All-ceramic heat exchangers, systems in which they are used and processes for the use of such systems

Landfill gas combustion and landfill leachate evaporation systems and the use of forest products or some such fuel to fire a gasifier that will eventually provide energy. Novel all-ceramic heat exchangers, systems in which they are used, and processes that can be handled by such systems.

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Description

This application claims priority from U.S. Provisional Patent Application No. 60/860,105 filed Nov. 20, 2006.

One embodiment of the invention disclosed and claimed herein deals with disposal of landfill gases and leachate. Specifically, the invention is directed to landfill gas combustion and landfill leachate evaporation systems and to the use of forest products or some such fuel to fire a gasifier that will eventually provide energy. More specifically, the invention deals with novel all-ceramic heat exchangers, systems in which they are used, and processes that can be handled by such systems.

BACKGROUND OF THE INVENTION

Landfill leachate is a liquid that has passed through or emerged from solid waste and contains soluble, suspended, or miniscule materials removed from such wastes. Methane gas, produced in vast quantities by landfills, is a large contributor to the greenhouse gases in the atmosphere. Management of leachate and gases resulting from municipal solid waste landfills is an ongoing challenge. All new or laterally expanded municipal solid waste landfills are required to have liners and leachate-collection systems. Landfills have slowly been brought under the regulatory blanket, wherein the noxious leachate must be collected and treated and the odoriferous methane-laden landfill gas must be collected and burned. To meet the newer environmental codes, leachate is transported to water treatment plants for further processing or the leachate is evaporated by combustion of landfill gases in fired evaporators. Surplus landfill gases are burned in specially constructed flare stacks.

Waste to energy systems have been in operation for many years in which pollutants are recovered and destroyed in an attempt to meet environmental codes. Such processes have been used to reclaim precious metals, destroy medical waste, clean acid-laden gases and process sludge, biomass and municipal solid wastes, among many other uses. The applicant is aware of only one piece of prior art, namely, U.S. Pat. No. 4,838,184, by Young, et al, in which a method and apparatus for disposing of noxious landfill-produced leachate and gases is disclosed.

The method disclosed by Young et al basically comprises the steps of combusting at least a portion of the landfill produced gases with air in a first combustion zone to produce a stream of hot combustion products, contacting the landfill produced leachate with the stream of hot combustion products to thereby vaporize a portion of the leachate and form a concentrated leachate residue and a composite gas stream, withdrawing the concentrated leachate residue, and then combusting the composite gas stream with additional air in a second combustion zone to convert noxious components remaining therein, to non-polluting compounds.

Thus, the process of the referenced patent uses hot combustion products to treat the leachate, and the process differs markedly from the instant invention wherein the present invention utilizes hot air to treat and vaporize the leachate before delivery to the burner. There are several other differences between the referenced process and its apparatus and the process and apparatus of the instant invention that will become apparent from the following disclosure describing the processes, systems, and the all-ceramic heat exchangers of the instant invention.

An effort to provide a more beneficial and expedient process for handling both landfill leachate and landfill gases led to the present invention.

SUMMARY OF THE INVENTION

Generally, in one embodiment, the invention comprises a novel all-ceramic indirect air-to-air heat exchanger in combination with other components to form a system. The other components include a burner, staged oxidizer, and a leachate evaporator. The system combusts the methane-rich landfill gas, utilizing air that has been indirectly heated by the all-ceramic indirect air-to-air heat exchanger. The ceramic construction of the heat exchanger of this invention permits heat transfer at higher initial temperatures than conventional metal heat exchangers can withstand, resulting in higher thermal efficiency for the system.

Ambient air is preheated on the air side of the all-ceramic indirect heat exchanger. The preheated air stream is split, with portions being sent to the landfill gas burner and the balance going to a leachate evaporator. The leachate mass contains noncombustibles, unburned volatiles, inert landfill gases and excess air along with the combustion products. By using only hot air as the medium to vaporize the leachate, the ratio of volatiles to combustion air is higher than when one uses hot organic combustibles as the vaporization medium. The hot air mixes with the volatile hydrocarbons and vaporizes the water that is present. The leachate vapor and warm air are sent to a staged oxidizer to directly raise the temperature sufficiently to destroy the hydrocarbons. Preheating of air for landfill gas combustion and leachate evaporation ensures, even as the methane percentage in the landfill gas decreases, that the disposal system will continue to operate without the need for auxiliary fuel.

The instant invention also comprises two embodiments in which the system, with some slight modification, can be used to generate electrical power without the need for a steam boiler and all of the related water treatment, cooling towers, pumps, and the like that are associated with typical steam power plants. In a first embodiment, the system combusts the landfill gas and indirectly heats the air in a high pressure, high temperature, hybrid ceramic heat exchanger. The clean air is sent to an air turbine generator set for production of electrical power. The hot air turbine exhaust is then forwarded to the leachate evaporator. The leachate is vaporized with air rather than products of combustion. In a second embodiment, the system combusts the landfill gas and indirectly heats the air in a high pressure, high temperature, hybrid ceramic heat exchanger. The clean air is sent to an external combustion engine for production of electrical power. The hot air external combustion engine exhaust is then forwarded to the leachate evaporator. The leachate is vaporized with air rather than products of combustion. The utilization of exhaust from a turbine or external combustion engine to evaporate leachate, combined with the air turbine driving with high temperature, high pressure air makes the process considerably more efficient than conventional steam plants.

More specifically, this invention deals with a all ceramic air-to-air indirect heat exchanger that comprises in combination, a metal jacketing and support frame. The support frame has a near end and a distal end. A lower fixed tube sheet is mounted in the near end of the metal support frame for supporting multiple ceramic heat exchanger tubes fitted into openings in the lower tube sheet.

There is a moveable distal end tube sheet mounted in the distal end of the metal support frame such that the ceramic heat exchanger tubes of the heat exchanger are fitted into respective openings in the moveable distal end tube sheet. The moveable distal end tube sheet has an outside edge surface and there is a ceramic gasket mounted on that outside edge surface.

Innovative sealing means are described that minimize air flow between the ceramic tubes and the lower tube sheet, the ceramic tubes and the upper tube sheet, and between the tube sheet and the metal jacketing. Specifically, a novel sealing assembly includes a ceramic spring to provide adjustability during assembly and allows compensation for tube expansion at high temperatures.

A means for entry of air or gas into the air-side of the ceramic heat exchanger is provided, as well as a means for exit of air or gas out of the air side of the ceramic heat exchanger. Likewise, a means for entry and exit of air or gas is provided for the tube-side of the ceramic heat exchanger. Although not required, it is a preferred embodiment of this invention that there be present at least one air baffle mounted in the interior of the heat exchanger to help deflect the air-side fluid into the preferred movement direction.

Another feature of this invention is the system configuration for handling landfill-produced products. The system comprises in combination a housing and support frame having a distal end, a near end and a middle section. In the preferred embodiment, the system is oriented such that the distal end and middle section generally overlie, and are in general alignment with, the near end. However, it is well within the scope of this invention to orient the system so that the system is not vertically aligned. It should be understood by those skilled in the art that even though the system is depicted in the drawings as a vertical assemblage, the system can also be assembled in alternative orientations such as, but not limited to, a horizontal mode.

There is supported in the near end of the support frame, a gas burner assembly, having a distal end, near end, and a middle zone.

Supported in the middle section of the support frame, and mounted on the distal end of the gas burner assembly, is a staged oxidizer unit having a near end section, a distal end section, and a middle section. The distal end section of the staged oxidizer unit has a distal end and there is an air manifold assembly mounted in the distal end section. The near end section and middle sections of the staged oxidizer are fitted with a multiplicity of air conveyance ceramic tuyeres and there is a means for conveying and controlling air to the staged oxidizer through the tuyeres and the air manifold assembly.

There is mounted on the distal end of the staged oxidizer unit an all-ceramic heat exchanger and mounted on the all-ceramic heat exchanger, is a stack for conveying products of combustion from the burner, staged oxidizer and all-ceramic heat exchanger, to the atmosphere.

There is in addition, an evaporator for heating and evaporating liquid materials, the evaporator being heated by percolating high temperature air through liquid materials contained in it.

There is a means for conveying air to the all-ceramic heat exchanger, a means for conveying heated air from the all-ceramic heat exchanger to the evaporator, means for conveying volatile products from the evaporator to the burner and the staged oxidizer, means for supplying liquid materials to the evaporator, and, means for controlling the entire system.

An additional embodiment of this invention is a process for handling landfill-produced products. The process comprises providing a conventional burner that will burn landfill-produced gases, wherein the burner has a distal end and a near end. Landfill produced gases are fed to the burner along with controlled amounts of preheated combustion air to provide a zone temperature in the burner of not more than about 2200° F.

The products of combustion generated within the burner are moved to a staged oxidizer which has a near end, wherein the products of combustion are mixed with heated vapors from an evaporator capable of heating and evaporating liquid landfill-produced products, such that the zone temperature in the near end of the staged oxidizer is in the range of about 1600° F. to about 2200° F. Air is introduced to the staged oxidizer essentially throughout the length of the staged oxidizer wherein the air is mixed with the combustibles and products of combustion as the products move through the staged oxidizer.

As the mixture exits the staged oxidizer it is moved into a multiplicity of ceramic tubes in an all-ceramic heat exchanger, and then through the heat exchanger tubes to exit through the stack to the atmosphere. Meanwhile, landfill produced liquid material is supplied to the evaporator.

There is provided a controlled amount of air into the interior of the all-ceramic heat exchanger to move in and around the ceramic tubes of the all-ceramic heat exchanger to heat the air to a temperature of about 1200° F. to about 2100° F., which air is allowed to exit from the all-ceramic heat exchanger and be conveyed to the evaporator and allowed to percolate into any liquid material present in the evaporator.

The evaporate is collected and conveyed from the evaporator to the burner which may provide a portion of the fuel for the burner, and while moving the evaporate to the burner, a small portion of the evaporate is separated and conveyed to the near end of the staged oxidizer to mix with the oxidizing air therein.

With regard to the turbine aspect of this invention, the system is essentially the same with the following differences.

There is mounted on the all ceramic heat exchanger, a second heat exchanger which can be a metal heat exchanger, or an all-ceramic heat exchanger, the second heat exchanger receiving high temperature heated air from the all-ceramic heat exchanger and supplying medium high temperature heated air to the all-ceramic heat exchanger. It should be understood by those skilled in the art that more than two heat exchangers can be used, and that the additional heat exchangers can be either all-ceramic or metal heat exchangers.

In addition, there is a turbine, the is turbine driven by the use of high temperature heated air from the all-ceramic heat exchanger, and there is a means for conveying high temperature heated air from the all-ceramic heat exchanger to the turbine.

There is a compressor, the compressor being driven by the turbine and the compressor supplying low temperature heated air to the metal heat exchanger. The compressor, for purposes of this invention could be separately driven, and need not essentially be driven from the turbine.

There is a means of supplying ambient air to the compressor, a means of conveying medium high temperature heated air from the turbine to the evaporator, a means for conveying air from the compressor to the second heat exchanger, a means for conveying medium temperature heated air from the metal heat exchanger to the all-ceramic heat exchanger, and a means of mixing medium temperature heated air from the metal heat exchanger, and ambient air, and conveying that air mixture to the staged oxidizer.

Still further, there is a process for handling landfill-produced products that also includes a turbine, in which the process is essentially the same as that mentioned above, but with the following differences.

The mixture from the staged oxidizer is allowed to exit into a multiplicity of ceramic tubes in an all-ceramic heat exchanger, and then through the all-ceramic heat exchanger tubes to a second heat exchanger and then exit through a stack to the atmosphere.

The heated air is allowed to exit from the all-ceramic heat exchanger and is conveyed to a turbine, and then, conveyed from the turbine to an evaporator and then percolated into any liquid material present in the evaporator.

Finally, another embodiment of this invention is the use of a novel sealing system to reduce or eliminate leakage in and around the tube sheet.

Contemplated within the scope of this invention is a system that is capable of complying with the demands of a particular end use. For example, the heat exchangers of this invention in a vertical configuration can be equipped with a floating tube sheet that by virtue of the weight of the dome and the upper tube sheet will maintain its own seal.

For medium pressures, that is up to about 15 psig, the heat exchangers of this invention in a vertical configuration can be equipped with a dome having mechanical assistance to hold the seal, such as adjustable bolts or springs, the details of which can be found infra.

For pressures above 15 psig, the heat exchanger is considered by code to be an ASME pressure vessel. When using preheated air to drive a turbine, the exchanger air side will be at pressures of 15 psig or more and expansion not only has to be controlled, but the interior ceramic heat tubes will no longer act as columns to help support the tube sheet and the dome. Thus, what is contemplated and claimed herein is the use of mechanical controls, specifically, hydraulic controllers. During start up, the hydraulic pressure of the hydraulic controllers is set at a level that would maintain tube-to-tube-to-sheet sealing. As pressure increases on the air side, there is a tendency to push the tubes apart. The hydraulic controls maintain the pressure differential at the tube-to-tube-sheet joint as the air side pressure increases.

It is also contemplated within the scope of this invention to use pneumatic controllers as the mechanical controls used to control the tube-to-tube-sheet sealing in the high pressure applications, the details of which are set forth infra.

In an alternative embodiment, the system described herein may also employ an external combustion engine as means to use recovered heat energy to produce power. By inclusion of a heat engine or external combustion engine the energy recovered by the heat exchanger can be used for power generation for use in other processes. Furthermore, because the external combustion engine requires high temperature input, that is, approximately 1800 degrees F., and discharges a moderate temperature flue gas, that is, approximately 1500 degrees F., the output from the external combustion engine can be sent to an additional heat exchanger for additional heat energy recovery.

External combustion engines are well suited for used in the inventive system because they are known to be very reliable, are available at relatively low cost, and require high temperature energy flue gas of low particulate level as an input energy source. External combustion engines operate at atmospheric pressures, and thus the heat recovery system, specifically the vertical all-ceramic heat exchanger described herein, does not require modification to accommodate high pressures associated with turbine systems.

Another embodiment of this invention is a power plant that can be fired with biomass, poultry litter, and the like.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an overall side view of one system of this invention.

FIG. 2 is a full side sectional view across line A-A of FIG. 1, showing the internal configuration of the stacked components.

FIG. 3 is a side sectional view across line A-A of FIG. 1 of the burner with an air manifold mounted on the top.

FIG. 4 is a side sectional view across line A-A of FIG. 1 of the staged oxidizer with an air manifold mounted on the top.

FIG. 5 is a side sectional view across line A-A of FIG. 1 of the all-ceramic indirect air-to-air heat exchanger illustrating the baffles used to direct air flow within the air side of the apparatus.

FIG. 6 is a detailed sectional view of the upper tube sheet within the all-ceramic indirect air-to-air heat exchanger illustrating the upper sealing assembly between the ceramic tube and upper tube sheet, as well as the gasketing between the tube sheet and the heat exchanger shell.

FIG. 7 is a detailed sectional view of the lower tube sheet within the all ceramic indirect air-to-air heat exchanger illustrating the lower sealing assembly between the ceramic tube and the lower tube sheet.

FIG. 8 is a detailed sectional view of the upper tube sheet within the all ceramic indirect air-to-air heat exchanger illustrating the upper sealing assembly between the ceramic tube and the upper tube sheet.

FIG. 9 is a full side view of a heat exchanger with the spring-loaded device for maintaining the seal of the dome to the heat exchanger.

FIG. 10 is an enlarged view of the detail of the spring loaded device of FIG. 9.

FIG. 11 is side sectional view of the evaporator unit with the side panel removed.

FIG. 12 is an end sectional view of the evaporator unit illustrating the heating tubes within the reservoir.

FIG. 13 is an overall view of a second embodiment of the system of this invention which incorporates a turbine generator that can be used for production of electrical power.

FIG. 14 is a schematic diagram of the fluid flow through the preferred embodiment of the invention.

FIG. 15 is a schematic diagram of the fluid flow through a second embodiment of the invention wherein heat energy is used to generate power using a turbine system.

FIG. 16 is a schematic diagram of the fluid flow through the preferred embodiment of the invention wherein heat energy is used to generate power.

 DETAILED DESCRIPTION OF THE DRAWINGS

Turning now to FIG. 1, there is shown a full side view of a system of this invention in a vertical configuration. It is to be noted that with slight modification of the all-ceramic indirect air-to-air heat exchanger, the system can also be operated in a horizontal position to give similar effects. Such modification is described below. With regard to FIG. 1, there is shown the preferred stacked arrangement of the components of this invention in which there is shown a burner 1, an air manifold 2 mounted on the burner stack 3, a staged oxidizer 4 mounted on the air manifold 2, a second air manifold 5 mounted on the staged oxidizer 4, an all-ceramic heat exchanger 6 mounted on the air manifold 5, and a stack assembly 7 mounted on the heat exchanger 6.

In addition, FIG. 1 shows an evaporator 8, a general control panel 9 for controlling the entire system, and a solids recovery assembly 10, along with the various significant conveying means for the system, namely, the leachate delivery line 11, the evaporate conveyance line 12, the hot air conveyance line 13, the ambient air conveyance line 14, and the fuel delivery line 15, and the support frame 16 for the stack, the intimate details of each being described infra.

Turning now to FIG. 2, which is a cross section of the stacked components of FIG. 1, through the lines A-A, and with regard to each of the FIGS. 3, 4, and 5, which are respectively cross-sectional views taken directly from FIG. 2 and enlarged to make clearer the detail therein, there is shown the burner unit 1, the air manifold 2, the staged oxidizer 4, the air manifold 5, the all-ceramic heat exchanger 6 and the exhaust stack assembly 7.

Focusing on FIG. 3, but with regard to the arrangement in FIG. 2, there can be observed that the burner 1 is a conventional landfill leachate gas burner. The conventional landfill gas burner consists, in this case, of a sealed burner, burner management system, controls, propane pilot and a booster fan, that injects the gas into the housing and maintains a flame regardless of the percentage of methane in the landfill gas. Since these components are conventional in the art, it is not deemed necessary to provide details of their operation. For purposes of this invention, the burner has been modified to provide an open space 21 between the wall 23 and the firebrick. This open space 21 is used to convey vaporous leachate to the air manifold 2. In standard operation with this type of burner, if the percentage of methane in the gas flow drops below the amount needed to maintain a useful flame, an auxiliary fuel will automatically inject. Typically, #2 fuel oil is the preferred auxiliary fuel. As shown in FIG. 3, the burner is additionally comprised of a fuel feed line 15, which delivers fuel to the burner 1. The fuel is propelled through the burner 1 to the burner pot 17 and is mixed with vaporous leachate 18 flowing through line 12 from the evaporator 8, which is shown in FIG. 1, which arrives at the pot 17 via a delivery line 12 and through a delivery port 19 (FIG. 2), directly from the evaporator unit 8. The vaporous leachate 18 at this point also contains air and has a temperature in the range of from about 300° F. to about 500° F. The temperature of leachate 18 is a result of heating of the liquid leachate 25 within evaporator unit 8.

Leading from the chamber 20 and surrounding the burner pot 17, it will be noted that there is a open space 21, which surrounds the fire brick 22 of the burner stack 3 and is contained by the outside wall 23 of the burner 1. This outside space 21, it will be further noted, leads to the top 24 of the stack 3, and exits internally into the air manifold 2. The purpose of this open space 21 is allow a small portion 27 of the vaporous leachate 18 to split off from the larger portion of vaporous leachate 18 prior to the vaporous leachate 18 being fed to the burner through conduit 25 to the burner pot 17. The split off portion 27 of the vaporous leachate 18 is fed to the air manifold 2 of the burner 1 and is mixed with ambient combustion air mixed with heated air from the all-ceramic heat exchanger 6 that will be described infra. The benefit of splitting the leachate is that the portion that flows to the air manifold 2 is a tempering gas, that is a small amount of the leachate vapor goes to the burner to burn and control the flame and the flame shape, while a larger portion goes to the air manifold to temper the air flow. The preheated air coming from the all-ceramic heat exchanger 6 has a temperature in the range of about 1200° F. to about 1600° F. Thus, when the flue gas resulting from the combustion of vaporous leachate 18 reaches the air manifold 2, its temperature is in the range of about 1800° F. to about 2200° F. By maintaining the combustion flue gas of the vaporous leachate 18 in this temperature range, the amount of NOx formed is reduced considerably.

With regard to FIG. 4 which is a cross-sectional view of the two-stage oxidizer 4, it can be noted that the products of combustion exit air manifold 2 into the first stage of staged oxidizer 4 where the gases mix with the balance of the tempering air and the by-products of the leachate vapors 18, wherein the temperature drops to somewhere in the range of about 1600° F. to about 1900° F. for the non-turbine apparatus, and will hold at about 2200° F. for the process with the turbine-containing apparatus. The overfire air from the air manifold 2 is used to control and hold the first stage of the oxidizer at a preset temperature.

The first stage is sized to hold the vapor and landfill gas at a temperature between 1600° F. and 2400° F. for a short period of time, on the order of 1 or 2 seconds, depending on the percentage of landfill gas and water vapor. The longer time is required if the water vapor is higher.

The second stage of the staged oxidizer 4 allows the mixture of air and the flue gas products from the first stage to complete combustion and hold the discharge temperature at about 1600° F. when the system has been designed to evaporate leachate and combust landfill gas only. However, when an air turbine is furnished as part of the process to generate power, the tempering air section is reduced in size and will hold the inlet temperature at the heat exchanger at about 2200° F.

Staged oxidizer 4 is a hollow cylindrical body that is completely lined with refractory brick 28. Refractory brick lining 28 is received within and slightly spaced apart from support steel 29, forming a hollow sleeve 33. Ceramic tuyeres 26 are formed within lining 28 such that they extend from hollow sleeve 33 and open on the interior surface of staged oxidizer 4. Tuyeres 26 are evenly and frequently spaced about the entire inner surface and constructed with a slotted front face 30 and a single entrance 31 on the back 32 that permits the entrance of air without direct radiation between the interior of the staged oxidizer 4 and the support steel 29. Preheated air is directed from the all-ceramic heat exchanger 6, is received by the staged oxidizer 4 using the hollow sleeve 33, and directed to the interior via tuyeres 26. The temperature of this preheated air is on the order of about 1400° F.

It should be noted by those skilled in the art that a second air manifold 5 can be installed between the staged oxidizer 4 and the all-ceramic heat exchanger 6 if desired, although, it is not required. Such an insertion is required when there is need for additional heat control over the products moving from the staged oxidizer 4 and the heat exchanger 6. Additional air manifold 5 is shown in place in FIGS. 2 and 4.

The details of similar all-ceramic heat exchangers can be found in U.S. Pat. No. 5,979,543, which issued Nov. 9, 1999 for low to medium pressure and temperature, all-ceramic heat exchangers and U.S. Pat. No. 5,775,414, which issued Jul. 7, 1998, for high temperature, high pressure, all-ceramic heat exchangers, both in the name of the inventor herein. These patents are hereby incorporated by reference for what they teach about the construction of all-ceramic heat exchangers and their uses.

Turning now to FIG. 5 which is a full cross-sectional view from FIG. 2, showing the interior of the all-ceramic heat exchanger 6 of this invention, there is shown a bottom tube sheet 34 which is securely mounted on top of the air manifold 5, if such manifold is used, otherwise, directly on the top of the staged oxidizer 4. The positioning of, and the securing means for the tube sheet 34 is intended to keep the tube sheet 34 essentially immovable with regard to both vertical and lateral significant movement.

Shown in place as when operational, and oriented vertically are a multiplicity of openings or channels 35 through bottom tube sheet 34. Within each channel 35 stands an elongate all-ceramic tube 36. The lower end 37 of each tube 36 is supported within and sealed relative to bottom tube sheet 34 using a lower sealing assembly 120. The upper end 38 of each tube 36 is received within one of multiple openings or channels 40 through top tube sheet 39. An upper sealing assembly 100 resides within each channel 40 and seals and supports upper end 38 of each tube 36 with respect to top tube sheet 39. The hot flue gas from the staged oxidizer 4 is moved through these ceramic tubes 36, and as a consequence, the ceramic tubes 36 are heated and expand, the significance of the result being described infra.

In the preferred embodiment bottom tube sheet 34 and top tube sheet 39 are monolithic cast refractory plates, as described in co-pending application Ser. No. 10/915,824, filed Aug. 11, 2004 and incorporated by reference herein for what it teaches about monolithic cast refractory plates. However, tube sheets of alternate construction can be substituted, including, but not limited to, jack sprung arch tube sheets. Monolithic tube sheets may be rectangular or circular in shape. Tube sheet thickness is determined by the requirements of the specific application wherein higher pressure applications require a greater thickness than those required by lower pressure applications.

Referring to FIG. 7, each channel 35 in bottom tube sheet 34 is provided with a bell-shaped inlet 121 in accordance with ASME Long Radius Nozzle criteria so as to minimize pressure drop. The outlet 125 of each channel 35 is provided with a lower sealing assembly 120 that seals and supports lower end 37 ceramic tube 36 relative to bottom tube sheet 34. Lower sealing assembly 120 includes pan seal seat 122, tube collar 124, and packing 126. Outlet 125 of channel 35 is enlarged to form a cylindrical vacancy 130 in which resides pan seal seat 122. Pan seal seat 122 is generally cup shaped and provides a lining for the interior surfaces of vacancy 130. Tube collar 124 is also generally cup shaped resides within pan seal seat 122 in a nested fashion. Pan seal seat 122 and tube collar 124 are both provided with an axially aligned opening 123 sized and shaped to correspond identically to the interior opening of tube 36. Opening 123 permits fluid flow between channel 35 and the interior of tube 36.

Pan seal seat 122 and tube collar 124 are formed of silicon carbide, and are manufactured and fitted together to ensure a tight seal between the two parts. This is in comparison to casting the seat as part of the tube sheet, which is a more unwieldy and more expensive due to requirements of special tooling. Once manufactured, the inventive assembly 120 is placed in the cast form for the monolithic tube sheet, and the tube sheet is cast around the assembly 120. When the tube sheet is subsequently fired, the seal becomes an integral part of the tube sheet.

When assembled, lower end 37 of ceramic tube 36 is received within the interior of tube collar 124 and the two components are cemented together. The thrust from tube 36, due to thermal expansion and resulting from the weight of the tube 36 and top tube sheet 39, is carried through tube collar 124 and pan seal seat 122 to bottom tube sheet 34.

Packing 126, a dense mineral wool or high temperature caulking, is provided between the lateral confronting surfaces of pan seal seat 122 and tube collar 124. Packing 126 holds the assembly in place and allows for lateral movement and expansion, but is not required for sealing as all sealing is accomplished in the compression between pan seal seat 122 and tube collar 124.

Referring now to FIG. 8, each channel 40 in top tube sheet 39 is provided with upper sealing assembly 100. Upper sealing assembly 100 lines the interior of each channel 40 such that it extends between the inner and outer surfaces of top tube sheet 40, and includes seat 106, venturi pan seal 108, sliding ring seal 110, ceramic spring 112, and plug 102. In the preferred embodiment, seat 106, venturi pan seal 108, sliding ring seal 110, ceramic spring 112 and plug 102 are all formed of silicon carbide, wherein the ceramic spring 112 is manufactured from a siliconized silicon carbide. Manufacturing all the components of sealing assembly 100 from the same material makes it easier to hold closer tolerances and thus provides a tighter seal.

Seat 106 is an elongate sleeve having an overall length corresponding to the thickness of top tube sheet 39. Adjacent each respective inlet 101 and outlet 105 of channel 40, seat 106 is shown having a laterally outwardly extending lip 109 which retains seat 106 within channel 40. Alternative retention means may be substituted for lip 109, including, but not limited to, providing a center tongue extending laterally outwardly from the exterior of seat 106, or providing the exterior surface of seat 106 with a wavy contour. The interior surface of seat 106 is partially threaded such that the threaded portion 104 extends approximately between the mid-thickness of top tube sheet 39 toward outlet 105 of channel 40, terminating adjacent to but spaced apart from outlet 105. Seat threads 104 are sized and shaped to be form a tight fit when received within corresponding plug threads 103 of plug 102. During manufacture, seat 106 is prefired, and then cast in place within top tube sheet 39. This reduces manufacturing costs since the need for expensive threaded tooling is eliminated.

All remaining components of upper sealing assembly 100 reside generally within the interior space of seat 106, and are arranged in a stacked configuration from inlet 101 to outlet 105 such that the upper end 38 of tube 36 is capped by venturi pan seal 108, the upper end of venturi pan seal 108 supports the lower end of sliding ring seal 110, the lowest turn of ceramic spring 112 is supported by sliding ring seal 110, and the lower edge of plug 102 abuts and confronts the highest turn of ceramic spring 112.

Venturi pan seal 108 is a hollow cylindrical tube with an interior diameter which is uniform along its length except at its lower end 113, where the interior diameter tapers outwardly adjacent lower end 113. The exterior diameter of venturi pan seal 108 is non-uniform such that its upper end 111 has an outer diameter which is approximately the same as the outer diameter of tube 36, and its lower end 113 has an outer diameter which is slightly less than the interior diameter of tube 36, resulting in a shoulder 115 between upper end 111 and lower end 113. In use, lower end 113 of venturi pan seal 108 is received within the interior of upper end 38 of tube 36 to the extent that the upper end 38 of tube 36 confronts and abuts shoulder 115. Upper end 111 terminates in an upper surface 114 that is formed having a slightly upwardly convex curvature to accommodate rotations of tube 36.

Sliding ring seal 110 is a hollow cylindrical tube with an interior diameter that is uniform along its length. The exterior diameter of sliding ring seal 110 is non-uniform such that its lower end 117 has an outer diameter which is slightly less than the interior diameter of seat 106 and its upper end 116 has an outer diameter which is less than the outer diameter at its lower end, resulting in a shoulder 118 between upper end 116 and lower end 117. The outer diameter of upper end 116 is slightly less than the inner diameter of ceramic spring 112. In use, upper end 116 is received within the interior of ceramic spring 112 to the extent that the lowest turn of ceramic spring 112 confronts and abuts shoulder 118. Upper end 116 is provided in a length that is slightly shorter than ceramic spring 112 to allow for compression of spring 112. Lower end 117 of sliding ring seal 110 is supported by venturi pan seal 108 and terminates in a lower surface 140 which is formed having a slightly upwardly concave curvature which receives and accommodates upper surface 114 of venturi pan seal 108.

Ceramic spring 112 acts between plug 102 and sliding ring seal 110 and accomplishes several important functions within upper sealing assembly 100. Spring 112 provides adjustability during assembly of tube 36 within top tube sheet 39, allowing for normal variations in tube length. In use, spring 112 maintains a sealing pressure on tube 36 within upper sealing assembly 100, and also allows upper sealing assembly 100 to accommodate all of the longitudinal (horizontal) heat expansion of tube 36. Ceramic spring 112 maintains its elastic properties at temperatures up to 2400 degrees F.

Plug 102 is a hollow cylindrical body and resides about the interior of seat 106 adjacent outlet 105. The interior surface of plug 102 is outwardly tapered 107 at the upper end, and is provided with an open interior which is aligned with and has the same inner diameter as the interior of sliding ring seal 110 and venture pan seal 108. The exterior surface of plug 102 is provided with a threaded portion 103 which extends upward from the lower end, and terminates before the upper end. Plug threads 103 transmit upward thrust from tube 36 to seat threads 104, seat 106 transferring the thrust to top tube sheet 39. For both plug threads 103 and seat threads 104, the number of threads used is determined by the pressures required by the application, where increased pressures require an increase in the number of threads provided.

When operational, and as indicated above, the ceramic tubes 36 expand when heated, the higher the temperature, the more the expansion (within limits) of the ceramic tubes 36, both linearly and laterally, within the heat exchanger 6. Thus, when the ceramic tubes 36 are heated, they will lift the movable top tube sheet 39, increasing the distance between the movable top tube sheet 39 and fixed bottom tube sheet 34. The top tube sheet 39 is designed by calculations to weigh approximately 140 lbs/cu. ft. to about 170 lbs/cu. ft. and if the air pressure differential does not exceed 10 lbs to 15 lbs which means staying within codes and safety measures. The heat exchangers of this invention, in a vertical configuration, can be equipped with a floating tub sheet that by virtue of the weight of the dome and the upper tube sheet will maintain its own seal. Thus, under normal conditions, the top tube sheet 39 will have a tendency to stay pressed against the upper sealing assembly 100 and maintain a seal for the heat exchanger 6.

However, for medium pressure, that is up to about 15 psig, the heat exchangers of this invention can be equipped with a dome having mechanical assistance to hold the seal, such as adjustable bolts or springs. Such a device is shown in FIG. 9, wherein there is shown a horizontal heat exchanger that is equipped with a spring loaded device 131, consisting of a tie down bolt arrangement 132 at the bottom end and the spring loaded canister 133 at the top end. An enlarged detail of the spring canister 133 can be found in FIG. 10. There can be just one of these devices mounted on the heat exchanger 6, or there can be several.

Turning now to FIG. 10, there is shown the detail of the spring loaded device 131, wherein there is shown the dome 76, bolts 134 that mount the spring loaded device 131 to the dome 76 and the flange of the heat exchanger 6. The spring loaded canister 133 is shown mounted on a support housing 135 that contains a spring 136 (shown in phantom) that surrounds the tie down shaft 137. The spring 136 surrounds the tie down shaft 137 and the spring is compressible by a drive plate 138, that is forced up or down by turning the nut 139 onto the threaded end 141 of the tie down rod 137 and against the drive assembly 142, comprised of a plate 143, and a hub 144. As the nut is turned down, the spring compresses, and the pressure exerted on the housing support housing 135 is transferred to the dome 76 to maintain the dome in position.

In a like manner, the spring loaded canister 133 can be supplemented by, or substituted by hydraulic controls or pneumatic controls to achieve the same purpose. Such hydraulic controls and pneumatic controls are not shown as they are within the knowledge of one skilled in the art. This is the case when the pressure in the heat exchanger 6 is above 15 psig. For pressures above 15 psig, the heat exchanger 6 is considered by code to be an ASME pressure vessel as described Supra.

The heat exchanger 6 is encased in a steel shell 44. As known by those skilled in the art, the steel shell 44 covers essentially the entire outside surface of the heat exchanger. Also, those skilled in the art are aware of the need for end housings 51 which are formed in a unitary shell at the outer face of tube sheets to direct fluid flow to or from a respective tube sheet. In the instant embodiment and with respect to bottom tube sheet 34, air manifold 5 serves this purpose. End housing 51, a partial of which is shown in FIG. 5, is provided for top tube sheet 39 to direct gas flow from the interior of tubes 36 to stack 3. To allow for vertical expansion of the ceramic components within the interior of heat exchanger 6, steel shell 44 is provided with a circumferential discontinuity or channeled opening 50 at each tube sheet 34 and 39, configured by the insulating firebrick coverings 42 and 43, the outside edge of the tube sheet at 52, and the steel shell 44. With reference to FIG. 6, each tube sheet 34 and 39 must have an additional seal 41 around the outside of the tube sheet 34 and 39 such that when the tube sheets 34 and 39 expand outwardly into the channeled opening 50 (shown as being filled with refractory material 49 in FIG. 6), three-point seal 41 will prevent leaks around the tube sheets 34 and 39, and thereby enhance the efficiency of the unit. Seal 41 is a ceramic, crushable, gasket at the outside edge of each respective tube sheet 34, 39 and lies in channeled opening 50.

Returning now to FIG. 5, there is also shown an ambient air inlet 53 that is used to convey ambient air into the air side of heat exchanger 6, and an exit port 54 that is used to allow hot air to move from the interior of the heat exchanger 6. There is further shown two baffles 55 which are used to mix the incoming air such that that air side air temperature is more uniform before it exits the unit. Although the heat exchanger is illustrated as having two baffles 55, it is preferred that there is a sufficient number of baffles 55 present such that an odd number of passes of the air over the ceramic tubes 6 occurs to create the most beneficial mixing. Air flow can be from top to bottom, or from bottom to top, depending on the arrangement of the components of the invention.

The top tube sheet 39 is capable of being detached from the remainder of the heat exchanger 6, in order to be able to service the heat exchanger 6. For this purpose, the tube sheet 39, along with the end housing 51 is capable of being removed from the unit. This can be accomplished by simply lifting the unit or, as preferred in this invention, the tube sheet 39 can be swung up and away from the ceramic tubes 36. Since the baffles 55 will hold the ceramic tubes 36 in essentially their existing positions, individual ceramic tubes 36 can be replaced and the tube sheet 39 swung back down to cap the heat exchanger 6 once again.

It should be noted that what has been described supra for the operation of the heat exchanger is only one mode, and the preferred mode in which the heat exchanger can be used. The particular process may lend itself to an offset version of the heat exchanger, wherein the hot flue gases are moved across the ceramic tubes 36 to the exhaust stack 7 and the hot air can be moved through the ceramic tubes 36 and then into the evaporator 8.

Turning now to the evaporator 8, and with reference to FIGS. 11 and 12, there is shown an evaporator unit 8, wherein there is also shown a control panel 9, liquid leachate 25 in the tank or reservoir 56, a solids discharge apparatus 10 comprised of a conveyor housing 57, a conveyer auger 58 (in phantom), an auger motor 71, a sludge drain 59, and a receptacle 60 for the solids 61 from the bottom of the reservoir 56 which are conveyed by yet another auger system 72 using an auger motor 73 and a drive system 74. Shown at 13 is the line for conveying heated air from the heat exchanger 6 to the heating tubes 70 in the reservoir 56 through ports 67. The heated air exits into the liquid 25 by means of ports 62 in the heating tubes 70, interior of the reservoir 56. The exiting hot air heats and carries with it the volatile or vaporous materials 65 from the liquid 25 and the same exits through exhaust 12.

Also shown, is a liquid level sensor 63, which controls the amount of liquid 25 that is maintained in the reservoir 56. During the evaporation processing, a certain amount of the liquid 25 rises to surface of the pool within the reservoir 56 as oil, and this oil is removed from the surface of the liquid 25 by means of an oil overflow valve 64 as needed.

With reference to FIG. 12, there is shown an end view of the reservoir 56 sitting on a concrete support pad 68, with the end panel 69 (FIG. 11) of the reservoir 56 removed to show the internal configuration, which is the heating tubes 70, a wall of insulation 66, and the inlet ports 67 that allow the hot air from the heat exchanger 6 to enter the heating tubes 70.

Turning now to the detail of the turbine aspect of this invention, there is shown in FIG. 13, a full view of the stacked burner unit 1, the air manifold 2, the two stage oxidizer 4, the air manifold 5, the all ceramic heat exchanger 6, and the stack 7, and in addition, there is inserted between the ceramic heat exchanger 6 and the stack 7, at least one additional heat exchanger 75. Heat exchanger 75 may be all-ceramic, metal, or a composite of the two, depending of the requirements of the specific application. All-ceramic heat exchanger 6 is now converted such that the air to be heated flows around the outside of the ceramic tubes 36, and the hot flue gas flows through the ceramic tubes 36. The added heat exchanger(s) 75 receives high temperature heated air from the all-ceramic heat exchanger 6 and supplies medium high temperature heated air back to the all-ceramic heat exchanger 6 through conduit 76.

A flow of high temperature air, on the order of 1800 to 1900° F., is conveyed to the turbine 77 from the all-ceramic heat exchanger, which high temperature air is conveyed by a conduit 78. There is a compressor 79, which is driven by the turbine 77 whereupon the compressor 79 supplies low temperature, heated air to the metal heat exchanger 75. Ambient air is also supplied to the compressor 79. There is a means for supplying high temperature heated air from the turbine 77 to the evaporator 8, a means for conveying low temperature heated air from the compressor 77 to the metal heat exchanger 75, a means for conveying medium temperature heated air from the metal heat exchanger 75 to the all-ceramic heat exchanger 6, and a means of mixing medium temperature heated air from the metal heat exchanger 75, and ambient air, and conveying that air mixture to the staged oxidizer 4.

The system used to dispose of landfill gases and leachate described above can be configured to produce energy extremely efficiently by including at least one external combustion engine 84 in the system. The preferred external combustion engine 84 is a commercially available heat engine that employs a gaseous working medium sealed within the machine. A portion of this engine is maintained at a high temperature using the flue gas stream from the burner 1 or oxidizer 4, or by using hot clean air from the all-ceramic heat exchanger 6. Another portion of the engine is maintained at a constant low temperature, and the gaseous working medium is transferred between the hot and cold portions by movement of the engine's pistons. Thermal expansion at the hot end drives the pistons toward the cold end, compressing cold gas beneath the pistons. The reciprocating motion of the pistons powers the generator, and a regenerator is used between the hot and cold portions to increase efficiency. External combustion engine 29 requires hot side input temperatures of approximately 1800 degrees F. for proper function, and discharges gas at a moderate temperature, approximately 1500 degrees F.

The system can be configured to produce energy in many ways, depending on the requirements of the specific application. One possible configuration will now be described with respect to FIG. 16, wherein the combustion products from the burner 1 are oxidized within staged oxidizer 4. Note that discharge from oxidizer 4 is sent at approximately 2400 degrees F. to the tube-side of all-ceramic heat exchanger 6. Within all-ceramic heat exchanger 6, tube-side combustion flue gas transfers heat energy to air-side clean air, providing clean hot air at temperatures of approximately 1900 degrees for use in firing external combustion engine 29. Tube-side discharge from all-ceramic heat exchanger 6 can be directed to the tube-side of at least one additional heat exchanger 75. Heat exchanger 75 may be all-ceramic, metal, or a composite of the two, depending of the requirements of the specific application. Within heat exchanger 75, tube-side flue gas transfers heat energy to air-side clean air, providing a preheated clean air for input to all-ceramic heat exchanger 6, and/or a source of hot clean air for use in an external process 5. Moderately hot air discharged from external combustion engine 29 is directed to evaporator 8 for use in drying leachate.

Claims

1. An all-ceramic heat exchanger comprising

(i) an elongate body, the body having a first end and a second end,
(ii) a plurality of ceramic tubes extending from the first end to the second end,
(iii) a first sprung jack arch tube sheet for supporting ceramic tubes positioned adjacent the first end, the first sprung jack arch tube sheet being fixed with respect to the body,
(iv) a second sprung jack arch tube sheet for supporting ceramic tubes positioned adjacent the second end, the second sprung jack arch tube sheet being movable with respect to the body,
(v) at least one baffle positioned between the first end and the second end for directing air flow within the all-ceramic heat exchanger,
wherein the first end terminates in a first dome, and wherein the second end terminates in a second dome.

2. The all-ceramic heat exchanger of claim 1 wherein the all-ceramic heat exchanger is oriented such that

(a) the second end is in vertical alignment with the first end, and
(b) the second end generally overlies the first end,
wherein the expansion of the ceramic tubes during use causes upward movement of the second sprung jack arch tube sheet such that the distance between the second sprung jack arch tube sheet and the first sprung jack arch tube sheet is increased, and
wherein the second sprung jack arch tube sheet is maintained in a sealing relationship with the ceramic tubes by force of gravity acting on the combination of second dome and second sprung jack arch tube sheet at pressures of less than about 15 psig.

3. The all-ceramic heat exchanger of claim 1 wherein the all-ceramic heat exchanger is oriented such that

(a) the second end is in vertical alignment with the first end, and
(b) the second end generally overlies the first end,
wherein the expansion of the ceramic tubes during use causes upward movement of the second sprung jack arch tube sheet such that the distance between the second sprung jack arch tube sheet and the first sprung jack arch tube sheet is increased, and
wherein the second dome comprises adjustable securement means, the adjustable securement means maintaining the second sprung jack arch tube sheet in a sealing relationship with the ceramic tubes.

4. The all-ceramic heat exchanger of claim 3 wherein the adjustable securement means comprises spring loaded rods fastening the second dome to the body so as to maintain the second dome in a position abutting the body, thereby maintaining the second sprung arch jack tube sheet in a sealing relationship with the ceramic tubes.

5. The all-ceramic heat exchanger of claim 3 wherein the adjustable securement means comprises hydraulic controllers, the hydraulic controllers using hydraulic pressure to maintain the second dome in a position abutting the body, thereby maintaining the second sprung arch jack tube sheet in a sealing relationship with the ceramic tubes.

6. The all-ceramic heat exchanger of claim 3 wherein the adjustable securement means comprises pneumatic controllers, the pneumatic controllers using pneumatic pressure to maintain the second dome in a position abutting the body, thereby maintaining the second sprung arch jack tube sheet in a sealing relationship with the ceramic tubes.

7. A system for processing landfill products, the system comprising

(i) a gas burner,
(ii) a staged oxidizer,
(iii) at least one all-ceramic heat exchanger, and
(iv) a leachate evaporator,
wherein any all-ceramic heat exchanger comprises
(a) an elongate body, the body having a first end and a second end,
(b) a plurality of ceramic tubes extending from the first end to the second end,
(c) a first sprung jack arch tube sheet for supporting ceramic tubes positioned adjacent the first end, the first sprung jack arch tube sheet being fixed with respect to the body,
(d) a second sprung jack arch tube sheet for supporting ceramic tubes positioned adjacent the second end, the second sprung jack arch tube sheet being movable with respect to the body,
(e) at least one baffle positioned between the first end and the second end for directing air flow within the all-ceramic heat exchanger, and
wherein the first end terminates in a first dome, and wherein the second end terminates in a second dome,
wherein the system combusts landfill gas within the gas burner using preheated air from the all-ceramic heat exchanger, the gas burner generating combustion gas,
the combustion gas from the gas burner being oxidized within the staged oxidizer using preheated air from the all-ceramic heat exchanger, the oxidizer discharging a hot flue gas,
the hot flue gas from the oxidizer being directed through the tube side of the all-ceramic heat exchanger where heat is transferred through the ceramic tubes so as to heat clean air on the air-side of the all ceramic heat exchanger, the tube side flue gas then being discharged to the atmosphere, the heated clean air being directed from the heat exchanger to the gas burner, the oxidizer, and the evaporator, the evaporator percolating the heated clean air from the all-ceramic heat exchanger through landfill products to heat and evaporate liquids within the landfill products, and, discharging landfill gas which is directed to the gas burner, and discharging dried landfill products.

8. The system for processing landfill products of claim 7 wherein the system further comprises a turbine, a compressor, a generator, and at least one additional heat exchanger,

wherein the tube side flue gas from the all-ceramic heat exchanger is directed to the tube side of the at least one additional heat exchanger, the tube side flue gas then being discharged to the atmosphere,
wherein ambient air is compressed within the compressor, the compressor discharging heated, compressed air,
the heated compressed air from the compressor directed to the air side of the at least one additional heat exchanger,
the heated compressed air is then discharged from the air side of the at least one additional heat exchanger and is directed to the air side of the all ceramic heat exchanger where it receives additional heat energy,
the heated compressed air is then discharged from the air side the all-ceramic heat exchanger and is directed to a turbine, the heated compressed air expanding within the turbine so as to drive the generator and produce power, the expanded air being discharged to the evaporator.

9. The system for processing landfill products of claim 7 wherein the staged oxidizer is stacked on the gas burner such that it overlies the gas burner in vertical alignment with the gas burner,

wherein the all-ceramic heat exchanger is stacked on the staged oxidizer such that it overlies the staged oxidizer in vertical alignment with the staged oxidizer, the all-ceramic heat exchanger being oriented such that
(a) the second end is in vertical alignment with the first end, and
(b) the second end generally overlies the first end,
wherein the expansion of the ceramic tubes during use causes upward movement of the second sprung jack arch tube sheet such that the distance between the second sprung jack arch tube sheet and the first sprung jack arch tube sheet is increased, and
wherein the second sprung jack arch tube sheet is maintained in a sealing relationship with the ceramic tubes by force of gravity acting on the combination of second dome and second sprung jack arch tube sheet regardless of temperature of the all-ceramic heat exchanger.

10. The system for processing landfill products of claim 7 wherein the staged oxidizer is stacked on the gas burner such that it overlies the gas burner in vertical alignment with the gas burner,

wherein the all-ceramic heat exchanger is stacked on the staged oxidizer such that it overlies the staged oxidizer in vertical alignment with the staged oxidizer, the all-ceramic heat exchanger being oriented such that
(a) the second end is in vertical alignment with the first end, and
(b) the second end generally overlies the first end,
wherein the expansion of the ceramic tubes during use causes upward movement of the second sprung jack arch tube sheet such that the distance between the second sprung jack arch tube sheet and the first sprung jack arch tube sheet is increased, and
wherein the second dome comprises adjustable securement means, the adjustable securement means maintaining the second sprung jack arch tube sheet in a sealing relationship with the ceramic tubes.

11. The all-ceramic heat exchanger of claim 11 wherein the adjustable securement means comprises spring loaded rods fastening the second dome to the body so as to maintain the second dome in a position abutting the body, thereby maintaining the second sprung arch jack tube sheet in a sealing relationship with the ceramic tubes.

12. The all-ceramic heat exchanger of claim 11 wherein the adjustable securement means comprises hydraulic controllers, the hydraulic controllers using hydraulic pressure to maintain the second dome in a position abutting the body, thereby maintaining the second sprung arch jack tube sheet in a sealing relationship with the ceramic tubes.

13. The all-ceramic heat exchanger of claim 11 wherein the adjustable securement means comprises pneumatic controllers, the pneumatic controllers using pneumatic pressure to maintain the second dome in a position abutting the body, thereby maintaining the second sprung arch jack tube sheet in a sealing relationship with the ceramic tubes.

14. A all ceramic heat exchanger comprising in combination:

(i) a metal jacketing and support frame having a top end and a bottom end;
(ii) a lower fixed sprung arch tube sheet mounted in the bottom end of the metal support frame for supporting:
(iii) multiple ceramic heat exchanger tubes fitted into openings in the lower fixed sprung arch tube sheet;
(iv) a moveable upper sprung jack arch tube sheet mounted in the top end of the metal support frame such that the ceramic heat exchanger tubes of (iii) are fitted into respective openings in the moveable upper sprung jack arch tube sheet, said moveable upper sprung jack arch tube sheet having an outside edge surface;
(v) a ceramic gasket mounted on the outside edge surface of the moveable upper sprung jack arch tube sheet;
(vi) a means for entry of air or gas into the ceramic heat exchanger;
(vii) a means for exit of air or gas out of the heat exchanger;
(viii) at least one air baffle mounted in the interior of the heat exchanger.

15. A system for handling landfill produced products said system comprising in combination:

(A) a housing and support frame having a top, a bottom and a middle section;
(B) supported in the bottom of the support frame, a gas burner assembly having a top end, bottom end, and a middle zone;
(C) supported in the middle section of the support frame, and mounted on the top of the gas burner assembly, a staged oxidizer unit having a bottom section, an upper section, and a middle section, said upper section of the staged oxidizer unit having a top end, said top end of said upper section of the staged oxidizer unit having mounted therein an air manifold assembly, said bottom and middle section of the staged oxidizer being fitted with a multiplicity of air conveyance ceramic tuyeres;
(D) means for conveying and controlling air to the staged oxidizer through the tuyeres and the air manifold assembly;
(E) mounted on the upper end of the staged oxidizer unit, an all-ceramic heat exchanger;
(F) mounted on the all-ceramic heat exchanger, a stack for conveying products of combustion from the burner, staged oxidizer and all-ceramic heat exchanger to the atmosphere;
(G) an evaporator for heating and evaporating liquid materials, said evaporator being heated by percolating high temperature air through liquid materials contained therein;
(H) a means for conveying air to the all-ceramic heat exchanger;
(I) a means for conveying heated air from the all-ceramic heat exchanger to the evaporator;
(J) means for conveying volatile products from the evaporator to the burner and the staged oxidizer;
(K) means for supplying liquid materials to the evaporator;
(L) means for controlling the system.

16. A process for handling landfill produced products, said process comprising:

(I) providing a burner that will burn landfill produced gases, said burner having a top and a bottom;
(II) feeding landfill produced gases to the burner along with controlled amounts of preheated combustion air to provide a zone temperature in the burner of not more than about 2200° F.;
(III) moving the products of combustion from (II) to a staged oxidizer having a bottom, and mixing said products of combustion with heated vapors from an evaporator capable of heating and evaporating liquid landfill produced products, such that the zone temperature in the bottom of the staged oxidizer is in the range of about 1600° F. to about 2200° F.:
(IV) providing a means of introducing air to the staged oxidizer essentially throughout the length of the staged oxidizer;
(V) mixing the products of (III) with the air in (IV) as the products move through the staged oxidizer;
(VI) allowing the mixture from the staged oxidizer to exit into a multiplicity of ceramic tubes in an all-ceramic heat exchanger, and then through the heat exchanger tubes to exit through the stack to the atmosphere;
(VII) supplying landfill produced liquid material to an evaporator,
(VIII) while carrying out steps (I) to (VI), providing a controlled amount of air into the interior of the all-ceramic heat exchanger to move in and around the ceramic tubes of the all-ceramic heat exchanger using at least one air baffle in the heat exchanger, to heat said air to a temperature of about 1200° F. to about 1800° F.;
(IX) allowing the heated air to exit from the all-ceramic heat exchanger and conveying said heated air to the evaporator and percolating said heated air into any liquid material present in the evaporator:
(X) collecting and conveying the evaporate from the evaporator to the burner to provide a portion of the fuel for the burner;
(XI) while moving the evaporate to the burner, separating a small portion of the evaporate and conveying it to the bottom of the staged oxidizer to mix as in step (III).

17. A system for handling landfill produced products, said system comprising in combination;

(A) a housing and support frame having a top, a bottom and a middle section;
(B) supported in the bottom of the support frame, a gas burner assembly having a top end, bottom end, and a middle zone;
(C) supported in the middle section of the support frame, and mounted on the top of the gas burner assembly, a staged oxidizer unit having a bottom section, an upper section, and a middle section, said upper section of the staged oxidizer unit having a top end, said top end of said upper section of the staged oxidizer unit having mounted therein an air manifold assembly, said bottom and middle sections of the staged oxidizer being fitted with a multiplicity of air conveyance ceramic tuyeres;
(D) means for conveying and controlling air to the staged oxidizer through the tuyeres and the air manifold assembly;
(E) mounted on the upper end of the staged oxidizer unit, a all-ceramic heat exchanger;
(F) mounted on the all-ceramic heat exchanger, a stack for conveying products of combustion from the burner, staged oxidizer and all-ceramic heat exchanger to the atmosphere;
(G) an evaporator for evaporating liquid materials, said evaporator being heated by percolating medium high temperature air through liquid materials contained therein;
(H) a metal heat exchanger, said metal heat exchanger receiving high temperature heated air from the all-ceramic heat exchanger and supplying medium high temperature heated air to the all-ceramic heat exchanger;
(I) a turbine, said turbine being driven by high temperature heated sir from the all-ceramic heat exchanger;
(J) a means for conveying high temperature heated air from the all-ceramic heat exchanger to the turbine;
(K) a compressor, said compressor being driven by the turbine and said compressor supplying low temperature heated air to the metal heat exchanger;
(L) a means of supplying ambient air to the compressor;
(M) a means of conveying medium high temperature heated air from the turbine to the evaporator;
(N) means for conveying volatile products from the evaporator to the burner and the staged oxidizer;
(O) means for conveying low temperature heated air from the compressor to the metal heat exchanger;
(P) means for conveying medium temperature heated air from the metal heat exchanger to the all-ceramic heat exchanger;
(Q) a means of mixing medium temperature heated air from the metal heat exchanger, and ambient air, and conveying said air mixture to the staged oxidizer and,
(R) a means for controlling the system.

18. A process for handling landfill produced products, said process comprising:

(I) providing a conventional burner that will burn landfill produced gases, said burner having a top and a bottom;
(II) feeding landfill produced gases to the burner along with controlled amounts of preheated combustion air to provide a zone temperature in the burner of not more than about 2200° F.;
(III) moving the products of combustion from (II) to a staged oxidizer having a bottom, and mixing said products of combustion with heated vapors from an evaporator capable of heating and evaporating liquid landfill produced products, such that the zone temperature in the bottom of the staged oxidizer is in the range of about 1600° F. to about 2200° F.;
(IV) providing a means of introducing air to the staged oxidizer essentially throughout the length of the staged oxidizer;
(V) mixing the products of (III) with the air in (IV) as the products move through the staged oxidizer;
(VI) allowing the mixture form the staged oxidizer to exit into a multiplicity of ceramic tubes in an all-ceramic heat exchanger, and then through the all-ceramic heat exchanger tubes to a metal heat exchanger and then exit through a stack to the atmosphere;
(VII) while carrying out steps (I) to (VI), providing a controlled amount of air into the interior of the all-ceramic heat exchanger to move in and around the ceramic tubes of the all-ceramic heat exchanger using at least one air baffle in the all-ceramic heat exchanger, to heat said air to a temperature of about 1200° F. to about 1800° F.;
(VIII) allowing the heated air to exit from the all-ceramic heat exchanger and conveying said heated air to a turbine, thereby driving the turbine;
(IX) conveying the heated air from the turbine to an evaporator and percolating said heated air into any liquid material present in the evaporator;
(X) collecting and conveying the evaporate from the evaporator to the burner to provide a portion of the fuel for the burner;
(XI) while moving the evaporate to the burner, separating a small portion of the evaporate and conveying it to the bottom of the staged oxidizer to mix as in step (III).
Patent History
Publication number: 20080118310
Type: Application
Filed: Nov 15, 2007
Publication Date: May 22, 2008
Inventor: Robert G. Graham (Presque Isle, MI)
Application Number: 11/985,385
Classifications
Current U.S. Class: Landfill (405/129.95); Means For Cleaning By Combustion (110/236)
International Classification: F23G 7/06 (20060101);