JP2006142297A - Method and machine for packing catalyst - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for packing a catalyst, by which the catalyst can simultaneously be packed uniformly in a plurality of reaction tubes. <P>SOLUTION: This method is used for packing the granular catalyst from above in the plurality of reaction tubes of a fixed bed multitubular reactor so that the dispersion of the packing speeds when the catalyst is packed in reaction tubes is ≤±20%. In order to adjust the dispersion of the packing speeds to ≤±20%, for example, a catalyst conveying line is formed under each of a plurality of catalyst-charged hoppers, the catalyst dropped from any of hoppers is conveyed to an upper end opening of the corresponding reaction tube along the corresponding catalyst conveying line and the amount of the catalyst to be charged in each of hoppers is measured with ±5% precision when the catalyst is packed in each of reaction tubes from the upper end opening. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a catalyst filling method and a catalyst filling machine for filling a fixed bed multitubular reactor applied to a gas phase catalytic oxidation reaction using a catalyst.

  Generally, in the production of chlorine, hydrogen chloride contained in the produced chlorine gas is subjected to catalytic oxidation in the presence of a catalyst using a gas containing oxygen. Since this oxidation reaction is an exothermic reaction, the reaction is performed using, for example, a fixed bed multi-tube heat exchange reactor in which a large number of reaction tubes are filled with a granular catalyst.

  In such a fixed bed multitubular reactor, the catalyst filling state is as small as possible so that no bridge is formed between the catalysts in the filling process of the catalyst into each reaction tube, and the pressure loss measured after filling is reduced. It needs to be uniform.

  Therefore, Patent Document 1 describes that, in a fixed bed multitubular reactor, each reaction tube is filled with a catalyst that is a solid granular material in a filling time of 30 seconds or more per liter. However, when a plurality of reaction tubes are simultaneously filled with a catalyst using a catalyst filling machine or the like, it is difficult to reduce the variation in pressure loss Δp in a large number of reaction tubes only by defining the filling speed.

  For example, Patent Document 2 describes a catalyst filling machine in which a catalyst is put in a small hopper and catalyst particles are dropped into a reaction tube while applying vibration. Although this method is simple, unevenness in the catalyst supply rate due to vibration tends to occur, resulting in a difference in the catalyst filling rate for each reaction tube. As a result, the bulk density of the catalyst in each reaction tube varies, and as a result, the pressure loss Δp varies.

JP 2002-306953 A Japanese Examined Patent Publication No. 47-11484

  An object of the present invention is to provide a catalyst filling method capable of simultaneously and uniformly filling a plurality of reaction tubes, and a catalyst filling machine suitable for use in the method.

  As a result of intensive investigations to solve the above problems, the present inventors have reduced the variation in the filling speed of each reaction tube, thereby reducing the variation in the bulk density of the catalyst packed in each reaction tube. The present inventors have found a new fact that a uniform catalyst can be charged simultaneously into the reaction tubes and have completed the present invention.

  That is, in the catalyst filling method of the present invention, when filling a large number of reaction tubes provided in a fixed bed multitubular reactor with a granular catalyst from above, variation in the filling rate of each reaction tube is ± 20% or less. It is characterized by filling a catalyst so that it becomes.

  As a specific example for making the variation in the filling speed within the above range, a catalyst transport row is formed for each hopper under a plurality of hoppers into which the catalyst is charged, and the catalyst dropped from each hopper is placed in each catalyst transport row. And a catalyst filling method in which the amount of catalyst charged into each hopper is measured with an accuracy within ± 5% when the catalyst is fed into the upper end opening of the reaction tube and charged into the reaction tube from the upper end opening.

  A catalyst filling machine suitable for applying the catalyst filling method of the present invention is a method of simultaneously filling a plurality of reaction tubes with particulate catalyst from above, and a catalyst corresponding to the plurality of reaction tubes. A plurality of hoppers to be charged are provided, and a catalyst transport row is formed for each hopper under the hopper, and the catalyst dropped from each hopper passes through each catalyst transport row and above each reaction tube. It is characterized by being conveyed and filled.

  The catalyst transport row includes a conveyor that carries the catalyst flowing down from the hopper and transports it to the reaction tube, and a plurality of partition walls that are installed on the upper surface of the conveyor to partition the transport path for each reaction tube. It is good to have.

  According to the present invention, by setting the variation in the filling speed of each reaction tube to a predetermined value or less, the variation in the bulk density of the catalyst in each reaction tube is reduced, and the reaction tube is uniformly distributed to a plurality of reaction tubes at the same time. Since the catalyst can be charged, the variation in the pressure loss between the reaction tubes is reduced, and the pressure loss can be made uniform.

  1 and 2 show an example of a catalyst filling machine suitable for use in the catalyst filling method of the present invention. This catalyst filling machine is held by a position changing mechanism (not shown) such as a carriage, and is configured so that the position can be changed in the direction in which the reaction tubes 2 are arranged.

  As shown in FIG. 1 and FIG. 2, this catalyst filling machine carries a plurality of independent hoppers 1a, 1b,... 1x that store particulate catalysts, and a catalyst that flows down from each hopper 1a, 1b,. A belt conveyor 3 is provided that is fed to the reaction tube 2 from above (the direction of catalyst transportation is indicated by an arrow A in FIG. 2). On the upper surface of the belt conveyor 3, a plurality of partition walls 6 for partitioning into a width corresponding to the plurality of reaction tubes 2 arranged in the transport width direction and forming a transport path for each reaction tube are installed. As a result, a catalyst transport row is formed for each reaction tube 2.

  In order to guide the catalyst from the conveyance end portion of the belt conveyor 3 to each reaction tube 2, a chute 8 is provided for each catalyst conveyance row, and a hose 9 is connected to the lower end of the chute 8. A charging hopper 10 is inserted into the upper end of each reaction tube 2, and the lower end of the hose 9 faces the hopper 10. It is preferable that the number of hoppers 1a, 1b... 1x included in one catalyst filling machine and the corresponding catalyst transport rows is 1 to 50, more preferably 5 to 30.

  A catalyst is supplied to the plurality of reaction tubes 2 from the plurality of hoppers 1a, 1b,... 1x through the catalyst transport rows, and when this supply is completed, the position of the catalyst filling machine is changed by the operation of the position changing mechanism. A catalyst is supplied to a plurality of reaction tubes 2, and the catalyst is supplied to each of a plurality of reaction tubes 2 by repeating this process.

The plurality of hoppers 1a, 1b... 1x are formed independently, and are arranged in parallel. That is, each of the hoppers 1a, 1b... 1x includes a rear wall 11, a side wall 12, and a front wall 13, and the rear wall 11 is inclined so that the distance from the front wall 13 is gradually decreased downward. . The inclination angle of the rear wall 11 is larger (steep) than the repose angle of the catalyst. On the other hand, the side wall 12 and the front wall 13 are substantially vertical.
The rear wall 11 and the side wall 12 are formed, for example, by bending a single metal plate, and the side wall 12 and the front wall 13 are integrally joined by welding. Since the metal plate is formed by bending, there is no seam such as welding at the boundary between the rear wall 11 and the side wall 12, and the inner surface of the boundary is curved. Therefore, the catalyst falls smoothly from within the hoppers 1a, 1b... 1x, and the layer height T of the catalyst transport can be made constant.

  Further, a damper 14 is provided below each hopper 1a, 1b,... 1x. The damper 14 is opened (as shown in FIGS. 1 and 2), the catalyst is transported, and when the transport is finished, the damper 14 is It is designed to be closed (indicated by a dashed line in FIG. 1). The opening / closing mechanism of the damper 14 may be, for example, an opening / closing plate that is driven to open / close by compressed air as shown in FIG. 2, or a sliding plate that slides up and down.

  The damper 14 is operated as follows. (1) With the damper 14 closed, a predetermined amount (for example, one reaction tube) of catalyst is supplied to each hopper 1a, 1b... 1x, and (2) the belt conveyor 3 is driven (this drive is (3) The damper 14 is opened and the catalyst is supplied to the reaction tube 2.

  A layer thickness setting plate 7 (layer thickness setting section) is provided in the catalyst transport row for each hopper 1a, 1b,. By adjusting the height of the layer thickness setting plate 7, the layer thickness T of the transport catalyst can be freely set. The layer thickness T can be adjusted to a size suitable for the reaction tube 2. The height of the layer thickness setting plate 7 can be adjusted by any means. For example, a long long hole is provided in the layer thickness setting plate 7 and a bolt for inserting the long hole is not shown. Thus, the layer thickness setting plate 7 can be supported so as to be adjustable in height.

  The catalyst flowed down from the hoppers 1a, 1b... 1x and placed on the belt conveyor 3 is received by the lower end portion of the layer thickness setting plate 7 at the upper end side as the belt conveyor 3 is conveyed. Set to

  The filling speed of the catalyst is proportional to the layer thickness T of the transport catalyst and the speed of the belt conveyor 3. The layer thickness T of the transport catalyst is set to be approximately the same as the inner diameter of the reaction tube 2, and the distance between the pair of partition walls 6 corresponding to each reaction tube 2 is also set to be approximately the same as the inner diameter of the reaction tube 2. The conveying speed of the belt conveyor 3 is set to be constant. The catalyst filling rate is usually 2 to 50 g / sec, preferably 5 to 20 g / sec.

  With the above structure, the catalyst flows down from the hoppers 1 a, 1 b... 1 x and is placed on the belt conveyor 3, and as the belt conveyor 3 is driven, the transport catalyst corresponds to each reaction tube 2 by the action of the partition wall 6. Is set to a predetermined layer thickness T by the layer thickness setting plate 7 and is supplied to the reaction tube 2 in this state.

  As a result, if the catalyst has a size that fits within the cross-sectional area of the reaction tube 2 and the input amount per unit time is equal to or less than a predetermined amount, no bridge is generated even if a large number of catalysts are input at a time. That is, as described above, the transport catalyst is set to a feed width corresponding to each reaction tube 2 by the action of the partition wall 6, and is set to a predetermined layer thickness T by the layer thickness setting plate 7. Therefore, even if a large number of catalysts are supplied to the reaction tube 2 by the belt conveyor 3 at a time, the occurrence of bridges in the reaction tube 2 can be avoided.

  As described above, if the conveyance speed of the belt conveyor 3 is constant, the amount supplied to the reaction tube 2 is not uneven, and bridges are less likely to occur. When the same amount of catalyst is supplied to each hopper 1a, 1b... 1x and the catalyst is supplied to all the reaction tubes 2 at the same conveying speed, the variation in the filling rate to each reaction tube 2 is ± 20%. It can be: As a result, the packed state of the catalyst in all the reaction tubes 2 becomes uniform, and the flow resistance (pressure loss) of the reaction fluid becomes almost uniform in all the reaction tubes 2. The plurality of hoppers 1a, 1b,... 1x provided for each catalyst transport row preferably have the same shape and the same capacity. The variation in the filling rate of each reaction tube 2 is ± 20% or less, preferably ± 15% or less, more preferably ± 5% or less, and further preferably ± 2% or less.

  In the catalyst filling machine having the above-described structure, it is particularly important to measure the amount of catalyst charged into each hopper 1a, 1b,. Specifically, it is preferable that the amount of catalyst charged into each of the hoppers 1a, 1b... 1x is measured with an accuracy within ± 5%, preferably within 1%. If the amount of catalyst input exceeds ± 5%, the variation in the filling rate increases, the variation in the filling rate exceeds ± 10%, and it becomes difficult to make the filling state into each reaction tube 2 uniform. .

The fixed bed multitubular reactor according to this embodiment is configured to supply a raw material compound by a gas phase catalytic reaction while passing a predetermined raw material compound through a number of reaction tubes 2 filled with a granular solid catalyst as described above. Oxidation gives the target compound.
The raw material compounds subjected to such a reaction include, for example, hydrogen chloride and oxygen for obtaining chlorine by a gas phase oxidation method, acrolein by a gas phase oxidation method, and propylene and oxygen for obtaining acrylic acid, gas phase oxidation Examples of the method include methacrolein, and isobutylene and oxygen for obtaining methacrylic acid.

  The reaction tube used may be coiled, but a straight straight tube is usually used. The straight pipe is usually a vertical type that is arranged in the vertical direction and allows the raw material compound to pass in the vertical direction.

As the catalyst filled in the reaction tube, for example, in the gas phase oxidation method for obtaining chlorine from hydrogen chloride and oxygen, an oxidation catalyst mainly composed of ruthenium oxide and supported on rutile titanium oxide can be cited, and further propylene and oxygen In the case of the gas phase oxidation method for obtaining acrolein and further acrylic acid from gas, and the gas phase oxidation method for obtaining methacrolein and further methacrylic acid from isobutylene and oxygen, a predetermined oxidation catalyst is used.

  The catalyst may be diluted with an inert filler that is inert to the reaction. Further, the catalyst may be divided into a plurality of catalyst layers and filled in the reaction tube. In that case, an inert filler layer may be interposed between the catalyst layers.

  Examples of the shape of the catalyst include a spherical particle shape, a cylindrical pellet shape, a ring shape, and a granular shape obtained by pulverization and classification after molding, and are not particularly limited. In general, the catalyst preferably has a diameter of 10 mm or less, and if the catalyst diameter exceeds 10 mm, the activity may decrease. In addition, when the catalyst diameter is excessively small, the pressure loss in the reaction tube increases, and therefore the catalyst diameter is usually preferably 0.1 mm or more.

  Each reaction tube filled with a catalyst used in the present invention is usually a metal tube having substantially the same shape and having an inner diameter selected from a range of about 15 to 50 mm. Here, “substantially the same shape” means that the outer diameter, wall thickness, and length of the reaction tube are within the range of the design error. The design error is usually within ± 2.5%, preferably within ± 0.5%. Although it is preferable to determine the inner diameter of the reaction tube and the catalyst diameter so that the inner diameter of the reaction tube is four times or more the catalyst diameter, it is not particularly limited.

  The reaction tube used in the present invention needs to have a smooth inner surface, and specifically needs to have a small surface roughness. Thereby, the catalyst packing density in each reaction tube can be made high. An example of such a reaction tube is a seamless seamless tube.

  The fixed bed multitubular reactor of the present invention is usually used as a heat exchange reactor. This heat exchange type reactor has a jacket (shell) part outside the reaction tube filled with the catalyst, and the reaction heat generated by the reaction is removed by the heat medium of the jacket (shell). Specifically, a disk-and-doughnut-type multitubular reactor, a non-circular baffle-type multitubular reactor, and the like are preferably used. Examples of the heat medium include a molten salt, steam, an organic compound, and a molten metal. In particular, it is preferable to use a molten salt and steam from the viewpoint of thermal stability and handleability.

  Hereinafter, the present invention will be described in detail with reference to test examples, but the present invention is not limited to the following test examples.

また、表１に示す充填速度とＢＤとの関係を図３に示した。表１および図３から、選択した充填速度９．５５ｇ／秒を標準としたとき、充填速度のばらつきが少なくとも±２０％以内であると、充填高さやＢＤのばらつきに大きな変化がないのに対して、これを外れると充填高さやＢＤの標準に対して大きくばらつくことがわかる（すなわち、充填速度が１４．３ｇ／秒（＋５０％）および４．７９ｇ／秒（−５０％）ではＢＤがそれぞれ−１％および＋１％変化している）。 [Test example]
When filling the reaction tube (nickel seamless tube, inner diameter 21 mm, length 5 m) with the catalyst, the filling height and bulk density (hereinafter referred to as BD) when the catalyst filling speed was changed were examined. The catalyst used is a columnar granular material having a diameter of 1.5 mm and a length of 3 mm, in which ruthenium oxide is supported on titanium oxide.
The catalyst filling was performed using a catalyst filling machine as shown in FIGS. 1 and 2, and the catalyst filling rate was adjusted by changing the filling time of a fixed amount (850.0 g) of catalyst. The test results are shown in Table 1.

Moreover, the relationship between the filling speed shown in Table 1 and BD is shown in FIG. From Table 1 and FIG. 3, when the selected filling rate is 9.55 g / second as a standard, if the variation in filling rate is at least ± 20%, the variation in filling height and BD does not change greatly. If it deviates from this, it can be seen that there is a large variation with respect to the standard of filling height and BD (that is, BD is different at filling speeds of 14.3 g / sec (+ 50%) and 4.79 g / sec (−50%) -1% and + 1%).

It is a schematic perspective view which shows one Embodiment of the catalyst filling machine which concerns on this invention. It is a schematic explanatory drawing which shows operation | movement of the catalyst filling machine shown in FIG. It is a graph which shows the relationship between the filling rate of a catalyst, and BD (bulk density).

Explanation of symbols

1a, 1b ... 1x: hopper, 2: reaction tube, 3: belt conveyor, 6: partition wall, 7: layer thickness setting plate, 8: chute, 9: hose, 10: filling hopper, 14: damper

Claims (4)

  When filling a large number of reaction tubes in a fixed bed multitubular reactor with a granular catalyst from above, it is necessary to fill the catalyst so that the variation in the filling rate of each reaction tube is ± 20% or less. A feature of the catalyst filling method.   A catalyst transport row is formed for each hopper under a plurality of hoppers into which the catalyst is charged, and the catalyst dropped from each hopper is transported along the catalyst transport row to the upper end opening of the reaction tube, and the catalyst is passed through the upper end opening. 2. The catalyst filling method according to claim 1, wherein the amount of catalyst charged into each hopper is measured with an accuracy within ± 5%.   A catalyst filling machine for simultaneously filling a plurality of reaction tubes with particulate catalyst from above, and corresponding to the plurality of reaction tubes, a plurality of hoppers into which a catalyst is charged are provided, and each of the hoppers is provided with a plurality of hoppers. A catalyst filling machine, wherein a catalyst transport row is formed for each hopper, and a catalyst dropped from each hopper is transported and filled above each reaction tube through each catalyst transport row. The catalyst transport row includes a conveyor that carries the catalyst flowing down from each hopper and transports it to the reaction tube, and a plurality of partition walls that are installed on the upper surface of the conveyor to partition the transport path for each reaction tube. The catalyst filling machine according to claim 3, wherein the catalyst filling machine is provided.

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