Environmental barrier coatings for chemical processes and systems

Abstract

A chemical processing unit includes a ceramic-containing structure; and a coating layer in contact with at least a portion of the ceramic-containing structure and capable of reducing or preventing degradation of the ceramic-containing structure by a process fluid at a processing temperature, wherein the process fluid includes two or more of hydrogen gas, oxygen gas, carbon monoxide gas, carbon dioxide gas, water vapor, and a gaseous hydrocarbon; wherein the coating layer includes one or more coating materials following at least one of the chemical formulas: MxOz, MxSiyOz, and MxPyOz, wherein M is a metal, x ranges from 1 to 4, y ranges from 1 to 4, and z ranges from 1 to 7.

Description

ENVIRONMENTAL BARRIER COATINGS FOR CHEMICAL PROCESSES AND SYSTEMSCROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of and priority to U.S. Provisional Application 63 / 561,861, titled “ENVIRONMENTAL BARRIER COATINGS”, filed March 6, 2024, the contents of which are incorporated by reference herein.STATEMENT OF GOVERNMENT RIGHTS

[0002] This invention was made with government support under DE-AR0001601 and DE-EE0009806 awarded by the U.S. Department of Energy. The government has certain rights in the invention.TECHNICAL FIELD

[0003] The subject matter disclosed herein relates to the fields of chemical production and energy conversion generally, and more particularly to environmental barrier coatings for chemical processes and systems.BACKGROUND

[0004] Recently, new methods have been developed for designing new materials, including alloys and ceramic metal composites (CMCs), with enhanced properties to endure various applications. These alloys and ceramic materials can be used in industries such as the automotive, aerospace, and chemical industries. For example, ceramics are highly acclaimed in various chemical reactor-based applications due to excellent mechanical properties. However, long term material protection remains a significant limitation, particularly in extreme environments. For example, silicon carbide ceramic materials are known for exemplary mechanical characteristics but suffer from corrosion, degradation, and damage in extreme temperature and / or chemical environments. Accordingly, the present disclosure provides environmental barrier coatings and coating application methods for effectively shielding alloys and ceramics from chemical reactions, extreme temperatures, and / or environmental degradation. Therefore, these environmental barrier coatings can extend the lifetime of equipment used in harsh environments.SUMMARY

[0005] According to one aspect, a chemical processing unit includes a ceramiccontaining structure; and a coating layer in contact with at least a portion of the ceramiccontaining structure and capable of reducing or preventing degradation of the ceramiccontaining structure by a process fluid at a processing temperature, wherein the process fluid includes two or more of hydrogen gas, oxygen gas, carbon monoxide gas, carbon dioxide gas, water vapor, and a gaseous hydrocarbon; wherein the coating layer includes one or more coating materials following at least one of the chemical formulas: MXOZ, MxSiyOz, and MxPyOz, wherein M is a metal, x ranges from 1 to 4, y ranges from 1 to 4, and z ranges from 1 to 7.

[0006] According to another aspect, a chemical reactor includes a ceramic-containing structure; and a coating layer in contact with at least a portion of the ceramic-containing structure, the coating layer including one or more coating materials following at least one of the chemical formulas: MXOZ, MxSiyOz, and MxPyOz, wherein M is a metal, x ranges from 1 to 4, y ranges from 1 to 4, and z ranges from 1 to 7, wherein the chemical reactor is capable of performing a chemical reaction where a process fluid is present in at least a portion of the chemical reactor, the process fluid including two or more of hydrogen gas, oxygen gas, carbon monoxide gas, carbon dioxide gas, water vapor, and a gaseous hydrocarbon.

[0007] According to another aspect, a method for performing a chemical reaction includes introducing process fluids into a chemical processing unit, the process fluids including two or more of hydrogen gas, oxygen gas, carbon monoxide gas, carbon dioxide gas, water vapor, and a gaseous hydrocarbon, wherein the chemical processing unit includes: a ceramic-containing structure; and a coating layer in contact with at least a portion of the ceramic-containing structure, wherein the coating layer includes one or more coating materials following at least one of the chemical formulas: MXOZ, MxSiyOz, and MxPyOz, wherein M is a metal, x ranges from 1 to 4, y ranges from 1 to 4, and z ranges from 1 to 7.

[0008] According to another aspect, a method of applying a coating to a ceramiccontaining structure to form a barrier layer includes (a) forming a coating mixture by mixing one or more carriers with one or more coating materials following at least one of the chemical formulas: MXOZ, MxSiyOz, and MxPyOz, wherein M is a metal, x ranges from 1 to 4, y ranges from 1 to 4, and z ranges from 1 to 7; (b) contacting the coating mixture with at least aportion of a ceramic-containing structure; (c) treating the coating mixture to form a coating layer; (d) optionally repeating step (b); and (e) optionally repeating step (c).BRIEF DESCRIPTION OF DRAWINGS

[0009] This written disclosure describes illustrative embodiments that are non-limiting and non-exhaustive. Reference is made to illustrative embodiments that are depicted in the figures, in which:

[0010] FIG. 1A illustrates a cross-sectional view of a ceramic-containing structure coated with a coating layer of the present disclosure, according to some embodiments.

[0011] FIG. IB illustrates a cross-sectional view of a ceramic-containing structure coated with a coating layer of the present disclosure, according to some embodiments.

[0012] FIG. 2A illustrates ceramic chemical reactor 200, according to some embodiments.

[0013] FIG. 2B illustrates method 280 for performing a chemical reaction, according to some embodiments.

[0014] FIG. 3 illustrates method 300 for applying a coating to a ceramic-containing structure, according to some embodiments.DETAILED DESCRIPTION

[0015] Embodiments of the present disclosure describe novel coating compositions and coating application methods for ceramic-containing materials, such as ceramic-containing structures used for chemical processing units (e.g., chemical reactors, heat exchangers). For example, these coatings can be utilized in chemical reactors suitable for water-gas shift cycles, steam hydrocarbon reforming, and dry hydrocarbon reforming chemistries. Ceramics are highly acclaimed in various fields due to excellent mechanical properties. Specifically, ceramics can be utilized in chemical processing applications. However, material protection of ceramic-containing materials in chemical processing units remains a significant limitation, particularly in extreme environments. For example, water vapor and other process fluids in chemical processing applications can degrade ceramic materials at high temperatures, including depleting the material, removing the coating, and altering properties. Accordingly, there exists a need for improving the mechanical properties and chemical corrosion resistance of chemical processing units. Examples of chemical processing units include reactors,separators, and heat exchangers. Chemical processing units can include at least a portion of a chemical reactor, at least a portion of a separator, or at least a portion of a heat exchanger. Heat exchangers can be utilized to exchange heat between fluid streams, such as fluid streams including one or more process fluids of the present disclosure. Examples of types of heat exchangers include shell and tube heat exchangers, plate heat exchangers, and spiral heat exchangers. Chemical processing units can include one or more systems (e.g., chemical reactor) useful for producing syngas and / or liquid fuels.

[0016] Coating compositions of the present disclosure can be used as environmental barrier coatings (EBC) for alloys and ceramic-containing materials. Examples of environmental barrier coatings include emissivity coatings, corrosion barrier coatings (CBC), and thermal barrier coatings (TBC). These environmental barrier coatings can create significant advantages for structural components, especially components functioning in extreme temperatures and corrosive environments. In the case of ceramic materials, these coatings can enhance the ability of the ceramic materials to withstand harsh conditions.

[0017] Coating compositions of the present disclosure generally include metal silicates, metal di silicates, metal oxides, and metal phosphates. Coating compositions of the present disclosure can form a coating layer. These coating compositions can include one or more materials following at least one of the chemical formulas: (1) MXOZ, (2) MxSiyOz, and (3) MxPyOz, where M includes a metal, O = Oxygen, Si = Silicon, and P = Phosphorous. In one example, x ranges from 1 to 4, y ranges from 1 to 4, and z ranges from 1 to 7. In another example, x ranges from 1 to 2, y ranges from 1 to 2, and z ranges from 3 to 7. For example, x can range from 1 to 4, y ranges from 1 to 4, and z is either 3, 4, or 7. The values of x, y, and z may be selected based on the charge potential of the material. In yet another example, the coating compositions may include one or more materials following at least one of the chemical formulas: NfcSi?!)?, M2O3, and MPO4.

[0018] The metal can include at least one of Zirconium and Aluminum. In one example, the metal is selected from a rare-earth metal, Zirconium, and Aluminum. In another example, the metal includes at least one rare-earth metal. Accordingly, the coating composition may include one or more rare-earth materials following at least one of the chemical formulas: MXOZ, MxSiyOz, and MxPyOz, wherein M is a rare-earth metal, and wherein x ranges from 1 to 4, y ranges from 1 to 4, and z ranges from 1 to 7. The rare-earth metal can include at least one of Scandium, Yttrium, Lanthanum, Cerium, Praseodymium, Neodymium, Promethium,Samarium, Europium, Gadolinium, Terbium, Dysprosium, Holmium, Erbium, Thulium, Ytterbium, and Lutetium. The rare-earth metal can include two or more of Scandium, Yttrium, Lanthanum, Cerium, Praseodymium, Neodymium, Promethium, Samarium, Europium, Gadolinium, Terbium, Dysprosium, Holmium, Erbium, Thulium, Ytterbium, and Lutetium. An example of a representative chemical formula for formula (1) includes Y2O3. Examples of representative chemical formulas for formula (2) include Y2SiOs, Y2Si2O?, YbSiOs, Yb2Si2O?, and Sc2SiOs. Examples of representative chemical formulas for formula (3) include YPO4, YbPCU, and ErPCU. Coating compositions of the present disclosure may include TbSi2.

[0019] The coating composition can be in the form of coating layer in contact with at least a portion of a ceramic-containing structure. Therefore, this coating layer can act as a barrier layer to harsh chemical conditions, such as process fluids at high temperatures. These high temperatures may be necessary to initiate or maintain a chemical reaction. Further, it may be desirable to select a process temperature that increases the life of a catalyst used for the chemical reaction, such as a process temperature for decreasing the rate of catalyst degradation or catalyst coking. Additionally, or alternatively, the process temperature is selected to increase desirable product yield. Unfortunately, the selected process temperatures beneficial for the catalyst properties or reaction yield, in combination with process fluids used for, or generated by, the reaction, can be detrimental to the ceramic-containing structures. For example, these process temperatures of the present disclosure, in combination with process fluids of the present disclosure, can degrade (e.g., chemically degrade) at least a portion of a ceramic-containing structure at typical operating conditions. The coating layers of the present disclosure reduce or prevent this degradation, increasing the lifetime of the unit.

[0020] In one example, the ceramic-containing structure includes at least one of silicon carbide, silicon nitride, quartz, mullite, aluminum oxide, zirconia, a reinforced carbon composite, cordierite, and aluminum nitride. In another example, the ceramic-containing structure includes two or more of silicon carbide, silicon nitride, quartz, mullite, aluminum oxide, zirconia, a reinforced carbon composite, cordierite, and aluminum nitride. In yet another example, the ceramic-containing structure includes silicon carbide.

[0021] Ceramics are highly acclaimed in various fields due to excellent mechanical properties. Specifically, ceramics can be utilized in chemical processing applications. However, and as discussed, material protection remains a significant limitation, particularlyin extreme environments. Coating layer(s) of the present disclosure are generally in contact with at least a portion of the ceramic-containing structure. The coating layer is capable of reducing or preventing degradation of the ceramic-containing structure by a process fluid at a processing temperature, wherein the process fluid includes one or more of hydrogen gas, carbon monoxide gas, oxygen, carbon dioxide gas, water vapor, and a gaseous hydrocarbon (e.g., CaHb, where a is 1 or greater, and b is 1 or greater). Degradation generally includes at least one of physical degradation, chemical degradation, and thermal degradation. Physical degradation includes changes in physical properties, without substantially altering chemical composition, such as from thermal effects. Chemical degradation includes one or more changes to the chemical composition of a material, such as by interactions / reactions with species such as oxygen, water vapor, carbon monoxide, carbon dioxide, gaseous hydrocarbons, or hydrogen. Chemical degradation can be caused by at least one of oxidation and reduction. Chemical degradation can include corrosion. Thermal degradation occurs when a material is exposed to high process temperatures, leading to a change in physical and / or chemical properties. The process fluids and process temperatures utilized to efficiently produce product chemicals, such as syngas or hydrocarbons, can conventionally promote degradation of structures used in chemical processing units. This conventional degradation decreases unit lifetime.

[0022] In one example, the process fluid includes two or more of: hydrogen gas, carbon monoxide gas, oxygen, carbon dioxide gas, water vapor, and a gaseous hydrocarbon. In another example, the process fluid includes three or more of: hydrogen gas, carbon monoxide gas, oxygen, carbon dioxide gas, water vapor, and a gaseous hydrocarbon. In another example, the process fluid includes hydrogen gas and at least one of: carbon monoxide gas, oxygen, carbon dioxide gas, water vapor, and a gaseous hydrocarbon. In another example, the process fluid includes hydrogen gas and carbon dioxide gas.

[0023] The process fluid can include water vapor. The coating layer can reduce or prevent degradation of the ceramic-containing structure by water vapor at a process temperature. The process fluid can include hydrogen gas. The coating layer can reduce or prevent degradation (such as degradation by reduction from hydrogen presence) to the ceramic-containing structure by hydrogen at a process temperature. In another example, the process fluid includes carbon dioxide gas. The coating layer can reduce or prevent degradation (such as degradation by oxidation from carbon dioxide presence) to the ceramic-containing structure by carbon dioxide at a process temperature. In another example, the process fluid includes carbon monoxide. Importantly, the coating layer exhibits resilience to carbon monoxide at a process temperature.

[0024] The process temperature can be a temperature above 300 °C. In one example, process temperature is a temperature above 400 °C. In another example, the process temperature is a temperature between 500 °C and 2000 °C. In yet another example, the process temperature is a temperature between 500 °C and 1200 °C. In one non-limiting example, a process temperature of between 500 °C and 1200 °C can promote at least one of the process fluids herein to at least partially degrade (e.g., physically degrade, reduce, and / or oxidize) the ceramic-containing structure. The coating layer efficiently reduces or prevents this degradation to the ceramic-containing structure, at least in part by acting as a barrier layer.

[0025] The process temperature can be greater than about 550 °C, about 600 °C, about 650 °C, about 700 °C, about 750 °C, about 800 °C, about 850 °C, or temperatures therebetween. The process temperature can be less than about 1500 °C, about 1200 °C, about 1000 °C, or about 800 °C. In one example, a process pressure for a chemical processing unit can be between about 1 bar and about 40 bar. In another example, a process pressure for a chemical processing unit can be between about 5 bar and about 20 bar. In another example, a process pressure for a chemical processing unit can be between about 1 bar and about 5 bar. The chemical processing unit can be operated at a process pressure above 1 bar, above 2 bar, above 3 bar, above 4 bar, or above 5 bar.

[0026] The metal silicates, metal disilicates, metal oxides, and metal phosphates of the present disclosure can sustain high temperatures, such as temperatures greater than about 1700 °C. Therefore, these metal silicates, metal disilicates, metal oxides, and metal phosphates can reduce or prevent degradation at process temperatures of the present disclosure. These metal silicates, metal disilicates, metal oxides, and metal phosphates can also be rapidly coated on the ceramic-containing structure, promoting an efficient and cost- effective application process. Further, these materials can be desirable since the materials can exhibit high entropy, low oxidant permeability, and high mechanical moduli.

[0027] Rare-earth materials of the present disclosure also have excellent repairability. The specific metal silicate, metal disilicate, metal oxide, or metal phosphate may be selected based on the coefficient of thermal expansion (CTE) of the ceramic-containing structure. Forexample, silicon carbide can exhibit a CTE of about 4*10'6 / °C. For example, the CTE of the one or more materials (following formulas 1, 2, and / or 3) may be within 15% of the CTE of the ceramic-containing structure. In one example, the CTE of the one or more materials (following formulas 1, 2, and / or 3) is within 10% of the CTE of the ceramic-containing structure. The CTE value of the one or more materials (following formulas 1, 2, and / or 3) can be within 10*10'6 / °C of the ceramic-containing structure. In one example, the CTE value of the one or more materials (following formulas 1, 2, and / or 3) is within 7*10'6 / °C of the ceramic-containing structure. A CTE value of within 7*10'6 / °C of the ceramic-containing structure can promote lower thermal stresses and excellent interdiffusion. In one non-limiting example, if the CTE value is not within this range, crazing of the ceramic-containing structure can occur at high temperatures, such as process temperatures of the present disclosure. In another example, the CTE value of the one or more materials (following formulas 1, 2, and / or 3) is within 4.5*10'6 / °C of the ceramic-containing structure. In another example, the CTE value of the one or more materials (following formulas 1, 2, and / or 3) is within 2.5*10'6 / °C of the ceramic-containing structure. Further, the coating layer can provide resistance to high velocity process fluids, such as gases and steam, with velocities between 5m / s and 120 m / s.

[0028] The one or more materials (following formulas 1, 2, and / or 3) can exhibit a thermal conductivity of greater than 1 W / m*K. The thermal conductivity is the heat transferred through the material per unit area and per unit temperature gradient. In one example, the one or more materials (following formulas 1, 2, and / or 3) can exhibit a thermal conductivity of greater than 3 W / m*K. In another example, the one or more materials (following formulas 1, 2, and / or 3) can exhibit a thermal conductivity of greater than 9 W / m*K. For example, in reactors at least partially filled with catalysts and used for exothermic reactions, coating layers as discussed in the present disclosure with thermal conductivities of the present disclosure can promote uniform temperature distribution and improved heat efficiencies along the catalysts, while staying inert. In the case of a lower thermal conductivity, the reactors or chemical processing units could experience uneven heat spots due to the nature of the reaction.

[0029] The one or more materials (following formulas 1, 2, and / or 3) can be present in a coating composition, such as in the form of a fluid mixture. In one example, the volume percentage of the one or more materials (following formulas 1, 2, and / or 3) in the coatingcomposition ranges from about 1 vol% to about 63 vol%. In another example, the volume percentage of the one or more materials (following formulas 1, 2, and / or 3) in the coating composition ranges from about 5 vol% to about 30 vol%. In another example, the volume percentage of the one or more materials (following formulas 1, 2, and / or 3) in the coating composition ranges from about 10 vol% to about 20 vol%.

[0030] Coating compositions (e.g., for application on the ceramic-containing structure) may include one or more organic polymers. The one or more organic polymers may include a preceramic polymer or a precursor metal or a metal organic framework. Examples of preceramic polymers include polycarbosilanes and polysiloxanes. These preceramic polymers can form polymer derived ceramics, such as silicon carbide, silicon oxycarbides, and silicon nitride. In one example, the volume percentage of the one or more organic polymers in the coating composition ranges from about 50 vol% to 90 vol%. In another example, the volume percentage of the one or more organic polymers in the coating composition ranges from about 70 vol% to 90 vol%. In yet another example, the volume percentage of the one or more organic polymers in the coating composition ranges from about 80 vol% to 90 vol%.

[0031] Coating compositions of the present disclosure may be applied to the ceramiccontaining structure using various techniques. For example, coating compositions may be applied to the ceramic-containing structure using polymer infiltration and pyrolysis (PIP), sol-gel, electroplating / electrodeposition, metalliding, cladding, spray coating, and / or dip coating. Spray coating may utilize lasers, plasma, and / or various heat sources to coat the ceramic-containing structure. These methods may be utilized to apply one or more layers of the coating composition on / in the ceramic-containing structure. For example, and in the case of a reverse water gas shift reactor, examples of ceramic-containing structures include silicon carbide, silicon nitride, aluminum nitride, quartz, and fiber reinforced composites thereof. The ceramic-containing structure may be formed by pressing, tube drawing, powder metallurgy, or additive manufacturing.

[0032] Coating compositions of the present disclosure can be applied to a ceramiccontaining structure (e.g., a ceramic structure) to form a coating layer. These coating layers can protect the ceramic-containing structure from extreme environmental conditions. For example, these coating layers and methods of applying the coatings enable the production of structural components with exceptional barrier properties against high temperatures, corrosion, and emissivity. These coating layers can be used in applications such as chemicalreactors. For example, these coating layers are useful in at least a portion of a chemical reactor. In one example, the coating layer is utilized in at least a portion of a RWGS reactor (e.g., for performing the RWGS reaction), a dry methane reforming reactor (e.g., for performing dry methane reforming), a steam methane reforming reactor (e.g., for performing steam methane reforming), a water gas shift reactor (e.g., for performing the water gas shift reaction), an autothermal reformer (e.g., for performing autothermal reforming), a Fischer- Tropsch reactor, or a methanol reactor.

[0033] Equation 1 represents the RWGS reaction which involves the reduction of carbon dioxide and the oxidation of hydrogen to form carbon monoxide and water:CO2+ H2CO + H2O (Equation 1)

[0034] Equation 2 represents a reaction for dry methane reforming. Dry methane reforming is an efficient method to produce syngas.CO2+ CH4 2CO + 2H2(Equation 2)

[0035] Equation 3 represents a steam methane reforming reaction. Steam methane reforming can be used to produce carbon monoxide and hydrogen.CH4+ H2O CO + 3H2(Equation 3)Carbon monoxide is a versatile feedstock useful in the production of a wide range of chemical products. For example, carbon monoxide can be hydrogenated to form various liquid fuels (e.g., diesel, gasoline, and alcohols).

[0036] Equation 4 represents a water gas shift reaction. The water gas shift reaction describes the reaction of carbon monoxide and water vapor to form carbon dioxide and hydrogen.CO + H2O CO2+ H2(Equation 4)

[0037] Autothermal reforming (ATR) is a process that combines partial oxidation and steam reforming to convert hydrocarbons, such as natural gas, into syngas (a mixture of hydrogen and carbon monoxide). Autothermal reforming can utilize oxygen and at least one of carbon dioxide and steam to produce hydrogen and carbon monoxide.

[0038] The Fischer-Tropsch reaction is a catalytic chemical reaction for converting carbon monoxide and hydrogen into hydrocarbons of various molecular weights. Depending on the catalyst and the temperature, differing molecular weight hydrocarbons may be produced. An example equation for a reaction in the Fischer-Tropsch process is shown belowas Equation 5, where n = 1 or more. Another example reaction in the Fischer-Tropsch process may be the water gas shift reaction, shown as Equation 6.(2n+l) H2 + n CO — > CnH(2n+2) + n FEO (Equation s) CO + H2O — > H2 + CO2 (Equation 6)The Fischer-Tropsch reaction is highly exothermic. This process may include one or more of reactors, separations units, compressors, heat exchangers, and recycle streams. Reactors utilized for the Fischer-Tropsch process may include fixed bed reactors, fluidized bed reactors, tubular fixed bed reactor, and slurry bed reactors.

[0039] Methanol production also utilizes high pressure syngas and may include one or more of reactors, separations units, compressors, heat exchangers, and recycle streams. In one example, methanol production may utilize one or more of carbon dioxide and carbon monoxide as feed stocks. Catalysts for methanol synthesis may include one or more of copper, zinc oxide, alumina, and magnesia. Methanol production may utilize a reactor such as a fixed bed reactor at high pressure. In another example, methanol production includes a reactor operated at a pressure between 40 bar and 120 bar and a pressure between 200 °C to 400 °C. In another example, methanol production is a very exothermic reaction and follows the general reaction of equation 7 or equation 8 listed below. Products in the methanol production process may include methanol and water.CO + 2H2CH3OH (Equation 7)CO2+ 3H2CH3OH + H2O (Equation 8)

[0040] FIG. 1A illustrates a cross-sectional view of a ceramic-containing structure coated with a coating layer of the present disclosure, according to some embodiments. As shown in FIG. 1A, coating layer 110 is in contact with at least a portion of ceramiccontaining structure 130, and coating layer 110 may conform to the surface structure of ceramic-containing structure 130. As shown in FIG. 1A, there can be an interaction between ceramic-containing structure 130 and coating layer 110. After being adsorbed by the surface, surface diffusion can incorporate the molecules of the coating composition into the lattice of ceramic-containing structure 130. FIG. IB illustrates a cross-sectional view of a ceramiccontaining structure coated with a coating layer of the present disclosure, according to some embodiments. As shown in FIG. IB, an interlayer 120 may be present between coating layer 110 and ceramic-containing structure 130. Interlayer 120 can be a bonding layer between ceramic-containing structure 130 and coating layer 110. In one example, interlayer 120includes Silicon. In another example, interlayer 120 includes a ceramic material. When the coating composition comes in contact with a substrate (e.g., interlayer 120 or ceramiccontaining structure 130), molecules can react with the surface of the substrate. As shown in FIG. IB, there can be an interaction between interlayer 120 and coating layer 110. The coating layer 110 and ceramic-containing structure 130, and optionally interlayer 120, can be utilized in a chemical processing unit. For example, the chemical processing unit can include a chemical reactor or a heat exchanger.

[0041] FIG. 2A illustrates ceramic chemical reactor 200, according to some embodiments. Ceramic chemical reactor 200 is capable of performing at least one of the chemical reactions of the present disclosure. Accordingly, one or more process fluids can be present within at least a portion of ceramic chemical reactor 200. Ceramic chemical reactor 200 may be a heterogeneous catalytic reactor, and ceramic chemical reactor 200 includes ceramic-containing structure 210 and coating layer 220. Ceramic-containing structure 210 includes one or more ceramic-containing structures of the present disclosure. Ceramic chemical reactor 200 may include inlet 250 for one or more inlet gases, outlet 260 for one or more product gases and / or water, and a heat source 270. The one or more inlet gases and one or more product gases and / or water can each include one or more process fluids of the present disclosure. Ceramic chemical reactor 200 can be operated at process temperatures and process pressures of the present disclosure.

[0042] In one example, ceramic chemical reactor 200 is a reverse-water gas shift reactor, where inlet gases include carbon dioxide and hydrogen, and the product gas includes carbon monoxide. Heat source 270 may be an external heat source for applying external heat to ceramic chemical reactor 200. Ceramic chemical reactor 200 generally includes a catalytic material. FIG. 2 A illustrates a simplified geometry of a reactor, and embodiments of the present disclosure include other reactor geometries suitable for chemical reactions, such as the reverse-water gas shift reaction. For example, ceramic chemical reactor 200 can include an internal heating element (not shown) inside the reactor encasement to heat the system. Ceramic chemical reactor 200 can include one or more baffles, fin(s), inlet(s), outlet(s), conduit(s), and / or heat source(s).

[0043] Ceramic-containing structure 210 can be present as a reactor encasement. The reactor encasement can have a length, a width, and a depth, where the length extends from a distal portion of the reactor encasement to a proximal portion of the reactor encasement. Atleast a portion of the reactor encasement defines an internal reaction volume. Alternatively, or additionally, ceramic-containing structure 210 can be present within a portion of ceramic chemical reactor 200, such as present in a reactor baffle, reactor fin, reactor inlet, reactor outlet, feed conduit, or return conduit. The feed conduit and / or return conduit can be surrounded by a reactor encasement. In one example, ceramic-containing structure 210 includes a ceramic material, such as one or more of silicon carbide, silicon nitride, and aluminum nitride. In another example, the ceramic-containing structure 210 includes at least one of silicon carbide, silicon nitride, quartz, mullite, aluminum oxide, zirconia, a reinforced carbon composite, cordierite, and aluminum nitride. As shown, coating layer 220 is in contact with at least a portion of ceramic-containing structure 210. Coating layer 220 may be applied to the ceramic-containing structure 210 using methods of the present disclosure.

[0044] Coating layer 220 is shown in contact with an interior surface of ceramiccontaining structure 210, but coating layer 220 can also be applied to an exterior surface of ceramic-containing structure 210. Coating layer 220 can be present in a portion of ceramic chemical reactor 200 for generating one or more product gases or vapors. Coating layer 220 generally includes metal silicates, metal disilicates, metal oxides, and metal phosphates. Coating layer 220 includes one or more materials following at least one of the chemical formulas: (1) MXOZ, (2) MxSiyOz, and (3) MxPyOz, where M includes a metal, O = Oxygen, Si = Silicon, and P = Phosphorous. In one example, x ranges from 1 to 4, y ranges from 1 to 4, and z ranges from 1 to 7. In another example, x ranges from 1 to 2, y ranges from 1 to 2, and z ranges from 3 to 7. For example, x can range from 1 to 4, y ranges from 1 to 4, and z is either 3, 4, or 7. The values of x, y, and z may be selected based on the charge potential of the material. In yet another example, the coating compositions may include one or more materials following at least one of the chemical formulas: NESi?!)?, M2O3, and MPO4.

[0045] The metal can include at least one of Zirconium and Aluminum. In one example, the metal is selected from a rare-earth metal, Zirconium, and Aluminum. In another example, the metal includes at least one rare-earth metal. Accordingly, the coating composition may include one or more rare-earth materials following at least one of the chemical formulas: MXOZ, MxSiyOz, and MxPyOz, wherein M is a rare-earth metal, and wherein x ranges from 1 to 4, y ranges from 1 to 4, and z ranges from 1 to 7. The rare-earth metal can include at least one of Scandium, Yttrium, Lanthanum, Cerium, Praseodymium, Neodymium, Promethium, Samarium, Europium, Gadolinium, Terbium, Dysprosium, Holmium, Erbium, Thulium,Ytterbium, and Lutetium. The rare-earth metal can include two or more of Scandium, Yttrium, Lanthanum, Cerium, Praseodymium, Neodymium, Promethium, Samarium, Europium, Gadolinium, Terbium, Dysprosium, Holmium, Erbium, Thulium, Ytterbium, and Lutetium. An example of a representative chemical formula for formula (1) includes Y2O3. Examples of representative chemical formulas for formula (2) include Y2SiOs, Y2Si2O?, YbSiOs, Yb2Si2O?, and Sc2SiOs. Examples of representative chemical formulas for formula (3) include YPO4, YbPCU, and ErPCU. Coating compositions of the present disclosure may include TbSi2.

[0046] At least a portion / zone of ceramic chemical reactor 200 may be operated at temperatures above about 500 °C. In one example, at least a portion / zone of ceramic chemical reactor 200 is operated at temperatures above 1000 °C. Importantly, these high temperatures (such as temperatures above about 1000 °C) and gases / vapors used in ceramic chemical reactor 200 may cause degradation and corrosion to ceramic-containing structure 210 if coating layer 220 is not utilized. For example, steam, carbon monoxide, and / or hydrogen can cause issues (e.g., degradation) for reactor walls. Coating layer 220 may act as an environmental barrier layer for ceramic-containing structure 210 to increase temperature and corrosion resistance. Further, coating layer 220 may be thermally conductive to allow heat source 270 to transfer heat to ceramic chemical reactor 200.

[0047] FIG. 2B illustrates method 280 for performing a chemical reaction, according to some embodiments. Method 280 includes at least Step 282.

[0048] Referring to Step 282, process fluids are introduced into a chemical processing unit, the process fluids including two or more of hydrogen gas, carbon monoxide gas, carbon dioxide gas, water vapor, and a gaseous hydrocarbon. The chemical processing unit can include a chemical reactor of the present disclosure. The chemical processing unit can include a catalyst within at least a portion of the chemical processing unit for promoting the chemical reaction. The chemical reaction can the RWGS reaction, dry methane reforming, steam methane reforming, the water gas shift reaction, autothermal reforming, Fischer-Tropsch reaction(s), or a methanol reaction. The chemical reaction can be initiated or performed at a process temperature and process pressure of the present disclosure.

[0049] In one example, the process fluid includes two or more of: hydrogen gas, carbon monoxide gas, oxygen, carbon dioxide gas, water vapor, and a gaseous hydrocarbon. In another example, the process fluid includes three or more of: hydrogen gas, carbon monoxidegas, oxygen, carbon dioxide gas, water vapor, and a gaseous hydrocarbon. In another example, the process fluid includes hydrogen gas and at least one of: carbon monoxide gas, oxygen, carbon dioxide gas, water vapor, and a gaseous hydrocarbon. In another example, the process fluid includes hydrogen gas and carbon dioxide gas. The chemical reaction can be used to produce at least one of hydrogen and carbon monoxide. The process fluid can include oxygen.

[0050] FIG. 3 illustrates method 300 for applying a coating to a ceramic-containing structure to form a barrier layer, according to some embodiments. Method 300 includes one or more of the following steps (with various orders possible):

[0051] At Step 310, a coating mixture is formed by mixing one or more carriers with one or more coating materials following at least one of the chemical formulas: MXOZ, MxSiyOz, and MxPyOz, wherein M is a metal, x ranges from 1 to 4, y ranges from 1 to 4, and z ranges from 1 to 7. Mixing may include contacting and / or infusing / filling the one or more coating materials with the one or more carriers. The one or more carriers may be in the form of a liquid or wax. The one or more coating materials may be in the form of a powder. Accordingly, step 310 may form a suspension.

[0052] The one or more carriers can include one or more organic polymers or precursors thereof. The one or more organic polymers may include a preceramic polymer. Examples of preceramic polymers include polycarbosilanes and polysiloxanes. These preceramic polymers can form polymer derived ceramics, such as silicon carbide, silicon oxycarbides, and silicon nitride. In one example, the one or more organic polymers includes an organic coordination polymer. The organic coordination polymer can include a metal and / or a non-metal. In one example, the volume percentage of the one or more carriers in the coating mixture ranges from about 50 vol% to 90 vol%. In another example, the volume percentage of the one or more carriers in the coating mixture ranges from about 70 vol% to 90 vol%. In yet another example, the volume percentage of the one or more carriers in the coating mixture ranges from about 80 vol% to 90 vol%.

[0053] In one example, the volume percentage of one or more coating materials in the coating mixture ranges from about 2 vol% to about 40 vol%. In another example, the volume percentage of the one or more coating materials in the coating mixture ranges from about 5 vol% to about 25 vol%. In yet another example, the volume percentage of one or more coating materials in the coating mixture ranges from about 10 vol% to about 20 vol%. Forexample, the volume percentage of the one or more coating materials in the coating mixture may be greater than 5 vol%, greater than 10 vol%, or greater than 15 vol%. The one or more coating materials can be present as a powder. In one example, the one or more coating materials include a plurality of particles. For example, the plurality of particles can have an average particle size of between 0.1 pm and 75 pm.

[0054] At Step 320, the coating mixture is contacted with at least a portion of a ceramic-containing structure. Contacting the coating mixture with the ceramic-containing structure is generally sufficient to infiltrate pores of the ceramic-containing structure and / or react the coating mixture with a surface of the ceramic-containing structure. Contacting can include contacting the coating mixture (in a liquid form) with at least a portion of the ceramic-containing structure. In one example, the coating mixture is applied to the ceramiccontaining structure by a spray stream or vapor stream.

[0055] In one example, the coating mixture is applied to form a coated layer with a deposition thickness ranging from about 5 microns to about 200 microns. In another example, the coating mixture is applied to form a coated layer with a deposition thickness ranging from about 25 microns to about 75 microns. Step 320 may include using vacuum (such as up to 0.01 bar, or 0.1 bar), gravity, pressure (such as greater than about 1 bar, or greater than about 10 bar), or capillary action to infiltrate pores of the ceramic-containing structure with the coating mixture.

[0056] Examples of ceramic-containing structures include silicon carbide, silicon nitride, and aluminum nitride. Ceramic-containing structures may include silicon carbide (SiC) with a green density of approximately 43% - 59%, silicon nitride with a green density of approximately 69%, boron carbide with a green density of approximately 60%, and aluminum oxide with a green density of approximately 63.5%. The pores of the ceramiccontaining structure may vary based on the selection of the particle shape and size of the material used to produce the structure. Further, pore size may vary based on manufacturing processes such as the packing density of particles during the manufacturing process. Pore morphology may also vary based on the shape and surface characteristics of the particle. Smooth particles may have regular and controllable pore morphology, whereas rough particles may have irregular pore morphologies. The morphology of the pore may assist in selecting the preceramic polymer used to infiltrate the pore.

[0057] At Step 330, the coating mixture is treated to form a coating layer. For example, treating can include post-processing to dry or cure the coating mixture to form the coating layer. In one example, treating the coating mixture to form the coating layer includes pyrolysis. In another example, treating the coating mixture to form the coating layer includes irradiation curing, using sufficient irradiation energy to at least partially cure (e.g., secure) the coating mixture to the ceramic-containing structure.

[0058] Step 330 can include pyrolysis or thermal processing of the coating mixture to form the coating layer. For example, pyrolysis may utilize one or more inert gases with a velocity above 10 seem. In one example, the coating mixture is pyrolyzed at a temperature ranging from about 400 °C to about 1000 °C. In another example, the coating mixture is pyrolyzed at a temperature above about 400 °C. In yet another example, the coating mixture is pyrolyzed at a temperature ranging from about 600 °C to about 1000 °C. In one example, coating and pyrolyzing the coating mixture on the ceramic-containing structure includes infiltrating pores of the ceramic-containing structure and increasing the density of the ceramic-containing structure. After adsorbing on the surface of the ceramic-containing structure, molecules in the coating mixture can be incorporated into the ceramic-containing structure lattice by surface diffusion using high temperatures. Additionally, the MXOZ, MxSiyOz, and / or MxPyOzmaterial can remain on the surface of the ceramic-containing structure after the pyrolysis process.

[0059] At Step 340, Step 320 is optionally repeated until desired thickness is obtained. For example, the coating mixture may be contacted with the ceramic-containing structure and / or the previously pyrolyzed coating layer. If Step 320 is repeated, the one or more carriers and / or one or more coating materials may be changed from the initial materials used. The ratio of the one or more carriers and / or one or more coating materials in the coating mixture may be changed in each layer / coating application. Step 320 may be repeated one or more times. Accordingly, the number of coatings can increase the total coating layer thickness. At Step 350, Step 330 is optionally repeated until desired thickness is obtained. Step 330 may be repeated one or more times. The coating layer thickness may be tuned by repeating Step 320 and Step 330 multiple times. In one example, Step 320 and Step 330 are each completed one to five times. In another example, Step 320 and Step 330 are each completed one to three times. The thickness of the coating layer may range from about 5microns to about 25 microns. In one example, the thickness of the coating layer ranges from about 15 microns to about 50 microns.

[0060] Importantly, method 300 may be used to create a protective barrier layer and address existing voids in ceramic materials. For example, these voids can undermine the integrity and performance of the ceramic materials. Accordingly, the barrier layer may be applied during the densification process. By utilizing the unique mixture of one or more carriers and one or more coating materials of the present disclosure, method 300 ensures that the voids are effectively filled, resulting in a more robust and homogenous barrier layer. Further, method 300 forms a barrier layer coating to enhance the thermal properties and corrosion resistance of ceramics in harsh conditions.Discussion of Possible Embodiments

[0061] Clause 1. A chemical processing unit, the chemical processing unit including a ceramic-containing structure; and a coating layer in contact with at least a portion of the ceramic-containing structure and capable of reducing or preventing degradation of the ceramic-containing structure by a process fluid at a processing temperature, wherein the process fluid includes two or more of hydrogen gas, oxygen gas, carbon monoxide gas, carbon dioxide gas, water vapor, and a gaseous hydrocarbon; wherein the coating layer includes one or more coating materials following at least one of the chemical formulas: Mx0z, MxSiyOz, and MxPyOz, wherein M is a metal, x ranges from 1 to 4, y ranges from 1 to 4, and z ranges from 1 to 7.

[0062] The chemical processing unit of the preceding paragraph can optionally include, additionally and / or alternatively any one or more of the following features, configurations and / or additional components.

[0063] Clause 2. The chemical processing unit of clause 1, wherein the metal is Zirconium or Aluminum.

[0064] Clause 3. The chemical processing unit of clause 1, wherein the metal is a rare- earth metal including at least one of Scandium, Yttrium, Lanthanum, Cerium, Praseodymium, Neodymium, Promethium, Samarium, Europium, Gadolinium, Terbium, Dysprosium, Holmium, Erbium, Thulium, Ytterbium, and Lutetium.

[0065] Clause 4. The chemical processing unit of any one of clauses 1-3, wherein x ranges from 1 to 4, y ranges from 1 to 4, and z is either 3, 4, or 7.

[0066] Clause 5. The chemical processing unit of clause 1, wherein the one or more coating materials are selected from Y2SiOs, Y2Si2O?, YPO4, Y2O3, YbSiOs, Yb2Si2O?, YbPO4, TbSi2, Sc2SiO5, and ErPO4.

[0067] Clause 6. The chemical processing unit of any one of clauses 1-5, wherein the process fluid includes hydrogen and at least one of carbon monoxide gas, carbon dioxide gas, water vapor, and a gaseous hydrocarbon; and wherein the process fluid is present within at least a portion of the chemical processing unit.

[0068] Clause 7. The chemical processing unit of any one of clauses 1-6, wherein the processing temperature is between 500 °C and 1200 °C.

[0069] Clause 8. The chemical processing unit of any one of clauses 1-7, wherein a difference in a first coefficient of thermal expansion of the ceramic-containing structure and a second coefficient of thermal expansion of the coating layer is less than 7 10'6 / °C.

[0070] Clause 9. The chemical processing unit of any one of clauses 1-8, wherein the coating layer exhibits an average thermal conductivity of greater than 1 W / m*K.

[0071] Clause 10. The chemical processing unit of any one of clauses 1-9, wherein the chemical processing unit is a chemical reactor or a heat exchanger.

[0072] Clause 11. The chemical processing unit of any one of clauses 1-9, wherein the chemical processing unit is a water gas shift reactor, a reverse-water gas shift reactor, a dry methane reforming reactor, a steam methane reforming reactor, or an autothermal reformer.

[0073] Clause 12. The chemical processing unit of any one of clauses 1-11, wherein the ceramic-containing structure includes at least one of silicon carbide, silicon nitride, quartz, mullite, aluminum oxide, zirconia, a reinforced carbon composite, cordierite, and aluminum nitride.

[0074] Clause 13. The chemical processing unit of any one of clauses 1-12, including at least one inlet for introducing at least one of hydrogen gas, carbon monoxide gas, carbon dioxide gas, water vapor, and a gaseous hydrocarbon into the chemical processing unit.

[0075] Clause 14. A chemical reactor, the chemical reactor including a ceramiccontaining structure; and a coating layer in contact with at least a portion of the ceramiccontaining structure, the coating layer including one or more coating materials following at least one of the chemical formulas: MXOZ, MxSiyOz, and MxPyOz, wherein M is a metal, x ranges from 1 to 4, y ranges from 1 to 4, and z ranges from 1 to 7, wherein the chemical reactor is capable of performing a chemical reaction where a process fluid is present in atleast a portion of the chemical reactor, the process fluid including two or more of hydrogen gas, oxygen gas, carbon monoxide gas, carbon dioxide gas, water vapor, and a gaseous hydrocarbon.

[0076] The chemical reactor of the preceding paragraph can optionally include, additionally and / or alternatively any one or more of the following features, configurations and / or additional components.

[0077] Clause 15. The chemical reactor of clause 14, wherein the metal is Zirconium or Aluminum.

[0078] Clause 16. The chemical reactor of clause 14, wherein the metal is a rare-earth metal including at least one of Scandium, Yttrium, Lanthanum, Cerium, Praseodymium, Neodymium, Promethium, Samarium, Europium, Gadolinium, Terbium, Dysprosium, Holmium, Erbium, Thulium, Ytterbium, and Lutetium.

[0079] Clause 17. The chemical reactor of any one of clauses 14-16, wherein x ranges from 1 to 4, y ranges from 1 to 4, and z is either 3, 4, or 7.

[0080] Clause 18. The chemical reactor of clause 14, wherein the one or more coating materials are selected from Y2SiOs, Y2Si2O?, YPO4, Y2O3, YbSiOs, Yb2Si2O?, YbPCU, TbSi2, Sc2SiOs, and ErPCU.

[0081] Clause 19. The chemical reactor of any one of clauses 14-18, wherein the chemical reactor is a water gas shift reactor, a reverse-water gas shift reactor, a dry methane reforming reactor, a steam methane reforming reactor, or an autothermal reformer.

[0082] Clause 20. The chemical reactor of any one of clauses 14-19, wherein the chemical reaction is performed at a process temperature of at least 500 °C.

[0083] Clause 21. The chemical reactor of any one of clauses 14-20, wherein the ceramic-containing structure includes at least one of silicon carbide, silicon nitride, quartz, mullite, aluminum oxide, zirconia, a reinforced carbon composite, cordierite, and aluminum nitride.

[0084] Clause 22. The chemical reactor of any one of clauses 14-21, wherein the ceramic-containing structure includes silicon carbide.

[0085] Clause 23. A method for performing a chemical reaction, the method including introducing process fluids into a chemical processing unit, the process fluids including two or more of hydrogen gas, oxygen gas, carbon monoxide gas, carbon dioxide gas, water vapor, and a gaseous hydrocarbon, wherein the chemical processing unit includes: a ceramic-containing structure; and a coating layer in contact with at least a portion of the ceramiccontaining structure, wherein the coating layer includes one or more coating materials following at least one of the chemical formulas: MXOZ, MxSiyOz, and MxPyOz, wherein M is a metal, x ranges from 1 to 4, y ranges from 1 to 4, and z ranges from 1 to 7.

[0086] The method of the preceding paragraph can optionally include, additionally and / or alternatively any one or more of the following features, configurations and / or additional components.

[0087] Clause 24. The method of clause 23, wherein the process fluids include hydrogen gas and at least one of carbon monoxide gas, carbon dioxide gas, water vapor, and a gaseous hydrocarbon.

[0088] Clause 25. The method of clause 23, wherein the chemical reaction is selected from a water gas shift reaction, a reverse-water gas shift reaction, dry methane reforming, steam methane reforming, and autothermal reforming.

[0089] Clause 26. The method of any one of clauses 23-25, wherein the chemical reaction is performed at a process temperature of at least 500 °C.

[0090] Clause 27. The method of any one of clauses 23-26, wherein the chemical reaction is performed at a process temperature ranging from about 500 °C to about 1200 °C.

[0091] Clause 28. The method of any one of clauses 23-27, wherein the metal is Zirconium or Aluminum.

[0092] Clause 29. The method of any one of clauses 23-27, wherein the metal is a rare- earth metal including at least one of Scandium, Yttrium, Lanthanum, Cerium, Praseodymium, Neodymium, Promethium, Samarium, Europium, Gadolinium, Terbium, Dysprosium, Holmium, Erbium, Thulium, Ytterbium, and Lutetium.

[0093] Clause 30. The method of any one of clauses 23-29, wherein x ranges from 1 to 4, y ranges from 1 to 4, and z is either 3, 4, or 7.

[0094] Clause 31. The method of clause 23, wherein the one or more coating materials are selected from Y2SiO5, Y2Si2O7, YPO4, Y2O3, YbSiOs, Yb2Si2O7, YbPO4, TbSi2, Sc2SiO5, and ErPO4.

[0095] Clause 32. A method of applying a coating to a ceramic-containing structure to form a barrier layer, the method including (a) forming a coating mixture by mixing one or more carriers with one or more coating materials following at least one of the chemical formulas: MXOZ, MxSiyOz, and MxPyOz, wherein M is a metal, x ranges from 1 to 4, y rangesfrom 1 to 4, and z ranges from 1 to 7; (b) contacting the coating mixture with at least a portion of a ceramic-containing structure; (c) treating the coating mixture to form a coating layer; (d) optionally repeating step (b); and (e) optionally repeating step (c).

[0096] The method of the preceding paragraph can optionally include, additionally and / or alternatively any one or more of the following features, configurations and / or additional components.

[0097] Clause 33. The method of clause 32, wherein the one or more carriers includes at least one of an organic polymer, an organic polymer precursor, and an organic coordination polymer.

[0098] Clause 34. The method of clause 33, wherein the organic polymer includes a polycarbosilane.

[0099] Clause 35. The method of any one of clauses 32-34, wherein the metal is Zirconium or Aluminum.

[0100] Clause 36. The method of any one of clauses 32-34, wherein the metal is a rare- earth metal including at least one of Scandium, Yttrium, Lanthanum, Cerium, Praseodymium, Neodymium, Promethium, Samarium, Europium, Gadolinium, Terbium, Dysprosium, Holmium, Erbium, Thulium, Ytterbium, and Lutetium.

[0101] Clause 37. The method of any one of clauses 32-36, wherein x ranges from 1 to 4, y ranges from 1 to 4, and z is either 3, 4, or 7.

[0102] Clause 38. The method of any one of clauses 32-37, wherein a volume percentage of the one or more coating materials in the coating mixture ranges from about 5 vol% to about 40 vol%.

[0103] Clause 39. The method of any one of clauses 32-38, wherein treating the coating mixture includes pyrolysis or irradiation curing.

[0104] Clause 40. The method of any one of clauses 32-39, wherein contacting the coating mixture with at least a portion of the ceramic-containing structure forms a layer with a thickness ranging from about 5 microns to about 200 microns.

[0105] While the disclosure has been described with reference to an exemplary embodiment s), it will be understood by those skilled in the art that various changes may be made, and equivalents may be substituted for elements thereof without departing from the scope of the embodiment(s). In addition, many modifications may be made to adapt a particular situation or material to the teachings of the embodiment(s) without departing fromthe essential scope thereof. Therefore, it is intended that the disclosure is not limited to the disclosed embodiment(s), but that the disclosure will include all embodiments falling within the scope of the appended claims. Various examples have been described. These and other examples are within the scope of the following claims.

Claims

CLAIMS:

1. A chemical processing unit, the chemical processing unit comprising: a ceramic-containing structure; and a coating layer in contact with at least a portion of the ceramic-containing structure and capable of reducing or preventing degradation of the ceramic-containing structure by a process fluid at a processing temperature, wherein the process fluid includes two or more of hydrogen gas, oxygen gas, carbon monoxide gas, carbon dioxide gas, water vapor, and a gaseous hydrocarbon; wherein the coating layer includes one or more coating materials following at least one of the chemical formulas: MXOZ, MxSiyOz, and MxPyOz, wherein M is a metal, x ranges from 1 to 4, y ranges from 1 to 4, and z ranges from 1 to 7.

2. The chemical processing unit of claim 1, wherein the metal is Zirconium or Aluminum.

3. The chemical processing unit of claim 1, wherein the metal is a rare-earth metal including at least one of Scandium, Yttrium, Lanthanum, Cerium, Praseodymium, Neodymium, Promethium, Samarium, Europium, Gadolinium, Terbium, Dysprosium, Holmium, Erbium, Thulium, Ytterbium, and Lutetium.

4. The chemical processing unit of any one of claims 1-3, wherein x ranges from 1 to 4, y ranges from 1 to 4, and z is either 3, 4, or 7.

5. The chemical processing unit of claim 1, wherein the one or more coating materials are selected from Y2SiO5, Y2Si2O7, YPO4, Y2O3, YbSiOs, Yb2Si2O7, YbPO4, TbSi2, Sc2SiO5, and ErPO4.

6. The chemical processing unit of any one of claims 1-5, wherein the process fluid includes hydrogen and at least one of carbon monoxide gas, carbon dioxide gas, water vapor, and a gaseous hydrocarbon; and wherein the process fluid is present within at least a portion of the chemical processing unit.

7. The chemical processing unit of any one of claims 1-6, wherein the processing temperature is between 500 °C and 1200 °C.

8. The chemical processing unit of any one of claims 1-7, wherein a difference in a first coefficient of thermal expansion of the ceramic-containing structure and a second coefficient of thermal expansion of the coating layer is less than 7 10'6 / °C.

9. The chemical processing unit of any one of claims 1-8, wherein the coating layer exhibits an average thermal conductivity of greater than 1 W / m*K.

10. The chemical processing unit of any one of claims 1-9, wherein the chemical processing unit is a chemical reactor or a heat exchanger.

11. The chemical processing unit of any one of claims 1-9, wherein the chemical processing unit is a water gas shift reactor, a reverse-water gas shift reactor, a dry methane reforming reactor, a steam methane reforming reactor, or an autothermal reformer.

12. The chemical processing unit of any one of claims 1-11, wherein the ceramiccontaining structure includes at least one of silicon carbide, silicon nitride, quartz, mullite, aluminum oxide, zirconia, a reinforced carbon composite, cordierite, and aluminum nitride.

13. The chemical processing unit of any one of claims 1-12, including at least one inlet for introducing at least one of hydrogen gas, carbon monoxide gas, carbon dioxide gas, water vapor, and a gaseous hydrocarbon into the chemical processing unit.

14. A chemical reactor, the chemical reactor comprising: a ceramic-containing structure; and a coating layer in contact with at least a portion of the ceramic-containing structure, the coating layer including one or more coating materials following at least one of the chemical formulas: MXOZ, MxSiyOz, and MxPyOz, wherein M is a metal, x ranges from 1 to 4, y ranges from 1 to 4, and z ranges from 1 to 7, wherein the chemical reactor is capable of performing a chemical reaction where a process fluid is present in at least a portion of the chemical reactor, the process fluid including two or more of hydrogen gas, oxygen gas, carbon monoxide gas, carbon dioxide gas, water vapor, and a gaseous hydrocarbon.

15. The chemical reactor of claim 14, wherein the metal is Zirconium or Aluminum.

16. The chemical reactor of claim 14, wherein the metal is a rare-earth metal including at least one of Scandium, Yttrium, Lanthanum, Cerium, Praseodymium, Neodymium, Promethium, Samarium, Europium, Gadolinium, Terbium, Dysprosium, Holmium, Erbium, Thulium, Ytterbium, and Lutetium.

17. The chemical reactor of any one of claims 14-16, wherein x ranges from 1 to 4, y ranges from 1 to 4, and z is either 3, 4, or 7.

18. The chemical reactor of claim 14, wherein the one or more coating materials are selected from Y2SiO5, Y2Si2O7, YPO4, Y2O3, YbSiOs, Yb2Si2O7, YbPO4, TbSi2, Sc2SiO5, and ErPO4.

19. The chemical reactor of any one of claims 14-18, wherein the chemical reactor is a water gas shift reactor, a reverse-water gas shift reactor, a dry methane reforming reactor, a steam methane reforming reactor, or an autothermal reformer.

20. The chemical reactor of any one of claims 14-19, wherein the chemical reaction is performed at a process temperature of at least 500 °C.

21. The chemical reactor of any one of claims 14-20, wherein the ceramic-containing structure includes at least one of silicon carbide, silicon nitride, quartz, mullite, aluminum oxide, zirconia, a reinforced carbon composite, cordierite, and aluminum nitride.

22. The chemical reactor of any one of claims 14-21, wherein the ceramic-containing structure includes silicon carbide.

23. A method for performing a chemical reaction, the method comprising: introducing process fluids into a chemical processing unit, the process fluids including two or more of hydrogen gas, oxygen gas, carbon monoxide gas, carbon dioxide gas, water vapor, and a gaseous hydrocarbon, wherein the chemical processing unit includes: a ceramic-containing structure; and a coating layer in contact with at least a portion of the ceramic-containing structure, wherein the coating layer includes one or more coating materials following at least one of thechemical formulas: MXOZ, MxSiyOz, and MxPyOz, wherein M is a metal, x ranges from 1 to 4, y ranges from 1 to 4, and z ranges from 1 to 7.

24. The method of claim 23, wherein the process fluids include hydrogen gas and at least one of carbon monoxide gas, carbon dioxide gas, water vapor, and a gaseous hydrocarbon.

25. The method of claim 23, wherein the chemical reaction is selected from a water gas shift reaction, a reverse-water gas shift reaction, dry methane reforming, steam methane reforming, and autothermal reforming.

26. The method of any one of claims 23-25, wherein the chemical reaction is performed at a process temperature of at least 500 °C.

27. The method of any one of claims 23-26, wherein the chemical reaction is performed at a process temperature ranging from about 500 °C to about 1200 °C.

28. The method of any one of claims 23-27, wherein the metal is Zirconium or Aluminum.

29. The method of any one of claims 23-27, wherein the metal is a rare-earth metal including at least one of Scandium, Yttrium, Lanthanum, Cerium, Praseodymium, Neodymium, Promethium, Samarium, Europium, Gadolinium, Terbium, Dysprosium, Holmium, Erbium, Thulium, Ytterbium, and Lutetium.

30. The method of any one of claims 23-29, wherein x ranges from 1 to 4, y ranges from 1 to 4, and z is either 3, 4, or 7.

31. The method of claim 23, wherein the one or more coating materials are selected from Y2SiO5, Y2Si2O7, YPO4, Y2O3, YbSiOs, Yb2Si2O7, YbPO4, TbSi2, Sc2SiO5, and ErPO4.

32. A method of applying a coating to a ceramic-containing structure to form a barrier layer, the method comprising:(a) forming a coating mixture by mixing one or more carriers with one or more coating materials following at least one of the chemical formulas: MXOZ, MxSiyOz, and MxPyOz, wherein M is a metal, x ranges from 1 to 4, y ranges from 1 to 4, and z ranges from 1 to 7;(b) contacting the coating mixture with at least a portion of a ceramic-containing structure;(c) treating the coating mixture to form a coating layer;(d) optionally repeating step (b); and(e) optionally repeating step (c).

33. The method of claim 32, wherein the one or more carriers includes at least one of an organic polymer, an organic polymer precursor, and an organic coordination polymer.

34. The method of claim 33, wherein the organic polymer includes a polycarbosilane.

35. The method of any one of claims 32-34, wherein the metal is Zirconium or Aluminum.

36. The method of any one of claims 32-34, wherein the metal is a rare-earth metal including at least one of Scandium, Yttrium, Lanthanum, Cerium, Praseodymium, Neodymium, Promethium, Samarium, Europium, Gadolinium, Terbium, Dysprosium, Holmium, Erbium, Thulium, Ytterbium, and Lutetium.

37. The method of any one of claims 32-36, wherein x ranges from 1 to 4, y ranges from 1 to 4, and z is either 3, 4, or 7.

38. The method of any one of claims 32-37, wherein a volume percentage of the one or more coating materials in the coating mixture ranges from about 5 vol% to about 40 vol%.

39. The method of any one of claims 32-38, wherein treating the coating mixture includes pyrolysis or irradiation curing.

40. The method of any one of claims 32-39, wherein contacting the coating mixture with at least a portion of the ceramic-containing structure forms a layer with a thickness ranging from about 5 microns to about 200 microns.

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