JPS63252540A - Three-phase fluidized reaction apparatus - Google Patents

Abstract

PURPOSE:To enhance not only gas-liquid contact efficiency by improving the dispersion of supply gas but also economical efficiency by reducing the supply amount of gas, by providing a float pedestal in a bubble cap type dispersing device and inserting a float in said pedestal. CONSTITUTION:A float 24 is composed of a cone-shaped metal and the center thereof is arranged on the central axis of a float pedestal 5 and, when the float 24 is raised upwardly by the gas-liquid fluid mixture 23 flowing through a dispersing device 20, the fluid mixture 23 is allowed to pass through the narrow gap between the float 24 and the pedestal 25. The fluid mixture after passage is injected from a plurality of the jet nozzles 21 provided to the side surface of the upper part of the dispersing device 20 in the lateral direction and is bent in its flow downwardly by a catalyst shielding cylinder 28 to be again injected from the falling preventing cap 18 and a dispersing plate 4 in the lateral direction. By this method, the float 24 and the float pedestal 25 generate proper pressure drop to act in order to uniformize the dispersion of the gas.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a three-phase flow reactor for gas, liquid, and solid. ! ! This invention relates to a flow reactor equipped with a dispersion mechanism for gas and liquid at its lower part, which allows gas and liquid to flow upward.

[Conventional technology]

A three-phase flow reactor for gas, liquid, and solid has good contact efficiency among the three phases and good mixing inside the reactor, so it uses a gas expansion device, especially a catalyst, to generate a large amount of reaction heat. It is known to be effective against exothermic reaction systems.

An example thereof is a hydrodesulfurization reactor or a hydrocracking reactor that desulfurizes or decomposes heavy and medium fractions fractionated from crude oil in the presence of a catalyst while supplying hydrogen gas.

It is also a synthesis reaction apparatus for synthesizing methyl alcohol by supplying a mixed gas containing carbon oxide and hydrogen as main components into a mixture of a solvent and a catalyst.

The general flow state of a three-phase reactive flow device is as described in detail in Sakae Tanaka's "Chemical Engineering" Vol. 34, No. 12, p. 1265 (1970). To flow liquid and gas upward from the bottom of the container at a speed sufficient to fluidize solid particles such as catalysts filled to about 1/2 to 2/3 of the container and at a rate that does not cause the solid particles to rise along with the container. This results in the formation of a more stable fluidized bed of solid particles.

In order to achieve this fluid state, it is essential to extract the liquid from the upper part of the expanded catalyst layer and to circulate the liquid by using a pump to supply it to the lower part of the cylindrical container. This is done in order to maintain the liquid flow rate required for catalyst fluidization through circulation.

Further, to explain in more detail a specific example using this three-phase fluidized reactor, when performing hydrodesulfurization of petroleum type and medium distillates, 9/c! n”G, 350~4
A hydrogenation reaction is carried out by bringing the supplied oil and gaseous hydrogen into contact with a 15 to 2-φ cylindrical or spherical nickel-molybdenum, cobalt-molybdenum, or tungsten-molybdenum catalyst under 00°C conditions. achieved.

FIG. 4 shows the structure of a typical conventional three-phase fluidized reactor. The inside of the reactor body 1 is filled with a catalyst, and the upper surface 2 of the catalyst layer 17 is fluidized by the upward flow of liquid and gas, and expands to the upper surface 3 of the expanded catalyst layer 17. A dispersion plate 4 is provided at the bottom of the catalyst layer 17 to improve the dispersion of gas and liquid supplied from the bottom and to prevent the catalyst from accumulating at the bottom of the container. The supply gas 5 is supplied separately from the circulating liquid 7 from the lower part of the reactor main body 1, passes through the distribution plate 4, and reacts while passing through the catalyst layer 17. After passing through the catalyst layer 17, the gas and liquid pass through a clarification layer 8 for separating the catalyst, and the reaction product liquid, which is a part of the reaction gas and reaction liquid, is discharged from the extraction pipe 9 at the top of the reactor body 1. being extracted. Most of the reaction liquid 6 is transferred to the suction section 10 and the suction tube 11
The liquid is extracted from the liquid supply pipe 16 and circulated as a circulating liquid 7 to the reactor main body 1 via a pump (not shown).

[Problem that the invention seeks to solve]

In the above-mentioned reactor, if the supplied gas is not sufficiently dispersed, the gas-liquid contact efficiency will deteriorate, and an extremely excessive amount of gas must be used to dissolve the amount of gas necessary for the reaction into the liquid. It is necessary to supply the gas and liquid to ensure the gas-liquid contact interface area. If this happens, the power of the gas compressor for supplying the gas to the high-pressure reaction system will increase, and the equipment for the gas supply system will also become larger.

In addition, if gas dispersion is uneven, there is a risk that the reaction will occur at uneven locations, causing problems such as uneven reaction temperature distribution and abnormal reactions. It is essential that the limits are uniform.

From this point of view, various dispersion means have been proposed in the past.

FIG. 5 is an example of the dispersion device used in the three-phase fluidized reactor shown in FIG.

In FIG. 5, the circulating fluid 7 passes through the liquid supply pipe 16 to the collision plate 1.
After colliding with 2, the Denam Champer 27 at the bottom of the reactor main body 1
The gas rises inside the distributor 20, is supplied together with the supply gas 5 through one or more slits 14 provided at the bottom of the distributor 20, flows into the catalyst layer 17, and expands the catalyst layer 17 to a certain height.

The above-mentioned disperser 20 is used to help disperse the liquid and the supplied gas, and has a shape similar to a pub μ cap often used in distillation columns, for example, and has a jet nozzle on the upper side of the disperser 20. A plurality of (openings) 21 are provided in the dispersion plate 4 .

However, this shape of the disperser 20 has a small flow pressure loss during the flow of supply gas and liquid.
Slight fluctuations in the gas-liquid interface 15 formed within the disperser 7 greatly affect the amount of supply gas supplied to each disperser 20 . That is, as shown in FIG. 6, which is a partial enlargement of FIG. 5,
When the gas-liquid interface 15 fluctuates downward near the slit 14a of the disperser 20a, the supply gas 5 flows in through the slit 14a, but it does not flow in at all in the other slit 14t), and the fluctuation in the gas-liquid interface 15 causes the supply gas to This will have a significant impact on the dispersion of

Furthermore, although the catalyst drop prevention cap 18 is provided on the disperser 20 to prevent the catalyst layer 17 from falling into the plenum chamber 27, when the reactor is stopped, It is difficult to say that it is possible to completely prevent the catalyst from falling. These catalyst particles enter the plenum chamber 27.
If it enters a pump (not shown) through this process, it will cause a pump failure and cause a great deal of trouble in the operation of the three-phase fluidized bed.

In addition, a dispersion device shown in FIG. 7 (4) CB) has been proposed to improve the low pressure loss and prevention of falling of the catalyst, which are the drawbacks of the bubble cap-like dispersion device 20. In this device, a gas-liquid multiphase fluid 25 is dispersed into the catalyst layer from the jet nozzle 21 while pushing aside a dispersion plate 19 attached in place of the dispersion cap 18.

As shown in Fig. 03), which is a plan view of the dispersion plate 19 portion, the ejection nozzles 71/21 penetrate around the disperser 20 in the same shape, for example, in the direction, and the outer end thereof is connected to the sea μ
The valve seat structure is designed for the purpose of Further, the dispersion plate 19 has a flexible integral structure, and has a valve structure that closes each side of the jet nozzle/I/21 to prevent backflow from the outside. The distribution plate 19 is fixed to the upper part of the distributor 20 by a fixing port 22.

Due to the inflow of the gas-liquid multiphase fluid 23, this distribution plate 19
is pushed away and dispersed into the fluidized bed through the jet nozzle /I/21. The dispersion plate 19 has a kind of spring structure, and when the inflow of fluid is stopped, the dispersion plate 19 comes into close contact with the valve seat of the jet nozzle fi/21 again, and prevents mainly the catalyst particles in the fluidized bed from entering the dispersion device 20. It plays a role in preventing

In the dispersion state, the dispersion plate 19 exhibits a vibrating shape during so-called fluid jetting, which causes the dispersion plate 19 to vibrate in small increments, cutting the gas-liquid into small pieces.In particular, the gas is made into cells, and it is said that a good dispersion state is achieved. There is.

Therefore, the uniformity of the strength of the dispersion plate 19 is very strictly required, and not only when there is one dispersion plate, but also when there is a plurality of dispersion plates,
In an actual commercial machine, there may be hundreds of pieces, making it virtually impossible to control the quality of the dispersed plate 19, and causing fatigue fracture due to the rounding of the dispersed plate 19 as it vibrates under high temperatures. is also pointed out.

In the unlikely event that the dispersion plate 19 suffers fatigue failure, a large amount of gas will flow into the catalyst layer from the fatigue failure point, and an abnormal reaction will occur at the gas inlet, creating a very dangerous situation. Prevention of fatigue failure is essential. In order to prevent fatigue failure, we have focused on how to control and improve the durability and reliability of the dispersion plate 15'.In addition to regular inspections, we also need to round the dispersion plate 15' in preparation for unexpected situations. It becomes necessary to replace all the plates 19, which is impractical from the viewpoint of construction work.

The present invention solves all the problems seen in the conventional dispersion means as described above, improves the dispersion of the supplied gas, increases the gas-liquid contact efficiency, and improves economic efficiency by reducing the amount of supplied gas. This paper proposes a three-phase flow reactor equipped with a dispersion mechanism that allows for

[Means for solving problems]

The present invention solves the above-mentioned problems by providing a float pedestal in a Pub μ-cap type disperser and inserting a float into the pedestal.

That is, in the present invention, a plate is provided for mounting a dispersion cylinder in which a large number of dispersion cylinders are installed in the lower part of a three-phase fluid reaction apparatus main body, and the dispersion cylinder is mounted from a gas-liquid mixed layer in the lower layer of the plate to a solid particle layer in the upper layer. In a three-phase fluidized bed reactor that fluidizes the solid particle layer by guiding a gas-liquid mixed phase fluid through a cylinder, a float pedestal is provided inside the dispersion cylinder, and the axis of the float pedestal is made equal to the axis. A float is installed on the float pedestal, one or more openings are provided at the top of the dispersion cylinder, and the top of the dispersion cylinder has an inner diameter that is aligned with the axis of the dispersion cylinder and that is larger than the outer diameter of the dispersion cylinder. The present invention relates to a three-phase flow reactor, characterized in that a catalyst shielding cylinder having a sealed upper end is installed with a gap between the distributor and the plate.

[Examples and effects]

FIG. 1 is a diagram showing an example of a dispersion mechanism according to the apparatus of the present invention.

In FIG. 1, the same reference numerals as in FIGS. 4-7 indicate the same parts as in FIGS. 4-7.

In FIG. 1, a float pedestal 25 and a float 24 are inserted into the pedestal 25 in a pub μ-cap type disperser (dispersion cylinder) 20.

The float 24 is made of conical metal, and its center axis is placed on the center axis of the float pedestal 25.
The gas-liquid multiphase fluid 23 flowing through the disperser 20 lifts the gas-liquid multiphase fluid 23 upward, and after passing through the narrow gap between the float 24 and the float pedestal 25, the gas-liquid multiphase fluid 23 passes through the narrow gap between the float 24 and the float pedestal 25. It is ejected from the I/(opening) 21 in the direction of the shell, and the catalyst prevention cap (catalyst shielding cylinder) 18
After the flow is bent downward, it is ejected laterally again from the narrow gap between the catalyst prevention cap 18 and the dispersion plate (the dispersion cylinder is attached to a plate) 4. It is preferable that this gap is slightly smaller than the diameter of the catalyst particles used in the three-phase fluidized bed in order to prevent backflow of the catalyst particles into the plenum chamber 27.

In addition, since the float 24 in the present invention causes a pressure loss when the gas-liquid multiphase fluid 23 flows in due to its own weight,
Not only can the gas be uniformly dispersed, but also in the event of an operational stop, this float 24 is set on the float pedestal 25, which prevents catalyst particles from entering the plenum chamber 27 due to backflow of fluid. be able to.

Furthermore, the dispersion mechanism in the present invention is similar to the Pub μ cap used in ordinary distillation columns, and the float 24 and float pedestal 25 can be easily machined and replaced.

Further, the shape of the float 24 is not limited to the conical shape shown in FIG. 1, but can be changed to a spherical shape, a cylindrical shape, etc. depending on the purpose. Among them, in the case of cylindrical floats, the second country and its A-
As shown in FIG. 2 CB), which is a cross-sectional view taken along the line A, the lower part is tapered, and the float is arranged so that the axis of the float pedestal 25 and the axis of the cylindrical float 24 are aligned on the same axis. A guide 26 is provided.

Due to the dispersion mechanism of the present invention as described above, the dispersibility of gas and liquid is significantly improved, and the dispersibility of solid particles in the plenum chamber 2 is improved.
7 can be prevented from falling.

Next, specific examples according to the present invention and comparative examples using conventional ones will be given to concretely demonstrate the effects of the present invention.

Comparative Example 1 The performance of the conventional method was confirmed using a plastic cold flow model having the shape shown in FIGS. 4 and 5. The reactor body 1 has an inner diameter of 500 mm and a height of 3000 ms.

The dispersion device has a diameter of the disperser 20 of 50+m, a jet nozzle/I/
The cap 21 has a 13×29- oval shape at four locations around the circumference, the diameter of the cap 1B is 75 m, and the gap between the cap 18 and the dispersion plate 4 is 2 m. Four such dispersers 20 were attached.

White kerosene according to JI8 standards was used as the feed liquid, nitrogen was used as the gas, and an extrusion molded product with an apparent specific gravity of 1.55 and a diameter of t5cm and a length of about 5cm was used as the catalyst. The operating temperature is normal temperature and the operating pressure is normal pressure. The gas was supplied at a superficial velocity of 4 cs/sec. In addition, the liquid has a superficial velocity of 1 to 10 ty
It was supplied in the range of m/see.

Tests were conducted under these conditions to determine the amount of gas retained (gas hole μ).
When measuring the amount of air bubbles (door bubbles), it was found that the concentration was 12 to 15 vol %, ibb, and many large bubbles with diameters exceeding several liters were observed.

In addition, infiltration of the catalyst into the disperser 20 was also observed, especially when the liquid
When the gas was turned off, a large number of catalysts entered the system, causing uneven flow during recirculation.

Comparative Example 2 The disperser of the test device described in Comparative Example 1 was used in the 7th country (Russia).
The same test as in Comparative Example 1 was conducted using the disperser shown in FIG.

As the dispersion plate 19, a stainless steel plate with a thickness of CL2 and α4 was used.

Under this condition, the amount of gas retained at the distribution plate 1
9 thickness L2■, Q, 4■ 25 vo
1%, there were almost no bubbles larger than a few centimeters in diameter, and the entire structure was occupied by fine bubbles, clearly improving the dispersion effect and improving the gas-liquid contact efficiency.

In addition, backflow and intrusion of the catalyst were completely prevented, but in an experiment using the dispersion plate 19 made of a stainless steel plate with a thickness of 2 mm, the operation was carried out for 2000 hours, and after the end of the operation, the dispersion plate V-)19
A crack was found around one of the fixing bolts 22, so we inspected all the other dispersion plates 19 and found that there were hair cracks in 5 of the plates 2cm thick and 2 of the plates 14mm thick. mud was discovered and it was determined that there was a problem with its durability.

EXAMPLE OF THE INVENTION The disperser shown in Comparative Example 1.2 was changed to the dispersion mechanism according to the present invention shown in FIG. 1, and the same test as in Comparative Example 1.2 was conducted. The dimensions of the main parts are as shown in Figure 3 CB).The 5th country is for the whole, and Figure 3) is for the float pedestal 25.
(unit: m), and 5VS504 was used as the material for the float 24.

Under these conditions, the amount of gas retained was 25 vol, and the diameter of the bubbles was also very small.

In addition, the gas distribution was also very uniform. 2000 hours,
After 5,000 hours of operation, no abnormality was found in the open inspection after the end of operation, confirming the superiority of the present invention.

〔Effect of the invention〕

According to the device of the present invention, the float of the dispersion mechanism and the float pedestal provided at the bottom of the phase fluidized bed reactor main body generate an appropriate pressure loss, uniformly dispersing the gas, and achieving high air flow with a small amount of gas. Liquid contact efficiency can be obtained.

Furthermore, problems such as fatigue failure of the members of the dispersion mechanism are eliminated, and the complexity of quality control and the risk of abnormal reactions are also eliminated.

[Brief explanation of drawings]

Fig. 1 is a diagram showing an example of the dispersion mechanism according to the present invention, and Fig. 2 is a diagram showing another example of the dispersion mechanism according to the present invention.
) in Figure 2 is a cross-sectional view taken along the line A-A in Figure 2), Figure 3) is a diagram showing the dimensions of the main components of the dispersion mechanism used in the specific example of the present invention, and Figure 4 is A diagram showing a general three-phase fluidized bed reactor, Figure t45 is a diagram showing a conventional dispersion equipment, Figure 6 is a partially enlarged view of Figure 5, and Figure 7) is a diagram showing another conventional dispersion equipment. 7(CB) is a plan view of a portion of FIG. 7(G). 1: Reactor body 2: Catalyst layer height when stationary 3: Catalyst layer height when boiling 4: Dispersion plate 5: Supply gas 6: Reaction liquid 7: Circulating liquid 8: Clarifying layer 9: Reaction gas and reaction liquid slope pipe 10: Suction part 11: Suction pipe 12: Collision plate 14 Nislit 15: Gas-liquid interface 16: Supply pipe 17: Catalyst layer 18: Catalyst fall prevention cap 19: Dispersion plate 20: Dispersion device 21: Ejection nozzle μ 22: Fixing bolt 25: Gas-liquid mixed phase fluid 24: Float 25: Float pedestal 26: Float guide 27: Punam Champa Figure 2 (A) Figure 3 (A) Figure 4 Figure 7 L B

Claims (1)

[Claims] A dispersion cylinder mounting plate with a large number of dispersion cylinders installed is provided at the bottom of the main body of the three-phase flow reactor, and the gas-liquid mixed phase is passed from the gas-liquid mixed layer at the bottom of the mounting plate to the solid particle layer at the upper layer via the dispersion cylinders. In a three-phase fluidized bed reactor that fluidizes the solid particle layer by guiding a fluid, a float pedestal is provided inside the dispersion cylinder, and a float whose axis is equal to the axis of the float pedestal is mounted on the float pedestal. a catalyst shield having one or more openings at the top of the dispersion cylinder, the top of the dispersion cylinder having the same axis as the dispersion cylinder and having an inner diameter larger than the outer diameter of the dispersion cylinder and sealing the upper end thereof; A three-phase fluid reaction device, characterized in that the cylinder is installed with a gap between it and the distributor mounting plate.