Combination reactor system

Abstract

The present invention is directed to a combination reactor system for exothermic reactions comprising a trickle-bed reactor and a shell-and-tube reactor. This combination allows the system to efficiently remove heat while also providing the ability to control both the temperature and/or reaction progression. The trickle-bed reactor removes heat efficiently from the system by utilizing latent heat and does not require the use of a cooling or heating medium. The shell-and-tube reactor is used to further progress the reaction and provides a heat exchanger in order to introduce fluid at the desired temperature in the shell-and-tube reactor. Also, additional reactant or reactants and/or other fluids may be introduced to the shell-and-tube section of the reactor under controlled temperature conditions.

Claims

1. A reactor system for use with an exothermic reaction comprising the hydrogenation of a fluoro-olefin compound, said system comprising in combination, (a) as a first reactor in the system, a trickle-bed reactor which does not include either a heating or cooling medium, and (b) as a second reactor in the system, a shell-and-tube reactor which comprises a temperature control system selected from the group consisting of a heating medium, a cooling medium, and both a heating and a cooling medium, wherein the reactors are separated by a heat exchanger; wherein the trickle bed reactor comprises a fixed bed of reactor catalyst and two phases in the reactor; wherein the shell-and-tube reactor comprises a multi-stage, multi-tube, shell-and-tube heat exchanger which contains reactor catalyst in all tubes; and wherein the reactor system provides for the removal of heat and provides the ability to control reaction temperature and/or reaction progression.

2. The combination reactor system of claim 1, wherein the heat exchanger is used for removing or adding heat or causing a phase change of a reaction medium.

3. The combination reactor system of claim 1, wherein the trickle-bed reactor removes heat from the system by utilizing latent heat.

4. The reactor system of claim 1, wherein the hydrogenation reaction is the conversion of hexafluoropropylene to 1,1,1,2,3,3-hexafluoropropane.

5. The reactor system of claim 1, wherein the hydrogenation reaction is the conversion of 1,2,3,3,3-pentafluoropropene to 1,1,1,2,3-pentafluoropropane.

6. A combination reactor system for use with an exothermic reaction comprising the hydrogenation of a fluoro-olefin compound, said system comprising in combination, (a) a trickle-bed reactor as the first reactor in the system; and (b) a shell-and-tube reactor as the second reactor in the system; wherein the trickle-bed reactor removes heat from the system by utilizing latent heat and does not require the use of a cooling or heating medium; wherein the shell-and-tube reactor comprises a shell structure and a tubesheet located in the shell structure; wherein the tubesheet comprises one or more reaction zones and one or more temperature control zones, wherein each reaction zone comprises a plurality of aligned reaction tubes; and each temperature control zone comprises a plurality of aligned temperature control tubes; wherein the reactor system further comprises a heat exchanger in order to introduce materials to the reactors at predetermined temperatures, thereby controlling the reaction conditions in the combination reactor system; and wherein each reaction zone of the shell-and-tube reactor is adjacent to a temperature control zone.

7. The reactor system of claim 6, wherein the hydrogenation reaction is the conversion of hexafluoropropylene to 1,1,1,2,3,3-hexafluoropropane.

8. The reactor system of claim 6, wherein the hydrogenation reaction is the conversion of 1,2,3,3,3-pentafluoropropene to 1,1,1,2,3-pentafluoropropane.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 illustrates one embodiment of the combination reactor system of the present invention, showing a combined trickle bed reactor and a shell and tube reactor system.

(2) FIG. 2 illustrates one embodiment of a trickle bed reactor useful in the combination reactor system of the present invention.

(3) FIG. 3 illustrates one embodiment of a shell and tube reactor useful in the combination reactor system of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

(4) As described above, the present invention is directed to a combination reactor system comprising a trickle-bed reactor connected to a shell-and-tube reactor. This reactor combination is especially useful for conducting exothermic reactions, i.e., reactions that are accompanied by the evolution of heat as the reaction occurs. Highly exothermic reactions, i.e., reactions that produce high temperatures can be safely conducted in the combination reactor system of the present invention. Typically, hydrogenation, oxidation and chlorination are recognized as highly exothermic reactions.

(5) This system allows the reaction operators to efficiently add and/or remove heat from the reaction system while also providing the ability to control both the temperature and/or reaction progression. The trickle-bed reactor removes heat efficiently from the system by utilizing latent heat and does not require a cooling or heating medium. The shell-and-tube reactor is used to further progress the reaction and to provide rapid heat exchange ability should the reaction progress not be meeting desired requirements.

(6) As illustrated in FIGS. 1, 2 and 3, the combination reactor system of the present invention comprises a trickle-bed reactor followed by a shell-and-tube reactor. This system allows highly exothermic reactions to precede under the precise control of the system operators, as the combined reactor system allows for the efficient addition and/or removal of heat from the reaction, while also providing the ability to control both the temperature and/or reaction progression.

(7) FIG. 1 illustrates one embodiment of a combination reactor system of the present invention, comprising a trickle-bed reactor 100 mounted to a shell-and-tube reactor 300. As shown therein, the upper reactor is the trickle bed reactor 100. This reactor includes a reactant inlet nozzle 110 and a relief nozzle 120 at the top part of the reactor. Internally, this reactor includes an inlet baffle 130 and an inlet distributor 140. Also shown are the catalyst fill nozzle 150, a thermowell 160, a catalyst removal nozzle 170, and a catalyst support grid 180.

(8) A liquid collector tray 190, is placed between the between the two reactor sections. Gas will continue to flow down to the shell & tube reactor, whereas liquid product may be optionally withdrawn from the system via liquid drawoff nozzle 200. Should any additional reactants be required at this stage of the processing, they may be added via intermediate feed nozzle 210.

(9) As further illustrated in FIG. 1, the bottom portion of the combination reactor system of the present invention includes the shell and tube reactor 300. This reactor includes an upper shell nozzle 310 and a lower shell nozzle 320. One of the multiple reactor tubes 330 is shown in the reactor, and each tube includes a tube cover 340. The tubes are positioned in the reactor with a baffle 350. The reactor outlet nozzle 360 is shown at the bottom.

(10) The trickle-bed removes reaction heat efficiently from the system by utilizing latent heat and does not require a cooling or heating medium. One embodiment of such a reactor is shown in FIG. 2. As shown therein, the reactor includes a bed of catalyst, and various inlet and outlet ports, baffles and distributors for conducting reactions therein.

(11) As illustrated in FIG. 2, the reactor includes the following components; A1reactant inlet nozzle V1relief nozzle N1catalyst fill nozzle T1thermowell N2catalyst (HK) outlet nozzle B1reactor outlet nozzle

(12) The shell-and-tube reactor is used to further progress the reaction and to provide heat exchange ability should the reaction progress past the desired process design. One embodiment of such a reactor is shown in FIG. 3. As shown therein, the reactor includes tubes of supported catalyst, and various inlet and outlet ports, baffles and distributors for conducting reactions therein.

(13) As illustrated in FIG. 3, the reactor includes the following; 10Tube nozzle 12Divider 14Baffle Plate 16Head 18Tube 20Tube cover 22Catalyst support 24Tubesheet 26Shell 28Shell nozzle 30Baffle 32Support lug

(14) As described above, if desired these reactors can be separated by a heat exchanger in order to introduce fluid at the desired temperature to the shell-and-tube reactor.

(15) If desired, additional reactant or reactants and/or other fluids may be introduced to the shell-and-tube section of the reactor.

(16) The trickle-bed and shell-and-tube or trickle-bed, heat exchanger, and shell-and-tube setup can be done in a way so as to provide the optimal system for reaction progress and heat exchange as required by any process.

(17) In one embodiment, the pieces of equipment are stacked with the trickle-bed reactor on top and shell-and-tube reactor on the bottom; thereby preserving floor space. Here, the trickle bed reactor is similar to the trickle-bed normally used in chemical engineering with a fixed bed of reactor catalyst and two phases in the reactor. The shell-and-tube reactor is a multi-stage, multi-tube, multi-heating zone, shell-and-tube heat exchanger which contains reactor catalyst in certain tubes and optionally, no catalyst in other tubes. See U.S. Patent Pub. No. 2010-0307726 A1. For another preferred design, see U.S. Patent Pub. No. 2011-0054226 A1.

(18) However, a simpler shell-and-tube reactor design could be used, depending on the reaction and/or systems requirements. The heat exchanger could be a traditional heat exchanger used for removing or adding heat or causing a phase change of the process fluid. Even in the case of a traditional shell & tube reactor, some or all of the tubes may be filled with catalyst.

(19) As described above, the present invention is preferably designed for use with exothermic reactions. For example, reactions involving the catalytic hydrogenation of fluoro-olefins are typically exothermic, and these reactions are one preferred type of reaction that may be conducted in the combination reactor of the present invention. In such a case the reactor should be constructed from materials which are resistant to the corrosive effects of the reagents employed therein. Typical materials for the reactors include metals such as nickel and its alloys, including Hastelloy, Inconel, Incoloy, and Monel or vessels lined with fluoropolymers. Other suitable materials used under suitable conditions could be steel or stainless steel.

(20) The process flow may either be in the down or up direction through a bed of the catalyst in the shell and tube reaction zones. If the reaction zones require heating for optimal reaction, one or more of the temperature control zones is charged with a heating medium that provides sufficient heat to the reaction zones to provide the desired reaction temperature. Materials suitable for use as a heating medium are well known to persons having ordinary skill in this art, and include for example, hot tempered water, hot oil, and condensing steam. Similarly, if the reaction zones require cooling to maintain optimal reaction conditions, one or more of the temperature control zones is charged with a suitable cooling medium that removes heat and achieves or maintains the desired temperature in the reaction zones. Materials suitable for use as a cooling medium are well known to persons having ordinary skill in this art, and include for example, cooling water and boiling water.

(21) In commercial processes where a fluoro-olefin C.sub.(n)H.sub.(2n-x)F.sub.(x) to C.sub.(n)H.sub.(2nx+2)F.sub.(x) is hydrogenated (e.g., hexafluoropropylene to 236ea, 1225ye to 245eb, and the like), inadequate management or control of heat removal may induce excess hydrogenation, decomposition and hot spots resulting in reduced yields and potential safety issues. In the hydrogenation of fluoro-olefins, it is therefore necessary to control the reaction temperature as precisely as practical to overcome challenges associated with heat management and safety.

REACTION EXAMPLES

(22) Particularly useful reactions to make use of this invention include the following:
Hexafluoropropylene+H.sub.2.fwdarw.1,1,1,2,3,3-hexafluoropropane(HFC-236ea);Reaction (1)
and
1,2,3,3,3-pentafluorpropene (HFC-1225ye)+H.sub.2.fwdarw.1,1,1,2,3-pentafluoropropane (HFC-245eb).Reaction (2)

(23) Note, an undesired over-hydrogenation product in Reaction (2) is 1,1,1,2-tetrafluoro-propane (HFC-254eb).

(24) As used herein, the singular forms a, an and the include plural unless the context clearly dictates otherwise. Moreover, when an amount, concentration, or other value or parameter is given as either a range, preferred range, or a list of upper preferable values and lower preferable values, this is to be understood as specifically disclosing all ranges formed from any pair of any upper range limit or preferred value and any lower range limit or preferred value, regardless of whether ranges are separately disclosed. Where a range of numerical values is recited herein, unless otherwise stated, the range is intended to include the endpoints thereof, and all integers and fractions within the range. It is not intended that the scope of the invention be limited to the specific values recited when defining a range.

(25) While the present invention has been particularly shown and described with reference to preferred embodiments, it will be readily appreciated by those of ordinary skill in the art that various changes and modifications may be made without departing from the spirit and scope of the invention. It is intended that the claims be interpreted to cover the disclosed embodiment, those alternatives which have been discussed above and all equivalents thereto.