WO2003008091A1

WO2003008091A1 - Regenerative devices and methods

Info

Publication number: WO2003008091A1
Application number: PCT/US2001/022726
Authority: WO
Inventors: Melanius D'souza
Original assignee: D Souza Melanius
Priority date: 2001-07-18
Filing date: 2001-07-18
Publication date: 2003-01-30

Abstract

The present invention is directed to a method and apparatus for directing process fluids through regenerative systems (RD1 and RD2) using a multi-port valve assembly (40C). More than one multi-port valve assembly can be used in a regenerative system to provide for parallel flow or counterflow of the process fluids within the regenerative system. The regenerative systems can be used as regenerative thermal oxidizers, regenerative catalytic oxidizers, volatile organic compound concentrators, reversible chemical reactors and regenerative heat exchangers.

Description

REGENERATIVE DEVICES AND METHODS

FIELD AND BACKGROUND OF THE INVENTION

The present invention is directed to methods and devices for processing fluids in energy conservation and environmental pollution control applications using regenerative techniques.

Regenerative systems have long been used in energy conservation and environmental equipment. Regenerative systems are also used for concentrating pollutants in dilute air streams. Regenerative techniques may be used with reversible chemical reactions. Many of the regenerative systems described above suffer from cross-leakage and capacity limitations.

Therefore, it will be apparent that a need exists for a means of controlling the flow of air through individual regenerative compartments of regenerative devices while providing relatively high destruction, transfer or conversion efficiencies, easy installation, and relatively large flow capacities.

SUMMARY OF THE INVENTION

One aspect of the present invention provides an endless belt valve, which can be used with regenerative systems. The endless belt valve has an endless belt, which is provided with flow openings at predetermined positions. The lower surface of the belt is located adjacent to flow opening on plenums, which contain the process fluids. The upper surface of the belt is located adjacent to fluid flow ports, which supply the process fluid to or remove the process fluid from the regenerative compartments of the regenerative system. As the belt is moved, the openings on the belt line up with selected ports to allow or block the flow of the fluid between the plenums and the selected regenerative compartments. The endless belt used in the above described embodiments can be made of metallic or non-metallic materials. Further the endless belt can be configured as a single layered belt or a composite belt made of multiple layers of different materials.

In one embodiment of the invention, an endless belt valve which controls the flow of two process fluids through two regenerative compartments is used. In yet another embodiment of the invention, the endless belt valve controls the flow of three process fluids through six regenerative compartments. These embodiments are described as examples of the general principles of the endless belt valve of the present inventio , which can be used with any number of process fluids and any number of regenerative compartments.

In a further embodiment of the invention, two endless belt valves are used, one on each end of the regenerative compartments, to control the flow of the process fluids through the regenerative system. The endless belt valves can be configured so that the process fluids can flow either in a co-current flow mode or a counter-flow mode within the regenerative compartments. This regenerative system is particularly useful as a regenerative heat- exchanger or a VOC (volatile organic compound) Concentrator. A further embodiment of the above system uses energy transfer devices within the regenerative material in the regenerative compartments for use of the regenerative system as a Regenerative Thermal Oxidizer or a Reversible Chemical Reactor.

Yet another modification of the invention incorporates catalysts within the regenerative materials for use of the system as a Regenerative Catalytic Oxidizer. Yet another embodiment uses a common endless belt valve to control the flow of fluids at both ends of the regenerative compartments. A further embodiment uses a common drive mechanism to move the two endless belt valves. A different embodiment incorporates a common combustion chamber at the second end of the regenerative compartments for use of the system as a Regenerative Thermal Oxidizer. A variation of this embodiment further incorporates catalysts within the regenerative materials for use of the system as a Regenerative Catalytic Oxidizer.

Still further advantages of the invention will be apparent from the following drawings and description in which similar features have been identically numbered.

BRLEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional elevational representation showing a simplified embodiment of the regenerative system according to the present invention which uses an endless flexible belt as a flow control means and which is adapted to the flow of two process fluids into two regenerative compartments.

FIG. 2 is an exploded perspective representation of the regenerative system of Fig. 1.

FIG. 3A is a dis-assembled plan representation of the Multi-Port Valve Assembly used in the regenerative system of Fig. 1.

FIGS. 3B,3C, and 3D, are assembled "freeze-frame" plan representations of a portion of the endless belt Fig. 1 during its operation. FIG. 3E is another assembled "freeze-frame" plan representation of a portion of the endless belt Fig. 1 A whose flow zones overlap the fluid ports of both regenerative compartments.

FIGS. 4A to 4F are different representations of sealing mechanism used to minimize the passage of fluids between stationary and moving parts in the regenerative system according to the present invention.

FIG. 5 A is a sectional elevational representation showing a simplified embodiment of the regenerative system according to the present invention which uses two endless flexible belts on the first end of the regenerative compartments and which is adapted to the flow of three process fluids into six regenerative compartments.

FIG. 5B is a sectional side-elevational representation of the regenerative system of Fig. 5A.

FIG. 6 A is a plan representation of the endless belts used in the regenerative system of Fig. 5A.

FIG. 6B is a plan representation of the fluid plenums and the fluid ports of the regenerative compartments of Fig. 5A.

FIGS. 6C to 6F are assembled "freeze-frame" plan representations of a portion of the endless belts shown in Fig. 6A during the operation of the regenerative system of Fig. 17A.

FIG. 7A is a sectional elevational representation showing a simplified embodiment of the regenerative system according to the present invention which uses two endless belts , one each on the first and second ends of the regenerative compartments and which is adapted to the flow of two process fluids into six regenerative compartments , and which is further adapted for use as a regenerative heat-exchanger.

FIG. 7B is a sectional side-elevational representation of the regenerative system of Fig. 7A.

FIG. 8 is the regenerative system of Fig. 7A which is adapted for use as a regenerative NOC Concentrator.

FIG. 9 is the regenerative system of Fig. 7A which is adapted for use as a Regenerative Thermal Oxidizer.

FIG. 10 is the regenerative system of Fig. 7 A which is adapted for use as a Regenerative Catalytic Oxidizer.

FIG. 11 is the regenerative system of Fig. 7 A which is adapted for use as a Regenerative Chemical Reactor.

FIG. 12A is a sectional elevational representation showing a simplified embodiment of the regenerative system according to the present invention which uses one endless belt on the first end of the regenerative compartments and which is adapted to the flow of three process fluids into six regenerative compartment , and which has a common combustion chamber in fluid communication with the second ends of the regenerative compartments for use as a Regenerative Thermal Oxidizer.

FIG. 12B is a sectional side-elevational representation of the regenerative system of Fig. 12A.

FIG. 13 is the regenerative system of Fig. 12A which incorporates a catalyst for use as a Regenerative Catalytic Oxidizer.

FIG. 14A is the the regenerative system of Fig. 7a which uses one common endless flexible belt on the first and second ends of the regenerative compartments.

FIG. 14B is the regenerative system of Fig. 7A which uses two endless belts with a common drive mechanism.

FIG. 15 is a sectional elevational representation showing a simplified embodiment of the regenerative system of Fig. 12A further incorporating a clean-out chamber which utilizes thermal bake-off for continuous on-line cleaning of the endless belt.

FIG. 16A is a sectional elevational representation of another embodiment of the clean out chamber of Fig. 15 which utilizes pressurized cleaning fluids or solids for continuous online cleaning of the endless belt.

FIG. 16Bis a sectional elevational representation of another embodiment of the clean out chamber of Fig. 15 which utilizes stationary cleaning brushes for continuous on-line cleaning of the endless belt.

FIG. 16C is a sectional elevational representation of another embodiment of the clean out chamber of Fig. 15 which utilizes rotating cleaning brushes for continuous on-line cleaning of the endless belt.

FIG. 17 is a sectional elevational representation showing two of the regenerative systems of Fig. 7A arranged to share a common belt.

FIG. 18 is a sectional elevational representation showing the regenerative system of Fig. 7A which uses an open flexible belt. DEJAILED DESCRIPTION OF THE INVENTION

Figures 1, 2, 3 A, 3B, 3C, and 3D show an embodiment of regenerative system 1 of the present invention wherein two process fluids, A and B, are contacted with regenerative material 14 in two regenerative compartments, RDl and RD2. Figure 2 is an exploded perspective view of regenerative system 1 of Figure 1.

As used herein, the term "regenerative materials" includes all materials which can assume a first operating state and a second operating state by the imposition of external influences. The two operating states may be thermodynamic, physical, or chemical states. There may also be intermediate operating states between the two operating states. For example, regenerative materials can be heat-sink materials which can transfer and store heat upon contact with a hot fluid and release the stored fluid upon contact with a cold fluid. The first operating state is an initial cold state of the operating cycle and the second operating state is the final hot state of the operating cycle. The heat-sink material goes through intermediate hot and cold states between the two operating states. In this case, the external influences are the hot and cold fluids, which cause a thermodynamic change in the regenerative materials.

Alternatively, regenerative materials can be any material capable of adsorbing or desorbing a chemical species upon change of thermodynamic operating conditions such as temperature, pressure, or concentration. For example, a regenerative adsorption material adsorbs or desorps a chemical species from a gas-mixture upon change in operating temperature or pressure or concentration of the gas-mixture in contact with the regenerative adsorption material. The first operating state is an initial "un-loaded" state of the operating cycle wherein the regenerative material is relatively free of VOCs. The second operating state is the final "loaded" state of the operating cycle wherein VOCs are adsorbed on the material. The adsorption material goes through intermediate "loaded" and "unloaded" states between the two operating states. In this case, the external influences are the higher VOC- concentration adsorbing fluids and the relatively VOC-free desorbing fluids, which cause an adsorption related thermodynamic change in the regenerative materials. Alternatively, a higher pressure adsorbing fluid and a lower pressure desorbing fluid could be the external influences. Yet further, a lower temperature adsorbing fluid and a higher temperature desorbing fluid could be the external influences.

As yet another alternative, regenerative materials can also include materials which change their properties in a chemical reaction but which can be reverted back to their initial state by at least one subsequent chemical reaction. An example of a chemically regenerative material is copper oxide which changes its state to copper sulfate under a first set of operating conditions and is later re-converted back to copper oxide under a second set of operating conditions. In this example, the copper oxide represents the first operating state of the regenerative material and the copper sulfate represents the second state of the regenerative material. Again, there may or may not be intermediate reactions between the first operating state and the second operating state. In this case, the external influences are the chemical reactions, which change the state of the regenerative material.

Examples of regenerative heat-sink media include structured and random packing made of metallic or non-metallic substances. Structured heat transfer media include stacked brick, stacked tubes, extruded monolith blocks with fluid flow passages, or assembled monolith blocks with fluid flow passages such as the MLM (TM) blocks from Lantec Products Inc. Random packing includes balls, randomly dumped rods, intallox saddles, berl saddles, raschig rings, etc. The regenerative heat- sink media can be made of metallic substances or of non-metallic substances. The regenerative heat-sink material can also include liquids and phase-change capable solids such as molten salts, which store heat energy in the form of latent heat of fusion.

Examples of regenerative adsorption media include granulated activated carbon (GAC) or zeolites or desiccant material, in granular form or coated on suitable carrier substrates or as structured elements.

Example of chemically reversible materials include copper oxide used for the reduction of sulfur-dioxide and oxides of nitrogen from flue-gases. A detailed description of a regenerative copper oxide process for the reduction of sulfur-dioxide and oxides of nitrogen from flue-gases is described by Chen and Yeh in an article in Environmental Progress, Volume 17, No. 2 (Summer 1998), Pages 61-69.

Regenerative materials can also include those that need an external energy source to bring them to an activated state for adsorption, catalysis, or chemical reaction. Examples of external energy sources include electromagnetic waves, light waves, atomic particle beams, etc. An example of such a material is Titanium Oxide which when exposed to UN light assumes an activated state and reverts back to its normal un-activated state upon removal of the UN light source. Each of the class of regenerative materials described above can be used alone or in combination with each other in the regenerative system 1 of Fig. l.Each of the regenerative compartments, RDl and RD2, has two fluid passage ports 18A and 18B located in their lower ends 15. Process fluid A is supplied to regenerative compartment RDl and RD2 through identical fluid passage ports 18A, which are located in the lower end 15 of each regenerative compartment RDl and RD2. Process fluid B is removed from regenerative compartment RDl and RD2 through fluid passage ports 18B which are also located in the lower end 15 of each regenerative compartment RDl and RD2. Fluid passage ports 18A and 18B are in fluid communication with fluid plenums 70A and 70B for process fluids A and B respectively. Fluid plenum 70A is provided with a fluid inlet 90A for the supply of process fluid A. Fluid plenum 70B is provided with a fluid outlet 90B for the removal of process fluid B. While the fluid plenums are shown as open tubs in Figure 2, they could also be closed ducts with inlets or outlets, which match the fluid flow ports of the regenerative compartments.

A solid endless belt 40C is located between regenerative compartments RDl and RD2 and plenums 70 A and 70B. Solid endless belt 40C has two sets of flow-permeable flow zones 45A and 45B located on it. The flow passages in the flow zones can be configured as a single large opening in the endless belt or as perforations within the flow zone area. Flow zones 45 A selectively allow for the passage of fluid A from fluid plenum 70 A to regenerative compartment RDl or RD2 when they are overlapped with the fluid inlet port 18A of regenerative compartment RDl or RD2 respectively. Flow passage zones 45B selectively allow for the passage of fluid B from regenerative compartment RD2 or RD 1 when they are overlapped with the fluid outlet port 18B of regenerative compartment RD2 or RDl respectively. As shown in Figure 2, drive pulley 50B (driven by drive motor 160) and idler pulleys 60B move the endless belt 40C so that flow zones 45A and 45B selectively overlap with fluid ports 18A and 18B to enable fluids A and B to alternately pass through regenerative compartments RDl and RD2 as described above. Motor 160 could be a continuously revolving or a periodically advanced ratchet type device.

Endless belt 40C can be made of a flexible, heat-resistant, wear-resistant, non- permeable, NOC-resistant material such as spring-steel or stainless-steel or carbon steel or aluminum or other suitable metal or metallic alloy. Metallic belts suitable for use in the above application are readily available from a number of commercial suppliers. Alternately, endless belt 40C can also be made of a non-metallic material such as Neoprene, Butyl, EPDM, Fluoroelastomer, Niton (TM), Teflon (R) etc. Other refinements such as composite belts consisting of layers of any of the materials described above and belts incorporating filters in their flow passage zones may be used.

To control the leakage of fluids A and B, the fluid inlet and outlet ports 18A and 18B and the fluid plenums 70A and 70B can be provided with fluid leakage controls seals. For example, a seal can be provided along the periphery of fluid inlet port 18 A. The seal can also be provided along the periphery of the open top of tub-shaped fluid plenum 70 A shown in Fig. 2. Alternately, if the fluid plenums are shaped as closed ducts as described above, the seals can be provided along the periphery of each of the inlets or outlets. The seal is designed to reduce the leakage of fluid A while providing sliding contact with endless belt 40C. Examples of suitable seals that could be used are shown in Figures 4A to 4F. Figures 4A and 4B shows examples of gap or labyrinthe seals. Figures 4B, 4C, and 4D show examples of contact seals with and without spring assistance. Figures 4E and 4F show examples of wiper seals. Figures 4C, 4D, and 4F show examples of air seals.

Further leak control can be achieved by providing lips 80 around the peripheries of fluid ports 18A and 18B of regenerative compartments RDl and RD2. Similar lips 80 can also be provided around the fluid flow inlets and outlets of plenums 70A and 70B. Figure 3 A shows a disassembled view of the endless belt 40C , without the drive system, used in the regenerative system of Fig. 1 in which endless belt 40C is shown separated from fluid plenums 70 A and 70B and regenerative compartments RDl and RD2. Figures 3B, 3C, and 3D are "freeze-frame" sequential representation of the positions of flow passage zones 45 A and 45B relative to fluid ports 18A and 18B of regenerative compartments RDl and RD2 during the operation of regenerative system 1. In Figure 3B, flow passage zone 45 A is an overlapping position with fluid inlet 18A of regenerative compartment RDl while neighboring flow passage zone 45B is an overlapping position with fluid outlet 18B of regenerative compartment RD2. Simultaneously, the adjacent solid zones 48 of endless belt 40C are in an overlapping position with fluid inlet 18A of regenerative device RD2 and fluid outlet 18B of regenerative device RDl. Thus in this first position of endless belt 40C, process fluid A is allowed to flow from fluid plenum 70A to regenerative compartment RDl to contact the regenerative material 14 therein while fluid B is allowed to flow from regenerative compartment RD2 to fluid plenum 70B after contacting the regenerative material 14 therein.

Fig. 3C is another "freeze-frame" representation of endless belt 40C which shows an intermediate operating position of regenerative system 1 after endless belt 40C has been moved to the left. In this second position, solid zones 48 overlap fluid ports 18A and 18B of both regenerative compartments RDl and RD2. Thus contact of both process fluid A and process fluid B with regenerative material 14 in regenerative compartments RDl and RD-2 is temporarily shut-off.

Fig. 3D is another "freeze-frame" representation of endless belt 40C which shows the next operating position of regenerative system 1 after endless belt 40C has been moved further to the left. In this second position, flow passage zone 45A overlaps fluid port inlet port 18A of regenerative compartment RD2 and flow passage zone 45B overlaps fluid port outlet port 18B of regenerative compartment RD2 while solid zones 48 overlap inlet port 18A of regenerative compartment RDl and outlet port 18B of regenerative compartment RD2. Thus contact of fluid A with regenerative material 14 in regenerative compartment RD2 is now enabled while contact of fluid B with the regenerative material 14 in regenerative compartment RDl is also enabled. Therefore, by moving endless belt 40C continuously to the left, successive flow passage zones 45A and 45B are overlapped with fluid ports 18A and 18B of regenerative compartments RDl and RD2 as described above. Thus process fluids A and B are alternately contacted with the regenerative material 14 in regenerative compartments RDl and RD2 respectively.

The regenerative system of Fig. 1 is useful for transferring heat from a hot gas stream to a cold gas stream. Process fluid A could be a hot gas stream. Initially, endless belt 40C could be positioned as shown in Fig 3B so that process fluid A can be pushed through regenerative compartment RDl to heat the previously cooled regenerative material 14 while itself being cooled. Endless belt 40C can then be moved to the position shown in Fig 3D as described above so that process fluid B can be pushed through regenerative compartment RDl to cool the previously heated regenerative material 14 while itself being heated. To eliminate the momentary stoppage of the flow of fluid A in the regenerative system of Figure 1, the width of flow zones 45 A on endless belt 40C can be made larger so that they straddle both inlet ports 18A of regenerative compartments RDl and RD2 while in the position shown in Figure 3C. Similarly, the width of flow zones 45B on endless belt 40C can be made larger so that they could straddle both outlet ports 18B of regenerative compartments RDl and RD2 to eliminate the momentary stoppage of the flow of fluid B. This configuration is shown in Figure 3E. It will be obvious that a certain amount of cross contamination of fluids A and B can occur with this configuration. This cross-contamination can be eliminated by providing additional regenerative compartments which are isolated or purged for a brief period of time during the transition from fluid A to fluid B.

By now, it will be apparent to one of ordinary skill in the art that any combination of fluids and regenerative devices can be used in regenerative system 1. Also for design and constructional reasons, flow passage zones 45 can be provided on more than one endless belt 40C. For example, if three process fluids A, B, and C are to be processed, flow passage zones 45A and 45B can be located on a first endless belt 40C1 and flow passage zones 45C can be located on a second flow control means 40C2. Such an arrangement may be necessary in cases where fluids A, B, and C have different physical or chemical characteristics. For instance, in the above example, if process fluid C is corrosive, then endless belt 40C2 can be made of Teflon while endless belt 40C1 can be made of a less expensive material such as steel. The use of two endless belts will not affect the operation of regenerative system 1 if the movement and positions of the flow passage zones, 45 A and 45B, on endless belt 40C1 is aligned with the movement and positions of the flow passage zones 45C on endless belt 40C2 so that the two endless belts operate similar to a single endless belt which contains flow passage zones 45 A, 45B, and 45 C on it.

The previous example assumed that a regenerative compartment is continuously contacted by a process fluid. However, it is not necessary that the regenerative material in the regenerative compartment be continuously contacted with a fluid. By omitting a flow passage zone 45 on flow control means 40, a regenerative compartment can experience an idle period wherein no fluid contacts the regenerative material within it. Thus a "blind" flow passage zone 45 in which no fluid passages are present can be incorporated on flow control means 40 so that no fluid can pass through it during a "contact" period. Thus the regenerative compartment will experience an idle period before it is again contacted with a process fluid. Such idle periods may be necessary for process reasons or to reduce cross-contamination of process fluids during operation of regenerative system 1.

Figures 5 5B , 6A, 6B, 6C, 6D, 6E and 6F show another embodiment of a regenerative system 1 wherein regenerative system 1 contains six regenerative compartments RDl, RD2, RD3, RD4, RD5, and RD6 which are selectively contacted by process fluids A, B, and C respectively. Figure 5 A is a front elevational representation. Figure 5B is a side elevational representation. The regenerative system of Figures 5 A and 5B uses two endless belts designated as 40C1 and 40C2 respectively. The first belt 40C1 contains flow passage zones 45 A. The second belt 40C2 contains flow passage zones 45B and 45C. The two belts are arranged so the flow passage zones 45A, 45B, and 45C follow the sequence required to create an operating cycle. Thus the positions of flow passage zones 45A, 45B, and 45C would be equivalent to their positions on an equivalent single belt.

The operation of regenerative system 1 of Figure 5 A is described in Figures 6A, 6B, 6C, 6D, 6E, and 6F. A cross-sectional representation of regenerative system 1 which shows fluid plenums 70A, 70B, and 70C and fluid passage zones 45A, 45B, and 45C is also shown in Figure 5B.. For clarity, the return loop of the belt and the drive mechanism 50 is not shown in Figure 5B. Also for clarity, the flow passage zones 45A, 45B, and 45C in Figure 5B are shown to be simultaneously exposed to the same regenerative compartment resulting in process air streams A, B, and C all simultaneously entering the regenerative compartment. However, in actual practice, flow passage zones 45 A, 45B, and 45C are located as shown in Figure 6C so that only one of the process fluids can enter each regenerative compartment at any time.

Following the descriptional narrative used in describing previous embodiments of the regenerative system 1, Figure 6 A shows a representational view of endless belts 40C1 and 40C2 showing the location of fluid passage zones 45 A, 45B, and 45C. It should be noted that the width of the solid portion of endless belts 40C1 and 40C2 between adjacent flow passage zone 45 A and 45 C and between adjacent flow passage zone 45 C and 45B should be at least one-half of the width of fluid ports 18A and 18B respectively in the regenerative compartments to prevent cross-mixing of fluids A and B. In Figure 6 A, the width of the solid portions 48 of endless belt 40C between adjacent flow passage zone 45A and 45C and between adjacent flow passage zone 45C and 45B is shown equal to the width of fluid ports 18A and 18B respectively to prevent cross-mixing between fluids A and C and between fluids C and B. Furthermore, the total width of adjacent flow passage zones (45 A, 45 A} is shown to be equal to twice the width of fluid port 18 A. The adjacent flow passage zones {45 A, 45 A} are shown to be located close to each other to reduce the amount of pressure and flow fluctuation that may occur when flow control means 40C is moved. In practice, a single flow passage zone with width equal to two times the width of opening 18 A may also be used instead of the two adjacent flow passage zones {45 A, 45 A} without affecting the operation of the regenerative system. Other combinations of sizes of fluid passage zones and distances between the passage zones are possible.

Figure 6B shows a representational view of the fluid plenums 70A, 70B and 70C and regenerative compartments RDl, RD2, RD3, RD4, RD5, and RD6. Figures 6C, 6D, 6E, and 6F are "freeze-frame" sequential representations of the positions of flow passage zones 45 A, 45B, and 45 C relative to fluid ports 18 A, 18B, and 18C on the six regenerative compartments during the operation of regenerative system 1. For clarity, pulleys 50B and 60B are not shown in these figures.

In Figure 6C, flow passage zones 45A are shown in an overlapping position with fluid ports 18A of regenerative compartments RD5 and RD6 respectively, while flow passage zones 45C are shown in an overlapping position with fluid ports 18C of regenerative compartments RDl and RD4 respectively, and flow passage zones 45B are shown in an overlapping position with fluid ports 18B of regenerative compartments RD2 and RD3 respectively. Thus in this first position of endless belts 40C1 and 40C2, process fluid A contacts the regenerative material 14 in regenerative compartments RD5 and RD6, and process fluid B contacts the regenerative material 14 in regenerative compartments RD2 and RD3 while process fluid C contacts the regenerative material 14 in regenerative compartments RDl and RD4. As noted above, flow passage zones 45 A are sized so that there is no interruption of flow of process fluid A as first flow passage zone 45 A is moved from inlet port 18A of regenerative compartment RD6 to inlet port 18A of regenerative compartment RD5. Similarly, flow passage zones 45B are sized so that there is no interruption of flow of process fluid B as first flow passage zone 45B is moved from outlet port 18B of regenerative compartment RD3 to outlet port 18B of regenerative compartment RD2.

Figure 6D is another "freeze-frame" representation which shows another operating position of regenerative system 1 after endless belts 40C1 and 40C2 have been moved to the left. Following the above description, it will be seen that in this second position of endless belts 40C1 and 40C2, process fluid A contacts the regenerative material 14 in regenerative compartments RD4 and RD5, and process fluid B contacts the regenerative material 14 in regenerative compartments RDl and RD2 while process fluid C contacts the regenerative material 14 in regenerative compartments RD3 and RD6. Similarly, in the "freeze-frame" representation in Figure 6E, it can be seen that process fluid A contacts the regenerative material 14 in regenerative compartments RD3 and RD4, and process fluid B contacts the regenerative material 14 in regenerative compartments RDl and RD6 while process fluid C contacts the regenerative material 14 in regenerative compartments RD2 and RD5. Similarly, in the "freeze-frame" representation in Figure 6F, it can be seen that process fluid A contacts the regenerative material 14 in regenerative compartments RD2 and RD3, and process fluid B contacts the regenerative material 14 in regenerative compartments RD5 and RD6 while process fluid C contacts the regenerative material 14 in regenerative compartments RDl and RD4. Thus it can be seen that successive movement of endless belts 40C1 and 40C2 to the left results in regenerative material 14 in each regenerative compartment , RDl to RD6, being contacted twice by process fluid A, once by process fluid C, twice by process fluid B, and once again by process fluid C to complete an operating cycle for the regenerative system 1 of Figures 5 A and 5B.

The regenerative system of Figure 5 A is particularly useful in a situation such as that described above for Figure 1. If process fluids A and B are reactive with each other, a third inert fluid C can be introduced into the regenerative compartment between process fluids A and B to remove any residual process fluid A or process fluid B prior to the entry of process fluid B or process fluid A. Thus each regenerative compartment will experience two contact periods with process fluid A, followed by a contact period with process fluid C, followed by two contact periods with process fluid B, and finally followed by a contact period with process fluid C.

All of the embodiments of the invention that have been described so far utilize endless belts at one end for flow control of various fluids through selected regenerative compartments for pre-determined periods of time. However a regenerative system can also utilize endless belts at the second ends of its regenerative compartments to control the flow of fluids through individual regenerative compartments.

Figures 7 A and 7B show another embodiment of regenerative system 1 wherein each of regenerative compartments RDl, RD2, RD3, RD4, RD5, and RD6 shown in Figure 5A have a second end which is adapted for fluid communication similar to the first end. For simplicity, this system is shown to only treat fluids A and B. Therefore as shown in Figure 7B, only fluid plenums 70A and 70B are provided. Also for simplicity, only one endless belt 40C is shown. All of the flow passages 45 A and 45B shown in Figure 6A are similarly imposed on single endless belt 40C. Because only two fluids A and B are processed, flow passages 45C shown in Figure 6A are not required to be provided on endless belt 40C. Instead, a solid web is located in its place to totally block off any flow of any fluid to the regenerative compartment during its positioning in the regenerative compartment as shown in Figures 6C to 6F. A second endless belt 40C, which is similar to first endless belt 40C, is located adjacent to the second end of regenerative compartments RDl, RD2, RD3, RD4, RD5, and RD6. Complementary fluid plenums 70A' and 70B', which are similar to fluid plenums 70A and 70B are provided at the second end of the regenerative compartments RDl to RD6 for each fluid A and B respectively.. Endless belt 40C has flow passages 45 and 45B', which are generally coincident with flow passages 45 A and 45B of endless belt 40C. Flow control means 40C and flow control means 40C are further arranged so that individual flow passage zones 45A and 45B in flow control means 40C are aligned with similar flow passage zones 45 A' and 45B in flow control means 40C . Endless belt 40C is moved by a a drive pulley 50B' which can be identical, except for its rotation in an opposite direction , to drive mechanism 50B for endless belt 40C. Hence, drive mechanisms 50B and 50B¹ in regenerative system 1 of Figure 7A, move endless belts 40C and 40C at equal speeds in the same direction relative to fluid plenums 70A, 70B, 70A and 70B". Thus if endless belt 40C moves from right to left between the first ends of regenerative compartments RDl to RD6 and the fluid plenums 70A and 70B , then endless belt 40C also moves from right to left between the second ends of regenerative compartments RDl to RD6 and the fluid plenums 70A and 70B¹. Thus any one of regenerative devices RDl, RD2, RD3, RD4, RD5, and RD6 which is seeing a flow passage zone 45A or 45B at its first end will see a correspondingly matched flow passage zone 45 A' or 45B' at its second end. It is not necessary that flow passage zones 45 A and 45B exactly overlap flow passage zones 45 A⁵ and 45B. As shown in Fig. 7B, they could be on diagonally opposite ends to ensure efficient contact of fluids A and B with regenerative material 14

The supply and removal of process fluids A and B from the regenerative system 1 of Figure 7A can be arranged so that a process fluid can flow either in the same direction (co- current flow) within the regenerative compartment as another process fluid or it can flow in an opposite direction (counter-current flow) to the other process fluid.

In the embodiment of the regenerative system 1 of Figure 7A, each regenerative compartment experiences an idle period followed by two contact periods with fluid A, followed by an idle period, and followed in turn by two contact periods with fluid B before the cycle is repeated.

Any number of process fluids can be used in regenerative system 1 of Figure 7 A. For example, the fluid plenum and endless belt configurations shown in the regenerative system of Figures 5 A, 5B, 6A to 6F could also be used on both ends of the regenerative compartments RDl to RD6 of Figures 7A and 7B. In such a case, the operating cycle of the system would be two periods of flow of fluid A, followed a period of flow by fluid C, followed by a period of flow of fluid B, and further followed by a period of flow by fluid C. Also the flow of any of the process fluids can be arranged so that it is in a co-current -flow configuration with a second process fluid but in a counter-flow configuration with a third process fluid. It is contemplated that regenerative system 1 of Figure 7A and 7B will be particularly useful for energy conservation.

For example, an industrial facility which desires to recover exhaust heat from several exhaust-air streams by heating other process fluids can direct these to a regenerative system similar to regenerative system 1 of Figure 7 A. In this application, regenerative system 1 of Figure 7 A will contain regenerative heat-sink materials 78 for removal and storage and transfer of heat from one process fluid to another. The direction of flow i.e. parallel or counterflow, sequence and contact period of the exhaust and process streams can be individually arranged so that the maximum heat is transferred from the exhaust streams to the process streams. All kinds of arrangements of the number of regenerative compartments, the number of fluids, the contact times, and the flow arrangements (co-current or counter- current) could be used in such a regenerative system.

The regenerative system of Figure 7 A can also be used as a NOC Concentrator by using regenerative adsorption materials as defined above instead of the regenerative heat-sink materials 78. Such a system is shown in Figure 8 in which regenerative heat-sink materials 78 are shown replaced by regenerative adsorption materials 172. The operation of the regenerative system as a NOC Concentrator follows the operational steps described above for the regenerative heat-exchanger shown in Fig. 7 A and will be obvious to a person having ordinary skill in the art.

As an example of the use of such a system, assume that an industrial facility has a polluted NOC containing exhaust stream A. The concentration of the NOCs in process stream A is assumed to be about 10 ppmv. To economically recover the NOCs, it may be necessary that the NOC concentration be at least 100 ppmv. The flow zones on endless belt 40C could be arranged so that there are four flow passage zones 45A for polluted process stream A for each flow passage zone 45B for desorbing process stream B. When polluted stream A is passed through the regenerative system 1 of Figure 8, the NOCs are adsorbed on to the regenerative adsorption media 172. A relatively NOC-free process fluid B is then passed counter-current to process fluid A through the NOC-loaded regenerative adsorption media 172. Generally, process stream B has a tenth of the volumetric flow-rate of process stream A. Therefore, the concentrations of the NOCs in process stream B after the transfer of the NOCs from fluid A to fluid B is approximately 10 times that of the concentrations of the NOCs in process stream A. Process fluid B is then passed to post-treatment processes. Referring now to Figure 8, regenerative compartments RDl, RD2, RD3, RD4, RD5, and RD6 are each filled with regenerative adsorption material 172. NOC containing fluid A is introduced into the regenerative system 1 through inlet 90A on fluid plenum 70A. Assume that endless belt 40C is positioned so that one of its flow passage zone 45 A is aligned with a fluid inlet 18 A of regenerative compartment RDl. As described above with respect to Figure 7A , endless belt 40C is also positioned so that a corresponding flow passage zone 45 A' is aligned with a fluid outlet 18 A' of regenerative compartment RDl. Thus fluid A flows from fluid plenum 70A to fluid plenum 70 A' through regenerative compartment RDl. The NOC in fluid A is adsorbed onto regenerative material 172 in RDl. Thus the concentration of NOCs in fluid A as it leaves fluid plenum 70' is greatly reduced. Similarly, clean process fluid B is introduced into regenerative system 1 through inlet 90B' on fluid plenum 70B¹. Assume that endless belt 40C is now positioned so that one of its flow passage zone 45B' is aligned with fluid inlet 18B' of regenerative compartment RD2. As described above with respect to Figure 7A, endless belt 40C is also positioned so that a corresponding flow passage zone 45B is aligned with a fluid outlet 18B of regenerative compartment RD2. Thus process fluid B flows, counter-flow to process fluid A, from fluid plenum 70B' to fluid plenum 70B. Assume further that regenerative compartment RD2 had previously been contacting process fluid A as described above with respect to RDl. Thus regenerative adsorption materials 172 in RD2 are loaded with NOCs prior to their being contacted with process fluid B. Since process fluid B is relatively free of NOCs, it desorbs the loaded NOCs from regenerative adsorption materials 172 in regenerative compartment RD2. Therefore, the concentration of NOCs in process fluid B as it leaves fluid plenum 70B is increased resulting in concentrated NOC-containing process fluid stream B. As is well known, the desorption of NOCs from regenerative adsorption materials can be accelerated by heating process stream B to a higher temperature at which desorption is facilitated. A temperature regulation device, as described below for Figure 11 , can also be used to maintain the optimum adsorption and desorption temperatures in adsorption material 172 during the adsorption and desorption cycles.

In the above example, the regenerative adsorption materials 172 in any of regenerative compartments RDl to RD6 in regenerative system 1 of Figure 8 contact process fluid A for five contact periods and process fluid B for one contact period. However other configurations of the embodiment of the regenerative adsorption system shown in Figure 8 can also be used without departing from the spirit of the invention. For example, a greater or lesser number of regenerative adsorption compartments can be used. The relative fiowrates of process fluids A and B can also be different from the ten to one ratio described above. Additional purge streams or blind flow passage zones can also be incorporated in the regenerative adsorption system to prevent cross-mixing of process streams from occurring. Such methods are well known to artisans. For example, a regenerative adsorption system can be purged with purging fluid C in between periods of contact with polluted process fluid A and periods of contact with process fluid B respectively.

The regenerative system of Figure 7 A can also be adapted for use as a Regenerative Thermal Oxidizer or Regenerative Catalytic Oxidizer (RCO). An embodiment of regenerative system 1 that is used as a Regenerative Thermal Oxidizer is shown in Figure 9 In this embodiment, the regenerative material 14 used is regenerative heat-sink materials 78 as defined previously in this description. Heating means 120 is provided to heat up the regenerative heat-sink materials 78 in each of the regenerative devices RDl to RD6. Heating means 120 could include fossil fuel combustion devices, electric heater elements, external hot air sources, induction heaters, microwave heaters, infra-red heaters, hot-oil coils, steam coils, external heat-conducting members, heat-exchangers, solar-energy heaters, etc. Figure 9 shows heating means 120 located near the middle of regenerative heat sink material 78. However, as is known, heating means 120 could also be located outside the bed and operated to produce a hot zone near the center of regenerative heat-sink material 78.

As an example, in the Regenerative Thermal Oxidizer shown in Figure 9, the single NOC-containing process stream is divided into two streams, designated as process fluid A and process fluid B which are passed in a counter-flow manner in the regenerative compartments as described above with respect to Figure 7A. Thus, for example, process fluid A can be introduced into regenerative system 1 through fluid inlet 70A and can flow through three regenerative compartments, finally leaving the system through fluid outlet 70A'. Similarly, fluid B can be introduced into regenerative system 1 through fluid inlet 70B' and can flow through the remaining three regenerative compartments, finally leaving the system through fluid outlet 70B.

For operation of the regenerative system 1 of Figure 9, heating means 120 is first activated until the middle section 78M of the regenerative heat-sink bed 78 in each of regenerative compartments RDl to RD6 reaches a temperature greater than the auto-ignition temperature of the NOCs. Process fluids A and B are then allowed to flow through regenerative system 1. As an example, assume endless belts 40C and 40C are positioned so that process fluid A enters regenerative compartment RDl through fluid plenum 70A and leaves regenerative compartment RDl through fluid plenum 70A'. When process fluid A reaches the hot middle section 78M of regenerative compartment RDl, it gets heated to above the auto-ignition temperature of the NOCs contained in it. The NOCs start oxidizing and release heat further raising the temperature of process fluid A. The hot, oxidized process fluid A then flows through the upper section 78U of regenerative compartment RDl . The upper section 78U of regenerative compartment RDl is relatively colder than the oxidized process fluid A. Upper section 78U therefore removes heat from the hot oxidized fluid A and gets heated while fluid A gets cooled. Thus heat is removed from oxidized process fluid A and is recovered in upper section 78U resulting in a high degree of thermal energy recovery.

Now further assume that flow control means 40C and 40C are moved and are now positioned so that process fluid B enters regenerative compartment RDl through fluid plenum 70B' and leaves regenerative compartment RDl through fluid plenum 70B. When process fluid B enters the upper section 78U of regenerative device RDl, it strips some of the previously stored heat from section 78U. Thus process fluid B gets preheated while upper section 78U gets cooled. When process fluid B reaches the hot middle section 78M of regenerative compartment RDl, it gets further heated to above the auto-ignition temperature of the NOCs which start oxidizing and release heat further raising the temperature of fluid B. The hot, oxidized process fluid B then flows through the lower section 78L of regenerative compartment RDl. Lower section 78L of regenerative compartment RDl is relatively colder than oxidized process fluid B. Lower section 78L therefore removes heat from the hot oxidized fluid B and gets heated while fluid B gets cooled. Thus heat is removed from oxidized process fluid B and is recovered in lower section 78L resulting in a high degree of thermal energy recovery.

The above steps provide for the recovery of heat by transferring the stored heat from the upper section 78U or the lower section 78L of regenerative device RDl to its lower section 78L or upper section 78U respectively while facilitating the pre-heating and cooling of process streams B and A.

The process described above with respect to the flow of fluids A and B in regenerative device RDl also takes place in each of the other regenerative devices RD2 to RD6 in regenerative system 1 of Figure 9. Thus the regenerative heat-sink bed 78 in each regenerative device RDl to RD6 alternately contacts fluids A and B resulting in alternate heating and cooling of its upper and lower sections 78U and 78L respectively. The cycles described above are repeated for^' continuous oxidation of the NOCs in the polluted air- stream.

Other configurations can also be used in regenerative system 1 of Figure 9. For example, eight regenerative compartment could be used and purge fluid could be used to flush out the residual NOC-laden air from the inlet zones prior to switch over from fluid A to fluid B and vice versa. The above examples of Regenerative Thermal Oxidizers are not meant to be all-encompassing of the art.

The regenerative oxidizer system described above with respect to Figure 9 can be easily adapted for catalytic oxidation by incorporating catalyst about the middle section 78M of regenerative heat-sink bed 78. An embodiment of regenerative system 1 of Figure 9, which incorporates a catalyst 130 for oxidation of the NOCs at a lower auto-ignition temperature is shown in Figure 10. Catalyst 130 can be coated on heat sink media 78 or can be mixed with the heat-sink materials 78 or can be arranged in layers within the heat-sink materials 78. In any case, catalyst 130 is so located so that it gets heated to its operating temperature by heating means 120 which is shown located within heat sink bed 78. The operation of the catalytic regenerative oxidizer follows the operational steps described above for the Regenerative Thermal Oxidizer system of Fig. 9 and will be obvious to a person having ordinary skill in the art.

While the Regenerative Thermal Oxidizer of Figure 9 and the regenerative catalytic oxidizer of Figure 10 have been shown with heating means 120 only, there may also be situations where the regenerative heat sink bed 78 has to be cooled because excess heat is generated by the oxidation of the NOCs. To maintain a stable operating condition under such circumstances, temperature regulating device 122 which will be described below with respect to Figure 11 can be used instead of heating device 120 shown in Figsure 9 and 10. The temperature regulating device 122 has the capability of adding or removing heat as needed from the regenerative heat sink beds 78 to maintain a stable operating temperature within the heat sink beds.

The regenerative system of Figure 9 can also be easily adapted for use as a Reversible Chemical Reactor. An example of an embodiment of regenerative system 1 that is used as a Reversible Chemical Reactor is shown in Figure 11. In this example, copper oxide supported on alumina substrate material in the form of alumina spheres is used as the chemically reversible material, 174. Each of the regenerative compartments RDl to RD6 in regenerative system 1 of Figure 11 further has a temperature regulating device 122 for controlling the temperature of the chemically reversible material 174 at an optimum temperature for the chemical reaction under consideration. Temperature regulating device 122 could include heating and cooling devices or a combination of heating and cooling devices. The heating devices could include those previously mentioned. Cooling devices could include cooling coils, refrigeration devices, external heat-conducting members, heat-exchangers, thermoelectric cooling devices, cooling fluid injectors, etc. The temperature regulating device 122 of Figure 11 is located so that essentially all of the chemically reversible material 174 is maintained at a uniform optimum temperature for the chemical reaction to take place. However, temperature regulating device 122 can also be located so that only a part of chemically reversible material 174 is heated or cooled as described above. The Reversible Chemical Reactor of Figure 11 is particularly useful for removing pollutants such as sulfur- dioxide and oxides of nitrogen from flue gases generated by industrial and commercial facilities. However, it could also be used for other chemical processes.

As an example, the Reversible Chemical Reactor of Figure 11 could be arranged to contact the reversible chemical material in the regenerative compartments for two periods with a process fluid A, followed by an idle period, followed by contact with process fluid B for two periods, and finally followed by another idle period to complete the operating cycle. In this example, process fluid A is the flue-gas stream mixed with a pre-determined quantity of ammonia for reduction of the nitrogen oxides and process fluid B is an air-methane mixture used for regenerating the copper oxide from its reacted state.

Assume that fluid A is introduced into regenerative system 1 through fluid inlet 70A and leaves regenerative system 1 through fluid outlet 70A' and fluid B is introduced in to regenerative system 1 through fluid inlet 70B' and leaves regenerative system 1 through fluid outlet 70B. Thus the flow of process fluids A and B is counter to each other.

In this example, it is assumed the endless belt 40C and 40C are positioned, as described previously with respect to other two-belt embodiments of regenerative system 1, such that process fluid A enters regenerative compartment RDl through fluid plenum 70A and leaves regenerative compartment RDl through fluid plenum 70 A'. Therefore, flow passage zone 45 A overlaps fluid inlet 18 A and flow passage zone 45 A' overlaps fluid outlet 18 . Using regenerative compartment RDl as an example, temperature regulating means 122 is first activated until chemically reversible material 174 in regenerative device RDl is at a temperature which is suitable for the reducing reaction to be carried out. In this particular example, a reaction temperature of about 400 degrees centigrade is contemplated as the optimum temperature for the chemical reaction.

The flow of process fluid A through regenerative compartment RDl is then started to initiate the reducing reaction wherein the copper oxide in chemically reversible material 174 reacts with the sulfur dioxide and oxygen in the flue gas to form copper sulfate. The copper sulfate and the unreacted copper oxide further act as catalysts to react the oxides of nitrogen with the ammonia and the oxygen in the flue gas to produce nitrogen and water. When enough of the copper oxide is reacted to copper sulfate as evidenced by the decrease in conversion efficiency at fluid plenum 70 A', regenerative compartment RDl is put into an idle mode by moving endless belts 40C and 40C to overlap solid zone 48 and 48' of endless belts 40C and 40C with fluid inlet 18A and fluid outlet 18 . Thus regenerative compartment RDl is isolated from process fluids A and B.

When regenerative compartment RDl is in an idle mode, temperature regulating device 122 is activated to increase the temperature of the reacted regenerative materials 174 in regenerative compartment RDl to a suitable temperature for regeneration of the copper sulfate back to copper oxide. In this example, a temperature of about 450 degrees centigrade is contemplated. When the temperature of reacted materials 174 in regenerative compartment RDl is at the desired temperature, regenerative compartment RDl is put into the regeneration reaction mode by advancing endless belts 40C and 40C to overlap flow passage zone 45B and 45B' of endless belts 40C and 40C with fluid inlet 18B and fluid outlet 18B¹. For optimum conversion, process fluid B is passed in a counter-current manner in regenerative device RDl relative to process fluid A. Therefore, process fluid B enters regenerative system 1 through fluid plenum 70B' and leaves regenerative system 1 through fluid plenum 70B. In the regeneration reaction, the methane in process fluid B converts the copper sulfate in reacted materials 174 in regenerative device 1 back to copper. The copper then reacts with the oxygen in the air in process fluid B to copper oxide, which is the initial state of chemically reversible materials 174.

When enough of the copper sulfate has been regenerated back to copper oxide as evidenced by the decrease in conversion efficiency of the methane at fluid plenum 70 A, regenerative compartment RDl is put into a second idle mode by advancing flow control means 40C and 40C to overlap solid zones 48 and 48' of endless belts 40C and 40C with fluid inlet 18B and fluid outlet 18B'. When regenerative compartment RDl is in an idle mode, temperature regulating device 122 is activated to reduce the temperature of the regenerated regenerative materials 174 in regenerative compartment RDl back to a suitable temperature, contemplated to be about 400 degrees centigrade, in preparation for the reduction reaction as described above. When the temperature of reacted materials 174 in regenerative compartment RDl is at the required temperature, regenerative compartment RDl is put into the forward reaction mode by advancing endless belt 40C and 40C to overlap flow passage zone 45 A and 45 A of endless belt 40C and 40C with fluid inlet 18A and fluid outlet 18 . This completes the entire reducing reaction and regeneration reaction cycle.

The process described above with respect to the flow of process fluids A and B in regenerative device RDl also takes place in each of the other regenerative devices RD2 to RD6. Thus the regenerative materials 174 in each regenerative device RDl to RD6 go through a cycle of first contacting process fluid A to reduce the sulfur dioxide and nitrogen oxides, then being further heated in an idle operating mode to a temperature suitable for the regeneration reaction to take place, then being contacted with process fluid B to regenerate the copper oxide, and finally being cooled down to a temperature suitable for the reducing reaction to take place.

While an equal number of contact periods have been assumed for both process fluid A and B, the contact periods for process fluid A, fluid B, and the idle periods in between fluid contact can be individually adjusted depending on conversion and chemical kinetic considerations.

Other configurations can be used in the Reversible Chemical Reactor described above. For example, 8 regenerative beds could be used and purge fluid could be used to flush out the residual pollutant-laden air from the inlet zones prior to switch over from process fluid A to process fluid B and vice versa. The above example of a Reversible Chemical Reactor is only meant to be illustrative of the method of chemical regeneration. The application of the above example of a Reversible Chemical Reactor can be extended to other reducing-regenerating reactions.

Yet another embodiment of a regenerative system 1 which is used as a Regenerative Thermal Oxidizer and which uses an endless belt at one end only is shown in Figures 12A and 12B. The endless belt 40C has its flow passage zones 45A, 45B, and 45C in the relative positions shown on Figure 6A. In this example , process fluid A represents the NOC containing process air which is to be cleaned in regenerative system 1, process fluid B represents the process air after the NOCs have been oxidized in combustion chamber 140 (described below), and process fluid C represents the fluid used to purge the residual gases from individual regenerative compartments between the passage of the polluted process fluid A and cleaned process fluid B.

As shown in the side elevation representation in Figure 12B , regenerative system 1 includes a set of fluid plenums 70A, 70B, and 70C. Process fluid A is introduced into regenerative system 1 through inlet 90A on fluid plenum 70A, while the cleaned process fluid B is removed from regenerative system 1 through outlet 90B on fluid plenum 70B. Purge process fluid C, is either introduced or removed from regenerative system 1 through outlet 90C on fluid plenum 70C depending on whether a positive or negative purge system is utilized. For clarity, flow passage zone 45 A, 45B, and 45C are all shown on Figure 12B even though their actual positions are as shown above in Figure 6A.

As described previously with respect to the other embodiments of regenerative system 1, fluid ports 18 A, 18B, and 18C enable fluid flow between fluid plenums 70A, 70B, and 70C and regenerative compartments RDl, RD2, RD3, RD4, RD5, and RD6 respectively through flow passage zones 45A, 45B, and 45C on endless belt 40C. Regenerative devices RDl, RD2, RD3, RD4, RD5, and RD6 contain regenerative heat-sink materials 78 of the type described above. At their second ends, regenerative devices RDl, RD2, RD3, RD4, RD5, and RD5 are each in fluid communication with common combustion chamber 140.

Combustion chamber 140 has an energy transfer device 150 which could be any of the heating devices mentioned previously. The purpose of energy transfer device 150 is to initially provide heat-energy to bring the regenerative heat-sink materials 78 in the regenerative compartments , RDl, RD2, RD3, RD4, RD5, and RD6, up to a predetermined operating temperature prior to the introduction of NOC containing fluid A into regenerative system 1.

Assume, for example, that endless belt 40C is positioned so that flow passage zones 45 A overlap fluid inlets 18A of regenerative compartments RDl and RD2 , flow passage zones 45B overlap fluid inlets 18B of regenerative compartments RD4 and RD5 , and flow passage zones 45C overlap fluid flow ports 18C of regenerative compartments RD3 and RD6. Thus process fluid A passes through fluid inlet 90A into fluid plenum 70A, then passes through flow passage zone 45 A, fluid inlet 18A of regenerative compartments RDl and RD2 into regenerative compartments RDl and RD2. Regenerative material 78 in regenerative compartments RDl and RD2 has been heated in the start-up operation as described above or in a previous operating cycle. Since process fluid A is cooler than regenerative material 78, it removes heat from regenerative material 78 while itself getting heated. Regenerative material 78 in regenerative compartments RDl and RD2 therefore get cooled while process fluid A gets heated to a higher temperature which is termed a preheat temperature. The preheated fluid A now enters combustion chamber 140 where it is further elevated in temperature either through spontaneous thermal oxidation of the NOCs contained in it, or by accepting energy provided by energy transfer device 150 or by a combination of the two. The cleaned hot process fluid, now designated as process fluid B, leaves combustion chamber 140 and enters regenerative compartments RD4 and RD5. The regenerative heat-sink material 78 in regenerative compartments RD4 and RD5 was previously contacted by cold process fluid A in a previous cycle and is therefore at a relatively lower temperature than hot process fluid B. Process fluid B therefore gives up its heat to the regenerative heat-sink material 78 in regenerative compartments RD4 and RD5. The regenerative heat-sink material 78 in regenerative compartments RD4 and RD5 therefore gets heated while process fluid B gets cooled. The cooled process fluid B then exits regenerative compartments RD4 and RD5 through fluid outlets 18B, then enters fluid plenum 70B through flow passage zones 45B on endless belt 40C, and finally exits regenerative system 1 through process fluid outlet 90B.

As described above with respect to the regenerative system 1 in Figure 9, purge fluid C is used to remove residual NOC containing fluid (process fluid A) from any of regenerative devices RDl to RD6 prior to its receiving the cleaned process fluid (process fluid B). As described previously, purge fluid C can be an external clean fluid such as ambient air. Alternately, it can be a portion of the cleaned process fluid (process fluid B) which is recycled from fluid plenum 90B or the exhaust stack (not shown) of regenerative system 1. In such a situation, the purge fluid C is introduced under positive pressure by means of a fan or blower (not shown), if necessary, into fluid plenum 70C through fluid inlet 90C. Purge fluid C then enters the two regenerative compartments , which are currently being purged. In the above example, regenerative compartment RD3 and RD6 are being purged. Therefore, purge fluid C flows through flow passage zones 45C into fluid ports 18C in regenerative devices RD3 and RD6 into regenerative compartments RD3 and RD6 and pushes the residual process fluid A into combustion chamber 140 where the NOCs are oxidized.

Alternately, a source of negative pressure such as an induced-draft fan (not shown) can be connected to fluid outlet 90C on fluid plenum 70C. The induced draft fan pulls the residual process fluid A from regenerative compartments RD3 and RD6. In this case, the residual process fluid A that is pulled from the regenerative compartment is designated as purge fluid C. Purge fluid C flows from regenerative compartments RD3 and RD6 through fluid ports 18C and through flow passage zones 45C into fluid plenum 70C and then through process fluid outlet 90C into the induced-draft purge fan. The purge fan then recycles purge fluid C back into the process fluid inlet duct where it mixes with and becomes a part of fluid A.

As will be apparent from previous descriptions of other embodiments of regenerative system 1, as flow control means 40C is moved, each of the regenerative devices RDl to RD6 experiences two contact periods with fluid A, one contact period with purge fluid C, two contact periods with fluid B, and one contact period with purge fluid C.

It is not necessary that a purge fluid C be used with regenerative system 1 of Figures 12A and 12B. If the NOC Destruction and Removal Efficiency (DRE) requirements are not stringent, then a regenerative system without a purge can be used. As an example, a regenerative system which uses six regenerative compartments in which three regenerative compartments are cooled by dirty process fluid A and three regenerative compartments are being heated by oxidized fluid B could be used with not purging of any of the regenerative compartments. Similarly, it is not necessary that two regenerative compartments be purged at a time as shown in the first example. If the NOC DRE requirements are not stringent, then a system in which only one regenerative compartment is purged at a time can be used. For example, a regenerative thermal oxidizer in which two regenerative compartments are being cooled by dirty process fluid A and two regenerative compartments are being heated by oxidized fluid B, one regenerative compartments ^' is being purged by purge fluid C, while another regenerative compartments is idle could be used. Thus the purge system only purges the regenerative compartments which previously received dirty process fluid A and does not purge the regenerative compartments which previously received the clean oxidized process fluid B. Also it is not necessary that an equal number of beds contact fluids A and B respectively. For example, the Regenerative Thermal Oxidizer described above could have three compartments contacting fluid A, two compartments contacting fluid B, and one compartment being purged. Many other combinations of flow arrangements of the process fluids through the regenerative compartments are possible and will be apparent to a person having ordinary skill in the art. Further, any number of compartments can be used. For example, a Regenerative Thermal Oxidizer system can have 12 compartments could be used. In this example, five regenerative compartments could be heated and five regenerative compartments could be cooled while the remaining two intermediate regenerative compartments could be purged. Yet other combinations of the number of beds, the allocation of fluids to beds, and purge systems are possible.

The regenerative oxidizer system described above with respect to Figures 12A and 12B can be easily adapted for catalytic oxidation by incorporating catalyst 130 about the upper section 78U of regenerative heat-sink material 78. An embodiment of regenerative system 1, which incorporates a catalyst 130 for oxidation of the NOCs at a lower auto- ignition temperature is shown in Figure 13. As described previously with respect to the embodiment of the regenerative system 1 of Figure 10, catalyst 130 can be coated on heat sink regenerative material 78 or could be mixed with the heat-sink regenerative material 78 or could be arranged in a single layer or multiple layers within or on top of the heat-sink regenerative material 78. Catalyst 130 is located so that it is initially heated to its operating temperature, either directly or indirectly by energy input device 150. The use of catalysts for oxidizing NOCs is well known. The operation of the catalytic regenerative oxidizer follows the operational steps described above for the Regenerative Thermal Oxidizer system of Figure 12A and 12B.

Yet other embodiments of the regenerative systems described above are possible. For example, it is not necessary that two belts be used with the regenerative systems of Figures 7A, 7B, 8, 9, 10, and 11. A endless belt 40" which services both sets of plenums, 70A, 70B, 70C and 70 A', 70B', 70C respectively can be used as shown in Figure 14A. The operation of the regenerative system 1 of Figure 14 follows the operational steps of the embodiment of regenerative system 1 of Figures. 7A, 7B, 8, 9, 10, and 11. Yet another embodiment of regenerative system 1 according to Figure 7A which incorporates a single drive mechanism 50B" to move both endless belts 40C and 40C is shown in Figure 14B. The endless belts means 40C and 40C are designed to be substantially identical in length and geometry. As shown in Figure 14B, endless belts 40C and 40C are positioned so that they sandwich regenerative compartments RDl through RD6 so that a regenerative compartment which is contacting fluid A has a fluid passage zone 45 A at its first end and a fluid passage zone 45 A' at its second end. Similarly, a regenerative compartment, which is contacting fluid B has a fluid passage zone 45B at its first end and a fluid passage zone 45B' at its second end. The operation of regenerative system 1 of Figure 14B follows the operational steps described above for the regenerative systems of Figure 7A, 7B, 8, 9, 10, and 11.

The endless belts used in any of the embodiments of the regenerative systems described above can be externally cleaned during operation of the system. Because the endless belt 40C generally moves very slowly in most regenerative systems , cleaning can be manual or mechanical or thermal. Various embodiments of regenerative system 1 which use mechanical and thermal cleaning systems such as high pressure jets, stationary brushes, rotating brushes, bake-out chambers etc. to clean the endless belt embodiment 40C, are shown in Figures. 15, 16A, 16B, and 16C.

Figure 15 shows the regenerative system 1 of Figures 12A and 12B, wherein endless belt 40C passes through a clean-out chamber 180 wherein pyrolizable matter that may have deposited on endless belt 40C is pyrolized using a heating device 182. The pyrolized matter is captured and returned back to the combustion chamber 140 of regenerative system 1 using a recycle fan 184 and recycle duct loop 186. While heating device 182 is represented as electric heating elements in Fig. 15, any other heating device can be used to heat endless belt 40C above the pyrolization temperature of the deposited matter. For example, heating device 182 can be any of the other heating devices described earlier in this description.

Another example of a cleaning system to remove dirt from endless belt 40C is shown in the detail representation of Figure 16A wherein high pressure compressed air or water or chemical cleaning solution or some other suitable cleaning medium such as sand 188 is blasted against the upper surface 84 and the lower surface 86 of endless belt 40C to physically dislodge deposited matter from surfaces 84 and 86 of the endless belt. A third example of a cleaning system is shown in the detail representation of Figure 16B wherein stationary cleaning brushes 190 are shown contacted against the upper and lower surfaces of endless belt 40C to physically dislodge deposited matter from surfaces 84 and 86 of endless belt 40C.

A fourth example of a cleaning system is shown in the detail representation of Figure 16C wherein rotating cleaning brushes 192 are shown contacted against the upper and lower surfaces of endless belt 40C to physically dislodge deposited matter from surfaces 84 and 86 of endless belt 40C.

The above cleaning methods may also be used in conjunction with each other. For example, pyrolysis or thermal bake-out and mechanical cleaning and high-pressure blast cleaning can all be used in a regenerative system to clean the endless belt. All of the cleaning methods described are representations of the various cleaning methods that can be used to clean the surfaces of endless belt 40C. Other cleaning methods can equally well be used.

While the endless belt cleaning method is shown for cleaning the endless belt outside the fluid plenum, the cleaning method can also be used within the fluid plenum. For example, doctor blades or brushes can be provided within the fluid plenum for dislodging the deposited particulate matter into the fluid plenum. A movable scrapper or a screw conveyor can then be used to remove the accumulated dislodged particulate matter from the fluid plenum out of the regenerative system. The ends of the regenerative devices need not be horizontally oriented as shown in the above descriptions. The ends could be inclined or vertical without exceeding the scope of the invention. The ends of the regenerative devices also need not be flat as shown in the above descriptions. They could be curved and still operate within the scope of the invention. Further drive means 50 as well as endless belt 40 could be totally located within the fluid plenums and still operate within the scope of the invention. The endless belt need not be looped around the fluid plenums only. For, example, the endless belt could also be looped around the regenerative heat-exchanger/combustion chamber section of the embodiment of regenerative system 1 shown in Figure 12A and still operate within the scope of the invention.

Yet further it is not necessary that an endless belt be used to in the above described regenerative systems. For example open-ended belts with flow passages zones as described above and shown in Figure 18 could also be used. The belts could alternately be advanced in a first and a opposite second direction to selectively align its flow passage zones with the flow ports on the fluid plenums and the regenerative compartments to enable the process fluids to selectively flow through the regenerative compartments as described above. The ends of the belts could be spooled or dropped into take-up wells at either end of the regenerative system. In this case, the drive 150 would first revolve in a first direction and then revolve in a second opposite direction to reverse the direction of movement of the belt.

Multiple units of the regenerative system of Figure 7 can be conveniently stacked on top of one another to enable the use of a common inlet plenum 70A and endless belt 40C with regenerative systems 1 and 1'. This arrangement is shown in Figure 17 wherein inlet plenum 70A and endless belt 40C are sandwiched between regenerative compartments RD 1 to RD6 and RDl' to RD6¹ of regenerative systems 1 and 1' respectively. Drives 50B' and 50B" revolve in the same direction and opposite to the direction of drive 50B to enable the flow zones on endless belts 40C, 40C, and 40C" to align to provide the required regenerative operation. Thus, the fluids contact the regenerative materials in regenerative compartments RDl to RD6 in regenerative system 1 from the right to the left i.e. from regenerative compartments RD6 to RD5 to RD4 to RD3 to RD2 to RDl . In regenerative system 1', the fluids contact the regenerative materials in regenerative compartments RDl' to RD6' from the left to the right i.e. from regenerative compartments RDl' to RD2' to RD3' to RD4' to RD5¹ to RD6'. Such a stacked arrangement is particularly useful where a large quantity of fluid needs to be processed.

Claims

CLAIMS:

1. A regenerative apparatus for processing fluids comprising: a first chamber having an inlet port and an outlet port; a second chamber having an inlet port and an outlet port; a first regenerative compartment including a regenerative material, the first regenerative compartment having an inlet port in communication with outlet port of the first chamber and an outlet port in communication with the inlet port of the second chamber; a second regenerative compartment including a regenerative material, the second regenerative compartment having an inlet port in communication with the outlet port of the first chamber and an outlet port in communication with the inlet port of the second chamber, a valve in the form of a movable belt between the chambers and the compartments, the belt comprising a solid zone and a plurality of flow through apertures positioned thereon such that movement of the belt successively opens fluid communication pathways in a predetermined configuration between selected ports of the first and second chambers on the one hand and selected ports of the first and second regenerative compartments on the other hand when a flow through aperture is located therebetween, and closes the fluid communication pathways when a solid zone is located therebetween.

2. The regenerative apparatus for processing fluids of claim 1, wherein at least one flow through aperture on the belt is sized to partially overlap the inlet or outlet ports of the first and second regenerative compartments when the belt is in an intermediate position between the opening and closing of the fluid communication pathways for uninterrupted flow to or from the regenerative compartment.

3. The regenerative apparatus for processing fluids of claim 1 , wherein the belt comprises at least two flexible belts, and at least one flow through aperture is located on each of the flexible belts.

4. The regenerative apparatus for processing fluids of claim 1, wherein the belt is an endless belt.

5. The regenerative apparatus for processing fluids of claim 1, wherein the belt is a metallic belt.

6. The regenerative apparatus for processing fluids of claim 1, comprising at least two fluid flow pathways, one in each of the first and second regenerative compartments respectively, and the direction of flow in the first fluid pathway in the first regenerative compartment is substantially counter-current to the direction of flow in the second fluid pathway in the second regenerative compartment.

7. The regenerative apparatus for processing fluids of claim 1, wherein the regenerative material is a heat-sink material.

8. The regenerative apparatus for processing fluids of claim 7, wherein the heat- sink material comprises a catalyst.

9. The regenerative apparatus for processing fluids of claim 1, wherein the regenerative material is an adsorption material.

10. The regenerative apparatus for processing fluids of claim 1, wherein the regenerative material is a chemically reactive material which has a first chemical state when in contact with a first fluid, assumes a second chemical state when in contact with a second fluid and reverts back to the first chemical state when in contact again with the first fluid.

11. The regenerative apparatus for processing fluids of claim 1, further including means for on-line cleaning of the belt.

12. The regenerative apparatus for processing fluids of claim 1, further comprising a means to control the temperature of the regenerative material by adding external energy to the regenerative material or removing excess energy from the regenerative material.

13. The regenerative apparatus for processing fluids of claim 1, comprising at least one additional chamber having an inlet port and an outlet port, the belt having flow through apertures positioned for selectively opening a fluid commumcation pathway between the additional chamber and at least one of the first and second regenerative compartments, the fluid communication pathway being closed by a solid zone of the belt upon further movement of the belt.

14. The regenerative apparatus for processing fluids of claim 1, further comprising at least one additional regenerative compartment having an inlet port and an outlet port, and at least one additional flow through aperture in the belt which selectively opens a fluid communication pathway in a predetermined configuration between selected ports of the first and second chambers on the one hand and the inlet and outlet port of the additional regenerative compartment on the other hand when an additional flow through aperture is located therebetween, and closes the fluid communication pathway when a solid zone of the belt is located therebetween.

15. The regenerative apparatus for processing fluids of claim 14 wherein four additional regenerative compartments are provided.

16. The regenerative apparatus for processing fluids of claim 15 comprising three chambers each receiving a process fluid through the inlet port thereof and six regenerative compartments each having a selected regenerative material for treatment of the process fluid, the belt having a plurality of flow through apertures therein positioned for opening and closing fluid communication pathways between the chambers and the regenerative compartments sequentially and in relation to each other to effect efficient processing of the process fluid.

17. The regenerative apparatus for processing fluids of claim 1 wherein the outlet port of the first chamber comprises a plurality of holes

18. The regenerative apparatus for processing fluids of claim 1 wherein the inlet port of the second chamber comprises a plurality of holes.

19. The regenerative apparatus for processing fluids of claim 1 wherein the belt comprises an elongate flexible member having opposing ends each attached to a spool such that elongate flexible member can be moved from one spool to another, the movement causing the flow through apertures on the belt to open and close fluid communication pathways.

20. The regenerative apparatus for processing fluids of claim 1 wherein at least one regenerative compartment has two inlet ports, and the belt opens and closes a fluid communication pathway for the two inlet ports.

21. The regenerative apparatus for processing fluids of claim 20 wherein two belts are provided, one for each of the two inlet ports, the regenerative apparatus comprising regenerative heat exchanger.

22. The regenerative apparatus for processing fluids of claim 1 further comprising a combustion chamber in fluid communication with at least one of the regenerative compartments, the regenerative apparatus and combustion chamber forming a regenerative thermal oxidizer.

23. The regenerative apparatus for processing fluids of claim 1 wherein each aperture comprises a plurality of holes.

24. The regenerative apparatus for processing fluids of claim 1 comprising at least two stacked sets of regenerative compartments and chamber sharing a common belt.

25. A valve for controlling fluid communication pathways in a regenerative device, the valve comprising: a flexible belt movable along its major axis between a first and a second position and having at least one flow through aperture therein; a fluid plenum having at least two flow passage openings, the flow passage openings located along the length of the belt, the flow passage openings further located adjacent to a first surface of the belt, the first flow passage opening further aligned with the flow through aperture of the belt when the belt is in the first position, the second flow passage opening further aligned with the flow through aperture of the belt when the belt is in the second position, wherein the flow passage openings are sized to allow flow from the fluid plenum to the flow through aperture on the belt; at least two housings; each of the housings having a flow passage opening, each flow passage opening of the housing located adjacent to a second surface of the belt, each flow passage opening being aligned with a flow passage opening on the fluid plenum, each flow passage opening on the housing being sized to allow flow through the flow through aperture on the belt to the housing; and means to move the belt to a first position to permit fluid communication between the fluid plenum and the first housing and to a second position to permit fluid communication between the fluid plenum and the second housing.