CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority from U.S. Provisional Patent Application No. 62/044,392, filed on September 1, 2014, which is entirely incorporated by reference herein.

BACKGROUND

[0002] Pyrolytic bio-oil derived from biomass may have limited commercial applications because of poor heating value (~17 MJ/kg), high oxygen content (-45 weight %), high viscosity (>200 cP), and corrosiveness. Hydrotreatment of bio-oil in the presence of hydrogen using heterogeneous catalysts may be used to produce improved liquid hydrocarbon products such as gasoline, kerosene, and diesel fractions. Unfortunately, hydrotreatment catalysts may become deactivated due to carbon deposition from bio-oil polymerization and coke formation.

[0003] Desulfurization catalysts such as CoMo/alumina and NiMo/alumina are commonly used with crude oil, typically with much lower acidity (pH>4), negligible water (<1%), and low oxygen content (< 2%) compared to bio-oil, which may have pH -2.5, 20- 30% water, and 30-45% oxygen. When these catalysts are used to deoxygenate bio-oil, a large amount of water may be produced, and the catalysts may be quickly deactivated due to coke formation and/or decomposition of alumina.

[0004] Active metal catalysts such as Pd/C, Pt/C, Ru/C, and Ru/Ti0 ₂ perform well for deoxygenating and stabilizing bio-oil, but may deactivate too quickly to be commercially viable.

[0005] Catalysts may be regenerated to remove deactivating carbon, for example, by burning coke with steam above 600 °C, but such conditions may sinter the active metal and corrode the reactor. Deposited carbon may also be reacted with oxygen to produce CO ₂ . This exothermic reaction may need low oxygen concentration and temperatures < 500 °C to avoid sintering the active metal, along with reactor flushing with inert gas to avoid catastrophic hydrogen/oxygen combustion or explosion. Deposited carbon may also be reacted with hydrogen. This reaction is slightly exothermic, yet may lead to reduced sintering of active metals compared to oxidative conditions.

[0006] The present application appreciates that managing catalysts for hydrotreatment of bio-oil may be a challenging endeavor.

SUMMARY

[0007] In one embodiment, a method for catalyst regeneration is provided. The method may include providing a hydrotreatment process. The hydrotreatment process may include contacting a flow of bio-oil and a flow of hydrogen to at least one catalyst. The hydrotreatment process may deposit carbon on the at least one catalyst effective to cause at least partial deactivation of a catalytic activity of the at least one catalyst. The method may include treating the deposited carbon on the at least one catalyst effective to remove at least a portion of the deposited carbon from the at least one catalyst. The treating may include contacting the deposited carbon on the at least one catalyst with one or more of a solvent and hydrogen. The treating may regenerate at least a portion of the catalytic activity of the at least one catalyst.

[0008] In another embodiment, a method for catalyst regeneration is provided. The method may include contacting a flow of bio-oil and a flow of hydrogen to at least one catalyst in a hydrotreatment process. The hydrotreatment process may deposit carbon on the at least one catalyst effective to cause at least partial deactivation of a catalytic activity of the at least one catalyst. The method may include determining a regeneration indicator. The regeneration indicator may correspond to a presence of the deposited carbon on the at least one catalyst. The regeneration indicator may correspond to the at least partial deactivation of the catalytic activity of the at least one catalyst. The method may include cooling the at least one catalyst to below a boiling temperature of a polar organic solvent. The method may include treating the deposited carbon on the at least one catalyst effective to remove at least a portion of the deposited carbon from the at least one catalyst and regenerate at least a portion of the catalytic activity of the at least one catalyst. The treating may include contacting the deposited carbon on the at least one catalyst with the polar organic solvent below the boiling temperature of the polar organic solvent. The treating may include contacting the deposited carbon on the at least one catalyst with hydrogen and heating the at least one catalyst and the hydrogen together at a temperature of between about 200 °C and about 450 °C. The method may include resuming the hydrotreatment process by contacting the flow of bio-oil and the flow of hydrogen to the at least one catalyst after treating the deposited carbon on the at least one catalyst.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The accompanying figures, which are incorporated in and constitute a part of the specification, illustrate example methods and apparatuses, and are used merely to illustrate example embodiments.

[0010] FIG. 1 is a flow diagram of an example method 100 for catalyst regeneration.

[0011] FIG. 2 is a flow diagram of an example method 200 for catalyst regeneration.

[0012] FIG. 3 shows TABLE 1, describing reaction conditions and liquid product yields for EXAMPLE 1.

[0013] FIG. 4 shows TABLE 2, describing physical properties of liquid product for EXAMPLE 2. [0014] FIG. 5 shows TABLE 3, describing elemental composition, acidity and energy value of the organic phase and bio-oil for EXAMPLE 2.

[0015] FIG. 6 shows TABLE 4, summarizing cleaning procedures detailed in EXAMPLE 3.

[0016] FIG. 7 shows TABLE 5, describing metal dispersion and surface area values for fresh and spent catalysts of EXAMPLE 4.

[0017] FIG. 8 is a bar graph showing % weight loss in air (700 °C) for reducing fresh catalyst and spent catalyst for run 1 of EXAMPLE 5.

[0018] FIG. 9 is a bar graph showing % weight loss in air (700 °C) for reducing fresh catalyst and spent catalyst for run 2 of EXAMPLE 5.

[0019] FIG. 10 is a bar graph showing % weight loss in air (700 °C) for reducing fresh catalyst and spent catalyst for run 3 of EXAMPLE 5.

DETAILED DESCRIPTION

[0020] FIG. 1 depicts an example method 100 for catalyst regeneration. In various embodiments, method 100 may include 102 providing a hydrotreatment process. The hydrotreatment process may include contacting a flow of bio-oil and a flow of hydrogen to at least one catalyst. The hydrotreatment process may deposit carbon on the at least one catalyst effective to cause at least partial deactivation of a catalytic activity of the at least one catalyst.

Method 100 may include 104 treating the deposited carbon on the at least one catalyst effective to remove at least a portion of the deposited carbon from the at least one catalyst.

The treating may include contacting the deposited carbon on the at least one catalyst with one or more of a solvent and hydrogen. The treating may regenerate at least a portion of the catalytic activity of the at least one catalyst. In some embodiments, the treating the deposited carbon on the at least one catalyst may include contacting the deposited carbon on the at least one catalyst with the solvent and the hydrogen effective to remove at least a portion of the deposited carbon from the at least one catalyst. The method may include providing the flow of bio-oil by pyrolyzing biomass. The method may include providing the flow of bio-oil in the form of one or more of vapor and liquid.

[0021] In some embodiments, the treating the deposited carbon on the at least one catalyst may include contacting the deposited carbon on the at least one catalyst with the solvent, e.g., by rinsing the at least one catalyst with an organic solvent. The method may include cooling the at least one catalyst to below the boiling temperature of the solvent. The cooling the at least one catalyst to below the boiling temperature of the solvent may include contacting the hydrogen or an inert gas to the at least one catalyst. The hydrogen or the inert gas may be at a temperature below the boiling temperature of the solvent. The solvent may include a polar organic liquid, e.g., a protic organic solvent, e.g., an alcohol. The solvent may include one or more polar organic liquids, such as alcohols, ketones, polar ethers, esters, amides, nitriles, and the like. For example, the solvent may include one or more of: methanol, ethanol, 2-propanol, w-butanol, seobutanol, tert-butanol, pentanol, hexanol, methyl cyclohexanol, acetone, methyl ethyl ketone, butanone, ethyl acetate, tetrahydrofuran, methyl tert-butyl ether, diethyl ether, acetonitrile, dimethyl formamide, N-methyl pyrrolidone, and the like. The treating the deposited carbon on the at least one catalyst may include contacting the deposited carbon on the at least one catalyst with the solvent at a pressure below a pressure of the hydrotreatment process.

[0022] The method may include regenerating the catalyst by contacting the at least one catalyst with hydrogen at a temperature in °C of about one or more of: 250 to 550, 300 to 500, 325 to 475, 350 to 450, 375 to 425, and 400. For example, the hydrogen may chemically reduce carbon accumulation on the at least one catalyst to produce gaseous methane. Such reducing may be desirable compared to oxidative methods of removing carbon, because hydrogen reduction of carbon to methane may be less exothermic than carbon oxidation in the presence of oxygen, leading to less heating and less thermal damage to the stabilizing catalyst, e.g., by sintering.

[0023] In some embodiments, the method may include diluting the bio-oil in the organic solvent, e.g., a polar organic solvent, to form a diluted bio-oil. The organic solvent may include a protic organic solvent, e.g., an alcohol. The method may include contacting the diluted bio-oil to the at least one catalyst. The method may include removing at least a portion of the organic solvent from the diluted bio-oil after contacting the at least one catalyst. The removed organic solvent may be recycled. The organic solvent may include one or more of: methanol, ethanol, 2-propanol, w-butanol, seobutanol, tert-butanol, pentanol, hexanol, methyl cyclohexanol, acetone, methyl ethyl ketone, butanone, ethyl acetate, tetrahydrofuran, methyl tert-butyl ether, acetonitrile, dimethyl formamide, and N-methyl pyrrolidone. Diluting the bio-oil in the organic solvent may include diluting the bio-oil to a percentage by weight of the organic solvent of about one or more of: 5 to 50, 10 to 45, 15 to 40, 20 to 35, 25 to 35, and 30.

[0024] In several embodiments, treating the deposited carbon on the at least one catalyst may include contacting the deposited carbon on the at least one catalyst with the hydrogen. The treating may include heating the at least one catalyst and the hydrogen together at a temperature in °C of about one of: 200, 210, 220, 230, 240, 250, 260, 270, 280, 290, 300, 310, 320, 330, 340, 350, 360, 370, 380, 390, 400, 410, 420, 430, 440, or 450, e.g., about 380 °C, or a range between any two of the preceding values, e.g., between about 200 °C and about 450 °C.

[0025] In some embodiments, the treating may include providing the hydrogen to the at least one catalyst at a pressure in pounds per square inch gage (psig) of about one of: 0.01, 0.1, 1, 10, 50, 100, 200, 250, 500, 750, 1000, 1250, 1500, 1750, or 2000, e.g., about 100 psig, or a range between any two of the preceding values, for example, between about 0.01 psig and about 2000 psig. The corresponding gauge pressures in kilopascals (kPa) may be about one of: 0.07, 0.7, 7, 70, 340, 700, 1400, 1700, 3400, 5100, 7000, 8600, 10,000, 12,000, or 14,000, e.g., about 700 kPa gauge, or a range between any two of the preceding values, for example, between about 0.07 kPa gauge and about 14,000 kPa gauge.

[0026] In several embodiments, the method may include flushing the at least one catalyst with an inert gas. The inert gas may include one or more of: nitrogen, carbon dioxide, helium, neon, argon, and krypton.

[0027] In various embodiments, the method may include reducing the flow of bio-oil to the hydrotreatment process prior to treating the deposited carbon on the at least one catalyst. The method may include stopping the flow of bio-oil to the hydrotreatment process prior to treating the deposited carbon on the at least one catalyst. The method may include reducing the flow of hydrogen to the hydrotreatment process prior to treating the deposited carbon on the at least one catalyst. The method may include maintaining the flow of hydrogen to the hydrotreatment process while treating the deposited carbon on the at least one catalyst.

[0028] In some embodiments, the providing the hydrotreatment process may include conducting the hydrotreatment process by contacting the flow of bio-oil and the flow of hydrogen to the at least one catalyst. The method may include resuming conducting the hydrotreatment process by contacting the flow of bio-oil and the flow of hydrogen to the at least one catalyst after treating the deposited carbon on the at least one catalyst.

[0029] In several embodiments, the at least one catalyst, e.g., one or more catalysts, two or more catalysts, and the like, may include a desulfurization catalyst. The at least one catalyst may include an active metal catalyst. The at least one catalyst may include one or more of: cobalt (Co), molybdenum (Mo), nickel (Ni), titanium (Ti), tungsten (W), zinc (Zn), antimony (Sb), bismuth (Bi), cerium (Ce), vanadium (V), niobium (Nb), tantalum (Ta), chromium (Cr), manganese (Ma), rhenium (Re), iron (Fe), platinum (Pt), iridium (Ir), palladium (Pd), osmium (Os), rhodium (Rh), gold (Au), ruthenium (Ru), copper impregnated zinc oxide (Cu/ZnO), copper impregnated chromium oxide (Cu/Cr), nickel aluminum oxide ( 1/AI2O ₃ ), palladium aluminum oxide (PdA^C^), cobalt molybdenum (C0M0), nickel molybdenum (NiMo), nickel molybdenum tungsten (NiMoW), sulfided cobalt molybdenum (C0M0), sulfided nickel molybdenum (NiMo ), and a metal carbide. The at least one catalyst may include a metal oxide support such as a titanium oxide or titania support (e.g., T1O2), a silicon oxide or silica support (e.g., S1O2), a zirconium oxide or zirconia (e.g., ZrC^) support, a niobium oxide (e.g., Nb ₂ Os) support, an aluminum oxide or alumina support (e.g., AI2O ₃ ), a support including one or more mixtures of non-alumina metal oxides, a zeolite, e.g., ZSM5 type, Zeolite Y type, mesoporous material (e.g., MCM type), and the like (Zeolyst International, Conshohocken, PA). The hydrotreatment catalyst may include a noble metal composition on the metal oxide support. The noble metal composition may include one or more noble metals, such as: rhodium (Rh), palladium (Pd), gold (Au), ruthenium (Ru), and the like.

[0030] In various embodiments, treating the deposited carbon on the at least one catalyst may be effective to remove a percentage by weight of the deposited carbon on the at least one catalyst of one or more of about: 80%, 90%, 95%, 96%, 97%, 98%, 99%, 99.1%, 99.2%, 99.3%, 99.4%, 99.5%, 99.6%, 99.7%, 99.8%, 99.9%, 99.95%, and 99.99%, e.g., at least about 95%, or a range between any two of the preceding values, e.g., between about 80% and about 99.99%. The at least one catalyst may be characterized by an initial catalytic activity prior to the hydrotreatment process depositing carbon on the at least one catalyst. Treating the deposited carbon on the at least one catalyst may be effective to regenerate the at least one catalyst to a percentage of the initial catalytic activity of one or more of about: 80%, 90%, 95%, 96%, 97%, 98%, 99%, 99.1%, 99.2%, 99.3%, 99.4%, 99.5%, 99.6%, 99.7%, 99.8%, 99.9%, 99.95%, and 99.99%, e.g., at least about 95%, or a range between any two of the preceding values, e.g., between about 80% and about 99.99%.

[0031] In some embodiments, the at least one catalyst may be characterized by an initial metal dispersion prior to the hydrotreatment process depositing carbon on the at least one catalyst. The at least one catalyst may be characterized by a metal dispersion after treating the deposited carbon on the at least one catalyst at a percentage of the initial metal dispersion of one or more of about: 50%, 60%, 70%, 80%, 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, 99.9%, 99.95%, or 99.99%%, e.g., at least about 50%, or a range between any two of the preceding values, e.g., between about 50% and about 99.99%. Treating the deposited carbon on the at least one catalyst may be conducted by substantially avoiding sintering or agglomerating the at least one catalyst. Treating the deposited carbon on the at least one catalyst may be conducted without causing a hot-spot reaction in the at least one catalyst.

[0032] In several embodiments, the treating the deposited carbon on the at least one catalyst may be conducted or initiated upon determining a regeneration indicator. A regeneration indicator may include a change in one or more of: volume, mass, concentration, state, density, turnover rate, turnover number, temperature, and the like, of one or more components or parameters in a reaction mixture to indicate that the at least one catalyst may be at least partially deactivated. A regeneration indicator may include a comparison between a value or an amount achievable while employing a fresh, unused catalyst, with a value or an amount achieved as the reaction progresses and the at least one catalyst becomes at least partially deactivated. A regeneration indicator may include a comparison between an input value or amount and an output value or amount. An undesired value or amount achieved as the reaction progresses may be referred to as a regeneration threshold indicating regeneration of the catalyst may be desirable.

[0033] The regeneration indicator may correspond to a presence of the deposited carbon on the at least one catalyst. The regeneration indicator may correspond to the at least partial deactivation of the catalytic activity of the at least one catalyst. Determining the regeneration indicator may include comparing a run time value of the hydrotreatment process to a regeneration threshold run time value, e.g., a progressively longer run time value may indicate a lower turnover rate or turnover number of the at least one catalyst. Determining the regeneration indicator may include comparing an amount of hydrogen added to the hydrotreatment process to a regeneration threshold amount of hydrogen, e.g., increasing amounts of hydrogen output may indicate that the hydrogen is increasingly not being readily consumed during the hydrotreatment process.. Determining the regeneration indicator may include comparing an amount of bio-oil added to the hydrotreatment process to a regeneration threshold amount of bio-oil, e.g., increasing amounts of bio-oil output may indicate that the bio-oil is increasingly not being readily consumed during the hydrotreatment process. Determining the regeneration indicator may include comparing a mass flow input value to the hydrotreatment process to a regeneration threshold mass flow input value. Determining the regeneration indicator may include comparing an amount of product output from the hydrotreatment process to a regeneration threshold amount of product output, e.g., decreasing amounts of product output may indicate that the bio-oil is increasingly not being readily consumed during the hydrotreatment process. Determining the regeneration indicator may include comparing a mass flow output value from the hydrotreatment process to a regeneration threshold mass flow output value. Determining the regeneration indicator may include detecting the carbon deposited on the at least one catalyst by one or more of: spectroscopy, electrical conductivity, thermal conductivity, visual inspection, temperature programmed oxidation, temperature programmed reduction, thermogravimetric analysis, and the like.

[0034] In various embodiments, the hydrotreatment process may output a light organic liquid phase product. Determining the regeneration indicator may include determining a density of the light organic phase is greater than or equal to a regeneration threshold density of the light organic phase, i.e., a lower density organic liquid phase may indicate that the bio- oil is not readily being consumed during the hydrotreatment process. The regeneration threshold density of the light organic liquid phase may be a value in g/cm ³ of about one of: 0.77, 0.78, 0.79, 0.8, 0.81, 0.82, 0.83, 0.84, 0.85, 0.86, 0.87, 0.88, 0.89, 0.9, 0.91, 0.92, 0.93, 0.94, or 0.95. The hydrotreatment process may output an aqueous phase. Determining the regeneration indicator may include determining a pH of the aqueous phase is less than or equal to a regeneration threshold pH of the aqueous phase. The regeneration threshold pH of the aqueous phase may be about one of: 1 1, 10, 9, 8, 7.5, 7.4, 7.3, 7.2, 7.1, 7.0, 6.9, 6.8, 6.7, 6.6, 6.5, 6, 5, 4, or 3.

[0035] In some embodiments, determining the regeneration indicator may include determining an amount of unconsumed hydrogen exiting the hydrotreatment process is equal to or greater than a regeneration threshold amount of unconsumed hydrogen. The regeneration threshold amount of unconsumed hydrogen may correspond to detection of any unconsumed hydrogen exiting the hydrotreatment process. The regeneration threshold amount of unconsumed hydrogen may be a ratio of unconsumed hydrogen to hydrogen added to the hydrotreatment process. The ratio may be about one or more of 1 : 100, 1 : 1000, 1 : 10,000, and 1 : 100,000.

[0036] The one or more catalysts may be regenerated when methane production during regeneration with hydrogen may fall by one or more of: 50%, 60%, 70%, 80%, 90%, 95%, 96%, 97%, 98%, and 99%, e.g., by at least about 90%. In some embodiments, determining the regeneration indicator may include determining an amount or rate of methane exiting the hydrotreatment process is equal to or greater than a regeneration threshold amount, e.g., 1 ppm, 2 ppm, 3 ppm, 4 ppm, 5 ppm, or 10 ppm.

[0037] In several embodiments, determining the regeneration indicator may include determining a pressure differential across the at least one catalyst that is equal to or greater than a regeneration threshold pressure differential. The regeneration threshold pressure differential may be greater than about ±1%, 2%, 3%, 4%, or 5%. Determining the regeneration indicator may include determining a hydrogen pressure or flow variation at an input of the hydrotreatment process that is equal to or greater than a regeneration threshold hydrogen pressure or flow variation. The regeneration threshold hydrogen pressure or flow variation may be greater than about ±1%, 2%, 3%, 4%, or 5%.

[0038] In various embodiments, the determining the regeneration indicator may include determining a temperature decrease corresponding to a decrease in an exothermic reaction on the at least one catalyst. The temperature decrease may be a value in °C of at least about one or more of: 1, 5, 10, 15, 20, 25, 50, 75, and 100.

[0039] In some embodiments, the determining the regeneration indicator may include visually or spectroscopically determining a color change in an organic phase output from the hydrotreatment process. Determining the regeneration indicator may include determining an increase in a total acid number of an organic phase output from the hydrotreatment process. The determining the regeneration indicator may include determining a total acid number in mg KOH/gram of an organic phase output from the hydrotreatment process of equal or greater than one or more of: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 1 1, 12, 13, 14, 15, 20, and 25. [0040] In some embodiments the determining the regeneration indicator may include determining a decrease in an energy value of an organic phase output from the hydrotreatment process. The determining the regeneration indicator may include determining an increase in an oxygen content value of an organic phase output from the hydrotreatment process. The oxygen content value of the organic phase output from the hydrotreatment process may be a weight percent of the organic phase of equal to or greater than one or more of about 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%. 0.7%. 0.8%, 0.9%, 1%, 2%, 3%, 4%, 5%, and 10%.

[0041] FIG. 2 depicts an example method 200 for catalyst regeneration. In various embodiments, method 200 may include 202 contacting a flow of bio-oil and a flow of hydrogen to at least one catalyst in a hydrotreatment process. The hydrotreatment process may deposit carbon on the at least one catalyst effective to cause at least partial deactivation of a catalytic activity of the at least one catalyst. The method may include 204 determining a regeneration indicator. The regeneration indicator may correspond to a presence of the deposited carbon on the at least one catalyst. The regeneration indicator may correspond to the at least partial deactivation of the catalytic activity of the at least one catalyst. The method may include 206 cooling the at least one catalyst to below a boiling temperature of a polar organic solvent. The method may include 208 treating the deposited carbon on the at least one catalyst effective to remove at least a portion of the deposited carbon from the at least one catalyst and regenerate at least a portion of the catalytic activity of the at least one catalyst. The treating may include 208a contacting the deposited carbon on the at least one catalyst with the polar organic solvent below the boiling temperature of the polar organic solvent. The treating may include 208b contacting the deposited carbon on the at least one catalyst with hydrogen and heating the at least one catalyst and the hydrogen together at a temperature of between about 200 °C and about 450 °C. The method may include 210 resuming the hydrotreatment process by contacting the flow of bio-oil and the flow of hydrogen to the at least one catalyst after treating the deposited carbon on the at least one catalyst.

[0042] In various embodiments, method 200 may include any of the elements described herein for method 100.

[0043] In various embodiments, the cooling the at least one catalyst to below the boiling temperature of the polar organic solvent may include contacting the hydrogen or an inert gas to the at least one catalyst. The hydrogen or the inert gas may be at a temperature below the boiling temperature of the solvent, e.g., the polar organic solvent. The polar organic solvent may include alcohols, ketones, polar ethers, esters, amides, nitriles, and the like. For example, the solvent may include one or more of: methanol, ethanol, 2-propanol, n-butanol, sec-butanol, tert-butanol, pentanol, hexanol, acetone, methyl ethyl ketone, butanone, ethyl acetate, tetrahydrofuran, methyl tert-butyl ether, diethyl ether, acetonitrile, dimethyl formamide, N-methyl pyrrolidone, and the like. The treating the deposited carbon on the at least one catalyst may include contacting the deposited carbon on the at least one catalyst with the polar organic solvent at a pressure below a pressure of the hydrotreatment process.

[0044] In some embodiments, the treating may include providing the hydrogen to the at least one catalyst at a pressure in psig of about one of: 0.01, 0.1, 1, 10, 50, 100, 200, 250, 500, 750, 1000, 1250, 1500, 1750, or 2000, e.g., about 100 psig, or a range between any two of the preceding values, for example, between about 0.01 psig and about 2000 psig. The corresponding gauge pressures in kilopascals (kPa) may be about one of: 0.07, 0.7, 7, 70, 340, 700, 1400, 1700, 3400, 5100, 7000, 8600, 10,000, 12,000, or 14,000, e.g., about 700 kPa gauge, or a range between any two of the preceding values, for example, between about 0.07 kPa gauge and about 14,000 kPa gauge. [0045] In several embodiments, the method may include flushing the at least one catalyst with an inert gas, e.g., nitrogen, carbon dioxide, helium, neon, argon, or krypton.

[0046] In some embodiments, the method may include reducing the flow of bio-oil to the hydrotreatment process prior to treating the deposited carbon on the at least one catalyst. The method may include stopping the flow of bio-oil to the hydrotreatment process prior to treating the deposited carbon on the at least one catalyst. The method may include maintaining the flow of hydrogen to the hydrotreatment process while treating the deposited carbon on the at least one catalyst.

[0047] In several embodiments, the at least one catalyst, e.g., one or more catalysts, two or more catalysts, and the like, may include a desulfurization catalyst. The at least one catalyst may include an active metal catalyst. The at least one catalyst may include one or more of: Co, Mo, Ni, Ti, W, Zn, Sb, Bi, Ce, V, Nb, Ta, Cr, Mn, Re, Fe, Pt, Ir, Pd, Os, Rh, Ru, Ru/Ti0 ₂ , Cu/ZnO, Cu/Cr, Ni/Al ₂ 0 ₃ , PdAl ₂ 0 ₃ , CoMo, NiMo, NiMoW, sulfided CoMo, sulfided NiMo, a metal carbide, and the like. The at least one catalyst may include or be deposited on a support. The support may include one or more of: a titanium oxide, a silicon oxide, a zirconium oxide, a niobium oxide, an aluminum oxide, a zeolite, and one or more mixtures of non-alumina metal oxides.

[0048] In various embodiments, the treating the deposited carbon on the at least one catalyst may be effective to remove a percentage by weight of the deposited carbon on the at least one catalyst of one or more of about: 80%, 90%, 95%, 96%, 97%, 98%, 99%, 99.1%, 99.2%, 99.3%, 99.4%, 99.5%, 99.6%, 99.7%, 99.8%, 99.9%, 99.95%, and 99.99%, e.g., at least about 95%, or a range between any two of the preceding values, e.g., between about 80% and about 99.99%. The at least one catalyst may be characterized by an initial catalytic activity prior to the hydrotreatment process depositing carbon on the at least one catalyst. The treating the deposited carbon on the at least one catalyst may be effective to regenerate the at least one catalyst to a percentage of the initial catalytic activity of one or more of about: 80%, 90%, 95%, 96%, 97%, 98%, 99%, 99.1%, 99.2%, 99.3%, 99.4%, 99.5%, 99.6%, 99.7%, 99.8%, 99.9%, 99.95%, and 99.99%, e.g., at least about 95%, or a range between any two of the preceding values, e.g., between about 80% and about 99.99%.

[0049] In some embodiments, the at least one catalyst may be characterized by an initial metal dispersion prior to the hydrotreatment process depositing carbon on the at least one catalyst. The at least one catalyst may be characterized by a metal dispersion after treating the deposited carbon on the at least one catalyst at a percentage of the initial metal dispersion of one or more of about: 50%, 60%, 70%, 80%, 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, 99.9%, 99.95%, and 99.99%%, e.g., at least about 50%, or a range between any two of the preceding values, e.g., between about 50% and about 99.99%. The treating the deposited carbon on the at least one catalyst may be conducted substantially avoiding sintering or agglomerating the at least one catalyst. The treating the deposited carbon on the at least one catalyst may be conducted without causing a hot-spot reaction in the at least one catalyst.

[0050] In several embodiments, the regeneration indicator may correspond to a presence of the deposited carbon on the at least one catalyst. The regeneration indicator may correspond to the at least partial deactivation of the catalytic activity of the at least one catalyst. Determining the regeneration indicator may include comparing a run time value of the hydrotreatment process to a regeneration threshold run time value. Determining the regeneration indicator may include comparing an amount of hydrogen added to the hydrotreatment process to a regeneration threshold amount of hydrogen. Determining the regeneration indicator may include comparing an amount of bio-oil added to the hydrotreatment process to a regeneration threshold amount of bio-oil. Determining the regeneration indicator may include comparing a mass flow input value to the hydrotreatment process to a regeneration threshold mass flow input value. Determining the regeneration indicator may include comparing an amount of product output from the hydrotreatment process to a regeneration threshold amount of product output. Determining the regeneration indicator may include comparing a mass flow output value from the hydrotreatment process to a regeneration threshold mass flow output value. Determining the regeneration indicator may include detecting the carbon deposited on the at least one catalyst by one or more of: spectroscopy, electrical conductivity, thermal conductivity, visual inspection, temperature programmed oxidation, temperature programmed reduction, thermogravimetric analysis, and the like.

[0051] In various embodiments, the hydrotreatment process may output a light organic liquid phase product. Determining the regeneration indicator may include determining a density of the light organic phase is greater than or equal to a regeneration threshold density of the light organic phase. The regeneration threshold density of the light organic liquid phase may be a value in g/cm ³ of about one of: 0.77, 0.78, 0.79, 0.8, 0.81, 0.82, 0.83, 0.84, 0.85, 0.86, 0.87, 0.88, 0.89, 0.9, 0.91, 0.92, 0.93, 0.94, or 0.95. The hydrotreatment process may output an aqueous phase. Determining the regeneration indicator may include determining a pH of the aqueous phase is less than or equal to a regeneration threshold pH of the aqueous phase. The regeneration threshold pH of the aqueous phase may be about one of: 11, 10, 9, 8, 7.5, 7.4, 7.3, 7.2, 7.1, 7.0, 6.9, 6.8, 6.7, 6.6, 6.5, 6, 5, 4, and 3.

[0052] In some embodiments, determining the regeneration indicator may include determining an amount of unconsumed hydrogen exiting the hydrotreatment process is equal to or greater than a regeneration threshold amount of unconsumed hydrogen. The regeneration threshold amount of unconsumed hydrogen may correspond to detection of any unconsumed hydrogen exiting the hydrotreatment process. The regeneration threshold amount of unconsumed hydrogen may be a ratio of unconsumed hydrogen to hydrogen added to the hydrotreatment process. The ratio may be about one or more of 1 : 100, 1 : 1000, 1 : 10,000, and 1 : 100,000.

[0053] In some embodiments, determining the regeneration indicator may include determining an amount or rate of methane exiting the hydrotreatment process is equal to or greater than a regeneration threshold amount, e.g., 1 ppm, 2 ppm, 3 ppm, 4 ppm, 5 ppm, or 10 ppm.

[0054] In several embodiments, the determining the regeneration indicator may include determining a pressure differential across the at least one catalyst that is equal to or greater than a regeneration threshold pressure differential. The regeneration threshold pressure differential may be greater than about ±1%, 2%, 3%, 4%, or 5%. Determining the regeneration indicator may include determining a hydrogen pressure or flow variation at an input of the hydrotreatment process that is equal to or greater than a regeneration threshold hydrogen pressure or flow variation. The regeneration threshold hydrogen pressure or flow variation may be greater than about ±1%, 2%, 3%, 4%, or 5%.

[0055] In various embodiments, the determining the regeneration indicator may include determining a temperature decrease corresponding to a decrease in an exothermic reaction on the at least one catalyst. The temperature decrease may be a value in °C of at least about one or more of: 1, 5, 10, 15, 20, 25, 50, 75, and 100. Determining the regeneration indicator may include visually or spectroscopically determining a color change in an organic phase output from the hydrotreatment process.

[0056] In some embodiments, determining the regeneration indicator may include determining an increase in a total acid number of an organic phase output from the hydrotreatment process. Determining the regeneration indicator may include determining a total acid number in mg KOH/gram of an organic phase output from the hydrotreatment process of equal or greater than one or more of: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 1 1, 12, 13, 14, 15, 20, and 25.

[0057] In some embodiments, determining the regeneration indicator may include determining a decrease in an energy value of an organic phase output from the hydrotreatment process. Determining the regeneration indicator may include determining an increase in an oxygen content value of an organic phase output from the hydrotreatment process. The oxygen content value of the organic phase output from the hydrotreatment process may be a weight percent of the organic phase of equal to or greater than one or more of about 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%. 0.7%. 0.8%, 0.9%, 1%, 2%, 3%, 4%, 5%, and 10%.

EXAMPLES EXAMPLE 1: Hydrotreatment of bio-oil

[0058] Hydrotreatment of bio-oil produced by pyrolysis of sawdust was performed in a trickle bed reactor with two zones. Zone I was charged with Ru/Ti0 ₂ . Zone II was loaded with Ru/Ti0 ₂ -ZSM5. Prior to hydrotreatment, the catalyst was reduced in situ at a temperature of 300 °C, i.e. treated with hydrogen. The temperature of Zone I was adjusted to 160 °C and Zone II was adjusted to 320 °C. The reaction was run with LHSV=1 (Liquid Hourly Space Velocity) and a hydrogen:bio-oil standard volumetric ratio of 4000. Four runs were performed. FIG. 3 shows TABLE 1, which summarizes the reaction conditions and yields obtained. For all runs, two phases were produced, with bio-oil yield around 50% and organic phase selectivity of about 50%. EXAMPLE 2: Liquid Product Characterization

[0059] During hydrotreatment, pH, density, and water content in the product organic phase were monitored. FIG. 4, TABLE 2 shows that as TOS (Time On Stream) progresses, the density of the product organic phase increases, corresponding to catalyst deactivation. The pH of the product organic phase increases from pH 2.5 in the starting bio-oil to more than pH 7 in the product after effective hydrotreatment.

[0060] FIG. 5, TABLE 3 presents the elemental composition of the initial bio-oil and the product organic phase. The total acid number (TAN) decreases from around 109 mg KOH/gram of bio-oil sample to less than 5 mg KOH/gram of product sample. The energy value increases approximately 70% to 90%. Both the water and oxygen weight percent decreased dramatically to less than 1% with hydrotreatment. FIG. 5, TABLE 3 demonstrates the catalytic hydrotreatment conversion of the initial bio-oil to a higher value product. FIG. 5, TABLE 3 also indicates that some deactivation of the catalyst begins to occur as indicated by oxygen concentration increasing with TOS.

EXAMPLE 3: In situ catalyst cleaning

[0061] After 6 h TOS at LHSV=1, there was noticeable catalyst deactivation due to carbon deposition. At this point, hydrotreatment was stopped and solvent rinsing was examined. Four solvents were used. FIG. 6, TABLE 4 summarizes the clearing procedure used after each run described below.

[0062] Run 1 : The reactor was cooled to room temperature, depressurized to atmospheric pressure and flushed with acetone starting with a flow rate of 0.5 mL/min and increasing to 20 mL/min. The cleaning was monitored by the change of acetone color. In the beginning of the rinse, the used acetone was dark brown. As cleaning progressed, the acetone became less dark and finally turned to a transparent yellow. After the acetone rinse, the catalyst was flushed with 2 at a flow rate of 4 L/min for a period of 30 min to remove the acetone. Subsequently, the catalyst was unloaded carefully from the reactor, paying close attention in keeping the three catalyst zones separated. Effective rinsing, such as acetone in this example, makes the catalyst significantly easier to remove from the reactor. Runs without effective solvent rinsing required extreme measures, including drills and chisels to unload the catalyst from the reactor.

[0063] Run 2: Zone II was cooled to 170 °C and decreased to atmospheric pressure. The catalyst was flushed with N-methyl pyrrolidone (ΝΜΡ), starting with a flow rate of 0.5 mL/min and increasing to 20 mL/min. The rinsing was monitored by the change of the ΝΜΡ rinse from dark brown in the beginning of the rinse to transparent yellow. The catalyst was subsequently flushed with 2 at a flow rate of 4 L/min for 30 min prior to carefully unloading the catalyst.

[0064] Run 3: The catalyst was kept at reaction temperature, depressurized to atmospheric pressure, and then flushed with diesel starting with a flow rate of 0.5 mL/min, increasing to 20 mL/min. The rinsing was monitored by the change of the diesel rinse color from dark brown in the beginning of the rinse to transparent yellow. The catalyst was subsequently flushed with 2 at a flow rate of 4 L/min for 30 min prior to carefully unloading the catalyst.

[0065] Run 4: Catalyst was kept at reaction temperature, at reaction pressure, and under hydrogen flow while it was flushed with methanol, which started at a low flow rate of 0.1 mL and was increased to 2 mL/min. At 2 mL/min methanol flow, exothermic reaction started taking place in Zone I and a hot spot of 600 °C was recorded. The methanol injection was stopped immediately and the reactor was cooled down rapidly by shutting down heaters, removing the insulation, and increasing the flow of hydrogen. Once the temperature was below 150 °C, re-injection of methanol was restarted at 0.1 m/min and was increased up to 40 mL/min within a period of 1 h, without decreasing the pressure or stopping the hydrogen flow. The rinsing was monitored by the change of the methanol rinse color from dark brown in the beginning of the rinse to transparent yellow. The reactor was brought to room pressure and temperature and flushed with 2 for 1 h before opening to atmosphere and carefully unloading the catalyst.

EXAMPLE 4: Catalyst characterization of metal dispersion with hydrogen chemisorption

[0066] FIG. 7, TABLE 5 summarizes metal dispersion and surface area for fresh and used catalyst. The metal dispersion was measured by hydrogen chemisorption. The catalysts were reduced, i.e. treated with hydrogen, for a period of 6 h at 400 °C before hydrogen adsorption at room temperature. The results demonstrate that cleaning the catalyst with acetone (room temperature, 15 psig or 100 kPa) or diesel (300 °C, 15 psig or 100 kPa) has no impact on the metal dispersion and cleaning with methanol at high temperature (300 °C), high pressure (1700 psig or 12,000 kPa) and in the presence of hydrogen sintered the catalyst in Zone I (hot spot up to 700 °C) with a decrease in metal dispersion from 8 % to 4.4%. Cleaning the catalyst with NMP (100-170 °C, 15 psig or 100 kPa) decreased metal dispersion from 8 and 8.9 to 5.3 and 4.2 respectively for Zones I and II. These surprising results show the best results were obtained by rinsing the catalyst with a polar organic solvent, such as methanol, at low temperature to remove deposited carbon and avoid exothermic reactions.

EXAMPLE 5: Catalyst characterization with thermogravimetric analysis.

[0067] FIGS. 8, 9, and 10 show the amount of material lost during oxidation in air (from 120 °C to 700 °C), from reduction of fresh catalysts (at 400 °C with H ₂ ), from spent catalysts and reduction of spent catalysts. The data indicates about 4% coke in Zone I and 10% in Zone II for runs 1,3 and 5 for spent catalyst, while for run 4 (catalyst rinsed with diesel) the coke deposition was about 10% in Zone I and about 17% in Zone II. This data suggests that diesel rinsing was not efficient. After reduction of spent catalysts at 400 °C for period of 6 h, the weight loss was similar to the fresh catalyst, indicating that most of the carbon deposited on the catalyst had been removed. This data indicates the catalyst can be efficiently regenerated with H ₂ at temperature of 400 °C.

EXAMPLE 6: Microscopic examination of catalyst

[0068] Fresh and spent catalyst were regenerated with 2% (¾ and with 100% hydrogen. Microscopic examination showed that fresh and spent catalyst reduced under hydrogen have approximately the same catalyst particle size and distribution. However, catalyst regenerated with 2% O2 agglomerated or sintered to form large particles. This data shows that for a catalyst such as Ru on a support such as T1O2, AI2O ₃ , ZSM5, S1O2, and the like, hydrogen regeneration is more effective at maintaining catalyst metal dispersion, particle size distribution, and surface area than oxygen regeneration.

[0069] To the extent that the term "includes" or "including" is used in the specification or the claims, it is intended to be inclusive in a manner similar to the term "comprising" as that term is interpreted when employed as a transitional word in a claim. Furthermore, to the extent that the term "or" is employed (e.g., A or B) it is intended to mean "A or B or both." When the applicants intend to indicate "only A or B but not both" then the term "only A or B but not both" will be employed. Thus, use of the term "or" herein is the inclusive, and not the exclusive use. See Bryan A. Garner, A Dictionary of Modern Legal Usage 624 (2d. Ed. 1995). Also, to the extent that the terms "in" or "into" are used in the specification or the claims, it is intended to additionally mean "on" or "onto." To the extent that the term "selectively" is used in the specification or the claims, it is intended to refer to a condition of a component wherein a user of the apparatus may activate or deactivate the feature or function of the component as is necessary or desired in use of the apparatus. To the extent that the terms "operatively coupled" or "operatively connected" are used in the specification or the claims, it is intended to mean that the identified components are connected in a way to perform a designated function. To the extent that the term "substantially" is used in the specification or the claims, it is intended to mean that the identified components have the relation or qualities indicated with degree of error as would be acceptable in the subject industry.

[0070] As used in the specification and the claims, the singular forms "a," "an," and "the" include the plural unless the singular is expressly specified. For example, reference to "a compound" may include a mixture of two or more compounds, as well as a single compound.

[0071] As used herein, the term "about" in conjunction with a number is intended to include ± 10% of the number. In other words, "about 10" may mean from 9 to 1 1.

[0072] As used herein, the terms "optional" and "optionally" mean that the subsequently described circumstance may or may not occur, so that the description includes instances where the circumstance occurs and instances where it does not.

[0073] As stated above, while the present application has been illustrated by the description of embodiments thereof, and while the embodiments have been described in considerable detail, it is not the intention of the applicants to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art, having the benefit of the present application. Therefore, the application, in its broader aspects, is not limited to the specific details, illustrative examples shown, or any apparatus referred to. Departures may be made from such details, examples, and apparatuses without departing from the spirit or scope of the general inventive concept.

[0074] The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope and spirit being indicated by the following claims.