Patent Description:
Synthesis gas, also referred to as syngas, is a fuel gas mixture that includes hydrogen, carbon monoxide, and sometimes carbon dioxide. Syngas is combustible and can be used as a fuel of internal combustion engines. In some cases, syngas can be used as an intermediate for producing synthetic petroleum for use as a fuel or lubricant. Syngas can also be used to produce methanol or as a hydrogen source for various processes. Hydrocarbon reforming is one example of a process for producing syngas.

<CIT> describes a method for the thermo-neutral reforming of liquid hydrocarbon fuels which employs a Ni, Ce<NUM>O<NUM>, La<NUM>O<NUM>, PtZrO<NUM>, Rh and Re catalyst having dual functionalities to achieve both combustion and steam reforming.

<CIT> describes catalysts capable of catalyzing the dry reforming of methane. The catalysts have a core-shell structure with the shell surrounding the core. The shell has a redox-metal oxide phase that includes a metal dopant incorporated into the lattice framework of the redox-metal oxide phase. An active metal is deposited on the surface of the shell.

This disclosure describes technologies relating to hydrocarbon reforming.

The invention relates to a dry reforming process as from claim <NUM>.

This, and other aspects, can include one or more of the following features.

In some implementations, the feed stream is preheated to a temperature in a range of from about <NUM> degrees Celsius (°C) to about <NUM>.

In some implementations, an operating pressure within the reactor during the dry reforming reaction is in a range of from about <NUM> bar to about <NUM> bar.

In some implementations, the feed stream has a carbon dioxide to hydrocarbon ratio in a range of from about <NUM>:<NUM> to about <NUM>:<NUM>.

In some implementations, the carbon dioxide to hydrocarbon ratio of the feed stream is in a range of from about <NUM>:<NUM> to about <NUM>:<NUM>.

In some implementations, the feed stream includes water.

In some implementations, the feed stream has a water to carbon ratio in a range of from about <NUM>:<NUM> to about <NUM>:<NUM>.

In some implementations, the water to carbon ratio of the feed stream is in a range of from about <NUM>:<NUM> to about <NUM>:<NUM>.

The catalyst includes zirconium oxide (ZrO<NUM>), rhodium (Rh), rhenium (Re), and an aluminate support.

In some implementations, the catalyst includes about <NUM> weight percent (wt. %) to about <NUM> wt. % of Ni, about <NUM> wt. % to about <NUM> wt. % of Ce<NUM>O<NUM>, about <NUM> wt. % to about <NUM> wt. % of La<NUM>O<NUM>, about <NUM> wt. % to about <NUM> wt. % of Pt, up to about <NUM> wt. % of ZrO<NUM>, up to about <NUM> wt. % of Rh, and up to about <NUM> wt.

In some implementations, potassium (K) is incorporated into the aluminate support.

In some implementations, the catalyst includes about <NUM> wt. % to about <NUM> wt.

The details of one or more implementations of the subject matter of this disclosure are set forth in the accompanying drawings and the description.

This disclosure describes reforming of hydrocarbons. The conversion of hydrocarbon fuels to hydrogen can be carried out by several processes, including hydrocarbon steam reforming, partial oxidation reforming, auto thermal reforming, and dry reforming. Hydrocarbon dry reforming involves the reaction of carbon dioxide (CO<NUM>) with the fuel (for example, methane, CH<NUM>) in the presence of a catalyst and the absence of oxygen to produce hydrogen (H<NUM>) and carbon monoxide (CO) as given in Equation (<NUM>). A mixture of hydrogen and carbon monoxide can be referred to as synthesis gas (syngas). In some cases, syngas also includes carbon dioxide.

The subject matter described in this disclosure can be implemented in particular implementations, so as to realize one or more of the following advantages. Dry reforming produces hydrogen and carbon monoxide in a <NUM>:<NUM> molar ratio, which is suitable for a diverse array of hydroformylation applications. About half of the carbon atoms in the resulting syngas from the dry reforming process originates from the carbon dioxide instead of the methane. This reduces the dependency of the dry reforming process on methane feedstock in comparison to other reforming processes (for example, steam reforming in which all of the carbon atoms originate from the methane). Further, carbon dioxide, which is a known greenhouse gas, is feedstock for the dry reforming process to form a useful product instead of, for example, being expelled into the atmosphere. The catalyst described herein exhibits resistance to coke formation and sintering, even under elevated temperature and pressure conditions. The processes and catalysts described can allow for economical ways to reduce greenhouse gas emissions. The processes described can integrate renewable hydrogen in existing industrial processes and can mitigate carbon footprint chemicals and fuels.

Although dry reforming has been known, currently known catalysts, for example, nickel-alumina based catalysts, can suffer from deactivation due to excessive coke deposition and agglomeration (that is, sintering) of metal particles at the elevated temperatures required for dry reforming, which can cause reduction of usable surface area of the catalyst. Sintering involves agglomeration of small metal particles to form larger metal particles and results in the reduction of active sites of the catalyst. Coking involves a carbon-containing compound cracking on the surface of the catalyst, which gives selectivity to undesirable side reaction products and also results in the reduction of active sites of the catalyst. Catalysts based on Group VIII noble metals may be less sensitive to coking in comparison to nickel based catalysts, but they can also be more expensive to form and can also be more prone to sintering. Certain precious metals, such as platinum (Pt), palladium (Pd), iridium (Ir), rhodium (Rh), and ruthenium (Ru) can exhibit favorable dry reforming activity while resisting deactivation via coking and sintering.

Referring to <FIG>, a system <NUM> includes a feed stream <NUM>, a preheater <NUM>, and a reactor <NUM>. The feed stream <NUM> includes a hydrocarbon fuel and carbon dioxide. The hydrocarbon fuel includes a hydrocarbon, such as methane, propane, butane, other hydrocarbons with up to twelve carbon atoms, or a mixture of these. In some implementations, the hydrocarbon fuel includes liquid hydrocarbon that have been vaporized. In some implementations, the feed stream <NUM> has a carbon dioxide to hydrocarbon ratio in a range of from about <NUM>:<NUM> to about <NUM>:<NUM>. In some implementations, the feed stream <NUM> has a carbon dioxide to hydrocarbon ratio in a range of from about <NUM>:<NUM> to about <NUM>:<NUM>. For example, the feed stream <NUM> has a carbon dioxide to methane ratio in a range of from about <NUM>:<NUM> to about <NUM>:<NUM> or from about <NUM>:<NUM> to about <NUM>:<NUM>. The feed stream <NUM> is free of oxygen gas (O<NUM>).

The feed stream <NUM> flows to the preheater <NUM>. The preheater <NUM> is configured to preheat the feed stream <NUM>. In some implementations, the preheater <NUM> is configured to preheat the feed stream <NUM> to a temperature in a range of from about <NUM> degrees Celsius (°C) to about <NUM>. In some implementations, the preheater <NUM> is configured to preheat the feed stream <NUM> to a temperature in a range of from about <NUM> to about <NUM>. In some implementations, the preheater <NUM> is configured to preheat the feed stream <NUM> to a temperature in a range of from about <NUM> to about <NUM>. Referring to Equation (<NUM>), the dry reforming reaction is endothermic. In some implementations, preheating the feed stream <NUM> to a temperature that is greater than <NUM> can improve selectivity towards the generation of hydrogen and carbon monoxide (which are the preferred products) and away from forming other carbon-containing compounds. Preheating the feed stream <NUM> (for example, to a temperature greater than <NUM> or greater than <NUM>) can mitigate methane cracking both during the preheating process and in the dry operating mode (that is, without addition of steam) of the dry reforming process.

The preheated feed stream <NUM> exits the preheater <NUM> and flows to the reactor <NUM>. In some implementations, the reactor <NUM> is a packed bed reactor. In some implementations, the reactor <NUM> is a fluidized bed reactor. Within the reactor, the methane reacts with the carbon dioxide to produce syngas <NUM> (carbon monoxide and hydrogen). In other words, the dry reforming reaction represented by Equation (<NUM>) occurs within the reactor <NUM>.

The reactor <NUM> includes a catalyst. Flowing the preheated feed stream <NUM> to the reactor <NUM> brings the preheated feed stream <NUM> in contact with the catalyst. In the absence of oxygen, the catalyst speeds up and causes the dry reforming reaction within the reactor for a period of time sufficient to reform the hydrocarbon fuel (for example, methane) to produce the syngas <NUM>. Because oxygen gas is not introduced to the reactor <NUM>, combustion does not take place within the reactor <NUM>. In some implementations, an operating pressure within the reactor <NUM> during the dry reforming reaction is in a range of from about <NUM> bar to about <NUM> bar. On one hand, as the dry reforming reaction forms a volume of products that is larger than the volume of reactants, so in some cases lower operating pressure within the reactor <NUM> may be preferred during the dry reforming reaction. On the other hand, a higher operating pressure allows for increased throughput of reactants being processed within the reactor <NUM>, so in some cases higher operating pressure within the reactor <NUM> may be preferred during the dry reforming reaction. In some implementations, the operating pressure within the reactor <NUM> depends on the operating pressures of downstream operations (for example, syngas application or purification). For example, in applications using syngas to produce dimethyl ether (DME), the operating pressure of such applications tend to be higher, so the syngas produced from the reactor <NUM> can be compressed, and the operating pressure within the reactor <NUM> can be optimized for improved conversion at pressures greater than <NUM> bar. In some implementations, coking becomes more dominant at higher pressures, especially in cases where the dry reforming reaction is completely dry (that is, there is no addition of water in the form of steam), so in such conditions, an operating pressure within the reactor <NUM> during the dry reforming reaction is in a range of from about <NUM> bar to about <NUM> bar. The range of operating pressure can be expanded through the addition of water in the form of steam with the feed to the reactor <NUM>. The operating pressure within the reactor <NUM> during the dry reforming reaction can be determined based on one or more of the aforementioned factors and economics of the process.

In some implementations, the catalyst within the reactor <NUM> is pre-treated. For example, the catalyst is preheated within the reactor <NUM>, such that the catalyst is at a desired temperature before the feed stream <NUM> is flowed to the reactor <NUM>. In some implementations, the inner volume of the reactor <NUM> is preheated, such that the operating temperature within the reactor <NUM> is at a desired temperature before the feed stream <NUM> is flowed to the reactor <NUM>. In some implementations, the desired temperature of the catalyst, operating temperature within the reactor <NUM>, or both are the same as or within a deviation of <NUM>% from the temperature to which the feed stream <NUM> is preheated in the preheater <NUM>.

The catalyst includes a rare earth group metal oxide, lanthanum oxide (La<NUM>O<NUM>), cerium oxide (Ce<NUM>O<NUM>), a mixture of both. The catalyst includes zirconium oxide (ZrO<NUM>). The catalyst includes nickel (Ni), a reducible compound of Ni (for example, nickel oxide (NiO)), or a mixture of both. The catalyst includes platinum (Pt), Rh, a mixture of both. The platinum group metal can be included in pure elemental form or as a part of a chemical compound that includes the platinum group metal. The catalyst includes rhenium (Re). The Group VIIB metal can function as a promoter to enhance the efficiency of the dry reforming activity of the catalyst.

In some implementations, the catalyst includes about <NUM> weight percent (wt. %) to about <NUM> wt. In some implementations, the catalyst includes about <NUM> wt. % to about <NUM> wt. % of Ce<NUM>O<NUM>. In some implementations, the catalyst includes about <NUM> wt. % to about <NUM> wt. % of La<NUM>O<NUM>. In some implementations, the catalyst includes about <NUM> wt. % to about <NUM> wt. In some implementations, the catalyst includes up to about <NUM> wt. % ZrO<NUM>. In some implementations, the catalyst includes up to about <NUM> wt. In some implementations, the catalyst includes up to about <NUM> wt.

The catalyst is supported on an aluminate support. In such implementations, the aluminate support can be considered a portion of the catalyst. The aluminate support can include magnesium aluminate, calcium aluminate, or a mixture of both. In some implementations, an alkaline metal, such as potassium (K), is incorporated into the aluminate support. Including alkaline metal in the aluminate support can mitigate coke formation on the catalyst and can therefore mitigate catalyst deactivation. In implementations where the catalyst is supported on an aluminate support incorporated with K, the catalyst can include about <NUM> wt. % to about <NUM> wt.

In some implementations, catalyst includes a refractory support that includes alumina (for example, theta-alumina), magnesium aluminate, or a mixture of both. In some implementations, a refractory cement that is based on calcium aluminate is incorporated into the catalyst to improve the mechanical strength of the catalyst. In some implementations, the catalyst has a specific surface area in a range of from about <NUM> square meters per gram (m<NUM>/g) to about <NUM><NUM>/g.

The refractory support can be provided in different shapes, such as spheres, extrudates, or rings. For production of hydrogen-rich gas for use in fuel cells, it can be beneficial to use refractory supports in the form of spheres, for example, having diameters within a range of from about <NUM> millimeter to about <NUM> millimeters; complex extrudates, for example, trilobe, quadralobe, or raschig rings; or honeycomb structure. For large-scale production of hydrogen-rich gas (for example, greater than <NUM>,<NUM> normal cubic meters per day), it can be beneficial to use refractory supports in the form of rings with multiple holes.

In some implementations, the catalyst is prepared by a multiple step sequence of impregnation, calcination, and reduction of the components on the support. The catalyst impregnation can be carried out using an aqueous solution of a soluble salt, such as a nitrate salt. In some implementations, the rhodium and rhenium metal salts are impregnated after which they decompose upon subsequent heat treatment to form corresponding oxides. After impregnation, the composite material is dried (calcined) at a slow heating rate, for example, of about <NUM> increase per minute until reaching about <NUM>, and then the temperature is maintained at about <NUM> for about one hour. The temperature is then increased to about <NUM> at a slow heating rate, for example, of about <NUM> increase per minute, and then the temperature is maintained at about <NUM> for about <NUM> hours. The aforementioned heating (calcination) steps can be carried out in the presence of air or another oxygen containing gas. In some implementations, after impregnation and before heating, the catalyst can be treated at about <NUM> for about <NUM> to about <NUM> minutes with an ammonia containing gas. The catalyst can then be reduced with a hydrogen containing gas at a temperature in a range of from about <NUM> to about <NUM> for about <NUM> hours. The aforementioned impregnation, calcination, and reduction steps can be repeated with salts of Pt and Zr. The aforementioned impregnation, calcination, and reduction steps can be repeated with salts of Ni, Ce, and La. The reduction step for the salts of Ni, Ce, and La can be conducted at a temperature in a range of from about <NUM> to about <NUM>,<NUM>, from about <NUM> to about <NUM>, or from about <NUM> to about <NUM>.

In some implementations, the catalyst is prepared by a single step sequence of impregnation, calcination, and reduction at a temperature in a range of from about <NUM> to about <NUM>,<NUM>, from about <NUM> to about <NUM>, or to about <NUM> to about <NUM>. The refractory support can be impregnated with an aqueous solution of a soluble salt, such as a nitrate salt of Ni, Ce, La, and Pt. After impregnation, the composite material is dried (calcined) at a slow heating rate, for example, of about <NUM> increase per minute until reaching about <NUM>, and then the temperature is maintained at about <NUM> for about one hour. The temperature is then increased to about <NUM> at a slow heating rate, for example, of about <NUM> increase per minute, and then the temperature is maintained at about <NUM> for about <NUM> hours. The temperature is then increased to about <NUM> to about <NUM>. The aforementioned heating (calcination) steps can be carried out in the presence of air or another oxygen containing gas. The catalyst can then be reduced with a hydrogen containing gas at a temperature in a range of from about <NUM> to about <NUM>,<NUM>, from about <NUM> to about <NUM>, or from about <NUM> to about <NUM>. In some implementations, depending on the volume of pores in the support, the impregnation, drying, and calcination can be repeated one or more times to obtain desired contents of each component in the catalyst.

In some implementations, the feed stream <NUM> also includes water (H<NUM>O) in the form of steam. In some implementations, the feed stream <NUM> has a water to carbon (that is, carbon atoms from any carbon-containing species, such as the carbon dioxide and the hydrocarbon fuel) ratio in a range of from about <NUM>:<NUM> to about <NUM>:<NUM>. In some implementations, the feed stream <NUM> has a water to carbon ratio in a range of from about <NUM>:<NUM> to about <NUM>:<NUM>. Including steam in the feed stream <NUM> can reduce the severity of the carbon-carbon reaction at the operating conditions of the dry reforming reaction within the reactor <NUM>. Including steam in the feed stream <NUM> can mitigate coke formation on the catalyst and can therefore mitigate catalyst deactivation. Including steam in the feed stream <NUM> can increase the hydrogen to carbon monoxide ratio in the syngas <NUM> that is produced by the reactor <NUM>. Including steam in the feed stream <NUM> can improve selectivity of the catalyst in producing syngas <NUM> as opposed to other carbon-containing compounds.

<FIG> illustrates an implementation of the system <NUM> that is substantially similar to the system <NUM> shown in <FIG>. In some implementations, as shown in <FIG>, the system <NUM> includes an additional hydrogen stream <NUM> that can be mixed with the syngas <NUM> exiting the reactor <NUM>. The additional hydrogen stream <NUM> can be sourced, for example, from electrolysis of water using renewable energy, allowing for the chemicals/fuels produced from the syngas <NUM> to have a decreased carbon footprint. The addition of hydrogen to the syngas <NUM> can increase the hydrogen to carbon monoxide ratio for tailoring to downstream processes. For example, some processes that may favor an increased hydrogen to carbon monoxide ratio in the syngas <NUM> include methanol production, ethanol production, and acetic acid production.

<FIG> is a flow chart of an example dry reforming process <NUM> for producing a syngas from a hydrocarbon fuel. The system <NUM> can implement the dry reforming process <NUM>. At step <NUM>, a feed stream including hydrocarbon fuel and carbon dioxide (such as the feed stream <NUM>) is preheated. For example, the preheater <NUM> preheats the feed stream <NUM> at step <NUM>. In some implementations, the feed stream <NUM> is preheated to a temperature in a range of from about <NUM> to about <NUM> at step <NUM>. As mentioned previously, the feed stream <NUM> can also include water in the form of steam. In some implementations, the dry reforming process <NUM> includes mixing the hydrocarbon fuel (for example, methane) with the carbon dioxide to form the feed stream <NUM> before step <NUM>. In some implementations, the dry reforming process <NUM> includes mixing the hydrocarbon fuel (for example, methane) with the carbon dioxide and water to form the feed stream <NUM> before step <NUM>.

At step <NUM>, the preheated feed stream (such as the preheated feed stream <NUM>) is flowed to a reactor including a catalyst (such as the reactor <NUM>). The catalyst can be the catalyst that was described previously. Flowing the preheated feed stream <NUM> to the reactor <NUM> at step <NUM> brings the preheated feed stream <NUM> into contact with the catalyst. In the absence of oxygen, the catalyst causes a dry reforming reaction (for example, the reaction represented by Equation (<NUM>)) within the reactor <NUM> for a period of time sufficient to reform the hydrocarbon fuel to produce the syngas (such as the syngas <NUM>). In some implementations, the feed stream is brought into contact with the catalyst in the absence of oxygen at a gas hourly space velocity in a range of from about <NUM>,<NUM>-<NUM> to about <NUM>,<NUM>-<NUM> at step <NUM>. In some implementations, an operating pressure within the reactor during the dry reforming reaction at step <NUM> is in a range of from about <NUM> bar to about <NUM> bar.

The syngas <NUM> can be discharged from the reactor <NUM>. In some implementations, additional hydrogen can be mixed with the syngas <NUM> discharged from the reactor <NUM> to increase the hydrogen to carbon monoxide ratio. For example, the hydrogen stream <NUM> can be mixed with the syngas <NUM>.

<FIG>, and <FIG>, provide various plots that illustrate the thermodynamic equilibrium product compositions of the dry reforming process over a range of operating temperatures at various operating pressures. <FIG>, and <FIG>, demonstrate that selectivity of syngas (hydrogen and carbon monoxide) generally increases with increasing operating temperature. <FIG> is a plot that illustrates the effect of operating pressure on carbon yields (coking) of the dry reforming process. <FIG> demonstrates that coke formation generally increases with increasing operating pressure and generally decreases with increasing operating temperature. In all examples shown in <FIG>, <FIG>, the CH<NUM>:CO<NUM> in the feed stream was <NUM>:<NUM>.

<FIG> provide various plots that illustrate the effect of operating pressure (<NUM> bar, <NUM> bar, and <NUM> bar, respectively) on hydrocarbon conversion rate, product yield, and feed/product compositions of the dry reforming process at an operating temperature of <NUM>. The horizontal dotted lines in <FIG> represent expected conversions, product yields, and product compositions, respectively. The connected data points in <FIG> demonstrate the catalyst performances with a feed stream including a CH<NUM>:CO<NUM> ratio of <NUM>:<NUM> at <NUM> and the various operating pressures.

For each of the experimental runs whose results are shown in the plots of <FIG>, <FIG>, <FIG>: the gas hourly space velocity was <NUM>,<NUM>-<NUM>; the molar compositional ratio of CH<NUM>:CO<NUM>:N<NUM>:He in the feed stream was <NUM>:<NUM>:<NUM>:<NUM>; the catalyst was pre-treated to <NUM> for three hours; and total reaction runtime was <NUM> hours. These experimental runs demonstrate effective performance of the catalyst at high temperatures (for example, <NUM> or greater) at an operating pressure in a range of from about <NUM> bar to about <NUM> bar.

<FIG> provide various plots that illustrate the effect of gas hourly space velocity (<NUM>,<NUM>-<NUM> and <NUM>,<NUM>-<NUM>) on hydrocarbon conversion rate, product yield, and feed/product compositions, respectively, of the dry reforming process at an operating temperature of <NUM> and an operating pressure of <NUM> bar. For each of the experimental runs whose results are shown in the plots of <FIG>: the molar compositional ratio of CH<NUM>:CO<NUM>:N<NUM>:He in the feed stream was <NUM>:<NUM>:<NUM>:<NUM>; the catalyst was pre-treated to <NUM> for six hours; and total reaction runtime was <NUM> hours. Greater gas hourly space velocities tend to have less single pass conversion and typically means that more recycle occurs in the process. <FIG> demonstrate that the catalyst exhibits stable performance in reaching equilibrium compositions over a range of gas hourly space velocities at the operating temperature of <NUM> and the operating pressure of <NUM> bar.

<FIG> provide various plots that illustrate the effect of operating temperature (<NUM> and <NUM>) on hydrocarbon conversion rate, product yield, and feed/product compositions, respectively, of the dry reforming process at an operating pressure of <NUM> bar when the feed stream includes water (CH<NUM>:CO<NUM>:H<NUM>O ≈ <NUM>:<NUM>:<NUM>). For each of the experimental runs whose results are shown in the plots of <FIG>: the molar compositional ratio of CH<NUM>:CO<NUM>:H<NUM>O:N<NUM>:He in the feed stream was <NUM>:<NUM>:<NUM>:<NUM>:<NUM>; the catalyst was pre-treated to <NUM> for six hours; and total reaction runtime was <NUM> hours. <FIG> demonstrate the impact of adding steam in the feed stream. Adding steam can increase the H<NUM>:CO ratio in the product at milder operating conditions (for example, at cooler temperatures), which can improve catalyst operating life. Further, increased H<NUM>:CO ratios in the product can be favorable for various downstream processes (mentioned previously).

<FIG> provide various plots that illustrate the effect of operating temperature (<NUM> and <NUM>) on hydrocarbon conversion rate, product yield, and feed/product compositions, respectively, of the dry reforming process at an operating pressure of <NUM> bar when the feed stream has a decreased CH<NUM>:CO<NUM> ratio (<NUM>:<NUM>). For each of the experimental runs whose results are shown in the plots of <FIG>: the molar compositional ratio of CH<NUM>:CO<NUM>:N<NUM>:He in the feed stream was <NUM>:<NUM>:<NUM>:<NUM>; the catalyst was pre-treated to <NUM> for six hours; and total reaction runtime was <NUM> hours. <FIG> demonstrate the impact of adjusting the CH<NUM>:CO<NUM> ratio in the feed stream at dry operating conditions (no addition of steam) at the various operating temperatures. The stability of these results may demonstrate favorable conditions in mitigating coking. With increased CO<NUM> content in the feed stream, coke deposits that form during the reaction can potentially be further reacted with CO<NUM> to form additional CO (for example, via the reverse Boudouard reaction). Decreasing the CH<NUM>:CO<NUM> ratio in the feed stream may result in decreased H<NUM>:CO ratios in the product syngas, but the H<NUM>:CO ratio in the syngas can be adjusted (see, for example, <FIG>).

Although some of the aforementioned examples included inert gas (for example, nitrogen (N<NUM>), helium (He), or both) in the feed stream, the inert gas was included in order to verify quality of the experiments through mass balance checks, and the inert gas is not necessarily included in industrial applications of the dry reforming processes described here.

While this specification contains many specific implementation details, these should not be construed as limitations on the scope of what may be claimed, but rather as descriptions of features that may be specific to particular implementations. Certain features that are described in this specification in the context of separate implementations can also be implemented, in combination, in a single implementation. Conversely, various features that are described in the context of a single implementation can also be implemented in multiple implementations, separately, or in any suitable sub-combination. Moreover, although previously described features may be described as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can, in some cases, be excised from the combination, and the claimed combination may be directed to a sub-combination or variation of a sub-combination.

As used in this disclosure, the terms "a," "an," or "the" are used to include one or more than one unless the context clearly dictates otherwise. The term "or" is used to refer to a nonexclusive "or" unless otherwise indicated. The statement "at least one of A and B" has the same meaning as "A, B, or A and B. " In addition, it is to be understood that the phraseology or terminology employed in this disclosure, and not otherwise defined, is for the purpose of description only and not of limitation. Any use of section headings is intended to aid reading of the document and is not to be interpreted as limiting; information that is relevant to a section heading may occur within or outside of that particular section.

As used in this disclosure, the term "about" or "approximately" can allow for a degree of variability in a value or range, for example, within <NUM>%, within <NUM>%, or within <NUM>% of a stated value or of a stated limit of a range.

As used in this disclosure, the term "substantially" refers to a majority of, or mostly, as in at least about <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, or at least about <NUM>% or more.

Values expressed in a range format should be interpreted in a flexible manner to include not only the numerical values explicitly recited as the limits of the range, but also to include all the individual numerical values or sub-ranges encompassed within that range as if each numerical value and sub-range is explicitly recited. For example, a range of "<NUM>% to about <NUM>%" should be interpreted to include about <NUM>% to about <NUM>%, as well as the individual values (for example, <NUM>%, <NUM>%, <NUM>%, and <NUM>%) and the sub-ranges (for example, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%) within the indicated range. The statement "X to Y" has the same meaning as "about X to about Y," unless indicated otherwise. Likewise, the statement "X, Y, or Z" has the same meaning as "about X, about Y, or about Z," unless indicated otherwise.

Claim 1:
A dry reforming process (<NUM>) for producing a synthesis gas from a hydrocarbon fuel, comprising:
preheating (<NUM>) a feed stream comprising the hydrocarbon fuel and carbon dioxide; and
flowing (<NUM>) the preheated feed stream to a reactor comprising a catalyst, thereby bringing the preheated feed stream into contact with the catalyst in the absence of oxygen and causing a dry reforming reaction within the reactor for a period of time sufficient to reform the hydrocarbon fuel to produce the synthesis gas, the catalyst comprising nickel (Ni), lanthanum oxide (La<NUM>O<NUM>), cerium oxide (Ce<NUM>O<NUM>), platinum (Pt), zirconium oxide (ZrO<NUM>), rhodium (Rh), rhenium (Re), and an aluminate support.