JP2003002906A - Method for feeding powdery catalyst - Google Patents

Abstract

PROBLEM TO BE SOLVED: To minimize an amount of associated fluid to feed intermittently a powdery catalyst to a reactor while changing continuously or uniform by the concentration of the powdery catalyst which discontinuously exists in the associated fluid, from a catalyst feeder. SOLUTION: This method for feeding the powdery catalyst to the reactor while making the concentration of the powdery catalyst uniform to the flow direction has a means for temporarily retaining the flow of the powdery catalyst which intermittently flows accompanied by the fluid in the course of the flow path.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a catalyst feed method for feeding powdered catalysts to gas phase or liquid phase reactors, particularly preferably gas phase fluidized bed and gas phase stirred bed reactors.

[0002]

2. Description of the Related Art When a powdery catalyst is supplied to a reactor, a method of using an appropriate inert fluid as a transporting fluid for the powdery catalyst and entraining the powdery catalyst in this fluid is often adopted.
As a fluid used for entraining the catalyst (sometimes referred to as an entrained fluid), an inert fluid is usually used in both cases of liquid and gas. Here, since the entrained fluid inevitably flows into the reactor together with the catalyst, when an inert fluid is used, it is necessary to discharge the inert fluid from the reactor when the supply amount is large. At this time, normally, unreacted substances and the like are also released together with the released fluid, and it is difficult to completely recover them, which causes a loss.
Further, even if the catalyst supply system is simply increased in order to increase the catalyst supply rate to the reactor, the inflow amount of the inert fluid into the reactor increases as described above, so that the loss also increases. Therefore, in either case, the amount of inert fluid flowing into the reactor should be minimized.

Further, the supply of the powdery catalyst will be described with reference to an example of an olefin gas phase polymerization reactor. When the catalyst is intermittently supplied from one series of catalyst supply nozzles, the amount of the catalyst supplied is preferably an amount that can be sufficiently dispersed after being supplied to the reactor. That is, when too much catalyst is supplied at one time, the polymerization proceeds before the catalyst is sufficiently dispersed, which causes formation of a lump polymer. Not only does this bulk polymer reduce the yield of polyolefin formed, but itself or the less catalytically effective solid catalyst present therein causes gels in the product. In the case of a gas phase fluidized bed reactor, the powdered catalyst fed into the reactor reaches the inner wall of the reactor without being sufficiently dispersed in the reactor, and if it adheres to it, it may cause the occurrence of sheeting on the wall surface of the reactor. . The degree of dispersion required for the catalyst also changes depending on the initial activity of the catalyst. That is, it takes time for the polymerization reaction to occur after being supplied to the reactor,
In the case of a catalyst having a so-called induction period, the catalyst is stirred and dispersed in the reactor during the induction period, so that even if more catalyst is supplied per unit time, a lump polymer is not produced. A catalyst that exhibits a polymerization activity only when it comes into contact with a cocatalyst can be considered in the same manner as a catalyst that has the above induction period because the contact usually occurs in the reactor. In the case of a catalyst having such an induction period, the amount of supplied catalyst can be made relatively large. On the other hand, in the case of a catalyst which does not have the induction period as described above, or in which the cocatalyst is already combined even though the cocatalyst is required, it is supplied to activate the activity immediately after being charged into the reactor. It is desirable to use a relatively small amount of catalyst. The amount of catalyst that can be supplied within a unit time varies because the degree of dispersion of the catalyst varies depending on the state in the reactor, for example, the fluidized state in the fluidized bed. Furthermore (catalyst / entrained fluid), ie (solid /
It also changes depending on the ratio represented by (fluid).

As described above, in order to prevent the formation of agglomerated polymers and the like, it is desirable to suppress the fluctuation of the catalyst concentration when supplying the powdery catalyst with time as much as possible. As one of the methods for reducing the fluctuation of the catalyst supply rate with time, there is a method of continuously supplying the catalyst into the entrained fluid at a constant rate and causing the entrained fluid to flow at a constant rate. However, gas phase polymerization is under relatively high pressure, and in order to supply the powdery catalyst to such a high pressure region, the pressure of the entrained fluid has to be higher, so that it is continuous with the fluid under high pressure. It is difficult to supply the powdery catalyst in a stable and quantitative manner. Therefore, generally, a method is used in which a certain amount of powdery catalyst is weighed by a catalyst weighing device and is intermittently entrained in a fluid. Therefore, it is difficult to continuously supply the entrained fluid to the entrained fluid while shortening the interval of metering and feeding the catalyst, and as a result, the powdery catalyst is entrained in the fluid intermittently or intermittently.

Japanese Unexamined Patent Publication (Kokai) No. 4-80206 proposes a method of reducing the cross-sectional area of the catalyst supply pipe in the horizontal direction halfway in order to continuously supply the catalyst entrained in the fluid to the reactor. To do. This is because the solid catalyst settled in the pipe due to the slow entrained gas flow in the horizontal catalyst supply pipe reduces the cross-sectional area of the catalyst supply pipe to increase the gas flow velocity, resulting in the dispersion of the solid catalyst particles. It is to improve the degree. This method is a method of preventing catalyst settling that occurs because the gas flow speed is reduced by reducing the amount of entrained gas.Although it is possible to reduce the amount of entrained gas, there is a limit to that, and the degree of catalyst dispersion is not always required. Not enough.
Further, the method described in JP-A-11-80256 is
It is a method of homogenizing the catalyst by fluidizing the solid catalyst that is intermittently supplied by the transport gas, but since it is diluted and fluidized by the high-speed transport gas, a large amount of transport gas is inevitably required, and Since this transport gas is supplied into the reactor, the loss is increased as described above, which is not preferable. In addition, Japanese Patent Laid-Open No. 60-227824 discloses a catalyst supply device in which an intermediate chamber is provided directly below the catalyst measuring device. A supply pipe for entrained fluid is connected to the intermediate chamber,
The powdery catalyst introduced into the intermediate chamber is entrained in the entraining fluid in the intermediate chamber. The catalyst powder, which is compressed into a certain lump during measurement, is unraveled when it falls in the intermediate chamber, and the compactness is reduced.

[0006]

DISCLOSURE OF THE INVENTION According to the present invention, as described above, the powdery catalyst is metered in intermittently or intermittently, and is entrained in the reactor when entrained in the fluid and fed to the reactor. It is an object to minimize the amount of the accompanying fluid and to make the concentration distribution of the powdery catalyst which flows discontinuously continuous or uniform.

[0007]

That is, the first aspect of the present invention
Is provided with means for temporarily accumulating the flow of the powdery catalyst flowing in the flow path intermittently or discontinuously along with the fluid, so that the concentration of the powdery catalyst is flowed. The present invention relates to a method for supplying a powdery catalyst, which is characterized in that the powdery catalyst is uniformly supplied to the reactor. A second aspect of the present invention relates to the method for supplying a powdery catalyst according to the first aspect of the present invention, wherein the flow direction of the powdery catalyst in the staying means is substantially vertically upward. A third aspect of the present invention relates to the method for supplying a powdery catalyst according to the first aspect of the present invention, wherein the staying means increases the cross-sectional area of the flow channel. The fourth aspect of the present invention is
In the third aspect of the present invention, the increase in the cross-sectional area of the flow channel is 1
The present invention relates to a method for supplying a powdery catalyst having a ratio of 00% or more.
A fifth aspect of the present invention relates to the method for supplying a powdery catalyst according to the first aspect of the present invention, characterized in that, in the staying means, the powdery catalyst is substantially fluidized by a fluid accompanying the powdery catalyst.
A sixth aspect of the present invention relates to the method for supplying a powdery catalyst according to the first aspect of the present invention, wherein a plurality of the retention means are provided in the middle of the flow path. A seventh aspect of the present invention relates to the method for supplying a powdery catalyst according to the third or fourth aspect of the present invention, which has a structure in which the cross-sectional area of the retaining means is once increased and then decreased again. An eighth aspect of the present invention relates to the method for supplying the powdery catalyst according to the first aspect of the present invention, wherein the powdery catalyst is a gas phase polymerization catalyst. A ninth aspect of the present invention relates to the method for supplying a powdery catalyst according to the eighth aspect of the present invention, wherein the vapor phase polymerization is olefin polymerization. The tenth aspect of the present invention is the eighth aspect of the present invention.
In the above, the gas phase polymerization relates to a method for supplying a powdery catalyst using a fluidized bed and / or a stirred bed reactor.

According to the present invention, for example, a container having a constant volume, such as a container having a constant volume, is provided in the middle of the flow path through which the powdery catalyst is supplied from the catalyst meter to the reactor.
By providing a room or the like, it is possible to reduce the temporal change in the concentration of the powdery catalyst supplied intermittently or intermittently, that is, to make the concentration of the powdery catalyst uniform in the flow direction. As a result, it was based on the finding that the powdery catalyst can be continuously supplied to the reactor. It was supplied intermittently or intermittently from the catalyst meter, so that the flow of powdered catalyst, which was discontinuous in the entrained fluid, was placed in the flow path between the catalyst meter and the reactor. This is achieved by temporarily retaining by the retaining means. In addition, when the retention means makes the flow path itself into a container or room-like shape, the maximum supply per unit time can be varied depending on the catalyst by selecting the inner diameter and the distance from the fluid inlet to the outlet. You can easily approach speed. That is, by changing the shapes of the container, the room, and the like, it is possible to easily adjust the catalyst supply rate that does not fluctuate with time.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in more detail below. (Powdered catalyst) The powdered catalyst may be a powdered material of any type of solid catalyst. For example, it may be a powdery catalyst used in a liquid phase or a gas phase reaction. However, powdered solid catalysts used for reactions in gas phase fluidized bed or gas phase stirred bed reactors are preferred. It may be in the form of being supported on an appropriate carrier as necessary. The particle size of the powdery catalyst is not particularly limited, but in the case of the olefin gas phase polymerization catalyst described later, for example, the average particle size is in the range of 1 to 500 μm. The powdery catalyst is used by sieving in a certain particle size range, but it is rare that the particles have a uniform particle size (single particle size), and the particle size is in the sieving particle size range but constant. Often have a particle size distribution of When the catalyst is a catalyst for a gas phase polymerization reaction of an olefin, any catalyst used in olefin polymerization can be used as long as it is a powdery catalyst. Generally, the solid catalyst is a catalyst containing at least one metal selected from transition metals such as titanium, vanadium, chromium, cobalt, nickel, zirconium and hafnium. Co-catalysts typically used in olefin polymerization, such as alkylaluminums, aluminoxanes, boron compounds, etc., can also be used in the reaction with or separately from the above catalysts. A catalyst preliminarily polymerized with an olefin can also be used. More specifically, so-called Ziegler-Na containing transition metals such as titanium and vanadium.
A tta catalyst; a chromium-based catalyst containing chromium oxide, a chromium complex or the like; a metallocene catalyst composed of a metallocene such as zirconocene; a so-called Brookhardt catalyst; a solid and powdery catalyst such as a cationic metal halide may be used. A solid powder catalyst, which is obtained by physically or chemically supporting the above transition metal catalyst alone or a mixture thereof with a cocatalyst on a fine particle carrier typically used in olefin polymerization, such as silica or alumina, is also used. can do. According to the method of the present invention, a uniformly dispersed and continuous powdery catalyst flow can be obtained, so that the dispersion of the catalyst immediately after the catalyst is injected into the reactor is good, which is suitable for the supply of a highly active catalyst. Can be applied. Therefore, for example, it can be suitably applied to catalyst supply for gas phase polymerization of an olefin using a solid metallocene catalyst in which a cocatalyst is also supported. The metallocene catalyst supporting not only the catalyst but also the co-catalyst expresses a high activity immediately in the charged reactor, but when it is supplied by the method of the present invention, the dispersed state of the catalyst becomes good, so that the bulk polymer It is particularly preferable because it can prevent the formation of

(Entrained Fluid) The powdery catalyst flows through a catalyst distribution system such as a catalyst supply pipe together with an entrained fluid which is a transport fluid, and finally supplied to the reactor. The fluid accompanying the catalyst may be a gaseous substance or a liquid substance which is inert to the reaction. It may also be a gaseous or liquid substance active for the reaction, for example, the reaction substrate itself such as ethylene or propylene. That is, even the reaction substrate itself can be used without any particular problem as long as it can be made inactive at least in the catalyst flow system by an operation such as cooling. Of course, in this case, it is desirable that the cooling be such that the supply of the catalyst and the reaction itself are not adversely affected. Preferred fluids are inert gases such as nitrogen, helium, argon and the like.

(Catalyst Meter) A catalyst meter is a device for measuring a certain amount of powdery catalyst, discharging it intermittently or intermittently, and discharging it to the catalyst flow system. Any structure of the weighing machine itself can be used as long as it has such a function. The metered amount of catalyst is substantially intermittently or intermittently discharged from the meter and then entrained in the fluid by suitable means. Further, the measurement of the catalyst in the catalyst measuring device can be performed according to the volume and / or the mass of the catalyst. The supply of the catalyst to the entrained fluid may be completely stopped once, or the amount of the catalyst entrained in the fluid may be pulsated with time without being completely stopped. That is, when a powdery catalyst is introduced into a flowing fluid and is entrained in the fluid, the flow of the fluid can be made to flow in synchronization with the flow of the catalyst introduced intermittently, or independently of this ( Fluids can also be flowed (without synchronization). In any case, it is included in the intermittent or intermittent supply of the powdery catalyst in the present invention, and the method of the present invention can be preferably applied. The amount measured by one measurement greatly varies depending on the catalyst activity, the type of reaction, the scale of reaction, and the like. In the case of an olefin gas phase polymerization catalyst, for example, it is about 0.1 to 100 at one time.
g, preferably about 1-10 g of catalyst is metered.
The number of times of measurement is not particularly limited, but it is usually 0.1 to 60 times per minute.

As a method for discharging the metered catalyst from the catalyst meter and entraining it in the fluid flow, there are methods as shown in FIGS. 1, 2 and 3. Here, in any of FIG. 1, FIG. 2 and FIG. 3, the powdery catalyst stored in the catalyst storage tank 1 naturally or forcibly falls into the catalyst measuring device 2 installed immediately below the storage tank 1, and the measuring device 2 In (1), a predetermined amount is measured, and the measured constant amount of powdery catalyst is then introduced into the fluid and entrained. In FIG. 1, the catalyst weighed by the catalyst weighing device 2 is supplied and entrained in the flow path of the entrained fluid due to gravity or a pressure difference. In FIG. 2, a method is adopted in which the metering portion of the catalyst metering device 2 is rinsed with the entrained fluid so that the catalyst stored in the metering portion is rinsed and entrained in the entrained fluid. In FIG. 3, the catalyst weighed by the catalyst meter 2 is once entrained in the flow path of the auxiliary fluid that is the same as or different from the entrained fluid due to gravity or pressure difference, and then the entrained catalyst together with the auxiliary fluid flows the original entrained fluid. An example of a method of incorporating and accommodating in. Either method can be adopted. In addition, although not shown, it is also possible to employ a structure in which the catalyst meter is temporarily disconnected from the flow of the entrained fluid when the catalyst is metered. In such a structure, the flow path of the entrained fluid may be temporarily changed, and at this time, the flow of the entrained fluid in the catalyst supply pipe may be changed due to the operation of the flow path valve such as the rotary valve for switching the flow path. It may stop substantially temporarily. When the flow of the fluid is temporarily stopped in this manner, a backflow of the reaction gas from the reactor is likely to occur, which may lead to blockage of the catalyst supply pipe. for that reason,
It is preferable that an inert fluid that is the same as or different from the entrained fluid is always flowed through the catalyst supply pipe so that the fluid flow in the catalyst flow system is not substantially stopped.
In any case, the powdered catalyst is intermittently or intermittently entrained in the fluid flow, but the fluid entrained with the powdered catalyst is preferably continuous. The above description of the catalyst meter is an example, and the catalyst is substantially intermittently supplied to the entrained fluid, so that the powdered catalyst entrained in the fluid may flow intermittently, intermittently or discontinuously. Any catalyst measuring instrument can be used and is not limited to the above description.

The powdery catalyst discharged intermittently or intermittently from the catalyst meter is entrained in a fluid, flows as a transport fluid in the catalyst supply pipe, and finally reaches the reactor.
The flow direction in the vicinity of the meter portion is not particularly limited, but is usually a horizontal flow. In particular, the measured powdery catalyst in the vicinity of the measuring device may be in the form of a nodule, and a flow in a substantially horizontal direction is preferable to a flow in a vertical direction because it is less likely to cause pipe clogging and the like. The flow velocity of the accompanying fluid flowing through the catalyst supply pipe is generally 0.1 to 60.
It is selected from the range of m / sec.

(Reactor) The reactor to which the powdery catalyst is supplied is either a liquid phase reactor or a gas phase reactor, preferably a gas phase polymerization reactor. More specifically, a polymerization reactor such as a gas phase fluidized bed, a gas phase stirred bed or a gas phase fluidized stirred bed reactor is exemplified. A catalyst supply pipe is connected to the reactor, and the powdery catalyst is supplied through the pipe. In the present invention, in the middle of the catalyst supply pipe from the catalyst metering device to the reactor, means for temporarily accumulating the flow of the powdery catalyst accompanying the fluid and flowing intermittently or discontinuously in the flow path is provided. Means for providing the concentration of the powdery catalyst in the flow direction is provided in the middle of the flow path. In addition,
A plurality of catalyst supply pipes may be connected to the reactor.

(Reaction) Any type of reaction may be used as long as it is a reaction using a powdery catalyst. The method of the present invention can be preferably applied to a reaction in which the degree of dispersion of the solid powder catalyst in the reactor is important. A reaction using a reactor having a gas phase fluidized bed, a gas phase stirred bed, or the like is preferable.

(Polymerization reaction) The reaction in which the powdery catalyst is used is preferably a polymerization reaction. The polymerization reaction is generally an exothermic reaction, and the polymer produced by the polymerization is generally a liquid or solid substance. In a gas phase polymerization reaction using a gas phase fluidized bed or a gas phase stirred bed reactor which is a preferable reactor, a polymer produced by the polymerization reaction is generally obtained as a solid powder. Here, if a region having a high catalyst concentration exists in the reactor due to poor dispersion of the catalyst, the temperature locally rises, which may cause an abnormal reaction. Further, even if an abnormal reaction of the entire polymerization reactor is not reached, a local temperature rise may lead to the formation of a lump polymer. In a gas-phase fluidized bed or a gas-phase agitated bed reactor, the polymer is discharged from the reactor as a solid powder, so the formation of a lump polymer leads to blockage of the polymer discharge pipe, and the operation of the polymerization reactor must be stopped. You may even lose your money. In addition, when agglomerates are formed, the reaction actually stops due to factors such as a decrease in the diffusion rate of the reactants in the agglomerates, and catalyst residues remain in a high concentration, and this residual catalyst residue affects the product. There is also. The method of the present invention can be suitably adopted even in the case of such a reaction.

Specific raw materials for the polymerization reaction include, for example, 2 to 4 carbon atoms as a monomer used in gas phase polymerization.
It is possible to select one kind or two or more kinds of 0 olefin or other monomer such as ethylene, propylene, isobutylene, styrene, butadiene, acrylonitrile, chloroprene, maleic acid or its derivative, acrylic acid or its derivative and the like. Examples of polymers obtained from such monomers include polyethylene, polypropylene, polyisoprene, polystyrene,
Polybutadiene, SBR, nitrile rubber, EPR, EPDM, neoprene, silicone rubber, copolymer of ethylene and vinyltrimethoxysilane, or copolymer of ethylene and acrylonitrile, maleic acid ester, vinyl acetate, acrylic acid ester, etc. Is mentioned. In the case of gas phase polymerization, a reaction mode such as so-called condensation mode polymerization in which a liquid component is present in the reactor for cooling by utilizing latent heat of vaporization or dry mode polymerization in which substantially no liquid component is present. However, any method can be adopted in the method of the present invention.

(Staying means) In order to disperse the powdery catalyst which is intermittently or intermittently supplied by reducing the temporal fluctuation of the concentration, a midway of the flow path of the powdery catalyst supply pipe is set as a staying region. Further, there is provided a retention means that has a function of retaining the powdery catalyst substantially temporarily. The powdered catalyst weighed by the weighing device may be in the form of a nodule in some cases,
Although a constant speed is required as a transport fluid for transporting this, it is difficult to make the concentration in the flow direction uniform because the transport fluid may move in an agglomerated (plug-like) form if simply transported. Therefore, in the present invention, the flow of the powdery catalyst is substantially temporarily decelerated inside the supply pipe so as to stay therein, and any form is possible as long as it is possible. Specifically, a method of increasing the inner diameter of the supply pipe to decelerate and stagnant the flow can be adopted. Since the powdery catalyst flows in the pipe intermittently, intermittently or discontinuously, it is usually not preferable that the catalyst flow is blocked even if the catalyst flow is retained even temporarily. It is generally considered that, in the present invention, the powdery catalyst in an intermittent or intermittent flow is dispersed by adopting a structure in which a temporary residence of the catalyst occurs, and the powdery catalyst concentration Continuous in the flow direction,
It can be made uniform.

The accumulating means has a part of the catalyst flow system between the catalyst metering device and the reactor as a region having a function capable of temporarily accumulating the catalyst, and a preferable mode of increasing the cross-sectional area of the flow path. It can be an area to be made. It is possible to connect the flow path with an increased cross-sectional area to the reactor with the same cross-sectional area, but once the powdered catalyst is evenly dispersed, it is unlikely to be discontinuous after that, so it is convenient for equipment and piping. It is preferable to reduce the cross-sectional area of the flow path which has been increased from the top again. If it is decreased, it may be the same as the original cross-sectional area, or it may be an increased or decreased cross-sectional area. When the retention area is formed by increasing the cross-sectional area of the flow path of the catalyst flow system and then decreasing it, the area exhibits a container-like or room-like area.
Therefore, for example, a cylinder having a diameter larger than the pipe diameter of the flow passage can be provided in the middle of the flow passage of the catalyst supply pipe. The shape may be prismatic, but is preferably cylindrical.

At least one retention area as the retention means of the present invention is installed between the catalyst meter and the reactor, and a plurality of retention areas can be installed according to the purpose. These should be installed in series or in parallel. You can also Even if the improvement in the temporal uniformity of the catalyst supply amount is insufficient in one retention region,
By providing a plurality of retention areas, it may be possible to make it more uniform. Generally, by providing a plurality of retention regions, it is easy to maintain the temporal uniformity of the catalyst supply amount even when the flow rate of the accompanying fluid changes. Further, even when the amount of catalyst that can be supplied varies depending on the reaction or the state of the catalyst, it is possible to relatively easily approach the optimum supply state by changing the number of retention regions.

Specific dimensions and the like of the container or room-like shape forming the retention area are the inner diameter thereof, the positions of the inlets and outlets of the entrained fluid and their relations, and the installation method thereof, specifically, for example, the catalyst meter. Vertically launching a pipe downstream of the and installing a retention area in front of it, such as type of entrained fluid, flow rate, amount of measured catalyst, supply time interval of measured catalyst, entrainment method of catalyst and entrained fluid, etc. It depends on the condition. In addition, it is possible to determine the appropriate shape and installation method of the required retention region by experimentally obtaining the allowable range of the fluctuation of the catalyst concentration over time in the catalyst supply according to the specific equipment and operating conditions. it can. In these retention areas, it is preferable to have a shape that does not cause a dead space inside. Specifically, it is preferable to avoid a sudden change in the flow passage cross-sectional area at the inlet or the outlet of the powdery catalyst flow in the retention region, and thus a shape that does not increase or decrease the cross-sectional area discontinuously, For example, a conical shape is preferable. Further, in the case where the powdery catalyst flow which is a preferred embodiment is installed in the vertical direction as described below, when the angle formed by the conical surface of the inflow part with the horizontal plane is larger than the repose angle of the powdery catalyst, the conical shape It is preferable that the catalyst particles are less likely to be deposited in the inflow portion of. In the retention area of the present invention, since the purpose is to reduce the concentration change over time of the powdered catalyst that is intermittently supplied and to supply it to the reactor, it is possible to continuously flow a fluid for entrainment. preferable. Normally,
Since the entrained fluid is continuously flowed, the entrained fluid entrained with the powdery catalyst discharged from the catalyst meter is introduced into the retention region as it is. In the case where the entrained fluid is caused to flow intermittently, it is preferable to devise so as to further promote homogenization by providing two or more retention regions.

(Installation direction of retention area) If the flow direction of the entrained fluid in the retention area is a substantially upward upward flow (flow in the direction opposite to the direction of gravity), the powder whose concentration does not fluctuate over time is small. It is preferable because the flow rate of the entrained fluid required to develop the fluidized state of the catalyst is minimized. When there are restrictions on the choice of the type of entrained fluid, the flow rate, the shape of the retention region, etc., the direction of the entrained fluid flow should be at a constant angle with respect to the vertical upward direction rather than being exactly upward. In some cases, it may be possible to achieve a supply state of the powdery catalyst with less time-dependent concentration fluctuation in the direction, that is, diagonally above. The flow direction here means the overall flow direction of the entrained fluid. If the flow is limited to a very small area, the flow may have complicated movements. Especially, the flow is complicated in a portion where the cross-sectional area of the flow path changes, for example, in the retention area. However, here we mean the overall flow direction of the entrained fluid entrained with the powdered catalyst. By making the direction of the flow of the entrained fluid substantially vertical as described above, it becomes easy to temporarily retain the catalyst due to the balance between the acting force of the flow of the entrained fluid and the gravity of the catalyst particles. . Therefore, it is preferable that the entrained fluid flows upward. When a container or a room-like retention area is installed as the retention means, it is preferable to have a structure in which the fluid enters from the lower part of the area and escapes from the upper part. When the flow of the entrained fluid is directed vertically upward in this way, the powdery catalyst particles in the retention vessel are subjected to the acting force of the fluid in the upward flow direction and the downward gravity, and thus the large number of particles having a particle size distribution. The group is up and down,
That is, the powdery catalyst flows and disperses in the flow direction. Then, by flowing and dispersing, the concentration of the powdery catalyst can be made uniform in the flow direction, and as a result, the powdery catalyst can be continuously supplied to the reactor.

In the retention area, the linear velocity of the entrained powdery particles is substantially reduced as compared with that before the inflow, thereby causing a temporary retention state. If the containers or room-like regions are provided as a preferred embodiment for this, they increase the cross-sectional area of the fluid flow path. In the present invention, the increase ratio of the cross-sectional area of the flow path in the retention area is preferably 100% or more, more preferably 200% or more, and further preferably 500% or more with respect to the cross-sectional area before the inflow of the maximum cross-sectional area portion. is there. Normally, the catalyst supply pipe before inflow is pipe-shaped and has an inner diameter of 1 to 50.
Since the diameter is mm, a cylindrical or room-like region having an inner diameter larger than that of the region before inflow by about 40% or more can be used as the retention means. If the cross-sectional area is increased in this way, the degree of freedom of diffusion of the powdery catalyst in the direction perpendicular to the flow direction increases and the dispersion becomes easier. However, if the cross-sectional area of the flow path in the retention region is made too large, the linear velocity of the entrained fluid becomes too small, and as a result, in the extreme, when the entrained fluid flow direction is the upward direction, the entrained fluid is more likely to rise The sedimentation of the catalyst particles due to gravity is predominant, and it becomes difficult for the catalyst particles to rise in the retention area, and it becomes difficult to transport the powdery catalyst by the entrained fluid. Therefore, when the flow direction in the retention area is set to the vertically upward direction, which is the preferred embodiment described above,
The cross-sectional area of the flow passage is equal to or less than the cross-sectional area at which the entrained fluid gives a fluidization start speed to the powdery catalyst, that is, the superficial velocity in the retention region is equal to or higher than the fluidization start speed of the powdery catalyst due to the entrained fluid. Is preferred. Specifically, the superficial velocity of the fluid in the retention region is preferably 0.3 to 3 times, more preferably 0.5 to 3 times the terminal velocity of falling in the fluid accompanied by the powdery catalyst. It is desirable that the range is double. The fluidization start velocity, superficial velocity, and terminal velocity can be separately calculated according to the theory of the fluidized bed.

Furthermore, as described above, the powdery catalyst is usually classified, but usually has a uniform particle size distribution. When the entrained fluid has a structure that rises in the retention region, the powdery catalyst has different settling force due to gravity depending on the particle size. As a result, classification of the powdery catalyst having a particle size distribution may occur in the retention area. That is, catalyst particles with a large particle size rise slowly in the retention area, and do not even rise in an extreme case, while powdery catalysts with a small particle size rise quickly, and in the extreme case, only particles with a small particle size. Will escape from the retention area. Such a situation is of course not preferable, and as one method for avoiding this, it is possible to adopt a method in which the height of the retention region in the flow direction, that is, the flow path length in the retention region is not excessively long. it can. Of course, if the flow path length is too short, the catalyst is not temporarily retained substantially, which is not preferable. Generally, the flow path length of the powdery catalyst in the retention region is 1 cm to 5
m, preferably 2 cm to 3 m. In other words, it is preferable that the flow path length of the portion where the cross-sectional area of each retention region is increased is set within the above range. The powdery catalyst that has left the retention area is entrained in the fluid and supplied into the reactor through the catalyst supply pipe. Once dispersed and homogenized, the powdered catalyst rarely agglomerates again in the fluid, so even if it is a vertically upward flow in the retention area, it is directly connected to the subsequent site, for example, the reactor. It is also possible to install the catalyst supply pipe part of the portion to be installed horizontally so that the catalyst entrained flow is supplied to the reactor in a horizontal flow.

[0025]

EXAMPLES The present invention will be described in detail below with reference to examples. The polymerization reaction device shown in FIG. 4 was used. That is, the powdery catalyst in the catalyst storage tank 1 is weighed by the catalyst weighing device 2 by a predetermined amount and then dropped and discharged by gravity. This catalyst is transferred by an auxiliary fluid, and is further transported by a vertically upward flow of an entrained fluid to a container-shaped retention region (retention container) 3 to make the catalyst concentration uniform, and then converted to a horizontal flow to form a polymerization tank. 4 is supplied. With respect to the supply line to the polymerization tank 4, ethylene and hexene-1 reaction raw materials are put into the polymerization tank 4 from below, ethylene and the like are polymerized by the introduced powdery catalyst, and the polymer is an upper portion of the polymerization tank 4. Emitted from. The unreacted monomer in the polymerization tank 4 is circulated from the upper portion by a circulation line, recovered by the circulation gas compressor 6 and the circulation gas cooler 5, and again used for the polymerization reaction. Although not shown, the polymer is extracted from the circulation line. (Catalyst) A silica-supported zirconocene-based metallocene-type olefin polymerization catalyst was used. The average particle size of the catalyst is 5
It is 0 μm, and carries a co-catalyst, methylaluminoxane. Therefore, it is highly active and has no induction period, etc., and it polymerizes immediately when it comes into contact with the reaction raw material under the polymerization conditions. (Reaction) These monomers were copolymerized by introducing ethylene and hexene-1 into a gas-phase fluidized bed reactor.
The polymerization conditions for the gas phase fluidized bed are as follows. -Polymerization pressure: 2 MPa-G-Polymerization temperature: 65 ° C to 75 ° C (reactor) Gas-phase fluidized bed reactor. (Catalyst meter) The catalyst meter measures a certain amount of powdery solid catalyst by volume, and each time the measured powdery catalyst is dropped and discharged by the gravity to the outside of the metering system, and the dropped and discharged catalyst is The structure is such that it is entrained in the auxiliary fluid and is further transported in the catalyst supply pipe by the entrained fluid (see FIGS. 3 and 4). The amount of catalyst weighed in at one time is about 2.5 g, and about 0.1 g per minute.
It was weighed 5 times and supplied intermittently. Nitrogen was used for both the auxiliary and accompanying fluids. The flow velocity of the entrained fluid is 5 m / sec. (Staying means) As shown in FIG. 4, in the middle of the catalyst supply pipe,
A container-shaped retention region (retention container 3) was provided. The retention container 3 used is shown in a vertical sectional view in FIG. As shown in the vertical sectional view of FIG. 5, it has a structure in which four containers are connected in series. Each of the two retention vessels was of an integral type, and the integral vessels were connected by a catalyst supply pipe. The retention container 3 was installed vertically, and the flow direction of the entrained fluid flowing therein was vertically upward. Nitrogen, which is an inert fluid, was used as the entrained fluid, and the powdery catalyst was dropped or discharged intermittently or intermittently from the catalyst meter 1, but the entrained fluid continuously flowed. The shape of the retention container 3 is a cylindrical shape as shown in FIG. Has a structure. The angle formed by the conical surface of the inflow portion and the horizontal surface was set to be larger than the repose angle of the powdery catalyst. The inner diameter was 22 mm in all except the entrance / exit portion. The length of the cylindrical portion of one container is 146 mm (the height of the portion corresponding to the inner diameter of 22 mm). All catalyst supply pipes had an inner diameter of 4 mm. The increase in cross-sectional area in the retention container is 2925%.

<Example 1> The powdery catalyst that had risen and passed through the retention vessel 3 was introduced into the polymerized layer 4 through a catalyst supply pipe that was horizontally provided along with nitrogen as a transport gas.
Ethylene and hexene-1 were introduced from the lower part of the polymerized layer 4 in FIG. The gas-phase fluidized bed reactor was operated by a conventional method as described above, but even after 100 hours, no sheeting was generated on the reactor wall surface, and as a result, white free-flowing particles having a density of 0.905 g / cm 3 were obtained. An ethylene / hexene-1 copolymer with ³ and MFR of 3.5 g / 10 min was obtained. In the obtained polymer, brown blobs exhibiting a catalyst color were not particularly observed, and the obtained polymer powder was molded into a film by a conventional method, and the gel contained in the film was analyzed to detect the small gel. Was as small as 15 pieces / 100 cm ² .

<Comparative Example 1> For comparison, a catalyst supply pipe having the same flow path length as that of the retaining vessel of Example 1 without using any of the above four retaining vessels (without providing a retaining region). Copolymerization was performed in the same manner as in Example 1 except that the connection was made (inner diameter 4 mm). As a result, in the obtained polymer powder, formation of brown small particles showing a catalyst color was observed, which was due to poor dispersion of the catalyst. The product obtained by removing the small lumps was formed into a film by an ordinary method, and gel analysis was performed on the obtained film.
A large number of pieces / 100 cm ² were detected.

[0028]

EFFECTS OF THE INVENTION According to the present invention, even in the case of using a catalyst supply device for measuring a powdery catalyst in a catalyst metering device and intermittently transporting it to a fluid, there is little fluctuation in catalyst concentration over time. The catalyst can be fed to the reactor at.
As a result, it is possible to prevent abnormal reaction due to insufficient dispersion of the catalyst, generation of bulk polymer in the polymerization reaction, and occurrence of sheeting, and it is possible to perform operation with excellent quality and stability.

[Brief description of drawings]

FIG. 1 is a diagram showing an example in which a catalyst in a catalyst meter is dropped from a meter and is entrained in a fluid flow.

FIG. 2 is a diagram showing another example in which the catalyst in the catalyst meter is entrained in the flow of the fluid by a method of flushing with the fluid.

FIG. 3 is a view showing still another example in which the catalyst in the catalyst meter is entrained in the fluid flow by the auxiliary fluid.

FIG. 4 is a schematic system diagram showing a specific example of a method for supplying the powdery catalyst of the present invention to a reactor.

FIG. 5 is a partial vertical cross-sectional view showing a specific example of a retention container used in the present invention.

[Explanation of symbols]

1 catalyst storage layer 2 catalyst meter 3 Retention container 4 polymerization tank 5 Circulating gas cooler 6 Circulating gas compressor

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Masahiro Niwa             10-1 Chidori-cho, Kawasaki-ku, Kawasaki-shi, Kanagawa             This polyolefin Co., Ltd. Kawasaki factory F-term (reference) 4J011 BA01 BB02 BB03 BB04 BB05                       BB17 BB18

Claims (10)

[Claims] 1. A means for temporarily accommodating a flow of a powdery catalyst flowing in a flow path in an intermittent or discontinuous manner in association with a fluid, is provided in the flow path, whereby the powdery catalyst A method for supplying a powdery catalyst, characterized in that the concentration is made uniform with respect to the flow direction and is supplied to the reactor. 2. The method for supplying a powdery catalyst according to claim 1, wherein the flow direction of the powdery catalyst in the retaining means is substantially vertically upward. 3. The method for supplying a powdery catalyst according to claim 1, wherein the retention means comprises increasing the cross-sectional area of the flow path. 4. The method for supplying a powdery catalyst according to claim 3, wherein the increase in the cross-sectional area of the flow channel is 100% or more. 5. The method for supplying a powdery catalyst according to claim 1, wherein the powdery catalyst is substantially fluidized by an entrained fluid in the retaining means. 6. The method for supplying a powdery catalyst according to claim 1, wherein a plurality of the retention means are provided in the middle of the flow path. 7. The structure according to claim 3, wherein the cross-sectional area of the retaining means increases once and then decreases again.
Alternatively, the method for supplying the powdery catalyst according to item 4. 8. The method for supplying a powdery catalyst according to claim 1, wherein the powdery catalyst is a gas phase polymerization catalyst. 9. The method for supplying a powdery catalyst according to claim 8, wherein the gas phase polymerization is olefin polymerization. 10. The method for supplying a powdery catalyst according to claim 8, wherein the gas phase polymerization uses a fluidized bed and / or a stirred bed reactor.