WO2015193817A1

WO2015193817A1 - Methods for determining the amount of steam required for regeneration of catalysts

Info

Publication number: WO2015193817A1
Application number: PCT/IB2015/054555
Authority: WO
Inventors: YongMan CHOI; Toseef Ahmed; Somak PAUL; Abdullah N. AL-NAFISAH; Ramsey BUNAMA; Khalid M. El-Yahyaoui
Original assignee: Sabic Global Technologies B.V.
Priority date: 2014-06-19
Filing date: 2015-06-16
Publication date: 2015-12-23

Abstract

The invention relates to the regeneration of spent catalysts and provides methods for determining the amount of steam to be used in a regeneration process. The method includes calculating an amount of water adsorbed onto a surface of the catalyst using a thermogravimetric analysis and calculating the amount of steam to be used in the regeneration process of the catalyst based on the amount of water adsorbed to the surface of the catalyst.

Description

METHODS FOR DETERMINING THE AMOUNT OF STEAM REQUIRED

FOR REGENERATION OF CATALYSTS

TECHNICAL FIELD

[0001] The presently disclosed subject matter relates to methods for determining the amount of steam required for regenerating catalysts.

BACKGROUND

[0002] During certain catalytic reactions, coke, e.g., carbonaceous compounds, forms on the surface of catalyst, resulting in the progressive reduction of catalytic activity. Periodic regeneration of the catalyst can be required to reactivate the catalyst and allow the catalyst to be reused in further catalytic reactions. Regeneration is generally performed by the oxidation of the deposited coke on the surface of the catalyst. Gaseous streams, such as oxygen, water vapor or hydrogen, can be used to remove coke deposited on catalysts during the regeneration process. Among them, steam is commonly used as it can be easily obtained and does not require purification before use. Oxidation of the coke on the surface of the catalyst by steam can occur through the following reaction:

C + H₂O ^ CO + H₂ [Formula 1]

[0003] For proper regeneration of spent catalyst, the amount of steam that is to be used in the regeneration process should be of a sufficient amount to efficiently and completely oxide the coke on the surface of the catalyst.

[0004] Catalysts that can be regenerated using steam are known in the art. For example, Japanese Patent Publication No. 2002085971 discloses zirconium oxide-based hydrogenation catalysts that can be regenerated using a process involving water and/or methanol. U.S. Patent No. 2,546,031 discloses a chromium and alumina-based catalyst that can be regenerated using an oxygen containing gas to remove coke from the surface of the catalyst.

[0005] Thermogravimetric analysis (TGA) is a technique that can be used for monitoring the mass of a substance as a function of temperature or time, for example, as a substance is heated or cooled. Methods of using thermogravimetric analysis to determine the properties of substances are known in the art. For example, U.S. Patent Application No. 2013/0225394 discloses a process for monitoring and controlling the bum rate, e.g., the mass of coke that is removed from the catalyst per hour, of a catalyst regeneration cycle by analyzing the composition of partially regenerated catalyst using thermogravimetric analysis. [0006] There remains a need for methods for determining the amount of steam that is required for effective regeneration of a catalyst.

SUMMARY

[0007] Disclosed, in various embodiments, are methods for calculating an amount of steam to be used in a regeneration process of a catalyst.

[0008] A method for calculating an amount of steam to be used in a regeneration process of a catalyst, comprises: determining an amount of water adsorbed onto a surface of the catalyst using a thermogravimetric analysis; and determining the amount of steam to be used in the regeneration process of the catalyst based on the determined amount of adsorbed water.

[0009] A method for calculating an amount of steam to be used in a regeneration process of a catalyst, comprises: determining an amount of water adsorbed onto a surface of the catalyst using a thermogravimetric analysis, wherein the thermogravimetric analysis comprises heating the catalyst to a first temperature, Tj, wherein the first temperature is 650°C; cooling the catalyst from Tj to a second temperature, T₂, wherein the second temperature is 50°C; and measuring a weight change of the catalyst from Tj to T₂, wherein the weight change is the amount of water adsorbed onto the surface of the catalyst; and determining the amount of steam to be used in the regeneration process of the catalyst based on the determined amount of adsorbed water

[0010] These and other features and characteristics are more particularly described below

BRIEF DESCRIPTION OF THE FIGURES

[0011] The following is a brief description of the drawings wherein like elements are numbered alike and which are presented for the purposes of illustrating the exemplary embodiments disclosed herein and not for the purposes of limiting the same.

[0012] FIG. 1 shows an exemplary method in accordance with one embodiment of the presently disclosed subject matter.

[0013] FIG. 2A shows an X-ray diffraction analysis of 01-A12O₃.

[0014] FIG. 2B shows an X-ray diffraction analysis of γ-Αΐ2θ₃.

[0015] FIG. 3 A shows a TGA curve for α-Α1₂0₃.

[0016] FIG. 3B shows a TGA curve for γ-Α1₂0₃.

[0017] FIG. 4A shows an SEM image of α-Α1₂0₃. [0018] FIG. 4B shows an SEM image of γ-Α1₂0₃.

[0019] FIG. 5 shows a TGA curve for γ-Α1₂0₃ powder, where Tj is the initial heating temperature, T₂ is the cooling temperature and T3 is the reheating temperature.

[0020] FIG. 6 shows the H₂0 uptake (W_H2o) as a function ofT₂ variation.

DETAILED DESCRIPTION

[0021] The presently disclosed subject matter provides techniques for determining the amount of steam required for efficient regeneration of a catalyst. In certain embodiments, thermogravimetric analysis is used to accurately estimate the amount of steam that can be used to regenerate a catalyst.

[0022] In certain embodiments, an exemplary method can include determining an amount of water adsorbed onto a surface of the catalyst using a thermogravimetric analysis and determining the amount of steam to be used in the regeneration process of the catalyst. The amount of steam can be determined based on the amount of adsorbed water.

[0023] In certain embodiments, the thermogravimetric analysis can include heating the catalyst to a first temperature, Tj, cooling the catalyst from Tj to a second temperature, T₂, and measuring a weight change of the catalyst from Tj to T₂, where the weight change is the amount of water adsorbed onto the surface of the catalyst.

[0024] In certain embodiments, Tj can be a temperature of about 400°C to about 800°C. In certain embodiments, T₂ can be a temperature of about 50°C to about 500°C.

[0025] In certain embodiments, the catalyst used in the presently disclosed subject matter can include a CATOFIN catalyst, a chromium-based catalyst, a silica-based catalyst, a zirconia-based catalyst, an alumina-based catalyst, a zeolite-based catalyst, or a combinations comprising at least one of the foregoing. For example, but not by way of limitation, the catalyst can be suitable for catalyzing dehydrogenation reactions of alkanes and/or CATOFIN processes. In certain embodiments, the catalyst is a catalyst that can be regenerated using steam.

[0026] In certain embodiments, the thermogravimetric analysis can be performed prior to the catalyst undergoing the regeneration process. Alternatively or additionally, the thermogravimetric analysis can be performed prior to the use of the catalyst in a chemical reaction.

[0027] For the purpose of illustration and not limitation, Figure 1 shows an exemplary method for determining the amount of steam to be used in a regeneration process in accordance with one embodiment of the presently disclosed subject matter. As shown in Figure 1 , the method can include calculating an amount of water adsorbed onto the surface of the catalyst using a thermogravimetric analysis method 101. Thermogravimetric analysis is a technique that can be used to monitor the weight of a substance as a function of temperature. The presently disclosed method can further include calculating the amount of steam to be used in the regeneration process of the catalyst 102 based on the amount of water absorbed from the calculation in 101.

[0028] In certain embodiments, the thermogravimetric analysis of the disclosed method can include heating a sample of catalyst to a first temperature (Tj) from an initial starting temperature (To). The thermogravimetric analysis can also include monitoring changes in the weight (W) or weight percent (W%) of the catalyst during the transition from To to Tj. In certain embodiments, the weight of the water (W_H2o) adsorbed onto the surface of the catalyst can be determined by monitoring and measuring the change in the weight (W) of the catalyst during the transition from T₀ to Tj as represented by Formula 2.

W_H2o = CAT at To - WCAT at Tj [Formula 2]

where WC_AT at Tj is the total weight of the catalyst at Tj and WC_AT at To is the total weight of the catalyst at To.

[0029] In certain embodiments, the weight percent (W%) change of the catalyst can be monitored to determine the weight percent of the catalyst that is water adsorbed onto the surface of the catalyst (W _H2o (%)) during the heating of the catalyst to Tj by the following formula:

W_H20 (%) = WCAT (%) at T₀ - W_CAT (%) at Tj [Formula 3]

where WC_AT (%) at Tj is the total weight of the catalyst at Tj and WC_AT (%) at To is the total weight % of the catalyst being tested at To.

[0030] In certain embodiments, the temperature of Ti can be from about 300°C to about 800°C. For example, Tj can be a temperature greater than about 300°C, greater than about 400°C, greater than about 450°C, greater than about 500°C, greater than about 600°C, greater than about 650°C, greater than about 675°C, greater than about 700°C, greater than about 725°C, greater than about 750°C, greater than about 775°C, greater than about 800°C or greater than about 900°C. To can be any temperature lower than the temperature of Tj, e.g., room temperature.

[0031] The term "about" or "approximately" means within an acceptable error range for the particular value as determined by one of ordinary skill in the art, which will depend in part on how the value is measured or determined, i.e., the limitations of the measurement system. For example, "about" can mean a range of up to 20%, up to 10%, up to 5%, and or up to 1% of a given value.

[0032] In certain embodiments, the heating of the catalyst to Ti can result in at least partial desorption of water from the surface on the catalyst. For example, but not by way of limitation, at least about 50%, at least about 60%, at least about 70%, at least about 80%, at least about 85%, at least about 90%, at least about 91%, at least about 92%, at least about 93%, at least about 94%, at least about 95%, at least about 96%, at least about 97%, at least about 98% or at least about 99% of the water present on the surface of the catalyst is desorbed from the catalyst upon reaching temperature Ti.

[0033] In certain embodiments, the catalyst can be heated to Tj at a controlled heating rate of about 5°C per minute (min), about 10°C per min, about 15°C per min, about 20°C per min, about 25°C per min or about 30°C per min. For example, the catalyst can be heated to Tj at a controlled heating rate of about 10°C per min. The catalyst can be heated for a sufficient amount of time to reach temperature Tj using a particular heating rate. In certain

embodiments, the catalyst can be heated for about 10 minutes to about 100 minutes. For example, the catalyst can be heated for about 20 minutes to about 80 minutes, for about 30 minutes to about 80 minutes, for about 40 minutes to about 80 minutes, for about 50 minutes to about 80 minutes, for about 60 minutes to about 80 minutes, or for about 70 minutes to about 80 minutes.

[0034] The thermogravimetric analysis can further include cooling the heated catalyst to a second temperature, T₂, from Tj. T2 can be of a temperature lower than the temperature of Tj. In certain embodiments, the temperature of T2 can be about 25°C to about 800°C or about 50°C to about 800°C. For example, T₂ can be about 25°C to about 50°C, about 50°C to about 100°C, about 50°C to about 200°C, about 50°C to about 300°C, about 50°C to about 400°C, about 50°C to about 450°C, about 50°C to about 500°C, about 50°C to about 600°C, about 50°C to about 700°C, or about 50°C to about 750°C. In certain embodiments, T₂ is the temperature of the regeneration cycle. For example, and not by way of limitation, the temperature of T2 can be about 650°C. In certain embodiments, T2 can be about 50°C. In certain embodiments, T2 is not a temperature lower than room temperature.

[0035] In certain embodiments, the catalyst can be cooled to T2 at a controlled cooling rate of about 5°C per min, about 1 0°C per min, about 15°C per min, about 20°C per min, about 25°C per min or about 30°C per min. For example, the catalyst can be cooled to T2 at a controlled cooling rate of about 10°C per min. The catalyst can be cooled for a sufficient amount of time to reach temperature Ti using a particular heating rate. In certain embodiments, the catalyst can be cooled from about 10 minutes to about 100 minutes. For example, the catalyst can be cooled from about 20 minutes to about 80 minutes, from about 30 minutes to about 80 minutes, from about 40 minutes to about 80 minutes, from about 50 minutes to about 80 minutes, from about 60 minutes to about 80 minutes or from about 70 minutes to about 80 minutes.

[0036] During the cooling of the catalyst to T₂, water is adsorbed onto the surface of the catalyst. The weight of the water (W_H2o) adsorbed onto the surface of the catalyst can be determined by monitoring and measuring the change in the weight (W) of the catalyst during the transition from Ti to T2 as represented by Formula 4.

W_H2o = CAT at T2 - WCAT at Tj [Formula 4]

where WC_AT at Tj is the total weight of the catalyst at Tj and WC_AT at T2 is the total weight of the catalyst at T₂. In certain embodiments, the weight percent (W%) change of the catalyst can be monitored to determine the weight percent of the catalyst that is water adsorbed onto the surface of the catalyst (W_H2o (%)) during the cooling of the catalyst to T2 by the following formula:

W_H2o (%) = WCAT (%) at T₂ - W_CAT (%) at Tj [Formula 5]

where WC_AT (%) at Tj is the total weight % of the catalyst at Tj and WC_AT (%) at T2 is the total weight % of the catalyst being tested at T₂.

[0037] In certain embodiments, the weight of the water that is adsorbed to the surface of the catalyst can be calculated by Formula 6:

W_H2o (%) = 36.26 l/(l+exp((T₂ + 410.722)/150.443)) [Formula 6]

where W_H2o (%) is the percent of the total weight of the catalyst being tested that is adsorbed water. In certain embodiments, formulas for determining the W_H2o (%) or W_H2o for different catalyst compositions can be derived from fitting curves to data from individual

thermogravimetric analyses, e.g., fitting curves to thermogravimetric data plotted as a function of temperature and the change in W_H2o (%) or the change in WC_AT (%)· The total weight of water adsorbed to the surface of the catalyst can then be determined from the W_H2o (%) value by the following formula:

W_H2o = W_H2o ( ) x WCAT at T₀ [Formula 7]

where WH20 (%) is the percent of the total weight of the catalyst being tested that is adsorbed water and WC_AT at To is the total weight of the catalyst at the initial starting temperature, To. To is the temperature of the catalyst prior to the thermogravimetric analysis and/or the initial starting temperature of the analysis before the catalyst is heated to Tl. [0038] The total weight of a catalyst that can be analyzed in the presently disclosed methods depends on the limitations of the thermogravimetric instrument being used to perform the thermogravimetric analysis. In certain embodiments, the total weight of the catalyst can be about 5 milligrams (mg) to about 30 mg. For example, but not by way of limitation, the total weight of the catalyst can be about 5 mg to about 25 mg, about 5 mg to about 20 mg, about 5 mg to about 15 mg, about 5 mg to about 10 mg, about 10 mg to about 25 mg, about 15 mg to about 25 mg, or about 20 mg to about 25 mg.

[0039] The presently disclosed method can further include calculating the amount of steam to be used in the regeneration process of the catalyst 102. The amount of steam can be calculated based on the amount of water adsorbed onto the surface of the catalyst (W mo or W_H2o %), e.g., as determined by Formulas 2, 3, 4, 5, 6 or 7. In certain embodiments, the amount of steam that can be used in the regeneration process can be calculated by the following formula, where the amount of steam is measured in milliliters per square meter (mL/m²):

Amount of steam (in mL/m ) = V_H2o / Surface Areac_AT [Formula 8]

where V_H2o is the volume of the water that is adsorbed onto the surface of the catalyst during the thermogravimetric analysis and Surface Areac_AT is the surface area of the total catalyst sample being tested. V_H2o can be calculated based on W_H2o using Formula 9, where W_H2o is measured in grams (g), and MW_H2o is measured in grams per mole (g/mol).

H₂₀ = W_H?n (g x 22.4 Liters per mol (L/mol) [Formula 9]

MW_H20 (g/mol)

where MW_H2o is the molecular weight of water. In certain embodiments, the amount of steam is provided in the volume per square meter (m ) of the catalyst, thereby allowing the calculation of the amount of steam necessary for the regeneration of a different weight of catalyst, e.g., the total weight of catalyst used in a manufacture-scale reaction and regeneration process.

[0040] The surface area of the catalyst sample can be determined using any method known in the art. For example, specific surface areas can be measured using a gas adsorption method. A non-limiting example of a gas adsorption method is the Brunauer-Emmett-Teller (BET) multilayer nitrogen adsorption method, which includes contacting the catalyst with a nitrogen gas. In certain embodiments, the BET analysis can be performed using

AUTOSORB-6B obtained from Quantachrome Corp.

[0041] The thermogravimetric analysis and the weight changes of the catalyst as a function of temperature can be measured and performed using a thermogravimetric instrument. The thermogravimetric analysis instrument can include one or more sample pans contained within one or more chambers to allow regulation of temperature, pressure and atmosphere composition. For example, but not by way of limitation, the thermogravimetric instrument can be a vertical balance instrument, which can include a vertical hanging sample pan attached to a balance. Non-limiting examples of such instruments are available from TA Instruments and the Netzsch Group. In certain embodiments, the thermogravimetric instrument can be a horizontal balance instrument, which can include two weighing pans, e.g., a sample pan and a reference sample pan, coupled to a balance in a horizontal arrangement. Non-limiting examples of such instruments are available from TA Instruments and Perkin Elmer Corp.

[0042] The heating and/or cooling of the catalyst during the thermogravimetric analysis can occur in atmospheres of varying composition. For example, but not by way of limitation, the exposure of the catalyst to temperature changes can occur in air or in an inert atmosphere, such as helium or argon. In certain embodiments, the temperature changes can occur in a lean oxygen atmosphere, e.g., 1 to 5% (¾ in N2 or He. In certain embodiments, thermogravimetric analysis is performed in air at an atmospheric pressure of 1 atmosphere (101 kiloPascals (kPa)).

[0043] In certain embodiments, the methods of the present disclosure can be performed prior to the catalyst undergoing a regeneration cycle. Alternatively or additionally, in certain embodiments, the method of the present disclosure can be performed prior to the use of the catalyst in a chemical reaction, e.g., unused or newly prepared catalyst. In certain embodiments, the method can be performed after the catalyst undergoes at least one regeneration cycle.

[0044] In certain embodiments, the disclosed subject matter provides for systems programmed to carry out the methods described herein. For example, the system can include apparatus and/or devices, such as a thermogravimetric analysis instrument, coupled to one or data processors, e.g., computer. In certain embodiments, the data processor can be programmed to receive (i.e., as input) the change in the weight of the catalyst as a function of temperature measured during the thermogravimetric analysis.

[0045] The data processor can be further programmed to provide (i.e., as output) the amount of steam that can be used in a steam-based regeneration process of the catalyst based on the changes in the weight of the catalyst while performing the thermogravimetric analysis. Such output (e.g., the amount of steam) can be, for example, in the form of a report on computer readable medium, printed in paper form and/or displayed on a computer screen or other display. As one of ordinary skill in the art will perceive, the programming can be effectuated in ways that are well known in the art. The system is an important component of the disclosed subject matter, allowing the methods described herein to be implemented with precision and time scales not otherwise achievable.

[0046] The catalysts to be used in the method of the disclosed subject matter can be any catalyst known to one of ordinary skill in the art that can undergo a steam-based regeneration process. For example, but not by way of limitation, the catalyst can be a catalyst that is not sensitive to steam and/or does not undergo chemical reactions in the presence of steam. In certain embodiments, the catalyst can be suitable for catalyzing a CATOFIN process. In certain embodiments, the catalyst can be suitable for catalyzing dehydrogenation of alkanes, e.g., the dehydrogenation of isobutane to isobutylene. For example, catalyst compositions for catalyzing dehydrogenation of alkanes can include, but are not limited to, metal oxides, carbides, hydroxides, or combinations comprising at least one of the foregoing. Non-limiting examples of metals can include, but are not limited to, oxides of chromium (Cr), copper (Cu), manganese (Mn), potassium (K), palladium (Pd), cobalt (Co), cerium (Ce), tungsten (W), platinum (Pt), sodium (Na), cesium (Cs), or a combination comprising at least one of the foregoing.

[0047] The catalyst compositions for use in the methods of the presently disclosed subject matter can further include an inert carrier or support material. Suitable supports can be any support materials, which exhibit good stability at the reaction conditions of the disclosed methods, and are known by one of ordinary skill in the art. In certain embodiments, the support material can include, but is not limited to, aluminum oxide (alumina), magnesia, silica, titania, zirconium dioxide (zirconia), mixtures, or a combination comprising at least one of the foregoing. In certain embodiments, the support material is alumina. In certain embodiments, the support material can include zirconium dioxide.

[0048] U.S. Patent Nos. 6,486,220, 8,551,434 and 8,288,446, incorporated herein by reference in their entireties, disclose catalysts that can be used in the disclosed subject matter. Additional non-limiting examples of catalyst compositions include Cr₂(¾, Cr/ZrCh , Cr/Ai₂0₃, Cr/Si(¾, Cu-Mn/Ai₂0₃, Cr/MgO, or a combination comprising at least one of the foregoing. A non-limiting example of a commercially available Cr/A^Ch catalyst is

CATOFIN™ (Sud-Chemie AG, Munich, Germany).

[0049] In certain embodiments, the catalyst compositions of the present disclosure can further include one or more promoters. Non-limiting examples of promoters include lanthanides, alkaline earth metals, rare earth metals, magnesium, rhenium and alkali metals such as lithium, sodium, potassium, rubidium, cesium, as well as a combination comprising at least one of the foregoing. Additionally, the catalyst can contain at least one co-promoter component such as rhenium, sulphur, molybdenum, tungsten, chromium, or a combination comprising at least one of the foregoing.

[0050] The catalyst used in the present disclosure can be of any shape and size that will provide accurate measurements of the amount of water that can be adsorbed to the surface of the catalyst. For example, but not by way of limitation, the catalyst can be in the form of powder, granules, spheres, pellets, beads, cylinders, trilobe, and quadralobe shaped pieces. In certain embodiments, the catalyst can be in the form of a powder.

[0051] The catalyst used in the present disclosure can be prepared by any catalyst synthesis process well known in the art. See, for example, U.S. Pat. Nos. 6,299,995,

6,293,979 and 8,288,446, each of which is incorporated herein by reference in its entirety. Additional examples include, but are not limited to, spray drying, precipitation, impregnation, incipient wetness, ion exchange, fluid bed coating, physical, or chemical vapor deposition.

[0052] The following example is merely illustrative of the presently disclosed subject matter and should not be considered as limiting in any way.

EXAMPLE 1 : ACCURATE MEASUREMENT OF STEAM REQUIRED FOR

REGENERATION OF CATOFIN CATALYST.

[0053] Regeneration of chromium-based CATOFIN catalysts is performed to increase the catalysts' lifetime after use in reaction processes to remove the coke that accumulates on the surface of the catalyst during the catalytic reaction. Steam (vaporized water) is often used to oxidize the coke on the surface of the catalyst. Therefore, to efficiently use steam for the carbon removal process during the regeneration cycle, it is important to understand water adsorption on catalyst surfaces.

[0054] Among chromium-based CATOFIN catalyst materials, alumina (AI2O₃, aluminum oxide) is used as a support. AI2O₃ is also one of the most widely used ceramic materials in various applications because of its chemical and thermal stability and availability in abundance (E. Dorre, H. Hubner, Processing, Properties, and Applications Series:

Materials Research and Engineering, Springer, 1984). Numerous approaches to preparing AI2O₃ are available, and one of methods is the utilization of AIOOH. The reactant of AIOOH can be transformed to γ δ θ -^a-AL^ by different calcination temperatures. Among the polymorphs, a- and γ- AI2O₃ are the most widely used. γ-Αΐ2θ₃ is more widely used as the support material of catalysts due to its high surface areas and reactivity (M. Trueba, S.P. Trasatti, Eur. J. Inorg. Chem., (2005) 3393-3403).

[0055] In this Example, a thermogravimetric analysis (TAG) method was performed to determine the water uptake amount and rate on catalyst surfaces. In addition, the polymorphs y-AhO and (X-AI2O₃ were analyzed to analyze how the differences in the surface area of support materials affect the amount of water uptake of the catalyst.

[0056] (X-AI2O₃ (provided by Engelhard Corp.) was used without further processing. γ-Αΐ2(¾ was prepared from the calcination of highly hydrogenated boehmite (γ-ΑΙΟΟΗ) obtained from Sasol. Boehmite precursors were calcined in air for 3 hours at 750 °C.

[0057] Both the bohemite precursor and AI2O₃ powders were characterized using several techniques. For example, specific surface areas were measured using a Brunauer- Emmett- Teller (BET) multilayer nitrogen adsorption method using a Quantachrome's AUTOSORB-6B, while thermogravimetric analyses (TGA) were performed using Model Q500 from TA Instruments. To examine surface morphologies of powders, scanning electron micrograph (SEM) images were obtained using a FEI Quanta 200 SEM. X-ray powder diffraction patterns obtained on a Panalytical-X'pert MPD diffractometer were used for determining phase information of the materials.

[0058] As summarized in Table 1, the BET surface area of γ-Αΐ2(¾ was smaller than that of boehmite by 19.3%, while (X-A12O₃ was 12.4 square meters per gram (m²/g), indicating that γ-Αΐ2(¾ and 01-AI2O₃ different particle sizes. As shown in Figures 4 A and 4B, SEM images illustrated that γ-Αΐ2θ₃ was much finer than (X-AI2O₃ (-50 micrometers (μπι) versus 25 μπι) and exhibited different surface areas (Table 1). These differences in particle size were supported by the measurements received by SEM (Figures 4A and 4B), where Figure 4A represents (X-AI2O₃ and Figure 4B represents γ-Αΐ2θ₃. Figure 2 A shows x-ray diffraction (XRD) data in the range of 20° - 80° for (X-A12O₃. Figure 2B shows x-ray diffraction (XRD) data in the range of 20° - 80° for y-A^C^.XRD showed that a-AhO is crystalline in structure, while y-AhO is amorphous in structure.

[0059] Figure 3 A shows typical TGA data for 01-AI2O₃. Figure 3B shows typical TGA data for γ-Αΐ2θ₃. As displayed in Figures 3 A and 3B, a weight loss was initially observed at room temperature in both of the samples. It was observed that the weight loss of the TGA curve of γ-Αΐ2θ₃ was approximately 7.6%, while that of 01-AI2O₃ was almost negligible (- 0.4%). Based on these TGA results and that there was no contamination after a sample preparation, the weight loss observed during the temperature change from room temperature to 800°C was due to the evaporation of the water molecules from the surface of the catalyst. As summarized in Table 1, the surface area of γ-Αΐ₂(¾ was much larger than (X-AI2O₃, and the γ-Α1₂0₃ surfaces possessed a stronger H₂0 uptake capability than 01-AI2O₃ because of its high surface energies. In addition, as shown in Figures 3A and 3B, due to its high surface area, γ- AI2O₃ adsorbed water from the air within a short time.

[0060] On the basis of the results of the TGA and BET analyses, γ-Αΐ₂θ₃ powders were analyzed to examine the behavior of the water uptake on γ-Α1₂0₃ surfaces. As shown in Figure 5, TGA measurements were systematically performed using pure γ-Αΐ₂θ₃. Initially, γ- AI2O₃ was heated to a calcination temperature (Tj) at a heating rate of 10 °C/min, and then, it was cooled to T₂, with a cooling rate of 10°C/min. T3 is the reheating temperature (800°C). At Tj, most of the adsorbed water was observed to be evaporated. While powder was cooled down to T₂, the γ-Αΐ₂θ₃ sample adsorbed water molecules from the air allowing the calculation of the weight of the water that can be adsorbed to the surface of the catalyst. To better understand the water uptake amount as a function of temperature, T2 was varied from 500°C to 50°C.

[0061] As displayed in Figure 6, the water uptake amount measured in weight percent (wt %) was well correlated as a function of temperature (T₂), leading to the following formula:

W_H2o (%) = 36.261/(l+exp((T₂ + 410.722)/150.443)) [Formula 6]

where W_H2o is the water uptake amount at T₂. Formula 6 was derived from curve fitting of the data in Figure 6.

[0062] On the basis of this equation, one can predict how much water adsorbs on γ- AI2O₃ after the regeneration process to a catalytic reaction. For example, if the regeneration and reaction temperatures are 650°C and 580°C, 0.018 wt , 0.01 , and 0.028 , respectively, of H2O can be adsorbed on the surface of the γ-Αΐ₂θ₃ support. It reached equilibrium within 7 minutes according to a cooling rate of 10°C/min. An extrapolation using the formula provides how much water could be adsorbed on the γ-Αΐ₂θ₃ support, e.g., 0.01 weigh percent (wt.%) at a T2 temperature of 650°C. For the TGA method, 14.52 mg of γ- AI2O₃ was used (Figure 3B) resulting in a total surface area of 2.33 m and an uptake water amount, i.e., water adsorption amount, of 1.45 x 10^" mg (e.g., 0.01 wt.% of 14.52 mg) (volume of 1.8 x 10^"3 mL and 8.1 x 10^"5 millimoles (mmol)). Therefore, 7.73 x 10^"4 mL of steam per m 2 of catalyst surface (e.g., 1.8 x 10 -^"3 mL/ 2.33 m 2 ) could be adsorbed on the surface of the catalyst to react with surface coke species under the regeneration condition (650°C). If the coke species exist as pure carbon, the ideal reaction for the regeneration using steam is C + ¾0 H₂ + CO. Therefore, if the coke amount is accurately measured, an accurate excess steam amount can be determined.

[0063] γ-Αΐ2θ₃ was prepared using boehmite precursor by calcination in air. Several characterization methods were used to verify the high surface area of y-AkCb. These experiments showed that γ-Αΐ2(¾ was much finer than α-Α1₂0₃, which results in higher water uptake capability. According to the systematic TGA measurements, it was observed that the water uptake of γ-Αΐ2θ₃ is strongly dependent on the cooling rate. This TGA approach can be applied to accurately estimate how much steam is needed to saturate the coked catalyst surfaces during the regeneration process when steam is used as an oxidant. These approaches can be used to analyze different types of catalysts, for example, an γ-Αΐ2θ₃ support coated with chromia, as in the case of chromia-based catalysts on γ-Αΐ2(¾, and measure the water uptake amount and its rate.

[0064] The methods disclosed herein include at least the following embodiments:

[0065] Embodiment 1 : A method for calculating an amount of steam to be used in a regeneration process of a catalyst, comprising: determining an amount of water adsorbed onto a surface of the catalyst using a thermogravimetric analysis; and determining the amount of steam to be used in the regeneration process of the catalyst based on the determined amount of adsorbed water.

[0066] Embodiment 2: The method of Embodiment 1, wherein the catalyst is a CATOFIN catalyst, a chromium-based catalyst, a silica-based catalyst, a zirconia-based catalyst, an alumina-based catalyst, a zeolite-based catalyst, or a combination comprising at least one of the foregoing.

[0067] Embodiment 3: The method of Embodiment 1 or Embodiment 21, wherein the catalyst is catalyzes dehydrogenation of alkanes or CATOFIN processes.

[0068] Embodiment 4: The method of any of Embodiments 1-3, wherein the thermogravimetric analysis comprises: heating the catalyst to a first temperature, Tj; cooling the catalyst from Tj to a second temperature, T2; and measuring a weight change of the catalyst from Tj to T₂, wherein the weight change is the amount of water adsorbed onto the surface of the catalyst. [0069] Embodiment 5: The method of Embodiment 4, wherein Tj is a temperature of 400°C to 800°C;

[0070] Embodiment 6: The method of Embodiment 4 or Embodiment 5, wherein T2 is a temperature of 50°C to 500°C.

[0071] Embodiment 7: The method of any of Embodiments 4-6, wherein the cooling of the catalyst to the second temperature occurs at a controlled rate of 10°C/minute.

[0072] Embodiment 8: The method of any of Embodiments 4-7, wherein the heating of the catalyst to the first temperature occurs at a controlled rate of 10°C/minute.

[0073] Embodiment 9: The method of any of Embodiments 1-8, wherein the thermogravimetric analysis comprises: heating the catalyst to a first temperature, Tj , from an initial starting temperature, To; and measuring a weight change of the catalyst from To to Tj wherein the weight change is the amount of water adsorbed onto the surface of the catalyst.

[0074] Embodiment 10: The method of Embodiment 9, wherein Tj is a temperature of 400°C to 800°C.

[0075] Embodiment 11 : The method of Embodiment 9 or Embodiment 10, wherein the heating of the catalyst to the first temperature occurs at a controlled rate of 10°C/minutes.

[0076] Embodiment 12: The methods of any of Embodiments 4-11, wherein the heating of the catalyst to Tj results in at least partial desorption of water from the catalyst.

[0077] Embodiment 13: The method of any of Embodiments 1-12, further comprising determining a surface area of the catalyst, wherein the amount of steam to be used in the regeneration process of the catalyst is calculated as a function of the surface area of the catalyst.

[0078] Embodiment 14: The method of any of Embodiments 1-13, wherein the method is performed prior to the catalyst undergoing the regeneration process.

[0079] Embodiment 15: The method of any of Embodiments 1-14, wherein the method is performed prior to the use of the catalyst in a chemical reaction.

[0080] Embodiment 16: The method of any of Embodiments 1-15, wherein the catalyst is present in an amount of 5 milligrams to 30 milligrams.

[0081] Embodiment 17: The method of any of Embodiments 1-16, wherein the thermogravimetric analysis is performed at a pressure of 101 kiloPascals.

[0082] Embodiment 18: The method of any of Embodiments 1-17, wherein the thermogravimetric analysis is performed in air.

[0083] Embodiment 19: A method for calculating an amount of steam to be used in a regeneration process of a catalyst, comprising: determining an amount of water adsorbed onto a surface of the catalyst using a thermogravimetric analysis, wherein the thermogravimetric analysis comprises heating the catalyst to a first temperature, T_l5 wherein the first temperature is 650°C; cooling the catalyst from Ti to a second temperature, T₂, wherein the second temperature is 50°C; and measuring a weight change of the catalyst from Tj to T₂, wherein the weight change is the amount of water adsorbed onto the surface of the catalyst; and determining the amount of steam to be used in the regeneration process of the catalyst based on the determined amount of adsorbed water.

[0084] Embodiment 20: The method of Embodiment 19, wherein greater than or equal to 5 x 10^"4 milliliters of steam per square meter of catalyst surface is adsorbed on the surface of the catalyst to react with surface coke species under the regeneration conditions.

[0085] In addition to the various embodiments depicted and claimed, the disclosed subject matter is also directed to other embodiments having other combinations of the features disclosed and claimed herein. As such, the particular features presented herein can he combined with each other in other manners within the scope of the disclosed subject matter such that the disclosed subject matter includes any suitable combination of the features disclosed herein. The foregoing description of specific embodiments of the disclosed subject matter has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosed subject matter to those embodiments disclosed.

[0086] It will be apparent to those skilled in the art that various modifications and variations can be made in the compositions and methods of the disclosed subject matter without departing from the spirit or scope of the disclosed subject matter. Thus, it is intended that the disclosed subject matter include modifications and variations that are within the scope of the appended claims and their equivalents. Various publications, patents and patent applications are cited herein, the contents of which are hereby incorporated by reference in their entireties.

[0087] A more complete understanding of the components, processes, and apparatuses disclosed herein can be obtained by reference to the accompanying drawings. These figures (also referred to herein as "FIG.") are merely schematic representations based on convenience and the ease of demonstrating the present disclosure, and are, therefore, not intended to indicate relative size and dimensions of the devices or components thereof and/or to define or limit the scope of the exemplary embodiments. Although specific terms are used in the description for the sake of clarity, these terms are intended to refer only to the particular structure of the embodiments selected for illustration in the drawings, and are not intended to define or limit the scope of the disclosure. In the drawings and the description, it is to be understood that like numeric designations refer to components of like function.

[0088] In general, the invention may alternately comprise, consist of, or consist essentially of, any appropriate components herein disclosed. The invention may additionally, or alternatively, be formulated so as to be devoid, or substantially free, of any components, materials, ingredients, adjuvants or species used in the prior art compositions or that are otherwise not necessary to the achievement of the function and/or objectives of the present invention. The endpoints of all ranges directed to the same component or property are inclusive and independently combinable (e.g., ranges of "less than or equal to 25 wt , or 5 wt% to 20 wt ," is inclusive of the endpoints and all intermediate values of the ranges of "5 wt% to 25 wt ," etc.). Disclosure of a narrower range or more specific group in addition to a broader range is not a disclaimer of the broader range or larger group. "Combination" is inclusive of blends, mixtures, alloys, reaction products, and the like. Furthermore, the terms "first," "second," and the like, herein do not denote any order, quantity, or importance, but rather are used to denote one element from another. The terms "a" and "an" and "the" herein do not denote a limitation of quantity, and are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. "Or" means "and/or." The suffix "(s)" as used herein is intended to include both the singular and the plural of the term that it modifies, thereby including one or more of that term (e.g., the film(s) includes one or more films). Reference throughout the specification to "one embodiment", "another embodiment", "an embodiment", and so forth, means that a particular element (e.g., feature, structure, and/or characteristic) described in connection with the embodiment is included in at least one embodiment described herein, and may or may not be present in other embodiments. In addition, it is to be understood that the described elements may be combined in any suitable manner in the various embodiments.

[0089] The modifier "about" used in connection with a quantity is inclusive of the stated value and has the meaning dictated by the context (e.g., includes the degree of error associated with measurement of the particular quantity). The notation "+ 10%" means that the indicated measurement can be from an amount that is minus 10% to an amount that is plus 10% of the stated value. The terms "front", "back", "bottom", and/or "top" are used herein, unless otherwise noted, merely for convenience of description, and are not limited to any one position or spatial orientation. "Optional" or "optionally" means that the subsequently described event or circumstance can or cannot occur, and that the description includes instances where the event occurs and instances where it does not. Unless defined otherwise, technical and scientific terms used herein have the same meaning as is commonly understood by one of skill in the art to which this invention belongs. A "combination" is inclusive of blends, mixtures, alloys, reaction products, and the like.

[0090] All cited patents, patent applications, and other references are incorporated herein by reference in their entirety. However, if a term in the present application contradicts or conflicts with a term in the incorporated reference, the term from the present application takes precedence over the conflicting term from the incorporated reference

[0091] While particular embodiments have been described, alternatives,

modifications, variations, improvements, and substantial equivalents that are or may be presently unforeseen may arise to applicants or others skilled in the art. Accordingly, the appended claims as filed and as they may be amended are intended to embrace all such alternatives, modifications variations, improvements, and substantial equivalents.

[0092] I/we claim:

Claims

CLAIMS:

1. A method for calculating an amount of steam to be used in a regeneration process of a catalyst, comprising:

determining an amount of water adsorbed onto a surface of the catalyst using a thermogravimetric analysis; and

determining the amount of steam to be used in the regeneration process of the catalyst based on the determined amount of adsorbed water.

2. The method of Claim 1 , wherein the catalyst is a CATOFIN catalyst, a chromium- based catalyst, a silica-based catalyst, a zirconia-based catalyst, an alumina-based catalyst, a zeolite-based catalyst, or a combination comprising at least one of the foregoing.

3. The method of Claim 1 or Claim 21, wherein the catalyst is catalyzes

dehydrogenation of alkanes or CATOFIN processes.

4. The method of any of Claims 1-3, wherein the thermogravimetric analysis comprises:

heating the catalyst to a first temperature, Tj;

cooling the catalyst from Tj to a second temperature, T2; and

measuring a weight change of the catalyst from Tj to T₂, wherein the weight change is the amount of water adsorbed onto the surface of the catalyst.

5. The method of Claim 4, wherein Tj is a temperature of 300°C to 800°C;

6. The method of Claim 4 or Claim 5, wherein T2 is a temperature of 50°C to 500°C.

7. The method of any of Claims 4-6, wherein the cooling of the catalyst to the second temperature occurs at a controlled rate of 10°C/minute.

8. The method of any of Claims 4-7, wherein the heating of the catalyst to the first temperature occurs at a controlled rate of 10°C/minute.

9. The method of any of Claims 1-8, wherein the thermogravimetric analysis comprises:

heating the catalyst to a first temperature, Tj , from an initial starting temperature, To; and

measuring a weight change of the catalyst from To to Tj wherein the weight change is the amount of water adsorbed onto the surface of the catalyst.

10. The method of Claim 9, wherein Tj is a temperature of 400°C to 800°C.

11. The method of Claim 9 or Claim 10, wherein the heating of the catalyst to the first temperature occurs at a controlled rate of 10°C/minutes.

12. The methods of any of Claims 4-11, wherein the heating of the catalyst to Tj results in at least partial desorption of water from the catalyst.

13. The method of any of Claims 1-12, further comprising determining a surface area of the catalyst, wherein the amount of steam to be used in the regeneration process of the catalyst is calculated as a function of the surface area of the catalyst.

14. The method of any of Claims 1-13, wherein the method is performed prior to the catalyst undergoing the regeneration process.

15. The method of any of Claims 1-14, wherein the method is performed prior to the use of the catalyst in a chemical reaction.

16. The method of any of Claims 1-15, wherein the catalyst is present in an amount of 5 milligrams to 30 milligrams.

17. The method of any of Claims 1-16, wherein the thermogravimetric analysis is performed at a pressure of 101 kiloPascals.

18. The method of any of Claims 1-17, wherein the thermogravimetric analysis is performed in air.

19. A method for calculating an amount of steam to be used in a regeneration process of a catalyst, comprising:

determining an amount of water adsorbed onto a surface of the catalyst using a thermogravimetric analysis, wherein the thermogravimetric analysis comprises

heating the catalyst to a first temperature, Tj, wherein the first temperature is

650°C;

cooling the catalyst from Tj to a second temperature, T₂, wherein the second temperature is 50°C; and

measuring a weight change of the catalyst from Ti to T₂, wherein the weight change is the amount of water adsorbed onto the surface of the catalyst; and determining the amount of steam to be used in the regeneration process of the catalyst based on the determined amount of adsorbed water.

20. The method of Claim 19, wherein greater than or equal to 5 x 10^"4 milliliters of steam per square meter of catalyst surface is adsorbed on the surface of the catalyst to react with surface coke species under the regeneration conditions.