TWI644894B - Process for the production of cyclohexanone from phenol - Google Patents

Abstract

An industrial scale continuous process for the production and recovery of cyclohexanone from phenol and hydrogen, the process comprising: hydrogenating the phenol in a phenol hydrogenation reactor; separating and purifying the fraction comprising at least 4 distillation sections [II The cyclohexanone is separated from the hydrogenated product stream; wherein at least some of the heat of reaction generated in the phenol hydrogenation reaction portion [I] is applied to the vapor production; and the ring in which the phenol hydrogenation reactor is charged The molar ratio of ketone to phenol is 0.02 to 0.10; and/or the molar ratio of cyclohexanol to phenol in which the phenol hydrogenation reactor is charged is 0.001 to 0.10.

Description

Method for producing cyclohexanone from phenol Field of invention

The present invention relates to a continuous process for the preparation of cyclohexanone from phenols on an industrial scale; and to a chemical plant suitable for carrying out the process according to the invention on an industrial scale.

Background of the invention

The vast majority of cyclohexanone is consumed in the production of caprolactam, which is an intermediate in the manufacture of nylon 6. A mixture of cyclohexanone and cyclohexanol has been used to produce adipic acid, which is primarily converted to nylon 6,6. Further, cyclohexanone can be used as an industrial solvent or as an activator in an oxidation reaction. It can also be used as an intermediate in the production of cyclohexanone resin.

In the 1930s, cyclohexanone was produced on an industrial scale at the same time as the commercial production of caprolactam and nylon 6. Since the production volume of cyclohexanone has grown, the current annual production of cyclohexanone has exceeded 6 million tons.

Industrial scale means a production rate of at least 1,000 kg of cyclohexanone per hour, more preferably at least 5,000 kg of cyclohexanone per hour and most preferably at least 10,000 kg of cyclohexanone per hour.

Conventionally, cyclohexanone is prepared from a phenol by catalytic hydrogenation in a phenol hydrogenation reactor by, for example, using a platinum or palladium catalyst. The reaction can be carried out in the liquid phase or in the gas phase. [Kirk-Othmer Encyclopedia of Chemical Technology , ^{e.g., 3 rd Edition, Vol.7 (1979} ) p.410-416; I.Dodgson et al., "A low Cost Phenol to Cyclohexanone Process ", Chemistry & Industry, 18, December 1989 , p.830-833; or MT.Musser "Cyclohexanol and Cyclohexanone", Ullmann 's Encyclopedia of Industry Chemistry (7 th Edition, 2007), ( hereinafter referred to as "Musser")].

A method for hydrogenating phenols into two main products, cyclohexanone and cyclohexanol, can be described by the following stoichiometric equation: and

In the conventional methods, it is usually necessary to obtain the desired product yield (the formed cyclohexanone and/or cyclohexanol, such as the percentage of the phenol feed), and the selectivity of the reaction (formed cyclohexanone formed). And / or cyclohexanol, such as the percentage of phenol that has been converted) to compromise. As described in the above-identified bulletin, several factors play a role here, including temperature, catalyst selection, and hydrogen/phenol feed ratio.

A conventional method for the preparation and recovery of cyclohexanone from phenolic starting materials is described in Musser or in US 3,305,586. This method consists of two or two selective parts. The cyclohexanone system is prepared in the phenol hydrogenation reaction section. In the phenol hydrogenation reaction section, a gas phase process or a liquid phase process is used to hydrogenate the fresh phenol stream. From the phenol hydrogenation reaction portion, a hydrogen-containing one is selected and selected A purge stream of a neutral such as nitrogen and/or methane, and a phenol hydrogenation reaction product stream comprising cyclohexanone and cyclohexanol, phenol and side products. In the separated and purified fraction, cyclohexanone is separated from the phenol hydrogenation reaction portion product stream. The co-produced cyclohexanol is selectively converted to cyclohexanone in the cyclohexanol dehydrogenation reaction portion.

The method for dehydrogenation of cyclohexanol to cyclohexanone can be described by the following stoichiometric equation:

Generally, this endothermic dehydrogenation reaction is carried out in the gas phase. Several catalysts can be applied to this dehydrogenation reaction, including copper and/or zinc based catalysts, including catalysts comprising CuCrO ₄ 2CuO.2H ₂ O, CuMgO, CuZnO, CuCrO, CuCrMnV, and ZnO.

The cyclohexanone is typically recovered by distillation, such as a cyclohexanone-rich product (usually very rich 90% by weight) or as a substantially pure product ( 99% by weight). For the manufacture of high grade nylon, it is desirable to have a purity of at least 99.5% by weight and more preferably at least 99.8% by weight of cyclohexanone.

In 2008, Alexandre C. Dimian and Costin Sorin Bildea (Chapter 5: "Phenol Hydrogenation to Cyclohexanone" in "Chemical Process Design: Computer-Aided Case Studies", 2008, Wiley-VCH Verlag GmbH & Co. KGA, Weinheim, ISBN : 978-3-527-31403-4) It is reported that the overall vapor consumption of the phenol hydrogenation reaction portion and the separated and purified portion is 1.40 kg of vapor per kg of product. In addition, the cyclohexanol dehydrogenation reaction requires a high temperature of 0.49 million joules per kilogram of product (4.1 kg of product per second). Said that 2010 is hot.) In this case, the product was cyclohexanone having a purity of 98 mol%.

Therefore, in this case, the production of cyclohexanone from phenol requires 1.40 kg of steam per kg of product plus 0.49 million joules of heat per kg of product.

The net energy consumption of the method can be calculated from these quantities after converting the amount of vapor consumption presented to the amount of energy consumed. A. C. Dimian et al., on page 158 (line 9), provides a enthalpy of evaporation of water to steam of 2.083 million joules per kilogram of vapor. By using this value, the net energy consumption of the process can be expressed as about 3.4 million joules per kilogram of product (=1.40*2.083+0.49).

The net vapor consumption of the process can also be calculated in the event that the 0.49 million Joules of heat per kilogram of product required by the process is supplied by steam heating. The net vapor consumption of the process is then about 1.6 kg (= 1.40 + 0.49 / 2.083) vapor per kg of product. It should be noted that the energy integration study conducted by A. C. Dimian et al. is based on a flow chart for liquid separation by an indirect procedure for the distillation of the phenol azeotrope without overhead.

A problem with the prior art is that the net energy consumption per kilogram of product from the production of pure cyclohexanone from phenol is high and can easily be greater than 3 million joules per kilogram of product. And in the event that all of the heat is supplied by steam, the net vapor consumption can easily be greater than 1.5 kilograms of vapor per kilogram of product. The high net heat consumption per kilogram of product and/or the high net consumption of steam per kilogram of product not only has a negative impact on the carbon footprint of the process, but also has a negative impact on the variable cost of cyclohexanone production. An additional problem with the prior art is that the product obtained has only a purity of 98 mol%, which is almost equal to 98 wt%, since cyclohexanol is in the product. The main impurities. Additional purification of the product obtained to a product having a purity of 99.5 wt% or even 99.95% by weight will even further increase the net heat of consumption per kg of product and/or the net consumption vapor per kg of product.

Summary of invention

Accordingly, it is an object of the present invention to provide a process for the preparation of pure cyclohexanone on an industrial scale that has overcome or at least mitigates the above disadvantages.

Accordingly, it is an object of the present invention to provide a process for the preparation of pure cyclohexanone having a purity of at least 99.5% by weight which has a net energy consumption per kg of product lower than that known. The cyclohexanone produced by this method will have an improved carbon footprint and the variable cost of the manufactured cyclohexanone will be reduced. In addition, the cyclohexanone produced meets the specifications required for the production of high-grade nylon.

The present invention addresses the aforementioned disadvantages in that the method of converting at least 98% (mole/mole) of the supplied fresh phenolic product into a product (cyclohexanone) combines reducing the net energy per kilogram of product The net vapor consumption of consumption and/or per kg of product has an increased purity with the product produced. Preferably, even more than 99% (mole/mole) of fresh phenol supplied is converted to product. Even more preferably, even more than 99.5% (mole/mole) of fresh phenol supplied is converted into a product.

The net energy consumption per kilogram of product is reduced by the following combination: I) high phenol conversion per pass in the phenol hydrogenation reaction section; II) high cyclohexanone in the reaction mixture leaving the phenol hydrogenation reaction section a ratio of p-cyclohexanol; III) in the phenol hydrogenation reaction portion, each pass has a height toward the ring The selectivity of pentanone; and IV) in the process for the production, recovery and purification of cyclohexanone, the degree of high heat integration, and the high selectivity in the dehydrogenation process for cyclohexanol. The purity of the product has been increased by performing a distillation section with increased purification efficiency.

Thus, in accordance with the present invention, there is provided a continuous process for the production and recovery of cyclohexanone from phenols and hydrogen on an industrial scale, the process comprising: I) in a phenol hydrogenation reaction section [I], in a phenol hydrogenation reactor, The gas is hydrogenated to hydrogenate the phenol in the presence of a catalyst comprising platinum and/or palladium, thereby generating heat of reaction and discharging the hydrogenated product stream therefrom; II) in the separation and purification section [II], by inclusion The following multiple steps separate cyclohexanone from the hydrogenated product stream: i. in the first distillation section, remove components having a lower boiling point than cyclohexanone; ii. in the second distillation section, remove the ring Hexone; iii. in the third distillation section, removing the cyclohexanol-rich phase; and iv. in the fourth distillation section, removing the mixture comprising phenol and cyclohexanol; wherein the cyclohexanone has a cyclohexane An alcohol content of less than 5000 ppm (weight/weight); wherein at least some of the heat of reaction generated in the phenol hydrogenation reaction portion [I] is applied to the production of steam; and the phenol and the phenol which will be removed in the step iv) a mixture of cyclohexanol is charged into the phenol hydrogenation reaction portion [I]; characterized by application conditions a) Or at least one of b): a. molar ratio of cyclohexanone to phenol charged to the phenol hydrogenation reactor 0.02 to 0.10; b. The molar ratio of cyclohexanol to phenol charged into the phenol hydrogenation reactor is 0.001 to 0.10.

Preferably, the molar ratio of cyclohexanone to phenol charged to the phenol hydrogenation reactor is 0.02 to 0.08; more preferably 0.03 to 0.07; and still more preferably 0.03 to 0.05; for example, about 0.04.

Preferably, the molar ratio of cyclohexanol to phenol charged to the phenol hydrogenation reactor is from 0.002 to 0.05; more preferably from 0.003 to 0.04; for example, about 0.01.

Preferably, the molar ratio of cyclohexanone to phenol charged to the phenol hydrogenation reactor is 0.02 to 0.10, and the molar ratio of cyclohexanol to phenol charged to the phenol hydrogenation reactor is 0.001 to 0.10.

Preferably, the method further comprises dehydrogenating cyclohexanol to cyclohexanone and hydrogen in the cyclohexanol dehydrogenation reaction portion [III]. It is preferred that hydrogen generated in the cyclohexanol dehydrogenation reaction portion [III] is charged into the phenol hydrogenation reaction portion [I].

Preferably, the molar ratio of cyclohexanone to cyclohexanol in the hydrogenated product stream withdrawn in step I) is greater than 10. More preferably, the molar ratio of cyclohexanone to cyclohexanol in the hydrogenated product stream withdrawn in step I) is greater than 20; more preferably greater than 40; most preferably greater than 80. Preferably, the molar ratio of cyclohexanone to phenol in the hydrogenation product stream withdrawn in step I) is greater than 10. More preferably, the molar ratio of cyclohexanone to phenol in the hydrogenation product stream withdrawn in step I) is greater than 20; more preferably greater than 40; most preferably greater than 80.

In the process of the present invention, in step II), preferably, each of i, ii, ii and iv independently comprises the top of the column to remove the specifically specified product.

In step II), the process of the invention preferably comprises: i. in the first distillation section, the overhead of the component having a lower boiling point than cyclohexanone is removed. In step II), the process of the invention preferably comprises: ii. in the second distillation section, the top of the column removes cyclohexanone. In step II), the process of the invention preferably comprises: iii. In the third distillation section, the top of the column is enriched in a cyclohexanol-rich phase. In step II), the process of the invention preferably comprises: iv. In the fourth distillation section, the top of the column removes a mixture comprising phenol and cyclohexanol. Accordingly, it is preferred, according to the present invention, to provide a continuous process for the production and recovery of cyclohexanone from phenol and hydrogen on an industrial scale, the process comprising: I) in the phenol hydrogenation reaction portion [I], in phenol In a hydrogenation reactor, in the presence of a catalyst comprising platinum and/or palladium, gaseous hydrogen is used to hydrogenate the phenol, thereby generating heat of reaction and discharging the hydrogenated product stream therefrom; II) in the separation and purification section [II] The cyclohexanone is separated from the hydrogenated product stream by a plurality of steps comprising: i. in the first distillation section, the overhead removal component having a lower boiling point than cyclohexanone; ii. in the second In the distillation section, the top of the column removes cyclohexanone; iii. in the third distillation section, the top of the column removes the cyclohexanol-rich phase; and iv. In the fourth distillation section, the overhead removal comprises phenol and a ring a mixture of hexanol; wherein the cyclohexanone has a cyclohexanol content of less than 5000 ppm (weight/weight); wherein at least some of the heat of reaction generated in the phenol hydrogenation reaction portion [I] is applied to the production of steam; The mixture comprising phenol and cyclohexanol removed from the top of the column in step iv) Into the phenol hydrogenation reaction portion [I]; characterized by application of at least one of conditions a) or b): a. The molar ratio of cyclohexanone to phenol charged to the phenol hydrogenation reactor is 0.02 to 0.10; b. The molar ratio of cyclohexanol to phenol charged to the phenol hydrogenation reactor is 0.001 to 0.10.

The first distillation portion is followed by a second distillation portion followed by a third distillation portion followed by a fourth distillation portion. Preferably, the first distillation portion is directly followed by the second distillation portion directly following the third distillation portion, which is directly followed by the fourth distillation portion.

According to the present invention, cyclohexanone is defined as comprising less than 5000 ppm (w/w) cyclohexanol, more preferably less than 4000 ppm (w/w) cyclohexanol, when removed in the second distillation section. More preferably, it is less than 3000 ppm (w/w) cyclohexanol, further preferably less than 2000 ppm (w/w) cyclohexanol, and most preferably less than 1000 ppm (w/w) cyclohexanol. For the sake of clarity, 2000 ppm (w/w) cyclohexanol is 0.2% by weight of cyclohexanol.

The purity of cyclohexanone is defined as 100% minus the cyclohexanol content. Therefore, in this definition, impurities other than cyclohexanol are ignored.

The inclusion of 2000 ppm (w/w) cyclohexanol has a purity of 99.8% by weight of cyclohexanone and 0.2% by weight of cyclohexanol.

Preferably, the cyclohexanone produced has a purity of at least 99.8% by weight.

According to the present invention, it is preferred to be in the phenol hydrogenation reaction portion. Producing at least more than 30%, more preferably more than 40%, more preferably more than 50%, further preferably more than 65%, more preferably more than 80% and most preferably more 90% applied to the production of steam. The production of this vapor can be used in the methods of the invention or can be used in other applications. Preferably, the steam produced is used to transfer energy to drive one or more regeneration boilers in different distillation sections, or to the cyclohexanol dehydrogenation reaction section, or both.

The resulting hydrogenated product stream comprises phenol, hydrogen, inerts, and hydrogenated phenol.

Preferably, the phenol is hydrogenated in a gas phase process.

In the continuously operated phenol hydrogenation reaction section, the phenol conversion per pass is defined as (phenol ⁱⁿ -phenol ^out ) / phenol ⁱⁿ , wherein the phenol ⁱⁿ is charged into the phenol hydrogenation reaction portion of the phenol flow rate, which is in the molar / Seconds; and phenol ^out is the phenol flow rate from the phenol hydrogenation reaction portion, expressed in moles per second.

In the continuously operated phenol hydrogenation reaction portion, the selectivity per pass is defined as (cyclohexanone ^out -cyclohexanone ⁱⁿ ) / (phenol ⁱⁿ - phenol ^out ), whereby cyclohexanone ⁱⁿ is charged into the phenol The cyclohexanone flow rate of the hydrogenation reaction portion, expressed in moles per second; cyclohexanone ^out is the flow rate of cyclohexanone discharged from the phenol hydrogenation reaction portion, expressed in mol/sec; phenol ⁱⁿ is charged into the phenol The phenol flow rate of the hydrogenation reaction portion, expressed in moles per second; and the phenol ^out is the flow rate of the phenol discharged from the phenol hydrogenation reaction portion, expressed in moles per second.

Preferably, the selectivity per pass in the phenol hydrogenation reaction portion is greater than 90%. More preferably, it is greater than 91%, for example, greater than 92%, 93%, 94%, 95% or 96%.

Preferably, the phenol conversion system per pass in the phenol hydrogenation reaction portion is greater than 86%. More preferably, it is greater than 88%, for example, greater than 90%, 92%, 94%, 96%.

The cyclohexyl rich phase is defined as having a phase having a cyclohexanol content of more than 50% by weight, preferably more than 75% by weight and even more preferably more than 85% by weight.

The cyclohexanone-rich organic phase is defined as having a phase having a cyclohexanone content of more than 98% by weight, preferably more than 99% by weight and even more preferably more than 99.5% by weight.

Cyclohexanone has been economically produced with high phenol conversion, high product selectivity, high final product purity, and reduced net energy consumption.

In the phenol hydrogenation reaction portion, cyclohexanone and cyclohexanol are obtained in a continuous manner by catalytic hydrogenation of phenol. In principle, the hydrogenation catalyst applied can be any (supported) hydrogenation catalyst which catalyzes the hydrogenation of the phenol. Generally, the (supported) hydrogenation catalyst comprises one or more catalytically active metals and comprises a promoter. The (etc.) metal may in particular be selected from the group consisting of palladium, platinum, rhodium, ruthenium, osmium, iridium and osmium. Palladium, platinum or a combination thereof is preferably a catalytically active metal, in particular for the hydrogenation of phenols, in particular for hydrogenation to cyclohexanone or a mixture of cyclohexanone and cyclohexanol, wherein the cyclohexanone is the second The main components of the species. In principle, any suitable hydrogenation for use in the compound of interest can be used. The support is combined with the catalytic material it supports. In particular, suitable supports may be selected from the group consisting of alumina, activated carbon, titanium oxide, calcium carbonate and carbon black. Another support that can be used is cerium oxide. Supports selected from the group of alumina and activated carbon are particularly preferred for good stability and/or improved conversion of the support under the reaction conditions.

For the specific example in which the phenol to be hydrogenated is fed into the reactor as a vapor, it is particularly preferable to use alumina as a support.

For the specific example in which the phenol to be hydrogenated is fed into the reactor as a liquid, it is particularly preferable to use activated carbon as a support.

Preferably, the hydrogenation catalyst supported catalyst is applied comprising an accelerator comprising an alkali metal or alkaline earth metal salt. Preferably, the hydrogenation catalyst supported catalyst is applied, which comprises an alkali metal hydroxide, an alkaline earth metal hydroxide, an alkaline earth metal oxide, an alkali metal carbonate (hydrogen) salt and an alkaline earth. An accelerator for a group of metal carbonate (hydrogen) salts.

A promoter is added to increase the active life of the catalyst and selectivity to the desired product. Short life, ie, high deactivation rate means high process interruption frequency in order to recover or replace the catalyst, of course, reducing operating time and increasing cost. Lower selectivity means that more phenolic components are converted to products other than cyclohexanone.

A more preferred catalyst/support/accelerator combination is palladium on an alumina support. Optionally, Na in the form of NaHCO ₃ is added as a promoter.

Optimum catalyst / support / accelerator composition based on a 1 wt% palladium on alumina support, and 1 wt% of Na added (in the form of NaHCO ₃₎ as a promoter.

In the phenol hydrogenation reaction section, the hydrogenation reactor used may be any type of reactor suitable for hydrogenation of a compound to be hydrogenated, particularly any reactor suitable for hydrogenation of a phenol. For example, the reactor can be selected from the group consisting of a packed bed reactor, a slurry reactor, a shell-and-tube type heat exchange reactor having a catalyst in the tube and generating steam, and any other suitable reactor type. Most preferably, the hydrogenation according to the invention is carried out in a shell and tube type heat exchange reactor. Most preferably, in the shell and tube type heat exchange reactor, the tubes are filled with a supporting catalyst. Most preferably, the shell-and-tube type heat exchange reactor feeds water, for example, boiler feed water or condensate, to a volume that exceeds the range of the tubes to remove heat of reaction, thereby generating vapor. Optionally, the vapor produced is used for heating purposes.

The separation and purification section typically contains some distillation section. As used herein, the distillation section is a set comprising one distillation column or a plurality of parallel distillation columns, each having the same functionality, some of which may be vacuum distillation columns. Again, this section may include other typical distillation unit components, such as regenerative boilers and condensers.

The net energy consumption of the process is expressed in millions of joules per kilogram of cyclohexanone produced, which is defined as the sum of the energy consumed by the energy consumer minus the sum of the energy produced by the energy producer. The energy consumer is defined as a process step in which heat from outside the process step is charged to the process step via one or more heat exchangers. The energy generator is defined as a process step in which heat from the process step is discharged from the process step via one or more heat exchangers.

The net steam consumption is steamed per kilogram of cyclohexanone produced. The kilogram of gas is expressed as the sum of the vapors consumed by the vapor consumers minus the sum of the vapors produced by the steam generator. A vapor consumer is defined as a process step in which steam from outside the process step is charged via the one or more heat exchangers into the process step. A vapor generator is defined as a process step in which vapor from the process step is discharged from the process step via one or more heat exchangers.

Preferably, in the present invention, in order to achieve a purity of 99.5 wt% of cyclohexanone, the net energy consumption expressed in millions of joules per kilogram of cyclohexanone produced is less than 3 million joules/kg. The cyclohexanone produced. More preferably, it is less than 2.5 million joules per kilogram of cyclohexanone produced, such as less than 2 million joules per kilogram or less than 1.7 million joules per kilogram.

Preferably, in the present invention, in order to achieve a purity of 99.5 wt% of cyclohexanone, the net vapor consumption expressed in kilograms of steam per kilogram of cyclohexanone produced is less per cyclohexanone produced per kilogram. At 1.5 kg of steam. More preferably, it produces less than 1.0 kg of vapor per kilogram of cyclohexanone, for example less than 0.8 kg of vapor per kilogram.

The net energy consumption of the process can also be expressed in kilograms of steam per cyclohexanone produced. As for the conversion factor, an (average) enthalpy of evaporation of water to vapor should be used in millions of joules per kilogram of vapor, as is known to those skilled in the art.

In a further embodiment of the invention, there is provided a continuous chemical plant for the production and recovery of cyclohexanone from phenol and hydrogen on an industrial scale, the plant comprising: I) a phenolic hydrogenation reaction moiety [I] comprising a phenol Hydrogenation reactor, wherein The phenol is hydrogenated using gaseous hydrogen in the presence of a platinum-containing and/or palladium catalyst, thereby generating heat of reaction and discharging the hydrogenated product stream therefrom; II) separating and purifying the fraction [II], borrowing from here The cyclohexanone is separated from the hydrogenated product stream by a plurality of steps comprising: i. a first distillation section where the component having a lower boiling point than cyclohexanone is removed; ii. a second distillation section, a cyclohexanone; iii. a third distillation section, wherein the cyclohexanol-rich phase is removed; and iv. a fourth distillation section, wherein the mixture comprising phenol and cyclohexanol is removed; wherein the cyclohexanone has The cyclohexanol content is less than 5000 ppm (weight/weight); wherein at least some of the heat of reaction generated in the phenol hydrogenation reaction portion [I] is applied to the production of steam; and the removal thereof in the step iv) a mixture comprising phenol and cyclohexanol is charged to the phenol hydrogenation reaction portion [I]; characterized by applying at least one of conditions a) or b): a. cyclohexanone charged to the phenol hydrogenation reactor The ear ratio is 0.02 to 0.10; b. The molar ratio of cyclohexanol to phenol charged to the phenol hydrogenation reactor is 0.001 to 0.10.

Typically, the phenol hydrogenation reaction portion [I] comprises: a vapor-heated heat exchanger portion [a] for heating a fresh phenol feed; - a vapor-heated evaporation portion [b] for evaporating the phenol; a steam heated heat exchanger portion [c] for heating a fresh hydrogen feed; a hydrogen purification unit [d] for purifying a fresh hydrogen feed by catalytically converting CO and removing H2S by an adsorbent; - a vapor-heated heat exchanger portion [e] for heating the evaporated phenol And a hydrogen feed; a phenol hydrogenation moiety [f] for gas phase hydrogenation of phenol and steam from cooling water; a heat exchanger portion [g] for transferring heat from the phenol hydrogenation product stream to hydrogen Recirculating feed; - heat exchanger portion [h] for recovering heat from the phenol hydrogenation product stream; - water cooled heat exchanger portion [i] for cooling the phenol hydrogenation product stream; - gas-liquid separation a portion [j] for separating hydrogen from the phenol hydrogenation product stream; a compression portion [k] for compressing the separated hydrogen; and a (selective) heat exchanger portion [m] for cooling The compressed hydrogen.

Preferably, the phenol hydrogenation moiety [1] comprises one or more shell-and-tube type hydrogenation reactors for phenol hydrogenation in the gas phase, wherein in two or more cases, the parallel operation and the use of water are used A coolant in which water evaporates to form a vapor.

Preferably, the heat exchanger portion [h] is used to recover heat from the phenol hydrogenation product stream and transfer it to the cyclohexanol dehydrogenation portion.

I‧‧‧Phenol hydrogenation reaction

II‧‧‧Isolation and purification section

III‧‧‧Cyclohexanol dehydrogenation reaction

A-H, J-L, 1-69‧‧‧ catheter

a, c, e, α‧‧‧ steam heated heat exchanger section

B‧‧‧ evaporation part of steam heating

D‧‧‧ Hydrogen purification unit

F‧‧‧ Phenol hydrogenation

g,h,m,z,β‧‧‧heat exchanger section

i, ε‧‧‧ water cooled heat exchanger section

j, λ‧‧‧ gas-liquid separation section

k‧‧‧Compressed part

n, y‧‧‧ intermediate storage part

o‧‧‧First distillation section

p, r, t, v, x‧‧‧ condensation

q‧‧‧Second distillation section

S‧‧‧third distillation section

U‧‧‧fourth distillation section

W‧‧‧ fifth distillation section

Δ‧‧‧ cyclohexanol dehydrogenation reactor section

Figure 1 schematically illustrates a process for the preparation and recovery of cyclohexanone from phenols in accordance with the present invention.

Fig. 2 schematically illustrates a specific example of the phenol hydrogenation reaction portion [I] according to the present invention.

Figure 3 schematically illustrates a specific example of the isolated and purified fraction [II] according to the present invention.

Fig. 4 schematically illustrates a specific example of the cyclohexanol dehydrogenation reaction portion [III] according to the present invention.

Detailed description of the preferred embodiment

Figure 1 schematically shows a method for preparing and recovering cyclohexanone from phenol. This method usually consists of two parts selectively having a third part. All three parts have been shown.

A cyclohexanone system is prepared in the phenol hydrogenation reaction portion [I].

The cyclohexanone system is recovered in the isolated and purified fraction [II].

In the selective cyclohexanol dehydrogenation reaction portion [III], cyclohexanol is catalytically converted into cyclohexanone and hydrogen.

This phenol hydrogenation reaction section [I] particularly comprises a hydrogenation reactor which supplies a hydrogen stream via a conduit [A] during use, a fresh phenol stream via a conduit [B] and a recycled phenol via a conduit [E] Stream) and can include additional equipment. See, for example, Figure 1 in Musser or in US 3,305,586. The hydrogenation can take place in a gas phase process or in a liquid phase process. A purge gas stream comprising hydrogen and a selective inert such as nitrogen and/or methane is discharged from the phenol hydrogenation reaction portion [I] via a conduit [C]; and a cyclohexanone, a phenol and a side product are discharged via the conduit [D]. A partial product stream of a phenol hydrogenation reaction such as cyclohexanol. The phenol hydrogenation reaction portion product stream is supplied to the separation and purification portion [II] via a conduit [D].

In the isolated and purified fraction [II], cyclohexanone is usually recovered, Phenols and side products such as cyclohexanol. Optionally, a cyclohexanol dehydrogenation reaction portion [III] product comprising cyclohexanol and cyclohexanone is supplied to the separation and purification portion [II] via a conduit [K] for further recovery of cyclohexanone and Side product, such as cyclohexanol.

A stream comprising recycled phenol is withdrawn from the separation and purification section [II] via conduit [E]; a light component stream comprising benzene, cyclohexane and water is selectively discharged via conduit [F]; via conduit [G] The cyclohexanone stream is discharged; a heavy component stream comprising phenol and higher boiling components is discharged via conduit [H]; and a cyclohexanol-containing stream is discharged via conduit [J]. Alternatively, the cyclohexanol-containing stream is supplied to the cyclohexanol dehydrogenation reaction portion [III] via a conduit [J]. Optionally, the cyclohexanol-containing stream is withdrawn from the process for the preparation and recovery of cyclohexanone from the phenolic feed and used or supplied to another process in this manner (not shown in Figure 1).

The cyclohexanol dehydrogenation reaction portion [III] usually comprises a dehydrogenation reactor and one or more heat exchangers. In the cyclohexanol dehydrogenation reaction portion, cyclohexanol is catalytically converted into cyclohexanone and hydrogen. In general, the dehydrogenation of cyclohexanol is a gas phase reaction which is carried out at a temperature above 200 °C. Optionally, the cyclohexanol dehydrogenation reaction product stream comprising cyclohexanol and cyclohexanone is supplied to the isolated and purified fraction [II] via conduit [K]. Hydrogen generated in the cyclohexanol dehydrogenation reaction portion [III] is discharged via the conduit [L]. Alternatively, hydrogen generated in the cyclohexanol dehydrogenation reaction portion [III] is supplied to the phenol hydrogenation reaction portion [I] (not shown in Fig. 1). Alternatively, the hydrogen produced in the cyclohexanol dehydrogenation reaction portion [III] is supplied to another hydrogen consumption method (not shown in Fig. 1). Alternatively, hydrogen generated in the cyclohexanol dehydrogenation reaction portion [III] is supplied to the heat generating unit (not shown in Fig. 1).

An illustration of a specific example of the phenol hydrogenation reaction portion [I] according to the present invention is provided in FIG.

A fresh phenol stream is charged via conduit [1] and a stream containing recycled phenol is charged via conduit [2], thus forming a combined stream flowing through conduit [3]. The stream containing recycled phenol discharged from the separation and purification section [II] is charged via a conduit [2] (catheter [E] in Fig. 1; conduit [2] in Fig. 3). The combined flow flowing through the conduit [3] is heated in the heat exchanger portion [a], and the heated flow obtained through the conduit [4] is discharged and charged into the evaporation portion [b]. The heat exchanger portion [a] comprises one or more heat exchangers operating in parallel and/or in series. Selectively, lack or bypass the heat exchanger [a] (not shown in Figure 2).

Fresh hydrogen gas was charged into the phenol hydrogenation reaction portion [I] via a conduit [5]. Typically, the fresh hydrogen is derived from a petroleum grease cracker, a methane recombiner or an electrolysis process. Generally, the fresh hydrogen includes inert components such as nitrogen and/or methane. In the case where the fresh hydrogen includes harmful components such as CO and/or H ₂ S, a hydrogen purification step is required. These harmful components present in the fresh hydrogen may be of a temporary type, for example due to abnormal conditions in a fresh hydrogen production unit; or may be permanent. In this hydrogen purification step, the deleterious impurities can be converted to or removed from the inert hydrogen stream.

Fresh hydrogen is charged into the heat exchanger portion [c] via the conduit [5]. In the heat exchanger portion [c], the temperature of the fresh hydrogen gas is modified to the temperature required in the hydrogen purification unit [d]. Generally, in the heat exchanger portion [c], the temperature of the fresh hydrogen gas is increased. The temperature-modified fresh hydrogen gas is discharged from the heat exchanger portion [c] via a conduit [6] and charged into a hydrogen purification portion [d]. The heat exchanger portion [c] comprises one or more heat exchangers operating in parallel and/or in series. Selectively, lack or bypass the heat exchanger portion [c] (not shown in Figure 2). The hydrogen purification portion [d] may contain one or more catalysts for converting harmful components into inert components and/or one or more adsorbents for removing harmful components. Generally, the hydrogen purification portion [d] comprises a catalyst for converting CO and/or an adsorbent for removing H ₂ S. Hydrogen is discharged from the hydrogen purification portion [d] via a conduit [7]. The hydrogen gas combined in the conduit [7] and the recycled hydrogen gas in the conduit [23] thus form a flow flowing through the conduit [8], which is charged into the evaporation portion [b]. The hydrogen purification section [d] comprises one or more reaction and/or adsorption units operating in parallel and/or in series. Selectively, lack or bypass the hydrogenated moiety [d] (not shown in Figure 2).

In this evaporation portion [b], virtually all of the components input via the conduit [4] and via the conduit [8] are evaporated. A gas component stream is discharged from the evaporation portion [b] via a conduit [10]. A small amount of components input via the conduit [4] and via the conduit [8] are not evaporated, and are discharged (continuous or batch) from the evaporation portion [b] via the conduit [9]. Generally, the evaporated portion [b] is heated by steam. Generally, the evaporation portion [b] includes a means for removing droplets entrained by the flow of the discharged gaseous components, for example, a wire mesh demister. The evaporation portion [b] comprises one or more evaporators operating in parallel and/or in series. Selectively, the temperature of the gas component stream in the conduit [10] is adjusted in the heat exchanger portion [e]. Generally, the temperature of the gas component stream is increased in the heat exchanger portion [e]. The temperature-regulated stream is discharged to the heat exchanger portion [e] via a conduit [11]. The heat exchanger portion [e] comprises one or more heat exchangers operating in parallel and/or in series. Selectively, some of the vapor form, eg via a conduit [12] The water is added to the stream in the conduit [11], thus forming a stream flowing through the conduit [13], which is charged into the phenol hydrogenation portion [f]. The phenol hydrogenation moiety [f] consists of one or more hydrogenation reactors operated in series and/or in parallel. In the phenol hydrogenation portion [f], cyclohexanone and cyclohexanol are obtained in a continuous manner by catalytic hydrogenation of a phenol.

For the sake of clarity, the phenol hydrogenation moiety [f] is part of the phenol hydrogenation reaction moiety [I].

A gas mixture comprising hydrogen, phenol, cyclohexanone and cyclohexanol is discharged from the phenol hydrogenation moiety [f] via a conduit [14]. In the heat exchanger portion [g], this gas mixture is subjected to heat exchange with a gas mixture containing hydrogen which is charged into the heat exchanger portion [g] via a conduit [22]. In the heat exchanger portion [g], the gas mixture charged through the conduit [14] is cooled while heating the gas mixture containing hydrogen charged through the conduit [22]. The cooled gas mixture containing hydrogen, phenol, cyclohexanone and cyclohexanol is discharged to the heat exchanger portion [g] via a conduit [15]. The heat exchanger portion [g] comprises one or more heat exchangers operating in parallel and/or in series. Selective, lacking or bypassing the heat exchanger portion [g] (not shown in Figure 2). Transporting the cooled gas mixture comprising hydrogen, phenol, cyclohexanone and cyclohexanol via a conduit [15] and charging it into the heat exchanger portion [h], where it is further cooled and thereby selectively condensed out Monophenol, cyclohexanone and cyclohexanol fractions. Alternatively, a process stream from the separated and purified fraction [II] or from the cyclohexanol dehydrogenation reaction portion [III] is used as a coolant (not shown in Fig. 2). Preferably, the process stream fed to the first distillation section in the separation and purification section [II] is used as a coolant, thereby heating the stream (not shown in Fig. 2). The heat exchanger part [h] package Containing one or more heat exchangers operating in parallel and/or in series. Selectively, lack or bypass the heat exchanger portion [h] (not shown in Figure 2).

The mixture comprising hydrogen, phenol, cyclohexanone and cyclohexanol is further cooled via a conduit [16] and charged into the heat exchanger portion [i], where it is further cooled, whereby the heat exchange is carried out At least one of a phenol, a cyclohexanone, and a cyclohexanol fraction is condensed in the portion [i]. The heat exchanger portion [i] comprises one or more heat exchangers operating in parallel and/or in series. A mixture containing hydrogen and liquid phenol, cyclohexanone, and cyclohexanol is discharged from the heat exchanger portion [i] via a conduit [17], and charged into the gas-liquid separation portion [j]. The gas-liquid separation section [j] comprises one or more gas-liquid separators operating in parallel and/or in series. A liquid mixture containing phenol, cyclohexanone and cyclohexanol is discharged from the gas-liquid separation portion [j] via a conduit [18], and charged into the separated and purified portion [II] shown in Fig. 3. A gas mixture containing hydrogen is discharged from the gas-liquid separation portion [j] via a conduit [19], and charged into the compressed portion [k]. The compressed portion [k] comprises one or more devices operating in parallel and/or in series to compress a gas mixture. The compressed gas mixture is discharged through the conduit [20] to the compressed portion [k]. Generally, the gas-liquid separation portion [j] includes a means for removing droplets entrained by the discharged gas component stream, for example, a wire mesh demister. The compressed gas mixture exiting via conduit [20] is divided into a compressed gas mixture transported via conduit [21] and a compressed gas mixture transported via conduit [22]. The compressed gas mixture transported via conduit [22] is charged to the heat exchanger portion [g] where it is heated. Selective, lacking or bypassing the heat exchanger portion [g] (not shown in Figure 2). Discharging the heated via conduit [23] The gas mixture, the recycled hydrogen, is then combined with the hydrogen in the conduit [7].

The compressed gas mixture transported via conduit [21] is charged to heat exchanger portion [m] where the compressed gas mixture is cooled. The liquid formed in the heat exchanger portion [m] is discharged through the conduit [25], and charged into the gas-liquid separation portion [j]. The cooled gas mixture obtained in the heat exchanger portion [m] is discharged via a conduit [24]. Generally, the gas mixture exiting via conduit [24] contains hydrogen and one or more inert components such as nitrogen and/or methane. Alternatively, the gas mixture exiting via conduit [24] is used as a fuel.

An illustration of a specific example of the isolated and purified fraction [II] according to the present invention is provided in FIG.

The liquid mixture comprising phenol, cyclohexanone and cyclohexanol discharged from the phenol hydrogenation reaction portion [I] via the conduit [18] (Fig. 2) can be selectively reacted with the dehydrogenation reaction portion from the cyclohexanol [III] via a conduit [26] The discharged liquid mixture containing cyclohexanone and cyclohexanol (Fig. 4) is combined, thereby forming a stream flowing through the conduit [27], which is charged into the intermediate storage portion [n].

The intermediate storage portion [n] comprises one or more storage devices, such as vessels, reservoirs, containers. Selective, lacking or bypassing the intermediate storage portion [n] (not shown in Figure 3). A liquid mixture containing phenol, cyclohexanone, and cyclohexanol discharged from the intermediate storage portion [n] via a conduit [28] is charged into the heat exchanger portion [h], where it is heated. In the heat exchanger portion [h], the cooled gas mixture (see Fig. 2) containing hydrogen, phenol, cyclohexanone and cyclohexanol transported via the conduit [15] acts as a heating medium. Will be hot from The heated stream discharged from the converter portion [h] is charged into the first distillation portion [o] via the conduit [29]. The heat exchanger portion [h] comprises one or more heat exchangers operating in parallel and/or in series. Selective, lacking or bypassing the heat exchanger portion [h] (not shown in Figure 3). Alternatively, the liquid mixture transported via conduit [29] is heated in another heat exchanger portion (not shown in Figure 3) before being charged to the first distillation portion [o].

In the first distillation section [o], light components such as benzene and water are removed from the feed charged via the conduit [29], but are discharged from the first distillation section [o] via a conduit [36] A mixture comprising cyclohexanone, phenol and cyclohexanol and a heavy component is, for example, a bottom fraction, and is charged into the second distillation portion [q]. The first distillation section [o] comprises one or more distillation columns operating in series or in parallel. Preferably, the first distillation portion [o] is operated at a pressure of less than 0.2 MPa. Preferably, the distillation column in the first distillation section [o] is equipped with a tray and/or a filling, more preferably a tray. The distillation column is equipped with one or more regeneration boilers. Preferably, the regeneration boiler is steam driven.

The top vapor is discharged from the first distillation portion [o] via the conduit [30] and condensed in the condensed portion [p]. In the condensed portion [p], three phases are obtained: a gas phase containing hydrogen, which is discharged via a conduit [31]; an aqueous phase, which is discharged via a conduit [32]; and an organic phase, which is discharged via a conduit [33]. Optionally, the gas phase containing hydrogen gas discharged through the conduit [31] is sent to an incinerator (not shown in Figure 3). Optionally, the aqueous phase exiting via conduit [32] is sent to a wastewater treatment system (not shown in Figure 3). The organic phase discharged via the conduit [33] is separated, and a portion is charged into the first distillation portion [o] via a conduit [34] such as reflux, and another portion is discharged via a conduit [35] as a light component. select The light components discharged through the conduit [35] were filled into a buffer tank (not shown in Figure 3). Optionally, the light components discharged via conduit [35] are sent to an incinerator (not shown in Figure 3). The condensing portion [p] comprises one or more condensers operating in series or in parallel. Optionally, the condensing portion [p] comprises a separating liquid/liquid separator for separating the aqueous phase discharged via the conduit [32] and the organic phase discharged via the conduit [33].

In the second distillation portion [q], the cyclohexanone is removed from the feed charged via the conduit [36], but the phenol and the ring are discharged from the second distillation portion [q] via the conduit [42]. A mixture of hexanol and a heavy component is, for example, a bottom fraction, and is charged into the third distillation portion [s]. The second distillation section [q] comprises one or more distillation columns operating in series or in parallel. Preferably, the second distillation portion [q] is operated at a pressure of less than 0.1 MPa. Preferably, the distillation column in the second distillation section [q] is equipped with a tray and/or a filling, more preferably a filling. The distillation column is equipped with one or more regeneration boilers. Preferably, the regeneration boiler is steam driven.

The top vapor is discharged from the second distillation portion [q] via the conduit [37] and condensed in the condensed portion [r]. In the coagulated portion [r], two phases are obtained: a gas phase containing nitrogen and cyclohexanone vapor discharged through a conduit [38], and a cyclohexanone-rich organic phase discharged via a conduit [39]. Optionally, the gas phase containing nitrogen and cyclohexanone vapor exiting via conduit [38] is sent to an incinerator (not shown in Figure 3). The cyclohexanone-rich organic phase discharged via the conduit [39] is separated, and a portion is charged into the second distillation portion [q] via the conduit [40] as reflux, and another portion is discharged via the conduit [41]. For the final product. In general, the final product discharged via conduit [41] is filled into the final product. Object slot (not shown in Figure 3). The condensing portion [q] contains one or more condensers that operate in series or in parallel. Alternatively, the coagulated portion [q] comprises a pump vessel from which the cyclohexanone-rich organic phase is withdrawn via conduit [39].

In the third distillation section [s], cyclohexanol is removed from the feed charged via the conduit [42], but the phenol and the ring are discharged from the third distillation section [s] via the conduit [48] A mixture of hexanol and a heavy component is, for example, a bottom fraction, and is charged into the fourth distillation portion [u]. The third distillation section [s] comprises one or more distillation columns operating in series or in parallel. Preferably, the third distillation portion [s] is operated at a pressure of less than 0.1 MPa. Preferably, the distillation column in the third distillation section [s] is equipped with a tray and/or a charge, more preferably a filler is used above the feed position. The distillation column is equipped with one or more regeneration boilers. Preferably, the regeneration boiler is steam driven.

The top vapor is discharged from the third distillation portion [s] via the conduit [43] and condensed in the condensed portion [t]. In the condensed portion [t], two phases are obtained: a gas phase containing nitrogen gas and cyclohexanol vapor discharged through a conduit [44], and a cyclohexanol-rich organic phase discharged via a conduit [45]. Optionally, the gas phase containing nitrogen and cyclohexanol vapor discharged via conduit [44] is sent to an incinerator (not shown in Figure 3). The cyclohexanol-rich organic phase discharged through the conduit [45] is separated, and a portion is charged into the third distillation portion [s] via a conduit [46] such as reflux, and another portion is discharged via a conduit [47]. The cyclohexanol-rich organic phase discharged through the conduit [47] was charged into the cyclohexanol dehydrogenation reaction portion [III] (Fig. 4). Optionally, some or all of the cyclohexanol-rich organic phase exiting via conduit [47] is discharged outside of the process for preparing and recovering cyclohexanone from phenol (not shown in Figure 3). The condensed portion [t] contains one or more Condenser operated in series or in parallel. Alternatively, the condensed portion [t] comprises a pump vessel from which the cyclohexanol-rich organic phase is discharged via a conduit [45].

In the fourth distillation section [u], cyclohexanol and phenol are removed from the feed charged via the conduit [48], but the phenol is discharged from the fourth distillation section [u] via the conduit [54] And the mixture of heavy components is, for example, a bottom fraction, and is charged into the selective fifth distillation section [w]. Alternatively, the mixture comprising phenol and heavy components discharged from the fourth distillation section [u], such as the bottom fraction, is discharged from the process via conduit [54] (not shown in Figure 3). Optionally, the mixture comprising phenol and heavy components discharged from the process via conduit [54] is charged to a buffer tank (not shown in Figure 3). Optionally, the mixture comprising phenol and heavy components discharged from the process via conduit [54] is sent to an incinerator (not shown in Figure 3).

The fourth distillation section [u] comprises one or more distillation columns operating in series or in parallel. Preferably, the fourth distillation section [u] is operated at a pressure of less than 0.1 MPa. Preferably, the distillation column in the fourth distillation section [u] is equipped with trays and/or fillers, more preferably having a charge above the feed location and a tray below the feed location. The distillation column is equipped with one or more regeneration boilers. Preferably, the regeneration boiler is steam driven.

The top vapor is discharged from the fourth distillation portion [u] via a conduit [49] and condensed in the condensed portion [v]. In the coagulated portion [v], two phases are obtained: a gas phase containing nitrogen gas and phenol vapor discharged through a conduit [50], and a phenol-rich and cyclohexanol phase discharged through a conduit [51]. Selectively, the gas phase containing nitrogen and phenol vapor discharged through the conduit [50] is sent to the incinerator (in FIG. 3 No display). The phenol-rich and cyclohexanol phases discharged via conduit [51] are separated, and a portion is charged into the fourth distillation portion [u] via conduit [52] as reflux, and another portion is discharged via conduit [53]. The phenol-rich and cyclohexanol phases discharged through the conduit [53] are charged into the phenol hydrogenation reaction portion [I]. Optionally, some or all of the phenol and cyclohexanol-rich phase exiting via conduit [53] is discharged outside of the process (not shown in Figure 3). The condensing portion [v] comprises one or more condensers operating in series or in parallel. Alternatively, the condensed portion [v] comprises a pump vessel from which the phenol- and cyclohexanol-rich organic phase is discharged via a conduit [51].

In the selective fifth distillation section [w], the phenol is removed from the feed charged via the conduit [54], whereas the phenol containing the phenol and recombined from the fifth distillation section [w] via the conduit [60] The fractionated mixture is, for example, the bottom fraction and is discharged from the process. Optionally, the mixture comprising phenol and heavy components discharged from the process via conduit [60] is charged to a buffer tank (not shown in Figure 3). Optionally, the mixture comprising phenol and heavy components discharged from the process via conduit [60] is sent to an incinerator (not shown in Figure 3).

The fifth distillation section [w] comprises one or more distillation columns operating in series or in parallel. Preferably, the fifth distillation portion [w] is operated at a pressure of less than 0.1 MPa. Preferably, the distillation column in the fifth distillation section [w] is equipped with trays and/or fillers, more preferably having a charge above the feed location and a tray below the feed location. The distillation column is equipped with one or more regeneration boilers. Preferably, the regeneration boiler is steam driven.

The top vapor is discharged from the fifth distillation portion [w] via the conduit [55] and condensed in the condensed portion [x]. In the condensed portion [x], two kinds are obtained Phase: a gas phase containing nitrogen and phenol vapor discharged via conduit [56], and a phenol-rich organic phase discharged via conduit [57]. Optionally, the gas phase containing nitrogen and phenol vapor discharged via conduit [56] is sent to an incinerator (not shown in Figure 3). The phenol-rich organic phase exiting via conduit [57] is separated, and a portion is charged into the fifth distillation portion [w] via conduit [58] as reflux, and another portion is discharged via conduit [59]. The phenol-rich organic phase discharged through the conduit [59] was charged into the phenol hydrogenation reaction portion [I] (Fig. 2). Optionally, some or all of the phenol-rich organic phase exiting via conduit [59] is discharged outside of the process (not shown in Figure 3). Combining the phenol-rich organic phase discharged via the conduit [59] with the phenol-rich and cyclohexanol-rich organic phase discharged via the conduit [53], and charging the phenol hydrogenation reaction portion via the conduit [2] [ I] (Figure 2). The condensing portion [x] comprises one or more condensers operating in series or in parallel. Alternatively, the coagulated portion [x] comprises a pump container from which the phenol-rich organic phase is discharged via a conduit [57].

An illustration of a specific example of the cyclohexanol dehydrogenation reaction portion [III] according to the present invention is provided in FIG.

The cyclohexanol-rich organic phase (see also FIG. 3) discharged from the separated and purified fraction [II] via a conduit [47] is charged into the intermediate storage portion [y]. The intermediate storage portion [y] comprises one or more storage devices, such as vessels, reservoirs, containers. Selectively, lack or bypass the intermediate storage portion [y] (not shown in Figure 4). The cyclohexanol-rich organic phase discharged from the intermediate storage portion [y] is charged into the heat exchanger portion [z] via a conduit [61], where it is heated. In the heat exchanger portion [z], the mixture containing hydrogen, cyclohexanone and cyclohexanol transported via the conduit [66] is acted as a heating medium. quality. The heated stream discharged from the heat exchanger portion [z] is charged into the heat exchanger portion [α] via a conduit [62]. The heat exchanger portion [z] comprises one or more heat exchangers operating in parallel and/or in series. Selectively, lack or bypass the heat exchanger portion [z] (not shown in Figure 4). In the heat exchanger portion [α], the heated stream discharged from the heat exchanger portion [z] via the conduit [62] is further heated, thereby obtaining a further heated stream, which is via a conduit [63]. ]discharge. The heat exchanger portion [α] comprises one or more heat exchangers operating in parallel and/or in series. Preferably, the heat exchanger portion [α] is heated by steam. Selective, lacking or bypassing the heat exchanger portion [α] (not shown in Figure 4). The further heated stream discharged from the heat exchanger portion [α] is charged into the heat exchanger portion [β] via a conduit [63], where it is even further heated. In the heat exchanger portion [β], the mixture containing hydrogen, cyclohexanone and cyclohexanol transported via the conduit [65] acts as a heating medium. The even further heated stream discharged from the heat exchanger portion [β] is charged into the cyclohexanol dehydrogenation reactor portion [δ] via a conduit [64]. The heat exchanger portion [β] comprises one or more heat exchangers operating in parallel and/or in series. Selectively, lack or bypass the heat exchanger portion [β] (not shown in Figure 4).

In the cyclohexanol dehydrogenation reactor portion [δ], a portion of the cyclohexanol system present in the even further heated stream charged via the conduit [64] is converted to cyclohexanone and hydrogen. Since this dehydrogenation reaction of cyclohexanol is endothermic, the cyclohexanol dehydrogenation reactor portion [δ] is heated. Generally, the heating of the cyclohexanol dehydrogenation reactor portion [δ] is carried out using a fuel gas, hot oil, liquid metal or steam as a heating medium. Preferably, steam or hot oil is used as a heating medium to complete the addition of the cyclohexanol dehydrogenation reactor portion [δ] It is better to use steam. The cyclohexanol dehydrogenation reactor portion [δ] comprises one or more dehydrogenation reactors operating in parallel and/or in series. In particular, the dehydrogenation reactor can be any type of reactor suitable for dehydrogenation of a compound to be dehydrogenated, particularly any reactor suitable for dehydrogenation of cyclohexanol. In particular, the reactor may be selected from the group consisting of a packed bed reactor, a slurry reactor, and a shell and tube type heat exchange reactor. Most preferably, the dehydrogenation according to the present invention is carried out in a shell-and-tube type heat exchange reactor having a dehydrogenation catalyst in the tube and a heating medium outside the tube. Most preferably, both the feed and the discharge of the cyclohexanol dehydrogenation reactor portion [δ] are in a gaseous state.

A mixture containing hydrogen, cyclohexanone, and cyclohexanol is discharged from the cyclohexanol dehydrogenation reactor portion [δ], and charged into the heat exchanger portion [β] via a conduit [65]. In the heat exchanger portion [β], the mixture comprising hydrogen, cyclohexanone and cyclohexanol is cooled, thereby obtaining a mixture comprising hydrogen, cyclohexanone and cyclohexanol which is discharged via the conduit [66] after cooling. . This cooled mixture comprising hydrogen, cyclohexanone and cyclohexanol is charged into the heat exchanger portion [z] via conduit [66]. In the heat exchanger portion [z], the cooled mixture comprising hydrogen, cyclohexanone and cyclohexanol is further cooled, thereby obtaining a further cooled mixture comprising hydrogen, cyclohexanone and cyclohexanol, It is discharged through a conduit [67]. This further cooled mixture comprising hydrogen, cyclohexanone and cyclohexanol is charged into the heat exchanger portion [ε] via a conduit [67]. In the heat exchanger portion [[epsilon]], the further cooled mixture comprising hydrogen, cyclohexanone and cyclohexanol is further cooled, thereby obtaining an even further cooled comprising hydrogen, cyclohexanone and cyclohexanol. The mixture is discharged via a conduit [68]. Preferably, this even further cooled comprises hydrogen, cyclohexanone and cyclohexyl The mixture of alcohols consists of a liquid phase comprising mainly cyclohexanone and cyclohexanol, and a gas phase comprising hydrogen. This even further cooled mixture comprising hydrogen, cyclohexanone and cyclohexanol is charged into the gas-liquid separation portion [λ] via a conduit [68]. The gas-liquid separation portion [λ] comprises one or more gas-liquid separators operating in parallel and/or in series. The liquid mixture mainly comprising cyclohexanone and cyclohexanol is discharged from the gas-liquid separation portion [λ] via a conduit [26], and charged into the separation and purification portion [II] (see also FIG. 3). . The hydrogen-containing gas mixture is discharged from the gas-liquid separation portion [λ] via a conduit [69]. Optionally, the hydrogen containing gas mixture exiting via conduit [69] is sent to an incinerator (not shown in Figure 4). Optionally, the hydrogen-containing gas mixture discharged via conduit [69] is sent to the phenol hydrogenation reaction portion [I] (not shown in Figure 4).

The present invention is illustrated by the following examples, but is not intended to be limiting: Example 1 describes a chemical plant for the preparation and recovery of cyclohexanone from phenol and phenol hydrogenation catalysts, wherein the catalyst has been used for a period of about 1 week.

Example 2 describes a chemical plant for the preparation and recovery of cyclohexanone from phenol and phenol hydrogenation catalysts, where the catalyst has been used for a period of about 9 months.

Example 1

An industrial-scale chemical plant for preparing and recovering cyclohexanone from a phenolic feedstock and having an hourly production capacity of about 12.5 tons of cyclohexanone per hour, operating in a continuous mode comprising: a monophenolic hydrogenation reaction portion [I ];- a separate and purified fraction [II]; and - a cyclohexanol dehydrogenation reaction moiety [III]; which is as previously described and has been used as depicted in Figures 1, 2, 3 and 4.

The phenol hydrogenation reaction portion [I] comprises: - a vapor-heated heat exchanger portion [a]; - a vapor-heated evaporation portion [b]; - a vapor-heated heat exchanger portion [c]; - a hydrogen purification unit [d] ], wherein the CO is catalytically converted and the H ₂ S is removed by the adsorbent; the vapor-heated heat exchanger portion [e]; the phenol hydrogenated portion [f], which comprises two gases in the gas phase a shell-and-tube type hydrogenation reactor in which phenol hydrogenation is carried out in parallel operation and using water as a coolant and water is evaporated to form a vapor; - heat exchanger portion [g]; - heat exchanger portion [h], wherein the heat system Exchange between the phenol hydrogenation reaction portion [I] and the separation and purification portion [II]; - water-cooled heat exchanger portion [i]; - gas-liquid separation portion [j]; - compression portion [k]; - Heat exchanger section [m]; and - Catheters [1] to [25] These are all in use during normal operation of the plant.

Fresh phenol is charged into the phenol hydrogenation reaction portion [I] via a conduit [1]. A gas mixture containing about 94% by volume of hydrogen and about 6% by volume of nitrogen was charged as fresh hydrogen into the phenol hydrogenation reaction portion [I] via a conduit [5]. Under normal operating conditions, the CO content of the fresh hydrogen and the H ₂ S content are each less than 1 ppm. The ratio of the amount of vapor added to the stream in the conduit [11] via the conduit [12] to the amount of fresh phenol is about 1% by weight. Pd/Al ₂ O ₃ (1% by weight) was added as a hydrogenation catalyst and 1% by weight of Na (in the form of NaHCO ₃ ) was applied as a promoter.

The isolated and purified fraction [II] comprises: - an intermediate storage portion [n]; - a heat exchanger portion [h], wherein the heat is between the phenol hydrogenation reaction portion [I] and the separation and purification portion [II] Exchange; - first distillation portion [o]; - coagulation portion [p]; - second distillation portion [q]; - coagulation portion [r]; - third distillation portion [s]; - coagulation portion [t]; - fourth distillation portion [u]; - coagulation portion [v]; - fifth distillation portion [w]; - coagulation portion [x]; and - conduit [2], [18] and [26] to [60] It is all in use during normal operation of the plant.

All of the distillation columns in the first distillation section [o], the second distillation section [q], the third distillation section [s], the fourth distillation section [u], and the fifth distillation section [w] are equipped with a vapor drive Regeneration boiler.

The cyclohexanol dehydrogenation reaction portion [III] comprises: - an intermediate storage portion [y]; - a heat exchanger portion [z]; a vapor heated heat exchanger portion [α]; - a heat exchanger portion [β] a cyclohexanol dehydrogenation reactor section [δ] comprising a shell and tube type reactor; a water-cooled heat exchanger section [ε]; a gas-liquid separation section [λ]; and a conduit [26] ], [47] and [61] to [69]; all in use during normal operation of the plant.

The heated medium vapor is applied to the cyclohexanol dehydrogenation reactor.

After the chemical plant for the preparation and recovery of cyclohexanone from phenol and fresh phenol hydrogenation catalyst was activated, the following results were obtained after about 1 week: - the final product cyclohexanone, which was discharged via conduit [41], with The cyclohexanol content is about 500 ppm (weight/weight) [99.95% by weight].

- The molar ratio of cyclohexanone to phenol charged to the phenol hydrogenation reactor is about 0.04.

- The molar ratio of cyclohexanol to phenol charged to the phenol hydrogenation reactor is about 0.005.

- The molar ratio of cyclohexanone to cyclohexanol in the hydrogenated product stream in conduit [14] is greater than 100.

- The molar ratio of the cyclohexanone to cyclohexanol is greater than 100 in the hydrogenated product stream withdrawn from the phenol hydrogenation reaction portion [I] via conduit [18].

- The molar ratio of cyclohexanone to phenol in the hydrogenated product stream in conduit [14] is greater than 100.

- The molar ratio of cyclohexanone to phenol in the hydrogenated product stream withdrawn from the phenol hydrogenation reaction portion [I] via conduit [18] is greater than 100.

- The molar component of the fresh phenolic material converted to cyclohexanone is greater than 99%.

The net energy consumption is about 0.7 million joules per kilogram of cyclohexanone produced, and the net vapor consumption is about 0.3 kilograms of vapor per kilogram of cyclohexanone produced. Thereby, the energy consumer is: - a steam-heated heat exchanger portion [a]; - a vapor-heated evaporation portion [b]; - a steam-heated heat exchanger portion [c]; - a steam-heated heat exchanger Part [e]; - steam heating of the first distillation portion [o], the second distillation column [q], the third distillation column [s], the fourth distillation column [u], and the fifth distillation column [w] Regeneration boiler; - steam heated heat exchanger portion [α]; and - steam heated cyclohexanol dehydrogenation reactor portion [δ]; and the energy generator system: - in the phenol hydrogenation portion [f] A shell-and-tube type hydrogenation reactor.

All of the energy consumers mentioned above are also steam consumers. All of the energy producers mentioned above are also steam generators.

Example 2

In the same chemical factory as described in Example 1, The preparation of the phenol and the recovery of cyclohexanone are carried out except that the phenol hydrogenation catalyst has been used for about 9 months instead of about 1 week. It is well known that the phenol hydrogenation catalyst exhibits aging behavior which causes selectivity and activity to decrease over time.

The following results are now obtained: - The final product cyclohexanone, which is discharged via conduit [41], has a cyclohexanol content of about 500 ppm (weight/weight).

- The molar ratio of cyclohexanone to phenol charged to the phenol hydrogenation reactor is about 0.04.

- The molar ratio of cyclohexanol to phenol charged to the phenol hydrogenation reactor is about 0.024.

- The molar ratio of cyclohexanone to cyclohexanol in the hydrogenated product stream in conduit [14] is about 12.

- The molar ratio of the cyclohexanone to cyclohexanol is about 12 in the hydrogenated product stream withdrawn from the phenol hydrogenation reaction portion [I] via conduit [18].

- The molar ratio of cyclohexanone to phenol in the hydrogenated product stream in conduit [14] is about 14.

- The molar ratio of the cyclohexanone to phenol in the hydrogenated product stream withdrawn from the phenol hydrogenation reaction portion [I] via conduit [18] is about 14.

- The molar component of the fresh phenolic material converted to cyclohexanone is greater than 99%.

- The net energy consumption is about 1.6 million joules per kilogram of cyclohexanone produced, and the net vapor consumption is about 0.7 kilograms of vapor per kilogram of cyclohexanone produced. Thereby, the energy consumer and the steam consumer, the energy generator and the steam generator are the same as those in the first embodiment.

In both of Example 1 and Example 2 - the selectivity per pass in the phenol hydrogenation reaction portion is more than 93%; and - the phenol conversion per pass in the phenol hydrogenation reaction portion is more At 91%.

In both of Example 1 and Example 2, more than 80% of the heat of reaction generated in the phenol hydrogenation reaction portion was applied to steam production.

Claims (15)

An industrial scale continuous process for the production and recovery of cyclohexanone from phenol and hydrogen, the process comprising: I) in a phenol hydrogenation reaction section [I], in a phenol hydrogenation reactor, comprising platinum and/or palladium In the presence of a catalyst, gaseous hydrogen is used to hydrogenate the phenol, thereby generating heat of reaction and discharging the hydrogenated product stream therefrom; II) in the separation and purification section [II], from the hydrogenation by multiple steps including the following The cyclohexanone is separated from the product stream: i. in the first distillation section, the component having a lower boiling point than cyclohexanone is removed; ii. in the second distillation section, the cyclohexanone is removed; iii. In the third distillation section, removing the cyclohexanol-rich phase; and iv. in the fourth distillation section, removing the mixture comprising phenol and cyclohexanol; wherein the cyclohexanone has less than 5000 ppm (weight/weight) a cyclohexanol content; wherein at least some of the heat of reaction generated in the phenol hydrogenation reaction portion [I] is applied to steam production; and the mixture comprising phenol and cyclohexanol removed in step iv) Filling the phenol hydrogenation reaction portion [I]; characterized by applying at least one of conditions a) or b): a The molar ratio of cyclohexanone to phenol charged to the phenol hydrogenation reactor is 0.02 to 0.10; b. The molar ratio of cyclohexanol to phenol charged to the phenol hydrogenation reactor is from 0.001 to 0.10. The method of claim 1, wherein the cyclohexanone to phenol molar ratio of the phenol hydrogenation reactor is 0.02 to 0.10, and the molar ratio of cyclohexanol to phenol charged in the phenol hydrogenation reactor is 0.001 To 0.10. The method of claim 1 or 2, wherein the method further comprises dehydrogenating cyclohexanol to cyclohexanone and hydrogen in the cyclohexanol dehydrogenation reaction portion [III]. The method of claim 1 or 2, wherein the molar ratio of cyclohexanone to cyclohexanol is greater than 10 in the hydrogenated product stream withdrawn in step I). The method of claim 1 or 2, wherein the cyclohexanone to phenol molar ratio is greater than 10 in the hydrogenated product stream withdrawn in step I). The method of claim 3, wherein the hydrogen produced in the cyclohexanol dehydrogenation reaction portion [III] is charged into the phenol hydrogenation reaction portion [I]. The method of claim 1 or 2, wherein the phenolic system is hydrogenated in a gas phase process. The method of claim 1 or 2, wherein the net vapor consumption is less than 1.5 kg of vapor per kilogram of cyclohexanone produced. The method of claim 1 or 2, wherein the net energy consumption is less than 3 million joules per kilogram of cyclohexanone produced. The method of claim 1 or 2, wherein the cyclohexanone has a cyclohexanol content of less than 2000 ppm (weight/weight). The method of claim 1 or 2, wherein the catalyst is palladium on an alumina support and a Na-containing salt as a promoter. The method of claim 1 or 2, wherein the catalyst is 1% by weight of palladium on the alumina support, and 1% by weight of Na is added as a promoter (in the form of NaHCO ₃ ). The method of claim 1 or 2, wherein more than 98% (mol/mole) of the phenolic system charged to the process is converted to cyclohexanone. The method of claim 1 or 2, wherein the selectivity per pass in the phenol hydrogenation reaction portion [I] is more than 92%, and wherein each pass in the phenol hydrogenation reaction portion [I] The phenol conversion system is more than 90%. An industrial scale continuous chemical plant for producing and recovering cyclohexanone from phenol and hydrogen, the plant comprising: I) a phenol hydrogenation reaction portion [I] comprising a phenol hydrogenation reactor, wherein the phenol is comprised of platinum and / or in the presence of a palladium catalyst, hydrogenation using gaseous hydrogen, thereby generating a heat of reaction and discharging the hydrogenated product stream therefrom; II) separating and purifying the fraction [II] from which the hydrogenation is carried out by multiple steps including the following Cyclohexanone is isolated from the product stream: i. a first distillation portion where components having a lower boiling point than cyclohexanone are removed; ii. a second distillation portion where cyclohexanone is removed; iii. a third distillation portion where the cyclohexanol-rich phase is removed; and iv. a fourth distillation portion where the mixture comprising phenol and cyclohexanol is removed; wherein the cyclohexanone has less than 5000 ppm (weight/weight) a cyclohexanol content; wherein at least some of the heat of reaction generated in the phenol hydrogenation reaction portion [I] is applied to steam production; and the mixture comprising phenol and cyclohexanol removed in step iv) Filling the phenol hydrogenation reaction portion [I]; characterized by applying at least one of the conditions a) or b): a. The molar ratio of cyclohexanone to phenol charged to the phenol hydrogenation reactor is 0.02 to 0.10 b. The molar ratio of cyclohexanol to phenol charged to the phenol hydrogenation reactor is 0.001 to 0.10.