HK1163208B - Heater and method for recovering hydrocarbons from underground deposits - Google Patents

Description

Heater and method for recovering hydrocarbons from underground deposits

Cross Reference to Related Applications

The instant invention claims the benefit of co-entitled U.S. provisional application serial No. 61/112,088, filed on 6/11/2008, the disclosure of which is incorporated herein by reference in its entirety.

Technical Field

The present invention relates generally to an apparatus and method for facilitating recovery of hydrocarbon products from underground deposits, and more particularly to a method and system for heating oil shale in situ to recover liquid shale oil.

Background

A large number of underground oil shale deposits are found in the united states and around the world. These oil shale deposits are characterized by their solid state, as compared to petroleum deposits, in which the organic material is a polymer-like structure, commonly referred to as "kerogen", intimately mixed with inorganic mineral components. It has been shown that heating oil shale deposits to a temperature of about 300 ℃ causes pyrolysis of solid kerogen, forming petroleum-like "shale oil" and natural gas-like gas products. Economic extraction of oil shale-derived products is hindered, in part, by the difficulty of efficiently heating underground oil shale deposits.

Thus, there is a need in the art for methods and apparatus that allow for efficient in situ heating of large volume (volume) oil shale deposits.

Disclosure of Invention

The present application addresses some of the shortcomings of known systems and techniques by providing an apparatus that heats over a large subsurface volume. In one embodiment, a heater is provided that can be heated along its length to a specified temperature.

Generally, the heater receives a fuel and an oxidant and is designed to promote an exothermic reaction zone along its length. In various embodiments, the heater includes a mixing zone for the fuel and the oxidant, and the reaction within the mixture occurs on the mixing zone, the catalytic surface, or some combination thereof.

These features and various additional configurations (accessories) and features that will be apparent to those skilled in the art from the following detailed description are obtained by the apparatus and method of the present disclosure and its preferred embodiments as set forth herein.

Drawings

FIG. 1 is a schematic illustration of an oil shale rich site in the Green River Formation (Colorado's Green River Format) of Colorado;

FIG. 2 is a schematic diagram of some of the elements that may be included in a Heater Control Building (Heater Control Building) for Heater Control;

FIG. 3 is a schematic diagram illustrating an exemplary embodiment of a heater in the form of a Permeable Catalytic material heater (Permeable Catalytic Material Heater);

FIG. 4 is a schematic diagram showing another exemplary embodiment of a Heater in the form of a Catalytic Bed Heater (Catalytic Bed Heater);

FIG. 5 shows the temperature distribution from a numerical simulation of the catalytic bed heater performance shown in FIG. 4; and

FIG. 6 is a schematic diagram of yet another exemplary embodiment of a Heater in the form of a Catalytic-Wall Heater.

Detailed Description

Fig. 1 is an elevation view of an oil shale rich site 100 in colorado, known as the green river formation. Fig. 1 is an exemplary, non-limiting illustration. Some of the layers shown in this elevation include a sulfonic acid Zone (Mahogany Zone)102, a nahcolite-rich oil shale Cap Rock (Cap Rock Layer)104, and an Illite-rich oil shale Zone 106 with increasing depth. The distances shown are approximate and roughly illustrate the geology of the formation. The water quality in the region above the sulfonic acid band 102 is generally good. The salinity of the water increases as it approaches the nahcolite-rich oil shale cap rock layer 104. The permeability of the illite-rich oil shale zone 106 is low.

One example method of in situ extraction of kerogen includes heating the illite-rich oil shale zone 106 to pyrolysis temperatures. Heat may be provided by a heat source via heater well 108. Fluid kerogen may be removed via production wells 110. In Situ Extraction is further described In co-pending U.S. patent application Ser. No. 11/655,152, entitled "In-Situ Method and System for Extraction of Oil From Shale," filed on 2007, 1/19, which is incorporated by reference as if fully set forth herein. It can be seen that both heater well 108 and production well 110 have well sections (sections) extending within illite-rich oil shale zone 106. Although shown as a horizontal well section, the well may be horizontal, vertical, or any angle therebetween.

In one embodiment, the heater well 108 may include a counter-flow heat exchanger to preheat a combustible fluid (described more fully below) and then combust the combustible fluid to generate heat in the illite-rich oil shale zone 106. In another embodiment, the heater well 108 may include downhole burners within the illite-rich oil shale zone 106. Heater wells 108 provide heat for pyrolyzing the shale so that the kerogen is converted into a fluid that can be extracted through production wells 110. In various embodiments, combustible fluid supplied to the heater well, including oxygen-rich and/or carbon dioxide-containing mixtures, may be recovered at the surface from either the production well 110 or the heater well 108. In this context, the term fluid is intended to include both liquids and gases.

The volume of shale used as the heating target is called the "distiller (retort)". The heater converts the deposit into recoverable hydrocarbon liquids and gases by transferring heat in the deposit by conduction and convection between the heated fluid and the distiller volume to form a subsurface distiller in the deposit. Thus, for example and without limitation, oil shale may be pyrolyzed to form synthetic crude oil (synthetic crude oil), which may then be extracted through another well. In some embodiments, for example, the distiller can extend from 50ft to 100ft from the heater.

The temperature required to facilitate removal of the underground deposit depends on the chemical and/or physical state and depth of the deposit. In general, the heaters disclosed herein may be configured to operate over a range of temperatures as well as a range of depths and configurations to facilitate the removal of many types of deposits, including but not limited to shale, tar sands, and heavy oil deposits. The examples set forth herein are for illustration, and are not intended to be limiting. In one embodiment, the heater temperature is above the pyrolysis temperature of kerogen, but below the temperature at which the shale oil chars on the heater surface.

Because oil shale deposits typically contain large amounts of inorganic materials mixed with kerogen and these inorganic materials are heated along with the kerogen, it is desirable that the distiller can heat efficiently. One efficient heating method for recovering shale oil is to drill one or more wells in a shale bed and install downhole heaters in the one or more wells that heat the oil shale in situ, thereby pyrolyzing kerogen into liquid and gaseous products that can be recovered through one or more production wells.

If the deposits in the retort area have consistent physical and chemical properties, and if the heating is uniform along the heater, the retort will form uniformly along the heater. Thus, for example, a long straight heater producing uniform heating would form a cylindrical retort. Longitudinal heating variations may result in non-cylindrical retort shapes. Such changes in the shape of the retort may create a system that cannot efficiently process all of the oil shale near the retort and may require the heater to be turned off before restoring homogeneity. For this reason, it is preferred that the heating is such that the radial extension of the retort does not vary significantly along the length of the heater.

Fig. 1 also shows a heater control building 112 and a shale oil recovery building 114. In one embodiment, the distiller heating is achieved by underground reaction of fuel and oxidant. Alternatively still heating may be supplemented by electrical heating of a heater. Fig. 2 is a schematic diagram of some of the elements for heater control that may be included within heater control building 112. The heater control building 112 may include: a controller 200, one or more adjustable valves 202(1) -202(N) connecting a fuel supply 204 and a heater fuel line 206, one or more adjustable valves 203 connecting an oxidant supply 208 and an oxidant line 207, and one or more adjustable valves 205 connecting a diluent source 210 and a diluent supply line 209. Adjustable valves 203 and 205 may be arranged similar to the manifold associated with adjustable valve 202. The heater control building 112 may also include devices or mixing fluids (not shown). For example, some embodiments may provide a premixed fuel, oxidant, diluent, or mixture thereof.

In one embodiment, the fluid is controllably provided to different zones of the heater well 108, as described subsequently. Thus, for example and without limitation, the supply of fuel, oxidant and/or diluent may be independently regulated and may be provided to different portions of the heater ("heater zones") via piping means (manifolds). In yet another embodiment, a temperature sensor device is provided along the length of the heater. For example, thermocouples or Resistance Temperature Detectors (RTDs) are strategically placed along, near, or on the outer surface of the heater. The heater can be operated to achieve temperature uniformity by appropriate adjustment of the fuel supply. Optionally, additional heating may be provided using resistive heaters to achieve temperature uniformity along the heater.

In one embodiment, the temperature variation along the heater is no greater than 10 ℃. In another embodiment, the temperature variation along the heater is no greater than 20 ℃. In yet another embodiment, the temperature along the heater does not vary by more than 10 ℃ over a 10 meter length of the heater. In another embodiment, the temperature along the heater does not vary by more than 20 ℃ over a 10 meter length of the heater. In another embodiment, the temperature variation along the length of the heater is less than 40 ℃. In yet another embodiment, the temperature variation along the heater is less than 100 ℃.

In one embodiment, the heat flux along the heater varies by no more than 10%. In another embodiment, the heat flux along the heater varies by no more than 20%. In yet another embodiment, the heat flux along the heater varies by no more than 10% over a 10 meter length of the heater. In another embodiment, the heat flux along the heater does not vary by more than 20% over a 10 meter length of the heater. In yet another embodiment, the distiller may not have constant heat transfer characteristics. Thus, for example, the flow of oil vapor may increase heat transfer on some portions of the heater. Heat transfer variations can be counteracted by intentionally providing a heat flux and/or temperature variation in the longitudinal or circumferential direction.

In one embodiment, the heater is sized to fit within a perforated well casing within a retort. The perforated casing provides mechanical protection against fragmented rock fragments that may fall off the borehole wall. Thus, for example, the heater is sized to fit within a well casing having a circular orifice diameter of 150mm to 500 mm. In various embodiments, the heater is cylindrical and has a diameter of 150mm to 300 mm. In various embodiments, the heater diameter is approximately 150mm, approximately 200mm, approximately 250mm, or approximately 300 mm.

Studies have shown that the extraction yield from oil shale deposits increases with the distiller side length, i.e. the longer a heater well can supply a distiller, the less cost is incurred by the significant cost of the well. The disclosed heater can heat a very long distiller to a uniform temperature. In one embodiment, the heater length is, for example and without limitation, greater than 1000 m. In alternative embodiments, the heater length is greater than 100m, greater than 200m, greater than 300m, greater than 400m, greater than 500m, greater than 600m, greater than 700m, greater than 800m, or greater than 900 m. In other alternative embodiments, the heater length is greater than 1500m or greater than 2000 m.

The conversion of kerogen in oil shale deposits into liquid and/or gaseous products by pyrolysis also facilitates the separation of organic components from the bulk of the shale inorganic components present.

In one embodiment, a heater for subsurface heating of shale, tar sands, and heavy oil deposits is provided. The heater may be installed in a horizontal well, for example. After heating, the deposit forms a boiling oil (boiling oil) maintained at a temperature that depends on the deposit composition and depth. For many underground deposits, the temperature of interest is 275 ℃ to 450 ℃. In one embodiment, the oil boils at about 350 ℃.

In another embodiment, the heater may be installed in a horizontal well that traverses a deposit, such as an oil shale deposit. In another embodiment, the product in contact with the heater liquefies as a result of heating and/or pyrolysis and forms a boiling liquid in contact with a length of the heater. In one embodiment, the deposit is heated to a boiling point, which will vary with deposit type and depth. Thus, for example, it is preferred that the heater be surrounded by a subsurface boiling product oil maintained at approximately 350 ℃ upon operation.

In yet another embodiment, the heater comprises a counter-flow heat exchanger. The heater is supplied with a gaseous or liquid fuel and a gaseous oxidant, which may be diluted and may be premixed or supplied separately. The fuel and oxidant react exothermically and form a "flue gas" that flows counter-currently through the heat exchanger and preheats the incoming gas. The released heat preheats the incoming fuel and/or oxidant and/or diluent and the housing of the heater. Heating may occur over some or all of the length of the heater. In certain other embodiments, the fuel and oxidant react within the heater, in the gas phase, or on a catalyst-promoted surface. The resulting flue gas flows counter-currently to the incoming fluid, preheating the fuel and oxidant as they flow into the burner, and heating the outer tube of the heater.

In one embodiment, the supply from the surface to the heater and the flue gas duct are arranged so as to provide a counter-flow heat exchanger. The flue gas is thus cooled to, for example, approximately 25 ℃ upon reaching the surface, and the fuel and oxidant are preheated to a maximum flue gas temperature, which is, for example, approximately 400 ℃, or approximately 500 ℃, before entering the heater.

In certain embodiments, the fuel and oxidant may include a stoichiometric or lean (oxidant rich) ratio in various embodiments. In some embodiments, the fuel and oxidant are premixed, while in other embodiments, the fluids are supplied separately and mixed in a reaction zone along the heater. Alternatively, a diluent may be added to the fuel, oxidant, or mixture thereof. The diluent may be, but is not limited to, carbon dioxide recovered at the surface from a production well.

In certain other embodiments, particularly those in which the fuel/oxidant reaction within the heater is not sufficiently complete for the flue gas to meet emissions or sequestration (sequestration) requirements, a catalytic converter may be provided at the flue gas outlet of the heater to eliminate residual hydrocarbons and CO in locations at temperatures high enough to support catalytic oxidation.

In other embodiments, some of the flue gas may be recycled back to the heater by mixing it with fuel, oxygen, or a mixture thereof.

Several heater embodiments are described below, which should not be construed as limiting.

Permeable catalytic material heater

Fig. 3 illustrates one embodiment of a heater, which is a permeable catalytic material heater 300. The heater embodiment of fig. 3 may include one or more of the elements described above, as appropriate. The heater of fig. 3 has an open end 302 and a closed heater end 304, the open end 302 having a gas inlet/outlet portion 306 providing gas inflow (inflow) and outflow (outflow). The heater 300 includes an elongated burner housing 308 adapted to be positioned in a well. Inside the burner housing 308 is a Flow Restriction Medium 310 that extends to the heater closed end 304. In this example embodiment, the flow restriction medium 310 divides the interior volume of the combustor casing 308 into an inner flow channel 303 and an outer flow channel 305, which are sometimes referred to as a first casing region and a second casing region. At least a portion of the flow restriction medium 310 is formed of a permeable catalytic material that utilizes a selected permeability to provide controlled cross flow of the inner flow channel to the outer flow channel. While the embodiment of fig. 3 shows a cylindrical burner housing and a cylindrical flow restricting medium, this configuration is for illustration and is not limited to this configuration. In an alternative embodiment, the outflow channel extends along the heater, but does not include the heater closed end. In another alternative embodiment, the cross flow travels from the outer flow channel to the inner flow channel.

A premixed fluid comprising fuel and oxidizer is provided through the well from the surface into the gas inlet/outlet portion 306 and flows through the inner flow channel 303 toward the heater closed end 304 as indicated by axial arrow 302. The premixed gases may be stoichiometric or lean and may include diluents to reduce the reaction temperature. The diluent may be recovered flue gas, inert gas recovered from the production well, or other non-reactive gases such as nitrogen contained in air.

The premixed fluids also flow through the permeable catalytic material 310 as indicated by radial arrows 330, where they react to form flue gas that flows away from the heater closed end 304 as indicated by axial arrows 340. The flow distribution through the permeable catalytic material 310 is affected by the fluid properties and pressure as well as the porosity, thickness and area of the permeable catalytic material. The heat of reaction of the premixed fluid heats the flow restriction medium 310, the premixed fluid, the flue gas, and the housing 308. Complete reaction of the premixed fluid in the catalytic material is desirable to achieve maximum temperature rise throughout the catalytic material. The large pressure drop through the catalytic material promotes an axial distribution of the premixed fluid that should be uniform in order to uniformly heat the heater 300.

The flue gas flows from the flow restricting medium 310 through the outer flow channel 305 to the gas inlet/outlet portion 306 and finally through the well and to the surface.

In one embodiment, the fuel and oxidant flow through the flow restriction medium 310 is approximately constant along the length of the combustor. Thus, for example and without limitation, the flow rate varies by less than 5% along the length of the burner except near the end of the burner. In another embodiment, the flow rate varies by less than 2%.

The flow restriction medium 310 provides a means for achieving a desired controlled transverse flow pattern along the length of the heater between the inner and outer flow channels. The flow restriction medium 310 may be continuous or discontinuous, composed of porous and non-porous segments, composed of porous panels in different solid tube walls, or any combination of the foregoing. In other embodiments, the porous face plate may be made of sintered metal frit (frit), ceramic frit, or small holes in the walls separating the inner and outer flow channels.

In one embodiment, small flow rate variations through the flow restriction medium 310 and along the combustor 300 are provided by a flow restriction medium having an approximately constant permeability through which a pressure drop is greater than a pressure drop along the outer flow channel 305. Alternatively, small flow rate variations through the flow restriction medium 310 and along the burner 300 are provided by the flow restriction medium 310 having a permeability that increases with distance along the burner, matching the pressure drop through the flow restriction medium to the pressure as it varies along the outer flow channel 305. In yet another embodiment, a small flow rate is provided by a uniformly permeable material having different areas along the length of the flow restriction medium, thereby matching the pressure drop between the inner and outer flow channels.

In one embodiment, the permeable catalytic material portion of the flow restriction medium 310 has a diameter of 200mm and a wall thickness of a few millimeters (e.g., 10 mm). The housing 308 is, in one embodiment, a stainless steel tube having a diameter of approximately 300 mm. The permeable catalytic material may be, for example, but not limited to, sintered stainless steel or special alloy steel. Alternatively, the catalytic material comprises a noble metal such as palladium or platinum on sintered alumina. The permeable catalytic material may have a permeability constant of, for example, but not limited to, 0.1 to 10mDarcy (millidarcy). These values are merely illustrative, and the actual values for distributing the premixed gas reaction are selected so that the housing maintains an approximately constant temperature.

In one embodiment, the premix fluid comprises a gaseous stoichiometric fuel/oxidant mixture containing 2 wt% CH₄And 8 wt% O₂The adiabatic temperature rise was about 900 ℃.

In another embodiment, the premixed fluid is lean, wherein CH₄Flow rate of 0.02kg/s, O₂The flow rate was 0.08 kg/s. This mixture is further diluted by adding 1.0kg/s of an inert gas, which may be, for example and without limitation, CO₂、H₂O or N₂. The premixed gas is provided at low temperature (near room temperature) and high pressure (near 30 atm). The flue gas outlet pressure is 15-20 atm, and the sleeve is maintained at about 410 ℃ to maintain the boiling oil pool outside the tube at about 400 ℃.

As the premixed fluid flows through the inner flow channel 303, the counter-flow arrangement of premixed fluid and flue gas heats the premixed fluid by the returning hot flue gas in the outer flow channel 305 and to a temperature that does not vary significantly with the length of the burner. In one embodiment, the premixed fluid is heated to a temperature of approximately 400 ℃ at a short distance into the heater.

As the premixed fluid flows down the heater, the fluid penetrates the catalytic material and undergoes a catalytically activated exothermic reaction of the fuel and oxidant. The heat released by this reaction raises the catalytic material to an approximately constant temperature along the length of the burner. In one embodiment, the catalytic material reaches a temperature of about 450 ℃.

Another embodiment involves recycling a portion of the exiting flue gas to the inlet or feed side. In this embodiment, 1.0kg/s of flue gas is passed throughThe recirculating ejector compressor recirculates. The motive gas (motive gas) of the ejector may be an oxidant or fuel supply, such as oxygen feed or CH₄Feeding. In gas recirculation embodiments, the permeability of the catalytic material should be high to reduce the overall pressure drop. Thus, for example and without limitation, permeability may vary between 1.0mDarcy at the inlet and 100mDarcy towards the closed end of the combustor.

In one embodiment, the inner tube is electrically conductive and can be electrically heated along its length to provide an external heat source for initially raising the heater temperature high enough to activate the catalytic surface.

In one embodiment, a pilot burner (pilot burner) near the inner tube inlet provides a heat source for initially raising the heater temperature high enough to activate the catalytic surface.

Burner of catalytic bed heater

Fig. 4 shows another heater embodiment, which is a catalytic bed heater 400. The heater embodiment of fig. 4 may include one or more of the elements described above, as appropriate. The heater 400 of fig. 4 provides a plurality of discrete reaction zones 450. As described below, the heater 400 of fig. 4 has a near stoichiometric fuel and oxidant mixture. The oxidant may be a pure oxidant, such as pure oxygen, or may include a non-reactive diluent. In each reaction zone, a portion of the fuel is mixed and reacted with the oxidant to produce a more dilute oxidant mixture. In the last reaction zone, the last fuel reacts with the last oxidant to form flue gas.

In one embodiment, each of the plurality of reaction zones is supported by a catalytic bed 455, represented by, but not limited to, "Honeycomb Catalyst". Honeycomb catalysts are structures having a number of parallel flow channels that are aligned to allow gas to flow through the structure. The flow channels may be hexagonal or have other cross-sectional areas that allow the structures to be regularly packed. The honeycomb is formed from or coated with a catalytic material. Such catalysts are used, for example, as automotive catalytic converters. Alternatively, the catalytic bed 455 may be comprised of catalytic pellets, or extrudates.

Reaction zone 450 is located in the region where the oxidant flows. Fuel is supplied to each reaction zone through a separate fuel line 452 terminating in a nozzle or injector 454, which nozzle or injector 454 facilitates mixing of the fuel and oxidant prior to entry into the associated catalyst bed 455. The fuel reacts with oxygen in the catalyst to form a mixture of flue gas and residual oxygen. Additional fuel is provided before the next honeycomb catalyst and the process continues until the last honeycomb catalyst where the last fuel and oxidant react.

As shown in fig. 4, the inner flow channel 403 is provided for oxidant flow, as indicated by axial arrows 420. One or more fuel lines 452 extend down the combustor 400 within the outer flow passage 405 or the inner flow passage 403. A fuel line 452 supplies fuel to the heater and terminates in one or more fuel injectors 454 that inject fuel into the oxidant in the inner flow passage 403. In one embodiment, there is one fuel line with many fuel injectors, while in another embodiment there is a bundle of fuel lines, each terminating with a fuel injector. The plurality of fuel lines 452 may be symmetrically or asymmetrically disposed about the inner flow channel 403.

The flow barrier (flow barrier)410 of the fig. 4 embodiment is not permeable, as in fig. 3, and does not extend all the way to the heater closed end 404. Additionally, a number of honeycomb catalysts 455 allow fuel and oxidant to flow to the heater closed end 404. The fuel and oxidant are mixed just prior to each honeycomb catalyst, and the reaction between the fuel and oxidant occurs within each honeycomb catalyst. The flue gas flows from the heater closed end 404 to the gas inlet/outlet portion 406 through the outer flow channel 405.

In one embodiment, refractory material is used near the fuel injection point to protect the heater from overheating and corrosion. Thus, in one embodiment, the fuel injector is ceramic. In another embodiment, a ceramic lining is provided to the metal surface where the fuel and oxidant react or may react, such as near each fuel injector.

In various embodiments, air, oxygen-enriched air, or pure oxygen is provided through the internal flow channel 403. Natural gas or other fuel is provided by a plurality of fuel injectors 454 (one for each honeycomb catalyst) where the fuel is metered, injected, and mixed with the gas in the inner flow channel 403. Thus, for example and without limitation, downstream of each fuel injection nozzle 454 is an oxidation catalyst bed 455 in which the injected fuel gas is oxidized by the O present in the oxidant line₂And (4) completely oxidizing. The oxidant concentration decreases as the oxidant flows through the heater. In one embodiment, sufficient oxidant is provided to consume all of the fuel at the last honeycomb catalyst.

The catalytic bed of this embodiment may be of standard "honeycomb" design, such as those used in automotive applications. Such honeycomb catalysts operate at Gas velocities of about 1-2 m/s (to make mass transfer from bulk Gas to the flow barrier 410 possible in reasonable channel lengths). The use of pure oxygen is thus advantageous for minimizing the heater size. To facilitate mixing, it is preferred to position the fuel injection nozzle 454 immediately after each catalyst bed 455 so that the subsequent pipe section provides heat transfer and mixing of the fuel into the bulk gas. Efficient mixing is desirable because low gas velocities can cause mixing efficiency problems, potentially leading to so-called hot spots in the catalyst.

In one embodiment, the catalytic bed comprises an active metal supported by a porous ceramic catalytic material. In another embodiment, the catalytic bed 455 is the inner surface of a porous metal frit. In yet another embodiment, the catalytic bed 455 is an active metal supported by a porous metal frit or mesh. In another embodiment, the catalytic bed 455 is comprised of porous beads, pellets, or extrudates that support the active metal.

Fig. 5 shows a temperature profile resulting from a numerical simulation of the performance of a specific embodiment of the heater embodiment of fig. 4. The results of fig. 5 show the first 10 of the 20 reaction zones in which the temperature profile was repeated almost identically in each zone. In this embodiment, 0.8kg/s of pure oxygen is supplied to the inner flow channel 403, CH₄The 20 fuel injectors used were distributed 30m apart over the length of the heater. Each fuel injector 454 is charged with 0.01kg/s CH₄. The total heater is thus rated at 10MW and has a length of 600m, an internal flow channel 403 of 300mm diameter and a shell diameter of 350 mm.

The internal tube temperature profile is characterized by a peak after each honeycomb catalyst bed 455 of about 800 c, which is then reduced to a temperature of about 530 c by heat transfer before reaching the next honeycomb catalyst bed 455. This simulation includes only convective heat transfer and ignores radiative heat transfer, and thus is expected to predict the actual heater temperature too high. The flue gas temperature is an almost constant temperature of 470 ℃.

As one example of a system to control heater temperature, fig. 4 shows an embodiment with an optional Temperature Sensor (TS)460 to measure the temperature of the casing along the heater. As shown, each catalyst bed 455 has an associated temperature sensor 460. The control system schematically shown in fig. 2 may be included in this or other embodiments as appropriate. Each sensor has a communication means, such as an electrical or fiber optic communication channel, to the controller 200, as shown in fig. 2. By varying the individual fuel flow rates to increase or decrease the measured temperatures, the temperature uniformity along the heater 400 can be controlled.

In an alternative embodiment, one or more of the honeycomb catalyst beds 455 of fig. 4 are replaced with high temperature burners, forming a combined catalyst bed/burner-based heater, or, in the extreme, a completely burner-based heater. Each burner fires radially toward the inner flow channel 403 without flame impingement on the surrounding steel wall. In one embodiment, a ceramic lining is provided within the inner flow channel 403 to protect that surface.

In another alternative embodiment, a low-BTU fuel gas (which contains inert components) is used as the fuel. For such fuels, it may be advantageous to reverse the operation of the heater embodiment of fig. 4 by directing the fuel down the center and separately feeding the oxidant through the various tubes feeding the reaction zone. This configuration may have the benefit that it may more accurately control the amount of heat generated in each segment.

Catalytic wall heater

Fig. 6 shows another heater embodiment, which is a catalytic wall heater 600. The heater embodiment of fig. 6 may include one or more of the elements described above, as appropriate. As with the embodiment of fig. 4, the flow barrier 610 does not extend to the heater closed end 604. Oxidant is provided through the inner flow channel 603 where it flows to the heater closed end 604 and then through the outer flow channel 605 to the gas inlet/outlet portion 606. The one or more fuel lines 652 include a plurality of fuel injectors 654 that direct fuel into the outer flow channel 605. The inner surface of the combustor casing or sleeve 608 includes a catalyst 615. The fuel and oxidant thus mix along the length of the heater 600 and react on the burner housing surface. As shown, a plurality of injection points 654 may be disposed about the circumference of the inner tube 610.

In an alternative embodiment, recycled flue gas, which is spiked (spiked) with air or oxygen, is provided through an inner flow channel 603, the inner flow channel 603 serving as an air duct to the closed end 604 of the heater. The oxidant then flows in a reverse direction in the outer flow channel 605, as opposed to in-flow. The heater housing 608 includes a catalyst covering the inner surface of the heater housing 608 forming a catalytic wall 615. Fuel injectors 654 are part of the manifold of fuel line 652 and deliver fuel to the oxidant along the length of the heater. The size and spacing of the fuel injectors 654 are such that all of the injected fuel is transferred to the catalytic wall 615 in the downstream pipe section before the next fuel nozzle by diffusion and turbulent mixing. The catalytically enhanced exothermic reaction occurs at the catalyst, where the mixture is oxygen-rich near the closed end of the heater and near stoichiometric at the other end. The wall is thus maintained at a temperature of about 500 c along the length of the heater.

In an alternative embodiment, the catalytic wall 615 moves from the outer tube to the inner tube to allow heat transfer at lower temperatures through the outer sidewall. In an alternative embodiment, the catalytic wall is outside of the inner tube 610. In a second alternative embodiment, the flow is reversed and the catalytic wall 615 is inside the inner tube 610. In this embodiment, the fuel injectors 654 may be positioned within the inner wall.

In one embodiment, the catalytic wall 615 is a series of ceramic tubes, which may be, for example and without limitation, activated alumina or alumina coated with an active metal. By installing a compressed flexible mat in place in the small gap between the alumina tube and the steel tube, the gap can be made gas tight. An alternative design for the wall catalyst is a metal "mat-type" catalytic material, which can be fixed directly to the steel surface.

This heater embodiment is itself adapted to recirculate flue gas within the heater: the low pressure drop of the inner feed pipe and the outer ring makes it possible for a standard ejector to be at the outlet of the flue gas side, so that a portion of the flue gas is sucked into the feed and thus into the inner pipe. The motive gas for the ejector is high pressure O added from a surface facility₂. This embodiment has the advantage of providing a CO only feed₂And H₂O into a smaller volume of flue gas.

This heater embodiment is also on the hotter flue gas side and the incoming air (or incorporating O)₂Recycle gas) by additional counter-current heat exchange. The heater may also be designed such that the incoming gas stream falls along the outer annulus and the exiting flue gas falls along the inner annulus.

As another example of a system for controlling the temperature of a heater, FIG. 6 shows an embodiment having a Temperature Sensor (TS)660 to measure the temperature of the casing along the heater. A temperature sensor 660 and control system, shown schematically in fig. 2, may be included in this or other embodiments as appropriate. Each sensor has a communication means, such as an electrical or fiber optic communication channel, to the controller 200, as shown in fig. 2. By varying the individual fuel flow rates to increase or decrease the measured temperatures, the temperature uniformity along the heater 600 can be controlled.

Reference in the specification to "one embodiment," "an embodiment," or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, appearances of the phrases "in one embodiment," "in an embodiment," or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments as will be apparent to those of ordinary skill in the art in view of the disclosure.

The technology of the present application is therefore described with a certain degree of particularity with respect to the exemplary embodiments. It should be noted, however, that the present technology is defined by the following claims read in light of the prior art, such that modifications or changes may be made to the example embodiments without departing from the inventive concepts contained herein.

Claims (34)

1. A heater operable on a fuel supply and an oxidant supply, the heater comprising:

an elongated housing having a closed end and comprising:

a first housing region adapted to receive fluid from the fuel supply and the oxidant supply; and

a second housing section providing an outflow path for flue gas formed by the reaction of the fuel and the oxidant; and

an elongated flow restricting medium comprising a catalytic material interposed between the first and second housing regions;

wherein fluid received from said fuel supply and said oxidant supply flows into said first housing region, permeates into said flow restricting medium along its length, and exothermically reacts with said catalytic material, and

wherein the flow restriction medium is in the form of a tube concentrically disposed within the housing and extending to the closed end to create a pressure drop across the flow restriction medium between the first housing region and the second housing region.

2. The heater of claim 1, wherein the housing has a tubular configuration.

3. The heater of claim 1, wherein the flow restricting medium has an interior defining the first housing region.

4. The heater of claim 1, wherein the flow restricting medium has an interior defining the second housing region.

5. The heater of claim 1, wherein the fluid flows laterally across the flow restricting medium in a controlled and uniform manner.

6. The heater of claim 1, wherein the heater is submersible in an oil bath, and wherein the flow rates of the fuel and oxidant supplied are such that the exothermic reaction is sufficient to heat the inner surface to maintain the oil bath at a temperature between 275 ℃ and 450 ℃.

7. The heater of claim 6, wherein the exothermic reaction is sufficient to heat the inner surface to maintain the oil sump at a temperature of approximately 350 ℃.

8. The heater of claim 6, wherein the housing temperature varies by less than 10 ℃ over a 10 meter length of the heater.

9. The heater of claim 6, wherein the housing temperature varies by less than 20 ℃ over a 10 meter length of the heater.

10. The heater of claim 6, wherein the housing temperature varies by less than 40 ℃ over the length of the heater.

11. The heater of claim 6, wherein the housing temperature varies by less than 100 ℃ over the length of the heater.

12. A heater operable on a fuel supply and an oxidant supply, the heater comprising:

an elongated housing having a closed end and comprising:

a first housing region extending along a length of the housing and adapted to receive fluid from one of the fuel supply and the oxidant supply; and

a second housing section providing an outflow path for flue gas formed by the reaction of the fuel and the oxidant;

a flow barrier disposed between the first housing region and the second housing region such that the first housing region and the second housing region are in fluid communication at the closed end; and

a plurality of catalyst beds disposed along the length of the first shell region, each of the catalyst beds having a respective reaction zone; and

at least one conduit for receiving fluid from the other of said fuel supply and said oxidant supply and providing it to each of said reaction zones;

wherein the fluids received from the fuel supply and the oxidant supply mix and undergo an exothermic reaction in each of the reaction zones.

13. The heater of claim 12, wherein the housing has a tubular configuration and the flow barrier is in the form of a tube concentrically disposed within the housing.

14. The heater of claim 13, wherein the flow barrier has an interior defining the first housing region.

15. The heater of claim 13, wherein the flow barrier has an interior defining the second housing region.

16. The heater of claim 12, wherein the heater is submersible in an oil bath, and wherein the flow rates of the fuel and oxidant supplied are such that the exothermic reaction is sufficient to heat the inner surface to maintain the oil bath at a temperature between 275 ℃ and 450 ℃.

17. The heater of claim 16, wherein the exothermic reaction is sufficient to heat the inner surface to maintain the oil sump at a temperature of approximately 350 ℃.

18. The heater of claim 16, wherein the housing temperature varies by less than 10 ℃ over a 10 meter length of the heater.

19. The heater of claim 12, wherein each said catalytic bed comprises a honeycomb material.

20. The heater of claim 12, wherein each said catalytic bed comprises an active metal carried by a porous metal frit.

21. The heater of claim 12, wherein each said catalytic bed comprises an active metal supported by a porous ceramic catalytic material.

22. The heater of claim 21 wherein the catalytic material is in a form selected from pellets, spheres, and extrudates.

23. The heater of claim 12, wherein each of the reaction zones has an associated injection nozzle connected to the at least one conduit.

24. The heater of claim 23, wherein one or more of each injection nozzle comprises a burner nozzle that facilitates mixing and reaction of the received fluid.

25. The heater of claim 23, wherein each of the injection nozzles has a nozzle size selected to offset a pressure drop along the length of the first housing region to provide an equal flow rate to each of the reaction zones.

26. The heater of claim 23, wherein flow through the at least one conduit is controlled at the surface, thereby enabling active control of the injection flow rate of the injection nozzle.

27. The heater of claim 23, wherein at least some flue gas is recirculated from the second housing region into the first housing region.

28. The heater of claim 27, wherein the flue gas is recirculated by an ejector recirculation compressor.

29. A method of providing heat for pyrolyzing a hydrocarbon formation, the method comprising:

inserting an elongated housing into the hydrocarbon formation;

injecting an oxidant and a fuel into the housing;

flowing at least one of the oxidant and the fuel through a flow restricting medium comprising a catalytic material;

reacting said fuel and said oxidant exothermically with said catalytic material; and

the injection of oxidant and fuel is controlled to maintain the oil pool around the housing at a temperature between 275 ℃ and 450 ℃.

30. The method of claim 29, comprising flowing the oxidant and the fuel through the flow restricting medium.

31. The method of claim 29, comprising evacuating flue gas from a reaction of the fuel and the oxidant in the housing.

32. The method of claim 31, comprising heating at least one of the oxidant and the fuel with the flue gas.

33. The method of claim 29, comprising flowing one of the oxidant and the fuel through a plurality of catalyst beds.

34. The method of claim 33, comprising injecting the other of the oxidant and the fuel in the vicinity of each of the catalyst beds.