PROCESS FOR SEPARATING A FINE CATALYST COMPONENT FROM A FLUID PASTE

Abstract

PROCESS FOR SEPARATING A FINE CATALYST COMPONENT AND CATALYST PRODUCT. This is a process for separating a catalyst component from a fluid paste containing catalyst by centrifugation, including separating the catalyst component from the mother liquor of the fluid paste containing catalyst using a stacked disc centrifuge equipped with an automatic discharge feature. The solids discharge from the stacked disc centrifuge is improved by adding a washing solution to the solids discharge vessel and chute of the stacked disc centrifuge.

Description

1 / 18 PROCESS FOR SEPARATING A FINE CATALYST COMPONENT FROM A FLUID PASTE FIELD

[0001] The present invention relates to a process for separating and washing a catalyst from the mother liquor using a stacked disc centrifuge equipped with an automatic discharge function. INTRODUCTION

[0002] The most commonly known type of centrifuge in the prior art and used to perform the separation of a difficult-to-filter catalyst from the mother liquor is a laboratory-scale rotating tube centrifuge. The problem with the prior art process of separating such a difficult-to-filter catalyst from the mother liquor using a laboratory-scale rotating tube centrifuge is that the capacity of a rotating tube is limited to, at most, a few liters, and the resulting separated catalyst needs to be removed manually, which further limits the processing capacity. This results in a longer separation time per gram of material. For example, in this application, the separation time per gram of material is reduced by at least a factor of two by using a laboratory-scale disc centrifuge instead of a rotating tube centrifuge.Furthermore, laboratory-scale rotating tube centrifuges are not feasible for use on a pilot-plant or commercial scale. Therefore, there is a need for a centrifugation process for separating catalyst from mother liquor where the time to separate the catalyst, particularly non-filterable or difficult-to-filter catalysts, from the mother liquor is reduced, making the process viable for pilot-plant and / or commercial scale use. Based on the catalyst particle size, especially when the catalyst is smaller than 5 microns, conventional filtration techniques such as vacuum and pressure filtration cannot be used because the flow through a filter medium is too low due to the high resistance of the deposited cake.

[0003] To date, there are very few advances in the prior art relating to catalysts and centrifuges. In an article by Laning, Steven Petition 870250057061, dated 04 / 07 / 2025, page 11 / 52 2 / 18 J., Chemical Interesterification of Palm, Palm Kernel and Coconut Oils, J. Am. Oil Chem. SOC., 1985, 62(2), 400-404, a general statement is made relating to a catalyst being neutralized with water and then passing the catalyst through a centrifugal separation operation and a drying operation.

[0004] In another article by Inoue, T., Gunjishima, I., Okamoto, A., Synthesis of Diameter-Controlled Carbon Nanotubes Using Centrifugally Classified Nanoparticle Catalysts, Carbon, 2007, 45 2164-2170, the use of a centrifuge is briefly mentioned for the synthesis of carbon nanotubes.

[0005] In the two articles above, the types of centrifuges used were not disclosed; however, a common and well-known centrifuge used at the time of the two articles above and for the type of separations described in the references above is the previously mentioned laboratory rotary tube centrifuge. For example, document CN107252740A discloses a centrifuge for processing construction coating catalyst where the centrifuge is a laboratory-scale rotary tube centrifuge. Document CN107252740A does not disclose the use of a pilot scale or an industrial (commercial) production scale centrifuge.

[0006] In an article by Fayyazi et al., Optimization of Biodiesel Production Over Chicken Egg Shell Derived CaO Catalyst in a Continuous Centrifugal Contactor Separator, Ind. Eng. Chem. Res. 2018, 57, 12742-12755, a continuous centrifugal contactor separator for a liquid-liquid reaction with a heterogeneous catalyst is mentioned. In this case, the separation objective involves separating one liquid phase from another liquid phase without any solid particles involved. Furthermore, this centrifugal contactor separator presented in the article above is a different type of equipment / technology than a centrifuge.

[0007] Document KR1241429B1 discloses a method for manufacturing an electrode catalyst for use in fuel cells wherein the method is suitable for mass production of the catalyst by applying post-catalyst manufacturing process steps including a step of Petition 870250057061, dated 04 / 07 / 2025, page 12 / 52 3 / 18 centrifugation and a washing step. The above reference does not specify the type of centrifuge used. However, on page 7, line

[0037] of document KR1241429B, there is mention of the use of a continuous centrifuge at a G-force of 3000 to 150000 and a washing step with water at 40 l / h. From the vague description of the centrifuge in document KR1241429B, one skilled in the art may assume that the centrifuge used in the above reference process refers to a tubular type centrifuge (e.g., a centrifuge used for nuclear isotope separation) which is very different from a disc centrifuge and, although the liquid discharge is continuous, the removal of solids is a manual operation.

[0008] As illustrated above, various catalysts, centrifugations, and washes have been used so far; and the most commonly used type of centrifuge is a laboratory rotating tube centrifuge. However, although stacked-disc centrifuges are commercially available for production-scale use, the prior art does not specifically focus on a catalyst centrifuge separation process or the use of stacked-disc centrifuges for catalyst separation. Therefore, it would be desirable to provide a process for catalyst separation using a stacked-disc centrifuge. SUMMARY

[0009] One embodiment of the present invention is directed to a process for separating a catalyst from mother liquor using a stacked disc centrifuge equipped with an automatic discharge function. The stacked disc centrifuge is capable of discharging isolated solids at well-defined intervals in a short period of time (e.g., 0.1 s → 10 s), thus avoiding manual catalyst recovery and centrifuge cleaning. For example, in a preferred embodiment, a stacked disc centrifuge is used to separate a catalyst present in a fluid paste (e.g., a double metal cyanide [DMC] fluid paste) by providing the necessary centrifugal force (e.g., 8000 g → 15000 g) and with an automatic discharge function. The stacked disc centrifuge is successfully used. Petition 870250057061, dated 04 / 07 / 2025, p. 13 / 52 4 / 18 on pilot scale and can be easily scaled up to production scales. The resulting centrifugal material produced from centrifugation using a stacked disc centrifuge is visibly transparent with a total suspended solids content of < 0.2% by weight. The entire quantity of fluid paste can be processed without opening the stacked disc centrifuge container, thus allowing for substantially continuous operation.

[0010] Another embodiment of the present invention is directed to a process for separating fine catalyst particles (e.g., particles < 5 µm in size) from a fluid paste using a stacked disc centrifuge and then washing the fine catalyst particles. In this embodiment, the process includes the step of injecting a small amount (e.g., < 0.5 l 1 l) of a washing liquid into the centrifuge to make the cake easier to discharge. It is well known that the remaining catalyst solids in a centrifuge after centrifugation are mixed with residual liquid and form a thick paste that is difficult to flow and discharge from the centrifuge. The process of the present invention beneficially improves the ability of the thick paste to be discharged from the centrifuge. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 is a schematic perspective view of a stacked disc centrifuge.

[0012] Figure 2 is a cross-sectional view along line 2-2 of Figure 1.

[0013] Figure 3 is a schematic flowchart of the process of the present invention. DETAILED DESCRIPTION

[0014] Fluid paste in this document means a mixture of solid catalyst particles and a solvent liquid.

[0015] Automatic solids discharge function in the present invention means a timer-controlled operation that results in the discharge of wet cake containing catalyst solids from the disc container. Petition 870250057061, dated 04 / 07 / 2025, page 14 / 52 5 / 18 stacked.

[0016] Centrifuged in the present invention means the liquid that comes out of the container of stacked discs after most of the solid particles of the catalyst have been removed.

[0017] The term wet cake, in the present invention, means a cake comprising mainly catalyst solids and some mother liquor or solvent.

[0018] Mother liquor in the present invention means the solvent mixture used in the catalyst synthesis step. This is the portion of the solution left after the precipitation of the catalyst particles.

[0019] The terms sludge removal and sludge removal(s) in the present invention mean discharging the catalyst solids cake from a stacked disc container.

[0020] As used throughout this descriptive report, unless the context clearly indicates otherwise, the abbreviations listed below have the following meanings: = means equal to; @ means in; < means less than; > means greater than; > means greater than or equal to; < means less than or equal to; g = gram(s); mg = milligram(s); kg = kilogram(s); l = liter(s); ml = milliliter(s); l / h = liter(s) per hour; ml / min = milliliter(s) per minute; MW = molecular weight, by weight; m = meter(s); m3 / h = cubic meters per hour; MN = number average molecular weight; Mw / Mn = molecular weight distribution; pm = microns; pl = microliters; mm = millimeter(s); cm = centimeter(s); min = minute(s); s = second(s); h = hour(s); °C = degree(s) Celsius; mPa.s = millipascal second; psig = pounds per square inch gauge; kPa = kilopascal; G-force = large amount of gravitational forces; % = percent; %, by volume = percent, by volume; and %, by weight = percent, by weight.

[0021] All percentages stated in the present invention are percentages by weight (%, by weight), unless otherwise indicated.

[0022] Temperatures are in degrees Celsius (°C), and ambient temperature means between 20 °C and 25 °C, unless otherwise specified. Petition 870250057061, dated 04 / 07 / 2025, page 15 / 52 6 / 18

[0023] In a broad embodiment, the present invention provides a process for extracting a catalyst component from a catalyst-containing suspension or fluid paste by separating the catalyst component (solid phase) from the mother liquor or solvent of the fluid paste (liquid phase) using a stacked disc centrifuge equipped with automatic discharge functionality. The catalyst-containing suspension or fluid paste (in the present invention, catalyst fluid paste) includes a mixture of: (a) at least one catalyst compound; (b) at least one liquid component; and (c) may contain one or more dissolved or undissolved components. For example, in one embodiment, the catalyst present in the catalyst fluid paste may be a single catalyst or a combination of two or more catalysts; and the liquid component present in the catalyst fluid paste may be one or more liquid components. In a preferred embodiment, the liquid component is an aqueous solution.Optional components can also be added to the fluid catalyst paste, if desired.

[0024] Any catalyst having a specific gravity higher than the mother liquor used in combination with the catalyst may be used in the present invention. For example, the catalyst present in the catalyst flow paste may include one or more different catalyst compounds including, for example, double metal cyanide (DMC), multi-metal cyanide, aluminum compounds and mixtures thereof. In a preferred embodiment, the catalyst compound present in the catalyst flow paste may include a DMC catalyst.

[0025] Examples of useful aluminum compounds include trialkyl aluminum compounds, such as trimethylaluminum, triethylaluminum, tributylaluminum, tribenzylaluminum and the like; aluminum alkoxides, such as aluminum trimethoxide, aluminum triethoxide, aluminum triisopropoxide, aluminum tri-t-butoxide, aluminum trisec-butoxide and the like; aluminum aryloxides, such as aluminum phenoxide and aluminum phenoxides, in which one or more of the phenoxide groups are ring-substituted by one or more of alkyl, CF3, cyano, COCH3, halogen, hydroxyl, alkoxyl and the like; aluminum oxide; Petition 870250057061, dated 04 / 07 / 2025, page 16 / 52 7 / 18 Aluminum carboxylates, such as aluminum formate, aluminum acetate, aluminum propionate, aluminum 2-ethylhexanoate, aluminum benzoate, aluminum benzoates in which one or more of the benzoate groups is ring-substituted by one or more of the following alkyl, CF3, cyano, COCH3, halogen, hydroxyl, alkoxyl and the like, aluminum salicylate, aluminum 3,5-di-t-butyl salicylate; aluminum amides, such as aluminum tris(dimethylamide), aluminum tris(diethylamide), aluminum tris(diphenylamide), aluminum tris(di(trimethylsilyl)amide and the like; aluminum acetylacetonate; aluminum t-butylacetylacetonate; and alkylaluminum oxides and alkoxides, such as diethylaluminum ethoxide, dimethylaluminum ethoxide, diethylaluminum isopropoxide, dimethylaluminum isopropoxide, methyl aluminoxane, tetraethyldialuminoxane and the like.

[0026] The amount of catalyst compound present in the catalyst flow paste of the present invention includes, for example, from 0.01% by weight to 15% by weight in one embodiment, from 0.5% by weight to 10% by weight in another embodiment, and from 1% by weight to 6% by weight in yet another embodiment. More than 15% by weight of catalyst solids may result in (1) a faster accumulation of solids in the stacked disc container than the container can discharge; and (2) a high loss of solids to the centrifuge, both of which are undesirable results.

[0027] The liquid component present in the catalyst flow paste of the present invention may include one or more liquid compounds including, for example, water, t-butanol, 2-butanol, polyether polyols and mixtures thereof. The liquid component present in the catalyst flow paste may be a single aqueous phase component, a two-phase system or a system containing an organic phase component and mixtures thereof, provided that the catalyst has a higher specific gravity than the liquid component used in the present invention.

[0028] In a preferred embodiment, the liquid compound, other than water, may include commercially available compounds, such as VORANOL™ P 4000 (a 4000 MW polyether polyol, in the present invention P 4000) Petition 870250057061, dated 04 / 07 / 2025, page 17 / 52 8 / 18 (available from The Dow Chemical Company); and mixtures of P 4000 with other liquid compounds.

[0029] The amount of liquid compound present in the fluid paste of the present invention may be, for example, from 85% by weight to 99.99% by weight in one embodiment, from 90% by weight to 99.5% by weight in another embodiment and from 94% by weight to 99% by weight in yet another embodiment.

[0030] In addition to the fluid paste components (a) and (b) above, the fluid paste may also include other optional compounds, additives, agents or components (c); and such optional compounds may be added to the fluid paste mixture in combination with either component (a) or (b) or with both components (a) and (b); or the optional component may be added as a separate addition. The optional additives or agents that may be used in the present invention may include one or more optional compounds known in the art for their use or function. For example, the optional additives, agents or components may include sec-butoxide aluminum, isopropoxide aluminum, aluminum oxide; and mixtures thereof.

[0031] The amount of optional compound used to add to the fluid paste mixture may be, for example, from 0% by weight to 5% by weight in one embodiment, from 0.01% by weight to 2% by weight in another embodiment, and from 0.5% by weight to 1.0% by weight in yet another embodiment.

[0032] In a manufacturing process to produce a catalyst, typically the resulting product is a fluid paste containing catalyst, in which undissolved solid particles are present in a liquid phase. In general, the process of the present invention includes adding other compounds, such as water, to the fluid paste containing catalyst to form an aqueous fluid paste of catalyst that can be subjected to a centrifugation process step. For example, components (a) to (c) are mixed to form the fluid paste which is then introduced into a centrifuge. For example, the ingredients that make up the fluid paste composition of catalyst can be mixed by any mixing process and equipment. Petition 870250057061, dated 04 / 07 / 2025, page 18 / 52 9 / 18 known. The order in which the ingredients are mixed is not critically important, and two or more compounds can be mixed followed by the addition of the remaining ingredients. The mixing of the components can be carried out at a temperature of 10 °C to 80 °C in one embodiment; from 15 °C to 60 °C in another embodiment; and from 20 °C to 40 °C in yet another embodiment.

[0033] As an illustration of the present invention, and not to be limited thereto, a fluid DMC catalyst paste can be prepared by mixing an aqueous solution of zinc chloride and a solution containing potassium hexacyanocobaltate (KHCC), tert-butanol (t-BuOH) and water to form a mixture in a reactor vessel. Then, a propylene oxide polyol can be added to the mixture in the reactor vessel. The process temperature in the reactor vessel can be controlled to a desired temperature, such as 30 °C. The resulting mixture formed is a fluid DMC catalyst paste.

[0034] One of the advantageous properties exhibited by the resulting fluid catalyst paste produced according to the process described above may include, for example, the fluid paste being pumpable and able to be pumped using conventional pumps without any special equipment or process conditions.

[0035] In a generic embodiment, the centrifugation process of the present invention for processing a fluid catalyst slurry and separating the catalyst from the mother liquor of the fluid slurry includes the use of a stacked disc centrifuge equipped with an automatic discharge function. The stacked disc centrifuge (also known as a disc container centrifuge) used in the present invention is described, for example, in Perry's Chemical Engineers' Handbook and can be any disc container centrifuge known in the centrifuge industry.

[0036] With reference to Figure 1, a stacked disc centrifuge is shown, usually indicated by the reference number 10. The centrifuge 10 is operationally connected to a motor, usually indicated by the reference number 40; and both pieces of equipment (centrifuge 10 and motor 40) are positioned on a base or platform, usually indicated Petition 870250057061, dated 04 / 07 / 2025, page 19 / 52 10 / 18 by reference number 50. The centrifuge 10 includes a housing 11 to house an internal rotating assembly, usually indicated by reference number 20, as shown in the cross-sectional view of Figure 2. The centrifuge 10 also includes an inlet duct 12 for introducing a fluid slurry feed 32 into the centrifuge 10; and the centrifuge 10 includes outlet ducts 13 for discharging a centrifuged stream 33 from the centrifuge 10. In addition, the centrifuge 10 includes an outlet duct 14 for discharging a sludge stream 34 from the centrifuge 10.

[0037] With reference to Figure 2, a cross-sectional view of the internal elements of the rotating assembly 20 housed within the housing 11 of the stacked disc centrifuge 10 is shown. The rotating assembly 20 includes, for example, an upper container body 21; a lower container body 22 and a plurality of disc members 23. In addition, the rotating assembly 20 includes a rotating rod or shaft 24 integral with the body 22 for rotating the centrifuge body 21, the centrifuge body 22 and the disc members 23 in the direction shown by the directional arrow 31.

[0038] Referring to Figure 2 again, an opening or inlet 25 positioned in the upper body 21 is shown, to feed a fluid paste 32 to the centrifuge 10 and the rotating assembly 20; an outlet 26 positioned in the upper body 21, to discharge a centrifugation flow 33; an outlet or port 27, positioned towards the lower body 22, to discharge a sludge flow 35 that exits the rotating assembly 20 through the port 27 and the centrifuge 10 through the conduit 14 while the centrifuge 10 is in operation.

[0039] The stacked disc centrifuge 10 is capable of applying a centrifugal force of 4000 times the G-force to 14000 times the G-force in one embodiment, 5000 times the G-force to 12000 times the G-force in another embodiment, and 6000 times the G-force to 10000 times the G-force in yet another embodiment. Based on the centrifugal force applied above in the process, the separation time can be significantly reduced. For example, the total processing time of the process, which may include, for example, Petition 870250057061, dated 04 / 07 / 2025, p. 20 / 52 11 / 18 Loading, separation, solid unloading and equipment cleaning, can be reduced by up to 50% in one mode, from 10% to 40% in another mode and from 20% to 30% in yet another mode.

[0040] The stacked disc centrifuge is ideally suited for separating particles from 0.05 µm to 100 µm in size in one general embodiment; from 0.1 µm to 50 µm in another embodiment; and from 0.5 µm to 10 µm in yet another embodiment. The stacked disc centrifuge is also ideally suited for separating particles at concentrations from 0.01% by weight to 15% by weight in one general embodiment; from 0.5% by weight to 10% by weight in another embodiment; and from 1% by weight to 6% by weight in yet another embodiment.

[0041] The capacity of the stacked disc centrifuge useful in the present invention may depend on several factors such as the size of the disc container and the ease / difficulty with which the particles can be separated. For example, as an illustration of the stacked disc centrifuge with an intermittently self-cleaning container in the present invention, and not to be limited thereto, the stacked disc centrifuge may be a Westfalia SA-1. This centrifuge, for example, has a maximum capacity of 0.001 l / ha 300 l / h in one general embodiment; 0.020 l / ha 50 l / h in another embodiment; and 0.030 l / ha 0.2 l / h in yet another embodiment. In other embodiments, different centrifuge models have different capacities.

[0042] As previously mentioned, the stacked disc centrifuge used in the present invention is equipped with an automatic solids discharge function to separate the catalyst solids from the mother liquor of a fluid paste. With reference to Figure 3, for example, a schematic flow diagram of a broad embodiment of the catalyst separation process of the present invention is shown, generally indicated by reference number 60, including the following steps:

[0043] Step (a): Provide a stacked disc centrifuge equipped with an automatic solids discharge function as indicated by number 61. Petition 870250057061, dated 04 / 07 / 2025, page 21 / 52 12 / 18

[0044] Step (b): Provide a fluid paste containing catalyst as indicated by number 62.

[0045] Step (c): Feed the stacked disc centrifuge with the fluid paste containing the catalyst as indicated by number 63.

[0046] Step (d): Centrifuge, in the stacked disc centrifuge, the fluid paste containing catalyst to form a cake and centrifuge; and remove the centrifuge in a substantially continuous manner from the stacked disc centrifuge during this centrifugation step, as indicated by number 64.

[0047] Step (e): Remove cake material from the automatically stacked disc centrifuge at a predefined interval with the help, in part, of a washing liquid, as indicated by number 65.

[0048] Step (f): Optionally, add additional flushing fluid to the discharged catalyst to complete the flushing as indicated by number 66.

[0049] A preferred embodiment of the catalyst separation process of the present invention includes the following steps:

[0050] Step (1): Provide a stacked disc centrifuge equipped with an automatic solids discharge function. This step (1) may further include setting the centrifuge operating parameters from step (1), for example, setting the feed and separation duration timer on the centrifuge control panel to a time period of 10 min to 50 min; and adjusting the container opening duration timer on the centrifuge control panel to a time period of 0.1 s to 1.0 s.

[0051] The opening and closing of the container are hydraulically actuated. For example, the operating water pressure line for the centrifuge is adjusted from 21 psig (144.8 kPa) to 36 psig (248.2 kPa).

[0052] Step (2): Provide a fluid paste containing catalyst.

[0053] Step (3): Turn on the centrifuge and allow the centrifuge to reach its maximum speed in the container. For example, as an illustration of the stacked disc centrifuge useful in the present invention, and not to be Petition 870250057061, dated 04 / 07 / 2025, p. 22 / 52 13 / 18 limited by this, the stacked disc centrifuge can be an SA-1 model. For the SA-1 model, the maximum centrifuge speed corresponds to a centrifugal force of, for example, 8000 g; and the maximum centrifuge speed is reached in a time period of, for example, 300 s. In other embodiments, different centrifuge models have different G-forces and different acceleration times.

[0054] Step (4): Feed the fluid paste into the centrifuge, for example, by adjusting a fluid paste feed pumping rate to a rate of 1.2 l / ha 12.0 l / h. After the container is full, clear centrifuge is observed coming through the centrifuge outlet line and is collected in a carboy. Total suspended solids analysis is performed on this centrifuge, and the solids content is 0.001% by weight to 0.02% by weight.

[0055] Centrifugation can be carried out at a temperature of up to 170 °C in one mode, from 10 °C to 100 °C in another mode, and from 20 °C to 50 °C in yet another mode. At centrifugation temperatures below 10 °C, the liquid may become too viscous to flow; And at centrifugation temperatures above 170 °C, the seal and the motor that rotates the centrifuge may not be able to withstand the heat, and the motor would stop operating.

[0056] The wet cake obtained after separation is converted back into a fluid paste in a washing solution containing at least water and any other liquid, such as t-BuOH, and P 4000, to remove any unwanted compounds. Generally, a typical catalyst synthesis process involves a total of three washes and four centrifugation steps. The steps to convert back into a fluid paste are carried out at temperatures of 20 °C to 40 °C and under an inert atmosphere.

[0057] Step (5): Remove sludge from catalyst solids from the centrifuge after a period of centrifugation time. For example, after 10 min of centrifugation, the centrifuge vessel is opened for 0.5 s, and during this time, the catalyst solids are removed (discharged) from the centrifuge into a receiving vessel. Sludge removal in Step (5) is carried out under an inert atmosphere at ambient temperature. Petition 870250057061, dated 04 / 07 / 2025, page 23 / 52 14 / 18

[0058] Step (6): Continuously run the pump and feed the fluid slurry into the centrifuge so that the separation is a substantially continuous operation. By substantially continuous it is meant that the vessel is open for a very short duration resulting in the discharge of the fluid slurry that is being continuously fed, but this is not a significant fraction (e.g., in this application, less than 0.3% of the total catalyst fluid slurry). In one embodiment, to remove any excess solids adhering to the vessel, vessel wall and discharge chute, the next washing solution is used to rinse the vessel and discharge chute after a predetermined number of slurry removals. For example, after 5 to 10 slurry removals.

[0059] Step (7): Collect the wet cake discharged from the centrifuge and wash it further to remove unwanted catalyst compounds. The wet cake is collected at room temperature under an inert atmosphere.

[0060] Step (8): Repeat the centrifugation and washing steps of Steps (4) to (7) a predetermined number of times, for example, 1 to 3 times, to form the final wet catalyst cake. The catalyst solids loss in each cake discharge and centrifuge is described in Table I below. The loss is measured as a percentage of total solids.

[0061] Some of the advantageous properties exhibited by the resulting catalyst solids separated according to the process described above may include, for example: (1) propoxylation actives (2) ethoxylation actives and (3) propoxylation and ethoxylation actives and any combination thereof.

[0062] The catalyst is the desired component of the present invention, and the catalyst is separated from the centrifuge after the centrifugation process. The centrifuge produced by the process of the present invention can be (1) directed to a flash distillation unit where the solvent mixture can be recovered or (2) sent to a waste handling facility. The recovered solvent can be reused in the catalyst synthesis process and / or in the washing steps of the process. Petition 870250057061, dated 04 / 07 / 2025, p. 24 / 52 15 / 18 centrifugation. For example, when the centrifuge contains t-BuOH, water, KCl, ZnCl2, charged DMC particles and mixtures thereof; if desired, the centrifuge can be distilled to remove the salts; and the resulting tBuOH and water azeotrope can be recycled back into the DMC synthesis process, and / or the azeotrope can be used to clean the centrifuge of stacked discs. Examples

[0063] The following Examples of the present invention (Ex. Inv.) and Comparative Examples (Ex. Comp.) are presented to further illustrate the present invention in detail, but should not be construed as limiting the scope of the claims. Unless otherwise indicated, all parts and percentages are expressed by weight. General procedure for centrifuging fluid catalyst paste.

[0064] A 50 l batch of double metal cyanide (DMC) catalyst flowable paste, consisting of DMC solids in a mother liquor of P 4000, t-BuOH, and water, was processed in a stacked disc centrifuge equipped with an automatic solids discharge function to separate the DMC solids from the mother liquor. The process was carried out under an inert atmosphere (N2). The wet cake obtained after separation is converted back into flowable paste, i.e., washed with a washing solution containing t-BuOH, water, and P 4000 to remove unwanted potassium in the wet cake product. The solids content loss in the resulting centrifuge is measured, and the centrifuge is discarded. The washed wet cake, the catalyst product, is then recovered. Optionally, the DMC synthesis process can be subjected to any number of washing and centrifugation steps.For example, in a preferred embodiment, the DMC synthesis procedure of the present invention includes a total of three washing steps and four centrifugation steps. Example 1

[0065] A fluid DMC slurry, described above, was subjected to a stacked disc centrifuge equipped with a discharge function. Petition 870250057061, dated 04 / 07 / 2025, p. 25 / 52 Automatic solids 16 / 18, and the DMC solids were separated from the mother liquor using the following steps:

[0066] Step (1) - The container opening timer and the separation interval timer on the centrifuge control panel of the centrifuge unit were set to 0.5 and 10 min, respectively. The opening and closing of the centrifuge container used is hydraulically actuated; the operating water pressure line was at 25 psig (172.4 kPa). The centrifuge unit was switched on and left until it reached the maximum container speed. This speed corresponded to a centrifugal force of approximately 8000 g.

[0067] Step (2) - The fluid paste feed pumping rate was set to 9.0 l / h. After the centrifuge container was full, clear centrifuge was observed coming through the outlet line and was collected in a carboy. A total suspended solids analysis was performed on this centrifuge. The solids loss in the centrifuge is described in Table I.

[0068] Step (3) - After 10 min of centrifugation, the container opened for 0.5 s, during which time the DMC solids were removed (discharged) from the centrifuge into a receiving vessel. The centrifuge container and the solids discharge chute were rinsed with 1 l of washing solution described in Example 2 to assist in removing solids stuck to the container.

[0069] Step (4) - The wet cake product resulting from Step (3) above was collected; and the loss of DMC solids in the centrifuge is described in Table I. Example 2

[0070] The wet cake collected from the Example 1 procedure was washed, converting the wet cake back into a fluid paste with the same washing solution to remove any unwanted potassium present in the DMC paste. The washing solution (26.6 kg) contained t-BuOH (49.7% by weight), water (49.7% by weight), and P 4000 (0.6% by weight). The resulting fluid DMC paste after the above washing was then centrifuged using the same stacked disc centrifuge and the same Steps (1) to Petition 870250057061, dated 04 / 07 / 2025, page 26 / 52 17 / 18 (4) of Example 1. The loss of solids from DMC in the centrifuged product in this Example 2 is described in Table I. Example 3

[0071] The wet cake collected from Example 2 was used in this Example 3; and the centrifugation and washing steps of Example 2 were repeated to obtain yet another wet DMC cake. The washing solution (17.2 kg) contained tBuOH (64.3% by weight), water (34.6% by weight), and P 4000 (1.0% by weight). The loss of solids in the centrifuge in this Example 3 is described in Table I. Example 4

[0072] The wet cake collected from Example 3 was used in this Example 4; and the centrifugation and washing steps of Example 3 were repeated to obtain yet another wet DMC cake. The washing solution (13.8 kg) contained tBuOH (98.0% by weight), water (1.4% by weight) and P 4000 (0.6% by weight). The loss of solids in the centrifuge is described in Table I. Table I - Loss of DMC catalyst in the centrifuged solution (initial catalyst quantity = 1000 q) Example No. Catalyst System lost in centrifugation (% by weight) Inv. Ex. 1 After the first fluid paste formation reaction 0.006 Inv. Ex. 2 After the 1st wash of the fluid paste 0.003 Inv. Ex. 3 After the 2nd wash of the fluid paste 0.010 Inv. Ex. 4 After 3 washes of the fluid paste 0.014

[0073] In each of the above Examples, advantageously the fluid paste was continuously fed into the centrifuge using the fluid paste feed pump to provide a separation process that was almost a continuous operation. In general, the process of the present invention has at least the following two benefits: (1) the centrifuge allows good catalyst recovery; and (2) the centrifuge allows short processing times. For example, the processing time for isolating solids from DMC using the stacked disc centrifuge compared with the rotating tube centrifuge was Petition 870250057061, dated 04 / 07 / 2025, page 27 / 52 18 / 18 reduced by up to 50%. The automatic discharge feature along with washing solids using rinsing solutions showed a reduction in the discharge time of the process from 2 hours to 10 s. Solids are lost in the centrifugation; and / or remain attached to the centrifuge vessel, discharge chute, reactor walls, and agitator blades. The entire volume of DMC fluid paste shown in Examples 1 to 4 was processed in the manner described above, and the results of the Examples above illustrate that less than 0.02% by weight of solids are lost in the centrifugation, and the total catalyst recovery is approximately 92.5%. Petition 870250057061, dated 04 / 07 / 2025, p. 28 / 52

Claims

1 / 2 CLAIMS 1. A process for separating a fine catalyst component from a catalyst-containing fluid paste by separating the catalyst component from the mother liquor of the catalyst-containing fluid paste, the process being characterized in that it comprises: (a) providing a stacked disc centrifuge equipped with an automatic discharge function; (b) providing a catalyst-containing fluid paste comprising a mixture of: (i) at least one catalyst compound; and (ii) at least one liquid component; (c) feeding the catalyst-containing fluid paste into the stacked disc centrifuge of step (a); (d) centrifuging, for a predetermined period of time, the catalyst-containing fluid paste to form a catalyst solids cake material in the centrifuge and a centrifugal material; the centrifugal material being removed substantially continuously from the centrifuge during this centrifugation step (d);and (e) remove the cake material from the centrifuge after centrifugation in step (d); wherein at least one catalyst compound is double metal cyanide.; 2. Process according to claim 1, characterized in that it further includes: (f) washing the cake material from step (e) with a washing solution substantially simultaneously during step (e) of removing the cake material from the centrifuge to remove any unwanted components from the cake material.

3. Process according to claim 1, characterized in that at least one liquid component is water.

4. Process according to claim 2, characterized in that the washing step of step (f) is carried out using water, butanol, polyether polyol or mixtures thereof as the washing solution.

5. Process, according to claim 1, characterized in that the solids content of the catalyst in the cake material is from 10 percent by weight to 40 percent by weight.

6. Process according to claim 1, characterized in that the feed rate of the fluid paste containing catalyst into the centrifuge is from 0.001 liters per hour to 300 liters per hour.

7. Process according to claim 1, characterized in that it includes additionally operating the centrifuge at a centrifugal force of 6000 g-force to 14000 g-force.

8. Process according to claim 1, characterized in that it additionally includes discharging isolated solids from the centrifuge at predetermined intervals over a period of time from 5 minutes to 60 minutes.

9. Process according to claim 1, characterized in that the resulting centrifuge produced from the centrifugation is visibly transparent with a loss of total suspended solids of 0.005 percent by weight to 0.2 percent by weight.

10. Process according to claim 1, characterized in that it additionally includes: (g) injecting a washing liquid into the centrifuge after the centrifugation step (d) and before the removal step (e). Petition 870250057061, dated 04 / 07 / 2025, p. 30 / 52

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