JPH0526549B2 - - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method of operating a cyclone separator to provide swirling and separating effects to a fluid stream. More particularly, the present invention relates to a method of varying the magnitude of the pressure drop across a cyclone separator without substantially limiting its separation capacity. By varying the pressure drop, the cyclone also acts as an anti-erosion vortex valve.

PRIOR ART A conventional cyclone separator is arranged to receive a tangential inflow of a gaseous or liquid fluid in which particles are suspended to form a stable, generally vertical vortex, resulting in , the separated solid or liquid particles are separated by being moved radially outward and downward over a vortex stabilizer, which at the natural change point of the vortex Or located somewhat lower. It is contemplated that such a position of the vortex stabilizer should be necessary to maintain adequate downward and outward shedding forces on the separated particles.

As far as the applicant has noticed, during the inflow and processing of particle-laden fluid in a cyclone separator, online changes can be made in the vertical length of the vortex, such that the incoming flow It has not been previously recognized that this does not involve initially terminating or changing the velocity or pressure provided. Applicants have discovered that when the length of the vortex is shortened by upward movement of the vortex stabilizer, the result is primarily an increase in the pressure drop across the cyclone. The increased pressure drop increases the backpressure in the incoming stream, while causing only a slight decrease in the efficiency with which airborne particles are separated.

Structure of the Invention The invention therefore provides that, in carrying out a coal gasification method, each of a plurality of cyclone separators has a density different from that of suspended unreacted coal and/or fly ash particles. In operating a plurality of cyclone separators connected in parallel to receive a portion of the gas stream containing particulate matter in the clean recycle gas stream from the coal gasification process, cylindrical and vertical a vortex chamber with a gas stream containing unreacted coal and/or flyash particles tangentially entering the upper part of said chamber, which has a higher density compared to the less dense gas component in the incoming gas stream; Unreacted coal and/or
or a gas flow flow means capable of forming a vortex to move the fly ash component radially outward and downward; an outlet for a gas stream not containing a dense component; and a dense outlet provided at or near the opposite end of the chamber for discharging a gas stream enriched in said dense component. a cyclone comprising: connecting an outlet of the component-enriched gas stream with at least one cyclone separator having an intermediately disposed vortex stabilizer movably disposed within the chamber at a position capable of stabilizing the vortex; A method of operating a separator, further comprising: moving said vortex stabilizer towards or away from an outlet of said gas stream at or near the top of said chamber; , at least one cyclone having externally controllable operating means for adjusting the distance between said outlet and said outlet of a gas stream not containing a dense component located at or near the top of said chamber; separator,
connected as at least one of said plurality of parallel connected cyclone separators, and an exit velocity of said fluid passing through at least one gas flow outlet opening present in each of said parallel connected cyclone separators; is substantially equal to the fluid outflow velocity of at least one of the other of the parallel connected cyclone separators. The present invention relates to a method for operating a cyclone during the performance of a coal gasification process, characterized in that at least one movable vortex stabilizing device is moved in the process.

According to the method of the invention, particles of a density different from that of the fluid (i.e. unreacted coal and/or fly ash particles) are present in said fluid (i.e. the clean recycled gas stream from the coal gasification process). The component in the flow, that is, the particulate suspended matter, can be separated from the flow containing the suspended matter in a dispersed state, and the flow can be controlled. The floating material flows into an upper portion of a generally cylindrical and vertical chamber, within which a vortex stabilizer is movably mounted, so that a vortex is formed above the vortex stabilizer;
The high-density components of most of the suspended matter are then moved radially outward and downward relative to the less dense components. Fluid without denser components flows out of the chamber through an outlet at or near the top, while fluid rich in denser components flows out of the chamber through an opening at or near the bottom. flows out through. Directing the vertical separator towards the upper outlet or the upper outlet without requiring any change in the flow of fluid into or out of the chamber other than the change brought about by moving the vortex stabilizer. By moving away from the chamber, the pressure drop across the chamber is increased or decreased and the proportion of fluid exiting through the upper and lower outlets is altered.

The present invention is applicable to the handling of virtually any suspended material that can be separated in a cyclone separator. The suspended particles can be solid, liquid, or gaseous, and the fluid in which they are suspended can be gaseous or liquid, as long as the particles are scattered within the fluid, and the fluid is different. It consists of a vine phase and has a density different from that of the particles.

The present invention has the following effects.

(1) vertical adjustment of the movable vortex stabilizer to optimize the separation performance of the cyclone separator while the separator is in flow; (2) to equalize the flow through each separator. or reduce the pressure drop through multiple cyclone separators connected in parallel via a manifold to equalize the flow through the individual separators, or to terminate or reduce the flow through the individual separators. (3) The outflow from the cyclone separator outlet can be completely closed as well to terminate fluid flow without any downstream valve; (4) movably mounted; The vortex stabilizer can be adjusted to control the amount of fluid leaving the separator, which fluid is either enriched or free of dense components;
(5) The cyclone separator of the present invention is particularly useful for controlling regeneration streams of gases or liquids, which streams are relatively rich or free of solid particles, and the solid particles are susceptible to abrasion. , and is more or less dense than the gas or liquid in which the particles are scattered.

Cyclone separators use centrifugal force in a confined high-velocity vortex to separate phases of different densities. The strength and stability of the vortex are of primary importance in determining the separation capacity and erosion resistance of the cyclone. Since it is extremely important to improve the reliability, separation efficiency, and corrosion resistance of cyclones, various studies have been conducted to develop cyclones that are less erosive and have better performance. In particular, research has been carried out inside the cyclone, which includes a vortex stabilizing device.

The term "stabilized" is used for devices that keep the vortex in the center of the cyclone and reduce the dissipation of turbulent energy.

A number of cyclone flow, velocity, acoustic, and pressure drop experiments were performed under normal ambient conditions. Most of these experiments
carried out with a 0.5 m tangential inlet cyclone, which passes through the second stage.
FCC commercial cyclone (second age FCC
This is a Plexiglas (registered trademark) model with a scale of 0.31 times that of a commercial cyclone. The scale of the model is chosen by aiming at the Reynolds and Strouhal numbers of a real fluid cracking catalyst (FCC) cyclone at the same inlet velocity (25 m/sec). The model is tested with and without vortex stabilizers of various configurations. The wall roughness is matched by 10 mesh and a 0.11 cm "thick" wire screen is closely fitted to the inner wall of the cyclone. This model is typical of the cyclones used in modern catalytic cracking units, except that it is a particularly high performance design. Distinguishing features of such designs are large inlet-to-outlet area ratio, narrow inlet, and long cyclone body.

A number of variations of the basic cyclone are tested to determine the effects of hopper geometry, ballast geometry, and wall roughness on vortex action within the cyclone.

All experiments used air as the primary flow (to simulate gaseous hydrocarbons). Air is supplied by three 300 kW blowers, which have a typical overall capacity of 1 m ³ /sec.
Most experiments were conducted at approximately 0.6 m ³ /sec at 117 kPa.
It was held in This flow rate corresponds to an inlet velocity of 17 m/sec. At this flow rate, the Reynolds number based on the outlet tube diameter (Re _z =〓 _g W _i 〓 _i /〓) is approximately 2.8×10 ⁵ . At such high Reynolds numbers, the velocity profile is essentially independent of flow rate, so the actual flow rate is allowed to vary somewhat, but all measurements are 110 −130kPa,
Obtained at a temperature of 16-29°C and a flow rate of 0.5 m ³ /sec or higher. For comparison, all velocity profiles were adjusted to an inlet velocity of 17 m/sec.

Cyclones are characterized by large radial pressure gradients that are balanced by centrifugal forces in the swirling flow. Therefore,
There is a relative vacuum at the center, or core, of the vortex. This low pressure core will likely "suction" any nearby surface, thus stabilizing the vortex appendage to that surface.

A vortex stabilizer device was placed within the model cyclone to suppress erratic operation of the vortex.

Vertical pins or vortex finders may be added to the ballast to limit and center the lateral precession of the vortices. The ballast pin with a diameter of 0.6cm is
It was found to be insufficient to limit vortex precession in the test cyclones. If a larger pin is used to center the vortex,
Vortex stabilizers are more effective. A 1.9 cm diameter rod was tested with better results.

Several types of vortex stabilizer devices have been tested with varying results. For the most part, flat plates or circular disks have been found to be satisfactory. The diameter of the vortex stabilizer device must be approximately the diameter of at least one vortex exit tube.
The maximum diameter of the ballast in commercial models is primarily set by weight limitations and must be large enough to allow catalyst to flow downwards while stripping gas upwards simultaneously passes through. It is limited only by providing a large annulus between the periphery of the ballast and the vessel wall.

The vortex finder is not critical to cyclone performance, and rather than being provided in a vortex stabilizer device, the vortex stabilizer is placed at a short distance from the vortex outlet, i.e. at least about 2-3 times the vortex outlet tube diameter.
It is located in However, if the vortex finder is located at a larger distance, e.g. 5-8 times the vortex exit tube diameter, then
Preferably, the vortex stabilizer device includes a vortex finder. Preferably, such vortex finder is about 1/3 or more of the vortex length.

Based on aerodynamics, vortex stabilization is desirable for increasing separation efficiency while minimizing both pressure drop and erosion. The vortex stabilizer reduces the pressure drop across the model cyclone by 10− even though the peak vortex velocity is greatly increased.
Reduced by 15%. This effect is exceptional in cyclones since increasing swirl velocity usually mostly increases pressure drop. Vortex stabilizers appear to reduce turbulent energy dissipation in the cyclone as the pressure drop decreases.

The test loop is made of PLEXIGLAS (registered trademark) as shown in FIG. The catalyst enters the bottom of an 8 cm x 4.3 m riser 10 and is transported by air entering through a concentric 0.04 m nozzle 11.

The differential pressure (〓P) 12 across the riser has not been precisely measured, but is on the order of 0.25 KPa. An air flow rate of 1.8-2.9 Nm ³ was used in the riser 10. These flow rates are
This corresponds to a surface velocity of 7.2 to 11.5 m/sec in the riser. The air flow rate measurement is via a rotameter. The catalyst flow rate in the riser was varied from 2 Kg/min to 9 Kg/min. The solid flow rate is controlled by the catalyst holding tank 15 and the riser pipe 1.
Stamndpipe with a diameter of 0.076m between
This was done by setting a pinch clamp 13 at 14. The catalyst flow rate was determined by stripper cyclone 17
Pinch clamp 1 between the and catalyst holding tank 15
6 and measuring the rate at which the level increases within the stripper cyclone body. For this measurement, air was directed into the stripper cyclone 17 and a catalyst density of 0.8 g/cm ³ was assumed.

At the top of the riser 10, a right angle turning section 1
8 and a transition section 19, the transition section is
A rectangular cyclone inlet (58 x 10 ^-4 m ² ) with a rectangular shape of 0.152 m high x 0.04 m wide from a 0.076 m pipe.
It is connected to 31. The gas velocity at the cyclone inlet changes from 5.2 to 8.4 m/sec.

Gas comes from stripper cyclone 17
Exit via 0.076m pipe 20. A second cyclone 21 collects catalyst from the top of the stripper cyclone. Paper filter 22 allows clean gas to pass to the atmosphere and captures catalyst that escapes from the second cyclone.

The catalyst leaves the stripper cyclone 17 via a standpipe 23. The pinch clamp 16 is
Used to control the catalyst level at the bottom of the stripper cyclone 17. The catalyst holding tank 15 at the bottom of the stripper cyclone 17 also provides a storage which supplies the riser via the 0.076 m standpipe 14.

A detailed illustrated elevational view of stripper cyclone 17 is shown in FIG. The cyclone section 24 is fabricated from pipe with an internal diameter (ID) of 0.142 m and includes a vortex finder 25 and a vortex stabilizer 26 located at a selected distance from the bottom of the clean gas outlet pipe 20. ing. stripping area
zone) 27 was similarly manufactured from a pipe with an internal diameter of 0.142 m. The clean gas outlet 20 is a 0.076 m inside diameter pipe with a wall thickness of 0.3 cm thick and extends 7 inches through a swirl-inducing zone 30 toward the top of the cyclone zone 24. . The outlet 23 of the catalyst or separated components is the inner diameter
It is a 0.076m pipe. The gas containing particles is
It enters the vortex induction area 30 via a tangential inlet 31 .

The vortex stabilizer 26 is 10.2 cm in diameter (for most tests), 1.2 cm thick at the edges and 2.5 cm thick in the center. Vortex finder 25 is 6.4 cm long and has a diameter at the base.
1.27 cm and 0.635 cm in diameter at the top.

In the embodiment shown, the vortex stabilizer 26 is provided with a skirt tube 35 surrounding a guide tube 36 . A seal ring 37 is provided to prevent fluid flow between tubes 35 and 36. Vortex stabilizer 26
is vertically movable by means of a rack and pinion drive gearing 38. The drive gear shaft is supported by a bearing 39, and a seal ring 37
and a handle or drive device 40
is provided, the drive being operable from a position outside the cyclone separator.

Example Gaseous suspension of solid particles
In tests where they are conducted in an apparatus of the type shown, the pressure drop across the cyclone separator at the location of the vortex and the outlet of the upper, particle-free fluid. The dependence of the pressure on the pressure drop was clearly demonstrated. In the tests, the cyclone separator had a vortex area of 51 cm in diameter, and the vortex length varied between 91 cm and 43 cm.
Suspension of particles was introduced at an inlet pressure of 117 pa gauge. For a vortex length of 91 cm, the pressure drop from the inlet aperture to the outlet aperture for particle-free fluid is
21 Pa, and the pressure drop from the inlet to the outlet of the particle-rich fluid is 12 Pa. For a vortex length of 43 cm, the pressure drop from the inlet to the outlet of the particle-free fluid increased to 72 Pa, although the pressure drop to the outlet of the particle-rich fluid was still more than 12 Pa. In those tests, the flow split was varied by a factor of approximately 2, even though the underflow of particle-rich fluid was not contained inside the cyclone separator. .

In cases where a stream of particle-rich fluid is contained within a cyclone separator such that there is no fluid outflow, the movement of the vortex stabilizer towards the outlet of the particle-free fluid will reduce the pressure across the cyclone separator. The descent can be increased to the point where the flow is terminated. In such operation, the cyclone separator is acting as a valve. The invention is particularly advantageous when the incoming fluid contains suspended solid particles that tend to erode the valve seat. Tests in systems of the type illustrated show that there is little, if any, wear on the vortex stabilizer in the cyclone separator just when the vortex stabilizer smoothly closes the outlet of the particle-free fluid. showed that. This means that particles that can cause wear are continuously ejected radially outwards by cyclonic action, so that along the surface of the vortex stabilizer or the edge adjacent to the outlet of the particle-free fluid. This is based on the fact that the only fluid that flows is substantially free of such particles.

In coal gasification processes, the produced gas containing suspended particles of unreacted coal and/or fly ash is desirably cooled by diluting the produced gas with a flow of clean regeneration gas. The present cyclone separator is particularly well suited for use as an erosion resistant valve to control such operations. Most valves tend to be severely attacked by floating solids at the elevated pressures and temperatures commonly used for coal gasification. For the present cyclone separator, the reaction products containing solids can be flowed tangentially and the mixing solids circulate around the outside as they do in a common cyclone. However, for the present system, the flow of relatively clean regeneration gas through the upper outlet can be controlled by simply moving the vortex stabilizer vertically, and the vortex valve
resulting in a cyclone separator that acts as a
This results in the mixed solids being carried downwards and outwards in the particle-rich gas stream.

In cases where large amounts of solid particles suspended in large amounts of gas are to be separated, as is common in catalytic cracking and various other manufacturing processes,
Multiple cyclone separators are often operated in parallel, each separator connected to receive a portion of the solids-laden stream from the manifold, and the separated solids discharged into a common hopper. . For example, it is common for eight cyclone separators to be manifolded together to receive catalyst-laden flue gas from a regenerator. In such an operation, it is difficult to feed all the cyclones equally, and the solids collected from some of the cyclones may flow through the hopper and through the other cyclones. There is a tendency to return to the flowing flue gas. However, when using the present cyclone separator, the vortex stabilizer can be adjusted without interrupting operation to control flow diversion between multiple separators operating in parallel.

In general, the present invention is useful for separating solid, liquid or gaseous particles that are scattered in a gaseous or liquid fluid having a different density than the particles. The method can be used to control flow between a lower and upper flow of either a particle-free fluid or a particle-rich fluid. Particularly in situations where the underflow is contained within the vortex chamber of the separator, the present invention eliminates any substantial erosion caused by altering the pressure drop through the cyclone separator or by attrition. By terminating the flow in a manner that also prevents wear, it can be used as a bubble means to control the flow of fluid containing particles that cause wear.

[Brief explanation of drawings]

FIG. 1 is a schematic elevational view of a test loop used to test the apparatus used in the invention; FIG. 2 is a schematic elevational view of a cyclone separator used in the invention.
1 is a schematic elevational view of two embodiments; FIG. 10... riser pipe, 13, 16... pinch clamp, 14, 23... riser pipe, 15... catalyst holding tank, 17, 21... cyclone, 20...
Outlet pipe, 23...Catalyst outlet, 25...Vortex finder, 26...Vortex stabilizer.

Claims (1)

[Claims] 1. In carrying out the coal gasification method, each of the plurality of cyclone separators separates coal having a density different from that of suspended unreacted coal and/or fly ash particles. A cylindrical and vertical vortex is used to operate a plurality of cyclone separators connected in parallel to receive a portion of the gas stream containing the suspended particles in the clean recycle gas stream from the gasification process. a chamber; and when a gas stream containing unreacted coal and/or flyash particles is allowed to flow tangentially into the upper part of said chamber, unreacted particles of greater density compared to the less dense gas components in the incoming gas stream gas flow flow means capable of forming vortices to displace coal and/or flyash components radially outward and downward; an outlet for a gas stream not containing a dense component provided in the vicinity thereof; and an outlet provided at or near the opposite end of the chamber for discharging the gas stream enriched in said dense component. connecting an outlet of the dense component-enriched gas stream to at least one cyclone separator having an intermediate vortex stabilizer movably positioned in the chamber at a position capable of stabilizing the vortex; A method of operating a cyclone separator, further comprising: moving said vortex stabilizer towards or away from an outlet of said gas stream at or near the top of said chamber; at least one externally controllable operating means for adjusting the distance between the device and the outlet of the gas stream, which does not contain a dense component, and is arranged at or near the top of the chamber; one cyclone separator connected as at least one of said plurality of parallel connected cyclone separators, at least one gas flow outlet opening present in each of said parallel connected cyclone separators; said parallel connected cyclone separators in a position such that said fluid exit velocity therethrough is substantially equal to said fluid exit velocity of at least one of the other of said parallel connected cyclone separators; At least 1 inside at least one of the vessels
A method of operating a cyclone in carrying out a coal gasification process, characterized in that two movable vortex stabilizers are moved.