disengagement areas may be defined by internal structural walls and an interface between the solid particles and gases exiting the first reactor. The internal gas disengagement areas connect to the gas outlet. Additional features and advantages of the devices and methods for chemical looping systems and methods and processes for manufacturing the same will be set forth in the detailed description which follows, and in part will be readily apparent to those skilled in the art from that description or recognized by practicing the embodiments described herein, including the detailed description which follows, the claims, as well as the appended drawings.

It is to be understood that both the foregoing general description and the following detailed description describe various embodiments and are intended to provide an overview or framework for understanding the nature and character of the claimed subject matter. The accompanying drawings are included to provide a further understanding of the various embodiments, and are incorporated into and constitute a part of this specification. The drawings illustrate the various embodiments described herein, and together with the description serve to explain the principles and operations of the claimed subject matter.

BRIEF DESCRIPTION OF DRAWINGS The following detailed description of specific embodiments of the present disclosure can be best understood when read in conjunction with the following drawings, where like structure is indicated with like reference numerals and in which:

FIG. 1 schematically depicts a reactor system, according to one or more embodiments described herein; FIG. 2 schematically depicts a multi-stage reactor, according to one or more embodiments described herein; FIG. 3 schematically depicts a non-mechanical zone seal, according to one or more embodiments described herein;

FIG. 4 graphically depicts a reactor system pressure profile, according to one or more embodiments described herein;

FIG. 5 schematically depicts a side view of a reactor, according to one or more embodiments described herein;

FIG. 6 schematically depicts a side view of a reactor, according to one or more embodiments described herein;

FIG. 7 schematically depicts a side view of a reactor, according to one or more embodiments described herein;

FIG. 8 schematically depicts a gas-solids partition, according to one or more embodiments described herein;

FIG. 9 schematically depicts a side view of a reactor, according to one or more embodiments described herein;

FIG. 10 schematically depicts a side view of a reactor, according to one or more embodiments described herein;

FIGS. 11A and 11B schematically depict top views of reactors, according to one or more embodiments described herein;

FIGS. 12A, 12B, and 12C schematically depict internal structures of reactors, according to one or more embodiments described herein;

FIG. 13 schematically depicts a side view of a reactor, according to one or more embodiments described herein;

FIG. 14 schematically depicts a side view of a reactor, according to one or more embodiments described herein; FIGS. 15A, 15B, and 15C schematically depict solids delivery devices, according to one or more embodiments described herein;

FIG. 16 schematically depicts a side view of a particle makeup device, according to one or more embodiments described herein; and FIG. 17 schematically depicts a side view of a particle makeup device, according to one or more embodiments described herein.

DESCRIPTION OF EMBODIMENTS

Disclosed herein are chemical reactor systems and devices for such systems that may be utilized for chemical production methods. The devices and systems described herein may be utilized for a wide variety of other purposes in chemical reactor systems which may convert any number of chemical feedstocks into product compositions. In one embodiment, the systems and devices may be utilized for converting gaseous feedstock fuels, such as, for example, natural gas, into gaseous chemical products, such as, for example, syngas. In another embodiment, the systems and devices described herein may be operable to convert feedstock fuel sources into other product fuel sources. In some embodiments described herein, the feedstock chemical and the product chemical may be gaseous.

In one embodiment, the devices and systems described herein may be operable to produce syngas, or another gaseous product, from natural gas, or another gaseous feedstock, by utilizing a chemical looping reaction scheme where oxygen carrying materials, such as materials containing metal oxides, are reversibly reduced and oxidized. The oxygen carrying materials, which may be in the form of particles, such as particles having a diameter of between about 0.5 mm and about 10 mm, may cycle between a reduction reactor and an oxidation reactor. While the devices and systems described herein may be described in the context of a chemical looping system that produces syngas from natural gas, the systems and devices disclosed herein are not limited in any way to such a chemical reaction process, and may be utilized in other industrial chemical processes. Additionally, while some the systems and methods described herein may utilize composite metal oxides as oxygen carrying materials, such oxygen carrying materials are not limited to composite metal oxides. In other embodiments, the disclosed systems and devices may be used to process solid and liquid feedstock fuels including coal, biomass, char, solid wastes, and liquid hydrocarbons. Examples of chemical looping reaction systems may be found in

PCT/US2014/014877 (attorney docket OSU 0080 WO), which is incorporated herein it is entirety. In one embodiment, a reduction reaction of a solid oxygen carrying material with natural gas may produce syngas, and an oxidation reaction of the reduced oxygen carrying material may regenerate the reduced oxygen carrying material. Generally, syngas comprises carbon monoxide and hydrogen, and may comprise some other chemicals, such as, but not limited to, carbon dioxide and steam (H ₂ 0). The syngas may be ready for use in downstream synthesis reactions to produce various hydrocarbons (>C such as, but not limited to, methanol, dimethyl ether, gasoline, and diesel. The reduced composite metal oxide from the reduction reaction (after the syngas production) may be regenerated by oxidation with air, or another oxidant such as oxygen, steam, carbon dioxide, or combinations thereof, in an oxidation reactor, and then may be recycled back to the initial reduction reactor, such that the composite metal oxides may be recycled and may be continually used in the oxidation and reduction reactions. The cyclic reduction (endothermic) and oxidation (exothermic) reactions of oxygen carrying materials may form a reaction and heat integrated process loop that may perpetuate.

FIG. 1 shows one embodiment of a chemical reaction system 150 comprising a plurality of devices disposed within the system and in direct communication, such as coupled directly with no intervening components there between, or indirect communication, such as coupled with one or more intervening components there between, with one another. The devices may include a first reactor 100 and a second reactor 200. The first reactor 100 and second reactor 200 may be connected by a first connection 600 and a second connection 700. The system may further comprise solid particles, such as solid oxygen carrying particles, which may be disposed within the system and circulate between the first reactor 100 and second reactor 200. In one embodiment, the first reactor 100 may be a reduction reactor where oxygen carrying particles are reduced and the second reactor 200 may be an oxidation reactor where oxygen carrying particles are oxidized. The first connection 600, the second connection 700, the first reactor 100, and the second reactor 200 may define a loop, the solid particles being operable to circulate through the loop. The first connection 600 may be the section of the reactor system 150 positioned downstream of the first reactor 100 and between the first reactor 100 and the second reactor 200. The second connection 700 may be the section of the reactor system 150 positioned downstream of the second reactor 200 and between the second reactor 200 and the first reactor 100. The solid particles may circulate in a single direction through the looping system between the first reactor 100 and the second reactor 200. For example, in the embodiment of FIG. 1, the solid particles may be operable to circulate in a counter-clockwise direction through the loop, relative to the schematic drawing of FIG. 1. In such an embodiment, the solid particles may be movable from the first reactor 100 to the second reactor 200 via the first connection 600 and movable from the second reactor 200 to the first connection 600 via the second connection 700.

In one embodiment, the first reactor may comprise a gas inlet 110, a gas outlet 120, a solid particles inlet 741 directly coupled to the second connection 700 at a connection segment 740, and a solid particles outlet 611 directly coupled to the first connection. 600 and a connection segment 610. The first reactor 100 may be a co-current moving bed reactor where inlet gas and solid particles move downward.

In one embodiment, the solid particles may be reduced by the inlet gas in the first reactor 100. For example, composite metal oxide particles may be introduced as MeO _x , such as FeO _x Ti0 ₂ , at the top, and may be converted to MeO _y , such as FeO _y Ti0 ₂ , at the bottom of the reactor. In one embodiment, the operation range of composite metal oxide may be controlled in the range of 1.5>x>l>y>0.3 to ensure a high particle oxygen carrying capacity as well as maintaining the quality of syngas product, i.e. mainly CO and H ₂ with minimal C0 ₂ and H ₂ 0. In this example, the oxygen carrier particles, MeO _x may be reduced by the inlet fuel gas to a lower oxidation state MeO _y at the reduction reactor outlet. In a co-current downward moving-bed reactor, the diameter and height of the reactor may be configured to satisfy the short residence time required for gaseous reactants, which may be normally in the range of seconds, and longer residence time generally required for composite oxygen carrier particles, which may be in the range of tens of minutes, simultaneously. The reactor design should be determined by the reaction rate of the oxygen carrying particles with the feedstock and operating conditions of the reactor. In one embodiment, the operational temperature of the reduction reactor may be in the range from about 500°C to about 1250°C and the operational pressure may range from about 1 bar to about 50 bars, depending on the inlet pressure of feedstocks as well as the desired syngas composition for downstream syngas conversion.

Referring now to FIG. 2, in another embodiment, the first reactor 100 may comprise a series of interconnected reactors 152, 154, 156 such as, but not limited to, fluidized bed reactors, moving bed reactors, or combinations thereof. Each reactor in this series may have gas-solids counter-current flow, as shown in FIG. 2, or alternatively, a co-current flow. However, the overall direction of the gas and solids flow in the series of reactors may be co-current, such as downward as shown in FIG. 2, such that each reactor stage is countercurrent but the overall reactors apparatus is co-current. Solid particles may be transferred between the interconnected reactors 152, 154, 156 through solid particle transports 157, 159 in a downward path. Product gas, gas produced in the first reactor 100, such as syngas, can exit the system though gas outlet 120 from the top of the bottom reactor 154, and product gas from the top of the top reactor 156 and top of the middle reactor 152 can be transported to the bottom of the middle reactor 152 and bottom of the bottom reactor 154 through gas transports 153 and gas transport 155, respectively. Outlet gas product may be separated from solids in the bottom reactor 154 of this reactor assembly such that the solids from the bottom reactor 154 are transported to the second reactor 200 via the first connection 600. Multiple reactors in series may also promote short residence time of gas reactant and long residence time of solid particles. In one embodiment, the second reactor 200 may comprise a solid particles inlet 631 directly coupled to the first connection 600, shown at the joining of the connection segment 630 and the second reactor 200, and a solid particles outlet 711 directly coupled to the second connection 700 shown at the joining of a connection segment 710 and the second reactor 200. The second reactor may be a fluidized bed reactor. The second reactor 200 may have a gas inlet 210 that may, in one embodiment, receive oxidizing gas for an oxidation reaction. Oxidized gas may travel through the second connection 700 and be released at the gas-solids separation unit 300.

In one embodiment, the solid particles may be oxidized in the second reactor 200. The first reactor 100 may be configured to oxidize reduced composite oxygen carrier particles in a fluidized bed arrangement with air or other oxygen-containing gas entering from a gas inlet 210. For example, composite oxygen carrier particles with relatively low oxidation state may be re-oxidized in the first reactor 100 to a higher valence state, such as, in some embodiments, about 3+. The second reactor 200 may release heat during an oxidation reaction of oxygen carrier particles. In some embodiments, the gas inlet 210 of the second reactor 200 may comprise an air filled line or tube, which may be utilized to provide oxidizing gases to oxidize the oxygen carrier particles. In another embodiment, the second reactor 200 may be a series of reactors in combination, so as to provide a desired oxidation reaction for oxygen carrier particles. In one embodiment, reduced oxygen carrier particles, MeO _y may be oxidized by the oxygen-containing gas, such as air, to its higher oxidation state MeO _x . In one embodiment, the second reactor 200 is a turbulent fluidized bed reactor wherein enhanced contact between solid particles and oxygen-containing gas may be achieved, as well as good thermal transport. The diameter and height of the second reactor 200 may be properly designed to ensure full and uniform reaction, such as oxidation, of oxygen carrier particles. Some features of the second reactor 200 may be determined by the kinetics and hydrodynamics of the selected oxygen carrier particles, stoichiometric ratio between oxygen carrier particles and oxygen-containing gas, as well as the operational conditions of the reactors. In one embodiment, the operational temperature of an oxidation reaction in the second reactor 200 may be in the range of from about 500°C to about 1250°C and the operational pressure may range from about 1 bar to about 50 bars, depending on the pressure of feedstocks as well as the requirement of the downstream syngas conversion process.

The first connection 600 may generally comprise one or more system devices, such as, but not limited to, a non-mechanical zone seal 500 and/or a solids circulation device 400. The first connection 600 may further comprise one or more connection segments 610, 620, 630 for transporting the solid particles from the first reactor 100 to the second reactor 200 and through the devices of the first connection 600. The connection segments 610, 620, 630 may be, for example, pipes, hoses, lines, canals, channels, conduits, or any other suitable mechanism for transporting solid particles. The number and location of the connection segments 610, 620, 630 may depend on the number of system devices of the first connection 600. In some embodiments, the devices may be directly connected to one another or to the first reactor 100 or second reactor 200.

The second connection 700 may generally comprise one or more system devices, such as, but not limited to, a gas-solids separation device 300, a non-mechanical zone seal 500, and/or a solids storage vessel 800. The second connection 700 may further comprise one or more connection segments 710, 720, 730, 740 for transporting the solid particles from the second reactor 200 to the first reactor 100 and through the devices of the second connection 700. The connection segments 710, 720, 730, 740 may be, for example, pipes, hoses, lines, canals, channels, conduits, or any other suitable mechanism for transporting solid particles. The number and location of the connection segments 710, 720, 730, 740 may depend on the number of system devices of the second connection 700. In some embodiments, the devices may be directly connected to one another or to the first reactor 100 or second reactor 200.

Generally, the non-mechanical zone seal 500 of the first connection 600 may comprise a stream of sealant gas 512 within the first connection 600 operable to restrict gas from the first reactor 100 from entering the second reactor 200. The non-mechanical zone seal of the second connection 700 may comprise a stream of sealant gas 512 within the second connection 700 operable to restrict gas from the second connection 700 from entering the first reactor 100. The solids storage vessel 800 may be any container which can contain the solid particles prior to their entrance to the first reactor 100. For example, the solid storage vessel 800 may be a drum or tank. The solids storage vessel 800 may comprise a solid particles inlet directly coupled to a connection segment 720 of the second connection 700 and may comprise a solid particles outlet directly coupled to a connection segment 730 of the second connection 700. The solid storage vessel 800 may further comprise a suitable solids delivery device or mechanism. Solids delivery devices may include, but are not limited to, pneumatic devices, conveyors, lock hoppers, or the like. The solid particles discharged from the gas-solids separation device 300 may be stored in the solid storage vessel 800, which may be sealed by gas from the first reactor 100 using a non- mechanical zone seal 500.

In one embodiment, as shown in FIG. 1, the chemical reactor system comprises system components in a specified order relative to one another. For example, relative to the motion of the solid particles (counter clockwise in FIG. 1) and starting from the first reactor, the non-mechanical zone seal 500 of the first connection 600 may be downstream relative to the first reactor 100, the solids circulation device 400 may be downstream relative to the non-mechanical zone seal 500 of the first connection 600, the second reactor 200 may be downstream relative to the solids circulation device 400, the gas-solids separation device 300 may be downstream relative to the second reactor 200, and the solids storage vessel 800 may be downstream relative to the gas-solids separation device 300. However, in other embodiments, the devices may be in other arrangements.

In one embodiment, a gas-solids separation device 300 may be installed wherein oxygen-depleted gas and/or attrited solid particles, such as fractured or ground down particles, may be separated from larger, non-attrited solid particles. Solid particles may attrite or break over successive reduction and oxidation cycles. The fine particles from the attrition and breakage may need to be removed from the system to avoid possible failure of the system. In one embodiment, the gas-solids separation device 300 may be a cyclone with a designed cut-off particle size and efficiency. In another embodiment, the gas- solids separation device 300 may be a disengagement chamber operable such that solids particles with a diameter less than a designed value may be entrained and carried by the gas flow while larger particles will flow downwards driven by the gravity. In yet another embodiment, a cyclone and a disengagement device may be used in series. Other separating devices and methods to fine particles from bulk solids, through either non-mechanical or mechanical means, such as sieving with a sieve device, may be used.

In some embodiments, the chemical reaction system 150 may comprise one or more non-mechanical zone seals 500. Non mechanical zone seals 500, as used herein, may be any seal that does not require regular mechanical movement by its parts. For example, a conventional valve may be a mechanical seal because it requires mechanical movement of its parts to restrict flow or seal a connector. In one embodiment, a non- mechanical zone seal 500 may comprise a stream of sealant gas 512 that is injected into the first connection 600 or second connection 700 that may be operable to restrict gas from the first reactor 100 or second reactor 200 from moving into other sections of the reactor system 150, such as flowing freely between the first reactor 100 and second reactor 200. FIG. 3 shows an example of a non-mechanical zone seal 500 on the first connection 600. However, the same designs and principles of the non-mechanical zone seal 500 on the first connection 600 apply to a non-mechanical zone seal 500 that may be on the second connection 700. Referring to the embodiment of FIG. 3, a gaseous stream 510 comprising sealant gas 512 may be injected into or between connection segments 610, 620 of the first connection 600. For example, the connection segments 610, 620 may be standpipes. The non-mechanical zone seal 500 may prevent the processing gas from each reactor section from entering the other while allowing the solids to pass through. Solid particles may move downward from the bottom of the first reactor 100 and through the first connection 600. The gaseous stream 510 of sealant gas 512 may be an inert gas, such as, but not limited to, H ₂ 0, N ₂ , He, Ne, Ar, Kr, Xe, Rn, or combinations thereof.

The gaseous stream 510 may be injected into the first connection 600 where the gas may split into two streams: one flowing upwards against solids movement, and one flowing downwards co-current with solids movement, so that both the first reactor 100 and the second reactor 200 only receive zone seal gas from the gaseous stream 510, not gas from the other reactor. Referring again to FIG. 3, to ensure the zone seal gas flow splits, so as to prevent the reactant gas of the first reactor 100 or second reactor 200 from entering of opposite reactor, a locally highest pressure point P3, which may be located at the entrance point of the gaseous stream 510, may be greater than the pressure PI at the solids outlet of the first reactor 100 and the pressure P2 at the solids inlet 631 of the second reactor 200.

The injection point of the gaseous stream 510 may be anywhere along the first connection 600, such as a standpipe, and may have either single or multiple injection points. In some embodiments, the pressures PI and P2 are substantially equal, wherein the zone seal gas injection point may be located at or near the middle of the first connection 600 so the gas may be evenly split to provide the same tolerance pressure fluctuations at PI and P2. In some embodiments, PI and P2 are not substantially equal, and as such, the injection point of the gaseous stream 510 may be located closer to the first reactor 100 or second reactor 200. For example, if P2 is greater than PI, the injection point of the gaseous stream 510 may be placed closer to the second reactor, and vice versa. In the embodiment of FIG. 3, higher pressure at PI than P2 may make it desirable to locate the injection point of the gaseous stream 510 closer to the first reactor 100. In one embodiment, the flow of the gaseous stream 510 may be minimized to reduce the operating cost and decrease the inert gas content in the product gas stream. The inner diameter (ID) of the connection segment 610 in FIG. 3 may be significantly smaller than the first reactor 100 with which it directly connects.

Referring now to FIGS. 1 and 4, in some embodiments, one or more non- mechanical zone seals 500 may be used to promote the balance of pressure differences between the first reactor 100 and second reactor 200. For example, the one or more non- mechanical zone seals 500 may be positioned at a point operable to balance the pressure difference between the first reactor 100 and second reactor 200. FIG. 1 shows pressure reference locations A, B, C, D, E, F, G, and H, which correspond to the pressure at those locations versus the relative height of the pressure reference locations of one embodiment of a chemical reaction system 150.

In one embodiment, shown in FIGS. 1 and 4, a co-current moving bed chemical looping system for syngas production from natural gas may comprise a standpipe as connection segments 720, 730, 740, a standpipe as connection segments 610, 620, a riser as connection segment 710, and a solids circulation device 400. As shown in FIG. 4, the system pressure balance may be obtained and controlled by the placement and operation of the non-mechanical zone seals 500. For example, the pressure differences between points C and D and point G and H of FIG. 4 represent the pressure drops across the first reactor 100 and second reactor 200, respectively. The pressure differences between points A and C and points D and F may be very high due to the pressure distribution of the system. In one embodiment, the zone seal gas injection points B and E may have pressures higher than the two ends of the standpipes, i.e. points A and C and points D and F, to prevent gas mixing from each reactor section. By locating the zone seal gas injection point B near the bottom section of the first connection 600, a larger pressure drop may be generated from point B to point A than from point B to point C. Thus, the pressure difference between points A and C are offset. By locating the zone seal gas injection point E near the bottom section of the first connection 600, a larger pressure drop may be generated from point E to point D than from point E to point F. Thus, the pressure difference between points E and F may be offset.

For example, in one embodiment, when the first reactor 100 is a co-current moving bed reactor, a large pressure difference between the top and bottom of the first reactor, points C and D, may exist due to the drag force generated by the velocity difference between gas and solids. The difference in pressure between points C and D may be related to the operational condition and configuration of the first reactor 100 such as the bed height, gas velocity and composition, particle properties, operating pressure and temperature, and outlet pressures of gas-solids separation device 300.

Now referring to FIGS. 5 and 6, in one embodiment, the first reactor 100 may comprise a reaction chamber 112 and a gas exit chamber 114, wherein the reaction chamber 112 and the gas exit chamber 114 may be separated by a gas-solids partition 116. The gas exit chamber 114 may be formed by the gas-solids partition 116 and an outer wall 118. The gas outlet 120 of the first reactor 100 may be directly coupled to the outer wall 118 of the gas exit chamber 114. The gas outlet 120 may allow for reaction product gases 122, as well as sealant gas 512 from connection segment 610 to pass out of the reactor system 150. The first reactor 100 may comprise a solids particles outlet 611 at the meeting of the first reactor 100 and the connection segment 610 of the first connection 600. The gas-solids partition 116 may be operable to restrict passage of solid particles in the reaction chamber 112 from entering the gas exit chamber 114 while allowing for sealant gas 512 from the first connection 600 and reaction product gases 122 from the reaction chamber 112 to flow from the reaction chamber 112 to the gas exit chamber 114.

Still referring to FIGS. 5 and 6, in some embodiments, the gas-solids partition 116 defines a tapered transition section 147 that may be disposed proximate a bottom portion of the first reactor 100. In some embodiments, the tapered transition section may be inside of the reactor, such as comprising a gas-solids partition, and in other embodiments, the tapered transitions section may be portion of the outer wall of the reactor. The tapered gas-solids partition 116 may be directly coupled to the first connection 600, wherein the tapered gas-solids partition 116 is configured to deliver the solid particles to the first connection. For example, the gas-solids partition 116 may be in a funnel shape, or any other shape defining a tapered shape that narrows the reaction chamber 112 until it matches the width of the connection segment 610. The width of the gas-solids partition 116 may reduce towards the bottom of the first reactor. The gas velocity in the reaction chamber 112 near the tapered transition section 147 may gradually increase from the top of the tapered transition section 147 to the top tip of the first connection 600 if the gas is not discharged gradually. The increased gas velocity may cause local fluidization of solids. Without being bound by theory, local fluidization in the reactor may cause operational problems in the system such as arching, bridging, local non-uniformity of temperature and/or gas, all of which may cause solids circulation to cease and lead to a pressure imbalance of the system. The tapered gas- solids partition 116 may not increase the flow rate requirement for sealant gas 512 and thus may keep the minimal sealant gas 512 content in the product stream of the gas outlet 120. The tapered gas-solids partition 116 may have an angle sufficient to maintain smooth movement of the solid particles near the bottom of the first reactor 100. The angle of the taper may be dependent on the solids media shape and material properties as well as the material properties of the tapered transition section 147. Generally, the angle may be greater than the repose angle of the solid particles used in the reactor system to avoid possible channeling flow of solids particle or a rat hole effect, wherein particles adjacent the wall are stagnant while particles near the center of the flow channel flow freely resulting in particles adjacent the wall becoming immobile. In some embodiments, the flow rate of sealant gas 512 into the first reactor may be less than about 5%, or even about 2%, of the flow rate of the reaction product gases 122.

Referring now to FIG. 5, in one embodiment, the tapered gas-solids partition 116 comprises one or more porous filters, such as for example, a plurality of porous muffler filters 124 that may be distributed along the gas-solids partition 116. The filter size, pore size, number, and distribution of the muffler filters 124 may be determined by the size of the first reactor 100, flow rate of the first reactor 100, solid particle properties, cost, and other properties of the like in the system. In another embodiment, the gas-solids partition 116 may be made of a screen, as shown in FIG. 6. The screen 116 may retain the solid particle inside of the reaction chamber 112 while allowing gases, including reaction product gases 122 and sealant gas 512 from the connection segment 610 to flow through to the gas exit chamber 114. In another embodiment, openings are made through the wall of the gas-solids partition 116. The openings, such as holes, may be angled upwards to prevent solids from flowing out while allowing gas to flow through. Alternatively, the gas-solids partition 116 may be a wall comprising a distribution of straight or angled slits, holes, tubings, or combinations thereof.

Now referring to FIG. 7, in another embodiment, the gas-solids partition 116 may be above the tapered section of the first reactor 100 that is formed by an outer wall 126. The reaction chamber 112 may be separated from the gas exit chamber 114 by the gas-solids partition 116, and the reaction chamber 112 may be formed by the gas-solids partition 116 and an outer wall 118 that extends beyond the outer radius of the reaction chamber 112. The gas flows out of the first reactor 100 above the tapered transition section 147 may avoid local fluidization. The height of the gas-solids partition 116 may be determined by, for example, the size of the first reactor 100, gas flow rate in the reactor, solid particle properties, cost, and other like properties of the system.

In some embodiments, as shown in FIG. 8, the gas-solids partition 116 may comprise an array of slanted plates 129 with gaps between each plate. The plates 129 may be arranged such that the openings of the gaps are faced towards the direction of solids flow 128. In one embodiment, the width of the gap may be smaller than the diameter of the solid particles, but still allow for reaction product gases 122 and/or sealant gas 512 to pass through.

In another embodiment shown in FIGS. 9 and 10, the first reactor 100 may comprise one or more gas disengagement areas 145. As used herein, a gas disengagement area is any area defined at least partially by an interface 181 between solid particles 128 and gases 122 exiting the first reactor 110. Referring to the embodiment of FIGS. 9 and 10, multiple gas disengagement areas 145, where the solid particles define the bottom boundary of each disengagement area 145 are positioned inside of the first reactor 100. Exiting gases, such as sealant gas 512 and reaction product gases 122 may flow out of the area comprising the flow of solid particles 128 and into the gas disengagement areas 145. The other boundaries of the gas disengagement areas 145 may be defined by internal structure walls 134, which may, as shown in FIG. 9, comprise gas-solids partitions 116. The internal structure walls 134 comprising gas- solids partitions 116 may also allow for reaction product gases 122 and sealant gas 512 to flow out of the reaction areas comprising solid particles and into the gas disengagement areas 145. In another embodiment shown in FIG. 10, the internal structure walls 134 are impervious to gases and do not allow for gases to pass through, and the reaction product gases 122 and sealant gas 512 must pass through the solid particles interface 181 to enter the gas disengagement areas 145.

Again referring to FIGS. 9 and 10, each gas disengagement area 145 may be attached to an exit channel 132 (not depicted in FIG. 9) leading to the gas outlet 120 of the first reactor 100. As such, the gases of the first reactor 100 may flow out of the first reactor 100 once gathered in the gas disengagement areas 145. In one embodiment, the gas disengagement areas 145 may be above the tapered transition section 147, and as a result, reaction product gases 122 may separate from solid particles prior to entering the tapered transition section 147.

As shown in FIGS. 11A and 11B, the internal structural walls 134 may be any shape that does not disrupt the smooth flow of solid particles, such as, but not limited to, cones, pyramids, cone or pyramids with straight section below, triangular prisms, rectangular prisms, or other more complex shapes. The design, arrangement and distribution of the internal walls may be determined by the size of the reduction reactor, gas flow rate in the reactor, particle properties, cost, and other like properties of the system. In one embodiment, the top of the internal structure walls 134 may be generally shaped as a cone whose angle may be larger than the repose angle of the solid particles so that smooth movement of solids may be not disrupted. One or more gas disengagement areas 145 may be present, based on the size of the first reactor 100, gas flow rate in the reactor, particle properties, cost and other like properties of the system. It may generally be desired that the total cross-sectional area of the cones may be large enough such that the gas velocity in the cone may be less than the minimum fluidization velocity. Referring now to FIGS. 11A and 11B, which shows top view of internal gas disengagement areas 145, the gas disengagement areas 145 may be arranged in a number of formations. For example, as shown in FIG. 11A, the gas disengagement areas 145 may be on a common vertical plane, or alternatively, as shown in FIG. 11B, the gas disengagement areas 145 may be on multiple vertical planes.

Now referring to FIGS. 12A, 12B, and 12C, internal gas disengagement areas are depicted that may be positioned in the first reactor 100. The exit channels 132 may be connected to the internal structure walls 134 from top, side or bottom, referring to FIGS. 11 A, 11B, and 11C, respectively. It may be generally desired that some distance be provided between the bottoms of the gas disengagement areas 145 to the top of the internal structure walls 134 to ensure that solids particle will not be entrained by the gas flow. In yet another embodiment, now referring to FIG. 13, the gas disengagement areas 145 may be defined by an expanded reactor section 149 that is wider than the upper external wall 151 of the first reactor 100. The expanded reactor section 149 may be wider than the upper external wall 151 and the top of the expanded reactor section 149 may partially overlap with the upper external wall 151 in the horizontal plane. Thus, the solid particles may flow down through the section of the first reactor defined by the upper external wall 151 and fall down into the expanded reactor section 149 forming a gas disengagement area 145.

The expanded reactor section 149 may be positioned at or near the bottom of the first reactor 100 but above the tapered transition section 147. The annular space defining the gas disengagement areas 145 between the upper external wall 151 and expanded reactor section 149 separates the gas phase from the solid phase. The gas outlet 120 of the first reactor 100 may be coupled to the expanded reactor section 149 but spaced from the solid particles interface 181 to avoid solids entrainment. The cross sectional area of the expanded reactor section 149 should be sufficiently sized to provide proper gas-solids separation.

In still another embodiment shown in FIG. 14, the first reactor 100 may comprise one or more gas disengagement areas 145 that are defined by exterior chambers 183. The exterior chambers 183 may be connected to the upper external wall 151 of the first reactor 100 by solids inlet pipes 185 and may be connected to the first connection 600 by solids return pipes 130. The exterior chambers 183 may be installed and connected between the bottom of straight section the upper external wall 151 and the connection segment 610 of the first connection. The gases of the first reactor, as well as some solid particles flow through the inlet connector from the main reactor area of the first reactor, wherein the solids separate from the gas by gravity or other pressure control. The solid particles may flow into the first connection 600 through the solids return pipe 130, while the gases, such as sealant gas 512 and reaction product gases 122 flows to the gas outlet 120. One or more exterior chambers 183 may be installed, based on the size of the first reactor 100, gas flow rate in the reactor, particle properties, cost, and other properties of the like in the system.

In one embodiment, solids circulation rate may be controlled by a solids circulation device 400 that may be positioned as a device of the first connection 600. The solids circulation device 400 may control the solids circulation rate and may prevent gas mixing between the first reactor 100 and the second reactor 200. An L-valve, J-valve, or H-valve, illustrated in FIGS. 15A, 15B, and 15C, respectively, may be utilized as the solids circulation device 400 to control the solids circulation rate and prevent gas mixing between the reactors. The solids circulation device 400 comprises one or more gas inlets 410 which may push solids towards a desired direction. The direction of the gas inlets may determine the direction of flow of the solids flow 128. The shape of the solids circulation device 400 may both serve to, in conjunction with the gas inlets 410, physically block mixing between the gases of the first reactor 100 and second reactor 200. In addition, the pipe shapes may assist in moving solids in the first connection into a bottom area of the second reactor. In one embodiment, referring to FIGS. 16 and 17, the second connection 700 may comprise a particle makeup device 950. However, the particle makeup device 950 may be positioned on any part of the first connection 600 or second connection 700. Generally, the particle makeup device 950 operates to add particles from another part of the reactor system 150 or from outside the reactor system, adding new particles in place of removed particles, into a desired location in the reactor system. The particle makeup device 950 may generally comprise a solids inventory vessel 760 which may store solid particles for entrance into the system, and a set of valves 755 that act as a lock hopper when the said reactor system may be operated at elevated pressure. The connection segment 750 may be coupled to a connection segment 740 of the reactor system. The particle makeup device 950 may further comprise a solids metering/flow control device to monitor solids flow. In one embodiment, the particle makeup device 950 is coupled to a connection segment 740, which delivers solids to the first reactor 100. In another embodiment, as shown in FIG. 17, the particle makeup device 950 may be positioned on top of the first reactor 100. In one embodiment, the connection segment 750 of the solids makeup device 950 may be the same length as the connection segment 740 of the second connection 700 inserted into the first reactor 100 so that the solid particles level in the first reactor 100 will be maintained at the top of solid particle stack 753 in the first reactor 100. The makeup solids from the particle makeup device 950 mix with re- generated solid particles in the top section of the first reactor 100. In some embodiments, the particle makeup device 950 may serve as measuring device of the solids circulation rate in the reactor system 150. In the particle makeup device 950 of in FIG. 16, by arranging the angle of inclination and diameter of the connection segments 740, 750, the solids flow rates in the two pipes 740, 750 may be the same. In the particle makeup device 950 described in FIG. 17, by arranging the length, diameter, and/or location of the connection segments 740, 750, the solids flow rates of the two segments 740, 750 may be proportional to the ratio of their cross-sectional areas. The solids circulation rate in the chemical looping system may be obtained with various types of solids inventory measuring methods, such as, in cold (non operational temperature) conditions, weight change over a time period or observing the solids level change through a transparent screen in the solids storage tank. The solids makeup device 950 may be interlinked with the bed height control device for the first reactor 100 such that the overall solids inventory within the said reactor system may be maintained within a desired range.

In another embodiment, pressure control devices (not shown) may be installed on one or more of the gaseous outlets. In some embodiments, a pressure control valve may be installed in series with a back pressure regulator to maintain the pressure of the reactor system and adjust the gaseous outlet pressure when necessary. The back-pressure regulator may be used to build up the majority of the pressure whereas the pressure control valve may be adjusted to achieve desired pressure distributions within the said reactor system.