METHOD FOR CARRYING OUT A CHEMICAL REACTION IN AN UPFLOW REACTOR

Abstract

The present invention relates to a method for carrying out a catalysed chemical reaction using one or more liquid reactants, preferably acetone and phenol, in an upflow reactor comprising feeding at least a portion of said reactants to a bottom section of the reactor positioned below a flow distributor plate, passing said portion through the flow distributor plate, passing said portion through a layer of inert particles positioned above and preferably in contact with said flow distributor plate, passing said portion through a catalyst layer comprising a particulate catalyst, said catalyst layer being positioned above and in contact with said layer of inert particles, wherein the reactants react to form a product stream, collecting said product stream via collecting means positioned above said catalyst layer. The invention also relates to a reactor assembly.

Claims

1. Method for carrying out a catalysed chemical reaction using one or more liquid reactants in an upflow reactor comprising: feeding at least a portion of said reactants to a bottom section of the reactor positioned below a flow distributor plate, passing said portion through the flow distributor plate, passing said portion through a layer of inert particles positioned above and in contact with said flow distributor plate, passing said portion through a catalyst layer comprising a particulate catalyst, said catalyst layer being positioned above and in contact with said layer of inert particles, wherein the reactants react to form a product stream, collecting said product stream via collecting means positioned above said catalyst layer, wherein, the upflow reactor is operated at a weight hourly space velocity of at least 1.0, and the inert particles have a density of at least 2000 kg/m3 and an average particle size of from 500 to 5000 m, and the particulate catalyst consists of catalyst particles having a density of at most 65% of the density of the inert particles and an average particle size, in use, of from 500 to 1500 m, the height of the layer of inert particles is at least 40 times the average particle size of the inert particles.

2. The method of claim 1 wherein the catalysed chemical reaction comprises the reaction between phenol and ketone, so as to form a product stream comprising bisphenol.

3. The method of claim 1 wherein the weight hourly space velocity is at least 1.2.

4. The method claim 1 wherein the liquid reactants consist of phenol and acetone, the product stream comprises bisphenol A, phenol, acetone, water and by products, wherein the amount of bisphenol A is from 15-35 wt. % based on the weight of the product mixture.

5. The method of claim 1 wherein the inert particles comprise, essentially consist or consist of particles selected from sand particles, glass particles, ceramic particles, diatomaceous earth particles, inert metal particles and combinations of at least two hereof.

6. The method of claim 1 wherein the catalyst is a cross-linked polystyrene based ion-exchange resin type catalyst.

7. The method of claim 1 wherein the distributor plate is a slotted plate with a plurality of openings having a size smaller than the average particle size of the inert particles and preferably having a size from 50 to 500 m.

8. The method of claim 1 wherein the distributor plate has a porosity of 10-50%, porosity being defined as the percentage of open area relative to the surface area in flow direction of the distributor plate.

9. The method of claim 1 wherein the height of the layer of inert particles is at least 2.0 cm.

10. The method of claim 1 wherein the reactor is substantially cylindrical in shape.

11. The method of claim 1 wherein the liquid reactants consist of phenol and acetone, the product stream comprises bisphenol A, phenol, acetone, water and by products, wherein the amount of bisphenol A is from 20-30 wt. % based on the weight of the product mixture.

12. A reactor assembly for carrying out a catalysed chemical reaction using one or more liquid reactants in upflow comprising: feeding means for feeding at least a portion of said reactants to a bottom section of the reactor, said feeding means being positioned below a flow distributor plate, a layer of inert particles positioned above and in contact with said flow distributor plate, a catalyst layer comprising a particulate catalyst positioned above and in contact with said layer of inert particles, collecting means positioned above said catalyst layer for collecting a product stream from the reactor, wherein, the inert particles have a density of at least 2000 kg/m3 and an average particle size of from 500 to 5000 m, and the particulate catalyst consists of catalyst particles having a density of at most 65% of the density of the inert particles and an average particle size, in use, of from 500 to 1500 m, the height of the layer of inert particles is at least 40 times the average particle size of the inert particles.

13. The reactor assembly of claim 12 for carrying out the method in accordance with claim 1.

14. The method of claim 1, wherein the particulate catalyst consists of catalyst particles having a density of at most 50% of the density of the inert particles.

15. The method of claim 1, wherein the catalysed chemical reaction comprises the reaction between phenol and acetone so as to form a product stream comprising bisphenol A.

16. The method of claim 1, wherein weight hourly space velocity is from 1.5 to 5.0, or from 1.7 to 3.0.

17. The method of claim 1, wherein the catalyst is a cross-linked polystyrene based ion-exchange resin type catalyst and comprises an attached promotor.

18. The method of claim 1, wherein the distributor plate is a slotted plate with a plurality of openings having a size smaller than the average particle size of the inert particles and having a size from 150 to 300 m.

19. The method of claim 1, wherein the height of the layer of inert particles is at least 2.5 cm.

20. The method of claim 1, wherein the height of the layer of inert particles is at least 3.0 cm.

Description

[0048] The present invention will now further elucidated herein on the basis of the following non-limiting examples and Figures.

[0049] FIG. 1, not to scale, is a partial cross-sectional view of an exemplary reactor assembly 10 of the present disclosure. In general, reactor assembly 10 is a packed bed reactor assembly that is configured and dimensioned to produce dihydroxy compounds (e.g., bisphenols, preferably bisphenol A). Reactor assembly 10 includes a distributor unit 20 having a plurality of distributor pipes (e.g., four distributor pipes) with holes or perforations pointing downward, with the plurality of distributor pipes 20 forming a distributor unit positioned evenly across the cross-section of the vessel 14 of reactor assembly 10.

[0050] Above the distributor unit, a distributor plate 17 (e.g., a slotted plate or wire mesh plate with openings having a size from 50 to 500 micrometers, preferably from 150 to 300 micrometers) is positioned to support the layer of inert particles 13 and the catalyst layer 12. The feed to the reactor assembly 10 via distributor pipes 20 of the distributor unit includes phenol and acetone. From the pipes 20 the liquid feed is injected predominantly in a direction away from the distributor plate 17.

[0051] The inert layer, i.e. layer with inert particles 13 is positioned on or above distributor plate 17 to help distribute the feed from the distributor unit uniformly to the catalyst layer 12.

[0052] The inert layer 13 can comprise, without limitation, sand particles, glass particles, silica particles, metal particles (e.g., metal particles that are inert in the feed mixture, such as, for example, nickel particles and/or titanium particles), or a combination comprising at least one of the foregoing. The height of the inert layer 13 (e.g., sand layer 13) on top of distributor plate 17 in vessel 14 can be on average 2.5 cm.

[0053] A lower limit for the height of the inert layer 13 on top of distributor plate 17 can be about 2 cm. However, it is noted that the height of the layer 13 on top of distributor plate 17 can be 4 cm to 5 cm. It is noted that there may be no significant benefit having a height of the layer 13 on top of distributor plate 17 greater than 10 cm.

[0054] The particles (e.g., sand particles) of layer 13 can have an average particle size from 700 to 1200 m.

[0055] In use, a catalyst layer 12 can be disposed on the inert layer 13 (layer of inert particles), said catalyst layer 12 including ion exchange resin particles (e.g., acidic ion exchange resin catalyst particles), the ion exchange resin particles optionally comprising an attached promoter (e.g., co-catalyst promoter).

[0056] For the avoidance of doubt it is noted that the flow direction in reactor assembly 10 is from bottom to top , i.e. from distributor pipes 20 to collecting means 30.

[0057] Collecting means 30 for collecting the product mixture from reactor assembly 10 are positioned above catalyst layer 12. The exact location of said collecting means may vary.

[0058] In an embodiment a further product distribution plate (not shown) may be positioned above catalyst layer 12. Such a product distribution plate is optionally in direct contact with the catalyst layer. The porosity of such a distribution plate is preferably the same or higher than the porosity of the distributor plate. Preferably the product distributor plate is a slotted plate with a plurality of openings having a size smaller than the average particle size of the catalyst particles and preferably having a size from 300-1000 m, preferably from 500-800 m. The product distributor plate, in particular when in contact with the catalyst layer 12 further supports the catalyst bed stability and may be used to prevent catalyst particles to end up in the collecting means. A combination of several product distributor plates may be used.

[0059] The product mixture typically contains bisphenol A, acetone, phenol, water and impurities or byproducts. The product mixture is further processed in downstream process steps to isolate and purify the bisphenol A product. Such steps are known to a skilled person.

[0060] In a specific aspect the present invention relates to a method for carrying out a catalysed chemical reaction for the manufacture of bisphenol A using one or more liquid reactants in an upflow reactor comprising: [0061] feeding at least a portion of said reactants to a bottom section of the reactor positioned below a flow distributor plate, said reactants comprising acetone and phenol, [0062] passing said portion through the flow distributor plate, [0063] passing said portion through a layer of inert particles positioned above and preferably in contact with said flow distributor plate, [0064] passing said portion through a catalyst layer comprising a particulate acidic ion exchange resin catalyst optionally comprising an attached promotor, said catalyst layer being positioned above and in contact with said layer of inert particles, wherein the reactants react to form a product stream comprising bisphenol A, [0065] collecting said product stream via collecting means positioned above said catalyst layer, [0066] wherein, [0067] the upflow reactor is operated at a weight hourly space velocity of at least 1.0, and [0068] the inert particles have a density of at least 2000 kg/m3 and an average particle size of from 500 to 5000 m preferably from 500 to 3000 m, more preferably from 600 to 1500 m, and [0069] the particulate catalyst consists of catalyst particles having a density of from 800 to 1200 kg/m.sup.3 and an average particle size, in use, of from 500 to 1500 m, [0070] the height of the layer of inert particles is at least 40 times the average particle size of the inert particles.

[0071] The preferred features as described herein more generally equally apply to the method of this specific aspect.

EXAMPLES 1-7

[0072] Experiments were conducted using the configuration of the reactor assembly 10 as shown in FIG. 1. Reactor assembly 10 included a distributor unit having four distributor pipes 20 with holes or perforations pointing downward, with the four distributor pipes of distributor unit 20 positioned evenly across the cross-section of vessel 14.

[0073] Vessel 14 had an inner diameter of 800 millimeters (mm). The tangent to tangent height of vessel 14 of 2000 mm was sufficient to contain the catalyst volume of catalyst layer 12 and provided sufficient empty space for proper liquid collection using suitable collecting means 30. Above the distributor unit, a distributor plate 17 was positioned. Distributor plate 17 was a slotted plate with openings having a diameter of 200 m.

[0074] An amount of 0.50 m 3 of ion-exchange resin catalyst formed catalyst bed 12.

[0075] The ion-exchange resin catalysts for catalyst bed 12 used in the experiments were commercially available 2% cross-linked sulfonated polystyrene which differed in particle size distribution.

[0076] Catalyst Type 1 had a poly-disperse particle size distribution with a ratio of D90/D10 of about 1.4 and with an average particle size of about 1065 m.

[0077] Catalyst Type 2 had a mono-disperse particle size distribution with a ratio of D90/D10 of about 1.1 and with an average particle size of about 875 m.

[0078] The particle size and particle size distribution was determined via an image analysis technique.

[0079] Table 1 shows results of experiments carried out at different flow speeds, representative for the amount of material flowing through the reactor and accordingly for the WHSV. The feed consisted of a mixture of 5 wt. % acetone and 95 wt. % phenol and catalyst type 2 was used. The sand layer in examples E1-E3 consisted of sand particles obtained by sieving of river sand and having a particle size distribution from 0.7 to 1.2 mm, and a bulk density of 1.58 kilogram/liter (kg/l). The height of the sand layer 13 on top of distributor plate 17 in vessel 14 was on average 2.5 cm. The average particle size of the sand particles was about 1000 m. The density of the sand particles of sand layer 13 was about 2500 kg/m.sup.3.

TABLE-US-00001 TABLE 1 E1 E2 E3 CE1 CE2 CE3 Flow_speed [mm/s] 0.133 0.200 0.267 0.133 0.200 0.267 WHSV 1.0 1.5 2.0 1.0 1.5 2.0 Acetone conversion [%] 94.5 89.6 74.5 96.3 85.9 71.8 ppBPA Selectivity [%] 94.0 93.7 93.7 94.0 94.6 94.0 Feed temperature [ C.] 55 55 60 55 55 60 Sand layer yes yes yes no no no Catalyst type 2 2 2 2 2 2

[0080] The flow speed corresponds to the upward linear velocity of the flow in the void reactor area (e.g., the area above catalyst bed 12) of vessel 14 and is defined as the volumetric flowrate divided by the cross-sectional area of the vessel 14 of the reactor assembly 10.

[0081] The acetone conversion represents the weight percent of acetone that is converted during the reaction and based on measurement of the acetone concentration in the outlet of the reactor.

[0082] The p,p-bisphenol A (ppBPA) selectivity represents the weight percentage of p,p-bisphenol A that was produced relative to the total amount of bisphenols.

[0083] From Table 1 it can be observed that upon increasing flow speed the acetone conversion decreases when no sand bed (layer of sand) is present. The present inventors believe this was due to an uncontrolled and less homogenous flow through the catalyst layer and may either one or more of catalyst fluidisation and/or back mixing and/or channeling.

[0084] Table 2 shows the results of experiments that were carried under the same conditions except that catalyst type 1 was used and the concentration of acetone in the feed was 3 wt. % (and the phenol concentration accordingly was 97 wt. %)

TABLE-US-00002 TABLE 2 E4 E5 CE4 CE5 Flow_speed [mm/s] 0.133 0.267 0.133 0.267 WHSV 1.0 2.0 1.0 2.0 Acetone conversion [%] 98.2 93.1 96.2 88.7 ppBPA Selectivity [%] 95.1 95.9 945.4 94.7 Feed temperature [ C.] 55 55 55 55 Sand layer yes yes no no Catalyst type 1 1 1 1

[0085] Table 3 shows the results of further experiments wherein the feed contained fresh acetone and phenol but also a recycle stream containing unreacted acetone and phenol, p,p-bisphenol-A (also known as 2,2-bis(4-hydroxyphenyl)propane or ppBPA)), o,p-bisphenol A (also known as 2,4-isopropylidenediphenol (opBPA)) and/or other isomers. Catalyst type 1 was used; the sand layer (if present) was the same as for the Examples in Tables 1 and 2.

[0086] The composition of the feed in the experiments E6/CE6 and E7/CE7 consisted of [0087] 3 wt. % of acetone [0088] 74.5 wt.% of phenol [0089] 12 wt. % of p,p-bisphenol A [0090] 3.5 wt. % of o,p-bisphenol A [0091] 7 wt. % other isomers including one or more of, 3-(4-hydroxyphenyl)-1,1,3-trimethyl-2H-inden-5-ol (cyclic dimer 1); 2,4-bis[1-(4-hydroxyphenyl)isopropyl]phenol (BPX 1); 4-(2,2,4-trimethylchroman-4-yl)phenol (chroman 1); 4-(2,4,4-trimethyl-3,4-dihydro-2H-chromen-2-yl)phenol (chroman 1.5); 1,1-spirobi[1H-indene]-6,6-dio1,2,2,3,3-tetrahydro-3,3,3,3-tetramethyl (spirobiindane).

[0092] The viscosity of this feed was significantly higher compared to the feed in the experiments in Tables 1 and 2.

TABLE-US-00003 TABLE 3 E6 E7 CE6 CE7 Flow_speed [mm/s] 0.133 0.267 0.133 0.267 WHSV 1.0 2.0 1.0 2.0 Acetone conversion [%] 95.2 65.2 77.1 44.6 ppBPA Selectivity [%] 98.4 98.8 101.2 103.2 Feed temperature [ C.] 62.8 63.2 56 63.4 Sand layer yes yes no no Catalyst type 1 1 1 1

[0093] Because of the presence of isomers in the feed, which may be converted into p,p-bisphenol A, the ppBPA selectivity could be over 100%.

[0094] Since the feed in the Examples of Table 3 has a significantly higher viscosity (about 2.5 times higher) compared to the Examples in Tables 1 and 2, the settling rate of the catalyst particles in the feed medium was higher, explaining a larger effect on the acetone conversion. Additionally and as mentioned, because this feed also contains products that can be converted by the catalyst into ppBPA (e.g., isomerisation of o,p-bisphenol A) the net calculated ppBPA selectivity % can be above 100%.

[0095] By means of computational fluid dynamics simulations the present inventor confirmed that advantageous effect of the sand layer. For a reactor equipped with a tri-slot distributor plate having 1.8 mm width bars with 0.2 mm clearance between them they found that at a WHSV of 2 they observed that without a sand layer significant channeling and/or back mixing occurred in the catalyst layer. When the catalyst layer was put on top of a sand layer of about 5 cm the channeling and back mixing was reduced to a minimum and a more even fluid velocity pattern was observed.