Patent Application
20230340336
None.
The transformation of chemical feedstocks into products relies on reactors with controlled internal conditions. Conversion of hydrocarbon feedstocks such as natural gas containing methane with strong carbon-hydrogen bonds is particularly challenging and typically utilizes reactors containing catalysts and/or making use of high temperatures. A major limitation in chemical reaction engineering is the inability to perform very high temperature reactions efficiently at high pressure due to the limitations of reactor construction materials. For reversible reactions, equilibrium limitations, can also make very high temperatures desirable but limited by reactor material considerations. This is especially true in corrosive environments. Above approximately 1000° C. few moderate cost materials can be used for construction of safe pressure vessels.
One example of an important reaction that would be favorable at very high temperatures is natural gas pyrolysis. In pyrolysis of hydrocarbon reactants, the molecules are dehydrogenated, cracked and broken down into lighter hydrocarbons, olefins, aromatics, and/or solid carbon. It is generally cost effective to operate at high pressures and equilibrium restrictions favor the use of very high temperatures. A catalyst may be used as well to hasten reaction rates and improve selectivities. Methane pyrolysis by rapid heating in a reaction zone has been investigated. Subatmospheric pressures and specific ranges of velocities of hydrocarbon gases through the reaction zone are disclosed in U.S. Pat. No. 3,156,733. Heat is supplied by burning of hydrocarbons.
A high-temperature arc furnace can be used in the pyrolysis of methane to achieve high conversions to hydrogen and a valuable carbon black co-product. U.S. Pat. No. 3,389,189 is an example of patents relating to production of acetylene by an electric arc. The furnace operation must be paused for removal of the solid carbon product. If the carbon produced from natural gas pyrolysis could be efficiently made and conveniently removed from the vessels, pyrolysis would be more useful in industry.
The conversion of methane, natural gas and other alkanes to unsaturated hydrocarbons and hydrogen by subjecting the hydrocarbons to high temperatures produced by electromagnetic radiation or electrical discharges has been extensively studied and disclosed in U.S. Pat. No. 5,277,773 using microwave radiation to produce an electric discharge and U.S. Pat. No. 5,131,993 which discloses a method using a microwave discharge plasma and a carrier gas, such as oxygen, hydrogen and nitrogen, and, generally, a catalyst.
In an embodiment, a process for performing high temperature reactions comprises introducing reactants into a reactor vessel, generating a high temperature within the reactor vessel, exposing a first portion of the reactants to the high temperature, and reacting the first portion of the reactants based on contact with the high temperature to produce one or more products. The high temperature is higher than a lower temperature of a wall of the reactor vessel, and a temperature gradient is generated between the high temperature and the lower temperature of the wall. A second portion of the reactants are not exposed to the high temperature, and the second portion of the reactants do not react.
In an embodiment, a thermal gradient reactor comprises a reactor vessel comprising a reactor wall, an inner wall disposed within the reactor vessel, wherein an annular space is created within the reactor vessel between the reactor wall and the inner wall, a reaction zone defined within the inner wall, and a heat source disposed within the inner wall. The heat source is configured to generate a reaction temperature within the reaction zone, and the annular space and the reaction zone are configured to pass a reactant gas through an inlet, through the annular space, through the reaction zone, and out an outlet.
In an embodiment, a high temperature reaction process comprises passing a reactant gas into a reactor vessel, heating a heat source to generate a high temperature at the heat source, reacting at least a portion of the reactant within the reactor vessel based on generating the high temperature to create reaction products comprising solid carbon, cooling the heat source to maintain a wall of the reactor vessel below a threshold temperature, depositing the solid carbon within the reactor vessel, repeating the passing, heating, and reacting until an accumulation of solid carbon forms in the reactor vessel, and removing the solid carbon from the reactor vessel to recover the solid carbon. The heat source is only heated for a first time period, and the threshold temperature is below the high temperature.
In an embodiment, a high temperature reaction process comprises generating a high temperature at a first location within a liquid, passing a reactant gas through the high temperature within the liquid, forming reaction products based on the reactant gas passing through the high temperature, passing the reaction products away from the first location, cooling the reaction products based on passing the reaction products through the liquid away from the first location, and removing at least a portion of the reaction products from the reactor vessel. The liquid is within a reactor vessel, and the liquid away from the first location is at a lower temperature.
In an embodiment, a non-isothermal reactor comprises a pressure vessel, a plurality of high-temperature heat sources disposed within the pressure vessel, at least one heat shield, an inlet configured to introduce reactants into the pressure vessel, and an outlet configured to pass products out of the pressure vessel. The high-temperature heat source is configured to create a spatially varying temperature gradient within heat shield.
In an embodiment, a reaction process using a non-isothermal reactor comprises contacting a hydrocarbon with a high-temperature heat source within a pressure vessel, generating solid carbon and hydrogen in response to contacting the hydrocarbon with the high-temperature heat source, radiating heat from the high-temperature heat source, absorbing, by the solid carbon, the radiating heat, heating the solid carbon to a reaction temperature, contacting the hydrocarbon with the heated solid carbon to generate additional solid carbon and hydrogen, and shielding the radiating heat from a wall of the pressure vessel based on absorbing the radiating heat with the solid carbon.
These and other features will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings and claims.
For a more complete understanding of the present disclosure, reference is now made to the following brief description, taken in connection with the accompanying drawings and detailed description:
As used herein, a reactant refers to any substance that enters into and is potentially altered in the course of a chemical transformation. A product refers to a substance resulting from a set of conditions in a chemical or physical transformation. A reactor refers to a container or apparatus in which substances are made to undergo chemical transformations. A catalyst refers to a substance that increases the rate of a chemical reaction or enables a chemical reaction to proceed under different conditions than otherwise possible. A condensed phase refers to a liquid and/or solid. Natural gas refers to a collection of mostly methane with much smaller amounts of other light alkanes (ethane, propane, etc.) and trace impurities (CO2, water, etc). Pyrolysis refers to the decomposition of a hydrocarbon to solid carbon and hydrogen.
In the past systems that have used electric arcs and other means for the production of plasmas, whereby the electronic temperature was very high and not in equilibrium with the nuclear temperature in the atoms and molecules, carbon black can be produced efficiently in commercial practice. However, these technologies are distinct from the present systems and methods and designs in that the goal and operating principals of the presently practiced plasma based systems do not rely or make use of a spatially varying temperature gradient. Further, plasmas in reactant gases of commercial interest cannot be sustained at high pressures. The systems and methods of the present disclosure are suitable for very high pressure operation with a wide range of choices of materials. In other systems, electric heating of platinum filaments was utilized by Q. Sun, et al. to achieve high temperatures at very short reaction (residence) times to obtain selective production of specific gaseous chemical intermediates (Energy & Fuels, 2000, 14, 490-494), product selectivity was obtained solely based on short reaction times and had a temperature gradient been important the selectivity would have been poor (undesirable). The present systems and methods are distinct based on the innovative use of spatial temperature gradients to ensure that no reactor structural material is required to sustain high temperatures, and in the production of desirable solid carbon. In some aspects, the reactor structural materials may not be able to maintain structural integrity at the pressure of the reactor and the temperature of the actual reaction. Further distinctions include management of the large radiative heat emission through the thermal design.
If pyrolysis were efficient, as enabled by the present systems and methods, then fossil based hydrocarbons such as methane could be used to make hydrogen without producing carbon dioxide. At present, industrial hydrogen is produced primarily using the steam methane reforming (SMR) process, and the product effluent from the reactors contains not only the desired hydrogen product but also other gaseous species including carbon oxides (CO/CO2) and unconverted methane. Separation of the hydrogen for shipment or storage and separation of the methane for recirculation back to the reformer is carried out in a pressure swing adsorption (PSA) unit, a costly and energy-intensive separation. This separation process exists as an independent unit after reaction. Overall the existing commercial process produces significant amounts of carbon dioxide.
The systems and methods disclosed herein include chemical reactors designed whereby spatial and temporal temperature gradients and/or reactor zones of distinctly different temperatures allow temperature dependent chemical reactions to occur at different rates in different reaction zones, thereby providing unique flexibility in selectivity and reactor design while performing very high temperature chemistry in reactors made with materials suitable for less demanding environments. In addition, the processes, systems, and methods disclosed herein include chemical reactors designed specifically with temperature gradients in or around localized high temperature heat sources which provide for reactor zones of distinctly different temperatures which allow temperature dependent chemical reactions to occur at different rates in the different reactor zones, thereby providing unique flexibility in selectivity and reactor design while performing very high temperature chemistry in reactors made with materials suitable for less demanding environments. One or more embodiments discussed herein allow equilibrium limited reactions normally requiring high temperatures to be performed at lower or more moderate temperatures. Accordingly, the present systems and methods provide a novel means for obtaining efficient conversion of feedstocks while maintaining the reactor temperature or the reactor materials temperature such that low-cost materials may be utilized.
The present systems and methods consist of A) a process for the conversion of reactant molecules containing hydrogen and carbon(s) such as those in natural gas that may include, i) the pretreatment of the reactants, ii) the reaction of the reactants in a reactor that has a large temperature gradient by design, and iii) the separation of the products which contain hydrogen and carbon, and, B) chemical reactors with large thermal gradients inside the reactor by design to increase the rate of reaction.
Although, many prior processes are known by practioners that include chemical reactors that are non-isothermal, the present systems and methods are novel and distinct because, a large thermal gradient is created by design to allow extremely fast reaction rates in high temperature zones while the conditions within the reactor in other zones are milder. In general, chemical reactors are typically classified as isothermal when the reactor is designed to maintain a single temperature using a heat exchanger to add or remove reaction heat, or adiabatic when the reactor may be insulated and the temperature allowed to vary as the reaction proceeds and produces or consumes heat. The present systems and methods include reactors designed specifically with zones of very different temperatures within the same continuous reactor environment by design, thereby allowing for chemical conversions otherwise not possible with conventional reactor designs.
In some embodiments, the present systems and methods include reactors designed specifically with zones of very different temperatures within the same reactor environment by design to allow for chemical conversions otherwise not possible with conventional reactor designs. The basic systems and methods and novel aspects can be applied for reactions of gases and/or liquids whereby the reaction rates, mass, and heat transfer rates can have significant variability. In some embodiments, solid products can remain suspended in the gas or liquid fluid, thereby assisting in removal of the solid products from the reactor.
As an important example, methane pyrolysis is an endothermic, reversible chemical reaction whereby one mole of methane is converted to 2 moles of hydrogen and 1 mole of solid carbon. At high pressure, thermodynamics make it impossible to achieve high methane conversion except at very high temperatures as seen in
Whereas thermodynamics set the maximum equilibrium conversion under any chemical pathway, chemical kinetics determine how fast equilibrium conversion is achieved. Although at 1 bar pressure and 1000° C. it is possible to achieve nearly 100% methane conversion, without a catalyst the reaction time required to achieve equilibrium conversion may be prohibitively long.
The basic concept of a temperature gradient reaction environment can be understood with reference to
The heat and mass balances of the reacting system can be readily modelled and the average temperature and methane conversion determined. Although the effective reaction rate constant typically will increase exponentially with temperature, ultimately the reaction rate will be mass transfer limited and model rate expression will need to reflect that limit.
Whereas the description above provides the basic idea of how a time and spatially varying temperature gradient can be used in an unstirred reactor to allow reactions in reactors made of modest materials, most reaction systems would employ flow reactors. In the case of a flow reactor, modelling requires the addition of terms describing flow and the use of fluid dynamics. In a simplified scheme,
As a specific example in a preferred embodiment, suppose the reactant stream is methane and we are examining pyrolysis, CH4→C+2H2 (ε=3 moles product per mole reactant).
In a conventional reactor at 1 second of reaction time there would be negligible conversion at 950° C. without a catalyst, and even at 10 sec there would not be equilibrium conversion. However, a methane reactant stream at 200° C. can be converted (65% conversion) in a thermally heterogeneous reactor with a heated zone at 1100° C. with 65% of the molar flow passing through it and heated to 1100° C. where conversion is 100% in under one second. When mixed with the cold stream the temperature of the exit stream is only approximately 963° C. Because of the reactor design, the reactor vessel walls are only in contact with the cold stream making the materials of construction choices simpler. An important element of the design is therefore the reactant flow design to ensure the hot zone is isolated from major structural materials under stress. In some aspects, the reactor structural materials may not be able to maintain structural integrity at the pressure of the reactor and the temperature of the actual reaction. For example, the temperature of the wall can be maintained at a lower temperature based on the second portion of the reactants not being heated significantly because of the temperature gradient, where not being heated significantly refers to being maintained below a temperature limit of the structural integrity of the wall. There are many alternatives to achieve this flow design, where some are described below in the examples.
Another aspect of the invention is the utilization of a very high temperature heat source (T>1200° C.) in specific reaction environments where energy transfer by atypical pathways is important. For endothermic reactions, energy must be transferred to the reactants at a rate in proportion to the reaction rate. The energy can only be added by: i) interaction of the methane with energy in gas phase matter, ii) interaction of methane with a hot condensed matter surface (convection), or iii) from electromagnetic radiation. A high temperature surface can transfer heat to the methane by both convection and radiation, the heat flux is the heat transferred into a unit volume by radiation and convection. To maintain the temperature the heat transferred into the volume must equal the heat required for the reaction. Since the radiation component of heat transfer increases as the 4th power of the source temperature, very high temperature sources transfer significant amounts of heat by radiation. Methane and the products of pyrolysis are strong absorbers of infrared radiation and significant heating of the vapor phase and developing solids surrounding the high temperature source will occur. The total heat added per unit area can be much greater than with a low temperature source.
Another important aspect of the invention making use of a high temperature source and temperature gradient for endothermic reactions such as methane pyrolysis as well as many other reactions where radical species are involved in the reaction pathway is the utilization of surface generated radicals. When hydrogen contacts a very high temperature source, it can dissociate and eject two hydrogen atoms into the gas phase. This reaction is very endothermic (ΔH=436 kJ/mole) and it cools the surface. Similarly, when methane contacts a very high temperature surface it can dissociate and eject a methyl and hydrogen radical into the gas phase also cooling the surface, (ΔH=439 kJ/mole). Radical ejection from the surface to the gas phase increases the rate of reaction within the gas where the radicals are injected.
A novel aspect of the systems and methods disclosed herein is the realization that the energy transfer and reaction rate enhancement in the region around a very high temperature surface is provided by the surface flux of activated chemical species ejected from the high temperature surface. Thus, the power delivered to the methane system is conveyed by: i) the radicals generated on the surface and ejected, ii) radiation emitted, and iii) convection. The power input from the source (electrical or combustion) is dissipated at the source surface into the production of active species ejected from the surface, blackbody radiation, and convection.
Prior systems, including those using plasma sources of heat, were limited in their operational pressure due to the materials of construction of the reactor pressure vessel walls. Based on the designs disclosed herein, the carbon formed during the reaction can be used to shield the high temperature source from radiation heat transfer losses by self-adsorption in the forming carbon around the heat source. The infrared radiation absorbed in the solid carbon can in turn heat the carbon particle (instead of transmitting it to the heat shield) forming another high temperature site for a high reaction rate (thermally autocatalytic). For example,
In previous systems for producing gaseous products such as acetylene and ethylene using high temperatures obtained by electric heating, generally the gas phase products were obtained from plasmas and without the benefit of a large thermal gradient and radiation shielding. In the designs disclosed herein, solid carbon is the desired product to be formed in the gas phase around the high temperature source. By virtue of the heat absorbing properties of the solid carbon formed and the radiation shielding around the source, the reactor materials used for the process can be standard for chemical reactors and be able to perform at very high reaction pressures. For example, the reactor pressures can be between atmospheric pressure up to about 100 bar, up to about 50 bar, up to 40 bar, up to about 30 bar, or up to about 20 bar.
It is also noteworthy that on heated surfaces solid chemicals can be deposited on the surface (e.g., coking, fouling). However, when a very high temperature surface is utilized solids do not form on the surface as the temperature exceeds the desorption temperature of all surface products. For hydrocarbon reactions, an important surface interaction is with hydrogen and methane.
The high temperature surfaces described here can be limited within the reaction environment as described herein to avoid raising the entire system to such high temperatures. Practical considerations limit the maximum operational temperature of the process. There are few low-cost materials of construction that can operate at temperatures above 1000° C. at high pressure, and removing heat from a system is not practical above approximately 900° C. Thus, although it is desirable to contact high pressure methane with a 1500° C. source to achieve rapid rates of reaction to high conversion, it is not desirable to have a reactor outlet temperature greater than approximately 900° C., and if hydrocarbons are present, the outlet should be less than approximately 700° C. to avoid coke formation. Another feature disclosed herein is the use of a quench gas mixed with the high temperature product stream, which helps to prevent the structural materials of the reactor from exposure to extreme temperatures.
Often the heat source will be very high temperature and emit significant amounts of infrared radiation that will be poorly absorbed by the gas phase reactants. Although this important pathway was neglected in the descriptions above, most important gas phase reactants do not themselves absorb the infrared thermal energy and the systems and methods disclosed herein include the use of selective shielding materials that can minimize absorption of the infrared radiation to avoid significant heating by undesirable structural elements. In an embodiment as shown schematically in
After passing by the heat source 2, no further heating of the gas stream may occur in the gas mixture of reactants and products. The flow velocity can be controlled to be high enough to keep solid carbon particles produced by the reaction suspended in the gas and transported out of the reactor in the product stream 7. The flow of the gas (e.g., the high velocity flow) can be laminar or turbulent flow. In some aspects, the flow of the gas can be turbulent and be introduced at a Reynolds number of greater than 500. The products in stream 7 can undergo conventional solid-gas separation in later units. Due to the material properties and high temperature of the heat source 2, no solid carbon (or substantially no solid carbon) may be deposited on the surface of the heat source 2.
In some embodiments, the heat source 2 can be made from a high temperature material and can be heated either electrically, or by way of hot combustion gasses. Suitable high temperature materials useful for the heat source 2 can include, but are not limited to, tungsten, molybdenum, tantalum (and their carbides) rhenium, and/or silicon carbide. The heat source 2 may be fashioned into a variety of shapes including a filament or wire.
The high temperature heat source 2 can be created and configured in a number of ways including but not limited to, AC or DC electrical resistive heating, inductive or microwave heating, and gas combustion. In some embodiments as shown in
In pyrolysis, solid carbon can be formed from hydrocarbons, and in this environment resistive current conducting elements or filaments or tubes in which exothermic reactions can be used to form the heat source 2 (e.g., formed from metals, etc.), can readily form carbides which may be more brittle than the material of the filament. In order to address this issue, material selection, fixation and electrical contact of the filaments, whether or not they are brittle, is contemplated. Further, the lifetimes of high temperature materials may be limited and provisions are included in the disclosed designs for rapidly changing the filamentous sources or continuously refilling or replacing the filament. When carbon is used as the high temperature heat source material erosion of the surface can be anticipated and replaced continuously. Maintaining a high surface temperature on the resistive conducting material or filament or tube or container within which an exothermic reaction is used for heating can be used as a way of preventing carbon accumulation on the heat sources. As an example, maintaining tantalum carbide above 2400° C. can limit or prevent carbon accumulation, and for tungsten carbide, carbon buildup above 2200° C. can be limited or prevented. Alternatively, allowing, by design, for the slow erosion of a carbon tube or filament to maintain a clean source surface can be used to prevent internal product accumulation with a facility or procedure to continuously or periodically replace all or part of the source.
In another embodiment, a means for producing a high temperature heat source is shown in
Another important innovation as disclosed herein is the management of the large radiation heat transfer through the reactor design and the use of heat shielding. A particularly novel element of the designs disclosed herein is the use of the reactant itself as thermal insulation to prevent the reactor walls from reaching high temperatures near the heat source accomplished by the specific reactor geometries.
Another embodiment of a reactor is shown in
The heat source can be heated using electricity or combustion sources as described herein. The heat source can be designed to have the reactants flow over or near the surface of the heat source, or in a tubular configuration, through an interior of the tube to allow for direct and/or indirect energy transfer from the heat source. Whereas in
The higher molecular weight intermediates and carbon produced in pyrolysis are denser than the methane and have strong infrared absorbance. In another embodiment shown in
The descriptions of single reaction zone reactors are not meant to limit the reactor configurations to relatively small reactors. This skilled in the art with the benefit of this disclosure can realize how to extend the inventive features to larger systems. In
Although a preferred application of the systems and methods disclosed herein is for the pyrolysis of high pressure natural gas from pipelines, the various embodiments disclosed herein can also be naturally suitable for management of hydrocarbon gases now flared and for relatively small sources of natural gas (stranded gas). In an embodiment, the gas source can be passed through the non-isothermal reactor system at a conversion of less than 100% and the products can be a mixture of solid carbon, hydrogen, and unconverted hydrocarbons. The product stream can then be passed into a solid-gas separator and the solid removed while the gas is used in an internal combustion powered generator or a fuel cell to produce electricity. The pyrolysis heat source can be powered either by a fraction of the electricity produced or by diverting a fraction of the product gas stream to combustion. The net result is electricity produced with far lower carbon dioxide emissions than would have resulted from direct use of the hydrocarbons.
Pyrolysis of gaseous hydrocarbon reactants is but one example of how the systems and methods disclosed herein can improve on existing chemical processes. Liquid reactants can similarly be processed and multi-phase products including gases and solids are also possible. In an example of a multi-phase process, a liquid reactant is heated in the temperature gradient, changing phase (possibly with reaction) to form a gas phase region around the high temperature heat source. Heat and mass transfer from the source, through the gas phase and into the liquid phase can all be controlled to maximize the production of the desired products while controlling the overall system conditions.
In an embodiment, a liquid hydrocarbon can be caused to flow concentrically around a coaxial high temperature heat source at a pressure of 1 to 100 bar. Contact with the heat source which is at a temperature above 1000° C. can vaporize the hydrocarbon and facilitate the pyrolysis reaction producing solid carbon and hydrogen gas at the pressure of the liquid.
In another embodiment, reference is made to
In another embodiment, a thermal gradient can be established within a reactor containing a electrically and/or thermally conducting liquid medium that does not participate chemically in the reaction but allows for the creation of the thermal gradient providing for very high reaction rates in localized high temperature zones. Such liquid media can include, but is not limited to, molten salts (including but not limited to NaCl, KCl, NaBr, KBr, and other metal halides, etc.) and molten metals (including but not limited to pure and alloy combinations including, Na, K, Li, Mg, Fe, Ni, Cu, Bi, Sn, Sb, Co, etc.). Reference is made to
Cooling the reactant gas or heat shield can also be done using a separate, non-reactive cooling fluid (liquid or gas). In one embodiment shown schematically in
As also shown in
An important implementation and novel use of the systems and methods disclosed herein is for hydrocarbon pyrolysis. In an embodiment shown schematically in
Solid carbon accumulation may generally be undesirable inside a flow reactor. and ideally all carbon produced can leave the reactor suspended in the gas phase products and unreacted reactants. An important distinction from prior systems is the design of the flow reactor system to maintain the solid product suspended within the reactant and product gas stream. Accommodation for this is in the flow design of the reactor which has a very high velocity in all sections of the reactor after reaching the hot reaction zone. In some aspects, the flow of the gas can be turbulent and be introduced at a Reynolds number of greater than 500. All surfaces can have an aerodynamic shape to avoid carbon build-up as part of the technology innovation. Further, because the hydrodynamic design is such to ensure high velocity, the reactor can be periodically cleaned to remove any accumulation by passing suspended solids (e.g., sand, particulates, etc.) to abrade off any accumulated carbon.
In some embodiments, solid carbon accumulation may be desirable in certain unmixed (batch reactor) configurations because technology already exists to remove the carbon efficiently and at low cost. In these embodiments, carbon can be allowed to accumulate as shown schematically in
Within the embodiment illustrated in
In some embodiments, a hydrocarbon gas 41 such as natural gas can be introduced into the process of
In another embodiment for natural gas pyrolysis shown schematically in
An important continuous process option is thereby made possible and disclosed herein, whereby, in the process shown in
Although continuous processes are often desirable, semi-continuous operation may find important applications whereby the solid product produced in the high temperature gradient reactor remains in the reactor for later removal, and only gas phase products leave the reactor.
An embodiment for natural gas pipeline enrichment is shown schematically in
In some embodiments, the system shown in
Because pyrolysis produces primarily carbon, removal of the carbon suspended in the gas flow is important. In an embodiment, the suspension of carbon in gaseous products exits the reactor at a temperature of less than 900° C. The stream can be cooled and the carbon separated from the gas phase stream using existing technologies. It is anticipated that there will be a small fraction of carbon residue that is retained within the reactor system and builds up over time. Another important novel aspect of the configurations disclosed herein is the addition of a feature for cleaning the deposits without disassembling the reactor. In some embodiments, the reactor system can be cleaned using an inert feed at higher velocity than is typically used during reaction and the suspension in the inert feed abrasive particles (sand) which, as the suspended abrasives pass through the reactor, will remove carbon residue and pass it out to the solid-gas separation systems.
In another embodiment of the process shown schematically in
The disclosure having been generally described, the following examples are given as particular embodiments of the disclosure and to demonstrate the practice and advantages thereof. It is understood that the examples are given by way of illustration and are not intended to limit the specification or the claims in any manner.
In a specific example, methane is converted into hydrogen and carbon in the laboratory configuration shown
In another specific example, methane is converted into hydrogen and carbon in a flow reactor similar to the concept of
In another specific example, methane is converted into hydrogen and carbon in a flow reactor of larger diameter than Example 2. A 0.38 inch diameter quartz tube reactor with a reaction volume of 4 ml with a 10 cm tungsten filament heated electrically to approximately 2400° C. in the center. The methane residence time was varied between 0.4 and 2.4 seconds by changing the flow rates.
In another example, a 200 ml 316 stainless steel reactor is filled to 180 ml with liquid hexane at 30° C., as shown schematically in
In another example, shown schematically in
In another example, shown in photographs in
In an example, methane is converted into hydrogen and carbon in a batch reactor described schematically in
In another specific example, methane is converted into hydrogen and carbon in a flow reactor similar to the concepts of
In another specific example, a reactor which converted methane to hydrogen and solid carbon in a high temperature zone, was brought to moderate temperatures by a quench gas of nitrogen described in
Having described various systems and methods, certain aspects can include, but are not limited to (referring also to the figures):
In a first aspect, an integrated process for conversion of chemical feedstocks into chemical products, the process comprising: contacting a feedstock with a high-temperature heat source in a non-isothermal reactor; producing products comprising hydrogen and carbon based on the contacting; and separating the products from any reacted feedstock; and producing at least one product stream from the separating.
A second aspect can include the process of the first aspect, further comprising: treating a hydrocarbon feedstock to produce the feedstock.
A third aspect can include the process of the first or second aspect, further comprising: pre-heating the feedstock in at least one heat exchanger prior to contacting the feedstock with the high-temperature heat source;
A fourth aspect can include the process of any one of the first to third aspects, further comprising: cooling the products from the non-isothermal reactor prior to separating the products.
In a fifth aspect, a reactor system can comprise a subsection for feedstock pre-treatment and heat exchange, a reactor for transforming feedstocks to products at high pressures using a non-isothermal reactor with a high temperature heat source, a subsection for product heat exchange, and a separation subsystem for separating products from byproducts and unreacted feedstock.
In a sixth aspect, an integrated process for conversion of alkane containing chemical feedstocks into molecular hydrogen and solid carbon comprises: a heat exchanger system for preheating the alkane feedstock, a non-isothermal reactor where the chemical reaction is accelerated by a spatially localized high temperature heat source producing primarily hydrogen gas and suspended solid carbon and where the high temperature products are intermixed with lower temperature chemicals such that the product stream leaving the reactor and in contact with reactor structures away from the heat source are at a lower temperature, a heat exchanger system for cooling the product stream, a subsystem for separating the suspended solid carbon from the gas phase product stream, and a subsystem for separating the hydrogen product from unreacted alkanes and reaction byproducts.
A seventh aspect can include the process of the sixth aspect, whereby natural gas at a pressure greater than 10 bar is the feedstock and it is preheated to a temperature greater than 500° C. and introduced at high velocity with a Reynolds number greater than 500 into a non-isothermal reactor with a heat source maintained at a temperature greater than 1500° C. which facilitates reaction to produce solid carbon suspended in the gas which is at a temperature lower than the heat source. The high temperature product stream is intermixed with a quenching stream within the reactor lowering the mixture temperature to less than 900° C. where it exits the reactor for subsequent cooling and separation.
In an eighth aspect, an integrated process for enriching high pressure natural gas pipelines in hydrogen by using the pipeline gas as a feedstock to a process which i) transforms the natural gas into hydrogen and solid carbon, and ii) removes the solid carbon and other products from hydrogen and methane, and iii) returns the hydrogen and methane to the pipeline.
In a ninth aspect, a chemical reactor for increasing the production of a desired product from reactants, comprises: a. a vessel; b. a localized high temperature heat source creating a spatially varying temperature gradient; c. an inlet for contacting reactants with the heat source; and d. an outlet for removing the desired products.
In a tenth aspect, a chemical reactor for production primarily of hydrogen and solid carbon from natural gas containing methane comprises: a. a steel pressure vessel; b. a localized high temperature heat source creating a spatially varying temperature gradient; c. an inlet for contacting reactants with the heat source; and d. an outlet for removing the desired products.
In an eleventh aspect, an integrated process for conversion of alkane containing chemical feedstocks into molecular hydrogen and solid carbon in a reactor maintained with spatially varying temperatures enabled by a localized high temperature heat source such that, i) the reaction rate in the vicinity of the heat source is maintained fast producing solid carbon suspended in the gas, ii) the heat consumed in the reaction and the infrared absorption by reactants and products reduces the heating of the reactants and reactor containment materials distant from the heat source.
In a twelfth aspect, an integrated process for enriching high pressure natural gas pipelines in hydrogen by using the pipeline gas as a feedstock to a process which i) transforms the natural gas into hydrogen and solid carbon, and ii) removes the solid carbon and other products from hydrogen and methane, and iii) returns the hydrogen and methane to the pipeline.
A thirteenth aspect can include the process of the eleventh or twelfth aspect whereby the source temperature in the reactor is greater than 1500 C and the pressure is greater than 5 bar.
A fourteenth aspect can include the process of the eleventh or twelfth aspect whereby the source temperature in the reactor is greater than 2000 C and the pressure is greater than 20 bar.
A fifteenth aspect can include the process of the eleventh or twelfth aspect whereby the high temperature source is surrounded by a material with a high reflectivity for thermal radiation.
A sixteenth aspect can include the process of the eleventh or twelfth aspect whereby the reactor pressure vessel is made from materials such as steel that is not rated for temperatures as high as the heat source at the reaction temperatures in the vicinity of the heat source.
In a seventeenth aspect, a reactor system for producing products from fluids (gas or liquid), comprises: 1) a reactor section comprising a feed inlet, a reactor outer wall, an annular space cooled partially by the inlet feed and an internal outlet to a second continuous reactor section enclosed in the reactor outer wall; and 2) a second reactor section located within said annular space and including: a. a flow channel causing the feed to pass around a centrally located localized heat source producing a large thermal gradient between the source and the channel wall which is coated with an infrared heat reflecting material on the inner surface facing the source, b. a high temperature heat source in fluid communication with the feed in the flow channel, and, c. a reactor outlet whereby hot reaction products produced in the vicinity of the heat source are mixed with unreactive, cooler, feed fluids that moved through the region of the heat source far from the source with relative thermal isolation thereby lowering the temperature of the intermixed materials.
An eighteenth aspect can include the reactor system of the seventeenth aspect whereby the reactor is for producing solid carbon and gaseous hydrogen from a hydrocarbon gas feed, and: a. the reactor section comprising a feed inlet, a reactor outer wall, an annular space is cooled partially by the hydrocarbon gas feed and with reactor walls made primarily from stainless steel and having an internal outlet to a second continuous section enclosed in the reactor outer wall; and b. a second reactor section located in said annular space and including: c. a flow channel made of a metal including but not limited to stainless steel which causes the hydrocarbon feed to pass around a centrally located heat source with the channel wall having an infrared reflecting material on the inner surface including but not limited to alumina, d. a high temperature heat source in communication with the hydrocarbon feed in the flow channel comprised of a refractory material (e.g. tungsten, molybdenum, or their carbides or silicides, or silicon carbide, heated with electricity or by a chemical reaction (combustion), and e. a reactor outlet whereby reaction products produced in the vicinity of the heat source including solid carbon suspended in the gases are mixed with unreacted, cooler, feed gas that moved through the region of the heat source a distance from the heat source with relative thermal isolation.
In a nineteenth aspect, a reactor system for producing products from fluids (gas or liquid), comprises: a. a reactor section in fluid communication comprising a pressure vessel which can be pre-filled with the reactant fluid and an outlet for semicontinuous removal of gas phase reaction products; and b. a second reactor section located within said reactor a distance apart from the pressure vessel walls whereby a localized heat source producing a large thermal gradient between the source and the pressure vessel walls with the high temperature heat source in fluid communication with the reactant fluid allowing rapid reaction rates in the local vicinity of the heat source.
In a twentieth aspect, a reactor system for producing products from gas phase reactants at high temperatures with a large thermal gradient comprises: a. a reactor pressure vessel containing a non-reacting liquid in fluid communication with the pressure vessel walls with an inlet to allow gas phase reactants to enter the liquid and an outlet for removal of gas phase reaction products and unreacted reactants; and b. a high temperature localized heat source in fluid communication with the non-reacting liquid that produces a very high localized temperature in the liquid through which reactant gases in bubbles are made to move where they react in the high temperature environment.
In a twenty first aspect, a process for pyrolysis producing solid carbon and hydrogen from gaseous hydrocarbons uses solid particulates suspended in a high velocity carrier gas are added to remove accumulated carbon within the reactor body.
In a twenty second aspect, a process for pyrolysis producing solid carbon and hydrogen from gaseous hydrocarbons uses solid particulates are introduced in the reactant stream to specifically absorb infrared radiation from a high temperature source or heat thereby facilitating the heating of the gas within the reactor.
In a twenty third aspect, an integrated process for performing reactions requiring very high temperatures that cannot be tolerated by the reactor structural materials is disclosed whereby reactants are introduced into a reactor containing a heat source which operates with a temperature gradient such that only a fraction of the reactants are exposed to the high reaction temperatures while the reactor structural materials are only in contact with a mixture of reactants and products at a reduced temperature below the very high reaction temperatures.
A twenty fourth aspect can include the process of the twenty third aspect whereby the hydrocarbon reactants are primarily methane which are passed into the body of the reactor such that a fraction of the reactants are contacted with a high temperature heat source within the reactor at a temperature greater than 1400° C. and undergo decomposition to produce mostly solid carbon and hydrogen while a fraction of the reactants pass through colder regions of the reactor in contact with the structural elements of the reactor. The products and remaining reactants are mixed prior to leaving the reactor.
In a twenty fifth aspect, a thermal gradient reactor is disclosed whereby the heating elements are comprised of high temperature materials including but not limited to silicon carbide, tungsten, tungsten carbide, molybdenum, molybdenum carbide, molybdenum silicide, tantalum, tantalum carbide, carbon, nickel, chromium, rhenium, and high temperature materials containing their mixtures.
In a twenty sixth aspect, a thermal gradient reactor is disclosed whereby the heating elements are heated by electricity.
In a twenty seventh aspect, a thermal gradient reactor is disclosed whereby the heating elements are tubes heated internally by combustion or other exothermic chemical reactions.
In a twenty eighth aspect, a thermal gradient reactor is disclosed whereby the heating elements are semi-porous tubes heated by reaction of a portion of the reactant gas with oxygen on or near the surface of the heating element.
In a twenty ninth aspect, a thermal gradient reactor is disclosed whereby the reactant flow is of high velocity and laminar.
In a thirtieth aspect, a thermal gradient reactor is disclosed whereby the reactant flow is of low or zero velocity, and the reactant diffuses within the reactor.
In a thirty first aspect, a thermal gradient reactor is disclosed whereby the reactant flow is of high velocity and turbulent.
In a thirty second aspect, a thermal gradient reactor is disclosed whereby the heat source is surrounded by an infrared reflecting material, including but not limited to alumina.
In a thirty third aspect, a thermal gradient reactor is disclosed whereby the thermal gradient is maintained by the specific flow profile of the reactants.
In a thirty fourth aspect, a thermal gradient reactor is disclosed whereby accumulation of carbon within the reactor is removed periodically by suspending abrasive fine particles in a high velocity gas flow made to move through the reactor and contact carbon accumulated on the reactor structural elements and suspending that carbon in the gas moving through the reactor.
In a thirty fifth aspect, a thermal gradient reactor is disclosed whereby the reactor is configured such that a solid product is produced in the gas which has a high infrared absorption and serves to shield the high temperature source from radiative heat flow and itself is heated serving as a high temperature source for additional reaction.
In a thirty sixth aspect, a thermal gradient reactor is disclosed whereby the high temperature heat source is created by a semiporous barrier between the reactor and the source volume and the heat generated by the combustion of reactant gas in the source volume. The semiporous barrier may consist of a high temperature material such as a ceramic (including but not limited to materials containing alumina, silicon carbide, zirconia) or sintered high temperature metal (including but not limited to tungsten, molybdenum).
In a thirty seventh aspect, an alkane pyrolysis process for producing hydrogen gas and solid carbon in a large thermal gradient produced by a localized high temperature heat source at a temperature around which the alkane gas reacts in the high temperature environment to produce the gas phase products and solid carbon suspended in the gas and where the reactor walls are maintained at a temperature far lower than the source temperature is disclosed.
A thirty eighth aspect can include the process of the thirty seventh aspect, whereby the source temperature in the reactor is greater than 1500 C and the pressure is greater than 5 bar.
A thirty ninth aspect can include the process of the thirty seventh aspect, whereby the source temperature in the reactor is greater than 2000 C and the pressure is greater than 20 bar.
A fortieth aspect can include the process of the thirty seventh aspect, whereby the high temperature source is surrounded by a material with a high reflectivity for thermal radiation.
A forty first aspect can include the process of the thirty seventh aspect, whereby the reactor pressure vessel is made from materials such as steel that is not rated for temperatures as high as the heat source at the reaction temperatures in the vicinity of the heat source.
In a forty second aspect, a reactor system for producing products from fluids (gas or liquid) comprises: 1) a reactor section comprising a feed inlet, a reactor outer wall, an annular space cooled partially by the inlet feed and an internal outlet to a second continuous reactor section enclosed in the reactor outer wall; and 2) a second reactor section located within said annular space and including: a. a flow channel causing the feed to pass around a centrally located localized heat source producing a large thermal gradient between the source and the channel wall which is coated with an infrared heat reflecting material on the inner surface facing the source, b. a high temperature heat source in fluid communication with the feed in the flow channel, and c. a reactor outlet whereby hot reaction products produced in the vicinity of the heat source are mixed with unreactive, cooler, feed fluids that moved through the region of the heat source far from the source with relative thermal isolation thereby lowering the temperature of the intermixed materials.
A forty third aspect can include the reactor system of the forty second aspect, whereby the reactor is for producing solid carbon and gaseous hydrogen from a hydrocarbon gas feed, and: a. the reactor section comprising a feed inlet, a reactor outer wall, an annular space is cooled partially by the hydrocarbon gas feed and with reactor walls made primarily from stainless steel and having an internal outlet to a second continuous section enclosed in the reactor outer wall; and b. a second reactor section located in said annular space and including: c. a flow channel made of a metal including but not limited to stainless steel which causes the hydrocarbon feed to pass around a centrally located heat source with the channel wall having an infrared reflecting material on the inner surface including but not limited to alumina, d. a high temperature heat source in communication with the hydrocarbon feed in the flow channel comprised of a refractory material (e.g. tungsten, molybdenum, or their carbides or silicides, or silicon carbide, heated with electricity or by a chemical reaction (combustion), and e. a reactor outlet whereby reaction products produced in the vicinity of the heat source including solid carbon suspended in the gases are mixed with unreacted, cooler, feed gas that moved through the region of the heat source a distance from the heat source with relative thermal isolation.
In a forty fourth aspect, a reactor system for producing products from fluids (gas or liquid), comprises: a. a reactor section in fluid communication comprising a pressure vessel which can be pre-filled with the reactant fluid and an outlet for semicontinuous removal of gas phase reaction products; and b. a second reactor section located within said reactor a distance apart from the pressure vessel walls whereby a localized heat source producing a large thermal gradient between the source and the pressure vessel walls with the high temperature heat source in fluid communication with the reactant fluid allowing rapid reaction rates in the local vicinity of the heat source.
In a forty fifth aspect, a reactor system for producing products from gas phase reactants at high temperatures with a large thermal gradient comprises: b. a reactor pressure vessel containing a non-reacting liquid in fluid communication with the pressure vessel walls with an inlet to allow gas phase reactants to enter the liquid and an outlet for removal of gas phase reaction products and unreacted reactants; and c. a high temperature localized heat source in fluid communication with the non-reacting liquid that produces a very high localized temperature in the liquid through which reactant gases in bubbles are made to move where they react in the high temperature environment.
A forty sixth aspect can include the reactor system of the forty fifth aspect, whereby the non-reacting liquid is a molten salt (including but not limited to NaCl, KCl, NaBr, KBr, and other metal halides) or a molten metal (including but not limited to pure and alloy combinations including, Na, K, Li, Mg, Fe, Ni, Cu, Bi, Sn, Sb, Co).
A forty seventh aspect can include the reactor system of the forty fifth aspect for producing hydrogen and solid carbon by pyrolysis of a hydrocarbon gas whereby the reactor vessel is a structural metal and operated a pressure greater than 5 bar and an average bulk liquid temperature of below 900 C and a hot source temperature of greater than 1500 C.
A forty eighth aspect can include the reactor system of the forty fifth aspect, where the hot source consists of electrodes within the non-reacting conducting liquid or otherwise in electromagnetic contact that when a voltage is applied cause an electrical current to flow within the liquid that heats the liquid between the electrodes where the current flows. The current density and local heating is shaped by the specific means of contacting the gas and the liquid.
A forty ninth aspect can include the reactor system of the forty fifth aspect, where the hot source consists of a tube or tubes inside of which high temperature exothermic chemical reactions occur separately and isolated from the reactor system including but not limited to silicon carbide tubes in which hydrogen combustion is occurring to heat the tube.
A fiftieth aspect can include the reactor system of any one of the previous aspects, where the temperature gradient in the reaction zone is greater than 10° C./cm.
A fifty first aspect can include the reactor system of any one of the previous aspects, where the temperature gradient in the reaction zone is greater than 100° C./cm.
A fifty second aspect can include the reactor system of any one of the previous aspects, where the temperature gradient in the reaction zone is greater than 1000° C./cm.
A fifty third aspect can include the reactor system of any one of the previous aspects, whereby an external gas or liquid not in contact with the reactants is used to remove heat from the reaction zone.
A fifty fourth aspect can include the reactor system of any one of the previous aspects, whereby the source of heat for producing the temperature gradients consists of multiple spatially separate sources.
In a fifty fifth aspect, e.g., as illustrated in
wherein a temperature gradient is generated between the high temperature and the lower temperature of the wall; exposing a first portion of the reactants 6 to the high temperature; reacting the first portion of the reactants based on contact with the high temperature to produce one or more products, wherein a second portion of the reactants are not exposed to the high temperature, and wherein the second portion of the reactants do not react.
A fifty sixth aspect can include the process of the fifty fifth aspect, where the wall of the reactor vessel cannot maintain structural integrity at a pressure of the reacting and the high temperature.
A fifty seventh aspect can include the process of the fifty fifth or fifty sixth aspect, further comprising: maintaining the lower temperature of the wall based on the second portion of the reactants not reacting.
A fifty eighth aspect can include the process of any one of the fifty fifth to fifty seventh aspects, wherein the reactants comprise methane.
A fifty ninth aspect can include the process of any one of the fifty fifth to fifty eighth aspects, wherein the high temperature is 1,400 C or greater.
A sixtieth aspect can include the process of any one of the fifty fifth to fifty ninth aspects, wherein the products comprise solid carbon and hydrogen gas.
A sixty first aspect can include the process of any one of the fifty fifth to sixtieth aspects, further comprising: mixing the products and the second portion of the reactants to produce a mixed product stream, wherein the mixed product stream is at a temperature lower than the high temperature; and passing the mixed product stream out of the reactor vessel.
A sixty second aspect can include the process of any one of the fifty fifth to sixty first aspects, wherein generating the high temperature comprises using a heating element 2 to generate the high temperature.
A sixty third aspect can include the process of the sixty second aspect, wherein heating element 2 is formed from silicon carbide, tungsten, tungsten carbide, molybdenum, molybdenum carbide, molybdenum silicide, tantalum, tantalum carbide, carbon, nickel, chromium, rhenium, or mixtures thereof.
A sixty fourth aspect can include the process of any one of the sixty second to sixty third aspects, wherein generating the high temperature comprises passing an electrical current through the heating element.
A sixty fifth aspect can include the process of the sixty second aspect, wherein the heating element comprises a tube, and wherein the process further comprises:
heating the tube internally using an exothermic reaction.
A sixty sixth aspect can include the process of the sixty fifth aspect, wherein the exothermic reaction comprises a combustion reaction.
A sixty seventh aspect can include the process of the sixty fifth or sixty sixth aspect, wherein the tube is porous, and wherein heating the tube comprises passing a third portion of the reactants through the tube; contacting the third portion of the reactants with oxygen within the tube; and combusting the third portion of the reactants within the tube based on contacting the third portion of the reactants with the oxygen.
A sixty eighth aspect can include the process of any one of the sixty fifth aspect to sixty seventh aspects, wherein the tube is formed from alumina, silicon carbide, zirconia, tungsten, molybdenum, or any combination thereof.
A sixty ninth aspect can include the process of any one of the fifty fifth aspect to sixty eighth aspects, wherein the reactants pass through the reactor vessel in a laminar flow.
A seventieth aspect can include the process of any one of the fifty fifth aspect to sixty ninth aspects, wherein the reactants pass through the reactor vessel in a turbulent flow.
A seventy first aspect can include the process of any one of the fifty fifth aspect to seventieth aspects, wherein generating the high temperature occurs within a heat shield, wherein the heat shield 3 is positioned within the reactor vessel, and wherein the process further comprises: shielding the wall of the reactor vessel from the high temperature using the heat shield.
A seventy second aspect can include the process of the seventy first aspect, wherein the first portion of the reactants passes through the heat shield 3 to be exposed to the high temperature, wherein the second portion of the reactants passes around an exterior of the heat shield and is not exposed to the high temperature.
A seventy third aspect can include the process of any one of the fifty fifth to seventy second aspects, further comprising: contacting an external surface of the wall with a coolant 26, and maintaining the lower temperature of the wall based on the contacting of the external surface of the wall with the coolant.
A seventy fourth aspect can include the process of any one of the fifty fifth to seventy third aspects, wherein generating the high temperature within the reactor vessel comprises using a plurality of heat sources 2 within the reactor vessel.
A seventy fifth aspect can include the process of the seventy fourth aspect, wherein the plurality of heat sources are arranged in series along the flow path within the reactor vessel.
In a seventy sixth aspect, e.g., as illustrated in
A seventy seventh aspect can include the reactor of the seventy sixth aspect, where the wall 1a of the reactor vessel cannot maintain structural integrity at a pressure of the reaction and the reaction temperature.
A seventy eighth aspect can include the reactor of the seventy sixth or seventy seventh aspect, wherein heat source 2 comprises heating filament, and wherein the heating filament is formed from silicon carbide, tungsten, tungsten carbide, molybdenum, molybdenum carbide, molybdenum silicide, tantalum, tantalum carbide, carbon, nickel, chromium, rhenium, or mixtures thereof.
A seventy ninth aspect can include the reactor of the seventy eighth aspect, wherein the heat source 2 comprises a tube configured to be heated using an exothermic reaction.
An eightieth aspect can include the reactor of the seventy ninth aspect, wherein the tube is porous.
An eighty first aspect can include the reactor of the seventy ninth or eightieth aspect, wherein the tube is formed from alumina, silicon carbide, zirconia, tungsten, molybdenum, or any combination thereof.
An eighty second aspect can include the reactor of any one of the seventy sixth to eighty first aspects, wherein the inner wall comprises a heat shield 3.
An eighty third aspect can include the reactor of any one of the seventy sixth to eighty second aspects, further comprising: a cooling jacket 1c disposed about the reactor vessel, wherein the cooling jacket defines a cooling annulus 28 about the reactor vessel, wherein the cooling jacket is configured to pass a coolant 26 in contact with an external surface of the reactor vessel 1 to maintain a temperature of a wall 1a of the reactor vessel lower than the reaction temperature.
An eighty fourth aspect can include the reactor of any one of the seventy sixth to eighty third aspects, wherein the heat source 2 comprises a plurality of heat sources within the reactor vessel.
An eighty fifth aspect can include the reactor of the eighty fourth aspect, wherein the plurality of heat sources are arranged in series along the flow path within the reactor vessel.
In an eighty sixth aspect, a thermal gradient reactor comprises an outer reactor wall; an inner wall disposed within the reactor vessel, wherein an annular space is created between the outer reactor wall and the inner wall; a reaction zone defined within the inner wall; and a heat source disposed within the inner wall, wherein the heat source is configured to generate a reaction temperature within the reaction zone, wherein the annular space and the reaction zone are configured to pass a first portion of a reactant gas through the annular space, a second portion of the reactant gas through the inner wall to create reaction products, and combine the first portion of the reactant gas and the reaction products past the reaction zone.
An eighty seventy aspect can include the reactor of the eighty sixth aspect, wherein the outer reactor wall is formed from steel or stainless steel.
An eighty eighth aspect can include the reactor of the eighty sixth or eighty seventh aspect, wherein the inner wall is formed from a high temperature metal of ceramic.
In an eighty ninth aspect, e.g., as illustrated in
A ninetieth aspect can include the process of the eighty ninth aspect, wherein the high temperature is greater than 1,500 C.
A ninety first aspect can include the process of the eighty ninth aspect, wherein the high temperature is greater than 2,000 C.
A ninety second aspect can include the process of any one of the eighty ninth to ninety first aspects, wherein a pressure in the reactor is greater than 5 bar.
A ninety third aspect can include the process of any one of the eighty ninth to ninety first aspects, wherein a pressure in the reactor is greater than 20 bar.
A ninety fourth aspect can include the process of any one of the eighty ninth to ninety third aspects, wherein the reactor vessel is formed from a material that is structurally unstable at the high temperature and pressure of the reacting.
A ninety fifth aspect can include the process of any one of the eighty ninth to ninety fourth aspects, wherein the reactants comprise methane.
A ninety sixth aspect can include the process of any one of the eighty ninth to ninety fifth aspects, wherein generating the high temperature comprises using a heating element 2 to generate the high temperature.
A ninety seventh aspect can include the process of the ninety sixth aspect, wherein heating element is formed from silicon carbide, tungsten, tungsten carbide, molybdenum, molybdenum carbide, molybdenum silicide, tantalum, tantalum carbide, carbon, nickel, chromium, rhenium, or mixtures thereof.
A ninety eighth aspect can include the process of the ninety sixth or ninety seventh aspect, wherein generating the high temperature comprises passing an electrical current through the heating element.
A ninety ninth aspect can include the process of the ninety sixth, wherein the heating element comprises a tube, and wherein the process further comprises:
heating the tube internally using an exothermic reaction.
A one hundredth aspect can include the process of the ninety ninth aspect, wherein the exothermic reaction comprises a combustion reaction.
A one hundred first aspect can include the process of the ninety ninth or one hundredth aspect, wherein the tube is porous, and wherein heating the tube comprises passing a third portion of the reactants through the tube; contacting the third portion of the reactants with oxygen within the tube; and combusting the third portion of the reactants within the tube based on contacting the third portion of the reactants with the oxygen.
A one hundred second aspect can include the process of any one of the ninety ninth to one hundred first aspect, wherein the tube is formed from alumina, silicon carbide, zirconia, tungsten, molybdenum, or any combination thereof.
In a one hundred third aspect, a thermal gradient reactor comprises a reactor vessel; a heat source disposed within the reactor vessel, wherein the heat source is configured to be cycled on to generate a high temperature, and cycled off, and wherein the heat source is configured to be cycled to generate a reaction temperature at the heat source while maintaining the reactor vessel below a threshold temperature; a reactant inlet; and a reactant outlet, wherein the reactant inlet and the reactant outlet are configured to pass a reactant gas into the reactor vessel in a semi-batch configuration.
In a one hundred fourth aspect, e.g., as illustrated in
A one hundred fifth aspect can include the process of the one hundred fourth aspect, wherein the liquid is a conductive liquid, and wherein generating the high temperature comprises passing an electrical current through the liquid at the first location.
A one hundred sixth aspect can include the process of the one hundred fifth aspect, wherein passing the electrical current through the liquid comprises: immersing electrodes 2A, 2 within the liquid; and applying a voltage across the electrodes; and generating the high temperature in response to current passing between the electrodes based on applying the voltage.
A one hundred seventh aspect can include the process of the one hundred fifth aspect, wherein one or more of the electrodes comprises an inlet tube, and wherein passing the reactant gas comprises passing the reactant gas through the inlet tube.
A one hundred eighth aspect can include the process of any one of the one hundred fourth to one hundred seventh aspects, wherein the liquid is non-reacting liquid, and wherein the non-reacting liquid comprises a molten salt or a molten metal.
A one hundred ninth aspect can include the process of the one hundred eighth aspect, wherein the molten salt comprises a halide salt.
A one hundred tenth aspect can include the process of the one hundred eighth aspect, wherein the molten metal comprise Na, K, Li, Mg, Fe, Ni, Cu, Bi, Sn, Sb, Co, alloys thereof, or combinations thereof.
A one hundred eleventh aspect can include the process of any one of the one hundred fourth to one hundred tenth aspects, wherein generating the high temperature at the first location comprises using a heating element 2 within the liquid at the first location 3.
A one hundred twelfth aspect can include the process of the one hundred eleventh aspect, wherein the heating element 2 comprises a tube (e.g., as illustrated in
A one hundred thirteenth aspect can include the process of any one of the one hundred fourth to one hundred twelfth aspects, wherein the reactor vessel comprises a structural metal.
A one hundred fourteenth aspect can include the process of any one of the one hundred fourth to one hundred thirteenth aspects, wherein the high temperature is greater than 1500° C., and wherein the lower temperature is below about 900° C.
A one hundred fifteenth aspect can include the process of any one of the one hundred fourth to one hundred fourteenth aspects, wherein a temperature gradient within the reactor vessel is greater than 10° C./cm.
A one hundred sixteenth aspect can include the process of any one of the one hundred fourth to one hundred fourteenth aspects, wherein a temperature gradient within the reactor vessel is greater than 100° C./cm.
A one hundred seventeenth aspect can include the process of any one of the one hundred fourth to one hundred fourteenth aspects, wherein a temperature gradient within the reactor vessel is greater than 1000° C./cm.
A one hundred eighteenth aspect can include the process of any one of the one hundred fourth to one hundred seventeenth aspects, further comprising: contacting an external surface of the reactor vessel with a coolant 26, and maintaining a lower temperature of a wall 1a of the reactor vessel based on the contacting of the external surface of the reactor vessel 1 with the coolant 26.
In a one hundred nineteenth aspect, a process for conversion of chemical feedstocks into chemical products comprises contacting a feedstock with a high-temperature heat source in a non-isothermal reactor; producing products based on the contacting; and separating the products from at least a portion of unreacted feedstock; and producing at least one product stream from the separating.
A one hundred twentieth aspect can include the process of the one hundred nineteenth aspect, wherein the feedstock comprises a hydrocarbon stream.
A one hundred twenty first aspect can include the process of the one hundred nineteenth or one hundred twentieth aspect, wherein the feedstock comprises natural gas.
A one hundred twenty second aspect can include the process of the one hundred twentieth or one hundred twenty first aspect, wherein the products comprise hydrogen and solid carbon.
A one hundred twenty third aspect can include the process of the one hundred twenty second aspect, further comprising: removing at least a portion of the solid carbon in the products prior to separating the products from any unreacted feedstock.
A one hundred twenty fourth aspect can include the process of any one of the one hundred nineteenth to one hundred twenty third aspects, further comprising: treating a raw feedstock to produce the feedstock.
A one hundred twenty fifth aspect can include the process of the one hundred twenty fourth aspect, wherein treating the raw feedstock comprises: removing one or impurities from the raw feedstock to produce the feedstock.
A one hundred twenty sixth aspect can include the process of any one of the one hundred nineteenth to one hundred twenty fifth aspects, further comprising: pre-heating the feedstock in at least one heat exchanger prior to contacting the feedstock with the high-temperature heat source.
A one hundred twenty seventh aspect can include the process of the one hundred twenty sixth aspect, wherein pre-heating the feedstock comprises heating the feedstock to a temperature between about 500° C. and about 900° C.
A one hundred twenty eighth aspect can include the process of any one of the one hundred nineteenth to one hundred twenty seventh aspects, wherein the high-temperature heat source is at a temperature of 1500° C. or greater.
A one hundred twenty ninth aspect can include the process of any one of the one hundred nineteenth to one hundred twenty eighth aspects, further comprising: maintaining a wall of the non-isothermal reactor at a temperature below 1000° C. during the contacting of the feedstock with the high-temperature heat source.
A one hundred thirtieth aspect can include the process of any one of the one hundred nineteenth to one hundred twenty ninth aspects, further comprising: cooling the products from the non-isothermal reactor prior to separating the products.
A one hundred thirty first aspect can include the process of the one hundred thirtieth aspect, wherein cooling the products comprises: mixing the products with a cooling stream; and quenching the product stream based on the mixing.
A one hundred thirty second aspect can include the process of the one hundred thirty first aspect, wherein the cooling stream comprises a cooled stream recycled from the separation of the products.
A one hundred thirty third aspect can include the process of any one of the one hundred thirtieth to one hundred thirty second aspects, wherein cooling the products comprises: cooling the products to a temperature of 900 C or less.
A one hundred thirty fourth aspect can include the process of any one of the one hundred nineteenth to one hundred thirty third aspects, further comprising: recycling at least a portion of the unreacted feedstock from the separating to an inlet of non-isothermal reactor.
A one hundred thirty fifth aspect can include the process of any one of the one hundred nineteenth to one hundred thirty fourth aspects, wherein the products comprise hydrogen, and where the process further comprises: recycling at least a portion of the hydrogen from the separating to an inlet of the non-isothermal reactor; and preventing coking within the non-isothermal reactor based on the presence of the recycled hydrogen.
A one hundred thirty sixth aspect can include the process of any one of the one hundred nineteenth to one hundred thirty fifth aspects, wherein the feedstock is introduced into the non-isothermal reactor with a Reynolds number greater than 500.
In a one hundred thirty seventh aspect, a process for conversion of chemical feedstocks into chemical products comprises: contacting a feedstock with a high-temperature heat source in a non-isothermal reactor; producing products based on the contacting, wherein the products comprise a gaseous product and a solid product; passing gaseous product out of the non-isothermal reactor; retaining the solid product in the non-isothermal reactor; separating the gaseous product from at least a portion of unreacted feedstock; and producing at least one product stream from the separating.
A one hundred thirty eighth aspect can include the process of the one hundred thirty seventh aspect, further comprising: ceasing the contacting of the feedstock with the high-temperature heat source; removing the solid product from the non-isothermal reactor; and reintroducing the feedstock to contact the feedstock with the high-temperature heat source.
A one hundred thirty ninth aspect can include the process of the one hundred thirty seventh or one hundred thirty eighth aspect, wherein the non-isothermal reactor comprises: a first reaction chamber; a second reaction chamber; and an inlet valve configured to direct the feedstock into the first reaction chamber or the second reaction chamber; and an outlet valve configured to direct the gaseous product and the unreacted feedstock out of the first reaction chamber or the second reaction chamber, respectively.
A one hundred fortieth aspect can include the process of any one of the one hundred thirty seventh to one hundred thirty ninth aspects, wherein the non-isothermal reactor comprises: a plurality of reaction chambers connected in parallel; one or more inlet valves configured to direct the feedstock into the first reaction chamber of the plurality of reaction chambers; and one or more outlet valves configured to direct the gaseous product and the unreacted feedstock out of the first reaction chamber of the plurality of reaction chambers.
A one hundred forty first aspect can include the process of any one of the one hundred thirty seventh to one hundred fortieth aspects, wherein the feedstock comprises a hydrocarbon stream.
A one hundred forty second aspect can include the process of any one of the one hundred thirty seventh to one hundred forty first aspects, wherein the feedstock comprises natural gas.
A one hundred forty third aspect can include the process of any one of the one hundred forty first to one hundred forty second aspects, wherein the gaseous product comprises hydrogen and wherein the solid product comprises solid carbon.
A one hundred forty fourth aspect can include the process of any one of the one hundred thirty seventh to one hundred forty third aspects, further comprising: treating a raw feedstock to produce the feedstock.
A one hundred forty fifth aspect can include the process of the one hundred forty fourth aspect, wherein treating the raw feedstock comprises: removing one or impurities from the raw feedstock to produce the feedstock.
A one hundred forty sixth aspect can include the process of any one of the one hundred thirty seventh to one hundred forty fifth aspects, further comprising: pre-heating the feedstock in at least one heat exchanger prior to contacting the feedstock with the high-temperature heat source.
A one hundred forty seventh aspect can include the process of the one hundred forty sixth aspect, wherein pre-heating the feedstock comprises heating the feedstock to a temperature between about 500° C. and about 900° C.
A one hundred forty eighth aspect can include the process of any one of the one hundred thirty seventh to one hundred forty seventh aspects, wherein the high-temperature heat source is at a temperature of 1500° C. or greater.
A one hundred forty ninth aspect can include the process of any one of the one hundred thirty seventh to one hundred forty eighth aspects, further comprising: maintaining a wall of the non-isothermal reactor at a temperature below 1000° C. during the contacting of the feedstock with the high-temperature heat source.
A one hundred fiftieth aspect can include the process of any one of the one hundred thirty seventh to one hundred fiftieth aspects, further comprising: cooling the gaseous product from the non-isothermal reactor prior to separating the gaseous product.
A one hundred fifty first aspect can include the process of the one hundred fiftieth aspect, wherein cooling the products comprises: mixing the products with a cooling stream; and quenching the product stream based on the mixing.
A one hundred fifty second aspect can include the process of the one hundred fifty first aspect, wherein the cooling stream comprises a cooled stream recycled from the separation of the gaseous product.
A one hundred fifty third aspect can include the process of any one of the one hundred fiftieth to one hundred fifty second aspects, wherein cooling the gaseous product comprises: cooling the gaseous product to a temperature of 900 C or less.
A one hundred fifty fourth aspect can include the process of any one of the one hundred thirty seventh to one hundred fifty fourth aspects, wherein the feedstock comprises natural gas from a pipeline, and further comprising: passing the at least one product stream to the pipeline.
In a one hundred fifty fifth aspect, e.g., as illustrated in
A one hundred fifty sixth aspect can include the reactor of the one hundred fifty fifth aspect, wherein the pressure vessel 1 is formed from steel, nickel, and/or alloys thereof.
A one hundred fifty seventh aspect can include the reactor of the one hundred fifty fifth or one hundred fifty sixth aspect, wherein high-temperature heat source is an electrical heat source or a combustion heat source.
A one hundred fifty eighth aspect can include the reactor of any one of the one hundred fifty fifth to one hundred fifty seventh aspects, further comprising: a quenching gas inlet 76a configured to introduce a quenching stream 76 between an interior of the pressure vessel and an exterior of the heat shield 3, wherein the outlet 7a is configured to pass a mixture of the products and the quenching gas 76 out of the pressure vessel 1.
A one hundred fifty ninth aspect can include the reactor of any one of the one hundred fifty fifth to one hundred fifty eighth aspects, wherein the high-temperature heat source is disposed coaxially within the heat shield.
A one hundred sixtieth aspect can include the reactor of any one of the one hundred fifty fifth to one hundred fifty eighth aspects, wherein the high-temperature heat source 2 is disposed about an interior border of the heat shield 3.
A one hundred sixty first aspect can include the reactor of any one of the one hundred fifty fifth to one hundred sixtieth aspects, wherein the inlet is configured to generate a cyclonic flow field 73b within the heat shield (e.g. as illustrated in
A one hundred sixty second aspect can include the reactor of any one of the one hundred fifty fifth to one hundred sixty first aspects, wherein the high-temperature heat source comprises a rod or tube.
A one hundred sixty third aspect can include the reactor of any one of the one hundred fifty fifth to one hundred sixty second aspects, wherein the high-temperature heat source is formed from tungsten, tungsten carbide, molybdenum, molybdenum carbide, aluminum, aluminum oxide, zirconium, zirconium oxide, or combinations thereof.
In a one hundred sixty fourth aspect, a non-isothermal reactor comprises: a pressure vessel; a plurality of high-temperature heat sources disposed within the pressure vessel, at least one heat shield, wherein the high-temperature heat source is configured to create a spatially varying temperature gradient within heat shield; an inlet configured to introduce reactants into the pressure vessel; and an outlet configured to pass products out of the pressure vessel.
A one hundred sixty fifth aspect can include the reactor of the one hundred sixty fourth aspect, wherein the at least one heat shield comprises a plurality of heat shields, and wherein each heat shield of the plurality of heat shields is disposed about a corresponding high-temperature heat source of the plurality of high temperature heat sources.
A one hundred sixty sixth aspect can include the reactor of the one hundred sixty fourth aspect, wherein the at least one heat shield is disposed about the plurality of high-temperature heat sources within the pressure vessel.
A one hundred sixty seventh aspect can include the reactor of any one of the one hundred sixty fourth to one hundred sixty sixth aspects, wherein the pressure vessel is formed from steel, nickel, and/or alloys thereof.
A one hundred sixty eighth aspect can include the reactor of any one of the one hundred sixty fourth to one hundred sixty seventh aspects, wherein the plurality of high-temperature heat sources is an electrical heat source or a combustion heat source.
A one hundred sixty ninth aspect can include the reactor of any one of the one hundred sixty fourth to one hundred sixty eighth aspects, further comprising: a quenching gas inlet configured to introduce a quenching stream between an interior of the pressure vessel and an exterior of the at least one heat shield, wherein the outlet is configured to pass a mixture of the products and the quenching gas out of the pressure vessel.
In a one hundred seventieth aspect, e.g., as illustrated in
A one hundred seventy first aspect can include the process of the one hundred seventieth aspect, wherein the non-isothermal reactor comprises: the pressure vessel 1; the high-temperature heat source disposed within the pressure vessel; a heat shield 3 disposed about the high-temperature heat source within the pressure vessel, an inlet 6a configured to introduce reactants 6 into the pressure vessel; and an outlet 7a configured to pass products out of the pressure vessel 1.
A one hundred seventy second aspect can include the process of the one hundred seventieth or one hundred seventy first aspect, wherein the high-temperature heat source is at a temperature of 1500° C. or greater, or at a temperature of 2000° C. or greater.
A one hundred seventy third aspect can include the process of any one of the one hundred seventieth to one hundred seventy second aspects, wherein a pressure within the pressure vessel is at 5 bar or greater, or at 20 bar or greater.
A one hundred seventy fourth aspect can include the process of any one of the one hundred seventieth to one hundred seventy third aspects, wherein the hydrocarbon is contacted with the high-temperature heat source at a Reynolds number of 500 or greater.
A one hundred seventy fifth aspect can include the process of any one of the one hundred seventieth to one hundred seventy fourth aspects, e.g., as illustrated in
A one hundred seventy sixth aspect can include the process of any one of the one hundred seventieth to one hundred seventy fifth aspects, e.g., as illustrated in
A one hundred seventy seventh aspect can include the process of the one hundred seventy sixth aspect, wherein the suspended solids comprise sand.
A one hundred seventy eighth aspect can include the process of any one of the one hundred seventieth to one hundred seventy seventh aspects, further comprising: introducing a solid reactant with the hydrocarbon; absorbing, by the solid reactant, the radiating heat; heating the solid reactant to a reaction temperature; contacting the hydrocarbon with the heated solid reactant to generate the additional solid carbon and hydrogen.
A one hundred seventy ninth aspect can include the process of the one hundred seventy eighth aspect, wherein the solid reactant is solid carbon.
The process, reactor, or system of any of the aspects, wherein the reactants comprise hydrocarbons, the reacting comprises pyrolysis, the products comprise at least one of a hydrocarbon, carbon, or hydrogen.
Embodiments are discussed below with reference to the Figures. However, those skilled in the art will readily appreciate that the detailed description given herein with respect to these figures is for explanatory purposes as the systems and methods extend beyond these limited embodiments. For example, it should be appreciated that those skilled in the art will, in light of the teachings of the present description, recognize a multiplicity of alternate and suitable approaches, depending upon the needs of the particular application, to implement the functionality of any given detail described herein, beyond the particular implementation choices in the following embodiments described and shown. That is, there are numerous modifications and variations that are too numerous to be listed but that all fit within the scope of the present description. Also, singular words should be read as plural and vice versa and masculine as feminine and vice versa, where appropriate, and alternative embodiments do not necessarily imply that the two are mutually exclusive.
It is to be further understood that the present description is not limited to the particular methodology, compounds, materials, manufacturing techniques, uses, and applications, described herein, as these may vary. It is also to be understood that the terminology used herein is used for the purpose of describing particular embodiments only, and is not intended to limit the scope of the present systems and methods. It must be noted that as used herein and in the appended claims (in this application, or any derived applications thereof), the singular forms “a,” “an,” and “the” include the plural reference unless the context clearly dictates otherwise. Thus, for example, a reference to “an element” is a reference to one or more elements and includes equivalents thereof known to those skilled in the art. All conjunctions used are to be understood in the most inclusive sense possible. Thus, the word “or” should be understood as having the definition of a logical “or” rather than that of a logical “exclusive or” unless the context clearly necessitates otherwise. Structures described herein are to be understood also to refer to functional equivalents of such structures. Language that may be construed to express approximation should be so understood unless the context clearly dictates otherwise.
Unless defined otherwise, all technical and scientific terms used herein have the same meanings as commonly understood by one of ordinary skill in the art to which this description belongs. Preferred methods, techniques, devices, and materials are described, although any methods, techniques, devices, or materials similar or equivalent to those described herein may be used in the practice or testing of the present systems and methods. Structures described herein are to be understood also to refer to functional equivalents of such structures. The present systems and methods will now be described in detail with reference to embodiments thereof as illustrated in the accompanying drawings.
From reading the present disclosure, other variations and modifications will be apparent to persons skilled in the art. Such variations and modifications may involve equivalent and other features which are already known in the art, and which may be used instead of or in addition to features already described herein.
Although Claims may be formulated in this Application or of any further Application derived therefrom, to particular combinations of features, it should be understood that the scope of the disclosure also includes any novel feature or any novel combination of features disclosed herein either explicitly or implicitly or any generalization thereof, whether or not it relates to the same systems or methods as presently claimed in any Claim and whether or not it mitigates any or all of the same technical problems as do the present systems and methods.
Features which are described in the context of separate embodiments may also be provided in combination in a single embodiment. Conversely, various features which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable sub-combination. The Applicants hereby give notice that new claims may be formulated to such features and/or combinations of such features during the prosecution of the present Application or of any further Application derived therefrom.
This application claims the benefit under 35 U.S.C. Section 119(e) of U.S. Provisional Application No. 63/067,569 filed on Aug. 19, 2020 by Eric W. McFarland and entitled “CHEMICAL REACTION AND CONVERSION IN THERMALLY HETEROGENEOUS AND NON-STEADY-STATE CHEMICAL REACTORS”, and U.S. Provisional Application No. 63/106,031 filed on Oct. 27, 2020 by Eric W. McFarland and entitled “CHEMICAL PROCESSES AND REACTOR SYSTEMS FOR HIGH TEMPERATURE NON-ISOTHERMAL REACTORS” (attorney docket 30794.0788USP1) both of which applications are incorporated herein by reference in their entirety for all purposes.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US21/46627 | 8/19/2021 | WO |
| Number | Date | Country | |
|---|---|---|---|
| 63106031 | Oct 2020 | US | |
| 63067569 | Aug 2020 | US |
