JP4627112B2 - Agglomerated substance detection method, agglomerated substance detection apparatus, fluidized bed olefin polymerization reaction apparatus equipped with the apparatus, and olefin polymerization method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for detecting an agglomerate produced in a mixed phase vessel such as a fluidized bed olefin polymerization reaction vessel, an apparatus for detecting the agglomerate, a fluidized bed olefin polymerization reaction device equipped with the device, and an olefin polymerization method. It is about.
[0002]
[Prior art]
As a method for detecting an agglomerate produced in a mixed phase vessel such as a fluidized bed olefin polymerization reaction vessel, a method utilizing radiation is known (for example, see Japanese Examined Patent Publication No. 62-28961). This is because the radiation source is arranged at the center of the container, and a plurality of radiation detectors are arranged on the outer periphery of the container to detect the density change of the mixed phase existing between the radioactive source and the detector, and to agglomerate It is to know the existence and the size of.
[0003]
As another method, there is a method in which capacitance detection means is arranged on the inner wall of the mixed phase container (Japanese Patent Laid-Open No. 4-361150). This is because the density of the agglomerate is larger than the density of the mixed phase, and when the gel-like agglomerate is generated and adhered to the inner wall surface in the mixed phase container, the capacitance of the inner wall surface changes. It is intended to detect the production state of the agglomerate by measuring.
[0004]
As another method, there is a method in which a detection rod provided with strain detection means is arranged in a mixed phase container (Japanese Patent Laid-Open No. 10-36447). In this case, the presence and the size of the agglomerate are known from the amount of distortion generated when the produced agglomerate collides with the detection rod. That is, by arranging a detection rod inside the mixed phase container and providing a strain gauge on the detection rod, the strain of the detection rod due to the collision of the agglomerates is measured, and the presence and size of the agglomerates are known. It is a thing.
[0005]
[Problems to be solved by the invention]
However, in the above-described method for detecting agglomerates using radiation, for example, in a fluidized bed olefin polymerization reaction vessel, the vessel generally has a huge substantially cylindrical shape with a diameter of several meters and a height of several tens of meters. When a blockage occurs in the interior or when a periodic inspection is performed, it is necessary for an operator to enter the container and remove the blockage or perform an inspection operation. Therefore, when a radiation source is arranged in the container, it is necessary to give sufficient consideration to ensuring the safety of the work in the container.
[0006]
Further, in the detection method using the capacitance detection means, there is no problem regarding ensuring the safety, and the agglomerated material moving in the container is suitable for detection of the agglomerated material adhering to the inner peripheral wall of the mixed phase container. It is not enough for detection. Furthermore, when the generated agglomerated material is still small, the density difference between the normal olefin polymer and the agglomerated material is small, and detection of the agglomerated material adhering to the inner wall surface of the container is not sufficient.
[0007]
On the other hand, the detection method using the strain detection means does not have these problems, but the agglomerate must collide with the detection rod effectively. Since the generated agglomerated material moves along the flow of gas or particles inside the mixed phase, if the flow of the gas or particles inside the mixed phase is not known in advance, it is effective for the detection rod due to the agglomeration collision. There is a case where the detection sensitivity is remarkably lowered without being given an impact.
[0008]
In addition, since a strain gauge is used, the measured value is a proportional value of the strain amount of the detection rod. Therefore, when the agglomerated material that collides is small, the measured value does not change slightly and it is difficult to detect this. That is, the detection sensitivity of the agglomerates is not sufficient, and it is generally difficult to detect agglomerates of 500 g or less.
Furthermore, when the agglomerate is large, the agglomerate may stay in the detection rod part. However, when the strain gauge is used, if the agglomerate stays in the detection bar part, the distorted state continues and the detection rod The signal continues to be output from and the generation of new agglomerates and changes in the mixed phase cannot be detected.
[0009]
The present invention has been made in view of the problems of the prior art as described above, and is an agglomerated substance detection method and an agglomerated substance that are highly safe, capable of detecting even small agglomerated substances, and capable of performing highly sensitive and highly accurate detection. It is an object of the present invention to provide a compound detection apparatus, a fluidized bed olefin polymerization reaction apparatus equipped with the apparatus, and an olefin polymerization method.
[0010]
[Means for Solving the Problems]
In order to solve such a problem in the prior art, the present invention according to claim 1 is configured to detect an agglomerate in a mixed phase container in which a mixed phase is formed by gas and powder and fluidized. In the detection method, a protective tube with one end fixed to the mixed phase vessel and the other end free is disposed inside the mixed phase vessel, and a detection rod is inserted into the free end of the protective tube. The magnet is attached to the other end of the detection rod, the magnet is placed in a uniform magnetic flux, and the magnet is moved using one point of the detection rod as a fulcrum to move the magnet. The change of the magnetic flux accompanying it is measured, and presence of a lump-like agglomerate is detected. Thereby, the production | generation state of an agglomerate is detectable on the basis of the proportional value of the moving speed of the permanent magnet accompanying the collision of an agglomerate.
[0011]
In another embodiment of the present invention, a detection rod having a part fixed to the mixed phase vessel and free at one end is disposed inside the mixed phase vessel, and a magnet is attached to the other end of the detection rod to be uniform. And the magnet is moved with one point of the detection rod as a fulcrum, and the change of the magnetic flux accompanying the movement of the magnet is measured to detect the presence of a lump-like agglomerate. To do.
[0012]
Furthermore, a particle swirl type dispersion plate is arranged below the inside of the mixed phase container, the circulating gas is blown out horizontally, and the detection rod is installed at a predetermined height above the particle swirl type dispersion plate. It is also a feature. Thereby, the flow of gas or particles inside the mixed phase container can be controlled, and the agglomerate can be effectively collided with the detection rod.
[0013]
An agglomerated substance detection apparatus according to the present invention is an agglomerated substance detection device for detecting agglomerated agglomerated substance in a mixed phase container in which a mixed phase is formed and fluidized with gas and powder, and the mixed phase container A protective tube with one end fixed to the mixed-phase container and the other end free is disposed inside, and a detection rod is inserted into the free end of the protective tube, a part of which is fixed, and the detection A magnet that moves in a uniform magnetic flux with one point of the detection rod as a fulcrum is attached to the other end of the rod, and magnetic flux detection means for detecting a change in the magnetic flux accompanying the movement of the magnet is provided. Is. Thereby, the production | generation state of an agglomerate is detectable on the basis of the proportional value of the moving speed of the permanent magnet accompanying the collision of an agglomerate.
[0014]
In addition, a particle swirl type dispersion plate that blows circulating gas horizontally and circumferentially is disposed at the bottom of the mixed phase container, and the detection rod is installed at a predetermined height above the particle swirl type dispersion plate. It is also a feature. Thereby, the flow of gas or particles inside the mixed phase container can be controlled, and the agglomerate can be effectively collided with the detection rod.
[0015]
The fluidized bed olefin polymerization reaction apparatus according to the present invention is characterized by including the agglomerate detection apparatus described above.
[0016]
The olefin polymerization method according to the present invention is characterized in that the agglomerated material in the mixed phase vessel is detected by the agglomerated material detection method described above, and the agglomerated material is extracted and removed from the mixed phase vessel.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention applied to a fluidized bed olefin polymerization reaction vessel as a mixed phase vessel will be described with reference to the drawings.
[0018]
FIG. 1 is a diagram showing a fluidized bed olefin polymerization reaction vessel and its surrounding piping system. Inside the fluidized bed olefin polymerization reaction vessel 1 as a mixed phase vessel, a mixed phase of gas and powder is formed and fluidized, and the polymerization reaction proceeds in this state. The pressure in the fluidized bed olefin polymerization reaction vessel 1 is about 1 to 3 MPa, and the temperature is about 70 to 100 ° C.
[0019]
In the fluidized bed olefin polymerization reaction vessel 1, a catalyst and an olefin gas such as ethylene gas are supplied from an inlet 4, and a circulating gas blower 5 constantly circulates a circulating gas via a gas line 7. The heat exchanger 6 in the circulation gas path is for adjusting the temperature of the circulation gas.
[0020]
A product such as powdered polyethylene or polypropylene produced by the polymerization reaction in the fluidized bed olefin polymerization reaction vessel 1 is sent to the primary silo 10 through the discharge valve 8 and the discharge line 9 and temporarily stored. The product is further cut out to the air feed line 13 by the rotary valve 11 and sent to a desired place by the wind force of the air blower 12.
[0021]
FIG. 2 is an enlarged view of the bottom portion of the fluidized bed olefin polymerization reaction vessel 1, with a part thereof cut away so that the internal structure can be seen. The circulating gas fed from the lower part of the fluidized bed olefin polymerization reaction vessel 1 is blown upward from the respective opening holes 21 provided in a large number in the dispersion plate 2. And a mixed phase of powder is formed. And polymerization reaction advances in it.
[0022]
In the process, a lump-like agglomerated material 20 is generated due to a change in state of the mixed phase. This generation process is not yet fully understood.
While the generated agglomerated material is small, the agglomerated material circulates inside the mixed phase in a floating state with the flow of particles inside the mixed phase. As the agglomerates grow and grow, the agglomerates are no longer fluidized with the particles and settle in the mixed phase. Such agglomerates generally stay in the vicinity of the dispersion plate or move irregularly due to the circulating gas from the openings of the dispersion plate.
[0023]
Here, in order to move such a large agglomerate on the dispersion plate 2, the applicant assigns directivity to the circulating gas from the opening holes 21 of the dispersion plate 2, for example, in the same circumferential direction. A particle swirl type dispersion plate that generates a flow of gas and particles in the circumferential direction on the dispersion plate by directing the opening hole 21 was developed and a patent application was filed (see JP-A-6-136003). In the present embodiment, this particle swirl type dispersion plate is used as the dispersion plate 2.
[0024]
As shown in FIG. 3, the particle swirl type dispersion plate 2 has an opening hole 21 for blowing out gas arranged on a circumference concentric with the container cross section, and a streamlined cap 22 on the opening hole 21. Is provided. Thereby, the gas is blown out in the horizontal direction along the opening hole 21 of the particle swirl type dispersion plate 2. In FIG. 3, a counterclockwise gas flow occurs.
Therefore, even a large agglomerate as described above can be swung on the particle swirl type dispersion plate 2 in a certain direction (counterclockwise in FIG. 3) on the gas flow. The behavior of the agglomerate inside the mixed phase depends not only on the size but also on the operating conditions such as the gas flow rate, but even a large agglomerate can be moved at a high gas flow rate.
[0025]
By the way, in the fluidized bed olefin polymerization reaction vessel 1, as shown in FIG. 2, as shown in FIG. 60 and a protective tube 51 are provided. Hereinafter, details of the detection rod 60 and the protective tube 51 will be described.
[0026]
4 is a side sectional view showing the internal structure of the detection rod 60 and the protective tube 51, and FIG. 5 is an enlarged sectional view taken along line AA of FIG.
One end of the protective tube 51 is fixed to the peripheral wall of the fluidized bed olefin polymerization reaction vessel 1 and the other end is free, so that it protrudes into the fluidized bed olefin polymerization reaction vessel 1 in a so-called cantilevered support state. It is installed at a predetermined height from the particle swirl type dispersion plate 2. The detection rod 60 is basically housed in the stainless steel hollow cylindrical protective tube 51.
[0027]
The protective tube 51 includes a large-diameter fixed portion 52 (for example, an outer diameter of 48 mm and an inner diameter of 15 mm) and a small-diameter protruding portion 53 (an outer diameter of 22 mm and an inner diameter of 12 mm). The detection rod 60 is basically housed in the protective tube 51, and flows through the flange 54 in a state where the fixed portion 52 of the protective tube 51 penetrates the peripheral wall of the fluidized bed olefin polymerization reaction vessel 1. The bed olefin polymerization reaction vessel 1 is fixed.
A protruding portion 53 of the protective tube 51 protrudes in the fluidized bed olefin polymerization reaction vessel 1. As a result, the agglomerate 20 generated in the reaction vessel 1 rides on the swirling flow and moves inside the reaction vessel 1 and collides with the protective tube 51. Due to this collision, the protective tube 51 is bent in the collision direction.
[0028]
The detection rod 60 is inserted over almost the entire length of the protective tube 51, and a part of the detection rod 60 is fixed, and one end thereof (the end portion on the protruding portion 53 side of the protective tube 51) is F1, F2 in FIG. These are fixed to the protective tube 51 by screws to the protective tube 51 at two points. One end of the opposite side is free, and the detection rod 60 is inserted into the protective tube 51 and fixed in a so-called cantilevered state.
[0029]
Here, since the outer diameter (for example, 10 mm) of the detection rod 60 is formed smaller than the inner diameter of the fixing portion 52 of the protective tube 51 and the inner diameter of the protruding portion 53, it is between the detection rod 60 and the protective tube 51. There is a gap. Accordingly, the detection rod 60 moves in the gap with the screwing point F1 as a fulcrum according to the movement (deflection) of the protruding portion 53 of the protective tube 51.
[0030]
As shown in FIGS. 4 and 5, two cylindrical permanent magnets 61 are attached to one end of the detection rod 60 made free in the direction orthogonal to each other. It is stored inside a room 55 provided at the base of the protective tube 51.
[0031]
In addition, on the lower surface and the left side surface of the chamber 55 (pointing to the lower side and the left side in FIG. 5), coils 70 serving as magnetic flux detection means are installed corresponding to the permanent magnets 61 of the detection rod 60. That is, the coil 70 is installed so that the axis of the coil 70 and the axis of the cylindrical permanent magnet 61 substantially coincide. In the present embodiment, the permanent magnet 61 is disposed so that a part of the tip of the permanent magnet 61 is inserted into the coil 70 in a normal state.
[0032]
When the agglomerated material 20 collides with the protective tube 51 as described above, the protective tube 51 and the detection rod 60 fixed to the protective tube 51 are bent in the collision direction, and the detection rod 60 moves in the gap. The permanent magnet 61 attached to the detection rod 60 also moves with this.
The movement of the permanent magnet 61 changes the magnetic flux in the corresponding coil 70. By measuring the change of the magnetic flux with the coil 70 as the magnetic flux detecting means, it is possible to know the presence and size of the agglomerate 20 in the container.
[0033]
The output signal from each magnetic flux detection means (coil 70) is input from the cable 16 to the converter 17, where it is converted into a current signal of, for example, 4 to 20 mA, and then the recording alarm unit 19 via the cable 18. To be monitored.
As described above, the two permanent magnets 61 and the coil 70 are provided so as to be orthogonal to each other. Therefore, even if the agglomerate 20 collides with the protective tube 51 from any direction, The coil 70 can measure the change in magnetic flux.
[0034]
If it demonstrates in detail, if the magnetic flux in the coil 70 will change, the induced electromotive force e shown below will generate | occur | produce.
e = −N × dΦ / dt = NBlv
Here, N: number of turns of coil 70, dΦ / dt: change in magnetic flux per unit time, B: magnetic flux density of coil 70, l: length of element of coil 70, v: moving speed of permanent magnet The
[0035]
That is, when the protection tube 51 and the detection rod 60 fixed to the protection tube 51 are bent due to the collision of the agglomerated material 20, the permanent magnet 61 attached to the detection rod 60 moves, and the coil 70 moves the permanent magnet 61. An induced electromotive force proportional to the speed is generated. Therefore, by measuring the change in the voltage of the coil 70, the generation state of the agglomerated material 20 can be known.
[0036]
Thus, based on the change in the magnetic flux generated by the movement of the permanent magnet 61 attached to the detection rod 60, the production state of the agglomerate 20 in the fluidized bed olefin polymerization reaction vessel 1 can be detected, and the coil From the amount of voltage change of 70 and this period, the frequency and magnitude of collision of the agglomerated material 20 with the protective tube 51 can be specified.
[0037]
Here, this dielectric electromotive force is a proportional value of the moving speed of the permanent magnet 61. Therefore, even if the amount of movement of the permanent magnet 61 is small due to the collision of a relatively small agglomerate, the tip of the detection rod moves, and as a result, when the magnet moves, an induced electromotive force is generated, which can be measured. it can. That is, even a collision of a small agglomerated material 20 can be detected, and the detection sensitivity of the agglomerated material 20 in the fluidized bed olefin polymerization reaction vessel 1 can be increased. In the present embodiment, even an agglomerate 20 of 500 g or less can be detected.
[0038]
The detection rod 60 is attached to the side surface of the fluidized bed olefin polymerization reaction vessel 1, and the height h from the particle swirl type dispersion plate 2 (see FIG. 2), that is, the predetermined height is discharged. The height may be any height as long as it can detect the agglomerate 20 having such a size that the agglomerate 20 can be extracted from the valve 8, for example, 5 to 15 cm.
[0039]
FIG. 6 shows an experimental result when the detection rod 60 having the above-described configuration is actually arranged in the fluidized bed olefin polymerization reaction vessel 1 and the agglomerate 20 generated in the reaction vessel 1 is detected. . The horizontal axis indicates time, and the vertical axis indicates the amount of change in voltage, that is, the amount of change in magnetic flux. In a normal state, a certain load is applied to the protective tube 51 due to the swirl flow in the fluidized bed olefin polymerization reaction vessel 1, but the portion where the voltage change amount is stable in this figure is in this normal state. Show. On the other hand, the portion where the voltage change amount protrudes indicates that the agglomerate 20 has collided with the protective tube 51.
[0040]
Even when the particle swirl type dispersion plate described above is used, it is considered that particles or agglomerates move not only in the horizontal direction but also in the vertical direction. Due to the provision of means 60, such vertically moving particles or agglomerates can also be captured.
[0041]
In addition, since the agglomerated material that has moved along the flow of the gas or particles may be caught by the protective tube 51 and stay as it is, the insertion angle of the protective tube 51 from 20 degrees with respect to the flow of the gas and particles. If it arrange | positions inclining so that it may become 70 degree | times, it can reduce that the agglomerate produced | generated in the mixed phase container is caught in the protective tube 51. FIG. Thereby, detection with higher sensitivity and higher accuracy can be performed.
[0042]
Here, FIG. 7 shows a side sectional view of a detection rod 60 according to another embodiment of the present invention.
In this embodiment, the protective tube described above is not provided. A part 62 of the detection rod 60 is fixed to the mixed phase vessel on the peripheral wall of the fluidized bed olefin polymerization reaction vessel 1 and one end is free, and the detection rod 60 is exposed in the fluidized bed olefin polymerization reaction vessel 1. The coil 70 as the magnetic flux detection means is fixedly provided to the fluidized bed olefin polymerization reaction vessel 1.
As a result, the change in magnetic flux due to the movement of the permanent magnet 61 attached to one end of the detection rod 60 can be measured in the same manner as in the above embodiment. Therefore, the configuration of FIG. You can know the existence and size.
[0043]
【The invention's effect】
As described above, according to the present invention, the agglomerated material collides with the protective tube and the detection rod fixed to the protective tube, so that the magnet attached to the detection rod moves in a uniform magnetic flux. Since the agglomerate generation state is detected based on the change in the magnetic flux due to the movement, the agglomerate generation state is detected based on the proportional value of the moving speed of the permanent magnet accompanying the agglomerate collision. Even an agglomeration collision can be easily detected. Therefore, the detection sensitivity of the agglomerates in the mixed phase container can be increased.
[0044]
Further, the particle swirl type dispersion plate is disposed at the bottom of the mixed phase container, the circulating gas is blown out in the horizontal direction, and the detection rod is installed at a predetermined height above the particle swirl type dispersion plate. The flow of gas or particles inside can be controlled, and the agglomerate can be effectively collided with the detection rod. Therefore, detection with higher sensitivity can be performed.
[Brief description of the drawings]
FIG. 1 is a system diagram showing a fluidized bed olefin polymerization reaction vessel and its surrounding piping system.
FIG. 2 is a partially enlarged view of a fluidized bed olefin polymerization reaction vessel to which one embodiment of the present invention is applied.
3 is a plan view of the particle swirl type dispersion plate shown in FIG. 2. FIG.
FIG. 4 is a side sectional view of a detection rod and a protective tube in one embodiment of the present invention.
5 is an enlarged sectional view taken along line AA in FIG.
FIG. 6 is a graph showing experimental results when a detection rod is installed and the coil voltage is measured.
FIG. 7 is a side sectional view of a detection rod in another embodiment of the present invention.
[Explanation of symbols]
1 Fluidized bed olefin polymerization reaction vessel (mixed phase vessel)
2 (particle swirl type) dispersion plate 20 agglomerate 21 opening hole 22 cap 51 protective tube 60 detection rod 61 permanent magnet 70 coil (magnetic flux detection means)
F1 Screw fixing point (fulcrum)

Claims (8)

An agglomerate detection method for detecting an agglomerate in a mixed phase container in which a mixed phase is formed and fluidized with gas and powder,
A protective tube with one end fixed to the mixed phase vessel and the other end free is disposed inside the mixed phase vessel, and a detection rod is inserted into the free end of the protective tube and a part thereof is fixed. And
A magnet is attached to the other end of the detection rod, the magnet is placed in a uniform magnetic flux, and the magnet is moved using one point of the detection rod as a fulcrum,
A method for detecting an agglomerate, comprising: measuring a change in the magnetic flux accompanying the movement of the magnet to detect the presence of an agglomerate. An agglomerate detection method for detecting an agglomerate in a mixed phase container in which a mixed phase is formed and fluidized with gas and powder,
Inside the mixed phase container, a detection rod having a part fixed to the mixed phase container and free at one end is arranged,
A magnet is attached to the other end of the detection rod, the magnet is placed in a uniform magnetic flux, and the magnet is moved using one point of the detection rod as a fulcrum,
A method for detecting an agglomerate, comprising: measuring a change in the magnetic flux accompanying the movement of the magnet to detect the presence of an agglomerate. A particle swirl type dispersion plate is disposed at the bottom of the mixed phase container, the circulating gas is blown out horizontally, and the detection rod is installed at a predetermined height above the particle swirl type dispersion plate. The agglomerate detection method according to claim 1 or 2. An agglomerated substance detection device for detecting an agglomerated substance in a mixed phase container in which a mixed phase is formed and fluidized with gas and powder,
A protective tube with one end fixed to the mixed phase vessel and the other end free is disposed inside the mixed phase vessel, and a detection rod is inserted into the free end of the protective tube and a part thereof is fixed. And
At the other end of the detection rod, a magnet that moves in a uniform magnetic flux with one point of the detection rod as a fulcrum is attached,
An agglomerated substance detection apparatus comprising a magnetic flux detection means for detecting a change in the magnetic flux accompanying the movement of the magnet. An agglomerated substance detection device for detecting an agglomerated substance in a mixed phase container in which a mixed phase is formed and fluidized with gas and powder,
Inside the mixed phase container, a detection rod having a part fixed to the mixed phase container and free at one end is arranged,
At the other end of the detection rod, a magnet that moves in a uniform magnetic flux with one point of the detection rod as a fulcrum is attached,
An agglomerated substance detection apparatus comprising a magnetic flux detection means for detecting a change in the magnetic flux accompanying the movement of the magnet. A particle swirl type dispersion plate that blows out a circulating gas in a horizontal direction is disposed at the bottom of the mixed phase container, and the detection rod is installed at a predetermined height above the particle swirl type dispersion plate. Item 6. The agglomerated product detection device according to Item 4 or 5. A fluidized bed olefin polymerization reaction apparatus provided with the agglomerate detection apparatus according to any one of claims 4 to 6. An olefin polymerization method in which the agglomerate in the mixed phase container is detected by the agglomerated substance detection method according to claim 1, and the agglomerate is extracted from the mixed phase container and removed.

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