Cylindrical reactor and use thereof for continuous hydroformylation

Abstract

Proposed is a cylindrical reactor (1) having a vertical longitudinal axis for continuous hydroformylation of a C.sub.6-C.sub.20-olefin or a mixture of C.sub.6-C.sub.20-olefins with synthesis gas in the presence of a homogeneously dissolved metal carbonyl complex catalyst, having a multiplicity of Field tubes (2) which are oriented parallel to the longitudinal axis of the reactor (1) and welded into a tube plate at the upper end of the reactor (1), having a circulation tube (3) open at both ends which envelops the Field tubes (2) and at its lower end projects beyond said tubes, having a jet nozzle (4) at the bottom of the reactor (1) for injecting the reactant mixture comprising the C.sub.6-C.sub.20-olefin, the synthesis gas and the metal carbonyl complex catalyst, wherein the Field tubes (2) are configured in terms of their number and their dimensions such that the total heat exchanger area of said tubes per unit internal volume of the reactor is in the range from 1 m.sup.2/m.sup.3 to 11 m.sup.2/m.sup.3 and the cross sectional area occupied by the Field tubes (2) per unit cross sectional area of the circulation tube (3) is in the range from 0.03 m.sup.2/m.sup.2 to 0.30 m.sup.2/m.sup.2, a gas distributor ring (5) is provided at the lower end of the circulation tube (3), at the inner wall thereof, via which a substream of the synthesis gas is feedable, and wherein one or more distributor trays (6) are provided in the circulation tube (3).

Claims

1. A cylindrical reactor (1) having a vertical longitudinal axis, having a multiplicity of Field tubes (2) which are oriented parallel to the longitudinal axis of the reactor (1) and affixed to the upper end of the reactor (1), having a tube insert (3) open at both ends which envelops the Field tubes (2) and at its lower end projects beyond said tubes, having an inlet nozzle (4) or a plurality of inlet nozzles (4) at the bottom of the reactor (1) for injecting a reactant mixture comprising at least one gaseous component and at least one liquid component, wherein the Field tubes (2) are configured in terms of their number and their dimensions such that the total heat transfer area of said tubes per unit internal volume of the reactor is in the range from 1 m.sup.2/m.sup.3 to 12 m.sup.2/m.sup.3 and the cross sectional area occupied by the Field tubes (2) per unit cross sectional area of the tube insert (3) is in the range from 0.03m.sup.2/m.sup.2 to 0.30 m.sup.2/m.sup.2.

2. The cylindrical reactor (1) according to claim 1, wherein the cross sectional area of the tube insert (3) per unit cross sectional area of the reactor (1) is 0.60 m.sup.2/m.sup.2 to 0.75 m.sup.2/m.sup.2, preferably 0.66 m.sup.2/m.sup.2 to 0.72 m.sup.2/m.sup.2.

3. The cylindrical reactor (1) according to claim 1, wherein said reactor comprises a gas distributor ring (5) at the lower end of the tube insert (3) at the inner wall thereof via which a substream of the gaseous component of the reactant mixture is fed.

4. The cylindrical reactor (1) according to claim 1, wherein said reactor comprises a holding device (6) or a plurality of holding devices (6) in the tube insert (3).

5. The cylindrical reactor (1) according to claim 1, wherein said reactor comprises a static mixer (6a) or a plurality of static mixers (6a) in the tube insert (3).

6. The cylindrical reactor (1) according to claim 4, wherein one or more of the holding devices (6) additionally function as static mixers.

7. The cylindrical reactor (1) according to claim 1, wherein the Field tubes (2) are configured in terms of their number and their dimensions such that the total heat transfer area of said tubes per unit internal volume of the reactor is in the range from 7 m.sup.2/m.sup.3 to 11 m.sup.2/m.sup.3 and the cross sectional area occupied by the Field tubes (2) per unit cross sectional area of the tube insert (3) is in the range from 0.07 m.sup.2/m.sup.2 to 0.25 m.sup.2/m.sup.2.

8. The cylindrical reactor (1) according to claim 1, wherein the tube insert (3) envelops the Field tubes (2) to an extent of 80% of the length thereof, preferably to an extent of 90% of the length thereof.

9. The cylindrical reactor (1) according to claim 1, wherein said reactor comprises a baffle plate (7) above the tube insert (3).

10. A continuous process for producing C.sub.7-C.sub.21-oxo products by hydroformylation of at least one C.sub.6-C.sub.20-olefin with synthesis gas in the presence of a homogeneously dissolved transition metal catalyst, wherein the process is carried out in a cylindrical reactor (1) having a vertical longitudinal axis, having a multiplicity of Field tubes (2) which are oriented parallel to the longitudinal axis of the reactor (1) and welded into a tube plate at the upper end of the reactor (1), having a tube insert (3) open at both ends which envelops the Field tubes (2) and at its lower end projects beyond said tubes, having an inlet nozzle (4) or a plurality of inlet nozzles (4) at the bottom of the reactor (1) for injecting a reactant mixture comprising the C.sub.6-C.sub.20-olefin, the synthesis gas and optionally the transition metal catalyst, wherein the Field tubes (2) are configured in terms of their number and their dimensions such that the total heat transfer area of said tubes per unit internal volume of the reactor is in the range from 1 m.sup.2/m.sup.3 to 12 m.sup.2/m.sup.3 and the cross sectional area occupied by the Field tubes (2) per unit cross sectional area of the tube insert (3) is in the range from 0.03 m.sup.2/m.sup.2 to 0.30 m.sup.2/m.sup.2.

11. The process according to claim 10, wherein the transition metal catalyst is a metal carbonyl complex catalyst, preferably a cobalt carbonyl complex catalyst.

Description

DESCRIPTION OF FIGURES

(1) FIG. 1 shows a longitudinal section through a preferred embodiment of a reactor according to the invention.

(2) FIG. 2 shows a longitudinal section through an individual Field tube.

(3) FIG. 2a shows a detailed view of an individual Field tube in a holding device with protuberances attached to the outer wall of the Field tube above and below the holding device.

(4) FIG. 3 shows a schematic view of the liquid flow through the embodiment depicted in FIG. 1.

(5) FIG. 4 shows a detailed drawing of the lower reactor region in the configuration having a gas distributor ring.

(6) FIG. 5 shows a cross section through a reactor depicted in FIG. 1.

(7) In the figures identical reference numerals describe respective identical or corresponding features. 1 reactor 2 Field tubes 3 tube insert 4 inlet nozzle 5 gas distributor ring 6 holding device 6a holding device and static mixer 7 baffle plate 8 reactor shell 9 annular space 10 outer tube 11 inner tube 12 reactor head 13 lifting lugs 14 protuberances 15 spacers

(8) The longitudinal section in FIG. 1 shows a schematic view of a preferred cylindrical reactor 1 having a vertical longitudinal axis having a multiplicity of Field tubes 2 and a reactor head 12 shown in schematic form. The Field tubes 2 are welded into a tube plate at the upper end of the reactor 1 which in the present case forms the lower end of the reactor head 12. Arranged coaxially in the reactor 1 is a tube insert 3 open at both ends which envelops the Field tubes 2 and at its lower end projects beyond said tubes. The reactor head comprises, inter alia, parts of the coolant circuit for distributing the inflowing cold coolant to the individual Field tubes 2 and for discharging the heated coolant exiting the individual Field tubes 2 and the vapor formed (not shown). The reactor head 12 further comprises the outlet for the reaction mixture, it being possible to discharge gaseous and liquid components together. Feeding of the reactants is effected via an inlet nozzle 4 at the lower end of the reactor 1. The inlet nozzle 4 is configured as an ejector nozzle by means of which the C.sub.6-C.sub.20-olefins and the synthesis gas are simultaneously fed. If desired, aqueous transition metal catalyst, in particular the metal carbonyl complex catalyst, may additionally be fed to nozzle 4 with one of the streams. A substream of the synthesis gas may be fed via a gas distributor ring 5 at the lower end of the tube insert 3. By way of example, a holding device configured as static mixer 6a and two further holding devices 6 are depicted in the tube insert 3. Disposed above the tube insert 3 is a baffle plate 7 arranged perpendicularly to the tube insert 3.

(9) By way of example, FIG. 2 shows a schematic view of an individual Field tube 2 which is in each case composed of a sleeve, referred to here and in what follows as outer tube 10, and a coaxial inner tube 11. The outer tube 10 is closed at its lower end while the coaxial inner tube 11 is open at its lower end. In the embodiment depicted coolant, for example water, in particular boiler feed water, may be introduced into the inner tube 11 from above and withdrawn at the upper end of the outer tube 10 as heated coolant, for example as a vapor-liquid mixture. The coolant is typically passed downward through the inner tube and passed upward between the inner tube 11 and the outer tube 10. However, the coolant flow may alternatively be reversed. The feed and discharge for the coolant which flows through the Field tubes 2 are typically integrated into the reactor head 12. To this end the reactor head 12 may comprise, for example, two separate compartments, wherein one is provided with the inlet for the coolant and distributes the coolant into the Field tubes 2 and the other receives the heated coolant flowing out of the Field tubes 2, said coolant then exiting the reactor head 12 through an outlet.

(10) FIG. 2a shows a detailed view of an individual Field tube 2 in a holding device 6. Attached to the outer wall of the Field tube 2 above and below the holding device 6 are protuberances which form a bearing for the holding device 6.

(11) FIG. 3 illustrates the liquid flow in the reactor 1 depicted in FIG. 1. This liquid flow is depicted schematically with arrows. Inside the tube insert 3 an upward flow is induced by the jet nozzle 4. The baffle plate 7 deflects the flow to provide a downward flow in annular space 9 between the reactor inner wall and the tube insert 3.

(12) FIG. 4 shows a detailed drawing of the lower reactor region of an embodiment according to the invention. This shows the reactor 1 comprising a jet nozzle 4 for injecting the reactant mixture. A substream of the synthesis gas may be fed to the reactor 1 via a gas distributor ring 5 at the lower end of the tube insert 3.

(13) FIG. 5 shows a cross section through the reactor shown in FIG. 1 at a point where no holding device is present. This cross section is referred to here and in what follows as a tubesheet. The tubesheet shows the number, relative dimensions and arrangement inside the tube insert 3 of the Field tubes each composed of an outer tube 10 and a coaxial inner tube 11. The figure depicts a possible equilateral triangular arrangement of the Field tubes in the tube insert 3 also known as a staggered tube arrangement. A square arrangement of the Field tubes in the tube insert also known as an aligned tube arrangement would likewise be suitable.

(14) The tube insert 3 is arranged coaxially with the reactor shell 8 and envelops the Field tubes each composed of an outer tube 10 and a coaxial inner tube 11. Disposed between the reactor shell 8 and the tube insert is an annular space 9. The spacers 15 are distributed over the circumference of the annular space 9 in accordance with the tube arrangement. In the present case said spacers form an equilateral triangle though a regular hexagonal arrangement or, in the case of an aligned arrangement, a square arrangement would also be suitable. The spacers 15 are here intended to be merely implied since they are preferably disposed at the same height as a holding device.

EXAMPLES

Example 1

(15) A hydroformylation plant comprising a main reactor and a postreactor is employed. The main reactor is 18.0 m in length and has an internal diameter of 1.0 m. The upper tube plate which is simultaneously the lid of the reactor is fitted with 64 Field tubes having an external diameter of 30.0 mm. A tube insert having an internal diameter of 0.84 m is disposed in the main reactor. The reactants (isooctene and synthesis gas comprising 40 vol % carbon monoxide and 60 vol % hydrogen) and the aqueous cobalt acetate solution are introduced via a nozzle at the bottom of the reactor. The main reactor is operated at 187 C. and 275 bar. The temperature in the postreactor is at the same level but the pressure is held at 3 bar below the pressure in the main reactor. 1 t/h of synthesis gas and 3 t/h of isooctene produced as per WO 95/14647 were employed.

(16) The ratio of the total heat transfer area of the Field tubes per unit internal volume of the main reactor is 9.4 m.sup.2/m.sup.3. The cross sectional area occupied by the Field tubes per unit cross sectional area of the tube insert is 0.08 m.sup.2/m.sup.2.

(17) Isononanol is produced in this hydroformylation plant. In order to compensate for losses due to cobalt deposited in the reactor it is necessary to supplement 160 kg of cobalt as cobalt acetate solution over the course of one year. This corresponds to 0.01 kg of cobalt per ton of product.

(18) This reactor was operated for five years before the cobalt deposits were removed using dilute nitric acid (see international patent application WO2015/018 710).

Comparative Example

(19) The plant and the operating conditions are identical to those in inventive example 1. However, in departure therefrom the main reactor is fitted with 158 Field tubes having an external diameter of 48.3 mm and the tube insert has an internal diameter of 1.23 m.

(20) The ratio of the total heat transfer area of the Field tubes per unit internal volume of the reactor is 16.1 m.sup.2/m.sup.3. The cross sectional area occupied by the Field tubes per unit cross sectional area of the tube insert is 0.25 m.sup.2/m.sup.2.

(21) In this hydroformylation plant isononanol is likewise produced from isooctene and synthesis gas comprising 40 vol % carbon monoxide and 60 vol % hydrogen with the aid of a cobalt catalyst. The main reactor is operated at 187 C. and 275 bar. The temperature in the postreactor is at the same level but the pressure is held at 3 bar below the pressure in the main reactor. 1 t/h of synthesis gas and 3 t/h of isooctene produced as per WO 95/14647 were employed.

(22) Over the course of one year it is necessary to supplement 5000 kg of cobalt as cobalt acetate solution to compensate the losses due to cobalt deposited in the reactor. This corresponds to 0.06 kg of cobalt per ton of product; the cobalt losses are thus markedly higher compared to the inventive example.

(23) Blockages in the pipes occurred after approximately one year and the cobalt deposits had to be removed using dilute nitric acid to remove the blockage.