CN101367694A - Horizontal moving bed reactor for the production of propylene from oxygenates - Google Patents

Abstract

The invention provides a horizontal moving bed reactor for producing propylene with an oxygen-containing compound as a raw material. The spacer, the porous spacer divides the internal space of the shell into at least 4 areas arranged horizontally, the two areas at the end of the shell are respectively connected with the raw material inlet and the product outlet, and the remaining areas are reaction chambers arranged at intervals. zone and cooling zone; the shells corresponding to the upper and lower ends of the reaction zone are respectively provided with a catalyst inlet and a catalyst outlet, and the shell corresponding to the cooling zone is provided with a coolant inlet. The horizontal moving bed reactor of the invention is simple in structure, easy in equipment design, manufacture and maintenance, convenient in operation, easy in controlling reaction progress and maintaining good reaction conditions.

Description

Horizontal moving bed reactor for the production of propylene from oxygenates

technical field

The invention relates to a propylene production equipment, in particular to a horizontal moving bed reactor for producing propylene with oxygen-containing compounds as raw materials.

Background technique

Oxygenated propylene technology is a process for producing propylene from non-petroleum resources, which has great application prospects. According to numerous published literature reports, the production of propylene from oxygen-containing compounds is a strongly exothermic reaction type, and the selectivity of the target product propylene is relatively sensitive to temperature.

Among the relatively mature technologies for producing propylene from oxygenates in the world, the MTO process jointly developed by UOP/Hydro uses a fluidized bed reactor, which has better heat transfer effect and is easier to control the reaction temperature. Therefore, the requirements for the wear resistance of the catalyst are relatively high; Lurgi’s MTP process uses a fixed bed reactor with high propylene selectivity, but the heat transfer effect of the fixed bed reactor is poor, so Lurgi uses in its MTP process Various methods such as setting up pre-reactor, thin-layer main reactor, interstage cooling and adding quenching liquid are used to increase heat transfer and control reaction temperature.

The moving bed reactor has the characteristics of both fixed bed reactor and fluidized bed reactor, and is suitable for catalysts with fast carbon deposition but not fast. Chinese patent application 200610002109.4 discloses a method for converting oxygen-containing organic compounds into propylene using moving bed technology and an independent heavy olefin interconversion step. This method mainly improves the yield of propylene through the circulation of by-products. For moving bed reactors Did not carry out any improvement, more did not mention how to control the problems such as reaction temperature.

Chinese patent 85103262 discloses a multi-stage reactor system with a movable catalyst bed. There are multiple vertically separated catalytic reaction zones in the reactor, which belongs to the overlapping radial moving bed reactor type.

Chinese patent 03116945.7 discloses a continuous catalytic reforming reactor. The reactor adopts a circular container with a catalytic bed as the reaction device. The reactant inlet is located at the upper end of the reaction device, and the outlet is located at the lower end of the reaction device. The outer porous wall and the inner porous wall are composed of a cylinder, which is filled with catalyst. The catalyst flows continuously from top to bottom with the help of gravity. At the same time, the reaction material flows centrifugally from the center to the outside in the reaction device. The channels flow in the same direction from top to bottom, which is a Z-type centrifugal radial moving bed reactor.

The radial moving bed reactor is provided with only one catalytic reaction zone in the radial position, and no effective heat removal method is involved. This may be because the above radial moving bed reactor is mainly used in the catalytic reforming reaction, the reaction It is endothermic, so the design goal of the reactor is to reduce the heat loss in the reactor.

The reaction of converting oxygen-containing compounds into propylene is an exothermic reaction, and the above-mentioned reactor is not suitable for preparing propylene. In order to solve the problem of heat dissipation, a plurality of moving-bed reactors are often connected in order to solve the problem of heat dissipation. A heat exchanger is added between two adjacent moving bed reactors, which not only wastes energy, but also increases the complexity of the system and increases the manufacturing cost.

Contents of the invention

The invention provides a horizontal moving bed reactor for producing propylene with an oxygen-containing compound as a raw material. The reactor has a simple structure and can solve the problem that the selectivity of propylene is reduced due to the increase of the temperature of the raw material due to the exothermic reaction.

A horizontal moving bed reactor for producing propylene with an oxygen-containing compound as a raw material, comprising a shell, one end of the shell transversely is provided with a raw material inlet, the other end is provided with a product outlet, and the shell is provided with a porous partition, so The porous spacer described above divides the internal space of the housing into at least 4 regions arranged horizontally, and the two regions at the end of the housing are respectively connected with the raw material inlet and the product outlet, and the remaining regions are the reaction zone and the cooling zone arranged at intervals. ; The housing corresponding to the upper and lower ends of the reaction zone is respectively provided with a catalyst inlet and a catalyst outlet, and the housing corresponding to the cooling zone is provided with a coolant inlet.

The form of the porous partition can be various, the simplest way is to choose at least 3 screens arranged in parallel horizontally, which is not only simple in structure, but also easy to install and manufacture. requirements.

The catalyst is easily worn during the moving process. By setting a porous baffle on the side of the screen close to the reaction zone, the catalyst particles are not easy to pass through, and there is no significant obstacle to the flow of the material gas, and the specific diameter is not required.

The cooling liquid can enter the cooling zone in various ways. It is preferable to install a chilling liquid nozzle connected with the cooling liquid inlet in the cooling zone, so that the mixing is more uniform. The number of quench liquid nozzles in a single cooling zone can be arbitrary, preferably 4-64.

In order to better control the temperature of the reaction zone, a heat exchange tube is arranged in the reaction zone, and a heat exchange medium is passed through the heat exchange tube.

The total number of reaction zones and cooling zones is at least three. Since the reaction zones and cooling zones are arranged at intervals, the number of reaction zones and cooling zones is equal or differs by one, and there is no need to cool the raw materials before and after the reaction is completed. , so it doesn't make much sense to set the two regions at both ends of the remaining regions as cooling zones, so it's better to choose to reflect one more than the number of cooling zones.

Porous partitions divide the inner space of the shell into ring-shaped areas. The number can be arbitrary, but the more divisions, the more complex the system and the higher the cost. It is preferably divided into 11 areas, so that 5 reaction areas and 4 cooling areas can be obtained. district.

The present invention also provides a reaction device composed of the above-mentioned horizontal moving bed reactors connected in series, in parallel or in combination.

The horizontal moving bed reactor of the invention is simple in structure, easy in equipment design, manufacture and maintenance, convenient in operation, easy in controlling reaction progress and maintaining good reaction conditions.

The conversion of oxygen-containing compounds into propylene is an exothermic reaction. During the reaction, the temperature of the raw material will increase. Part of the raw material liquid can enter the cooling zone through the cooling liquid inlet to mix with high-temperature products to reduce the temperature of the raw material and improve the selectivity of the catalyst to propylene. At the same time, the heat of reaction is effectively utilized to further realize energy saving and consumption reduction.

The reactor can arrange multiple catalytic reaction zones horizontally, thereby reducing the thickness of a single reaction zone, reducing the temperature rise of the catalyst bed, and reducing the pressure drop of a single bed, so that the reaction can be carried out under more uniform and stable conditions.

Description of drawings

Figure 1 is a schematic structural view of the horizontal moving bed reactor of the present invention.

Detailed ways

As shown in Figure 1, a kind of horizontal moving bed reactor that is used to produce propylene with oxygen-containing compound as raw material, comprises a horizontal cylindrical casing 1, and the cross section of casing 1 also can be other shapes, as square , ellipse, trapezoid, etc. A raw material inlet 2 is provided at one lateral end of the housing 1 , and a product outlet 3 is provided at the other end.

Housing 1 is provided with 10 plane screens 8 horizontally arranged in parallel, and the screen 8 divides the internal space of the housing into 11 horizontally continuously arranged areas. It communicates with the product outlet 3, and the remaining 9 areas are 5 reaction areas 4 and 4 cooling areas 5, and the reaction areas 4 and cooling areas 5 are arranged at intervals. In addition to the screen 8, other partitions, such as perforated partitions, can also be used.

Because the catalyst flows continuously in the reaction zone 4, it will be worn by the screen cloth 8. Therefore, a porous baffle 9 is installed on the side of the screen 8 next to the reaction zone. The reactor is set up so that the catalyst particles cannot easily pass through without significant impact on the reactant fluid.

By increasing the number of screens 9, the number of reaction zones 4 and cooling zones 5 can be increased. The increase in the number of screens 8 will make the reactor more complicated, increase the manufacturing cost, and certainly increase the processing capacity of raw materials. Since the unreacted raw material and the complete product of the reaction do not need to be cooled, the quantity of the reaction zone 4 is preferably one more than the quantity of the cooling zone 5, and the reaction zone 4 and the cooling zone 5 are arranged at intervals, which will make the reaction The former raw material and the post-reaction product do not pass through the cooling zone 5 .

The housing 1 corresponding to the upper and lower ends of the reaction zone 4 is respectively provided with a catalyst inlet 6 and a catalyst outlet 7. The catalyst can flow continuously in the reaction zone 4 by its own weight. In order to further control the reaction temperature, a catalyst is added in the reaction zone 4. A heat exchange tube (not shown in the figure) is provided, and the heat exchange medium required for heat exchange can be methanol, water or a mixture thereof.

The housing 1 corresponding to the cooling zone 5 is provided with 8 coolant inlets, which communicate with the quenching liquid nozzle 10 located in the cooling zone 5, and of course, the number of coolant inlets can also be increased to increase the cooling capacity. The number of liquid nozzles 10 is generally increased to 64 when the diameter of the reactor is greater than 5m. The coolant sprayed from the quench liquid nozzle 10 can be selected from raw materials, water or other inert solvents, preferably a mixture of raw materials and water.

The two areas at the end of the shell 1 and the shell 1 where all the lower ends of the cooling zone 5 are located are provided with purge gas inlets 11, and the purge gas is selected from water vapor, methane or other inert gases. By introducing purge gas, liquid substances such as raw materials and cooling liquid are prevented from accumulating at the bottom of the shell 1, so as to achieve the purpose of continuous reaction.

The working principle of the above-mentioned horizontal moving bed reactor is as follows:

The raw material enters the shell from the raw material inlet 2, then diffuses along the lateral direction, and penetrates each screen 8 and porous baffle 9 respectively. The catalyst moves in the reaction zone 4 under the action of gravity, and the raw material will contact the catalyst during the diffusion process. The reaction produces the product propylene and other by-products. During the reaction process, a large amount of heat will be released, and the temperature of the raw materials will rise. When the raw materials enter the cooling zone 5, the cooling liquid will be sprayed through the quenching liquid nozzle 10 to mix with the reacted raw materials to reduce the temperature of the raw materials. Of course, since there are heat exchange tubes in the reaction zone 4, the reaction temperature can be controlled more precisely. The cooled raw material immediately enters the next reaction zone 4, so that the cycle continues. The final product flows out from the product outlet, and the product propylene is obtained through separation.

In order to achieve larger-scale production, multiple above-mentioned moving bed reactors can be connected in series, in parallel or in combination. A heat exchanger is added between two adjacent moving bed reactors, so that the reaction temperature of the next moving bed reactor is more suitable for converting propylene.

Claims (10)

1. One kind to be used for the oxygenatedchemicals be the horizontal moving bed reactor of raw material production propylene, comprise housing (1), the horizontal end of housing (1) is provided with material inlet (2), the other end is provided with product outlet (3), housing is provided with the porous spacing body in (1), it is characterized in that: described porous spacing body is separated at least 5 transversely arranged zones with housing (1) internal space, two zones that are positioned at housing (1) end are communicated with material inlet (2) and product outlet (3) respectively, reaction zone (4) and cooling zone (5) that all the other zones are provided with for the space; Be respectively equipped with catalyst inlet (6), catalyst outlet (7) on the pairing housing of reaction zone (4) upper/lower terminal (1), the pairing housing in cooling zone (5) (1) is provided with cooling liquid inlet.
2. 2. horizontal moving bed reactor according to claim 1 is characterized in that: described porous spacing body is at least 4 flat-surfaced screens that laterally are arranged in parallel (8).
3. 3. horizontal moving bed reactor according to claim 2 is characterized in that: the side of the adjacent reaction zone of described screen cloth (8) (4) is provided with perforated baffle (9).
4. 4. horizontal moving bed reactor according to claim 1 is characterized in that: be provided with the Quench nozzle for liquid (7) that is communicated with cooling liquid inlet in described cooling zone (4).
5. 5. horizontal moving bed reactor according to claim 4 is characterized in that: the described quantity of Quench nozzle for liquid (7) in single cooling zone (5) is 4～64.
6. 6. horizontal moving bed reactor according to claim 1 is characterized in that: described reaction zone is provided with heat transfer tube in (4).
7. 7. horizontal moving bed reactor according to claim 1 is characterized in that: described housing (1) is provided with the sweep gas import (11) that is communicated with two zones that are positioned at housing (1) end and lower end, cooling zone (4).
8. 8. horizontal moving bed reactor according to claim 1 is characterized in that: the total quantity of described reaction zone (4) and cooling zone (5) is an odd number, and reaction zone (4) quantity is Duoed one than cooling zone (5) quantity.
9. 9. horizontal moving bed reactor according to claim 1 and 2, it is characterized in that: described porous spacing body is separated into 11 zones with housing (1) internal space, wherein 5 zones are reaction zone (4), and 4 zones are cooling zone (5), and reaction zone (4) and cooling zone (5) are provided with at interval.
10. 10. reaction unit of forming by described horizontal moving bed reactor series, parallel of claim 1 or series-parallel connection.

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