JP2014205145A - Apparatus and method for top removal of granular and fine material from fluidized bed deposition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus and a method for top removal of granular material from a fluidized bed deposition reactor, which enables a decreased disengaging height and provides passive means of controlling the bed level despite deposition increasing the weight and height of the bed.SOLUTION: The savings from reducing the disengaging height allow use of a taller fluidized bed 222 in a shorter overall reactor length 244 and thus provides increased production with reduced reactor cost. The separation of a gas inlet 212 from a product outlet 231 allows the gas inlet area to be cooler than the product outlet. The separation of the product grinding, caused by the inlet gas, from the outlet reduces the loss of seed in the product and produces a more uniform product. Removing the hot product and the hot gas at the same place 230 allows energy recovery from both in a single step.

Description

The present invention relates generally to the field of precipitation reactors, and more specifically to an apparatus and method for upward removal of particulate matter from a fluidized bed precipitation reactor.

(Cross-reference of related applications)
Not applicable (Federal-sponsored statement on research or development)
Not applicable (Appendix description)
N / A Fluidized bed reactors have a long tradition in the chemical industry, where fluidized beds usually consist of finely divided and expensive catalyst, so the reactor is designed to prevent catalyst loss. There is a need. Therefore, a practice has been developed that requires a large separation height above the floor and uses a cyclone to capture the fine powder and return it to the floor. A concept called total separation height, or TDH, has been developed that estimates the height at which particles that should settle due to gravity have settled. An internal cyclone was provided at this height to capture finer powder and return it to the floor. The catalyst was removed from the bottom by gravity whenever it was removed. In addition, reactors called dilute phase or transport reactors are entrained with all solids and carried through the reactors to exit from above, and these reactors are recognized as beds. There was nothing to be done. When these gas-solid reactor concepts are applied to the design of a precipitation reactor into which gas is introduced so that bed particles grow, the dilute phase reactor mainly produces undesirable fine powders. There was a big problem. Thus, the majority of precipitation reactors are fluidized beds,
Therefore, a fluid bed basic design with a large separation height and a bottom solids outlet has been used. The idea of an internal cyclone was rarely used due to the deposition on the outside of the cyclone and the challenge of reintroducing the particles without blocking the cyclone exit. Since some degree of fine powder is always formed, most precipitation reactors are equipped with an external cyclone or filter to confine the powder and prevent damage to the equipment used for exhaust recovery. Yes. In this way, the historical approach allows the product to be removed from the bottom, provides a large separation height to minimize product loss, and uses an external powder take-off, It was that. The main use of the deposition reactor is in high-purity silicon deposition.
US Pat. No. 6,451,277 to B describes a floor heating method in which beads are removed from near the top surface of the floor and then heated back to the floor. Note that product 3 is still removed from the bottom. In the above patent, this floor heating method was rejected if it supported the preferred option of removing the beads from the bottom by gravity and reheating them back to the floor in a pulsed fashion. Lord, in US Pat. No. 6,827,786, describes a multi-stage deposition reactor that uses a large bed height to increase the production of silicon by adding gas injection points along the sides of the reactor. Explains in detail. This design expands seed generation by comminution along the reactor due to extra nozzles, with some precipitation occurring far from the inlet, but most of the comminution and precipitation is at the bottom where the solid product is removed. To happen. Lord
As shown in the third column, line 25 of the “De Beers” article, a certain residence time and temperature are required to ensure complete product crystallization and bead dehydrogenation. Discussing something. He does this with a short residence time in a hot pulsed bead heater. Many of Lord and his literature do not discuss energy recovery from exhaust,
Load discusses in US Pat. Nos. 5,798,137 and 6,451,277 that heat from the effluent product is used to heat the incoming air.

The main disadvantages of the prior art are the persistence of the inherited fluid bed design of providing a bottom outlet and a large separation space, and the introduction of a low temperature precipitation gas that can cause a large amount of seed formation by comminution. Is accepting the adjoining requirement to do the same product where the hot product is removed. Lord attempts in various patents to address the problem of heat and seed generation by dispersing gas injection, but enough gas at the bottom to fully fluidize the bed. There is a limit to what can be achieved in this manner since it must be injected. Inevitably, the bottom temperature is 800 to provide the necessary crystallization.
It must be maintained above 0 ° C., so that some species are not of the product and this time the product is contaminated by the “seed beads” that have been destroyed. When the high temperature and the high concentration of the precipitated gas are combined, as a result, the reaction rate increases, the wall deposits increase, and the risk of aggregation and clogging increases.

This multi-stage method approach further leads to tall reactors, and the production of high purity liners for such reactors has cost and manufacturability issues, which limits the number of stages,
This in turn limits the production capacity of a given diameter reactor.

If the floor level is measured and the floor is growing, the correct action is taken to remove part of the floor by opening the valve and changing the purge flow to allow the appropriate amount of beads to leave the floor. It is also necessary to be able to. A malfunction or valve clogging causes a situation where the floor becomes too high or too low. Both of these conditions are undesirable turbulent conditions.

US Pat. No. 6,451,277 US Pat. No. 6,827,786 US Pat. No. 5,798,137

"De Beers" paper, column 3, line 25

The main object of the present invention is to provide a low-profile reactor that is more productive.
Another object of the present invention is to provide a passive method of level control.
Another object of the present invention is to provide a product of better quality.

Another object of the present invention is to reduce the need for high temperatures at the bottom of the reactor.
Yet another object of the present invention is to reduce the risk of clogging.
Yet another object of the present invention is to reduce the thickness of wall deposits.

Another object of the present invention is to reduce the pressure in the product removal system.
Another object of the present invention is to recover energy.

Other objects and advantages of the present invention will become apparent from the following description, taken in conjunction with the accompanying drawings, wherein certain embodiments of the invention are disclosed by way of illustration and example.
In accordance with a preferred embodiment of the present invention, an apparatus and method for upward removal of particulate matter from a fluidized bed deposition reactor, wherein the product is withdrawn from the top of the reactor and the particulate product is evacuated. An apparatus and method is disclosed that includes separation from the product, simultaneous heat recovery from the product and gas, and optional additional powder and heat recovery.

The technical advantages of this design are passive level control, reduced separation height, reduced reactor height and increased fluidized bed height, separation of the gas inlet from the product outlet, production Detachment of product comminution from the product outlet, energy recovery and resulting reduction in capital and operating costs, product quality improvement, and increased throughput at a given reactor diameter.

The drawings form part of the present specification and include exemplary embodiments of the present invention that may be embodied in various forms. It should be understood that various aspects of the present invention may be shown as being oversized or enlarged to facilitate understanding of the invention.

FIG. 2 is a block diagram illustrating the operation of a prior art fluidized bed deposition reactor having a bottom extraction section and a large separation space. FIG. 6 is a similar view with modifications to show the advantages of the present invention. It is detailed explanatory drawing of the upper part of a reactor, and has shown the mechanism of granular particle taking-out. It is a block diagram of the product separator provided with the integrated heat recovery part.

A preferred embodiment will now be described in detail. However, it should be understood that the present invention can be embodied in various forms. Accordingly, the specific details disclosed herein are not intended to be limiting, but may be practiced in any suitable detailed system, structure, or manner for claim basis and for those skilled in the art. It should be construed to be a representative standard for teaching use.

Referring first to FIG. 1, a block diagram of a typical fluidized bed deposition reactor is shown, which comprises a containment vessel or liner 111 at a height 144, a gas introduction means 112, an optional gas. Delivery means 113, bottom product removal means 114, floor heating means 115, gas / powder mixture outlet 116,
Connection means 127, powder / gas separation means 117, powder take-out means 118, and gas outlet 119
It has. The containment vessel 111 surrounds a bed 120 of granules that has been fluidized by bubbles 121 and has an average upper surface level 122, above which the product granules 123 that have sprung up from the floor are contained. In the reduced separation space 124, it is pushed up by a random collision in the floor, and it is arced while falling due to gravity, while the entrained minute powder particles 125 continue to rise and exhaust 126 with gas / powder mixture outlet 116
Exiting the connecting means 127 and entering the powder / gas separating means 117, where the powder 125
Most of the gas is extracted from the gas 126 and then finally exits the system via the powder extraction means 118, while the gas 126 and the remaining powder exit through the outlet 119. Differential pressure gauge 12
8 measures the pressure difference between the bottom product removal means 114 and the gas outlet 119. This measurement represents the level 122 of the granular floor 120. The bottom extraction means 114 is used to control the top level 122 so that the separation space 124 is maintained so that the product granules 123 are returned to the granule floor 120 and can be removed by the bottom product extraction means 114. Has been.
This is a very rough block diagram and the patent literature is packed with various methods and machines that have been proposed to meet these requirements. Two or more gas inlets may be provided and the gas delivery mechanism may be omitted, and a wide variety of heating means may be used, and powder removal may be performed using the illustrated cyclone, filter, or another gas purifier. It can also be performed by a device.

FIG. 2a in accordance with the present invention shows a block diagram similar to FIG. 1, but with a gas / granular separator means in which the particulate product is sandwiched before the exhaust enters the gas / powder separation means 217. Modifications have been made for removal from the top via 230. Another modification is that the differential pressure transmitter 128 shown in FIG. 1 has been removed because it is no longer needed for floor level control. Therefore,
The present invention includes a containment vessel or liner 211 at a height 244, gas introduction means 212, optional gas delivery means 213, optional bottom product removal means 214, floor heating means 215, gas / powder / grains. Body mixture outlet 216, first connection means 241, gas / particle separator means 230 with granule removal means 231, optional heat recovery means 242, another connection means 229, gas / powder separation means 217, another Optional heat recovery means 243, powder extraction means 218, and gas outlet 219 are provided. The containment vessel 211 encloses a granular bed 220 fluidized by bubbles 221 and slag 240 and having an average upper surface level 222 above which it was sprung above the floor. Some of the particles 223 are pushed up by a random collision in the floor within the reduced separation space 224 and are falling in an arc while falling by gravity.
On the other hand, some of the particles 236 and the finely entrained powder particles 225 continue to rise, and the exhaust 23
3 exits the gas / powder / granule mixture outlet 216 and enters the gas / granule separator means 230 through the connecting means 241 where the granules are removed via the granule take-out means 231.
The remaining gas and powder exit through the gas / powder top outlet tube 229 and then enter the gas / powder separation means 217, where most of the powder 225 is removed from the gas 233 and finally In particular, it leaves the system via the powder extraction means 218, while the gas 233 and the remaining powder exit through the outlet 219.

In order to achieve large particle removal, the average top surface level 222 is very close to the gas / powder / particle mixture outlet 216 so that the product particles 23 that have sprung above the floor.
A portion of 6 is pushed up in the separation space 224 and does not draw an arc while falling due to gravity, but continues to rise with the entrained powder 225 and exits to the gas / powder / particle mixture outlet 216. come. Because the average floor level 222 is proximate to the outlet 216, the floor level 222 can be higher and / or more full height 244 compared to the prior art shown in FIG. it can.

FIG. 2 b shows in detail the various mechanisms that allow the product granules 236 to be carried out to the gas outlet 216. The basic mechanism is the random protrusion of product granules 236 from the upper surface 222 of the floor and the airing of these granules to the gas / powder / particle mixture outlet 216. Furthermore, the floor level oscillates up and down due to the formation of the gas slug 240, which causes certain sections of the floor to be lifted to a high level 232, and eventually the floor level falls to the low level 234 when those sections are flipped. . Level 2 is excessively high enough to be temporarily above the exit
35 can be reached. The outlet tube 241 can be attached to the outlet 216 at 90 ° as shown or sloped above or below the horizontal direction. The selected angle is the outlet pipe 24
It can be obtained by applying a standard air transport calculation method using a gas velocity within 1.

FIG. 3 shows a more detailed block diagram of a product separator 330 with an integrated heat recovery system 301 suitable for high temperature, high purity applications. As the gas / powder / granular mixture 333 enters the product separator 330 through the inlet 357 through the heat recovery system 301 via the penetration 358, the gas and powder 356 separate and rise to the top. , Exiting through the outlet tube 329, while the granules 336 are separated and descend to the bottom outlet 331 where they are fluidized by the purge stream 359 and withdrawn as needed.

The heat recovery system 301 is configured with a heat transfer fluid 360 in a container 351 that is shaped to capture heat 350 from the product separator wall and is an inlet for the heat transfer fluid 360. 354 and outlet 355. The container can utilize a variety of heat transfer fluids, such as water or hot oil. Usually, the vessel is conveniently a pressure vessel that allows heat recovery at higher temperatures. Heat may be transferred from the wall to the container by radiation, conduction, or convection, using well-known heat transfer techniques, so that heat transfer from gases and solids to the wall is enhanced. Also good. Similarly, well-known gas-solid removal techniques such as cyclones or filters may be used to enhance gas-solid separation.

In a particularly advantageous design, heat is transferred by radiation from the hot surface of the product separator to the pressurized vessel, where water 352 flows in via inlet 354 and steam 353 exits 355.
It is supposed to flow out through.

One example using FIG. 2 is as follows. The vessel diameter is 300 mm, the liner total height 244 is 7 meters, the average floor level 222 is 6 meters, the high level is about 6.6 meters, and the low level is about 5.4 meters. The gas superficial velocity at the top of the vessel is 4.7 ft
/ S (1.4 m / s). The average particle size of the granules is 1 mm and the final velocity is 21.8 f.
t / s (6.56 m / s). The final velocity of the particles is about 4 times the superficial gas velocity. This means that in order to carry the granules out of the reactor, the local velocity in the area directly above the floor must have a local surge 4 times higher than average. A velocity surge of this magnitude occurs approximately 20 cm above the floor near the top surface of the floor. The slag 240 has a maximum length of about 1.2 meters, so the periodic growth and burst of slag results in a height change of 1.2 meters between the low and high levels. The slag further accelerates the granular particles as they burst, and the particles are consequently entrained and exit the reactor. Therefore, the particle take-out changes due to the pulsation of the slag 240.

Comparing under similar operating conditions with an average floor level 122 in FIG. 1 of 6 meters, the total height should be 10 meters to ensure the separation space normally required under the prior art.

The granules and gas at the bottom of the reactor are at 700 ° C and are heated to a stream 23 at a temperature of 800 ° C.
3 exits the reactor through outlet 216. They enter the cyclonic product separator 230 through a tangential inlet, and gas and solids are swept into the vessel wall, improving gas-to-wall heat transfer. The cyclone has a diameter of 10 inches (250 mm) and a length of 6
ft (1.8 m). This is longer than that required for solid removal only to provide sufficient surface area for heat transfer. Both gas and particles are 600 ° C
Go out. The powder / gas separator 217 is similar in size, but can only take about half the heat due to the reduced temperature difference. The gas and powder then exit the powder / gas separator at 500 ° C. Both heat recovery systems are a practical standard useful in facilities for a variety of purposes and therefore always recover heat as 150 psgi steam that is in demand.

Although the invention has been described in connection with certain preferred embodiments, it is not intended to limit the scope of the invention to the particular forms described, but is instead defined by the claims. It is intended to cover alternatives, modifications, and equivalents that may be included within the spirit and scope of the invention as described.

111, 211 Containment vessel or liner 112, 212 Gas introduction means 113, 213 Gas delivery means 114, 214 Bottom product extraction means 115, 215 Floor heating means 116 Gas / powder mixture outlet 117, 217 Powder / gas separation means 118 218 Powder extraction means 119, 219 Gas outlet 120, 220 Granule floor 121, 221 Air bubbles 122, 222 Average upper surface level 123, 223, 236, 336 Granule 124, 224 Separation space 125, 225 Powder 126 Exhaust 127, 229, 241 Connection means 128 Differential pressure gauge, Differential pressure transmitter 140, 240 Slag 144, 244 Liner height 216 Gas / powder / particle mixture outlet 230 Gas / particle separator means 231 Particle take-out means 232 High floor level 233 Exhaust, gas 235 Excessively high floor level 242, 243 Heat recovery means 301 Integrated heat recovery system 329 Outlet tube 330 Product separator 333 Gas / powder / particle mixture 350 Heat from product separator wall 351 Container 352 Water 354 Thermoelectric fluid inlet 355 Heat transfer fluid outlet 356 Gas and powder 357 Entrance to heat recovery system 358 Penetration 359 Purge flow 360 Heat transfer fluid

Although the invention has been described in connection with certain preferred embodiments, it is not intended to limit the scope of the invention to the particular forms described, but is instead defined by the claims. It is intended to cover alternatives, modifications, and equivalents that may be included within the spirit and scope of the invention as described.
(Item 1)
In an apparatus and method of operation for upward removal of particulate matter from a fluidized bed precipitation reactor,
A container of a set height having at least one gas inlet at or near the bottom and at least one gas and solid outlet at or near the top;
A bed of variable-sized granular particles where fluidization and precipitation occurs by gas flow;
A gas / particulate product separator means;
An actuating method, wherein the height of the bed of granular particles can be increased until a stable height is reached.
(Item 2)
An apparatus for recovering heat while separating a particulate product, the instrument comprising one or more product separator means and one or more heat recovery means.
(Item 3)
The instrument of claim 1, further comprising at least one means for removing the particulate product at the bottom.
(Item 4)
The instrument of item 2, wherein at least one of the heat recovery means is primarily due to radiation to a heat recovery boiler.
(Item 5)
Item 3. The instrument of item 2, wherein two or more separator means are used to provide two or more product streams having different average particle sizes.

Claims (5)

In an apparatus and method of operation for upward removal of particulate matter from a fluidized bed precipitation reactor,
A container of a set height having at least one gas inlet at or near the bottom and at least one gas and solid outlet at or near the top;
A bed of variable-sized granular particles where fluidization and precipitation occurs by gas flow;
A gas / particulate product separator means;
An actuating method, wherein the height of the bed of granular particles can be increased until a stable height is reached. An apparatus for recovering heat while separating a particulate product, the instrument comprising one or more product separator means and one or more heat recovery means. The instrument of claim 1, further comprising at least one means for removing particulate product at the bottom. The instrument of claim 2, wherein at least one of said heat recovery means is primarily due to radiation to a heat recovery boiler. 3. An instrument according to claim 2, wherein two or more separator means are used to provide two or more product streams having different average particle sizes.

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