JPS6146167B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The concept of separating air-entrained solids from a mass of solid particulate material by passing the gas through the same is not new. This philosophy is based on the “Chemical Engineer’s Handbook,” edited by Perry, 4th edition, and McGraw-Hill (McGraw-Hill.
Graw-Hill), pages 20 to 74. Special applications of the same concept are described in numerous patents. U.S. Patent No. 890625 to TA Edison
No. 2493356 of Mescier et al.
No. 3220165 of Mr. Howie, No. 3594991 of Mr. Berz, No. 1995293 of Mr. Clark and French Patent No.
No. 899,920 each describe methods and apparatus structures for applying the same principles.

The methods and apparatus described above to put the above principles into practice do not require complicated designs or problems with clogging or pressure drop caused by airborne entrained solids contained in the feed gas accumulating within the apparatus. It is characterized by a low operating coefficient, which is largely attributed to its inability to resolve.

The present invention provides a significantly simpler process flow and apparatus which allows continuous operation over long periods of time in which even submicron-sized suspended entrained solids contained in the feed gas are separated very effectively. provides the structure of

The method and apparatus of the invention will now be described with reference to the accompanying drawings.

Referring to FIG. 1 of the accompanying drawings, a cylindrical container 1, usually having a flat or frustoconical top and a tapered frustoconical bottom, has a gas inlet 2 located at the top of the container. It has a solids outlet 4 at the bottom and at least one solids inlet 5 laterally arranged at the top of the vessel. A cylindrical wall member 6 having a louvered surface and a diameter smaller than the diameter of the container 1 is arranged concentrically within the container 1 to create an annular space 7 between the side wall of the container 1 and the wall member 6.
is left behind. A cylindrical wall member 6 is sealed at its upper end to the top of the container 1 for closing an annular space 7 at the top of the space. A rigid member 8 is attached to the top of the wall member 6 and to the frustoconical top of the container and closes the top of the annular space 7 against the inflow of particulate solid material 14. The annular space 7 is open at the bottom and communicates with the frusto-conical bottom of the container 1 . a diameter smaller than the diameter of the first cylindrical wall member 6;
and a second cylindrical wall member 9 having a louvered surface is arranged concentrically within the first cylindrical wall member 6 to form an annular space extending between the two cylindrical wall members from top to bottom of the container 1. is left behind. A second cylindrical wall member 9 communicates with the gas outlet 3 at the top of the container 1 and projects generally beyond the top of the container 1 as a chimney through which the treated gas leaves the container. The lower end of the cylindrical wall member 9 engages a downwardly tapered conical shroud 15. The conical enclosure 15 is provided with a slot 16 at the bottom which is laterally closed by shield rings 17. slot 16
communicates the interior of the cylindrical wall member 9 with the frusto-conical bottom of the container 1. A mass of granular contacting solid material 14 fills the annular space between both cylindrical wall members 6 and 9, the second
the top of the container 1 surrounding the upper end of the cylindrical wall member 9 and the frusto-conical bottom of the container 1;
The particulate solid material is therefore in open communication with the solids outlet 4. A first solids transport device 11 connects the solids outlet 4 of the container 1 with the lower end of the external elevator 10. The solids handling device 11 can be any conventional solids handling device such as a mechanical vibrating conveyor, screw conveyor or belt conveyor. The speed at which the conveying device 11 is actuated can be varied, so that when it is actuated it controls the speed at which the contacting solid material moves downward in the annular space between the two wall members 6 and 9. elevator 10
may be any conventional solids conveyor suitable for conveying solids vertically. Conventional bucket elevators become simple and reliable vertical conveying equipment. A second solids transport device 12 is provided to convey particulate solid material from the top of the elevator 10 to the solids inlet 5 at the top of the vessel 1. A solids separator 13 capable of separating pulverized solids from granular contacting material is provided on one or the other of the solids conveying devices 1
1 or 12 is inserted into the flow passage.
A suitable solids separator has eyes sized to permit the passage of very finely ground material that has been treated and separated from the gas by the granular contact solid material being circulated through the device. Included are vibrating mesh separators, which can have either reciprocating or rotating meshes. If the finely divided solids removed from the feed gas are oily or sticky, they may be incinerated or dissolved to remove the contact solid materials instead of being mechanically separated by sieving. It does not matter if it is removed from
The third cylindrical wall member 18 is larger than the diameter of the cylindrical wall member 9.
50.8 to 152.4 mm (2 to 6 inches)
It is a porous cylindrical wall with a large diameter. The pores are sized to allow passage of essentially all particulate contact material. If the third cylindrical wall member has large contacting solid material particles, for example,
A lateral flow of finely divided contacting material particles, e.g. 6 to 8 meshes, through the louvered holes in the cylindrical wall member 9, although it is not essential if the particles are 3.175 to 6.35 millimeters (1/8 to 1/4 inch) in size. used to control. The function of the cylindrical wall member 18 will be explained in more detail with reference to FIG.

FIG. 2 is a cross-sectional view of container 1 taken along line 2--2. The ribs 20 are strong members that hold the first cylindrical wall member 6 in place. The ribs 20 are slotted along their respective lengths to allow free flow of feed gas through the annular space 7. The gas distributor 19 is a V-shaped member inserted into the gas inlet 2 to direct the incoming gas from the inlet 2 into the annular space 7 in both directions. In addition to directing the feed gas in both directions from the inlet 2, the distributor 19 also has the effect that the feed gas is in direct vertical contact with the louver-shaped wall member 6, blocking or partially blocking the louver holes at the point of direct vertical contact. Prevent such direct vertical contact that could result.

FIG. 3 of the accompanying drawings shows the internal structure, in particular the conical enclosure 15 and the slot 16 at the lower end of the cylindrical wall member 9.
and FIG. 2 is an elevational view of the container 1 with a portion cut away to show details of the outer shield ring 17.

FIG. 3 shows a particularly desirable and effective construction of the conical bottom of the container 1. The bottom is formed by two frusto-conical members 27 and 28. The upper frusto-conical member 27 has relatively steeply sloped side walls such that its elements form an angle of 65 degrees to 90 degrees with the horizontal, while the frusto-cone member 28 has relatively steeply sloped side walls. With non-steep side walls, the elements of the member form an angle of 45 degrees to 70 degrees with the horizontal. These 2
This arrangement of frusto-conical members includes both cylindrical wall members 6
and 9 to allow a smooth uninterrupted flow of the particulate contacting solid material 14 from the annular space between them and 9 to the solids outlet 4. If this flow is achieved in this way, the total height of the vessel 1 will be the same as it would be if a single steep frusto-conical wall structure were employed to obtain reliable flow of the granular contacting solid material. It is reduced more than it is.

The annular space 7 passes through the louver hole of the cylindrical wall member 6.
between the lower end of the wall member 9 and the inner surface of the frusto-conical member 27 to ensure that the granular solid material that has fallen to the bottom of the wall runs down and flows out of the outlet 4 without accumulating in the annular space 7. The distance b is approximately 10 of the distance a between the wall member 6, the lower end and the inner surface of the frusto-conical member 27.
Do not exceed double. In other words, the wall member 9
of the vessel to a point sufficiently lower than the lower end of wall member 6 that the line joining the lower ends of wall member 6 and wall member 9 has an angle with the horizontal that is steeper than the angle of repose of the particulate contacting solid material. It must extend down inside. The above line connects a point on the lower end of wall member 9 to wall member 6.
Of course, it is the shortest line that will connect the given points on the lower end of .

To further facilitate the flow of the contact material from the annular space 7 to the solids outlet 4, the lower part of the cylindrical wall member 6 is bent inward at the bottom 29. The purpose and effect of this bending will be explained in more detail with reference to FIG.

4 and 5 show details of the louvered surface of the first cylindrical wall member 6 and a cross-section of the louvered wall. The surface of this cylindrical wall member is perforated by staggered rows of louvers 24 as shown. The louver vanes 25 are inclined outwardly from the surface wall member 6 at an angle of about 15 to 80 degrees, preferably 30 to 50 degrees, relative to the vertical. The louver holes 26 are large enough to allow passage of essentially all of the particles making up the population of contacting solid material 14. The walls of the second cylindrical wall member are similarly louvered, but the louver vanes project inwardly from the second cylindrical wall member. 2.54 to 12.7
The millimeter (0.1 to 0.5 inch) louvered holes provide the desired small volume for most applications to replenish the contacting solid material population of particles ranging in size from approximately 2 mm to 12 mm in diameter. I like it because it helps maintain flow. Since the louver vane is formed by punching a hole in the cylindrical wall, the upper end of the louver vane is below the top of the louver aperture by a distance d that varies depending on the angle of the vane.

Many gases that contain suspended entrained solids and can be treated in accordance with the present invention to remove those solids have high water vapor contents ranging up to about 30 percent by weight. ing. When gases of this nature are processed, it is necessary to maintain the temperature inside the vessel 1 and the particulate contact material 14 above the dew point of the feed gas. In order to maintain a temperature above the dew point within the separator, it is desirable to insulate the lower part of the elevator 10, the first solids handling device 11, and at least the lower frusto-conical portion shown in FIG. It is.

FIG. 6 is a detailed view of the lower part of the cylindrical wall member 6.
The contact solid material fills the annular space between both cylindrical wall members 6 and 9 and the annular space between the wall of the container 1 and the cylindrical wall member 6 as a result of the contact solid material passing through the louvers of the cylindrical wall member 6. Flow from the annular space 7 to the bottom of the container when the filter is mounted with a cylindrical wall member 6 as a vertical wall terminating in the bottom of the container in a vertical direction with an edge between the contact solid material accumulated in the And finally the flow of contacting material leaving the solids outlet 4 is very slow. The contacting solid material has a tendency to accumulate in the annular space 7 and therein it blocks the louvered holes in the lower part of the louvered wall element 6.
As a result, the area of the louvered wall element 6 through which the incoming feed gas can pass to come into contact with the contacting solid material located between the two wall elements 6 and 9 is reduced. What is known is that the lower part of the louver-shaped wall member 6 [50.8 to 152.4 mm (2
This problem is solved by bending the 20- to 70-degree angle of the 20- to 70-degree angle. This bent portion is illustrated as 29. Lower part 50.8 to 152.4 of louver-shaped wall member 6
Instead of bending millimeters (2 to 6 inches) inward, a rigid metal plate (not shown) is attached to the bottom of the wall member 6 tilted inward at 20 to 70 degrees to the vertical. I don't mind. Flow is improved as desired if the wall members 6 are bent as shown, or if rigid plates angled inwardly are installed. This bent part of the louvered wall element 6 (indicated as 29) is placed between the contacting solid material between the two cylindrical wall members 6 and 9 and the contacting solid material accumulated in the annular space 7. The effect is annular space 7
The purpose is to allow the accumulated contact solid material to flow freely to the bottom of the container and out of the solids outlet 4. Annular space 7
Accumulation of solid material in contact with the cylindrical wall member 6 and the consequent blocking of the louvre holes in the lower part of the cylindrical wall member 6 is prevented.

FIG. 7 shows a cross-sectional detail of the annular mass of contacting solid material and both support walls along the central section of the container. The size of the particulate contacting solid material filling the space between the two cylindrical wall members 6 and 9 can be varied depending on the nature of the feed material. If the finely divided solid particles contained in the feed are very small, it is preferred to use relatively small particulate solid materials, such as 6 to 8 US sieve size. During the use of contacting solid materials of smaller particle size, semi-fluidization of the contacting material particles in the vicinity of the cylindrical wall member 9 and resulting in a sudden flow of the contacting material particles through the louvers of the wall member 9 occurs. Originating difficulties are being experienced. Once this rapid flow of contact material passes through the louvers, the cylindrical wall member 9
The contact material particles will accumulate at the bottom inside the
Particles that accumulate inside this and block the louvre holes in the lower part of the cylindrical wall part 9 therefore reduce the effective use of the real part of the contact material in the lower part of the annular space between the two cylindrical wall parts 6 and 9. do. If this builds up, the operation must be interrupted periodically to remove the accumulated contact material, thus reducing the operating coefficient. The problem of contacting solid material of small particle size passing through the louvered holes in wall member 9 in this manner is that the third cylindrical wall member having a diameter of 25.4 to 254 millimeters (1 to 10 inches) greater than the diameter of cylindrical wall member 9 is removed from the container. This problem is solved by placing the wall members 6 and 9 between the inner wall members. The surface of the third cylindrical wall member is perforated with pores of sufficient size to permit passage of essentially all particles of the contacting solid material; These pores, which are distributed over the entire surface of the member 18, extend over a large portion of the same surface, but are similar to the wall member 18.
At the upper end of the wall member 9, the highest perforation terminates at a point just over 100 millimeters (several inches) below the highest louver vane of the wall member 9. As a result of employing wall member 18 as described above, fluidization of contacting solid material particles is eliminated and the flow rate through the louvers of wall member 9 is reduced, resulting in an increase in the operating coefficient of the filter.

FIG. 8 is a detailed view of the upper part of the container showing the relative positioning of the louver holes in the wall member 6 to the position of the louver holes in the cylindrical wall member 9. FIG. Both wall members 6 and 9 are louvered so that wall member 6
The sudden flow of contacting solid material through the upper louver in wall member 9 when the container is configured such that the uppermost louver in wall member 9 is oriented opposite the top louver in wall member 9. was observed. This rapid flow results in a build-up of contacting solid material within the cylindrical wall member 9, which collects at a rate that slows the exit of this material through the slot 16 and flows through the wall member 9. This will cover the louver hole at the bottom of the. The observed rapid flow of contacting solid material through the upper louvers of wall member 9 is due to the fact that the feed gas entering the mass of contacting material 14 through the upper louvers of wall member 6 simply travels horizontally through the louvers of wall member 9. This is believed to be due to the fact that it not only escapes through the holes, but also passes upwardly through the contact material above the louvered portions of both wall members. This upward progression continues until the pressure resistance of the contacting material causes the feed gas to deflect downward and eventually escape through the upper louver of the wall member 9. As a result, the flow rate of gas through the upper louvers of the wall member 9 is much greater than the flow rate through the louvers in the middle part of the wall member 9. This large flow of gas simply passes through the upper louver of wall member 9, entraining an excess of contacting solid material. This difficulty obstructs the louver at the top of the wall member 6, and the remaining top louver on the wall member 6 is approximately
152.4 to 457.2 mm (6 to 18 inches)
Preferably within the range of about 304.8 mm (12
This arrangement of the vertical relative positions of the louvers at the top of both wall members 6 and 9 was overcome by having the louvers at the top of both wall members 6 and 9 be below the top louver of wall member 9 by a distance of The non-louvered solid surface thus constitutes the upper part of the wall element 6 and this non-louvered surface faces the upper louvered surface of the wall element 9. This arrangement of the relative vertical positions of the top louvers on both wall members 6 and 9 results in wall member 9
The rapid flow of contact solid material through the upper louver and the accumulation of this overflow material inside the cylindrical wall member 9 is prevented and the accumulated contact solid material is removed from the interior of the cylindrical wall member 9. However, interrupting the operation with a reduction in the operating coefficient has been made unnecessary.

OPERATION Gases containing finely divided solids and which can be treated to remove solids in accordance with the present invention come from a variety of sources. Stack gases from waste fuel fired boilers and gas streams containing suspended entrained solids formed in cement plants or lime kilns are examples of feed materials. Separation is effective whether the density of finely ground suspended solids is high or low, and solids having a diameter of about 0.5 microns are effectively separated.

The materials making up the mass of particulate contact solid material through which the feed gas is passed preferably have rounded rather than rounded edges to facilitate flow and to prevent bridging. and must be temperature-resistant at the temperature of the feed gas;
And the particles of the same material should have a reasonable uniformity of particle size. Particle size preferably ranges from about 2 millimeters in diameter to 12.5 millimeters in diameter. A population of particles in which the largest substantial amount of particles present has a diameter no greater than 3 to 4 times the diameter of the smallest substantial amount of particles present is considered a reasonably homogeneous population, and Shows good flow properties in separators. Coarse beach sand or finely ground gravel is cheap, readily available, and constitutes an excellent contact mass. 8% of US sieve size No.6, US sieve size No.7
62% and US sieve size No.8 30%
The San Simeon sand content is satisfactory coarse beach sand. US sieve size
66% of No.4 particles and US sieve size No.5
The fine gravel containing 26% of the particles and the remainder being slightly larger than No. 4 and slightly smaller than No. 6 is suitable fine gravel for use in the treatment. If gases at very high temperatures are to be treated, metal grains, ceramic or quartz beads and similar materials that are more resistant to temperature cracking than sand or gravel should be used as contact solid materials. .

The flow rate of the feed gas through the particulate solid mass typically ranges from about 15.25 meters (50 feet) to 61 meters (200 feet) per minute. This speed range is not critical and the speed can be varied over a considerable range as production target levels and separation efficiency change.

The pressure that descends to pass through a mass of granular solid material is typically 50.8 millimeters (50 inches) of water.
and approximately 304.8 millimeters (12 inches). Although separation efficiency is usually increased with higher pressure drops, this is achieved at the expense of increasing the energy required to force the feed gas through the separator.

In addition to varying the rate at which the feed gas is passed through the mass of particulate solid material in a device of the above type, the velocity at which the particulate solid is moved downward through the annular space between the two louvered cylindrical wall members can also be varied. I can do it.
Granular solids approximately 0.15 meters (0.5 feet) per hour
It can be moved at speeds within the range of 12.2 meters (40 feet) and can only be moved intermittently. High flow rates are employed for feed gases containing large amounts of finely divided solids. Low flow rates, or intermittent flow where the particles may be in motion for only one-sixth of the operating period, may be used if the feed gas contains a small amount of finely ground solids, or if the feed gas contains very little finely ground solids. can be employed when it is desired to remove a high content.

The method and apparatus of the present invention can be operated over a wide range of pressures. in stack gases at near atmospheric pressure or in gases emitted from coal gasifiers or waste incineration plants that may be present at concentrations of 7 kilograms per square centimeter (100 pounds per square inch) or higher; Finely divided solids can be effectively removed.

A model separator with a design capacity of 1133 cubic meters (40000 cubic feet) per minute is the Hog.
It was installed at a sawmill in Washington, U.S., to treat the stack gas coming out of the power room boiler that burns fuel. The device was similar in overall design to the first one except that the gas inlet was located approximately halfway between the top and bottom of the container and the bottom of the container had a double tapered conical bottom as shown in FIG. This corresponded to the design shown in the figure. The adopted granular solid material has a size of
It was 3.175 to 6.35 mm (1/8 to 1/4 inch). When installed, the device
It did not have the form shown in FIGS. 7 and 8. The annular population of granular solid material is 457.2
It had a thickness of millimeters (18 inches) and a height of 4.88 meters (16 feet). The rate at which the mass of granular solid material flows downwardly through the annular space between the two cylindrical wall members 6 and 9 shown in FIG.
It was 0.305 meters (1 foot). At this speed, a small portion of the particulate solid material is transferred to the cylindrical wall member 6.
A slow steady flow passes through the louvers of the second cylindrical wall member 9 into the annular space 7 and from there to the bottom of the vessel, and particulate solids pass through the louvers of the second cylindrical wall member 9 and into the space enclosed by the same wall member. There was a similar slow stream falling into a conical enclosure at the bottom. The flow of particulate solids through the louvers kept the louvered surfaces clean without depositing finely divided solids entrained in the feed gas. No louver blockage or significant increase in pressure drop due to build-up of solids contained in the feed gas was experienced.

During operation of this and other equipment, as well as during operation of test-scale equipment,
No problems with the improvements described with reference to Figures and Figure 8 were observed. Either by changing the flow velocity of the solid particles passing down the annular space between the two louvered cylindrical wall members 6 and 9, as shown in FIG. 1, or by reducing the gas supply rate. Or by both, it was possible to deal with the problem to such an extent as to make it possible to avoid frequent pauses. Addressing these problems in this manner was clearly insufficient. Reducing the gas flow rate reduced the effective capacity of the equipment, and circulating the solid particles faster increased processing costs because an unnecessarily large amount of particulate solid material was moved.

The filtration device improvements described with respect to FIGS. 6 and 8 have been tested in industrial-scale devices, and the improvements in FIG. 7 have been tested in pilot-scale devices;
The above problems have been solved and smooth steady state operation has been achieved in removing finely divided solid particles from the gas.

[Brief explanation of the drawing]

1 is an elevational view with the interior of the separation device shown in the cutaway portion of the same figure; FIG. 2 is a horizontal sectional view taken along line 2--2 of the separation vessel shown in FIG. 3
The Figures are an elevational view showing the internal details of the separation vessel shown in Figure 1 in a cutaway section of the figure; Figure 4 shows the louvered walls of the wall containing the mass of granular material; 5 is a cross-sectional view of the louvered cylindrical surface shown in FIG. 4 along line 5--5; FIG. 6 is a detailed view of the lower interior of the container. , FIG. 7 is a detailed view of the granular contact solid material held by both louvered cylindrical walls, and FIG. 8 is a detailed view of the contact material mass held at the top of the container by both cylindrical walls FIG. 1... "Container", 2... "Gas inlet", 3...
"Gas outlet", 4... "Solid outlet", 5... "Solid inlet", 6... "First wall member", 7... "Annular space between the first wall member and the wall of the container" , 9... "Second
"Wall member", 14... "Particulate contact solid material", 25...
..."louver blade", 26..."louver hole".

Claims (1)

Claims: 1. An apparatus for separating finely divided solids from a gas, comprising: (a) a generally cylindrical container having a gas inlet and a gas outlet on its surface; (b) one inside with respect to each other; a finely ground solid material consisting of an elongated mass of granular contacting solid material disposed between two concentric cylindrical walls, the other being an outer wall, and disposed between said gas inlet and said gas outlet; a filtration element used to separate the filtration element from the outer cylindrical wall, the outer cylindrical wall having a louvered surface formed by perforating the wall to form outwardly projecting louvered vanes; The inner cylindrical wall has a louvered surface formed by perforating the wall to form inwardly projecting louvered vanes, the louvered vanes of both cylindrical walls being approximately at an angle relative to the vertical line. angled between 15 degrees and 80 degrees, the louvered holes in both cylinder walls are large enough to allow essentially all of the contacting solid material particles to pass through the louvered holes; The upper surface of the wall is such that the louvered portion of the wall on the gas outlet side is close to the gas inlet side sufficiently to prevent excessive contact solid material from being entrained in the gas and escaping through the louvered holes in the wall on the gas outlet side. The louvered portion extends above the louvered portion of the wall so that the non-louvered non-porous surface of the upper portion of the wall on the gas inlet side faces the upper louvered surface of the wall on the gas outlet side. Apparatus for separating finely ground solids from gases, characterized in that: 2. In the device according to claim 1,
A third perforated cylindrical wall having a diameter of 1 to 10 inches (2.54 to 25.4 cm) greater than the diameter of the inner wall is disposed between the inner wall and the outer wall; Apparatus for separating finely divided solids from gas, characterized in that the pores in the cylindrical wall of are sufficiently large to allow substantially all of the contacting solid material particles to pass through the pores.