JPH0779960B2 - Horizontal reactor - Google Patents

Description

TECHNICAL FIELD The present invention relates to a horizontal reactor for performing a gas-solid reaction, and in particular, a reaction vessel is divided into two zones, and the composition of the gas phase is independent in each zone. Is a controllable reactor and yet prevents backflow in the transfer of particles between the two 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 good axis, 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 thrust is generated in both directions on the flat plate paddle rotation axis that is preferably used in the horizontal gas phase polymerization reactor, the particles are passed through the openings by the flat plate paddles before and after the partition wall having the openings in the particle layer. Are moved forward and backward. 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 was not possible in a steady state for a long time.
The present invention has been made to solve the above problems,
Provided is a horizontal reactor for gas phase-solid phase reaction, in which the partial pressure of the carburizing component can be freely controlled in two zones in the reactor, the RTD is improved, and long-term continuous operation is possible. The purpose is to

[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 supply port for a stirring object which are respectively disposed at both ends of the cylindrical container. The outlet and outlet for the object, and a partition wall that is arranged perpendicular to the rotation axis and has an opening at the bottom and divides the inside of the cylindrical container into two zones, and the two zones circulate and supply gas, respectively. In a horizontal reactor that is connected to two independent gas circulation systems and performs a gas-solid reaction in a state where a particle layer existing in the cylindrical container fills the opening of the partition wall, the stirrer is rotated. 1 at a predetermined position in the axial direction of the shaft
A plurality of paddle sets having at least one flat plate paddle attached thereto are included, and in particular, two paddle sets facing each other with the partition wall interposed therebetween satisfy the following conditions.

(I) The width of the paddles of the two paddle groups is 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 ° 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 a partition wall 2 into an upstream side zone (backward side of the drawing) and a downstream side zone (front side of the drawing) of the powder or granular material 3. In the case shown in the figure, there are two flat plate paddles 4 in one paddle set, which are fixed to the rotary shaft 5 at intervals of 180 °. When the rotary shaft 5 rotates in the direction of the arrow, the position of the surface of the granular material changes within the range shown by the solid line and the alternate long and short dash line in FIG. 2 depending on the positions of the flat plate paddles 4, 4. However, since the slope is always a left-down slope, if the opening 6 of the partition wall is arranged at the lower right, the opening can always be kept buried in the granular material. In this state, the amount of gas passing through the opening is small, so that it is possible to maintain different gas partial pressure components in the upstream zone and the downstream zone. When the flat plate paddle moves in the powder or granular material, the powder or granular material is removed in the rear direction with respect to the rotation direction of the flat plate paddle, and a rough filling portion is formed. On the contrary, the granular material is pushed to the front and side of the flat plate paddle to form a densely packed portion. Therefore, when one of the adjacent flat plate paddles is advancing in the rotation direction more than the other, the granular material flows behind the flat plate paddle advancing by the pressure of the delayed flat plate paddle and moves in the axial direction. This effect is due to the advance angle α or β
It does not occur above 90 °. Also, 10 ° ≦ α ≦ 45 ° or
In the range of 10 ° ≦ β ≦ 45 °, the above-mentioned action is strongly generated. Therefore, as shown in the figure, the number of paddles in the paddle group before and after the partition wall is 2
If the lead angle β of the downstream paddle is in the range of 10 ° ≦ β ≦ 45 °, the lead angle α of the upstream paddle is 135 ° ≦
α ≦ 170 °, and due to the rotation of the paddle, the particles receive thrust from the upstream side to the downstream side, but thrust in the opposite direction is hardly generated. Therefore, by setting the area of the opening appropriately,
The required downstream particle flow can be ensured and the reverse particle flow 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 are 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 part, and it is difficult to obtain the effect of the present invention, and the stirring state of the granular material in the clearance S ₂ part deteriorates. Dead space when it hits. Also in this respect, 1 ≦ S ₂ / S ₁ ≦ 3 was obtained as an appropriate range by experiments.

〔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 a partition wall 2 at the central portion to form an upstream zone 8 and a downstream zone 9. The partition 2 has an opening 6 at the bottom. In the upstream zone 8, the stirring object supply port 10
However, a product outlet 11 is provided in the downstream zone 9. 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. Flow L for diameter D of cylindrical container 1
The ratio L / D of is preferably 1.0 or more. The partition wall 2
The opening 6 is preferably in the range of 135 ° to 270 ° in the rotation direction of the rotation axis with respect to the vertical direction of the vertical line in the plane perpendicular to the rotation axis, and the opening is always buried in the particle layer. The shape is set to the state. 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 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 an olefin using the horizontal reactor configured in this manner, independent raw material gas and coolant circulation system are connected to the upstream side zone and the downstream side zone, respectively. The cooling agent is circulated in the above zone and a catalyst containing a transition metal compound is supplied from a supply port 10 to be agitated, and a granular product 3 which is a polymerization product.
Is stirred by the stirrer 7, moved to the downstream side, and discharged from the product discharge port 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 by Rw ² / g.

Here, R is the length from the center of the rotating shaft 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 propylene gas discharged from the upstream zone 8 of the horizontal reactor passes through the exhaust gas line 20 and is a cyclone separator.
Guided to 30. 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 blown into the upstream zone 8 from the raw material gas supply port 24 by the blower 23.
On the other hand, the liquefied propylene extracted from the separator 22 is sent by the pump 25 and injected into the upstream side zone from the coolant injection port 27. 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 system in the downstream side zone is configured similarly to that in the above side zone except that the cyclone separator 30 is excluded. 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 cylindrical container 1 has a diameter D of 430 mm, a length L of 1320 mm, a rotary shaft diameter of 110 mm, and a flat paddle width of 50 mm. Clearances are l 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 °.
A partition 2 is arranged at a position where the cylindrical container 1 is divided into two equal parts, and the opening has the same shape as that shown in FIGS. 2 to 4 and the width X is 30 mm.
And The lead angle β of the flat plate paddle in the downstream zone between the paddle groups before and after the partition wall 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 in advance in the cylindrical container 1 and the rotary shaft 5 was rotated at a rotation speed of 60 rpm (Fr = 0.826) to a temperature of 70 ° C. and a pressure of 22 Kg / cm ² G under polymerization conditions. The inside of the cylindrical container 1 was stabilized. After the inside of the cylindrical container is stabilized, the catalyst is supplied from the stirring object supply port 10 at a rate of about 1.5 g / hr,
The polymerization reaction was continuously carried out. In the steady state of the reaction, the amount of powdered granules in the cylindrical container was about 65% by volume with respect to the container volume, and polypropylene was produced from the product outlet 11 at an average pace of 15 Kg / hr. A discharge port 31 was provided at the bottom of the upstream zone 8 to sample the powder and granules.
Polypropylene is produced for two grades, of which the average molar ratio of hydrogen gas to unreacted propylene gas during production of grade 1 is 20
Was 0.045 and the exhaust gas line 20 'was 0.001. Also, at the time of production of grade 2, 0.01 in the exhaust gas line 20
5, was 0.005 in the exhaust gas line 20 '.

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 of the polypropylene sampled from the bottom outlet 31 of the upstream zone, and the B value is the MFR value of the polypropylene sampled from the product outlet 11. Also Q
Value is GPC (Japan Waters Liquid Chromatograph GP150
The value obtained by dividing the weight average molecular weight obtained in c) by the number average molecular weight represents the flow characteristics of the polymer when melted. The larger the Q value, the better the flow characteristics. Furthermore F
The value is the load at the time of the above MFR measurement (usually 2.16K
g when the load is 5 times (10.8Kg)
It is a value obtained by dividing the FR 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 the amount of each of the upstream zone and the downstream zone was measured at the completion of the polymerization reaction in the example, the upstream zone was
24.8Kg, the downstream zone was 25.3Kg. The amount of holding in the upstream zone and the amount of holding in the downstream zone are almost the same, and it was found that the holding amount 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 partition wall 2 in Example was removed. However, regarding the hydrogen supply amount of each hydrogen gas supply line 28, 28 ', referring to the actual results of the embodiment, grade 1 and grade 2 of the embodiment
It was produced by maintaining the hydrogen supply ratio of.

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〕

Since the horizontal reactor according to the present invention is divided into zones having two different atmospheres by partition walls and particles can be smoothly moved between the two zones without backflow, a product having an arbitrary molecular weight distribution curve can be obtained. 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 THE DRAWINGS FIG. 1 is a vertical section of a horizontal reactor showing an embodiment of the present invention, and FIGS. 2 to 4 are sectional views taken along the line AA in FIG. Shows a state in which the rotary shaft 5 in FIG. 3 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, 8 ... Upstream side zone, 9 ... Downstream side zone, 10 ...
Stirring object supply port, 11 …… Product discharge port.

Claims (3)

[Claims] 1. A cylindrical container having a horizontal central axis, an agitator having a rotary shaft arranged to coincide with the horizontal central axis, and an object to be agitated respectively arranged at both ends of the cylindrical container. It consists of a supply port and a discharge port for the product, and a partition wall that is arranged perpendicular to the rotation axis and has an opening at the bottom and divides the inside of the cylindrical container into two zones, each of which circulates a gas. And a horizontal reactor that is connected to two independent gas circulation systems and that performs a gas-solid reaction in a state where a particle layer existing in the cylindrical container fills the opening of the partition wall, 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 rotating shaft, and in particular, two paddle sets facing each other across the partition wall satisfy the following conditions. Horizontal reactor characterized by. (I) The width of the paddles of the two paddle groups is 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 ° 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 clearance S ₁ of the tip of the product extraction side paddle: clearance between the stirring object supply side of the paddle of the partition wall S _2: clearance of product withdrawing side of the paddle and the partition alpha: stirring object supply paddle 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. The horizontal reactor according to item 2.