RU195804U1 - DEVICE FOR CARRYING OUT CATALYTIC PROCESSES IN THREE-PHASE SUSPENSION LAYER - Google Patents

Abstract

The utility model relates to apparatuses of the chemical and petrochemical industry and is intended for carrying out mass transfer processes in a system of suspension catalysis reactors and can be used, in particular, for carrying out the Fischer-Tropsch synthesis reaction in suspension reactors. The device for carrying out catalytic processes in a three-phase suspension layer includes a bubbling a column filled with a suspension of a nanosized catalyst in the liquid phase, a circulation line, a pipe for introducing the liquid phase into the column h Through a circulation line, an ejector for introducing a gas phase mounted at the bottom of the bubble column and connected to a gas phase inlet line and a circulation line, and a pipe for outputting reaction products. The circulation line is connected to the column through an overflow jumper with the possibility of overflow of the liquid phase. The ejector includes a housing with an expansion nozzle, a replaceable nozzle and a chamber for mixing liquid and gas phases located inside the housing between the nozzle and nozzle, to which nozzles for introducing these phases are connected. The ratio of the nozzle diameter to the inner diameter of the nozzle is 1:10, and the inner diameter of the nozzle and the diameter of the nozzle for introducing the liquid phase from the circulation line are approximately equal. Technical result: efficient circulation of the liquid phase from the circulation line to the bubble column without using a pump and other suction or injection devices. 1 table, 2 ill., 5 ave.

Description

The utility model relates to apparatuses of the chemical and petrochemical industry and is intended for carrying out mass transfer processes in a system of slurry catalysis reactors and can be used, in particular, for carrying out the Fischer-Tropsch synthesis reaction in slurry reactors.

Bubbling suspension reactors (in the English literature - slurry bubble column reactor, SBR) and bubbling bed reactors (ebullated bed reactor, EBR) are widely known. Both types of reactors are hollow vessels filled with a suspension catalyst layer, in which gas in one mode or another sparges and differs primarily in the size of the particles used - tens of microns for the first type and about 1 millimeter for the second.

Existing bubble reactors for the implementation of three-phase suspension processes are distinguished by the following important structural components:

a) gas distribution device (dispersant) - a horizontal plate with holes located at the base of the column. With all the possible variations in the design of the holes, the purpose of this device is to ensure the formation of a bubble stream with the smallest and most uniform bubbles, which promotes intensive mixing of the liquid medium with the catalyst particles contained in it and mass transfer between the latter and the gas flow, which is important for the effective implementation of catalytic processes of the named type. Also, this device should be selected so as to exclude a failure (by a known analogy with distillation column plates) of the liquid phase directly into the supplied gas stream;

b) a circulation line parallel to the main column, if for one reason or another it is necessary to ensure the flow regime of the reactor and the suspension. The circulation is ensured by the installation of a pump of one design or another (because, when it comes to syntheses from CO and H ₂ , the conditions for the occurrence of developed movement in the gas lift mode are practically unrealizable); in addition to circulation, the catalytic suspension in this line can undergo other operations (removal of spent / supply of fresh suspension, etc.).

A device for producing a catalyst suspension is known, including a housing, nozzles for introducing the starting components and the finished product, a vertical paddle low-speed mixing device, on each blade of which two paddle elements are fixed, and a lateral high-speed mixing device in the form of disk activators (see. USSR 1775148 A1, IPC B01F 7/00, publ. 11/15/1992).

A disadvantage of the known device is the complexity of the design and the high cost of manufacture.

A device for producing a suspension of a catalyst is known, including a pipeline with ferromagnetic elements located in a rotating electromagnetic field of a generator - stator of a three-phase AC machine. The components of the suspension are mixed under the action of torque and magnetic field irregularities. The mixed and dispersed components of the suspension are discharged through a grating that protects the ferromagnetic elements of the device from removal (AS USSR 567481, IPC B01F 13/08, publ. 08/22/1977).

The disadvantages of the known device are the heating of the catalyst particles from eddy currents at an uncontrolled heating temperature, high energy consumption and lack of recirculation.

The closest to the claimed by the set of essential features and achieved technical result (prototype) is a device for carrying out catalytic processes, namely, Fischer-Tropsch synthesis, in a three-phase suspension layer in suspension reactors, including a bubbler column filled with a suspension of a nanoscale catalyst in a liquid phase, a pipe for entering the liquid phase, the device for entering the gas phase into the column is a perforated dispersant, mounted at the bottom of the bubble column and connected with a line input of the gas phase, a circulation line connected to the column via an overflow jumpers, with overflow of the liquid phase, an ejector for the circulation of the liquid phase and outlet for the withdrawal of the reaction products. (M.V. Kulikova, A.E. Kuzmin, and O.B. Chupichev, “Field simulation of bubbling in a Fischer-Tropsch synthesis reactor with a nanoscale catalyst,” Journal of Applied Chemistry. 2018.V. 91. Issue 4, p. 528-532)

The device allows to ensure the optimal size of the synthesis gas bubbles passing through the suspension catalyst layer, effective mixing and saturation of the suspension medium with reagents due to intensive bubbling, and as a result, provides a high conversion of raw materials and high yield of reaction products.

The disadvantage of the described device is the almost complete absence of circulation of the suspension in the device, which affects the efficiency of use of the catalyst.

The objective of the utility model is to develop a device for carrying out catalytic processes in a three-phase suspension catalyst bed, which provides effective dispersion of the bubbling gas and circulation of the liquid phase in the absence of the use of pumps or other suction or discharge devices at the same time.

The problem is solved by the fact that a device for carrying out catalytic processes in a three-phase suspension layer is proposed, including a bubble column filled with a suspension of a nanoscale catalyst in the liquid phase, a circulation line connected to the column through an overflow jumper with the possibility of overflowing the liquid phase, a pipe for introducing the liquid phase into the column through the circulation line, a device for entering the gas phase, mounted at the bottom of the bubble column and connected to the line of input of the gas phase and a circulation line, and a pipe for outputting reaction products, in which the device for introducing a gas phase is an ejector including a housing with an expansion nozzle, a replaceable nozzle, and a liquid and gas phase mixing chamber, to which the nozzles are connected, located inside the housing between the nozzle and the nozzle for entering the liquid and gas phases, the ratio of the diameter of the nozzle and the inner diameter of the nozzle being 1:10, and the inner diameter of the nozzle and the diameter of the nozzle for entering the liquid phase from the circulation line are approximately equal.

The technical result of the use of the implementation of the circulation of the liquid phase from the circulation line to the bubble column without the use of a pump and other suction or discharge devices.

The proposed model is presented in FIG. 1 where

1 - ejector

2 - bubble column

3 - circulation line

4 - gas phase input line

5 - pipe for the initial filling of the bubble column with a liquid phase and gas outlet.

6 - overflow jumper.

The device consists of: a bubble column (2) connected to a circulation line (3) and a gas phase input line (4) through an ejector (1) made of stainless steel 12x18n10t) located at the bottom of the bubble column and also connected to the circulation line through an overflow line the jumper (6) located in the upper part of the device. At the top of the column (2) and the circulation line (3), a nozzle (5) is installed, which serves both for the initial filling of the device with a liquid phase and for gas outlet from the device.

In FIG. 2 presents the design features of the ejector in the context:

7 - replaceable nozzle

8 - pipe input gas phase (ejection medium)

9 - pipe input liquid phase (ejected medium)

10 - ejector housing with an expansion nozzle and an internal chamber for mixing liquid and gas phases

The ejector is structurally constructed according to the classical scheme and consists of a housing with an expansion nozzle and an internal chamber for mixing liquid and gas phases (10), in which a gas-liquid flow is formed and ejected into the bubble column (2), a replaceable nozzle (7), and an input line for the ejection medium ( 8), into which the gas phase enters, the input lines of the ejected medium (9), into which the liquid phase enters (catalyst suspension).

The proposed utility model is made in glass for the possibility of visual control of the hydrodynamic situation (bubble sizes, turbulent phenomena, piston formation, etc.) using 12x18n10t stainless steel shut-off fittings and is intended for carrying out catalytic processes in a three-phase suspension layer and can be used in carrying out processes using vapor-gas bubbling in suspensions containing nanosized catalyst particles, in particular, during the synthesis reaction for Fischer-Tropsch in slurry reactors.

The utility model works as follows:

The suspension (liquid phase) (total volume of about 2.5 l) is loaded into the device through the pipe (5) at the top of the bubble column (2) to the level of the overflow bridge (6) either slightly higher or slightly lower. The gas phase is supplied - the raw material of the corresponding catalytic processes (overpressure up to 2 atm), with the calculated volumetric flow rate into the inlet of the ejector medium (8) of the ejector (1). The gas phase leaves the nozzle (7) into the expansion nozzle (10) of the ejector (1) and then into the volume of the bubble column (2), dragging the liquid phase along through the liquid phase inlet line (9), where it enters from the circulation line (3 ) After bubbling in the column (2), the gas (gas phase) leaves the volume of the suspension layer and then is removed from the device through the pipe (5). The liquid phase from the column (2) constantly flows through the overflow bridge (6) to the circulation line (3), from where it is again ejected into the column, thus closing the circulation circuit.

The volumetric flow rate of the liquid phase is controlled by varying the gas flow rate (within the limits determined by the limitations of the simulated process).

The following example illustrates the operation of the proposed utility model.

Examples 1-5.

Tests of the proposed device are carried out using hexane, whose properties simulate a Fischer-Tropsch suspension synthesis medium (molten paraffin in which the catalyst is suspended) under real conditions of this process. Nitrogen is used as the gas phase, whose properties simulate synthesis gas under real Fischer-Tropsch synthesis conditions.

A gas phase with a flow rate of 25 l / h, 50 l / h, 75 l / h, 100 l / h and 125 l / h, respectively, is fed into the reactor with the loading of the catalytic suspension (liquid phase) up to 2.5 liters. Create excessive gas pressure on the ejector up to 2 atm.

The test results are shown in the table, demonstrating the degree of circulation of the liquid phase while bubbling.

Thus, a design of a device for carrying out catalytic processes in a suspension catalyst bed is proposed, devoid of the disadvantages of both the prototype and known reactors having a gas dispersant in the base of the reactor and a pump in the line of the circulating suspension. The use of the proposed device with an ejector as a device for introducing a gas phase causes a high degree of circulation without the use of pressure or pumping devices, such as a pump.

Claims (1)

A device for carrying out catalytic processes in a three-phase suspension layer, including a bubble column filled with a suspension of a nanoscale catalyst in the liquid phase, a circulation line connected to the column through an overflow jumper with the possibility of overflow of the liquid phase, a pipe for introducing the liquid phase into the column through the circulation line, a device for the input of the gas phase, mounted at the bottom of the bubble column and connected to the input line of the gas phase and the circulation line, and a pipe for outputting reaction products, characterized in that the device for introducing a gas phase is an ejector including a housing with an expansion nozzle, a replaceable nozzle and a chamber for mixing the liquid and gas phases located between the nozzle and the nozzle, to which the nozzles for introducing the liquid and gas phases are connected, moreover, the ratio of the diameter of the nozzle and the inner diameter of the nozzle is 1:10, and the inner diameter of the nozzle and the diameter of the nozzle for introducing the liquid phase from the circulation line are approximately equal.

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