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CN-116997410-B - Method for oligomerization in a reactor comprising a gas/liquid double distributor

CN116997410BCN 116997410 BCN116997410 BCN 116997410BCN-116997410-B

Abstract

The present invention relates to a gas/liquid reactor for the oligomerization of gaseous ethylene comprising gaseous ethylene injection means and liquid injection means, said injection means advantageously being arranged such that the injection of liquid is capable of causing a reduction in ethylene bubble size by shearing during the injection of gaseous ethylene. The gas/liquid reactor according to the present invention may be used for any gaseous olefin feedstock injected into the liquid phase.

Inventors

  • L. Renal
  • A. Vonner
  • P. Maximiliano Lemondo

Assignees

  • IFP 新能源公司

Dates

Publication Date
20260505
Application Date
20211214
Priority Date
20201223

Claims (15)

  1. 1. A process for the oligomerization of a gaseous olefin feedstock comprising contacting a liquid comprising a catalytic system with the gaseous olefin feedstock by means of a gas injection device and a liquid injection device, the catalytic system comprising a metal catalyst, at least one activator and at least one additive, the injection device being arranged such that injection of the liquid causes a reduction in gaseous ethylene bubble size by shearing, the process using a gas/liquid reactor for the oligomerization of the gaseous olefin feedstock, the gas/liquid reactor comprising a gas injection device (3), a liquid injection device (12) and a reaction chamber, the gas injection device comprising at least one gas injection orifice, the reaction chamber having an elongated shape along a vertical axis, the reaction chamber comprising a liquid phase in a lower region and a gas phase in an upper region above the lower region, the lower region of the reaction chamber comprising an upper portion and a lower portion, the liquid injection device being arranged with the gas injection device, the liquid injection device and the gas injection device being located in the lower portion of the reaction chamber, the liquid injection device comprising at least one gas injection orifice, each liquid orifice being located such that the liquid is able to be injected in a trajectory in which the liquid is caused to be injected by the shearing of the liquid during the trajectory when the liquid is located in the vicinity of the gas injection device.
  2. 2. The process of claim 1, wherein the liquid injection orifice and the gas injection orifice are circular, and wherein the liquid injection orifice has a diameter that is greater than or equal to the diameter of the gas injection orifice.
  3. 3. The process of claim 1, wherein the at least one gas injection orifice and the at least one liquid injection orifice are positioned to face each other at an angle between 0 ° and 180 °.
  4. 4. A process according to any one of claims 1-3, wherein the gas injection device and the liquid injection device are selected from the group consisting of tubes, webs of tubes, multi-tube distributors, perforated plates, cylindrical tubes and concentric tubes.
  5. 5. The process of claim 4, wherein the gas injection device is a cylindrical tube in the form of a ring with injection orifices and the liquid injection device is a cylindrical tube in the form of a ring with injection orifices.
  6. 6. The process of claim 5, wherein the gas injection device in the form of a torus has a diameter that is smaller than the liquid injection device in the form of a torus, and wherein the gas injection device is positioned inside the liquid injection device on a different plane.
  7. 7. A process according to claim 6, wherein a series of several liquid and gas injection means in the form of rings of decreasing diameter alternate from the periphery to the centre represented by the central axis of the means having the largest diameter, the means being positioned such that the gas injection orifices of the gas injection means are positioned close to the orifices of the adjacent liquid injection means such that the injection trajectories of the liquid and gas are in the same plane, thereby causing shearing of the gas.
  8. 8. A process according to any one of claims 1-3, wherein the orifices of the gas injection device and the liquid injection device each extend through a tube (13, 15).
  9. 9. A process according to claim 8, wherein the diameter of the tube (13) of the gas injection device (3) is smaller than the diameter of the tube (15) of the liquid injection device (12), and the open outlet end of the tube (13) of the gas injection device (3) is coaxially positioned inside the liquid injection tube.
  10. 10. A process according to any one of claims 1-3, wherein the liquid injection tube (15) comprises a deflector.
  11. 11. A process as claimed in any one of claims 1-3, wherein the end of the liquid injection tube (15) has a taper of outlet diameter.
  12. 12. A process according to any one of claims 1-3, wherein: The liquid phase comprises the reaction product, dissolved and gaseous olefin feed, catalytic system and solvent, The gas phase comprises the gaseous olefin feed and also non-condensable gases, The process comprises the following steps: means for introducing the catalytic system, said means being located in a lower portion of the reaction chamber, A recirculation circuit comprising extraction means for extracting a liquid portion at the base of the reaction chamber, a heat exchanger for cooling the liquid and means for introducing the cooled liquid, the introduction means being located in an upper portion of the lower zone of the reaction chamber, -A gas phase recovery loop for recovering at least a portion of the gas phase into the lower region of the liquid phase, the gas phase recovery loop comprising extraction means located in the upper region of the reaction chamber to enable extraction of a gas portion in the gas phase and introduction means located in the lower region of the reaction chamber to enable introduction of the extracted gas portion into the liquid phase.
  13. 13. A process according to any one of claims 1-3, wherein the gaseous olefin feed comprises from 2 to 6 carbon atoms.
  14. 14. A process according to any one of claims 1 to 3 wherein the liquid injection velocity is greater than the gaseous olefin feed injection velocity, thereby facilitating shearing the olefin bubble size into bubbles of smaller size.
  15. 15. The process of claim 12, wherein the non-condensable gas is ethane.

Description

Method for oligomerization in a reactor comprising a gas/liquid double distributor Technical Field The present invention relates to the technical field of gas/liquid reactors for oligomerising olefins to linear olefins by homogeneous catalysis. The invention also relates to the use of the gas/liquid reactor in a process for the oligomerization of gaseous olefin feed, preferably gaseous ethylene, to produce linear alpha-olefins such as 1-butene, 1-hexene or 1-octene or a mixture of several linear alpha-olefins. Background The present invention relates to the technical field of gas/liquid reactors, also known as bubble columns, and also to their use in processes for the oligomerization of olefin feedstocks, preferably ethylene. One disadvantage encountered during the use of such reactors in ethylene oligomerization processes is the management of the gaseous headspace corresponding to the upper portion of the reactor in the gaseous state. The gaseous headspace includes gaseous compounds that are slightly soluble in the liquid phase, compounds that are partially soluble in the liquid but inert, and also gaseous ethylene that is insoluble in the liquid. The transfer of gaseous ethylene from the liquid lower portion of the reaction chamber to the gaseous headspace is a phenomenon known as breakthrough. In practice, the gaseous headspace is vented in order to remove the gaseous compounds. When the amount of gaseous ethylene present in the gaseous headspace is high, gassing of the gaseous headspace results in a non-negligible loss of ethylene, which is detrimental to the productivity and cost of the oligomerization process. Furthermore, the significant breakthrough phenomenon means that a large amount of gaseous ethylene has not yet dissolved in the liquid phase and thus has not yet reacted, which is detrimental to the productivity and selectivity of the oligomerization process. In order to increase the efficiency of the oligomerization process, in particular in terms of productivity and cost, it is therefore very important to limit the breakthrough phenomenon of ethylene in order to increase its conversion in the process, while at the same time maintaining good selectivity to the desired linear alpha-olefin. The prior art process using a gas/liquid reactor as illustrated in fig. 1 cannot limit the loss of gaseous ethylene and the purging of the gaseous headspace results in gaseous ethylene exiting the reactor, which is detrimental to the yield and cost of the process. In patent applications WO 2019/0116806 and WO 2019/01609, the applicant describes a process that enables an increase in the contact surface area between the upper part of the liquid part and the gaseous head space by means of dispersing means or vortexing, so as to promote the transfer of the ethylene contained in the gaseous head space towards the liquid phase at the liquid/gas interface. These processes cannot limit breakthrough and are inadequate when the amount of ethylene in the gas headspace is large due to high breakthrough levels. Furthermore, during its research studies, the applicant has found that in a reactor operating at a constant flow rate of injected gaseous ethylene, the quantity of dissolved ethylene and the breakthrough phenomenon depend on the bubble size of the injected gaseous ethylene. The time for gaseous ethylene to dissolve in the liquid phase corresponds to the travel time of the bubbles in the liquid level, which is determined by the operating conditions and the height of the reactor. The amount of gaseous ethylene dissolved per unit time is proportional to the contact area between the gas and liquid phases. The larger the bubble, the lower its area/volume ratio and the longer it takes to dissolve, which increases the penetration phenomenon for a given height of liquid phase. The applicant has found that the conversion of olefin(s) can be improved by limiting the breakthrough phenomenon by means of a specific gas/liquid reactor for the oligomerization of gaseous olefin feedstock (in particular gaseous ethylene), while at the same time maintaining a high selectivity for the desired linear olefin(s) and in particular for the alpha-olefin(s), comprising a gaseous ethylene injection means and a liquid injection means, advantageously arranged such that the injection of liquid is capable of causing a reduction of ethylene bubble size by shearing during the injection of gaseous ethylene. The gas/liquid reactor according to the present invention may be used for any gaseous olefin feedstock injected into the liquid phase. Disclosure of Invention The invention relates to a gas/liquid reactor for the oligomerization of gaseous olefin feedstock comprising gas injection means (3) and liquid injection means (12) arranged such that injection of liquid can cause a reduction in bubble size by shearing during injection of the gaseous olefin feedstock. Preferably, the gas injection device (3) comprises at least one gas injection orifice and