JP2722969B2 - Fluidized bed reactor gas distributor plate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates are those of ethylene, relates fluidized bed reactor gas distributor plate suitable for gas phase polymerization of olefins such as propylene. The gas distribution plate of the present invention are those which can also be used a stirrer with a fluidized bed reactor.

[0002] Incidentally, described herein as "polymerization" and "polymer" is used to mean, respectively including "homopolymerization" and "copolymerization", and "homopolymer" and "copolymer" .

[0003]

BACKGROUND OF INVENTION Problems to be Solved In recent years,
Production capacity of an olefin polymer per unit transition metal by improving the transition metal catalysts for the polymerization of olefins is dramatically improved, now the catalyst removal operation is omitted after the results polymerization. When using such highly active catalyst,
Since the operation after the polymerization is the simplest, generally it is employed a method of performing the polymerization of olefins in the gas phase. Normally in such gas-phase polymerization, a fluidized bed reactor is often used to promote the polymerization smoothly, increase the olefin or olefin-containing gas introduced from the reactor bottom through the inlet pipe was uniformly dispersed in the gas distributor plate It is, is carried out while being polymerized flow of catalyst particles comprising an olefin polymer and the solid particles in the fluidized bed.

[0004] In this type of fluidized bed reactor, although the porous plate the gas distribution plate have conventionally been widely used, can cause blockage adhering polymer particles to the hole, in this case the polymerization system long-term continuous operation is impossible. Now used as large pore size, the obstruction problem but to some extent resolved, or adhere to the walls polymer particles fall through the holes under the gas distribution plate, the distance between the Mataana and hole , that is, that occurs part bad part of the flow between the pitch become longer hole and the hole. In this case, removal of polymerization heat becomes insufficient, troubles agglomeration or the like of the polymer occurs, is likely to result in shutdown. For these problems improvement has been proposed that mounting various caps on the holes of the gas distribution plate. For example, JP 57-079543 ​​Patent roof-shaped cap in Japanese, triangular pyramid-shaped cap in JP-A-58-154702, the cap using a partition wall in JP-A-58-196205,
Bubble cap in JP 58-201802, JP-Sho 61
In -106608 discloses angles cap have been proposed respectively.

On the other hand, regardless of the magnitude of pore size, gas distribution plate immediately above, it tends to flow failure. Again, trouble agglomeration or the like of the polymer occurs, is likely to result in shutdown and product quality deterioration. As a method for solving this problem,
Remembering directivity in the balloon of the gas from the gas distribution plate, a method of generating a flow of gas to pivot on the gas distribution plate is considered ( "Reaction Engineering fluidized layer" 85, pp Muchiiwao al, 1983 10 month Baifukan published). In addition, JP-A-01-284509
No. In Japanese, side by side horizontal direction balloon cap on a concentric circle, and in JP-A 03-157405, JP-piece structure in which a plate spaced horizontal direction blowout holes in a staggered arrangement combining one or more using a gas dispersion plate having,
Proposed to produce a swirling flow it has been made. However, these gas distribution plate, can not be sufficiently prevented troubles attachment and mass generation of polymer particles, it is not satisfactory to maintain good flow conditions.

[0006] Generally, in large reactors commercial operation scale, gas distribution plate must support the weight of several tens of tons of the polymer particles, it is necessary to support structure under the gas distribution plate, these in the gas distribution plate since holes are irregularly arranged, a simple structure, for example, in the lattice support structure is one of the hole will be blocked because of its structure. Therefore, it has the disadvantage that forced to use a naturally complex structure, for example, concentric support structure.

[0007]

In view of the Means for Solving the Problems] Such circumstances, the present inventors to prevent troubles attachment and mass generation of polymer particles were intensively studied gas distribution plate to maintain good flow conditions result, the pores with a particular arrangement, also found gas distribution plate to solve the problem by making the direction of the cap disposed on the pores with a particular direction, completing the present invention further adding various studies It was.

Namely, the present invention provides a gas distribution plate of the fluidized bed reactor, arranged a number of holes in a square array, contour the gas was blown out horizontally along the distribution plate is streamlined cap was disposed on the pores, the direction is the turning direction of the substantially fluidized bed, moreover holes (10, 2
At the minimum of the square formed by the 0, 30 and 40), approximately the midpoint of the diagonal hole (30) and the other hole of the direction the cap is arranged holes (10) (20 or 40) together in the direction of the (X or Y), the select smaller angle between the circumferential tangent forming the reactor cross section and concentric, further, the outermost holes in the reactor inner wall near the reactor section and located on a circumference forming the concentric circles, the fluidized bed reactor similar to the above cap thereon gas characterized by being arranged to blow outside the tangential direction of the circumference there is provided a gas distribution plate.

[0009] Hereinafter, detailed explanation of the present invention. Gas distribution plate of the present invention, a large number of holes are arranged in a square array with the exception of the reactor near the inner wall section. The distance between the hole and the hole of the case, i.e. pitch opening ratio of the dispersion plate, i.e. the reactor of the opening of the total area or the cap of the opening of the hole to the total area
Ratio of the smaller area of the total area, and the opening of the hole
Surface of the smaller area of the opening portion of the area or cap parts
It is determined from the product. Opening ratio is preferably designed so required pressure loss in the distribution plate to hold the uniform fluidization of the layer radial direction is about 40% of the total pressure loss. Further, the pore size for a concern that clogging of the gas distribution plate is less than five times of the polymer particles having an average diameter preferably is at least equal to 5 times the polymer particles have an average particle size. On the other hand, since the flow failure portion between the pitch is too long holes are formed, it is desirable that as much as possible short. Thus, the aperture ratio is usually 0.5 to 10
% And then, the diameter of the holes is 5 to 30 mm, the pitch of the holes 15
It is in the range of 400mm.

[0010] Figure 1-3 is a view showing a specific example of a cap for use in the present invention, respectively, that a plan view of the cap, b is a side view and c represents the elevational view.
In Figure 1, the cap 2 attached to the top of the hole 1, so as not to inhibit the rotational flow of gas, also a cap outer shape of the streamlined as shown in FIG. 1a or b to not generating the residence portion in the cap upstream, opening 3 as shown in Figure 1c
The outline is, for example, forms a semi-circular and has a structure in which gas is blown from the horizontal direction. In this case, the outline of the opening portion may be a flat triangular or quadrangular. As shown in FIGS. 2 and 3, cap streamlined may was not as tipped front half of the so-called boat. Outer shape streamlined cap is not intended to be limited to those shown in FIGS. If a hole with a cap of this structure, there is no problem of falling of the polymer particles to the gas distribution plate lower than the conventional perforated plate. The cap, for example by arranging for a particular direction of the dispersion plate on the circumferential direction, the circumferential direction of the gas flow on the gas distribution plate during fluidization, i.e. it is swirling flow. This swirling flow, the entire fluidized bed, especially flow-mixing in Sosoko portion becomes good. The addition mass also by centrifugal force as generated some lumps immediately move to the gas distribution plate outer peripheral portion, is pivoted, it can be discharged out of the system while the mass does not grow significantly.

[0011] The cap has a diagonal of a hole gas blown from the holes closest to a one side of the smallest square composed of said hole, one side of the end portion of the hole on the diagonal line It disposed toward substantially to pass through the intermediate portion. That is, the arrangement of the cap is intended to refer to an arrangement of one shown in FIG. 4, the minimum square array of holes is a plan view of a cap disposed at the preferred angle in the direction of the two ways shown in a and b. In other words, the direction of the opening 3 of the cap 2 which is provided over the hole 10 in FIG. 4, i.e. the gas blowing direction is approximately the midpoint of the hole 30 and the hole 20 (X), or nearly middle point of the hole 30 and the hole 40 (Y). The angle θ to dispose the cap 10 to 30 with respect to diagonal lines connecting the holes 10 and holes 30
°, preferably 15 to 25 degrees. Here, the angle θ 1
If you 0-30 °, gas blown from the hole 10,
Passing approximately the midpoint of the hole 30 and the hole 20 or holes 30 and 40 located downstream of the (X or Y). However, the gas distribution plate of the present invention, in order to generate a swirling flow, further gas blowing direction of the cap, as shown in FIG. 5, the minimum through reactor bore 10 arranged in a square cross-section and concentric the tangent of the circumference 4 forming an opening 3 of the cap 2, that may be selected whichever angle theta 'is less formed by the blowing direction of the gas. Figure 5 is a plan view of the cap selecting whichever angle theta 'is small and blowing direction of the circumference of the tangent and the cap through the hole 4. Then, the gas flowing from each hole, the turning direction of the substantially fluidized bed, for example, blown out in the rightward turning direction or left turning direction, as a result,
Generating a swirling flow as a whole.

[0012] Mounting of the cap to the dispersion plate, but is not particularly limited as long as it does not become inhibitor of the swirling flow generated in the dispersion plate, it can be carried out, for example, welding or screws or the like, among them welding is preferable.

[0013] The gas distribution plate of the present invention, the reactor together with new holes in the gas distributor plate the outer peripheral portion is disposed on the circumference near the inner wall, the so gas is blown from the circumferential tangential direction to the outer similar caps and is arranged. As a result, wash away the particles adhering to the inner wall surface gas, and it is possible to promote the flow and mixing in the vicinity of the wall surface Sosoko unit. Hole diameter, the distance between the spacing and hole and the inner wall surface of the hole is not particularly limited, as long as the above effect can be obtained. For example hole diameter, the distance between the spacing and hole and the inner wall surface of the hole, the distance between the square array of holes of diameter about the same as the pitch, for example, the diameter of the hole is 5 to 30 mm, hole spacing and hole and an inner wall surface There is a 15~400mm. Further, 2 preferably blowing direction of the cap (angle theta ", FIG. 6a) is directed in the same turning direction as along the swirling flow by the gas blown from the hole of the square array, and with respect to the circumferential tangential direction to the outer
0 to 70 ° angle may if you have.

[0014] When the inner diameter of the reactor is large, the strength of the plate when an integral product gas distribution plate have a plate thickness very uneconomical, yet hardly fabricated requires several 10 mm. Also, there is a naturally limited to the size of the plate thickness and plate. Figure 6a is a plan view showing an example of the gas dispersing plate of the present invention, to place the holes in a square array and the outermost periphery of the hole is in the reactor near the inner wall,
The holes on the same circumference forming the reactor cross-section and concentrically arranged at equal pitches, the cap 2 is obtained by the particular arrangement as swirling flow as described above is generated. In Figure 6a, the cap is not shown only in part of the dispersion plate, while the other parts are omitted, other portions are also disposed on the entire surface in the same pattern. Gas distribution plate of the present invention, can be comprised of a single plate, as shown in FIG. 6b, combination plate 7 constituting the dispersion plate than two, gas distribution plate 5 having an integral structure
It can also be a. In this case, blowing direction of the cap so as to generate a swirling flow of the gas on the gas distribution plate is determined within the angular range. As the installation method,
Each plate together side by side without a gap, the contact portion, for example, joining by welding or screws or the like, also be fixed by welding or screws or the like thereon by installing a dispersion plate support structure 6 below the gas dispersing plate performed by. Gas distribution plate of the present invention, therefore other than the outer peripheral portion of the hole takes a square array, without holes simply by suitably adjusting the pitch of the holes provided in the gas distributor plate the outer peripheral portion is closed to the support structure, for example grid-like support structure having a simple structure compared to the conventional as shown in Figure 6a can be used.

[0015]

As described in detail above, by using a gas dispersion plate of the present invention, adhesion and the retention of the polymer particles
Agglomerated easily reactor near the inner wall, or improves fluidity and mixing conditions on the gas distribution plate, a stable long-term continuous operation is achieved. The gas distribution plate of the present invention, the reinforcing is easy due to fabrication and support structure compared to conventional gas distribution plate.

[0016]

【Example】

Using a fluidized bed experimental apparatus of Example 1 inner diameter 1000 mm, it was measured the presence of flow failure portion immediately above the gas distribution plate. Gas distribution plate used in the fluidized bed experimental apparatus is in Figure 6a the same type. The gas distribution plate, the diameter of which are arranged in a square array holes 16 mm, the pitch of the holes was set to 66 mm. The diameter of the holes of the gas distribution plate outer peripheral portion close to the inner wall of the reactor is 16m
m, the pitch of the holes was set to 66 mm. Furthermore, blowing direction of the cap on the holes of the gas distribution plate outer peripheral portion close to the inner wall of the reactor is directed in the same direction along the swirl flow by gas blown out from the pores of the square array, and with respect to the circumferential tangential direction and an angle of 30 ° Te. Incidentally, the cap is of the same type as that shown in FIG. 1 was used caps the opening semicircular. Laying polyethylene particles colored on the (average particle diameter 920μm) on one side to the cap is buried, it was charged with the polyethylene particles uncolored thereon to a height of 1.5 m. Nitrogen gas at normal pressure were fed 5 minutes fluidized at a flow rate of 1400 m ³ / hr in this state. Thereafter, the polymer particles withdrawn little by little from above, observation of the position of the colored polyethylene particles remaining on the gas distribution plate, colored throughout the gas distribution plate throughout, including between-reactor near the inner wall of the hole and the hole polyethylene particles was hardly observed.

[0017] In the gas distribution plate of Comparative Example 1 Example 1, the inner wall of the reactor result of performing stoppered in the same manner as in Example 1 to the cap arranged on the circumference in the vicinity, partially colored near the inner wall polyethylene particles was left without being dispersed.

BRIEF DESCRIPTION OF THE DRAWINGS

[1] is a diagram showing a specific example of a cap for use in the present invention, a is a plan view of the cap attached to the top of the hole, b
It is a side view, and c is the elevational view.

Figure 2 is a view showing a specific example of a cap for use in the present invention, a is a plan view of the cap attached to the top of the hole, b
It is a side view, and c is the elevational view.

[Figure 3] is a diagram showing a specific example of a cap for use in the present invention, a is a plan view of the cap attached to the top of the hole, b
It is a side view, and c is the elevational view.

In Figure 4 the smallest square array of holes is a plan view of a cap disposed at the preferred angle in the direction of two ways.

5 is a plan view of a cap arrangement when selecting whichever angle between blowing direction of the circumference of the tangent and the cap through a hole theta 'is smaller in FIG.

[Figure 6] is a plan view showing a specific example of a gas distribution plate of the present invention, a is a plan view of the gas distribution plate cap is shown in a portion of the dispersion plate, b constitute a dispersion plate is a plan view taken out a part of the plate.

DESCRIPTION OF SYMBOLS

1,10,20,30 and 40 ... hole, 2 ... cap, 3 ... cap opening, circumferential forming the through reactor section and concentric with 4 ... hole, 5 ... dispersion plate, 6 ...
Plate constituting the dispersion plate support structure, the 7 ... dispersing plate

Claims (10)

(57) [the claims]
1. 1. A fluidized bed reactor of the gas distribution plate, placed a number of holes in a square array, contour the gas was blown out horizontally along the distributor plate cap of pores is streamlined disposed above said direction is the turning direction of the substantially fluidized bed, yet at the minimum square formed by holes (10, 20, 30 and 40), the direction the cap is disposed hole approximately the midpoint of the diagonal hole (30) and the other hole (10) (20 or 40) (X or Y)
   Together in the direction of, select the smaller angle between the circumferential tangent forming the reactor cross section and concentric, further, the outermost holes In the inner wall of the reactor near, forming the reactor cross section and concentric is on the circumference, fluidized bed reactor gas distribution plate gas similar cap and the thereon is characterized by being arranged to blow outside the tangential direction of the circumference.
2. 2. A cap, gas distribution plate of claim 1, wherein the outline of the opening is a cap that is semicircular.
3. 3. A cap, gas distribution plate of claim 1 wherein the cap has a triangular outline of the opening.
4. 4. A cap, gas distribution plate of claim 1 wherein the cap has a quadrangular outline of the opening.
5. The diameter of 5. arranged in a square array holes 5 to 3
   0 mm, according to claim 1 pitch of the holes is 15~400mm
   Gas distribution plate according.
6. 6. The inner wall of the reactor diameter holes arranged on the same circumference in the vicinity of 5 to 30 mm, the gas distribution plate of claim 1, wherein the distance between the inner wall surface and the hole spacing and hole are 15~400mm .
7. 7. A cap on top of the outermost holes, 2 outwardly with respect to the tangential direction of the circumference forming the reactor cross section and concentric
   0-70 are disposed at an angle of ° formed by Claim 1 gas distribution plate according.
8. 8. Gas distribution plate constitutes the dispersion plate plate (7)
   The least a gas dispersion plate formed as an integral structure in combination two claim 1 gas distribution plate according.
9. 9. gas dispersion plate, the gas distribution plate of claim 1 wherein the gas distribution plate having an agitator in a fluidized layer.
10. 10. A gas distribution plate, placed support structure on the lower surface of the plate (6), the gas distribution plate of claim 1 wherein the gas distribution plate made reinforced.