Method for feeding catalyst in a reactor

Abstract

The present invention relates to a method for introducing catalyst beads in a reactor comprising the steps of a) providing at least one first container comprising a mixture of catalyst beads and a first aqueous composition, b) transferring at least part of the mixture of step a) to a second container and diluting the mixture with a second aqueous composition c) transferring the diluted mixture to the reactor.

Description

[0001] METHOD FOR FEEDING CATALYST IN A REACTOR

[0002] The present invention relates to a method for introducing catalyst beads in a reactor from at least one first container comprising a mixture of catalyst beads and a first aqueous composition. More specifically, the present invention relates to a method for introducing ion-exchange resin catalyst beads in a reactor.

[0003] Chemical reactions catalysed by ion-exchange resin catalyst in a liquid phase are well known to the skilled person. One of the most well known processes using this catalyst technology concerns the manufacture of bisphenol A. That is, bisphenol A is manufactured by feeding a feed composition comprising acetone and phenol to a reactor comprising an ion-exchange resin catalyst and reacting the acetone and phenol to bisphenol A.

[0004] A problem with ion-exchange resin catalysts, as with many other catalysts, is that their activity or productivity decreases over time, mainly caused by contaminants in the feed to the reactor that deactivate the catalytic sites on the catalyst beads. Accordingly there is a need to replace catalyst beds of ion-exchange resin beads from time to time, which typically is a time consuming activity and leading to significant down-time of the reactor.

[0005] The transport of ion-exchange resin catalysts from the manufacturer to the end-user may be in the form of a composition comprising the catalyst beads and an aqueous composition. For example, a slurry of ion-exchange resin catalyst beads may be shipped in an intermediate bulk container (IBC).

[0006] The amount of catalyst required for a typical industrial scale reactor is such that it requires the handling of many IBCs. That is, if a new catalyst bed needs to be installed in a reactor the contents of a large amount of IBCs needs to be transferred. Since the reactor itself, or at the least its opening for the introduction of catalyst, is typically located several meters above the ground this means that the introducing the catalyst may involve a significant amount of hoisting the IBCs to a level where its contents can more easily be fed or discharged into the reactor. Since catalyst beads, and in particular ion-exchange resin catalyst beads, are quite sensitive and prone to damage they cannot be pumped from the IBC into the reactor at all, or at least only out under economically unfeasible conditions.

[0007] US 10,946,357 discloses a process for feeding a polymerisation catalyst into a polymerisation reactor, comprising the steps of: (i) maintaining a catalyst slurry comprising a diluent and a solid catalyst component in a catalyst feed vessel; (ii) continuously withdrawing a stream of the catalyst slurry from the catalyst feed vessel; and (iii) introducing the withdrawn portion of the catalyst slurry into the polymerisation reactor, wherein the catalyst slurry is transferred by using a valveless piston pump from the catalyst feed vessel into the polymerisation reactor; the diluent has a dynamic viscosity of from 0.01 to 20 mPas at the conditions within the catalyst feed vessel, and wherein the catalyst slurry is transferred along a substantially vertical path downwards from the catalyst feed vessel to the reactor.

[0008] EP 2263794 discloses a method for regenerating acidic cation exchangers, which are used as catalysts in the reaction of phenols with aldehydes or ketones to give bisphenols, in particularto give bisphenol A, with acids, with the proviso that, in the method according to the invention, these cation exchangers experience very little mechanical damage due to swelling processes during the regeneration process.

[0009] In view of the foregoing it is an object of the invention to simplify the process of introducing fresh catalyst beads into a reactor. More in particular it is an object of the present invention to provide for a method of introducing resin catalyst beads in a reactor that requires less handling, is improved in terms of safety and is faster, while at the same time any damage to the catalyst beads as a result of the introduction is reduced to a minimum.

[0010] This object is met, at least in part with the method in accordance with the present invention.

[0011] Thus the present invention provides for a method for introducing catalyst beads in a reactor comprising the steps of a) providing at least one first container comprising a mixture of catalyst beads and a first aqueous composition, b) transferring at least part of the mixture of step a) to a second container and diluting the mixture with a second aqueous composition, c) transferring the diluted mixture to the reactor.

[0012] Typically the first container consists of a mixture of catalyst beads and said first aqueous composition. Likewise the second container, after dilution, will consist of the catalyst beads, the first aqueous composition and the second aqueous composition.

[0013] While the present invention was conceived within the context of transporting ion exchange resin catalyst, the present inventors consider that the principle underlying the invention is generally applicable to any type of solid catalyst that is contained in an aqueous composition. Nonetheless and more in particular the present invention is directed at a method for introducing catalyst beads in a reactor comprising the steps of a) providing at least one first container comprising a mixture of catalyst beads and a first aqueous composition, b) transferring at least part of the mixture of step a) to a second container and diluting the mixture with a second aqueous composition, c) transferring the diluted mixture to the reactor, wherein the catalyst beads comprise or consist of ionexchange resin catalyst beads, more preferably polystyrene-based ion-exchange resin beads.

[0014] The present inventors have found that if the concentration of the catalyst beads in the first aqueous composition is reduced, practically by means of dilution, the catalyst can be transferred without loss of quality in terms of damage. The present inventors found that this dilution allows for the transport under low shear conditions.

[0015] While the term “low shear” is considered to be understood by the person skilled in the art, in the context of the present invention the term is meant to conditions of transferring the diluted mixture such that the catalyst beads substantially remain in tact and do not get damaged as a result of such transferring. The inventors submit that such low shear conditions are obtained if the amount of collisions between catalyst beads is reduced to a minimum and / or if the energy of such collisions is reduced to a minimum. If such collisions would lead to extensive damage of the catalyst beads then this results in small and typically irregularly shaped particles, which are referred to as fines. Effective low shear conditions are obtained if the amount of fines generated during the transferring of the diluted mixture to the reactor is increased by at most 5 wt.%, preferably at most 2 wt.%, more preferably at most 1 wt.% or 0.1 wt.% compared to the amount of fines in the first container(s) and prior to transfer to the second container. Fines in particular refer to the fraction of particles obtained by sieving that corresponds to at most 80% of the specified average diameter of the catalyst beads. Thus, by way of example, if the average catalyst bead diameter specification is 1000 pm, then the amount of fines refers the fraction that is obtained using sieving with a sieving pore size of 800 pm.

[0016] Typically, the transfer of the mixture of step a) into a second container does not involve a significant amount of shear, if at all, so that the amount of fines that are formed during the transfer of the mixture of step a) into the second container is reduced to a minimum.

[0017] Preferably the transferring in step b) is carried out by pouring the mixture contained in the first container through an opening in said first container into the second container, or by allowing the mixture contained in the first container to flow under gravity from an opening in said first container and into said second container. Optionally a funnel and / or a piping system receiving the mixture from the first container may be used. It is preferred that no mechanical means, such as in particular pumps, are used for the transferring in step b).

[0018] In order for allowing the transfer in step b) to take place under gravity, the outlet of the first container is located lower than the inlet of the second container.

[0019] In accordance with the invention it is preferred that the transferring in step c) is carried out under low shear conditions. Such low shear conditions can be obtained in several ways. For example, the more the mixture of step a) is diluted, the less probable it is that catalyst beads collide and / or the lower the collision energy may be. Another important factor is the flow rate of transfer in step c). Large diameter pipes require a lower flow rate per unit of cross-sectional area of the pipe which results in less shear.

[0020] In a practical implementation of the present invention one or more pumps are required for transferring the diluted mixture in step c). Such pumps are preferably so-called low- shear pumps, which in itself are well know to a skilled person. Either way, and given the definitions above, the skilled person can objectively determine whether any selected transferring system including said one or more pumps, the piping and any other required equipment results in the required low-shear conditions. In order to avoid damage of the catalyst beads it is preferred that the diluted mixture is transferred to the reactor using a low-shear pump at a rate of from 2 - 20 m3 / hr, preferably from 5 - 10 m3 / h using a pipe or hose with an internal diameter of from about 0.05 - 0.08 m. More in general it is preferred that the cross sectional speed through a conduit, i.e. a pipe or hose, is at most 3 m / s, preferably at most 2.5 m / s, more preferably at most 2 m / s. While there is no critical lower limit for such cross-sectional speed a skilled person will appreciate that very low speeds result in a more slow process, depending of course also on the diameter of the conduit, and hence the introduction of new catalyst in the reactor will take longer. Lower limits may accordingly be 0.1 , 0.3 or 0.5 m / s.

[0021] It is preferred that the diluting is carried out during the transferring from the first container to the second container, in the second container or both during said transferring and in said second container. For example, to the extent a funnel or any sort of piping is used to allow the transfer from the first container to the second container, said funnel or said piping may be in fluid connection with means for adding the second aqueous composition, which is typically water. Typically after the first container is emptied, said container is rinsed with second aqueous composition in order to clean the first container from any remaining catalyst beads, and said second aqueous composition, together with any residual catalyst beads or first aqueous composition flows into the second container. For the purpose of the present invention the dilution resulting from such a rinsing step is to be considered as diluting carried out in the second container.

[0022] Typically an amount of second aqueous solution used for rinsing of the first container amounts from 1 to 10 %, preferably 2 to 8%, more preferably 3 to 7 % of the volume of the first container. Typically, for first containers having an internal volume of about 1 m3the amount of second aqueous solution is from 10 - 100 liter such as for example from 20 - 50 liter. The exact amount depends on the amount of catalyst beads sticking to the internal walls of the first container after it is emptied into the second container.

[0023] In addition or in the alternative the second aqueous composition can be added directly to the second container. A preferred method of dilution comprises injecting the second aqueous solution in the second container such that the mixture in the second container, in particular the catalyst beads, is / are not allowed to settle. Thus by appropriately injecting the second aqueous solution into the second container a certain circulation or flow is maintained in the second container thereby allowing for a more homogeneous concentration of catalyst beads in the second container.

[0024] It is preferred that the dilution in the second container and the transfer of the diluted mixture to the reactor is carried simultaneously. In a specific embodiment at least two first containers each comprising a mixture of catalyst beads and a first aqueous composition is transferred to a second container, followed by diluting the mixture in the second container with a second aqueous composition while simultaneously transferring the diluted mixture to the reactor.

[0025] The dilution of the mixture of catalyst beads and first aqueous composition, defined as is preferably from 1.01 to 5.00, more preferably from 1.10 - 3.00, even more preferably from 1.30 - 2.50. In the above formula Vi corresponds to the volume of the diluted mixture andocorresponds to the volume of the mixture of catalyst beads and first aqueous composition. For the sake of clarity and by way of example, if the mixture of catalyst beads and first aqueous composition is 1000 liter and an amount of 250 liter as the second aqueous composition would be added then the dilution is (1000 + 250) / 1000 = 1.25.

[0026] For the avoidance of doubt it is noted that if the dilution is carried out during the transport from the first container to the second contaner, that i corresponds to the volume of the so obtained diluted composition in the second container. If dilution is carried out both during transport and in the second container than i also corresponds to the volume of the so obtained diluted composition in the second container. Further to the foregoing, when approaching the dilution from a process point of view the dilution is the ratio of the volumetric flow of the diluted composition and the flow of the composition from the first container (i.e. catalyst and first aqueous composition). The first aqueous composition is preferably a monophasic solution and accordingly does not contain any solids or any water insoluble components. The first aqueous composition dilution preferably consists of water, more preferably de-ionised water. Preferably the water of aqueous composition is de-ionised water, preferably having an electrical conductivity of at most 5 pS / cm at 25°C measured in accordance with ISO 7888:1985.

[0027] The second aqueous composition is preferably a monophasic solution and accordingly does not contain any solids or any water insoluble components. The second aqueous composition dilution preferably consists of water, more preferably de-ionised water. Preferably the water of aqueous composition is de-ionised water, preferably having an electrical conductivity of at most 5 pS / cm at 25°C measured in accordance with ISO 7888:1985.

[0028] It is preferred that the water either or both of the first and second aqueous phase is deoxygenated, meaning that the aqueous phase contains at most 0.5 mg / l of molecular oxygen, O2

[0029] It is preferred that the de-ionised water has a conductivity at most 5 pS / cm at 25°C measured in accordance with ISO 7888:1985, a calcium content of at most 1 ppb, a chloride content of at most 50 ppb, a sulfate content of at most 50 ppb, a silica (SiO2) content of at most 0.1 ppb, a magnesium content of at most 1 ppb, a sodium content of at most 200 ppb and a potassium content of at most 100 ppb, wherein the ppb refers to ppb by weight.

[0030] Any nitrogen used in the method of the invention preferably has a dew point of at most - 60 °C and a purity of at least 99.99 vol%. The oxygen content of the nitrogen is preferably at most 10 ppm by volume.

[0031] It is preferred that the oxygen concentration in the water, in particular the water for dilution is reduced to a minimum because oxygen may, at least partially, deactivate the catalyst.

[0032] In order for the method in accordance with the invention to be carried out in an economically viable way it is preferred that the second container has a volume of from 2 to 20 times, preferably 3 to 10 times the volume of the first container. Preferably the first container has an interval volume of from 0.75 - 1.5 m3, preferably from 0.90 - 1.1 m3and the second container has an internal volume of from 2.0 - 8.0m3, preferably 3.0 - 5.0 m3.

[0033] The catalyst beads preferably comprise or consist of an ion exchange resin, preferably an ion exchange resin for catalysing the reaction between a ketone and a phenol to form a bisphenol. Put differently, the catalyst beads of the present invention are preferable ion-exchange resin catalyst beads. In the context of the present invention the ion exchange resin is a catalyst for the reaction of acetone and phenol to form bisphenol A.

[0034] Ion exchange resins, and more specifically these ion exchange resin catalysts are known per se and are typically prepared by polymerising styrene, optionally in the presence of a crosslinking agent such as divinyl-benzene, followed by a step of sulfonating the resin by exposing the formed optionally crosslinked polystyrene beads to a sulfonic acid. The resin may further be modified to comprise functional groups that promote the formation of p,p - bisphenol A over o,p - bisphenol A. Technologies for the manufacture of such ion exchange resin catalysts are well known to the skilled person. It is preferred that the catalyst beads comprise or consist of sulphonated crosslinked polystyrene ion exchange resin beads

[0035] The catalyst beads, in the mixture of catalyst beads and a first aqueous composition, preferably have an average diameter of from 200 - 3000 pm.

[0036] The average diameter of the catalyst beads is preferably 200 pm or more, such as 300 pm or more, 400 pm or more, 500pm or more, or 600 pm or more. The average diameter of the catalyst beads is preferably 3000 pm or less, such as 2500 pm or less, 2200 pm or less, 2000 pm or less, 1800 pm or less, or 1600 pm or less. The average diameter of the catalyst beads is preferably from 500 - 2500 pm, more preferably from 750 - 1500 pm. The average diameter of the catalyst beads can be determined using known methods, e.g., commonly known microscopy methods, automated imaging, laser diffraction and sieving techniques. The average diameter is a numerical average. Preferably microscopy is used as the technique for determining the average diameter. A preferred method is optical microscopy combined with imaging software to analyse the particle size and, if applicable, particle size distribution. The catalyst beads are substantially spherical in shape meaning that a ratio D_max / D_min is in the range of from 0.85 -1.15, preferably from 0.95 - 1.05, more preferably 0.98 - 1.02, wherein D_max is a maximum diameter measured on the particle (i.e. the bead) and D_min a minimum diameter measured on the particle. Generally D_max / D_min will be from 0.99 - 1.01. Most preferably D_max / D_min is 1 .00.

[0037] For the avoidance of doubt it is noted that the particle size of the catalyst beads corresponds to the particle size measured when the catalyst beads are in water swollen state, as will be understood by a person skilled in the art. This state corresponds to the state of the catalyst beads in the first and second container. Ion-exchange resin catalysts for the catalysis of the reaction between phenol and acetone to manufacture bisphenol A are known to absorb a rather large quantity of water, typically in the order of 70 - 85 wt%. As a result the dry and freshly produced ion-exchange resin beads will swell substantially when in contact with water.

[0038] In a typical situation the second container, and accordingly its outlet, is located below an inlet of the reactor for receiving the diluted mixture comprising the catalyst beads.

[0039] Although the present invention is not strictly limited in this respect, the first container typically has an internal volume of from 0.75 - 1.5 m3, preferably from 0.90 - 1.1 m3.

[0040] A typical concentration for the amount of catalyst in the first container is from 500 - 800 kg / m3, preferably 600 - 750 kg / m3Thus, by way of example, a first container with a volume of 1 m3completely filled may contain from 500 to 800 kg of catalyst beads and 500 to 200 kg of first aqueous solution, assuming the density of the first aqueous solution is substantially identical to the density of water. For the avoidance of doubt it is noted that the weight of the catalyst beads corresponds to the weight of the water swollen catalyst beads as will be understood by a person skilled in the art.

[0041] A typical reactor may require an amount of catalyst corresponding to

[0042] The reactor may be a downflow reactor or an upflow reactor, preferably a downflow reactor. The term downflow reactor is known to the skilled person and typically refers to a reactor where reactants are fed from the top of the reactor and reaction product is collected from the bottom. An advantage of such a reactor is that the flow through the reactor and the collection of products is supported, at least in part, by gravity. An upflow reactor is also known to a skilled person and typically refers to a reactor where reactants are fed from a bottom of the reactor and reaction product is collected from the top. An advantage of such a reactor is that the flow through the reactor can be more accurately controlled. In both upflow as downflow reactors the catalyst beads are supported on a porous catalyst support layer which is permeable to reactants and reaction products, but substantially impermeable to the catalyst beads. Such support layers are well known to the skilled person.

[0043] In the method of the invention the diluted mixture of catalyst beads is introduced in the reactor. In an embodiment where such introducing is performed with support of gravity it is preferred that the diluted mixture passes over a sieve located just before a catalyst feeding position of the reactor. For example, the sieve may be affixed, either temporarily or permanently to a catalyst feeding opening of the reactor. The sieve has the purpose to separate at least part of the second aqueous solution from the catalyst beads just prior to said catalyst beads being introduced in the reactor. Accordingly the pore size of the sieve is such that only the second aqueous solution and optionally a fraction of fines (if any) will pass through it thereby achieving the desired separation. The pore size of this sieve is preferably at most 80%, more preferably at most 50% of the average catalyst bead diameter. In the context of the present invention this means that such a sieve is not followed by any mechanical means for transferring the catalyst beads.

[0044] The present invention further relates to a system for carrying out the method disclosed herein, which comprises i) an unloading station equipped to receive the at least one first container, ii) at least one second container, iii) passive transferring means for transporting the mixture of said at least one first container into the at least one second container by pouring or by gravity, iv) dilution means for diluting the mixture of catalyst beads and first aqueous composition in said at least one second container or in said passive transferring means, v) one or more reactors, vi) means for transporting the diluted mixture in the at least one second container to said one or more reactors under low shear conditions.

[0045] Within the context of the present invention the term unloading station to be understood as a location and the corresponding equipment to unload one or more of the first containers. That is, the unloading station comprises means to receive one or more first containers and meand to unload the mixture of catalyst beads and first aqueous composition from said first container(s). Typically the first containers are what is commonly referred to as Intermediate Bulk Containers, or IBCs. Typically these are containers with a volume of from 0.75 to 1.5 m3, preferably from 0.9 to 1.1 m3, as explained also above.

[0046] Within the context of the present invention the term “passive transferring” means that the mixture in the first container is essentially taken out under the influence of gravity. In practice, if the first container has an opening (e.g. a valve) at the bottom, it is sufficient to imply open the valve. However, if the opening would be located at the top of the first container then the container needs to be rotated such that the container can be emptied, again under the influence of gravity.

[0047] The present invention further refers to a method for starting up a reactor for the manufacture of bisphenol, preferably bisphenol A, comprising i) adding to a reactor ion-exchange resin beads in accordance with the method disclosed herein thereby forming a layer of catalyst beads inside said reactor, ii) washing the catalyst bed with water, preferably de-ionised and deoxygenated water as disclosed herein, iii) continuously reacting a ketone and a phenol in said reactor and catalysed by said ion-exchange resin catalyst so as to form a bisphenol, wherein preferably the ketone is acetone and the phenol is phenol.

[0048] Following the washing in step ii) the catalyst bed is preferably dehydrated using one or more of a phenol, preferably phenol.

[0049] The appended Figure schematically shows a system for implementation for the method disclosed herein. De-ionised water 1 is fed to stripping column 3 and de-oxygenated and is stripped therein from oxygen by feeding nitrogen 2 from the bottom of the column 3. The nitrogen 2 may have a temperature in the range of 15 to 40 °C and is preferably from 20-30 °C. The mixture of nitrogen and oxygen that is removed from the water 1 is removed from the column by suitable means (not shown).

[0050] A mixture of ion exchange resin and an aqueous solution, typically provided in 1m3containers is fed to a buffer tank 6 from unloading station 5. Preferably the procedure is carried under a nitrogen blanket so as to avoid too much ambient oxygen to be introduced into the buffer tank 6. In buffer tank 6 the ion exchange resin catalyst mixture is diluted using the de-ionised and de-oxygenated water 4 from column 3. In an alternative arrangement the de-ionised and de-oxygenated water 4 is provided from a dedicated tank or existing supply means (both not shown). The catalyst from the first containers, i.e. the 1 m3containers is transferred to buffer tank 5 using only gravity.

[0051] In case the catalyst in downflow reactor 8 needs to be replaced the old catalyst is taken out by known procedures and thereafter fresh catalyst is introduced from buffer tank 6 into the reactor by means of low-shear pump 7. Noting that the Figure is not drawn to scale this catalyst transfer procedure can be carried out substantially in a continuous matter and prevents having to hoist and empty a large number of small containers, such as the 1 m3containers mentioned above, to the catalyst feed location at an upper section of reactor 8. After a desired level of catalyst is introduced in reactor 8 the catalyst bed can be washed and conditioned for further use. In order to clean the piping connecting the low-shear pump 7 with the reactor, the washing step may be carried out by connecting the supply side of pump 7 to a water supply source, preferably de-ionised and de-oxygenated water, and then pump 7 is used to support the washing procedure of the freshly introduced catalyst in reactor 8. Following the cleaning of the pipe connecting the low shear pump 7 and the reactor the catalyst bed in the reactor may be dehydrated using known methods such as for example washing with phenol.

Claims

C L A I M S1 . Method for introducing catalyst beads in a reactor comprising the steps of a. providing at least one first container comprising a mixture of catalyst beads and a first aqueous composition, b. transferring at least part of the mixture of step a) to a second container and diluting the mixture with a second aqueous composition, c. transferring the diluted mixture to the reactor.

2. The method of claim 1 or 2 wherein the transferring in step c) is carried out under low shear conditions, preferably using one or more low-shear pumps.

3. The method of any one or more of claims 1 - 2 wherein the diluting is carried out during the transferring from the first container to the second container, in the second container or both during said transferring and in said second container.

4. The method of any one or more of claims 1 - 3 wherein the catalyst beads comprise or consist of an ion exchange resin, preferably an ion exchange resin for catalysing the reaction between a ketone and a phenol to form a bisphenol.

5. The method of claim 4 wherein the catalyst beads in said first container have an average diameter of from 200 - 3000 pm preferably from 500 - 2000 pm6. The method of any one or more of claims 1 - 5 wherein the 2ndaqueous composition consists of water, preferably de-ionised water, more preferably de-ionised and deoxygenated water.

7. The method of any one or more of claims 1 - 6 wherein a dilution, defined asViVois at least 1.01 , preferably at least 1.10, more preferably from from 1.01 to 5.00, preferably from 1.10 - 3.00, more preferably from 1 .30 - 2.50, wherein Vi corresponds to the volume of the diluted mixture andocorresponds to the volume of the mixture of catalyst beads and first aqueous composition.

8. The method of any one or more of claims 1 - 7 wherein the transferring in step b) is carried out by pouring the mixture contained in the first container through an opening of said first container into the second container, or by allowing the mixture in the first container to flow under gravity from an opening in said first container and into said second container.

9. The method of claim 8 wherein the second container is in fluid communication with a funnel and / or piping system receiving the mixture from the first container.

10. The method of any one or more of claims 1 - 9 wherein an outlet of the second container is located lower than an inlet of the reactor for receiving the diluted mixture comprising catalyst beads.11 . The method of any one or more of claims 1 - 10 wherein the second container has a volume of from 2 to 20 times the volume of the first container.

12. The method of any one or more of claims 1 - 10 wherein the reactor is a downflow reactor comprising a porous catalyst support layer which is substantially impermeable to the catalyst beads.

13. A system for carrying out the method in accordance with one or more of claims 1 - 12 comprising i) an unloading station equipped to receive the at least one first container, ii) at least one second container, iii) passive transferring means for transporting the mixture of said at least one first container into the at least one second container by pouring or by gravity,iv) dilution means for diluting the mixture of catalyst beads and first aqueous composition in said at least one second container or in said passive transferring means, v) one or more reactors, vi) means for transporting the diluted mixture in the at least one second container to said one or more reactors under low shear conditions.

14. A method for starting up a reactor for the manufacture of bisphenol, comprising i) adding to a reactor ion-exchange resin beads in accordance with the method of any one or more of claims 1 - 12 thereby forming a layer of catalyst beads inside said reactor, ii) washing the catalyst bed with water, iii) continuously reacting a ketone and a phenol in said reactor and catalysed by said ion-exchange resin catalyst so as to form a bisphenol.

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