Method for recovering co-catalyst

Abstract

The present invention relates to a method for refining and recycling a co-catalyst from heavy fractions through incineration and crystallization processes. The method comprises the following steps: (1) mixing a stream containing a co-catalyst with at least one alcohol stream, so as to dilute the stream containing the co-catalyst and thereby reduce the viscosity thereof, the stream containing the co-catalyst being obtained from a biomass hydrogenation reaction and via evaporation and / or rectification; (2) adding the diluted stream containing the co-catalyst to an incineration apparatus for incineration, removing organic impurities and water therein by means of gasification to obtain an inorganic component, and dissolving the inorganic component in water to form an aqueous co-catalyst solution; and (3) subjecting the aqueous co-catalyst solution obtained in step (2) to evaporation, dehydration, and crystallization to obtain crystals, and optionally separating the obtained crystals so as to remove inorganic impurities, thereby obtaining the co-catalyst. The method can effectively separate organic and inorganic impurities from the co-catalyst, thereby enabling recovery of the co-catalyst with high yield and high purity, reducing operating costs, and reducing the generation of harmful substances.

Description

Methods for recovering co-catalysts Technical Field

[0001] This invention relates to a method for recovering a co-catalyst, and more particularly to a method for recovering a co-catalyst by incineration of heavy components, wherein the co-catalyst is particularly suitable for use as a co-catalyst for the hydrogenation cracking of biomass (especially soluble sugars) to prepare alcohols such as ethylene glycol. Background Technology

[0002] Molybdenum salts or tungsten salts, including sodium molybdate, ammonium metatungstate, ammonium tungstate, sodium phosphotungstate, and sodium tungstate, have high catalytic activity, strong oxidizing properties, and high resistance to toxicity, and can be used for catalytic oxidation, deoxygenation, dehydroxylation and other reactions.

[0003] These salts can be used as co-catalysts in conjunction with hydrogenation catalysts such as Ni / Ru / Rh to significantly improve the reaction efficiency of hydrogenation cracking of polyhydroxy compounds, such as C6 monosaccharides and their polysaccharides, C5 monosaccharides and their polysaccharides, soluble sugars such as sucrose and their mixtures, or various ketaldehyde acids, to produce alcohols such as ethylene glycol.

[0004] However, since the co-catalyst is usually a water-soluble homogeneous catalyst, it is typically mixed with the reactants and reacted under the action of hydrogenation catalysts such as Ni / Ru / Rh to produce an aqueous solution of alcohols such as ethylene glycol. This solution then enters the distillation system and is finally discharged from the bottom of the distillation column as a heavy component waste liquid, along with high-boiling-point organic compounds and inorganic compounds from the feedstock. Because co-catalysts are usually expensive, recovering them in high yield and purity from the heavy component waste liquid is crucial for reducing the overall process cost.

[0005] WO 2017 / 042125 reported a method of separating heavy components from distillation into two parts. The first part is directly returned to the reaction system, where the soluble tungstate can be reused. The second part, however, cannot be returned because, while enriching tungstate, the heavy components also enrich other inorganic substances from the raw materials, such as chlorides. Discharging the second part of the heavy components avoids the rapid accumulation of other inorganic contaminants in the reaction system and their poisoning of the catalyst. The second part of the heavy components, through oxidation / combustion at 300-750°C, produces a mixture of tungstate, sodium carbonate, and sodium chloride. If this mixture is reused in the reaction system along with the first part of the heavy components, it will cause a rapid accumulation of inorganic contaminants. Furthermore, directly reusing the first part only slows down the accumulation rate of inorganic contaminants; the high-boiling-point organic compounds from the reaction and distillation processes can also clog catalyst pores, leading to a decrease in catalyst activity.

[0006] US2023 / 0331648 discloses a method for recycling tungstate catalysts using incineration. This method involves burning a heavy component containing tungstate, derived from the reaction effluent and obtained through distillation, at a temperature above 900°C. The resulting tungstate-containing ash is then returned to the reaction system. Because the heavy component combustion process in this invention only separates combustible organic impurities from tungstates, impurities including chlorides, sulfates, iron compounds, heavy metal compounds from the feed, and carbonates generated during combustion accumulate in the tungstate-containing ash returned to the reaction system. These impurities shorten catalyst life and reduce the yield of the main reaction product. Furthermore, the high concentration of high-boiling-point organic compounds, including glycerol, sorbitol, and high-temperature coking compounds, as well as tungstates and other impurities, in the heavy component results in a high viscosity. The high viscosity of heavy components prevents them from being fully atomized when they enter the combustion chamber of the incinerator. This results in incomplete combustion of the organic matter in the heavy components, preventing timely gasification. The resulting coking at high temperatures leads to the formation of carbon black, which clogs the furnace and prevents effective separation from the tungstate catalyst for reuse in the reaction system, thus affecting the reaction efficiency. Furthermore, incomplete combustion also produces harmful gases such as carbon monoxide.

[0007] CN116209650 A involves directly burning a heavy component from the distillation column, consisting of a polyol containing ethylene glycol and one or more tungsten compounds. The resulting ash is then reacted with an inorganic acid at a pH below 2 to generate tungstic acid, which has low solubility in water. After filtration, the tungstic acid is washed with water to remove other water-soluble impurities. However, a total of 3.5% of tungsten is lost during the acid treatment and washing process. Furthermore, the washed tungstic acid needs to be dissolved in ethylene glycol / propylene glycol and further reacted with alkali metal hydroxides, including sodium hydroxide. After filtration to separate the insoluble matter, it is reused in the reaction system. During filtration, due to incomplete reaction, not all insoluble tungstic acid is converted into soluble tungstate, resulting in further tungsten loss and a total tungsten recovery rate of only 84.2%. Since tungsten compounds are typically very expensive, such a low yield significantly increases process costs. Moreover, the use of highly acidic organic acids in this process also greatly increases equipment investment. Additionally, excess alkali metal hydroxides are reused in the reaction system along with the tungsten-oxygen components without being separated. Although these residual alkali metal hydroxides did not significantly affect the selectivity of ethylene glycol / propylene glycol / glycerol in a reaction system with low selectivity demonstrated in this invention, alkali metal hydroxides significantly reduce the selectivity of ethylene glycol in other sugar hydrogenation techniques for producing ethylene glycol with higher ethylene glycol selectivity. Summary of the Invention

[0008] This invention provides a method for recovering a catalyst, specifically a method for refining and recycling the catalyst from heavy components through incineration and crystallization processes. This method can effectively separate organic and inorganic impurities in the catalyst, achieving high yield and high purity recovery of the catalyst, reducing operating costs, and reducing the generation of harmful substances.

[0009] Specifically, the present invention provides a method for recovering a co-catalyst, comprising the following steps:

[0010] (1) A stream containing a co-catalyst (sometimes referred to as “reinforced component” in this application) obtained from the hydrogenation reaction of biomass and by evaporation and / or distillation is mixed with at least one alcohol stream to dilute the co-catalyst-containing stream and thereby reduce its viscosity.

[0011] (2) The diluted catalyst-containing stream is added to an incineration device for incineration. Organic impurities and water are removed by gasification, and inorganic components are obtained. The inorganic components dissolve in water to form an aqueous solution of the catalyst.

[0012] (3) Evaporate and dehydrate the aqueous solution of the co-catalyst obtained in step (2) and crystallize it to obtain crystals. Optionally, separate the obtained crystals to separate the inorganic impurities, and thus obtain the co-catalyst.

[0013] If the purity of the dry-based co-catalyst in the obtained crystals is <97%, or the content of any one of chloride ions, sulfate ions, iron ions, or heavy metal ions exceeds 300 ppm, or the content of carbonate ions or aluminate ions exceeds 5% by weight, it will cause adverse effects such as reduced catalyst life and decreased reaction yield after being recycled to biomass hydrogenation reaction. Therefore, crystals with unqualified purity need to be redissolved in water and step (3) needs to be repeated until the purity of the co-catalyst is ≥97%, the content of any one of chloride ions, sulfate ions, iron ions, or heavy metal ions is ≤300 ppm, and the content of carbonate ions or aluminate ions is ≤5% by weight. Therefore, the number of crystallization times can be one or more, preferably one or two.

[0014] Here, preferred biomass refers to carbohydrate compounds, such as glucose, xylose, fructose, sucrose, arabinose, and polysaccharides. These biomasses can exist alone or in combination with each other.

[0015] In one embodiment of the present invention, the co-catalyst is selected from tungsten salts or molybdenum salts, preferably selected from one or more of ammonium tungstate, sodium phosphotungstate, sodium tungstate (e.g., sodium tungstate dihydrate), and sodium molybdate, and more preferably sodium tungstate (e.g., sodium tungstate dihydrate).

[0016] In this invention, the catalyst-containing stream mainly comprises organic components (“high-boiling substances”) and inorganic components with high boiling points (e.g., boiling points greater than 280°C at a pressure of 101 kPaA), such as glycerol, sorbitol, butanediol, catalyst, chloride ions, sulfate ions, iron ions, heavy metal ions (impurities), etc. In one embodiment of this invention, the catalyst-containing stream comprises, preferably, the following components by weight percentage:

[0017] 0-50%, preferably 1-50%, particularly preferably 1-30% glycerol, excluding the terminal 0;

[0018] 0-50%, preferably 1-50%, particularly preferably 1-30% sorbitol, excluding the terminal 0;

[0019] 0-50%, preferably 1-50%, particularly preferably 1-30% butanetetrazol, excluding the terminal 0;

[0020] 0-50%, preferably 1-50%, particularly preferably 1-30% of co-catalyst, excluding the endpoint 0;

[0021] 0-5%, preferably 0-1%, particularly preferably 0-0.1% chloride ions, excluding the terminal 0;

[0022] 0-5%, preferably 0-1%, particularly preferably 0-0.1% sulfate ions, excluding the terminal 0;

[0023] 0-5%, preferably 0-1%, particularly preferably 0-0.1% iron ions, excluding the terminal 0;

[0024] 0-5%, preferably 0-1%, particularly preferably 0-0.1% heavy metal ions, excluding the terminal 0.

[0025] In this invention, the alcohol stream mainly comprises organic components with low boiling points (e.g., boiling points not exceeding 250°C, preferably not exceeding 230°C, at a pressure of 101 kPaA), such as ethylene glycol, propylene glycol, butanediol, methanol, ethanol, isopropanol, and optionally water, etc. Preferably, the alcohol stream has a boiling point not exceeding 250°C at a pressure of 101 kPaA. For example, in one embodiment of the invention, the alcohol stream contains one or more of the following components by weight percentage, preferably containing one or more of the following alcohol components:

[0026] 0-95%, preferably 20-95%, particularly preferably 40-95% ethylene glycol, excluding the terminal 0;

[0027] 0-50%, preferably 1-50%, particularly preferably 1-35% propylene glycol, excluding the terminal 0;

[0028] 0-50%, preferably 1-50%, particularly preferably 1-45% of 1,2-butanediol, excluding the terminal 0;

[0029] 0-50%, preferably 0-40%, particularly preferably 0-30% of 2,3-butanediol, excluding the terminal 0;

[0030] 0-50%, preferably 0-40%, particularly preferably 0-30% methanol, excluding the endpoint 0;

[0031] 0-50%, preferably 0-40%, particularly preferably 0-30% ethanol, excluding the endpoint 0;

[0032] 0-50%, preferably 0-40%, particularly preferably 0-30% isopropanol, excluding the terminal 0;

[0033] 0-50%, preferably 0-40%, particularly preferably 0-30% water, excluding the endpoint 0.

[0034] In one embodiment of the present invention, the alcohol stream is preferably a stream containing alcohols obtained after evaporation and / or distillation in step (1).

[0035] For example, in one embodiment of the present invention, in step (1), the catalyst-containing stream is mixed with at least a portion of the alcohol stream obtained from evaporation and / or distillation to dilute the high-boiling-point substances and inorganic substances that cause high viscosity in the catalyst-containing stream. In one embodiment of the present invention, the diluted catalyst-containing stream contains the following components by weight percentage:

[0036] 0-20%, preferably 0-15%, particularly preferably 0-10% glycerol, excluding the terminal 0;

[0037] 0-20%, preferably 0-15%, particularly preferably 0-10% sorbitol, excluding the terminal 0;

[0038] 0-20%, preferably 0-15%, particularly preferably 0-10% of the co-catalyst, excluding the endpoint 0.

[0039] In one embodiment of the present invention, in step (1), the viscosity is reduced to below 1000 cP, preferably below 500 cP, and particularly preferably below 100 cP.

[0040] In one embodiment of the present invention, in step (1), in order to further reduce the viscosity, the diluted stream containing the co-catalyst can be heated to 40-200°C, more preferably 40-150°C, and most preferably 40-100°C.

[0041] In one embodiment of the present invention, in step (2), the incineration temperature is greater than 900°C, preferably greater than 1000°C.

[0042] In one embodiment of the present invention, in step (2), the diluted (and optionally heated) catalyst-containing stream is atomized through a nozzle and added to an incinerator or other incineration equipment for incineration, whereby the organic matter and water in the catalyst-containing stream are gasified and discharged from the top of the furnace; while the inorganic components are divided into two parts and dissolved in water, wherein the soluble part forms a catalyst aqueous solution with a mass concentration of 0-50% (excluding the endpoint 0): (i) most of the inorganic components flow out of the furnace bottom into the water in a molten state or most of the inorganic components flow out of the furnace bottom in a molten state and are then cooled and pulverized, and then added to the water; (ii) a small portion of the inorganic components are discharged from the top of the furnace with the gas and captured by a filter and then enter the water; while the catalyst aqueous solution enters a filter, and the insoluble ash is discharged from the system after filtration.

[0043] In one embodiment of the present invention, the incineration process is carried out as follows: the reaction liquid containing the co-catalyst after the reaction is evaporated and / or distilled to remove water and / or various alcohol products (which can be used as the alcohol stream of the present invention) to obtain a heavy component containing the co-catalyst; the heavy component containing the co-catalyst is diluted with at least a portion of the above-mentioned water and / or various alcohol products, the temperature is controlled at 40-200°C, preferably 40-150°C, most preferably 40-100°C, and the pressure is increased by a pump to 0.1-2.0 MPa, preferably 0.1-1.0 MPa, most preferably 0.4-0.9 MPa and atomized, and burned in an incinerator with a combustion zone greater than 900°C. The mixture of molten recovered material obtained from the bottom flow channel after incineration and fly ash intercepted by the top filter bag is directly dissolved in water. The dissolved solution rich in co-catalyst enters the evaporation crystallization system, while other organic matter is filtered and intercepted by incineration and discharged into the atmosphere as water, carbon monoxide, carbon dioxide and other gases.

[0044] In one embodiment of the invention, in step (2), the aqueous solution of the co-catalyst is filtered, for example, to remove insoluble ash.

[0045] In one embodiment of the present invention, in step (2), the inorganic component is dissolved in water to form an aqueous solution of the co-catalyst with a mass concentration of 0-50% (excluding endpoint 0).

[0046] In one embodiment of the present invention, in step (3), the operating pressure of the evaporation is ≥0.1 kPaA, preferably 0.1 kPaA-200 kPaA; and / or, in step (3), the removed water (i.e., evaporated water) can be reused in step (2) for the dissolution of inorganic components; and / or, in step (3), dehydration is stopped when the mass ratio of the co-catalyst to water is 0.1-10:1, preferably 0.5-10:1, particularly preferably 0.5-8:1; and / or, in step (3), the crystallization temperature is preferably 0-100°C, more preferably 0-80°C, even more preferably 10-80°C, and the crystallization time is preferably greater than 0.1 hours, more preferably greater than 1 hour. In one embodiment of the present invention, in step (3), the dehydrated solution is added to a crystallizer optionally equipped with a stirrer for crystallization.

[0047] In one embodiment of the invention, in step (3), the solution containing the co-catalyst crystals is added from the crystallizer to a filter or centrifuge for solid-liquid separation to obtain a filter cake and a first filtrate. The first filtrate may optionally be partially or wholly reused in the evaporation feed in step (3). Optionally, the filter cake in step (3) is washed with water or an aqueous or anhydrous organic solvent to obtain a second washing liquid. This second washing liquid may optionally be partially or wholly reused in the evaporation feed in step (3).

[0048] In step (3), multiple evaporations / crystallizations may be performed if necessary, and the number of evaporations / crystallizations is related to the product purity, so it can be adjusted according to the product purity.

[0049] The cocatalyst obtained by the cocatalyst recovery method of the present invention has good performance, and preferably contains the following impurities based on its dry weight:

[0050] Chloride ions ≤300ppm, preferably <220ppm;

[0051] Sulfate ion concentration ≤300ppm, preferably <220ppm;

[0052] Iron ions ≤300ppm, preferably <70ppm;

[0053] Heavy metal ions ≤300ppm, preferably <120ppm;

[0054] carbonate ions ≤ 5% by weight;

[0055] aluminate ions ≤ 5% by weight.

[0056] The co-catalyst recovered by the method of this invention can be mixed with water and pumped into a biomass hydrogenation reaction system for reuse in the biomass hydrogenation reaction, thereby realizing the recycling of co-catalysts throughout the entire production process. If necessary, new co-catalysts can be added to the preparation tank after purification in the crystallization system, and the amount added corresponds to the amount lost during incineration and evaporation crystallization processes.

[0057] The catalyst recovery rate of this invention is greater than 90%, preferably greater than 95%, and the purity of the recovered catalyst is greater than or equal to 97%, preferably greater than 99%. Furthermore, the method of this invention does not require the addition of additional acids or alkalis, thereby reducing operating costs and the generation of acidic and alkaline wastewater pollutants. In addition, because the viscosity-reduced materials can be fully combusted, this invention offers the following advantages: less harmful gaseous substances are generated during incineration, such as carbon monoxide and nitrogen oxides; the generation of sodium carbonate / sodium bicarbonate is reduced; and the carbon content in the bottom effluent and fly ash is significantly reduced. Therefore, the method of this invention is a more efficient method.

[0058] This invention enables the simultaneous processing of heavy components in the biomass hydrogenation process for alcohol production, utilizing an incineration + crystallization purification process to recover the co-catalyst. Specifically, by diluting the high-viscosity, high-boiling-point organic matter and inorganic matter, including the co-catalyst, in the heavy components using an alcohol stream (e.g., recycled, low-viscosity distillate fractions free of coking (e.g., monohydric and polyhydric alcohols)), the feed viscosity is reduced, ensuring atomization of the heavy components and thus guaranteeing complete combustion and gasification of organic impurities. This efficiently separates organic impurities and the co-catalyst, effectively reducing the carbon content in the bottom effluent and fly ash, and avoiding the adverse effects of organic and carbonaceous impurities when reused in the biomass hydrogenation reaction. Simultaneously, it reduces the generation of harmful gases and sodium carbonate.

[0059] Furthermore, the use of crystallization purification removes inorganic impurities from the incinerated feed containing the co-catalyst, avoiding the adverse effects of these impurities on the biomass hydrogenation reaction during reuse, and achieving a high yield recovery of the expensive co-catalyst. Simultaneously, the low-pressure or slightly negative-pressure operation of the equipment, without the introduction of acids or alkalis, significantly reduces operating costs and minimizes pollutant generation during operation. Attached Figure Description

[0060] Figure 1 is a flowchart of one embodiment of the method of the present invention, wherein the reaction liquid containing the co-catalyst discharged from the biomass hydrogenation reaction is evaporated and / or distilled to form an alcohol stream containing water and various alcohols and a stream containing the co-catalyst. The stream containing the co-catalyst is partially diluted by the alcohol stream and then incinerated to separate the organic matter and water from the inorganic matter by gasification. Then, water is added to dissolve the co-catalyst to form an aqueous solution containing the co-catalyst. The co-catalyst is then evaporated and crystallized to obtain the co-catalyst, which is then reused in the above-mentioned biomass hydrogenation reaction. Detailed Implementation

[0061] To make the technical means, creative features, achieved objectives, and effects of this invention easier to understand, embodiments are provided below to more clearly describe the technical solution of this invention. Obviously, the described embodiments are merely a part of the embodiments of this application and are intended to explain the inventive concept. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0062] Example 1

[0063] The bottom stream obtained after hydrogenating and evaporating and / or distilling biomass, containing sodium tungstate as a co-catalyst (120.9 kg / hr, co-catalyst content 10.7 wt%, chloride ion content 76 ppm, iron ion content 41 ppm, sulfate ion content 94 ppm, aluminate ion content 25 ppm, heavy metal ion content 28 ppm, sorbitol 9.5 wt%, glycerol 22.4 wt%, ethylene glycol 7.8 wt%, propylene glycol 2 wt%, 1,4-butanediol 5.6 wt%, butanetetramethylol 10.5 wt%, the remainder being other organic matter), is mixed with an alcohol stream rich in ethylene glycol (10 kg / hr, ethylene glycol content 55 wt%, propylene glycol content 10 wt%, 2,3-butanediol content 35 wt%), and the temperature is raised to 96°C. The viscosity of the mixture at this point is 90 cP. The mixture is atomized through an atomizing nozzle at a pressure of 0.4 MPaG and continuously pumped into the incinerator. Combustion is then carried out inside the furnace by adjusting the blower, primary and secondary air supply, and natural gas volume. The flue gas temperature in the combustion zone is approximately 1200°C. The effluent from the bottom of the incinerator is cooled and pulverized, and then dissolved in water along with the fly ash intercepted by the filter at the top of the incinerator to a concentration of 40% by weight, yielding a tungstate-containing solution.

[0064] The tungstate-containing solution was continuously pumped into a primary evaporator at a pressure of 8 kPaA. When the mass ratio of tungstate to water reached 3:1, the tungstate solution in the evaporator was added to a crystallizer for cooling and crystallization. The crystallization time was 10 hours, and the final crystallization temperature was 25°C. The crystallized tungstate slurry was then centrifuged to remove the mother liquor, followed by washing the filter cake with water. The total washing liquid usage was 0.6 kg / hr. The filter cake was the refined co-catalyst, with a co-catalyst yield of 95.1%. The dry basis material contained 99.75% by weight (purity) of tungstate, 128 ppm of chloride ions, 55 ppm of iron ions, 117 ppm of sulfate ions, 27 ppm of aluminate ions, 23 ppm of heavy metal ions, and 0.10% by weight of carbonate ions.

[0065] The refined co-catalyst is mixed and diluted to a concentration of 40% by weight in a co-catalyst preparation tank and then returned to the reaction system feed, thus realizing the reuse of the co-catalyst. In the biomass hydrogenation reaction using this reused co-catalyst, the catalyst lifetime can reach more than 1000 hours, which is the same as the ethylene glycol yield and catalyst lifetime in the biomass hydrogenation reaction using a new co-catalyst.

[0066] Example 2

[0067] The same catalyst-containing stream as in Example 1 was mixed with an alcohol stream rich in monohydric alcohols (60 kg / hr, 38% by weight of methanol, 50% by weight of ethanol, 4% by weight of isopropanol, and 8% by weight of water) at room temperature, resulting in a mixture viscosity of 19 cP. Other conditions were the same as in Example 1.

[0068] The purified catalyst yield was 96.5%, and the dry basis contained 99.81% by weight (purity) tungstate, 59 ppm chloride, 38 ppm iron, 55 ppm sulfate, 21 ppm aluminate, 17 ppm heavy metals, and 0.07 ppm carbonate.

[0069] The refined co-catalyst is diluted to a concentration of 40% by weight in the co-catalyst preparation tank and then returned to the reaction system feed, thus achieving co-catalyst reuse. In biomass hydrogenation reactions using this reused co-catalyst, the catalyst lifetime can reach over 1000 hours, which is the same as the ethylene glycol yield and catalyst lifetime in biomass hydrogenation reactions using new co-catalysts.

[0070] Comparative Example 1

[0071] The feed stream containing the co-catalyst, identical to that in Example 1, was not mixed with the alcohol stream and was directly fed into the incinerator operating under the same conditions. Because the feed viscosity exceeded 1000 cP, the incinerator feed nozzles could not effectively atomize the feed, resulting in incomplete combustion and gasification of the organic matter. This led to a large amount of carbonaceous material in the bottom effluent and fly ash. Consequently, the co-catalyst could not be effectively recycled for biomass hydrogenation.

[0072] Comparative Example 2

[0073] The incinerator bottom effluent and fly ash produced under the same conditions in Example 1 were not evaporated or crystallized and were directly reused as a co-catalyst in the biomass hydrogenation reaction. This reused co-catalyst contained 684 ppm chloride ions, 328 ppm iron ions, 987 ppm sulfate ions, 212 ppm aluminate ions, 266 ppm heavy metal ions, and 1.3% by weight carbonate ions. Because the chloride, iron, and sulfate ion contents exceeded 300 ppm, the catalyst life in the hydrogenation reaction was reduced to 500 hours.

[0074] Although the present invention has been described in detail above with general descriptions and specific embodiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention are within the scope of protection claimed by the present invention.

Claims

1. A method for recovering a catalyst, comprising the following steps: (1) Mixing a stream containing a co-catalyst obtained from the hydrogenation reaction of biomass and by evaporation and / or distillation with at least one alcohol stream to dilute the co-catalyst-containing stream and thereby reduce its viscosity; (2) The diluted catalyst-containing stream is added to an incineration device for incineration. Organic impurities and water are removed by gasification, and inorganic components are obtained. The inorganic components dissolve in water to form an aqueous solution of the catalyst. (3) Evaporate and dehydrate the aqueous solution of the co-catalyst obtained in step (2) and crystallize it to obtain crystals. Optionally, separate the obtained crystals to separate the inorganic impurities, and thus obtain the co-catalyst.

2. The method according to claim 1, wherein The biomass referred to here refers to carbohydrate compounds, such as glucose, xylose, fructose, sucrose, arabinose, polysaccharides, etc., which can exist alone or in combination with each other; and / or The co-catalyst is selected from tungsten salts or molybdenum salts, preferably from one or more of ammonium tungstate, sodium phosphotungstate, sodium tungstate (e.g., sodium tungstate dihydrate), and sodium molybdate, and more preferably sodium tungstate (e.g., sodium tungstate dihydrate).

3. The method according to claim 1 or 2, wherein The catalyst-containing stream mainly comprises organic components ("high-boiling substances") and inorganic components with high boiling points (e.g., boiling points above 280°C at 101 kPaA), such as glycerol, sorbitol, butanediol, catalyst, chloride ions, sulfate ions, iron ions, heavy metal ions (impurities), etc. For example, the catalyst-containing stream contains, by weight percentage, the following components, preferably: 0-50%, preferably 1-50%, particularly preferably 1-30% glycerol, excluding the terminal 0; 0-50%, preferably 1-50%, particularly preferably 1-30% sorbitol, excluding the terminal 0; 0-50%, preferably 1-50%, particularly preferably 1-30% butanetetrazol, excluding the terminal 0; 0-50%, preferably 1-50%, particularly preferably 1-30% of co-catalyst, excluding the endpoint 0; 0-5%, preferably 0-1%, particularly preferably 0-0.1% chloride ions, excluding the terminal 0; 0-5%, preferably 0-1%, particularly preferably 0-0.1% sulfate ions, excluding the terminal 0; 0-5%, preferably 0-1%, particularly preferably 0-0.1% iron ions, excluding the terminal 0; 0-5%, preferably 0-1%, particularly preferably 0-0.1% heavy metal ions, excluding the terminal 0; and / or The alcohol stream mainly comprises organic components with low boiling points (e.g., boiling points not exceeding 250°C, preferably not exceeding 230°C, at a pressure of 101 kPaA), such as ethylene glycol, propylene glycol, butanediol, methanol, ethanol, isopropanol, and optionally water, etc. Preferably, the alcohol stream has a boiling point not exceeding 250°C at a pressure of 101 kPaA. For example, the alcohol stream contains one or more of the following components by weight percentage, preferably one or more of the following alcohol components: 0-95%, preferably 20-95%, particularly preferably 40-95% ethylene glycol, excluding the terminal 0; 0-50%, preferably 1-50%, particularly preferably 1-35% propylene glycol, excluding the terminal 0; 0-50%, preferably 1-50%, particularly preferably 1-45% of 1,2-butanediol, excluding the terminal 0; 0-50%, preferably 0-40%, particularly preferably 0-30% of 2,3-butanediol, excluding the terminal 0; 0-50%, preferably 0-40%, particularly preferably 0-30% methanol, excluding the endpoint 0; 0-50%, preferably 0-40%, particularly preferably 0-30% ethanol, excluding the endpoint 0; 0-50%, preferably 0-40%, particularly preferably 0-30% isopropanol, excluding the terminal 0; 0-50%, preferably 0-40%, particularly preferably 0-30% water, excluding the endpoint 0.

4. The method according to any one of claims 1-3, wherein The alcohol stream is the alcohol-containing stream obtained after evaporation and / or distillation in step (1), and / or The diluted catalyst-containing stream contains the following components by weight percentage: 0-20%, preferably 0-15%, particularly preferably 0-10% glycerol, excluding the terminal 0; 0-20%, preferably 0-15%, particularly preferably 0-10% sorbitol, excluding the terminal 0; 0-20%, preferably 0-15%, particularly preferably 0-10% of the co-catalyst, excluding the endpoint 0.

5. The method according to any one of claims 1-4, wherein In step (1), its viscosity is reduced to below 1000 cP, preferably below 500 cP, particularly preferably below 100 cP; and / or In step (1), the diluted catalyst-containing stream is heated to 40-200°C, preferably 40-150°C, more preferably 40-100°C; and / or In step (2), the incineration temperature is greater than 900°C, preferably greater than 1000°C; and / or In step (2), the diluted (and optionally heated) catalyst-containing stream is atomized through a nozzle and added to an incinerator or other incineration equipment for combustion. The organic matter and water in the catalyst-containing stream are gasified and discharged from the top of the furnace. The inorganic components are divided into two parts and dissolved in water. The soluble part forms a catalyst aqueous solution with a mass concentration of 0-50% (excluding the endpoint 0): (i) most of the inorganic components flow out of the furnace bottom into the water in a molten state or most of the inorganic components flow out of the furnace bottom in a molten state, are cooled and crushed, and then added to the water; (ii) a small portion of the inorganic components are discharged from the top of the furnace with the gas and captured by a filter before entering the water. The catalyst aqueous solution enters a filter, and the insoluble ash is discharged from the system after filtration.

6. The method according to any one of claims 1-5, wherein The reaction liquid containing the co-catalyst after the reaction is evaporated and / or distilled to remove water and / or various alcohol products (which can be used as the alcohol stream of the present invention) to obtain a heavy component containing the co-catalyst; the heavy component containing the co-catalyst is diluted with at least a portion of the above-mentioned water and / or various alcohol products, the temperature is controlled at 40-200°C, preferably 40-150°C, most preferably 40-100°C, and the pressure is increased by a pump to 0.1-2.0 MPa, preferably 0.1-1.0 MPa, most preferably 0.4-0.9 MPa and atomized, and burned in an incinerator with a combustion zone greater than 900°C. The mixture of molten recovered material obtained from the bottom trough after incineration and fly ash intercepted by the top filter bag is directly dissolved in water. The dissolved solution rich in co-catalyst enters the evaporation crystallization system, while other organic matter is incinerated and filtered to be discharged into the atmosphere as water, carbon monoxide, carbon dioxide and other gases.

7. The method according to any one of claims 1-6, wherein In step (2), the aqueous co-catalyst solution is filtered, for example to remove insoluble ash; and / or In step (2), the inorganic component is dissolved in water to form an aqueous solution of the co-catalyst with a mass concentration of 0-50% (excluding endpoint 0); and / or In step (3), the operating pressure for evaporation is ≥0.1 kPaA, preferably 0.1 kPaA-200 kPaA; and / or In step (3), the removed water (i.e., evaporated water) is reused in step (2) for the dissolution of inorganic components; and / or In step (3), dehydration is stopped when the mass ratio of the co-catalyst to water is 0.1-10:1, preferably 0.5-10:1, more preferably 0.5-8:1; and / or In step (3), the crystallization temperature is 0-100℃, more preferably 0-80℃, even more preferably 10-80℃, and the crystallization time is greater than 0.1 hours, more preferably greater than 1 hour; and / or In step (3), the dehydrated solution is added to a crystallizer with an optional stirrer for crystallization.

8. The method according to any one of claims 1-7, wherein In step (3), the solution containing the co-catalyst crystals is added from the crystallizer to a filter or centrifuge for solid-liquid separation to obtain a filter cake and a first filtrate. The first filtrate may optionally be partially or wholly reused in the evaporation feed in step (3). Optionally, the filter cake in step (3) is washed with water or an aqueous or non-aqueous organic solvent to obtain a second washing liquid, which may optionally be partially or wholly reused in the evaporation feed in step (3).

9. The co-catalyst obtained by the recovery method according to any one of claims 1-8, wherein preferably, based on a dry weight basis, the co-catalyst contains the following impurities: Chloride ions ≤300ppm, preferably <220ppm; Sulfate ion concentration ≤300ppm, preferably <220ppm; Iron ions ≤300ppm, preferably <70ppm; Heavy metal ions ≤300ppm, preferably <120ppm; carbonate ions ≤ 5% by weight; aluminate ions ≤ 5% by weight.

10. Use of the cocatalyst obtained by any one of claims 1-8 in the hydrogenation cracking of biomass (especially soluble sugars) to produce alcohols such as ethylene glycol.

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