10/774,298, filed on February 6,2004, entitled MICROCHANNEL COMPRESSION REACTOR, "the disclosure of which is incorporated herein by reference.

BACKGROUND [0002] The present disclosure is related to unit operations where at least a portion of the unit operation is in compression; and more particularly, to unit operations where at least a portion of the unit operation is contained within a pressure vessel and maintained in compression.

[0003] Prior art disclosures, such as U. S. Patent No. 5,167, 930, disclose a sealed chamber encasing a reactor, where the pressure within the sealed chamber equals that of the reactor. The equalization of pressures between reactor and chamber is maintained by providing an expandable reactor and an expandable sealed chamber that accommodated for such changes.

[0004] Other prior art disclosures, such as U. S. Patent No. 3,515, 520, disclose a reactor with an internal corrosion resistant sleeve adapted to receive a catalyst and/or a corrosive reactant therein. The sleeve is jacketed by a higher-pressure flow of a non-corrosive reactant to prohibit leaks in the sleeve from leaking the corrosive reactant and/or catalyst and making contact with the exterior reactor walls. The non-corrosive reactant enters the sleeve through an opening and exits via another opening in fluid communication with the catalyst/corrosive reactant and is thereafter consumed through the normal reaction process.

[0005] Still further prior art disclosures, such as U. S. Patent No. 2,462, 517, disclose a multiple walled reactor where an internal, first wall confines the reaction chamber, and a second wall defines a cavity occupied by a pressurized atmosphere, and a third wall defines a cavity occupied by a cooling fluid. The pressurized atmosphere is used to regulate the external reactor vessel pressure, while the cooling fluid is used to regulate the thermal energy within the pressurized reservoir and the reactor.

SUMMARY [0006] The present disclosure is related to unit operations where at least a portion of the unit operation is in compression; and more particularly, to unit operations where at least a portion of the unit operation is contained within a pressure vessel and maintained in compression by a compressive medium that may include, without limitation, an inert medium and a chemical reactant. The compressive nature of the medium ensures that a leak within the unit operation will result in the ingress of the medium into the unit operation and inhibit the egress of any material from the unit operation. A unit operation may include one or more of a chemical reactor, a mixer, a chemical separation unit, and a heat exchanger. A chemical separation unit may perform, without limitation, distillation, extraction, absorption, and adsorption. A further detailed embodiment makes available an inert medium generally isothermal with the unit operation to concurrently maintain compression of the unit operation and provide a sufficient source of the inert medium for purging a chemical reactor of the unit operation during a reactor shutdown procedure.

[0007] The present disclosure is also related to chemical reactors, which utilize microchannel technology, in which at least a portion of the reaction takes place within the microchannels.

More specifically, the present disclosure makes use of a chemical reactor comprising a plurality of microchannels maintained in compression from a compressive, possibly inert, medium external thereto. Even more specifically, the inert medium may provide heating or cooling of the microchannels and, when applicable, a blocking medium to inhibit reactant and/or product from exiting the chemical reactor if the integrity of the reactor has been compromised and/or to purge the reactor during a shutdown procedure.

[0008] The present invention discloses microchannel-based chemical processing unit operations at least partially contained within a pressurized vessel. The pressurized nature of the vessel acts as a pressure balance upon the microchannel process units as the pressure exerted upon the exterior of the process units approximates the pressures exerted upon the interior of the process units by the processes carried out within the microchannels.

[0009] In addition, the present invention includes microchannel process units that are removable from a pressurized vessel. An exemplary embodiment disclosed herein provides a pressurized vessel having conduits adapted to carry materials to and from the microchannel process units. In this manner, a docking structure associated with the vessel enables the process units to be removed, replaced, and/or reinstalled without requiring total or partial destruction of the pressurized vessel, the conduits, or the microchannel process units. In instances where one or more of the microchannel process units includes a microchannel reactor having catalyst retained within the microchannels, refurbishment of the catalyst can occur at a remote location from the vessel without utilizing the conduits of the vessel or requiring additional conduits to be constructed to provide access to the reactors through the vessel. In sum, the ability to remove and/or reinstall the microchannel process units from the pressure vessel simplifies the process for modifying, testing, and replacing the units prior to operation of the units within a pressurized environment, such as that provided by the vessel.

[0010] The present invention also includes an exemplary embodiment for carrying out a Fischer- Tropsch synthesis within a fixed or removable microchannel process unit housed at least partially within a pressurized vessel. Fischer-Tropsch synthesis reacts carbon monoxide and hydrogen in the presence of a catalyst to create higher molecular weight hydrocarbons. These higher molecular weight hydrocarbons provide the potential for partial solidification that might clog the microchannels of a microchannel process unit if the solids content of the streams is too great. To reduce the likelihood of a clog, the exemplary embodiment injects an elevated temperature fluid into the downstream sections of the microchannel process units to elevate the temperature of the product stream carrying the Fischer-Tropsch synthesis products to maintain a fluid flow within the microchannels. Before the elevated temperature fluid enters the microchannel process unit, a counter current heat exchanger is established between the conduit carrying the elevated temperature fluid and the conduit carrying the product of the Fischer- Tropsch synthesis so that farther downstream sections of the product conduit are contacted by higher elevated temperature fluid to ensure fluid flow. The exemplary embodiment also capitalizes upon the exothermic Fischer-Tropsch synthesis to provide steam for this or other processes within a chemical facility.

[0011] These and other aspect of the present invention will become apparent from the following disclosure. While some construe the claims to provide a summary of the present invention, it is to be understood that the summary of the invention is not limited to or by the claims, nor the explicit exemplary embodiments contained herein as a basis for making use of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS [0012] FIG. 1 is a schematic diagram of a first exemplary embodiment of the present invention; [0013] FIG. 2 is a schematic diagram of a second exemplary embodiment of the present invention; [0014] FIG. 3 is a schematic diagram of a third exemplary embodiment of the present invention; [0015] FIG. 4 is a schematic diagram of a first exemplary reaction process carried out in accordance with the present invention; [0016] FIG. 5 is a schematic diagram of a first alternate exemplary reaction process carried out in accordance with the present invention; [0017] FIG. 6 is a right side view of a first exemplary pressurized vessel in accordance with the present invention; [0018] FIG. 7 is an overhead view of the first exemplary pressurized vessel in accordance with the present invention; [0019] FIG. 8 is an end view of the first exemplary pressurized vessel in accordance with the present invention; [0020] FIG. 9 is a cross-sectional view of the first exemplary pressurized vessel in accordance with the present invention; [0021] FIG. 10 is a schematic representation of fluid flow through an exemplary segment of a microchannel module in accordance with the present invention; [0022] FIG. 11 is a schematic representation of fluid flow through an exemplary repeating unit of a microchannel module in accordance with the present invention; [0023] FIG. 12 is an elevated perspective view of a second exemplary pressurized vessel in accordance with the present invention; [0024] FIG. 13 is an overhead view of the second exemplary pressurized vessel in accordance with the present invention; [0025] FIG. 14 is a right side view of the second exemplary pressurized vessel in accordance with the present invention; [0026] FIG. 15 is a right side cut-away view of the second exemplary pressurized vessel in accordance with the present invention; [0027] FIG. 16 is a cross-sectional view of the second exemplary pressurized vessel in accordance with the present invention; [0028] FIG. 17 is an elevated perspective view of a first exemplary embodiment of the present invention; [0029] FIG. 18 is an elevated perspective view of the first exemplary embodiment with an exploded view of a microchannel process unit, flange, and gaskets.

[0030] FIG. 19 is a cross-sectional view of the first exemplary embodiment; [0031] FIG. 20 is an elevated perspective view of a first exemplary structure for use in fabricating the first exemplary embodiment; [0032] FIG. 21 is an elevated perspective view of a second exemplary structure for use in fabricating the first exemplary embodiment; [0033] FIG. 22 is an elevated perspective view of a third exemplary structure for use in fabricating the first exemplary embodiment; [0034] FIG. 23 is an elevated perspective view of a fourth exemplary structure for use in fabricating the first exemplary embodiment; [0035] FIG. 24 is an elevated perspective view of a fifth exemplary structure for use in fabricating the first exemplary embodiment; [0036] FIG. 25 is an elevated perspective view of a sixth exemplary structure for use in fabricating the first exemplary embodiment; [0037] FIG. 26 is an elevated perspective view of a seventh exemplary structure for use in fabricating the first exemplary embodiment; [0038] FIG. 27 is an elevated perspective view of an eighth exemplary structure for use in fabricating the first exemplary embodiment; [0039] FIG. 28 is an elevated perspective view of the first exemplary embodiment without the microchannel process units installed; [0040] FIG. 29 is an elevated cross sectional view of a first alternate exemplary embodiment; [0041] FIG. 30 is an elevated perspective view of a second exemplary embodiment; [0042] FIG. 31 is a right-side view of the second exemplary embodiment of FIG. 30; [0043] FIG. 32 is a frontal view of the second exemplary embodiment of FIG. 30; [0044] FIG. 33 is a right-side, cross-sectional view of the second exemplary embodiment of FIG.

30; [0045] FIG. 34 is a frontal, cross-sectional view of the second exemplary embodiment of FIG.

30; [0046] FIG. 35 is an elevated perspective view from the front of the second exemplary embodiment of FIG. 30, with the shell of the pressure vessel removed; and [0047] FIG. 36 is an elevated perspective view from the rear of the second exemplary embodiment of FIG. 30, with the shell of the pressure vessel removed.

DETAILED DESCRIPTION [0048] The exemplary embodiments of the present invention are illustrated and described below as steps, procedures, and mechanisms for carrying out desired processes. The various orientational, positional, and reference terms used to describe the elements of the invention are utilized according to such exemplary steps, procedures, and mechanisms. However, for clarity and precision, only a unitary orientational or positional reference will be utilized; and, therefore it will be understood that the positional and orientational references used to describe the elements of the exemplary embodiments of the present invention are only used to describe the elements in relation to one another. Thus, variations envisioned by one of ordinary skill shall concurrently fall within the scope of the disclosure of this invention.

[0049] Referring now to the drawings, and in particular to FIG. 1, a first exemplary system 8 includes a compressive medium supply/source 10 in selective fluid communication with an optional compressor/pump 12. The compressive medium contained within the supply/source 10 may be in the form of a gas or a liquid and may likewise include inert fluids known to those of ordinary skill in the art. In a gaseous form, the compressive medium is fed to the compressor 12 prior to filtration of the medium by a filtration unit 14 to remove impurities or particulate matter associated therewith. Those of ordinary skill are familiar with the plethora of filtration operations available and represented by the filtration unit 14. The compressive medium may be deposited within a holding tank 16 in selective fluid communication with a pressurized vessel 18 to provide a filtered and pressurized compressive medium thereto.

[0050] The pressurized vessel 18 contains a first unit operation 22 therein that is maintained in compression by the compressive medium occupying interior regions of the pressurized vessel 18 exterior to the first unit operation 22. Both the pressurized vessel 18 and the first unit operation 22 include sensors 20,24 coupled thereto operative to detect pressures within the pressurized vessel 18 and the first unit operation 22. The first unit operation 22 may include, without limitation, a chemical reactor, a mixer, a chemical separation unit, and a heat exchanger. A chemical separation unit may perform, without limitation, distillation, extraction, absorption, and adsorption. Thus, it is to be understood that a unit operation may perform one or more than one operation.

[0051] The first unit operation 22 is adapted to be in fluid communication with a material source 28 and receive material therefrom, while an output conduit carries away processed material from the first unit operation 22 and is adapted to be in fluid communication with a processed material reservoir 30. The first unit operation 22 may include one or more microchannels in exemplary configurations, such as, without limitation, as discussed in U. S. Patent No. 6,192, 596 entitled "Active microchannel fluid processing unit and method of making, "and U. S. Patent No.

6,622, 519 entitled"Process for cooling a product in a heat exchanger employing microchannels for the flow of refrigerant and product, "each of which is hereby incorporated by reference. Such microchannels may include catalytic agents such as, without limitation, in the form of an interior wall lining, in the form of packed particles, and in the form of lined or packed inserts adapted to be positioned within the microchannels. The outlet stream of the first unit operation 22 may be in fluid communication and/or thermal communication with one or more additional unit operations, in addition to or in lieu of the process material reservoir. Such an additional unit operation may be adapted to process one or more of the constituents comprising the processed material stream and such an additional unit operation may include, without limitation, a distillation unit separating one or more constituent components thereof.

[0052] A second unit operation 26 may be in thermal communication with the first unit operation 22 to allow for thermal energy to be exchanged therebetween. For instance, in an exemplary circumstance where the first unit operation 22 includes a chemical reactor carrying out endothermic reactions, the second unit operation 26 may include a heat exchanger to facilitate providing at least a portion of the thermal energy required to initiate and/or maintain the reactions within the chemical reactor of the first unit operation 22. Such an exemplary second unit operation 26 may be adapted to carry saturated steam into thermal communication with the chemical reactor of the first unit operation 22 and carry away condensed water or lower temperature steam therefrom. Various assemblies and mechanisms capable of facilitating the transfer of thermal energy between unit operations via at least one of convection, conduction, and radiation are well known to those of ordinary skill in the art.

[0053] It is likewise within the scope and spirit of the invention for the second unit operation 26 to include a chemical reactor in addition to, or in place of, the heat exchanger. An exemplary chemical reactor of the second unit operation 26 might carry out an exothermic reaction, such as a combustion reaction, providing a thermal energy source available to be transferred to the first unit operation 22 in thermal communication therewith. Likewise, the second unit operation 26 may include a heat exchanger having a high thermal energy fluid flowing therethrough, where a process parameter might require the reduction of the thermal energy content therein that may be achieved by thermal communication between such a fluid and the first unit operation 22.

Exemplary processes the first unit operation 22 may carry out where such thermal energy transfer may be advantageous include, without limitation, distillation and endothermic reactions.

[0054] It is also within the scope and spirit of the invention for the second unit operation 26 to provide a thermal energy sink in thermal communication with the first unit operation 22. The first unit operation 22, for example, may include a chemical reactor carrying out an exothermic reaction, such as a combustion reaction. Likewise, the first unit operation 22 may include a heat exchanger having a high thermal energy fluid flowing therethrough, where a process parameter might require the reduction of the thermal energy content therein that may be achieved by thermal communication between such a fluid and the second unit operation 26. In such an exemplary circumstance, the second unit operation 26 may include a chemical reactor carrying out an endothermic reaction, a heat exchanger, and/or another process unit adapted to facilitate thermal energy transfer from the first unit operation 22. Those of ordinary skill are familiar with the plethora of such processes falling within such exemplary circumstances.

[0055] The pressurized vessel 18 may include a vent valve 32 to vent a portion of the compressive medium contained therein. Exemplary instances where the vent valve 32 may be opened include excess thermal expansion of the compressive medium and shutdown of the first unit operation 22 and/or the second unit operation 26.

[0056] The pressurized vessel 18 may further include a purge stream and valve 34 in series therewith to provide selective fluid communication between the compressive medium within the pressurized vessel 18 and the first unit operation 22. In an exemplary configuration, the first unit operation 22 may include a chemical reactor incorporating microchannels and a catalytic agent.

In such a configuration, it may be advantageous to provide a generally isothermal stream of compressive medium, optionally an inert medium, during a shutdown procedure of the chemical reactor in order to avoid thermal shock to the first unit operation 22, maintain the integrity of any microchannels therein, and minimize or virtually eliminate thermal fouling of any catalytic agent therein. An exemplary source of generally isothermal compressive medium may include the compressive medium within the pressurized vessel 18. As such, compressive medium from the pressurized vessel 18 may be withdrawn to flow through the purge stream and associated valve 34, into the supply stream, and thereafter into the chemical reactor of the first unit operation 22 to dilute the reactant and reduce the number and/or frequency of reactions occurring therein.

Alternatively, or in addition to, the compressive medium of the purge stream may flow directly into the supply stream no longer carrying a significant amount of reactant therein to achieve a complete purge. Likewise, the chemical reactor of the first unit operation 22 may include an inlet within the pressurized vessel 18 where compressive medium may directly and selectively enter therein without utilizing the supply stream. The above exemplary purge processes may also be applicable where process units other than a chemical reactor of the first unit operation 22 are included therewith or in place thereof.

[0057] A controller 36 may be operatively coupled to the first sensor 20, the second sensor 24, the vent valve 32, and the valve 34 of the purge stream. The first sensor 20 and the second sensor 24 concurrently detect the respective pressures within the pressurized vessel 18 and the first unit operation 22 and transmit such pressure data to the controller 36. In an exemplary circumstance, it may be advantageous to maintain a higher pressure within the pressurized vessel 18 and a comparatively lower pressure within the first unit operation 22; i. e. , a circumstance where the first unit operation 22 is in compression. Upon receiving data from the first sensor 20 and the second sensor 24, a number of actions may be taken by the controller 36 to manipulate such pressures as will be apparent to those of ordinary skill in the relevant art.

[0058] It is also within the scope of the present invention to provide more unit operations other than solely the first and second unit operations discussed above. Likewise, it is within the scope of the present invention to provide more than one unit operation within the pressurized vessel, and/or provide more than one unit operation outside of the pressurized vessel that may be in thermal communication therewith. The above discussion is equally applicable to alternate embodiments having more than two unit operations, where more than one unit operation is located within the pressurized vessel or outside thereof. Such alternate embodiments will be obvious to one of ordinary skill after fully appreciating the foregoing.

[0059] In an exemplary unit operation startup procedure in accordance with the present invention, the first unit operation 22 may include a chemical reactor in fluid communication with the material source 28. A supply stream coming from the material source 28 may be ramped-up, in concentration and/or in volumetric flow, resulting in more and more material molecules flowing therethrough. Presuming that the chemical reactor of the first unit operation 22 is carrying out a reaction where, on a mole-by-mole basis, a net increase in molecules results from converting reactant (material) to product (processed material), the pressure within the chemical reactor of the first unit operation 22 may increase as more reactant is converted to product, and may also increase from increases in pressure and temperature associated with the inlet stream.

The second sensor 24 conveys pressure data to the controller 36 representing any such variance in pressure within the chemical reactor. If the comparative pressure data from the first sensor 20 and second sensor 24 indicate that the pressure within the pressurized vessel 18 is not adequate to maintain the first unit operation 22 in compression within a predetermined tolerance, the controller 36 might direct a valve (not shown) to be opened between the holding tank 16 and the pressurized vessel 18. Compressive medium maintained within the holding tank 16 at a comparatively higher pressure would rush into the pressurized vessel 18 and the resulting increase in pressure would be indicative of pressure data generated by the first sensor 20 and conveyed to the controller 36. The controller 36 would instruct the valve between the pressurized vessel 18 and the holding tank 16 to be closed after the pressure within the pressurized vessel 18 was within a predetermined tolerance of parameters associated with the startup process. This cycle may continue up to, and including, steady state operation if a pressure deficiency is observed by the controller 36.

[0060] In an exemplary unit operation shutdown procedure in accordance with the present invention, the first unit operation 22 may include a chemical reactor in fluid communication with the material source 28. The supply stream coming from the material source 28 may be constrained to limit the number of material molecules reaching the first unit operation 22. This constraint may result in the generation of fewer and fewer processed material molecules, presuming the reaction conversion rate remains relatively unchanged. Presuming that the chemical reactor of the first unit operation 22 is carrying out a chemical reaction which, on a mole-by-mole basis, results in a net increase in molecules when reactant (material) is converted to product (processed material), the pressure within the chemical reactor may decrease.

Likewise, the pressure and/or temperature of the supply stream may be decreased to decrease the pressure within the chemical reactor of the first unit operation 22. The second sensor 24 conveys pressure data to the controller 36 representative of any variance in pressure within the chemical reactor of the first unit operation 22. If the comparative pressure data from the first sensor 20 and the second sensor 24 indicate that the pressure within the pressurized vessel 18 is higher than a predetermined tolerance, the controller 36 might direct the vent valve 32 to be opened to vent at least a portion of the compressive medium within the pressurized vessel 18, thereby reducing the pressure therein. Compressive medium would exit the higher pressure pressurized vessel 18 until the controller 36 received data from the first sensor 20 indicating that the pressure within the pressurized vessel 18 was within a predetermined tolerance for shutdown and resulting in the vent valve 32 directed closed by the controller 36. Alternatively, in circumstances where the atmospheric pressure is greater than the pressure within the pressurized vessel 18, a compressor or pump (not shown) may be provided in fluid communication therewith to reduce the internal pressure within the pressurized vessel 18.

[0061] In the exemplary shutdown procedure discussed above, it may also be advantageous to concurrently purge the chemical reactor of the first unit operation 22 with the compressive medium contained within the pressurized vessel 18. The compressive medium within the pressurized vessel 18 may provide a source of compressive medium that may be relatively isothermal with the chemical reactor of the first unit operation 22 and the contents associated therewith. As the purge valve 34 is directed open by the controller 36 during an exemplary shutdown procedure, compressive medium (optionally inert medium) leaves the higher pressure pressurized vessel 18 and enters the reactant stream, thereafter entering the chemical reactor of the first unit operation 22. As discussed above, the first unit operation 22 may include a direct inlet system (not shown) for allowing compressive medium from the pressurized vessel 18 to flow directly into the first unit operation 22 without use of the supply conduit carrying the reactant stream. The purging of the chemical reactor of the first unit operation 22 with the compressive medium is intended to decrease the number of reactions occurring therein, and in an exothermic reaction cycle, will concurrently act to reduce the temperature of the chemical reactor, presuming that the reactant and/or purge entering the reactor is not at an elevated temperature. As compressive medium leaves the pressurized vessel 18, the first sensor 20 detects the drop in internal pressure and relays this data to the controller 36. The controller 36 may respond to such data by opening the valve between the holding tank 16 and the pressurized vessel 18 to allow more compressive medium to flow into the pressurized vessel, presuming that the pressure differential between the pressurized vessel 18 and the reactor 22 is outside of a predetermined tolerance. The compressive medium flowing into the pressurized vessel 18, from the holding tank 16, may be above, at, or below the temperature of the chemical reactor of the first unit operation 22 and any other contents of the pressurized vessel 18.

[0062] One of ordinary skill in the art will readily realize that the present invention does not require the first unit operation 22 to unilaterally withstand high internal pressures exhibited therein. The pressure of the compressive medium, that may optionally include an inert medium, provides a compressive force acting upon the first unit operation 22, thereby providing a counteracting force to any internal pressure developed therein. In sum, components of the first unit operation 22 may be constructed from materials having dimensions not possible but for the pressurized vessel 18 and the counteracting external pressure force acting upon the first unit operation 22.

[0063] Referring to FIG. 2, a second exemplary system 8'in accordance with the present invention includes a first unit operation 22'and a second unit operation 26'within the pressurized vessel 18'. As discussed above, the first unit operation 22'and the second unit operation 26'may include, without limitation, a chemical reactor, a mixer, a chemical separation unit, and a heat exchanger. Likewise, the first unit operation 22'and the second unit operation 26'may include microchannels and be adapted to be maintained in compression by the compressive medium within the pressurized vessel 18'. Discussion of exemplary processes that may be carried out within the first unit operation 22 of the first exemplary system 8 are equally applicable for the first unit operation 22'and the second unit operation 26'of the second exemplary system 8'. In addition, the second unit operation 26'may include a sensor 38 for detecting pressure within the second unit operation 26'and relaying such information to the controller 36'operatively coupled thereto.

[0064] Referencing FIG. 3, a third exemplary system 8"in accordance with the present invention includes a compressive medium supply/source 10"in fluid communication with a compressor 12"outputting the compressed medium to a filtration unit 14". After filtration, the compressed medium may be deposited into a holding tank 16"in fluid communication with a pressurized vessel 18"having a first sensor 20"to monitor the pressure therein. The pressurized vessel 18" contains a first unit operation 22"having a sensor 24"monitoring the pressure therein. A supply stream directs materials from a material source 28"into the first unit operation 22"and an output stream carries processed materials from the first unit operation 22"and to a processed material reservoir 30". The pressurized vessel 18"may also contain a second unit operation 26", with a sensor 38", that may be coupled to and/or in thermal communication with the first unit operation 22". The pressurized vessel 18"may also include a vent valve 32"to selectively vent compressive medium therefrom.

[0065] The first unit operation 22"and the second unit operation 26"may include one or more microchannels therein. Such microchannels, as discussed above, may include a catalytic agent in fluid communication with some or all of the supply stream such as in the form of a catalytic lining occupying at least a portion of the internal walls of the microchannels in exemplary configurations where the first unit operation 22"and/or the second unit operation 26"include a chemical reactor.

[0066] As discussed previously with respect to the first and second exemplary embodiments 8, 8', the first unit operation 22"and the second unit operation 26"may include, without limitation, a chemical reactor, a mixer, a chemical separation unit, and a heat exchanger. A chemical separation unit may perform, without limitation, distillation, extraction, absorption, and adsorption. As discussed in more detail in the first exemplary embodiment 8, the first unit operation 22"may include a chemical reactor in thermal communication with a chemical reactor of the second unit operation 26". Exemplary shutdown, steady state, and start-up procedures as discussed previously are applicable to the third exemplary embodiment 8", as the pressurized vessel 18"may include a valve (not shown) to provide selective fluid communication between the compressive medium contained therein and the first unit operation 22"and/or the second unit operation 26"to encompass the exemplary purposes discussed above, such as purging, and other purposes apparent to those of ordinary skill. A near isothermal purge fluid, such as the compressive medium within the pressurized vessel 18", may avoid potential equipment damage due to thermally induced stresses otherwise associated with large temperature differences between the purge fluid and the components of the first unit operation 22"and/or the second unit operation 26".

[0067] The third exemplary embodiment 8"also includes a recycle stream having a recycle valve 39 in series therewith to provide selective fluid communication between the pressurized vessel 18"and at least one of an auxiliary heat exchanger 40 and the compressive medium source 10".

The auxiliary heat exchanger 40 may be utilized to vary the thermal energy associated with the compressive medium cycled therethrough before being directed to the compressive medium supply/source 10".

[0068] It is also within the scope and spirit of the present invention to concurrently provide heat transfer from or to the first unit operation 22"and/or the second unit operation 26"via the compressive medium. In such an exemplary procedure it is anticipated that the compressive medium within the pressurized vessel 18"and within the system is sufficient in and of itself to handle the heat loads of the first unit operation 22"without requiring the second unit operation 26"to bear any of the heat load, and vice versa. It is likewise within the spirit of the present invention to enable one unit operation 22", 26"to bear the entire heat load without necessitating the compressive medium within the recycle stream and system to bear a significant duty of the heat load of the alternate unit operation 26", 22". In an exemplary procedure where the first unit operation 22"requires thermal energy added thereto or taken away therefrom, it may be desirable for the second unit operation 26"to be capable of accommodating the entire heat load, and likewise providing the compressive medium and the system associated therewith to be capable of accommodating the entire heat load, such that the complete failure of either the compressive medium and system or a unit operation 26"would allow the other to fully accommodate the thermal energy duty associated with the first unit operation 22", and vice versa.

[0069l Referring to FIG. 4, a first exemplary reaction process 100 may be carried out using components described in the first, second, or third exemplary embodiments 8,8', 8", and obvious variations thereof. However, for purposes of simplicity, not all components analogous to the exemplary components of the first, second, or third exemplary embodiments 8, 8', 8"are shown and/or discussed. A pressurized vessel 18"'contains a compressive medium compressing a first unit operation 22"'adjacent to a second unit operation 26"'. The first unit operation 22"'includes a first chemical reactor carrying out an exothermic reaction process, such as, without limitation, a combustion reaction process. Those of ordinary skill are familiar with such a process and the conditions under which it may be carried out. The second unit operation 26"'includes a second chemical reactor that carries out an endothermic reaction therein, such as, without limitation, steam reformation, in thermal communication with the first chemical reactor.

[0070] The first chemical reactor includes microchannels in fluid communication with fuel from a fuel source 102 and oxygen from an oxygen source 104. The microchannels of the first chemical reactor may include catalyst that facilitates the combustion reaction between the fuel and oxygen to result in at least one product and the generation of thermal energy. After combustion, the exhaust/product flows from the first chemical reactor and may be released to the open atmosphere and/or be collected in an exhaust/product reservoir 106.

[0071] The second chemical reactor includes microchannels in fluid communication with steam from a steam feed 108 and hydrocarbons from a hydrocarbon source 110. (See U. S. Patent No.

6, 680, 044, which is hereby incorporated by reference. ) The microchannels of the second chemical reactor may include catalyst that facilitates an endothermic reformation reaction between the steam and hydrocarbons and results in at least one product. After the reaction, the product flows from the second chemical reactor and is directed to a product reservoir 112. It is envisioned that the product reservoir 112 may provide a feed source for one or more downstream unit operations.

[0072] The oxygen, fuel, steam and hydrocarbons may travel in a cross current, counter current or co-current direction with respect to the exhaust/product to facilitate thermal energy transfer therebetween. The enhanced heat transfer capabilities offered by microchannels allow thermal energy generated by the combustion reaction to be efficiently transferred to the oxygen, fuel, steam and hydrocarbons flowing therethrough.

[0073] The compressive medium within the pressurized vessel 18"'may include high pressure water that is heated by the thermal energy generated from the combustion reaction within the first chemical reactor. A fraction of the high pressure water may be withdrawn from the pressurized vessel 18"'and directed through a recycle conduit 114 where it is flashed into a steam drum 116. The pressure inside the steam drum 116 is considerably less than that within the pressurized vessel 18"'and the recycle conduit 114 which enables a portion of the high temperature high pressure water to change phase and generate saturated steam. The bottoms product, liquid water, is fed to a compressor/pump 118 and cycled back to the pressurized vessel 18"'to absorb thermal energy from the first chemical reactor. The tops product, or steam, is fed to the steam feed 108 that provides steam as a reactant for the steam reformation reaction carried out within the second chemical reactor. Those of ordinary skill are familiar with the various processes that may likewise make use of the steam generated by the first exemplary reaction process 100.

[0074] Referring to FIG. 5, an alternate first exemplary reaction process 100""may be carried out using some of the components described in the first reaction process 100, and obvious variations thereof. The reaction process 100""includes an exothermic reaction within the first unit operation 22""and an endothermic reaction within the second unit operation 26"". The alternate first exemplary reaction process 100""includes a water source 117 in fluid communication with the compressor/pump 118""to provide a source of pressurized water to the pressurized vessel 118"". Those of ordinary skill will understand that a water source is implicit in the first exemplary reaction process 100 discussed previously. Vapor is generated from the water contained in 118""by the excess heat generated by 22"". A steam drum/separator 119 in fluid communication with the pressurized vessel 118""contains both water and steam, and provides a source of steam to the steam feed 108""and second unit operation 26"". The steam and water are separated within the drum 119 prior to the steam being directed to the stream feed 108"".

[0075] The reactants and products discussed herein may include fluids, such as, without limitation, gases, liquids, and mixtures thereof that may contain solids. Although the above discussion refers to streams, conduits, and channels, it is to be understood that such process paths may be comprised of a plurality of streams, conduits, and channels. For example, tens, hundreds, thousands, tens of thousands, hundreds of thousands, or millions of separate process paths operating concurrently may be employed with the present invention. For example, a process stream may be comprised of a plurality of individual microchannels that accommodate a requisite volumetric flow, with such microchannels being provided in multiples as needed to accommodate such flow.

[0076] Referencing FIGS. 6-9, a first exemplary pressurized vessel unit 120 includes a long cylindrical pressurized vessel 18,18', 18", 18"', 18"" (collectively 18*) that contains a first unit operation 22,22', 22", 22"', 22"" (collectively 22*) and a second unit operation 26,26', 26", 26"', 26"" (collectively 26*) of the exemplary embodiments 8,8', 8", 8"', 8""discussed above, where the first unit operation 22* and the second unit operation 26* are combined to form an integrated module 122.

[0077] Referencing FIG. 10, an exemplary segment of a module 122 includes a repeating unit 124 that may comprise a series of adjacent microchannels. For purposes of explanation only, the first unit operation 22* and the second unit operation 26* each include a chemical reactor. The first unit operation 22* may include a first microchannel 126 adapted to carry a processed material (product) therein, where the processed material may be the resultant of an endothermic reaction, for example. The first unit operation 22* may also include a second microchannel 128 adapted to carry a material (reactant) therein, isolated adjacently in the repeating unit 124 from, but in fluid communication with, the first microchannel 126. The second unit operation 26* may include a third microchannel 130 that may be adapted to carry a reactant (fuel) therein. The second unit operation 26* may also include a fourth microchannel 132 that may be adapted to carry a reactant (air) therein and be in fluid communication with the third microchannel 130 to selectively mix the reactants in a catalytic portion of the third microchannel 130 where a reaction is carried out to convert the reactants to product. The second unit operation 26* may further include a fifth microchannel 134 that may be adapted to carry a flow of products, isolated adjacently in the repeating unit 124 from, but in fluid communication with, the third and fourth microchannels 130,132. Whereas, the first and second microchannels 126,128 are adapted to be separate from, and not in fluid communication with, the third, fourth, and fifth microchannels 130,132, 134.

[0078] Referring to FIG. 11, the repeating unit 124 may be combined with a second repeating unit 124 to create a basic unit 136 that is repeated throughout the module 122. Reference is had to U. S. Patent No. 6,622, 515 entitled"Process for Cooling a Product in a Heat Exchanger Employing Microchannels for the Flow of Refrigerant and Product, "U. S. Patent Application Serial No. 10/222,196 entitled"Integrated Combustion Reactors and Methods of Conducting Simultaneous Endothermic And Exothermic Reaction, "U. S. Patent Application Serial No.

10/222,604 entitled"Multi-Stream Microchannel Device, "U. S. Patent Application Serial No.

10/219,956 entitled"Process for Conducting an Equilibrium Limited Chemical Reaction in a Single Stage Process Channel, "and U. S. Patent Application Serial No. 10/306,722 entitled "Microchannel Apparatus, Methods of Making Microchannel Apparatus, and Processes of Conducting Unit Operations, "for a more detailed explanation of the construction of the module 122, and each disclosure is hereby incorporated by reference.

[0079] Referencing FIGS. 6-9, the pressurized vessel unit 120 includes a throughput 140 adapted to receive a supply stream in fluid communication with a material source (not shown), a throughput 142 adapted to receive an output stream in fluid communication with a processed material reservoir (not shown), and a throughput 144 adapted to receive a compressive medium stream in fluid communication with a compressive medium source (not shown). Two headers 146,148 are mounted to the pressurized vessel unit 120 and include openings 150,152 therein that are adapted to be in fluid communication with a second material source (not shown), such as a methane holding tank, and third material source (not shown), such as an air tank. The exemplary unit 120 includes five microchannel modules 122 located at least partially therein, with each of the first unit operations 22* in fluid communication with the others 22*, to the exclusion of the second unit operations 26*, and with each of the second unit operations 26* in fluid communication with the others 26*.

[0080] Referring to FIGS. 8 and 9, a module 122 is at least partially contained within the pressurized vessel unit 120, such that the first unit operation 22* and the second unit operation 26* are adapted to be in compression. A conduit 154 in fluid communication with the header 146 may provide a supply stream to the second unit operation 26*, while a conduit 156 in fluid communication with the header 148 may likewise carry a supply stream to the second unit operation 26*. An internal conduit 158 in fluid communication with the throughput 140 (See FIG. 8) may provide a material, such as a reactant, to the first unit operation 22*, while an internal conduit 159 in fluid communication with a throughput 142 (See FIG. 8) may carry away processed material, such as a product, from the first unit operation 22*. In an exemplary combustion reaction occurring within the second unit operation 26*, the conduit 154 may carry a hydrocarbon and the other conduit 156 may carry oxygen, air, or another oxygen source. The exhaust or product stream from the second unit operation 26* may be vented through a port 160 approximate the exposed portion of the module 122. It is also within the scope and spirit of the present invention to capture the exhaust/product by placing a manifold over the port 160 and directing the exhaust/product to a subsequent process unit (not shown).

[0081] The pressurized vessel unit 120 may also include two or more refurbishment lines 162, 164 for catalyst regeneration within the unit operations 22*, 26*. Optionally, the pressurized vessel unit 120 may include flanged conduits 166 to be utilized as inspection ports for the unit operations 22*, 26* contained therein. Such flanged conduits 166 would typically be flanged closed under normal operation of the pressurized vessel unit 120 and unit operations 22*, 26* contained therein.

[0082] Referencing FIGS. 11-15, a second exemplary pressurized vessel unit 200 includes a long cylindrical pressurized vessel 18* that houses the first unit operation 22* and the second unit operation 26* therein under a compressive force supplied by a compressive medium also housed therein and entering via an opening 201. As discussed with respect to the first exemplary pressurized vessel unit 120, the first unit operation 22*, and the second unit operation 26* may each include a microchannel chemical reactor for purposes of explanation only.

[0083] The unit 200 is sealed at both longitudinal ends 202,204 with respect to an external environment and may include five microchannel modules 122', at least partially housed therein, in selective fluid communication with headers 206, 208, 210, 212 mounted exteriorly thereto. A first header 206 includes a supply stream inlet 214 in fluid communication with a reactor of the first unit operation 22*, while a second header 208 includes an output stream outlet 216 also in fluid communication with the first unit operation 22*. A third header 210 includes a supply stream inlet 218 in fluid communication with a reactor of the second unit operation 26*, and a fourth header 212 includes a supply stream inlet 220 in fluid communication with the second unit operation 26*. As discussed above, each module 122'may comprise a first unit operation and a second unit operation including microchannels therein, and thus, the headers 206,208, 210,212 provide fluid communication with the respective modules 122.

[0084] In an exemplary steam reformation reaction carried out within the first unit operation 22*, the first header 206 may carry steam and methane (material) and the second header 208 may carry hydrogen, carbon dioxide, and carbon monoxide (processed material). In an exemplary combustion reaction within the second unit operation 26*, the third header 208 may carry a hydrocarbon (reactant or fuel) and the fourth header 210 may carry air or another oxygen source (reactant). The exhaust or product stream from the second unit operation 26* may be vented through a port 230 approximate the exposed portion of the module 122'. It is also within the scope of the present invention to capture the exhaust/product by placing a manifold over the port 230 and direct the exhaust/product to a subsequent process unit (not shown).

[0085] The pressurized vessel unit 200 may also include two or more refurbishment lines 222, 224 (not shown in FIGS. 12 and 13) for catalyst regeneration within the reactors of the unit operations 22*, 26*. Optionally, the pressurized vessel unit 200 may include flanged conduits (not shown) to be utilized as inspection ports for the unit operations 22*, 26*. Such flanged conduits would typically be flanged closed under normal operation of the pressurized vessel unit 200.

[0086] As will be understood by one skilled in the art, the exemplary pressurized vessel units 120,200 shown in FIGS. 6-9 and 12-16 are wholly exemplary in nature and may be further configured to include features discussed in any of the exemplary embodiments above.

[0087] The present invention has been described above with respect to exothermic and endothermic reactions in general, and combustion and reformation reactions as more specific examples, however, the present invention is applicable for carrying out other reactions, such as, without limitation, acetylation, addition reactions, alkylation, dealkylation, hydrodealkylation, reductive alkylation, amination, ammoxidation aromatization, arylation, autothermal reforming, carbonylation, decarbonylation, reductive carbonylation, carboxylation, reductive carboxylation, reductive coupling, condensation, cracking, hydrocracking, cyclization, cyclooligomerization, dehalogenation, dehydrogenation, oxydehydrogenation, dimerization, epoxidation, esterification, exchange, Fischer-Tropsch, halogenation, hydrohalogenation, homologation, hydration, dehydration, hydrogenation, dehydrogenation, hydrocarboxylation, hydroformylation, hydrogenolysis, hydrometallation, hydrosilation, hydrolysis, hydrotreating (including hydrodesulferization HDS/HDN), isomerization, methylation, demethylation, metathesis, nitration, oxidation, partial oxidation, polymerization, reduction, reformation, reverse water gas shift, Sabatier, sulfonation, telomerization, transesterification, trimerization, and water gas shift.

[0088] For each of the exemplary reactions listed above, there are catalysts and conditions known to those skilled in the art for carrying out such reactions that likewise fall within the scope and spirit of the present invention. For example, the invention contemplates methods of amination through an amination catalyst and apparatuses containing the amination catalyst. In sum, the invention can be described for each of the reactions listed above, either individually (e. g. , hydrogenolysis), or in groups (e. g. , hydrohalogenation, hydrometallation and hydrosilation with hydrohalogenation, hydrometallation and hydrosilation catalyst, respectively).

[0089] Referring to FIGS. 17-19, a third exemplary embodiment of the present invention includes a microchannel unit operation assembly 1000. The microchannel unit operation assembly 1000 includes a cylindrical pressurized vessel 1200 that defines an interior cavity bounded by a cylindrical wall 1400 and two end caps 1600, 1800. An entrance orifice and an exit orifice (not shown) through the rear end cap 1600 provide access to the interior cavity and are operative to supply or remove a pressurized fluid housed within the vessel 1200. A dock 2000 is mounted to the top of the vessel 1200 and runs the majority of the longitudinal length of the vessel 1200. The dock 2000 circumscribes a rectangular opening 2200 within the cylindrical wall 1400 and defines five generally rectangular openings 2400 that are operative to receive five removable microchannel process units 2600. As will be discussed in more detail below, the microchannel process units 2600 include at least one side that is tapered and adapted to rest upon a correspondingly tapered surface of the dock 2000. Thereafter, a rectangular flange 2800 bolts to the dock 2000 (and optionally to the unit 2600) and is operative to sandwich a gasket assembly 3000,3000'between each process unit 2600 and the dock 2000. The first gasket assembly 3000 is operative to seal the rectangular opening in the dock 2000 occupied by the microchannel process units 2600 and seal an interface between the flange 2800 and each process unit 2600, while the second gasket assembly 3000'is operative to seal the interface between the openings within the process unit 2600 and the openings on the side of the dock 2000.

[0090] A series of conduits 3200,3400, 3600,3800 are mounted to the vessel 1200 and are adapted to direct fluid streams into, or away from, each of the microchannel process units 2600.

Each microchannel process unit 2600 includes a series of microchannels adapted to be in fluid communication with the conduits mounted to the vessel 1200. Three of the conduits 3200,3400, 3600 are operative to carry input streams, while one conduit 3800 carries an output stream. A second output stream is exhausted at the top of each microchannel process unit 2600 through the rectangular opening 4000 in the flange 2800 and gasket assembly 3000.

[0091] For purposes of explanation only, the microchannel process unit 2600 includes a microchannel reactor 2600 operative to carry out two concurrent reactions. While various reactions may be carried out within a microchannel reactor 2600, for purposes of explanation, it is presumed that the microchannel reactor 2600 will carry out a combustion reaction and a syngas reaction (where methane and stream are reacted to generate primarily carbon monoxide and hydrogen gas). In such an exemplary combustion reaction, a fluid fuel stream, which may consist of carbon dioxide, hydrogen, methane, and carbon monoxide, is carried through the first input conduit 3200 and directed to a first set of microchannels within the reactor 2600. The second input conduit 3400 is operative to carry an oxygen-rich fluid, which may consist of air, that is directed to a second set of microchannels within the reactor 2600. The second set of microchannels is operative to direct the oxygen-rich fluid into direct contact with the fuel stream flowing within a downstream section of the first set of microchannels. This downstream section includes distributed catalyst that facilitates a combustion reaction between the oxygen-rich fluid and the fuel stream generating thermal energy and reaction products. The catalyst may line the walls of the downstream section of the first set of microchannels or be retained within the microchannels in another manner.

[0092] The downstream section of the first set of microchannels is in intimate contact with a third set of microchannels containing a reactant stream delivered thereto by the third input conduit 3600. The reactant stream includes a pressurized mixture of steam and methane that utilize the thermal energy generated by the combustion reaction, in the presence of a catalyst, to drive an endothermic syngas (steam reformation) reaction where the product stream is rich in hydrogen gas. The exhaust of the combustion reaction is vented through openings 4000 within the top of the reactor 2600, while the steam reformation products are directed out of the reactor 2600 and into the first output stream 3800 for further processing downstream. Exemplary pressures exerted upon the microchannels of the reactor for these reactions include pressures at or above 335 psig. In order to reduce the stress upon the microchannels, the reactors 2600 are at least partially surrounded by a pressurized fluid within the vessel 1200 operative to provide a pressure balance by exerting a pressure of approximately 335 psig. In order to exert such pressures upon the exterior of the reactors 2600, the pressurized vessel 1200 must be fabricated to withstand these pressures for extended periods. The following is an exemplary sequence to fabricate the pressurized vessel 1200 and associated conduits 3200,3400, 3600,3800 in accordance with the present invention, based upon a cylindrical vessel 1200 having a diameter of thirty-six inches.

[0093] Referring to FIG. 20, a preliminary frame 10000 includes a rectangular metal bar 10200 having five sets of four dove-tailed rectangular openings 10400 formed therethrough that are each separated by a series of metal blocks 10600. Exemplary dimensions for the bar 10200 include 16000 inches in length, 12.15 inches in width, and 2.38 inches in thickness, while exemplary dimensions for each block 10600 include 4.00 inches in length, 12. 15 inches in width, and 7.24 inches in thickness. The metal blocks 10600 are mounted to an interior surface 10800 of the bar 10200 at a predetermined angle that, as will be discussed below, can vary between i 45 degrees from perpendicular. Each of the four rectangular openings 10400 has a dimension of 27.19 inches length, 12. 15 inches width with the depth corresponding to the thickness of the bar.

Ten sets of gasketing material 11000 are mounted to a channel (not shown) within the interior surface 10800 of the bar 10200, with each set of gasketing material 11000 surrounding two (top two 11200 or bottom two 11400) of the four dove-tailed openings 10400. Exemplary gasketing material 11000 for use with the present invention includes, without limitation, Garlock Helicoflex Spring Energized Seals, metal/graphite gaskets, reinforced graphite, corrugated metal/spiral wound gaskets, and elastomeric seals. As discussed previously, the gasketing material 11000 is operative to provide a fluidic seal between the interior surface 10800 of the bar 10200 and an exterior surface of the microchannel process unit (see FIG. 18,3000'). Two mirror image frames 10000 are constructed so that the metal blocks 10600 of each frame face one another and the exterior surfaces 11600 of each bar 10200 face away from one another.

[0094] Referencing FIGS. 21 and 22, an arcuate metal strip 11800 is welded to the exterior surface 11600 of each bar 10200. As will be apparent below, the metal strip 11800 is incorporated into the overall structure to define the cylindrical vessel 1200 (see FIG. 17) and, therefore, has an arc representative of a 9.69 inch wide longitudinal section of a thirty-six inch cylinder. The metal strip 11800 runs the entire length of the bar 10200 and is operative to divide the top two 11200 and bottom two 11400 rectangular openings 10400. A ten inch pipe segment 12000 is welded to the underneath side 12200 of the strip 11800 and welded to the exterior surface 11600 of the bar 10200 to create a longitudinal conduit 12400 supplying the bottom 11400 openings. Two arcuate extensions 12600,12800 are aligned with the ends of the metal strip 11800 and welded to respective ends of the frame 10000, which includes mounting the extensions 12600,12800 to the ends of the strip 11800, bar 10200, and block 10600. The arcuate extensions 12600,12800 are representative of a 19.65 inch segment of a thirty-six inch diameter cylinder, with the first extension 12600 having a width Wl of 20.00 inches, and the second extension 12800 having a width W2 of 6.00 inches.

[0095] Referencing FIG. 23, a ten inch pipe segment 14000 is welded to the exterior 11600 of the bar 10200, the strip 11800, the block 10600, and the extensions 12600,12800 to provide a separate longitudinal conduit 14200 feeding the top 11200 series of openings. This conduit 14200 runs in parallel with the conduit 12400 feeding the bottom two 11400 series of openings.

A notch is cut from the segment 14000 prior to welding in order to allow the front aspect 14300 to match the contours of the ends of the bar 10200, the block 10600, and top surface of the first extension 12600.

[0096] Referencing FIGS. 24 and 25, end caps 14400,14600 contacting the ends of the two respective segments 12000,14000, the bar 10200, and the far block 10600 are welded above and below the second extension 12800 in order to enclose the ends of the conduits 12400,14200.

[0097] Referring to FIG. 26, an opposing end 14800 of the first conduit 12400 receives an adapter 15000 operative to redirect the flow of materials in a direction other than along the linear longitudinal length of the bar 10200. The adapter 15000 comprises a ten inch pipe segment 15200 and an end cap 15400 contoured to match the arc of the underside of the first extension 12600. A six inch pipe segment 15600 is circumferentially welded to an orifice (not shown) in the ten inch pipe segment 15200 to provide a down tube. The resulting structure comprises an intermediate frame 16000.

[0098] Referencing FIG. 27, the two, mirror image intermediate frames 16000 are joined by welding a series of block spacers 16200 between opposing blocks 10600, resulting in five rectangular openings 16400 within the top of the eventual vessel 1200 (see FIG. 28). A corresponding spacer 16600,16800 is welded between the extensions 12600,12800 and to the block spacers 16200 and opposing blocks 10600 in order to bridge the gap between the extensions. An elbow pipe 17000 is welded to the circumferential opening of each adapter 15000, where the elbow pipe has an extension pipe 17200 welded thereto.

[0099] Referring to FIG. 28, a semicircular pipe 17200 is welded to the opposing ends 17400 of each strip 11800 and extensions 12600,12800 to provide a continuous cylindrical body 17600 (outside of the openings 15400). A rear end cap 18000 and a front end cap 18200 are welded to the cylindrical body 17600 to enclose the 3600 inch diameter opening on each end. The rear end cap 18000 includes two flanged pipes (not shown) providing fluid communication with the interior of the vessel 1200. The front end cap 18200 includes two orifices 18400 adapted to allow the pair of extension pipes 17200 to pass therethrough as the cap is oriented to abut the opening at the front of the cylindrical body 17600. A first circumferential weld mounts the body 17600 to the rear cap 18000, and a second circumferential weld mounts the front cap 18200 to the body 17600. A third set of circumferential welds is operative to close the front end of the vessel 1200 by sealing any gap between the openings 18400 and the extension pipes 17200 piercing the openings 18400. A flange 18600 is mounted to each end of the respective extension pipes 17200 and is adapted to mate with a preexisting flanged conduit (not shown). Two ten inch flanged pipes 18800 are respectively contoured to match the exterior shape of the vessel 1200 and welded to the ends of the pipe sections 14000 and to the exterior of the vessel 1200.

The flanges at the end of the pipe 18800 are adapted to mate with a preexisting flanged conduit (not shown) upon installation of the vessel 1200.

[0100] The resulting vessel 1200 is operative to provide sealed fluid communication between the flanged openings 19000,19200, 19400, 19600 and the openings 11200, 11400 along the interior sides of the vessel 1200. More specifically, the first flanged opening 19000 provides the sealed conduit 3200 (see FIG. 17) in fluid communication with the top openings 11200 longitudinally spaced along the left hand side 20000 of the vessel, whereas the second flanged opening 19200 provides the sealed conduit 3400 (see FIG. 17) in fluid communication with the top openings 11200 longitudinally spaced along the right hand side 20200 of the vessel. The third flanged opening 19400 provides the sealed conduit 3800 (see FIG. 17) in fluid communication with the bottom openings 11400 longitudinally spaced along the right hand side 20200 of the vessel, whereas the fourth flanged opening 19600 provides the sealed conduit 3600 (see FIG. 17) in fluid communication with the bottom openings 11400 longitudinally spaced along the left hand side 20000 of the vessel.

[0101] As discussed above, the orientation of the blocks 10600 with respect to the bar 10200 may be manipulated during fabrication to angle the openings 11200,11400 with respect to completely vertical, such as tapering the openings 11200,11400 inward (from bottom to top) or tapering the openings 11200,11400 outward (from bottom to top). Other methods operative to angle the openings with respect to completely vertical will become obvious to those of ordinary skill, and all such methods and apparatuses concurrently fall within the scope of the present invention. By manipulating the dimensions of the opening 16400, is it possible to suspend the microchannel process unit 2600 within the opening. For example, if each bar 10200 is oriented outward 5 degrees (from bottom to top) from vertical, a V-shaped profile is provided along at least one plane of the opening 16400 (see FIG. 19). If the microchannel process unit 2600 is correspondingly shaped to taper inward from top to bottom to match the taper of the opening 16400, it is possible to vertically suspend the reactor from the dock 2000 without requiring the process unit 2600 to be rigidly mounted to the dock, such as by welding.

[0102] Referring to FIG. 29, an alternate configuration 10000'maybe utilized in instances where the operating pressure exerted upon the process unit 2600'by the fluid within the vessel 1200' will be a positive gauge pressure, tending to push the process unit 2600'out of the opening 16400', it may be advantageous to orient each bar 10200'inward 5 degrees (from bottom to top) from vertical to provide an inverted V-shaped profile or frustropyramidal portion is provided along at least one plane of the opening 16400'so that higher pressures tend to push a process unit 2600'with a correspondingly inverted V-shaped profile more tightly against the dock 2000'. In such an instance, the process unit 2600'may include a flange 2800'or other attachment point to mount the unit 2600'to the dock/vessel 2000'/1200'. It is to be understood either approach (tapered inward or tapered outward) could be utilized in conditions calling for positive or negative operational gauge pressures to be exerted upon the process unit 2600, 2600'by the contained fluid of the vessel 1200,1200'.

[0103] Several advantages are apparent from the exemplary embodiments of the present invention. For example, by making the microchannel process unit 2600 removable from the vessel 1200, replacement of the units 2600 is made much easier, as opposed to prior methods requiring cutting the welds between the units and the vessel 1200. Welding of the units 2600 also introduced high local temperatures that tended to degrade or destroy catalyst in proximity to the weld and/or result in delaminations. In addition, by making the units 2600 removable by simply twisting a few bolts, refurbishment of catalyst within the reactor units may be accomplished without the need for separate catalyst refurbishment lines piercing the pressure vessel 1200 and units.

[0104] Other advantages of making the microchannel process units 2600 removable include the removal or replacement of individual units 2600 (as opposed to a bank of units), the ability to refurbish active metal catalysts away from the pressure vessel 1200, and the ability to pressure test or perform other tests upon the process unit 2600 away from the pressure vessel 1200.

[0105] Referencing FIGS. 30-32, a second exemplary embodiment of the present invention includes a Fischer-Tropsch reactor assembly 30000. The reactor assembly includes a pressurized vessel 30200 consisting of a hollow cylindrical shell 30400 sealed at its ends by a front end cap 30600 and a rear end cap 30800. The front end cap 30600 includes three orifices that receive three corresponding flanged conduits 31000,31200, 31400 that extend into the interior of the shell 30400. Two other flanged conduits 31600,31800 are received by two orifices within the shell 30400 and provide communication with the interior of the shell. Each end cap 30600, 30800 is mounted circumferentially to the cylindrical shell to provide a fluid tight seal therebetween. Exemplary techniques for mounting the end caps 30600,30800 to the cylindrical shell 30400 include, without limitation, welding and flanged connections utilizing torqued bolts.

Each flanged conduits 31000, 31200, 31400, 31600, 31800 is circumferentially welded to a corresponding opening within the vessel 30200 in order to mount the conduits to the vessel and ensure the vessel is capable of being pressurized and maintaining such pressure.

[0106] For purposes of explanation only, the Fischer-Tropsch reactor assembly 30000 is adapted to carry out a Fisher-Tropsch synthesis where carbon monoxide and hydrogen within a feed stream are converted into higher molecular weight hydrocarbons in the presence of a catalyst. More specifically, the higher molecular weight hydrocarbons include C5-100 paraffins, oxygenates, and olefins. In order to increase the yield of desired products, the dissipation of thermal energy away from the reactive zones of a Fischer-Tropsch reactor is important, as the reaction is highly exothermic. l01071 Referencing FIG. 33, the present invention makes use of microchannel reactors 32000 such as those disclosed in U. S. Patent No. 6,192, 596 entitled"Active microchannel fluid processing unit and method of making, "and U. S. Patent No. 6,622, 519 entitled"Process for cooling a product in a heat exchanger employing microchannels for the flow of refrigerant and product, "each of which is hereby incorporated by reference. Exemplary microchannel reactors 32000 for use with the present invention are fabricated from stainless steel alloys and include interposed microchannels, where a first set of microchannels contain catalysts utilized for Fisher- Tropsch synthesis where the reactants (CO and H2) form hydrocarbons and generate thermal energy, and a second set of microchannels carry a coolant adapted to remove at least a portion of the thermal energy generated by the Fisher-Tropsch synthesis.

[0108] Referring FIGS. 33-36, a series of microchannel reactors 32000 are housed within the interior of the vessel 30200 and receive a reactant stream with relatively high concentrations of carbon monoxide and hydrogen by way of the reactant conduit 31400. A manifold 32200 in communication with the reactant conduit 31400 is welded to each of the reactors and operative to distribute the reactant stream amongst the six microchannel reactors 32000. As the reactants flow through the microchannels (not shown), Fischer-Tropsch synthesis catalyst contained within the microchannels facilitates an exothermic reaction generating thermal energy. An internal coolant is delivered to the microchannel reactors 32000 by way of the coolant conduit 31200 feeding a manifold 32400 welded to and distributing the coolant amongst the six microchannel reactors. In this exemplary embodiment, the coolant is boiler feed water entering the reactors 32000 at approximately 220°C and exiting the reactors as a mixture of liquid water and saturated steam opposite the manifold 32400.

[01Q9] Superheated steam enters the reactors 32000 by way of the steam conduit 31000 in order to provide a flowing stream of product from the reactors 32000. As discussed above, the products from the reactors 32000 include high molecular weight hydrocarbons which may result in partial solidification within the microchannels. To inhibit the solid content of the products stream from blocking the microchannels, superheated steam is injected into the microchannels downstream from the reaction section of the microchannels to provide a source of thermal energy to the product stream and elevate the temperature within the product stream and ensure that fluid flow continues. As the product stream exits the reactors 32000 via a welded manifold 32600, the products are collected into a product conduit 32800. The product conduit 32800 is jacketed by the steam conduit 31000 and provides a countercurrent heat exchanger providing more thermal energy (higher temperature steam) to the product stream as it travels farther downstream from the reactors 32000.

10110] The vessel 30200 includes an active level control system (not shown) to inhibit the level of water within the vessel from reaching the outlets of the reactors 32000 where water and steam are exiting. An orifice (not shown) within a lower circumferential area of the vessel 30200 provides access to the water conduit 31800 for removal of water from the vessel. It is envisioned that the water withdrawn from the vessel 30200 be routed through the coolant conduit 31200 to supply the boiler feed water. At the top of the vessel 30200 is the steam outlet conduit 31600 operative to withdraw the steam produced within the reactors 32000. The active control system is also operative to maintain the fluid surrounding the reactors 32000 at an elevated pressure so that the pressure exerted upon the exterior of the reactors is not significantly less than the pressures exerted upon the interior aspects of the reactors.

[0111] Those of ordinary skill will understand that the pressure exerted by the fluids surrounding the reactors 32000 will vary depending upon the operating parameters chosen for the reactors.

Nevertheless, it is within the scope of the present invention that the vessel be constructed to withstand internal pressures of 500 psig. Exemplary materials for use in fabricating the vessel 30200 include, without limitation, SA 515, SA 516, and 1 1S chrome alloys.

[0112] Those of ordinary skill are familiar with commercially available catalysts for use in a Fisher-Tropsch synthesis. These catalysts include, without limitation, those disclosed and taught by U. S. Patent Application Serial No. 10/776, 297 entitled"Fischer-Tropsch Synthesis Using Microchanel Technology and Novel Catalyst and Microchannel Reactor, "the disclosure of which is hereby incorporated by reference.

10113] It is also within the scope of the present invention that the reactors 32000 be removable from the manifolds 32200,32400, 32600. In this manner, the manifolds 32200,32400, 32600 are bolted to the reactors 32000 with an interposing gasket to ensure a fluidic seal between the manifolds and reactors. Exemplary gaskets for use with this alternate exemplary embodiment include, without limitation, Garlock Helicoflex Spring Energized Seals, graphite gaskets, reinforced graphite, corrugated metal/spiral wound gaskets, and elastomeric seals. As discussed previously, welding of the reactors 32000 introduces high local temperatures that may degrade or destroy catalyst in proximity to the weld and/or result in delaminations. In addition, the availability to quickly remove one or more reactors 32000 from the vessel 30200 obviates the need to provide separate catalyst refurbishment lines. In such an alternate exemplary embodiment, the refurbishment of active metal catalysts can occur away from the pressure vessel 30400, as well as the ability to perform tests upon the reactors 32000 away from the pressure vessel 30400.

[0114] Following from the above description and invention summaries, it should be apparent to those of ordinary skill in the art that, while the apparatuses and methods described herein and illustrated constitute exemplary embodiments of the present invention, it is understood that the invention is not limited to these precise embodiments and that changes may be made therein without departing from the scope of the invention as defined by the claims. Additionally, it is to be understood that the invention is defined by the claims and it is not intended that any limitations or elements describing the exemplary embodiments set forth herein are to be incorporated into the claims unless explicitly recited in the claims themselves. Likewise, it is to be understood that it is not necessary to meet any or all of the recited advantages or objects of the invention disclosed herein in order to fall within the scope of any claim, since the invention is defined by the claims and since inherent and/or unforeseen advantages of the present invention may exist even though they may not have been explicitly discussed herein.

[0115] What is claimed is: