JPH0779961B2 - Horizontal reactor - Google Patents

Description

TECHNICAL FIELD The present invention relates to a horizontal reactor for carrying out a gas-solid reaction, and in particular, a reaction vessel is divided into three or more zones and is independently divided into at least two zone groups. The present invention relates to a horizontal reactor in which the composition of the gas phase can be controlled and the backflow is prevented in the transfer of particles between the zones.

[Conventional technology]

A horizontal reactor equipped with a stirrer having a horizontal rotating shaft in a cylindrical container is known as a reactor for vapor phase polymerization of polyolefin and the like. These horizontal reactors can be used for complete mixing of powder particles such as polymer particles and catalyst particles, or improvement of heat removal efficiency, and for the residence time distribution of powder particles (RT
In order to narrow the width of D), that is, to make the residence time uniform (hereinafter, abbreviated as RTD improvement), etc., in addition to a stirring means in which a large number of rectangular flat plate paddles are mounted on a horizontal rotating shaft, A reactor capable of continuous treatment is known in which one or more fixed weirs are fixed to the inner wall of the vessel in a direction perpendicular to the rotation axis. (See Japanese Patent Publication No. 59-21321 and Japanese Patent Application No. 61-68771) When the opening of the fixed weir in such a reactor is at the upper part, that is, on the gas phase side, the composition of the gas phase in the reactor is the same for each zone. Become. On the other hand, the average molecular weight of the polymer produced by the gas phase polymerization reaction of polyolefin is influenced by the partial pressure of the molecular weight regulator in the raw material gas. Therefore, when the polymerization is carried out only with gases having the same composition, the average molecular weight of the produced polymer can be controlled, but the molecular weight distribution curve cannot be controlled arbitrarily. Therefore, a method has been proposed in which the inside of the reactor is divided into a plurality of zones by partition walls having openings in the particle layer and the gas composition is controlled in each zone. (Japanese Patent Publication No. 59-21321) [Problems to be solved by the invention] However, the above method has the following problems. That is, since the flat plate paddles suitably used in the horizontal gas phase polymerization reactor generate thrust in both directions on the rotation axis, the flat plate paddles before and after the partition wall having the openings in the particle layer pass through the openings. The particles are moved in the forward and reverse directions. Therefore, particles that stay in the reactor for a long time will be present, and the RTD cannot be improved. Therefore, it is difficult to control the produced polymer to have desired properties. Furthermore, since it is difficult for the granular material to transmit the pressure in the horizontal direction, even if there is a difference in the particle layer level before and after the partition wall, the amount of particles passing through the openings in the particle layer is less likely to change accordingly, and the partition wall The particle layer level was not stable in the front and back zones, and continuous operation could not be performed in a steady state for a long time. The present invention has been made to solve the above problems, and it is possible to freely control the gas component partial pressure in two or more zone groups in the reactor, and further improve the RTD for a long time. It is an object of the present invention to provide a horizontal reactor for gas-solid reaction which can be continuously operated.

[Means for solving problems]

A cylindrical container having a horizontal central axis, a stirrer having a rotating shaft arranged to coincide with the horizontal central axis, and a supply port and a product for a stirring object respectively arranged at both ends of the cylindrical container. And two or more partition walls that are arranged perpendicular to the rotation axis and have an opening at the bottom and divide the inside of the cylindrical container into three or more zones, and the three or more zones are gas. Which is connected to two or more independent gas circulation systems for circulating and supplying the gas, and a horizontal reaction in which a gas phase-solid phase reaction is performed in a state where the particle layer existing in the cylindrical container fills the opening of the partition wall. In the vessel, the stirrer includes a plurality of paddle sets in which one or more flat plate paddles are attached at predetermined positions in the axial direction of the rotary shaft, and in particular, two sets of paired paddles sandwiching the partition wall form an opposing pair. The paddle group has the following conditions (i) to (vi) for each pair. Satisfied, in relation to the adjacent pairs so as to satisfy the condition (vii).

(I) The paddle widths W of the two paddle groups are equal.

(Ii) 10 ° ≦ β ≦ 45 ° (iii) D / 100 ≦ l ₁ ≦ D / 20 (iv) l ₂ / l ₁ ≧ 1 (v) 1 ≦ S ₂ / S ₁ ≦ 3 (vi) α ≧ 90 ° (vii) Between all pairs of adjacent paddle sets, l _{1 s} , l _{2 s} , S _{1 s} , S _{2 s} , W s are equal to each other.

The symbols in the above formula have the following meanings.

β: The angle of advance of the paddle on the product extraction side with respect to the paddle on the supply side of the stirring target D: Inner diameter of the cylindrical container l ₁ : Clearance between the inner wall of the container and the tip of the paddle on the supply target of stirring target l ₂ : Inner wall of the container To the tip of the product extraction side paddle S ₁ : Clearance between the paddle on the object supply side and partition wall S ₂ : Clearance between the paddle on the product extraction side and partition wall α: Paddle pad for the object to be stirred Leading angle in the rotation direction with respect to the product extraction side paddle of [Operation] The operation of the present invention will be described with reference to the drawings. 2 to 4 are views showing the positional relationship of the flat plate paddles before and after the partition wall and the position of the surface of the granular material when the present invention is carried out, and FIG. 1A showing the cross section of the embodiment. Corresponds to the -A cross section. The cylindrical container 1 is divided by the partition walls 2, 2 ', 2 "into four zones from the upstream side of the granular material 3 to the first, second, third and fourth zones. There are two flat plate paddles 4 of the paddle set, and these are fixed to the rotary shaft 5 at an interval of 180. When the rotary shaft 5 rotates in the direction of the arrow, the position of the granular material surface will be the position of the flat plate paddles 4 and 4. Accordingly, the range indicated by the solid line and the alternate long and short dash line in Fig. 2 is changed. In this state, since the amount of gas passing through the opening is small, it is possible to maintain different gas partial pressure components in the upstream side zone and the downstream side zone. When moving, the granular material is removed in the rear with respect to the rotation direction of the flat plate paddle, and a rough filling part is created. On the contrary, the granular material is pushed in the front and side of the flat plate paddle to form a densely packed portion, so that when one of the adjacent flat plate paddles advances in the rotation direction, the granular material is delayed. The pressure from the flat plate paddle causes it to flow backward of the flat plate paddle and move in the axial direction. This action does not occur when the advance angle α or β exceeds 90 °, and 10 ° ≦ α ≦ 45 ° or 10 ° ≦ β
In the range of ≤45 °, the above action is strongly generated. Therefore, if the number of paddles in the paddle group before and after the partition wall is two and the lead angle β of the downstream paddle is in the range of 10 ° ≤ β ≤ 45 ° as shown in the figure, the lead angle of the upstream paddle is α is 135 ° ≦ α ≦ 170
The rotation of the paddle causes the particles to be thrust from the upstream side to the downstream side, but almost no thrust in the reverse direction is generated. Therefore, by appropriately determining the area of the opening, the required flow of particles in the downstream direction can be secured and the flow of particles in the reverse direction can be substantially eliminated. When the number of paddles in the paddle group is four or more, the advance angle α of the upstream side paddle becomes 90 ° or less, and therefore the flow of particles in the upstream direction also occurs, which is not preferable. Further, when the number of revolutions is low, when the fluidity of the granular material is poor, and the like, the fluctuation range of the rough filling portion is large. For example, when the rotation speed is low, the coarse filling portion becomes small and the fluctuation rate of the amount of movement of particles from the upstream side to the downstream side becomes large, so that it becomes difficult to control the amount of powder particles held in the upstream zone.
In such a case, as a result of various experiments, if the paddle width of the paddle group before and after the partition wall is the same, and if l ₂ / l ₁ ≧ 1 and S ₂ / S ₁ ≧ 1, the powder particles from the upstream side to the downstream side It was confirmed that the movement was smooth.

When many experiments were conducted to find out what range should be set for l _{1 with} respect to the inner diameter D of the container, the appropriate range for l ₁ is D / 100 ≤ l ₁ ≤ D / 20 I understood. Also S ₂ /
If S ₁ is too large, the coarse filling part region generated by the downstream paddle does not reach the opening and the effect of the present invention is not obtained easily, but the stirring state of the powder or granules in the clearance S ₂ part deteriorates, and if it is unreasonable Becomes dead space. Also in this respect, 1 ≦ S ₂ / S ₁ ≦ 3 was obtained as an appropriate range by experiments.

Further, it has been found that it is preferable that l _{1 s} , l _{2 s} , S _{1 s} , S _{2 s} , and W s are equal to each other among all pairs of adjacent paddle sets.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings. As shown in FIGS. 1 to 4, a rotary shaft 5 is arranged so as to match the central axis of the cylindrical container 1, and flat plate paddles 4 and 4 are fixed to the rotary shaft 5 at a plurality of positions in the axial direction. Multiple paddle groups have been created. The stirrer 7 is configured in this way. In FIG. 1, the position of the flat plate paddle in the rotation direction is appropriately changed and shown for easy understanding. The cylindrical container 1 is partitioned by partition walls 2, 2 ', 2 ", and a first zone 8a, a second zone 8b, a third zone 8c, and a fourth zone 8d are formed from the upstream side. 2 ″ has an opening 6 at the bottom.
The first zone 8a is provided with a stirring object supply port 10, and the fourth zone 8d is provided with a product outlet 11. The supply port for the raw material gas and the coolant and the discharge port for the unreacted gas are not shown in FIG. The number of flat plate paddles in the paddle set having the above configuration is not particularly limited, but it is preferable that the paddle set before and after the partition wall has three or less as described above. The ratio L / D of the length L to the diameter D of the cylindrical container 1 is preferably 1.0 or more. The openings 6 of the partition walls 2, 2 ', 2 "
Is preferably in the range of 135 ° to 270 ° in the direction of rotation of the axis of rotation with respect to the upward direction of the vertical line in the plane perpendicular to the axis of rotation, and the opening is always buried in the particle layer. It is said that The opening 6 shown in FIGS. 2 to 4 is in the range of 180 ° to 225 ° in the rotational direction, and the width X of the opening is X.
Is about 1/6 of the container diameter. With such an opening shape, the state in which the opening is always buried in the particle layer is maintained even if the amount of powder or granules held is 20% of the reactor volume.

When carrying out, for example, gas phase polymerization of olefins using the horizontal reactor configured as described above, independent source gas and coolant circulation systems are connected to the respective zones or zone groups, and the source gas and coolant are connected. Is circulated in the above zone and a catalyst containing a transition metal compound is supplied from an agitation target supply port 10, and the granular material 3 as a polymerization product is agitated by a stirrer 7 and moved to the downstream side to discharge the product
It is extracted from 11. At this time, it is preferable to rotate the stirrer 7 so that the Froude number Fr is in the range of 0.05 to 3.0, particularly 0.2 to 2.0. Froude number is the formula Fr ＝
Defined in Rw ² / g.

Here, R is the length from the center of the rotation axis to the tip of the paddle, w is the angular velocity radian / sec, g is the gravitational acceleration.

Further, it is preferable that the amount of the powder or granules in the container is 20 to 80% by volume for continuous treatment.

When the product is a polymer, exemplifying its type,
Ethylene polymer, propylene polymer, butene polymer, ethylene propylene polymer, ethylene-butene 1
Copolymers, propylene-butene 1 copolymers, propylene-butene 1-ethylene copolymers and the like.

A process for carrying out vapor phase polymerization of polypropylene using the horizontal reactor as described above is shown in FIG. The unreacted gas propylene gas discharged from the first and second zones 8a, 8b of the horizontal reactor is introduced into the cyclone separator 30 through the exhaust gas line 20. The propylene gas from which entrained particles have been removed by the cyclone separator 30 is cooled by the condenser 21 and partially liquefied. Propylene in a gas-liquid mixed state is guided from the condenser 21 to the separator 22 where it is gas-liquid separated. The propylene gas extracted from the separator 22 is blower 23
As a result, the gas is blown into the first and second zones 8a, 8b from the raw material gas supply port 24. On the other hand, the liquefied propylene extracted from the separator 22 is sent by a pump 25 to a coolant injection port 27 to
1, injected into the second zones 8a, 8b. Hydrogen gas and propylene gas are supplied to the gas circulation system through a hydrogen gas supply line 28 and a propylene gas supply line 29, respectively, and the supply amount of hydrogen gas is controlled by the hydrogen concentration in the exhaust gas line 20. The gas circulation systems in the third and fourth zones are configured in the same manner as in the above side zone except for the cyclone separator 30. In the figure, corresponding components are shown with the same numbers and dashes.

Next, the data obtained by carrying out the present invention will be specifically shown. The diameter D of the cylindrical container 1 is 430 mm, the length L is 1320 mm, the diameter of the rotating shaft is 110 mm, the width of the flat paddle is 50 mm, the clearance is 1 ₁ = 5 mm, l ₂ = 5 mm, S ₁ = 5 mm, S ₂ = 10 mm. And
The number of flat plate paddles in each paddle group was two, and the lead angle between the paddle groups before and after the bulkhead was 90 °.
Partitions 2, 2 ', 2 "are arranged at positions where the cylindrical container 1 is divided into four, and the opening has the same shape as that shown in Fig. 2 to Fig. 4 and the width X is 30 mm. The lead angle β of the flat plate paddle in the downstream zone between the paddle groups before and after 2,2 ′, 2 ″ was 45 °, and the lead angle α of the flat plate paddle in the upstream zone was 135 °. 60% by volume of inert polypropylene was charged into the cylindrical container 1 in advance, and the rotating shaft 5 was rotated at 60 rpm.
It was rotated at (Fr = 0.826) and the inside of the cylindrical container 1 was stabilized under the polymerization conditions of a temperature of 70 ° C and a pressure of 22 kg / cm ² G. After the inside of the cylindrical container has stabilized, the catalyst is supplied from the stirring object supply port 10 at about 1.5 g / hr.
Was supplied at a rate of and the polymerization reaction was continuously carried out. The amount of powder and granules in the cylindrical container during the steady state of the reaction is about 65% by volume of the container volume.
Polypropylene was produced at 15 kg / hr. The second zone 8
A discharge port 31 was provided at the bottom of b, and powder particles were sampled from there. Polypropylene was produced for two grades, and the average hydrogen gas molar ratio to unreacted propylene gas during production of grade 1 was 0.045 in the exhaust gas line 20 and 0.001 in the exhaust gas line 20 '. In the production of grade 2, the exhaust gas line 20 was 0.015 and the exhaust gas line 20 'was 0.005.

The polymer test results of the obtained polypropylene are shown in Table 1. MFR in Table 1 (Melt flow rate, measurement method JIS K675
The A value in 8) is the MFR value in the polypropylene sampled from the bottom outlet 31 of the second zone, and the B value is the product outlet 1
It is the MFR value of polypropylene taken from 1. The Q value is
GPC (Japan Waters Liquid Chromatograph GPC150c)
The value obtained by dividing the weight average molecular weight obtained by
The larger the value, the better the flow properties. Furthermore, the F value is the MFR when the load is 5 times (10.8kg) the load (usually 2.16kg load) at the time of MFR measurement.
It is a value obtained by dividing the value by the MFR value under the normal load (the above B value). As with the Q value, the larger the F value, the better the flow characteristics.

In addition, when each polymerization amount in each zone was weighed at the completion of the polymerization reaction in the examples, the first zone was 12.2 kg and the second zone was 1 kg.
The weight was 2.1 kg, the third zone was 12.6 kg, and the fourth zone was 13.0 kg. The amount of holding in each zone is almost the same, and it was found that the amount of holding is controlled smoothly.

[Comparative example]

Polymerization reaction was carried out under the same process and the same polymerization conditions as in Example except that the three partition walls in Example were removed. However, with respect to the hydrogen supply amount of each hydrogen gas supply line 28, 28 ', the grade 1 and grade 2 hydrogen supply ratios of the examples were maintained and produced with reference to the actual results of the examples.

The polymer test results of the obtained polypropylene are shown in Table 2. In Table 2, grade 3 is polypropylene produced with a hydrogen supply amount corresponding to grade 1, and grade 4 is polypropylene produced with a hydrogen supply amount corresponding to grade 2.

It can be seen from Tables 1 and 2 that grade 1 and grade 2 are polypropylenes having a larger MFR difference than grades 3 and 4, have a large Q value and F value, and have good flow characteristics.

〔The invention's effect〕

The horizontal reactor according to the present invention is divided into three or more zones by partition walls so that different atmospheres can be controlled between two or more zone groups, and particles can be smoothly moved between the zones without backflow. As a result, a product having an arbitrary molecular weight distribution curve can be obtained, and, for example, in the case of polypropylene, the flow characteristics can be improved. Further, since the RTD is improved, the amount of catalyst consumed is small, and the particles move smoothly between the partition walls, which enables continuous operation for a long period of time.

[Brief description of drawings]

FIG. 1 is a longitudinal section of a horizontal reactor showing an embodiment of the present invention, FIGS. 2 to 4 are sectional views taken along the line AA in FIG. 1, and FIG. 4 is a rotary shaft in FIG. 5 shows a state in which 5 is rotated 90 °. FIG. 5 is a systematic diagram of a process using the horizontal reactor according to the embodiment of the present invention. 1 ... Cylindrical container, 2 ... Partition wall, 3 ... Powder and granular material, 4 ...
Flat paddle, 5 ... Rotating shaft, 6 ... Opening part, 7 ... Stirrer, 8a, 8b, 8c, 8d ... 1st, 2nd, 3rd, 4th zone, 10 ...
Stirring object supply port, 11 …… Product discharge port.

Claims (3)

[Claims] 1. A cylindrical container having a horizontal central axis, a stirrer having a rotary shaft arranged to coincide with the horizontal central axis, and stirring objects arranged at both ends of the cylindrical container. A supply port and a discharge port for the product; and two or more partition walls that are arranged perpendicular to the rotation axis and have an opening at the bottom to divide the inside of the cylindrical container into three or more zones. The above zones are connected to two or more independent gas circulation systems that circulate and supply gas, and the gas phase-solid phase in a state where the particle layer existing in the cylindrical container fills the opening of the partition wall. In the horizontal reactor for carrying out the reaction, the agitator includes a plurality of paddle groups in which one or more flat plate paddles are attached at predetermined positions in the axial direction of the rotating shaft, and particularly, the agitator forms opposing pairs sandwiching the partition wall. The two paddle groups have the following (i) to (vi) for each pair. Satisfies the condition, horizontal reactor which satisfies the condition (vii) in relation to the adjacent pair. (I) The paddle widths W of the two paddle groups are equal. (Ii) 10 ° ≦ β ≦ 45 ° (iii) D / 100 ≦ l ₁ ≦ D / 20 (iv) l ₂ / l ₁ ≧ 1 (v) 1 ≦ S ₂ / S ₁ ≦ 3 (vi) α ≧ 90 ° (vii) Between all pairs of adjacent paddle sets, l _{1 s} , l _{2 s} , S _{1 s} , S _{2 s} , W s are equal to each other. The symbols in the above formula have the following meanings. β: The angle of advance of the paddle on the product extraction side with respect to the paddle on the supply side of the stirring target D: Inner diameter of the cylindrical container l ₁ : Clearance between the inner wall of the container and the tip of the paddle on the supply target of stirring target l ₂ : Inner wall of the container To the tip of the product extraction side paddle S ₁ : Clearance between the paddle on the object supply side and partition wall S ₂ : Clearance between the paddle on the product extraction side and partition wall α: Paddle pad for the object to be stirred Angle of advance in the direction of rotation with respect to the product extraction side paddle 2. The horizontal reactor according to claim 1, wherein the supply port of the stirring object provided at one end of the cylindrical container is a supply port of a catalyst for causing a polymerization reaction. 3. The gas phase-solid phase reaction is an olefin polymerization reaction, and the gas circulated and supplied to the gas circulation system contains a raw material gas, hydrogen gas and a liquefied gas as a coolant. Alternatively, the horizontal reactor according to item 2.