CROSS-REFERENCE TO RELATED APPLICATION

[0001] The application claims the benefit of the U.S. Provisional Patent Application 62/835,168 filed April 17, 2019 entitled STIRRED INJECTION MIXING PROCESS, the entirety of which is incorporated by reference herein.

BACKGROUND OF THE INVENTION

[0002] Monoethylene glycol (MEG) and monopropylene glycol (MPG) are valuable materials with a multitude of commercial applications, e.g. as heat transfer media, antifreeze, and precursors to polymers, such as PET. Ethylene and propylene glycols are typically made on an industrial scale by hydrolysis of the corresponding alkylene oxides, which are the oxidation products of ethylene and propylene, produced from fossil fuels.

[0003] In recent years, increased efforts have focused on producing chemicals, including glycols, from renewable feedstocks, such as sugar-based materials. The conversion of sugars to glycols can be seen as an efficient use of the starting materials with the oxygen atoms remaining intact in the desired product.

[0004] Current methods for the conversion of saccharides to glycols revolve around a hydrogenation/hydrogenolysis process as described in Angew. Chem. Int. Ed. 2008, 47, 8510- 8513.

[0005] A preferred methodology for a commercial scale process would be to use continuous flow technology, wherein feed is continuously provided to a reactor and product is continuously removed therefrom. By maintaining the flow of feed and the removal of product at the same levels, the reactor content remains at a more or less constant volume.

[0006] Continuous flow processes for the production of glycols from saccharide feedstock have been described in US20110313212, CN102675045, CN102643165, WO2013015955 and CN103731258. A process for the co-production of bio-fuels and glycols is described in WO2012174087.

[0007] Typical processes for the conversion of saccharides to glycols require two catalytic species in order to catalyze retro-aldol and hydrogenation reactions. Typically, the hydrogenation catalyst compositions tend to be heterogeneous. However, the retro-aldol catalysts are generally homogeneous in the reaction mixture. Such catalysts are inherently limited due to solubility constraints. Further, the saccharide-containing feedstock is generally in the form of a slurry in a solvent or as a homogeneous saccharide solution.

[0008] To ensure maximum yield, catalyst stability and limit by-product formation, feed dispersion into the reactor bulk flow should be rapid. Without proper feed dispersion, the degradation of the saccharides in zones at high concentration and high temperatures may produce side-products. Such degradation can lead to fouling and blocking of the pipes.

[0009] It is desirable to provide an improved reactor and process which provides rapid feed dispersion, particularly for the conversion of saccharides to glycols, for minimizing or eliminating the production of byproducts.

DESCRIPTION OF THE DRAWINGS

[0010] Figure la is a schematic diagram showing an aspect of an exemplary, but non limiting, embodiment of a reactor described herein.

[0011] Figure lb is a schematic diagram showing an aspect of an exemplary, but non limiting, embodiment of a reactor described herein.

[0012] Figure 2 is a schematic diagram showing a different aspect of an exemplary, but non-limiting, embodiment of the reactor described herein.

[0013] Figure 3 is a schematic diagram showing a different aspect of an exemplary, but non-limiting, embodiment of the reactor described herein.

[0014] Figure 4 is a schematic diagram showing a different aspect of an exemplary, but non-limiting, embodiment of the reactor described herein.

[0015] Figure 5 is a schematic diagram showing a different aspect of an exemplary, but non-limiting, embodiment of the reactor described herein.

[0016] Figure 6 is a schematic diagram showing a different aspect of an exemplary, but non-limiting, embodiment of the reactor described herein.

[0017] Figure 7 is a top view schematic diagram of the reactor shown in Figure 6.

[0018] Figure 8 is a schematic view of an apparatus used to perform the experiments shown in Examples 1 and 2.

SUMMARY OF THE INVENTION

[0019] The invention provides, in one embodiment, a process for the dispersion of at least one liquid feed into a liquid bulk volume of a reactor. The process includes: a) feeding the at least one liquid feed and at least one circulating reactor stream into at least one localized mixing volume located in the liquid bulk volume at a dilution factor of from 40:1 to 2000:1; b) mixing by at least one mechanical mixer the at least one liquid feed and the at least one circulating reactor stream to a degree of mixing of at least 95% in the at least one localized mixing volume within a time from 1 millisecond to 20000 milliseconds to form at least one mixed stream; and c) dispersing the at least one mixed stream into the liquid bulk volume to provide a homogeneous mixture. The dilution factor is the ratio of the at least one circulating reactor stream to the at least one liquid feed. The at least one mechanical mixer comprises a shaft having a first part located in a gas bulk volume above the liquid bulk volume and a second part located in the at least one localized mixing volume.

[0020] In another embodiment, the invention provides a reactor having a bulk volume; and at least one localized mixing volume adjacent to the bulk volume. In some embodiments, the at least one mixing volume includes a liquid inlet at a first end, a liquid outlet at a second end, at least one mechanical stirrer; and at least one liquid feed inlet. In some embodiments, the at least one mechanical stirrer has a first portion isolated from the localized mixing volume in a gas cap located in the bulk volume. In some embodiments, such as during operation, a portion of the bulk volume circulates through the at least one localized mixing volume via the liquid inlet and the liquid outlet.

DETAILED DESCRIPTION

[0021] According to some embodiments, a method for producing ethylene glycol from a carbohydrate feed may include contacting, in a reactor under hydrogenation conditions, the carbohydrate feed with a bi-functional catalyst system. The present inventors have surprisingly found that byproduct formation can be significantly decreased by rapidly dispersing the feed into the bulk volume of the reactor.

[0022] Feed dispersion may be defined as incorporating a liquid feed into a liquid bulk volume of a reactor. Reactions which require rapid feed dispersion may have liquid that is corrosive or contain magnetic particles which would make it difficult to utilize a mixer having all parts submerged in a liquid. Some reactions occur in a reactor having both a gas phase and a liquid phase such as, for example but not limited to, high pressure reactions. Some reactions/reactors will use a magnetic coupling rather than seals for practical or safety purposes. In such reactions, the mixing may occur in a continuous liquid phase.

[0023] Reactions where rapid feed dispersion would assist in reducing side product formation may also operate at conditions where both a gas volume and a liquid volume are within the reactor. In some embodiments, rapid feed dispersion may be accomplished by feeding the liquid feed and a circulating reactor stream into a localized mixing volume. The rapid feed dispersion may be accomplished via a mechanical mixing apparatus in the localized mixing volume, but the composition and/or condition of the localized mixing volume may make it preferable to have a portion of the mechanical mixing apparatus in the gas volume.

[0024] The localized mixing volume is fed from a continuous liquid phase in the reactor. The continuous liquid phase is circulated throughout the reactor and circulation may be accomplished by a variety of ways. Embodiments of a process for rapid dispersion are envisioned as being in circulating reactors, i.e., reactors having a liquid phase being circulated and having a reaction occurring in the liquid phase.

[0025] Figure la shows an embodiment of a portion 100 of a reactor 1000 which is capable of rapid feed dispersion. The reactor 1000 may be any type capable of macroflow/mixing in a reactor such as, but not limited to, a stirred tank reactor, a bubble column, an airlift loop reactor, a propeller loop reactor, or a jet loop reactor. The reactor 1000 includes a bulk volume 1050 and during operation the bulk volume may include a gas bulk volume 1100 and a liquid bulk volume 1150. In some embodiments, the portion 100 includes a portion 110 of the gas bulk volume 1100 and a portion 115 of the liquid bulk volume 1150. The liquid bulk volume 1150 is in fluid contact with a localized mixing volume 145. In some embodiments, the localized mixing volume is also in fluid contact with the portion 115 of the liquid bulk volume 1150. The localized mixing volume 145 may be defined as a liquid volume separate from the liquid bulk volume 1150 but located within the liquid bulk volume 1150. In other embodiments, the localized mixing volume 145 may be defined as liquid volume separate from the portion 115 of the liquid bulk volume 1150 but located within the portion 115 of the liquid bulk volume 1150. The localized mixing volume 145 is a discrete volume (fraction), separate of the bulk volume 1050, the liquid bulk volume 1150 or the portion 115 of the liquid bulk volume 1150. The localized mixing volume 145 is not considered in the total volume of the bulk volume 1050, the liquid bulk volume 1150 or the portion 115 of the liquid bulk volume 1150. .

[0026] A mechanical mixer 120 is also included in the reactor 1000, preferably in the portion 100 of the reactor. Due to the composition and/or conditions of the reactor during operation, the mechanical mixer has a first portion 125 located in the portion 110 of the gas bulk volume 1100 and a second portion 130 located in the localized mixing volume 145. In some embodiments, the mechanical mixer 120 may also extend through the liquid bulk volume 1150. The second portion 130 further includes an agitator 135. The first portion 125 may have parts such as, but not limited to, bearings, seals, drive, to be protected from the liquid bulk volume 1150. In some embodiments, those parts may be isolated from the bulk volume 1050 via a gas cap (not shown). In some embodiments, the mechanical mixer 120 may be magnetically coupled to the reactor. In some embodiments, the mechanical mixer 120 includes a magnetic drive having an internal magnet connected to the first portion 125. In some embodiments, the agitator 135 may include one or more propellers. As used herein, the term “propeller” also includes impellers. In some embodiments, the mechanical mixer 120 effectuates the mixing in the localized mixing volume 145 as well as, either partially or fully, the circulation of the liquid bulk volume 1150

[0027] The localized mixing volume 145 includes an inlet 150 at a first end and an outlet 155 at a second end. During operation, a circulation stream 175 will enter the localized mixing volume 145 via the inlet 150 and a mixed stream 180 will exit the localized mixing volume 145 via the outlet 155. The circulation stream 175 originates from the liquid bulk volume 1150. The reactor 1000 will be designed to circulate the liquid bulk volume 1150 through the localized mixing volume 145. The mixed stream 180 after exiting the localized mixing volume 145 will be dispersed into the liquid bulk volume 1150 to form a homogenized liquid bulk volume 1150. One skilled in the art understands there are different ways to create the general circulation from the liquid bulk volume 1150 through the localized mixing volume 145, such as, but not limited to utilizing pumps, gas lift effect, a jet loop reactor approach or even through integration with the mechanical mixer 120 (which could both supply a high shear field for fast dispersion and vertical acceleration for main circulation). In some embodiments, the circulation of the liquid bulk volume 1150 may be through an external circuit or an internal circuit to the reactor 1000. The general circulation of the liquid bulk volume 1150 provides a homogeneous mixture within the liquid bulk volume 1150.

[0028] The reactor 1000 also includes a feed inlet 160 for feeding a liquid feed to the localized mixing volume 145. In some embodiments, the feed inlet 160 may be temperature controlled. In other embodiments, the feed inlet 160 may be one or more nozzles or some other design known to one skilled in the art for supplying a liquid feed to the reactor. In some embodiments, the feed inlet 160 may be located in a side of the reactor or in the top of the reactor.

[0029] In some embodiments, the reactor 1000 may also include one or more gas inlets, one or more gas outlets, one or more liquid inlets, and one or more liquid outlets (not shown). The location of these may be either in the gas bulk volume 1100, the liquid bulk volume 1150 or a combination, depending on the application occurring in the reactor. One of ordinary skill in the art would be able to design the proper location for the proper application.

[0030] In other embodiments, the localized mixing volume 145 may be mechanically separated from the bulk volume 1050 of the reactor 100. In some embodiments, the localized mixing volume 145 may include one or more baffles or tubular separators (not shown).

[0031] The agitator 135 may be located within the localized mixing volume 145. In some embodiments, there may be more than one agitator 135 on the second portion 130 of the mechanical mixer 120 located within the localized mixing volume 145. In some embodiments, the mechanical mixer 120 may have one axis and one agitator 135. In other embodiments, the mechanical mixer 120 may have one axis and multiple agitators 135. In some embodiments, the rotational speed of the agitator 135 is at least 100 rpm, preferably over 1000 rpm. In some embodiments, there may be multiple mechanical mixers 120 in the reactor, each having its own agitator (or multiple) 135 located in the localized mixing volume 145.

[0032] In embodiments having a slurry in the reactor, the slurry should be separated to keep the solid particles in the reactor 1000 while withdrawing the liquid product substantially free of solid particles through a liquid outlet 190. The term“substantially free” herein means having a solids content of less than 1000 ppm by volume, preferably less than 100 ppm by volume, most preferably less than 20 ppm by volume. The solid particles may be maintained in the reactor 1000 such that downstream processes are not affected. In some embodiments, the separation of the slurry into a liquid substantially free of solid particles (i.e., liquid product exiting the liquid outlet 190) and a liquid enriched in solid particles may occur internal to the reactor or may occur external to the reactor. In both scenarios, the liquid enriched in solid particles should be maintained in or returned to the reactor 1000.

[0033] As shown in Figure la, a separator 185 may be internal to the reactor 1000. Numerous methods to accomplish the separation of the slurry in the reactor may be used, for example, but not limited to, a filter, a settler, a cyclone, a centrifuge or magnetism (depending on the slurry composition). The separator 185 may be used within the reactor 1000 having a stream from the liquid bulk volume 1150 traversing the separator producing a stream with the liquid enriched in solid particles being returned to the reactor 1000 and the liquid product substantially free of solid particles exiting the reactor 1000 via the liquid outlet 190. In some embodiments, a microfilter with pore size smaller than the particle size may be used within the liquid bulk volume 1150, preferably a crossflow microfilter. The crossflow allows for the liquid to sweep away particles from the filter and avoid the filter plugging up. [0034] The separator 185 may be integrated in the bulk liquid volume 1150, preferably in a high cross-sectional area section. In some embodiments, the solid particles may be magnetic and they may be retrieved by applying and releasing a magnetic field. In those embodiments, one of ordinary skill in the art could design a series of valves/switching ports to switch the outlet stream of the separator 185 to either the liquid outlet 190 or back to the reactor 1000.

[0035] As shown in Figure lb, the separator 185 may be located external to the reactor 1000. In some embodiments, prior to entering the separator 185, a slurry stream 140 from the liquid bulk volume 1150 may be fed to a finishing reactor 195. The finishing reactor 195 provides the benefit of the reaction nearing 100% conversion. The finishing reactor 195 may be optional. After the finishing reactor 195, the slurry stream enters the separator 185 producing a stream 165 with the liquid enriched in solid particles being returned to the reactor 200 and the liquid product substantially free of solid particles exiting the reactor 1000 via the liquid outlet 190. Other design factors, such as the shape of the bottom of the reactor, the location of the inlets/outlets may be designed for purpose by one of ordinary skill in the art.

[0036] In other embodiments, the reactor 1000 may include multiple portions 100 of the reactor, each portion having a localized mixing volume 145. Each portion’s localized mixing volume 145 includes an agitator 135. In some embodiments, adjacent localized mixing volumes 145 may have agitators 135 rotating in the same direction (either clockwise or counterclockwise). In other embodiments, adjacent localized mixing volumes 145 may have agitators 135 rotating in the opposite direction (either clockwise or counterclockwise). In some embodiments, each portion 100 includes the same components as discussed above.

[0037] Figure 2 shows an embodiment of a reactor 200 wherein a process for the dispersion of at least one liquid feed into a liquid bulk volume of a reactor will be described. Reference numbers remain the same throughout the figures for items identical or similar to those other figures and will not be described further herein. A reactor 200 comprises a downcomer 205 and a riser 210. In some embodiments, there may be more than one downcomer 205 and more than one riser 210. The downcomer 205 and the riser 210 are fluidly coupled. In other embodiments, there may be more than one downcomer 205 being fluidly coupled to the riser 210. The portion 100 of the reactor described in Figure 1 may be located in the downcomer 205. The gas bulk volume 1110 is the portion 110. The liquid bulk volume 1150 is the sum of the portion 115 located in the downcomer 205, the remainder of the liquid bulk volume in the downcomer 205 and the liquid bulk volume located in the riser 210. [0038] In some embodiments, the mechanical mixer 120 further includes a first agitator 135a and a second agitator 135b, both located in the localized mixing volume 145. In some embodiments, the agitator 135 may include one or more axis and one or more propellers. As used herein, the term“propeller” also includes impellers.

[0039] In some embodiments, the first portion 125 may include a coupling 215 having a first portion 215a located in the portion 110 of the gas bulk volume 1100 and a second portion 215b located outside the reactor 200.

[0040] In some embodiments, the coupling 215 is a magnetic coupling. The coupling 215 may include parts, such as, but not limited to, bearings, seals, drive, which will be protected from the liquid bulk volume 1150. In some embodiments, those parts may be isolated in the gas bulk volume 1100 via a gas cap (not shown). In some embodiments, the mechanical mixer 120 may be magnetically coupled to the reactor.

[0041] In some embodiments, a pump 220 is used to circulate the liquid bulk volume 1150 from the riser 210 to the downcomer 205 and through the localized mixing volume 145. In other embodiments, other methods to circulate the liquid bulk volume 1150 through the reactor 200 may be designed by one of skill in the art. The liquid bulk volume 1150 may include a catalyst system. The catalyst system may be homogeneous, heterogeneous or a combination of both. In some embodiments, the catalyst system may include magnetic particles.

[0042] The circulation stream 175 and a liquid feed 260 via feed inlet 160 are fed to the localized mixing volume 145. The localized mixing volume 145 is less than 30vol% of the liquid bulk volume 1150. The circulation stream 175 is a portion of the liquid bulk volume 1150. The ratio of the circulation stream 175 to the liquid feed 260 may be defined as a dilution factor and should be in the range of from 40:1 to 2000: 1. In other embodiments, the dilution factor should range from 100:1 to 1000: 1 or from 200:1 to 600:1. The circulation stream 175 and the liquid feed 260 are mixed to a degree of mixing of at least 95%, preferably at least 99%, more preferably at least 99.5% within a time ranging from about 1 millisecond to about 20000 milliseconds to produce the mixed stream 180. In other embodiments circulation stream 175 and the liquid feed 260 should be mixed to a degree of mixing of at least 95%, preferably at least 99%, more preferably at least 99.5%in the localized mixing volume within a time from 1 millisecond to 6000 milliseconds or from 1 millisecond to 2000 milliseconds.

[0043] The degree of mixing is defined by Danckwerts [Danckwerts P.V., The definition and measurement of some characteristics of mixtures, Appl. Sci. Res., Sect A 3 (1952), p. 279- 296] as 100% minus the degree of separation where the degree of separation is defined by as

where S is the degree of separation,

s the standard deviation of the density distribution function of the concentration of the liquid feed components within the mixed stream 180 and

Go the standard deviation of the density distribution function of the concentration of the liquid feed components in a hypothetical stream consisting of the liquid feed 260 and the circulating reactor stream 175 where no mixing has taken place.

[0044] The mixing may be performed by the first agitator 135a and the second agitator 135b. The mixed stream 230 is dispersed into the downcomer 205 to be distributed in the liquid bulk volume 1150 to form a homogeneous mixture.

[0045] In some embodiments, one or more baffles 265 may be located in the localized mixing volume 145. In other embodiments, other mechanical means may be utilized to enhance the dispersion of the liquid feed 260 in the localized mixing volume 145.

[0046] In some embodiments, the reactor 200 includes a gas inlet 270 and a gas outlet 280 in the portion 110 of the gas bulk volume 1100. The gas inlet 270 may be used to inject a gas for a reaction occurring in the reactor 200 and the gas outlet 280 may be for purging excess gas. In other embodiments, an injection of gas into the liquid bulk volume 1150 may effectuate mass transfer from the gas phase into the liquid bulk volume 1150 as well as circulating the circulation stream 175 through the localized mixing volume 145.

[0047] After being dispersed into the downcomer 205, the mixed stream 180 and the liquid contents of the downcomer are pumped back into the riser 210 and a liquid product is taken out of the reactor via a liquid outlet 290.

[0048] In some embodiments, the reactor 200 may be used for a glycols process having the liquid feed 260 as a saccharide-containing feedstock. Examples of the saccharide-containing feedstock may include or be derived from at least one saccharide selected from the group consisting of monosaccharides, disaccharides, oligosaccharides and polysaccharides. Saccharides, also referred to as sugars, carbohydrates or organic oxygenates, comprise monomeric, dimeric, oligomeric and polymeric aldoses, ketoses, or combinations of aldoses and ketoses, the monomeric form comprising at least one alcohol and a carbonyl function, being described by the general formula of C _n tk _n O _n (n = 4, 5 or 6). Typical C4 monosaccharides comprise erythrose and threose, typical C5 saccharide monomers include xylose and arabinose and typical Ce sugars comprise aldoses like glucose, mannose and galactose, while a common G ketose is fructose. Examples of dimeric saccharides, comprising similar or different monomeric saccharides, include sucrose, maltose and cellobiose. Saccharide oligomers are present in corn syrup. Polymeric saccharides include cellulose, starch, glycogen, hemicellulose, chitin, and mixtures thereof.

[0049] If the saccharide-containing feedstock used includes or is derived from oligosaccharides or polysaccharides, the saccharide-containing feedstock may, in some embodiments, be subjected to pre-treatment before being used in the process of the present invention. Suitable pre-treatment methods are known in the art and one or more may be selected from the group including, but not limited to, sizing, drying, grinding, hot water treatment, steam treatment, hydrolysis, pyrolysis, thermal treatment, chemical treatment, biological treatment. However, after said pre-treatment, the saccharide feed still comprises mainly monomeric and/or oligomeric saccharides. Said saccharides are, preferably, soluble in the reaction solvent.

[0050] Preferably, the saccharide feed, after any pre-treatment, comprises saccharides selected from glucose, starch and/or hydrolyzed starch. Hydrolyzed starch comprises glucose, sucrose, maltose and oligomeric forms of glucose. Said saccharides are suitably present as a solution, a suspension or a slurry in a first solvent.

[0051] The first solvent may be water or a Ci to G alcohol or polyalcohol (including sugar alcohols), ethers, and other suitable organic compounds or mixtures thereof. Preferred Ci to G, alcohols include methanol, ethanol, 1 -propanol and iso-propanol. Polyalcohols of use include glycols, particularly products of the hydrogenation/ retro-aldol reaction, glycerol, erythritol, threitol, sorbitol and mixtures thereof. Preferably, the first solvent comprises water.

[0052] In some embodiments, the liquid feed 260 may include at least lwt% saccharide in a solvent. Preferably the liquid feed 260 comprises at least 2wt%, more preferably at least 5wt%, even more preferably at least 10wt%, most preferably at least 20wt% saccharide in the solvent. Suitably, the liquid feed 260 contains no more than 50wt%, preferably no more than 40wt% saccharide in the solvent. The solvent may be fed to the reactor together with the saccharide-containing feedstock, either through the same feed pipe or at a separate point in the reactor.

[0053] It is envisaged that the composition and amount of the liquid feed 260 and the contents of the liquid bulk volume 1150 will be coordinated such that the concentration of saccharide in the solvent in the reactor 200 while the reaction is proceeding is at least 0.01wt% saccharide in solvent. Preferably the concentration of saccharide in solvent in the reactor is at least 0.02wt%. Most preferably the concentration of saccharide in solvent in the reactor is at least 0.25 wt%. It is envisaged that the composition and amount of the liquid feed 260 and the contents of the liquid bulk volume 1150 will be coordinated such that the concentration of saccharide in the solvent in the reactor while the reaction is proceeding is at most 5wt% saccharide in solvent. Preferably the concentration of saccharide in solvent in the reactor is at most 2wt%. Most preferably the concentration of saccharide in solvent in the reactor is at most 0.5wt%

[0054] The liquid feed 260 may be contacted with a bi-functional catalyst system in the localized mixing volume 145. The bi-functional catalyst system is throughout the bulk liquid volume 1150. The bi-functional catalyst system may include a heterogeneous hydrogenation catalyst and a soluble retro-aldol catalyst. In some embodiments, the soluble retro-aldol catalyst may be fed along with the liquid feed 260 or may be fed separately to the reactor. In some embodiments, the reactor is filled with the heterogeneous hydrogenation catalytic composition. The volume percent of the hydrogenation catalyst composition (based on the amount of metal in said composition) to the saccharide feed is suitably in the range of from 0.01 to 10 vol%. Said hydrogenation catalyst composition is preferably heterogeneous and is retained or supported within the reactor vessel. Further, said hydrogenation catalytic composition also preferably includes one or more materials selected from transition metals from groups 8, 9 or 10 or compounds thereof, with catalytic hydrogenation capabilities.

[0055] More preferably, the hydrogenation catalytic composition comprises one or more metals selected from the list consisting of iron, cobalt, nickel, ruthenium, rhodium, palladium, iridium and platinum. This metal or metals may be present in elemental form or as compounds. It is also suitable that this component is present in chemical combination with one or more other ingredients in the hydrogenation catalytic composition. It is required that the hydrogenation catalytic composition has catalytic hydrogenation capabilities and it is capable of catalyzing the hydrogenation of material present in the reactor.

[0056] In one embodiment, the hydrogenation catalytic composition comprises metals supported on a solid support. In this embodiment, the solid supports may be in the form of a powder or in the form of regular or irregular shapes such as spheres, extrudates, pills, pellets, tablets, monolithic structures. Alternatively, the solid supports may be present as surface coatings, for examples on the surfaces of tubes or heat exchangers. Suitable solid support materials are those known to the skilled person and include, but are not limited to aluminas, silicas, zirconium oxide, magnesium oxide, zinc oxide, titanium oxide, carbon, activated carbon, zeolites, clays, silica alumina and mixtures thereof. [0057] Alternatively, the heterogeneous hydrogenation catalytic composition may be present as Raney material, such as Raney nickel, present in a powder form.

[0058] The soluble retro-aldol catalyst composition comprises one or more compound, complex or elemental material comprising tungsten, molybdenum, vanadium, niobium, chromium, titanium or zirconium. In some embodiments, the retro-aldol catalyst composition comprises one or more material selected from the list consisting of tungstic acid, molybdic acid, ammonium tungstate, ammonium metatungstate, ammonium paratungstate, tungstate compounds comprising at least one Group I or II element, metatungstate compounds comprising at least one Group I or II element, paratungstate compounds comprising at least one Group I or II element, heteropoly compounds of tungsten, heteropoly compounds of molybdenum, tungsten oxides, molybdenum oxides, vanadium oxides, metavanadates, chromium oxides, chromium sulfate, titanium ethoxide, zirconium acetate, zirconium carbonate, zirconium hydroxide, niobium oxides, niobium ethoxide, and combinations thereof. The metal component is in a form other than a carbide, nitride, or phosphide. Preferably, the retro-aldol catalyst composition comprises one or more compound, complex or elemental material selected from those containing tungsten or molybdenum.

[0059] In some embodiments, the retro-aldol catalyst is a tungsten-based retro-aldol catalytic species and an alkali metal containing species in a second solvent, making up a retro- aldol stream.

[0060] The second solvent is preferably selected from Ci to Ce alcohols or poly alcohols (including sugar alcohols), ethers, and other suitable organic compounds or mixtures thereof. Polyalcohols of use include glycols, particularly products of the hydrogenation/ retro-aldol reaction, glycerol, erythritol, threitol, sorbitol and mixtures thereof.

[0061] The alkali metal in the alkali metal containing species is preferably lithium, sodium or potassium, more preferably sodium. Further, the alkali metal containing species is preferably present as or derived from a buffer, and/or any other component used to control or modify pH, and/or the tungsten-based retro-aldol catalytic species present in the reactor system.

[0062] The weight ratio of the metal-based retro-aldol catalytic species (based on the amount of metal in said composition) to sugar in the combined feed stream is suitably in the range of from 1:1 to 1:1000. In some embodiments, the combined feed is the retro-aldol catalytic species and the liquid feed, which may be fed together through a single inlet or separately through multiple inlets. [0063] The molar ratio of alkali metakmetal in the combined feed stream is maintained in the range of from 0.55 to 6.0. Preferably, the molar ratio of alkali metakmetal in the combined feed stream is maintained in the range of from 0.55 to 3.0, more preferably in the range of from 2.0 to 3.0.

[0064] For a glycols process, the liquid feed 260 may include the homogeneous catalyst and the saccharide containing feed. The liquid feed 260 should be maintained at a temperature lower than the degradation temperature of the saccharide-containing feedstock. As used herein, the term degradation temperature relates to the temperature at which 1% of the saccharide present is degraded within an hour and will vary depending on the saccharides present. The temperature of the saccharide-containing feedstock in the feed pipe is suitably maintained at least 10°C, more preferably at least 20°C, even more preferably at least 50°C, below the degradation temperature of the saccharide contained therein.

[0065] The reactor 200 is at a temperature between 130 and 300 °C, preferably between 160 and 250 °C. The temperature in the reactor is suitably at least 130°C, preferably at least 150°C, more preferably at least 170 °C, most preferably at least 190°C. The temperature in the reactor is suitably at most 300°C, preferably at most 280°C, more preferably at most 270°C, even more preferably at most 250°C. Preferably, the temperature in the reactor is above the degradation temperature of the one or more saccharides in the saccharide feedstock. Preferably, the reactor is heated to a temperature within these limits before addition of any fresh saccharide feed and is maintained at such a temperature until all reaction is complete.

[0066] The reactor 200 is at a pressure ranging from 1 to 20000 kPa, preferably between 1000 and 15000 kPa, most preferably between 4000 and 12000 kPa. The liquid residence time of the liquid bulk volume ranges from 15 and 600 minutes. The dilution factor ranges from 40:1 to 2000:1, preferably from 100:1 to 1000:1, more preferably from 200:1 to 600:1.

[0067] Hydrogen is also present in the reactor with the retro-aldol catalytic composition. The hydrogen may enter via the gas inlet 270 and excess hydrogen may exit the reactor 200 via the gas outlet 280.

[0068] While an embodiment of a reactor has been described for dispersing a liquid feed rapidly into a bulk circulating volume, it is envisioned that many other reactor embodiments would be appropriate for generating the circulation in the reactor for the homogenization of the reaction. For example, while a pump has been shown for circulating the liquid bulk volume 1150, a gas lift apparatus or even the mechanical mixer itself may be designed to circulate the liquid bulk volume through the localized mixing volume 145. Mass transfer, if a part of the reaction of the reactor, may be affected by a bubble column, an ejector (either gas or liquid driven), a gas lift or integrated in the mechanical mixer. The localized mixing volume 145 may be integrated in the main reactor or may be located in an external circuit. While a single downcomer has been shown with a matching riser, there may be multiple downcomers associated with a single riser. These various configurations are not exhaustive and one of ordinary skill in the art would be able to design a reactor configuration that would provide homogenization within the reactor.

[0069] Figure 3 shows an embodiment of a reactor 300 wherein a process for the dispersion of at least one liquid feed into a liquid bulk volume of a reactor will be described. Reference numbers remain the same throughout the figures for items identical or similar to those other figures and will not be described further herein. Reactor 300 includes a downcomer 205 and an riser 210. The downcomer 205 and the riser 210 are fluidly coupled. The portion 100 of the reactor described in Figure 1 may be located in the downcomer 205. The gas bulk volume 1110 is the portion 110 in the downcomer and a portion 310 of the gas bulk volume located in the riser 210. The liquid bulk volume 1150 is the sum of the portion 115 located in the downcomer 205, the remainder of the liquid bulk volume in the downcomer 205 and the portion of the liquid bulk volume located in the riser 210.

[0070] In some embodiments, the reactor 300 includes a gas inlet 370 and a gas outlet 380 located in the riser 210. The gas inlet 370 may be located in the bottom of the riser 210 and may also be fluidly coupled to the pump 220 via the pump outlet. The gas inlet 370 may be used to inject a gas for a reaction occurring in the reactor 300 and the gas outlet 380 may be for purging excess gas or for sending to a recycle compressor.

[0071] A weir 360 may be located in the riser 210 for directing the circulation stream 175 into the downcomer. A liquid product may be drawn from a liquid outlet 390 located in the portion 115 of the liquid bulk volume in the downcomer 205.

[0072] One skilled in the art would be able to design alternate locations of the gas inlet 370, the gas outlet 380 and the liquid outlet 390.

[0073] Figure 4 shows an embodiment of a reactor 400 wherein a process for the dispersion of at least one liquid feed into a liquid bulk volume of a reactor will be described. Reactor 400 includes a first downcomer 205 a, a second downcomer 205b and an riser 210. The first downcomer 205a, the second downcomer 205b and the riser 210 are fluidly coupled. A first portion 100a of the reactor may be located in the first downcomer 205 a and a second portion 100b of the reactor described may be located in the second downcomer 205b. [0074] The reactor 400 includes a first localized mixing volumes 145a and a second localized mixing volume 145b. Each localized mixing volume 145a and 145b include the same components as previously described, just noting either an“a” or“b” reference to distinguish which localized mixing volume they reside in. In embodiments having more than one localized mixing volume, the sum of the localized mixing volumes 145a and 145b is less than 30vol% of the liquid bulk volume 1150. While only two localized mixing volumes are shown, there may be multiple other localized mixing volumes which surround the riser 210 wherein the sum of the localized mixing volumes is less than 30vol% of the liquid bulk volume 1150.

[0075] The first portion 100a and the second portion 100b are as described as above for the portion 100. The gas bulk volume 1110 is the portion 110a in the first downcomer 205a, the portion 110b in the second downcomer 205b and the portion 310 of the gas bulk volume located in the riser 210. The liquid bulk volume 1150 is the sum of the first portion 115a located in the first downcomer 205a, the second portion 115b located in the second downcomer 205b, the remainder of the liquid bulk volume in the first downcomer 205a, the remainder of the liquid bulk volume in the second downcomer 205b and the portion of the liquid bulk volume located in the riser 210.

[0076] In some embodiments, the reactor 400 includes a gas inlet 470 and a gas outlet 480 located in the riser 210. The gas inlet 470 may be located in the bottom of the riser 210, wherein the bottom of the reactor 400 is tapered. The gas inlet 470 may be used to inject a gas for a reaction occurring in the reactor 400 and to circulate the liquid bulk volume 1150 from the riser 210 to the first downcomer 205a and the second downcomer 205b, through the liquid mixing zones 145a and 145b. The gas outlet 480 may be located in the gas bulk volume 310 of the riser 210 for purging excess gas or for sending to a recycle compressor.

[0077] Weirs 360a and 360b may be located in the riser 210 for directing the circulation streams 175a and 175b into the first downcomer 205a and the second downcomer 205b, respectively. A liquid product may be drawn from a liquid outlet 490 located in the portion 115b of the liquid bulk volume in the second downcomer 205b. One skilled in the art would be able to design alternate locations of the gas inlet 470, the gas outlet 480 and the liquid outlet 490.

[0078] Figure 5 shows an embodiment of a reactor 500 wherein a process for the dispersion of at least one liquid feed into a liquid bulk volume of a reactor will be described. Reactor 500 includes a first downcomer 205 a, a second downcomer 205b and an riser 210. The first downcomer 205a, the second downcomer 205b and the riser 210 are fluidly coupled. A first portion 100a of the reactor may be located in the first downcomer 205 a and a second portion 100b of the reactor described may be located in the second downcomer 205b.

[0079] The reactor 500 includes a first localized mixing volumes 145a and a second localized mixing volume 145b. Each localized mixing volume 145a and 145b include the same components as previously described, just noting either an“a” or“b” reference to distinguish which localized mixing volume they reside in. In embodiments having more than one localized mixing volume, the sum of the localized mixing volumes 145a and 145b is less than 30vol% of the liquid bulk volume 1150. While only two localized mixing volumes are shown, there may be multiple other localized mixing volumes which surround the riser 210 wherein the sum of the localized mixing volumes is less than 30vol% of the liquid bulk volume 1150.

[0080] The first portion 100a and the second portion 100b are as described as above for the portion 100. The gas bulk volume 1110 is the portion 110a in the first downcomer 205a, the portion 110b in the second downcomer 205b and the portion 310 of the gas bulk volume located in the riser 210. The liquid bulk volume 1150 is the sum of the first portion 115a located in the first downcomer 205a, the second portion 115b located in the second downcomer 205b, the remainder of the liquid bulk volume in the first downcomer 205a, the remainder of the liquid bulk volume in the second downcomer 205b and the portion of the liquid bulk volume located in the riser 210.

[0081] In some embodiments, the bottoms of the first localized mixing volumes 145a and the second localized mixing volume 145b are tapered. In some embodiments, the mechanical mixer 120 includes the first agitator 135a, the second agitator 135b and a third agitator 135c. In some embodiments, the first agitator 135a, the second agitator 135b and the third agitator 135c may be the same or may each have a different configuration.

[0082] In some embodiments, the reactor 500 includes a gas inlet 570 and a gas outlet 580 located in the riser 210. The gas inlet 570 may be located in the bottom of the riser 210, wherein the gas inlet 570 may include a sparger. The gas inlet 570 may be used to inject a gas for a reaction occurring in the reactor 500 and to circulate the liquid bulk volume 1150 from the riser 210 to the first downcomer 205a and the second downcomer 205b, through the liquid mixing zones 145a and 145b. The gas outlet 580 may be located in the gas bulk volume 1100 of the reactor 500 for purging excess gas or for sending to a recycle compressor.

[0083] Weirs 360a and 360b may be located in the riser 210 for directing the circulation streams 175a and 175b into the first downcomer 205a and the second downcomer 205b, respectively. A liquid product may be drawn from a liquid outlet 590 located in the portion 115b of the liquid bulk volume in the second downcomer 205b. One skilled in the art would be able to design alternate locations of the gas inlet 470, the gas outlet 480 and the liquid outlet 490.

[0084] Figures 6 and 7 show an embodiment of a reactor 600 wherein a process for the dispersion of at least one liquid feed into a liquid bulk volume of a reactor will be described having multiple downcomers. Figure 6 shows a cross section, taken along the line in Figure 7, of. Figure 7 shows a cross section of reactor 600 taken along the line in Figure 6, showing twelve downcomers 205a through 2051 fluidly coupled to an riser 210a. The twelve downcomers 205 a through 2051 and the riser 210 are fluidly coupled via corresponding pumps 620a through 6201. Each of the twelve downcomers 205a through 2051 include an individual portion 100 as described in Figure 1.

[0085] The reactor 600 includes twelve localized mixing volumes 145a through 1451 (not all are shown in the Figures). Each localized mixing volume 145a through 1451 include the same components as previously described, just noting either an alphabetic reference to distinguish which localized mixing volume they reside in. In embodiments having more than one localized mixing volume, the sum of the localized mixing volumes 145a through 1451 is less than 30vol% of the liquid bulk volume 1150.

[0086] The gas bulk volume 1110 is the portion 110a through 1101 in the twelve downcomers 205a through 2051 and the portion 310 of the gas bulk volume located in the riser 210. The liquid bulk volume 1150 is the sum of the portion 115a through 1151 located in the twelve downcomers 205 a through 2051, the remainder of the liquid bulk volume in the twelve downcomers 205a through 2051, and the portion of the liquid bulk volume located in the riser 210.

[0087] In some embodiments, the reactor 600 includes a gas inlet 670 and a gas outlet 680 located in the riser 210. The gas inlet 670 may be located in the bottom of the riser 210, wherein the bottom of the reactor 400 is tapered and may be fluidly coupled to pumps 220a through 2201. The gas inlet 670 may be used to inject a gas for a reaction occurring in the reactor 300 and to circulate the liquid bulk volume 1150 along with the pumps 220a through 2201 from the riser 210 to the twelve downcomers 205a through 2051, through the liquid mixing zones 145a through 1451. The gas outlet 480 may be located in the gas bulk volume 310 of the riser 210 for purging excess gas or for sending to a recycle compressor.

[0088] A weir 360 may be located in the riser 210 for directing the circulation streams 175a through 1751 into the twelve downcomers 205a through 2051, respectively. The weir 360 may prevent bubbles out of the twelve downcomers 205a through 2051 and thus the pumps220a through 2201. In other embodiments, individual downcomers may not have individual pumps, but pumps may be designed to have an inlet being fed from multiple downcomers and providing a fluid stream to the riser 210.

[0089] A liquid product may be drawn from a liquid outlet 690 located in the liquid bulk volume in the riser 210. One skilled in the art would be able to design alternate locations of the gas inlet 470, the gas outlet 480 and the liquid outlet 490.

[0090] While not specifically shown in the embodiments of Figures 2-7, one skilled in the art will be able to design a separator 185 as described in either Figures la and lb to be used either internally or externally to the reactors shown in Figures 2-7 to produce a liquid product substantially free of solid particles through the variously described liquid outlets while maintaining or returning the solid particles in the reactor 1000.

EXAMPLES

Experimental Apparatus:

[0091] The apparatus used to perform the experiments shown in Example 1 is schematically represented in Figure 8. A one-liter Hastelloy-C autoclave, Reactor 100 including a stirrer 110, was equipped with automatic controls for the control of reactor temperature, back-pressure, liquid level, and stirrer speed. The feed line-1 was equipped with a gas flow meter and was used to provide a continuous flow of hydrogen gas into the reactor. Each of the liquid feed lines 2 and 3, was equipped with a pump and a mass flow meter. Line 2 was used to continuously feed a solution containing the sodium tungstate retro-Aldol catalyst, and the glycolic acid pH control agent. Line 3 was used to supply the glucose feed either as a continuous flow or as an intermittent flow. Filter element 5 was used to retain the heterogeneous hydrogenation catalyst inside the reactor while allowing the flow of the liquid product, which was controlled by valve-10, via line 7. The excess gas pressure present in the reactor was vented via line 6 by the use of the back-pressure control valve- 12.

[0092] Line-7 was equipped with an in-line product cooler with the ability to cool down the product mixture to or below room temperature. The product effluent passing through line- 7 was set up to flow into a gas-liquid separator 200. Valve-11 was used to control the level in the gas-liquid separator. Samples of the product stream were taken via line-13 for analysis. Experimental results are reported in the following examples. Materials:

[0093] Glucose, Raney-nickel (WR Grace Raney-nickel 2800), sodium tungstate (NaT), glycolic acid (GA), ethylene glycol (EG), 1,2-propylene glycol (PG), 1,2-butanediol (12BDO), glycerol were purchased from Sigma- Aldrich chemical company.

Analytical Methods:

[0094] In the Examples provided below, pH measurements were made using Thermo Scientific’s Orion Star A211 bench top pH meter and the meter was calibrated with standard buffer solutions in the 4-10 pH range.

[0095] HPLC analysis of the liquid samples was performed using the following method and conditions: Liquid Chromatography System - Shimadzu; Controller - SCL-lOAvp; Pump - LC-20AD; Degasser - DGU-20A 5r; Autosampler - SIL-10AF; Column Oven - CTO-20AC; UV detector - SPD-20AV; RI detector - RID-10A.

[0096] HPLC instrument conditions: Column: Bio-Rad Aminex HPX-87H (300 mm x 7.8 mm); Flow Rate: 0.6 ml/minute; Column Oven: 30C; Injection Volume: 10 pi; UV Detector: @320 NM; RI Detector: mode - A; range - 100; Run Time: 66 minute; Mobile Phase: 5 mM Sulfuric Acid in water.

[0097] Standard solutions containing glucose, sorbitol, ethylene glycol (EG), 1,2- propylene glycol (PG), 1,2-butanediol (12BDO), glycerol, erythritol, threitol, xylitol, etc. were prepared using water as the solvent at various concentrations. These solutions were analyzed to create the HPLC calibration curves. Samples were analyzed, with or without further dilution, and the calibration factors were applied to calculate the concentrations of the various products present in the experimental samples.

Example 1

[0098] Production of glycols from glucose using Raney-Ni, sodium tungstate, and glycolic acid and feeding the reactor either continuously or intermittently.

[0099] In this example, 30+/-0.3 grams of a sample of WR Grace Raney-nickel 2800 was added to the autoclave (Reactor 100) as slurry in 500-550 ml of water. The autoclave level control was set up to maintain the liquid holdup volume 120 in the reactor on average constant with continuous outflow. A continuous flow of hydrogen 1 was provided and the reactor pressure was controlled in the range of 1500 psig. Hydrogen flow rate was set at 25 standard liters per hour. [00100] Feed solutions were prepared using deionized water as solvent, containing 20.0% wt concentration of glucose and 0.50% wt concentration of sodium tungstate (NaT) as retro- Aldol catalyst, balance to a pH of 7.2 by adding glycolic acid. Liquid flow rate 2 was set constant at a certain value for a least a day. Subsequently the feed was moved to intermittent dosing at the same average dosing rate (pulsed dosing). The size of a pulse was chosen such that the concentration of the glucose assuming immediate mixing in the liquid bulk would reach a certain number. The stirrer 110 agitates the bulk liquid volume 120 to disperse the feed from lines 2 and 3 and may be designed as a sparger to keep the bulk liquid volume 120 close to saturation with hydrogen.

[00101] Samples of product stream 13 were analyzed by pH probe and HPLC to determine

pH and the concentrations of the various products. The experimental results are summarized in Table 1.

TABLE 1 Effect of Pulsed dosing on total glycols yield (=sum of MEG, MPG and 1,2- butanediol yield

[00102] As shown in Table 1 above, even though there is scatter between experiments, the impact of pulsed dosing in reducing total glycols yields is less in case the immediate concentration is lower. Diluting the feed more (i.e. lower immediate concentration) is therefore beneficial, even at these moderate glucose concentrations.

Example 2

[00103] A kinetic model was developed in order to accurately model the combined retro- aldol reactions. These reactions result in a range of products, including ethylene glycol, propylene glycol, 1,2-butanediol, 1,2-hexanediol, glycerol, erythritol, threitol and sorbitol. Known intermediates include glycolaldehyde, hydroxyacetone and l-hydroxy-2-butanone.

[00104] Reaction rates are not available in the literature for each individual reaction. Therefore, reaction rates were averaged on the basis of literature available (Zhang, J., Hou, B., Wang, A., Li, Z„ Wang, H„ Zhang, T„ AIChE Journal (2014) 60 (11) 3804-3813; Zhang, J„ Hou, B„ Wang, A., Li, Z„ Wang, H„ Zhang, T„ AIChE Journal (2015) 61 (1) 224-238), with the exception of hydrogenation of glycolaldehyde, which was assumed to be five times faster than the average rate of hydrogenation of all other ketone and aldehyde intermediates (referring to Mahfud, F.H., Ghijsen, F., Heeres, H.J., Journal of Molecular Catalysis A: Chemical (2007) 264 (1-2) 227-236).

[00105] The kinetic model was set up in Microsoft Excel 2010 and the respective pre exponential factors and activation energies were slightly adjusted to enable fitting of experimental data of glucose conversion during time at various temperatures. As a final check, concentrations and conditions provided in literature (Zhao, G., Zheng, M., Zhang, J., Wang, A., Zhang, T., Ind. Eng. Chem. Res. (2013) 52 (28) 9566-9572) were used as input, resulting in model predictions in reasonable accordance with the product yields reported.

[00106] The kinetic model was then used to predict the relevant timescale for mixing of the retro aldol reaction. In this example, the process was modelled as a plug flow or batch process, i.e. without dilution.

[00107] A feed stream comprising 40%w glucose and 3333 ppmw tungsten in water enters reaction zone where the temperature is raised to 230° C. Reaction times for retro-aldol reactions in reaction zone were varied as given in Table 2 and the intermediate compositions calculated assuming ideal plug flow behaviour with the kinetic model described above. Glucose conversion is higher than 99% and virtually complete after 1440 ms.

[00108] Yields are given in weight percent and calculated as weight of intermediate divided by weight of saccharide feed and multiplied by 100. Table 2 illustrates that mixing times below 2000 ms can be advantageous for reactor yields as degradation of feed (glucose) and intermediates (e.g. glycolaldehyde) is reduced significantly. Table 2 - Intermediate yields

*hydroxyacetone

* * 1 -hydroxybutanone

[00109] Other and further embodiments utilizing one or more aspects of the inventions described above can be devised without departing from the spirit of Applicant's invention. The order of steps can occur in a variety of sequences unless otherwise specifically limited. The various steps described herein can be combined with other steps, interlineated with the stated steps, and/or split into multiple steps. Similarly, elements have been described functionally and can be embodied as separate components or can be combined into components having multiple functions.

[00110] While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of examples herein described in detail. It should be understood, that the detailed description thereto are not intended to limit the invention to the particular form disclosed, but on the contrary, the intention is to cover all modifications, equivalents and alternatives falling within the spirit and scope of the present invention as defined by the appended claims.