CA2171892A1 - Downflow cyclone - Google Patents
Downflow cycloneInfo
- Publication number
- CA2171892A1 CA2171892A1 CA 2171892 CA2171892A CA2171892A1 CA 2171892 A1 CA2171892 A1 CA 2171892A1 CA 2171892 CA2171892 CA 2171892 CA 2171892 A CA2171892 A CA 2171892A CA 2171892 A1 CA2171892 A1 CA 2171892A1
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- CA
- Canada
- Prior art keywords
- cyclone
- outlet tube
- gas outlet
- inlet
- cross
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
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Abstract
There is described a downflow cyclone consisting of a coaxially arranged head portion (1), a cylindrical separ-ating chamber (2) and a conical settling chamber (3) as well as a raw gas inlet (4) and a gas outlet tube (6). The raw gas inlet (4) is disposed in the lower half of the cy-lindrical separating chamber (2). The ratio between height H2 and diameter D2 of the cylindrical separating chamber (2) lies in the range between 0.2:1 and 2.5:1. The gas out-let tube (6) protruding into the cyclone emerges laterally from the conical settling chamber (3) or concentrically through a line (9) for supplying solids, and the point where the gas flows into the gas outlet tube (6) lies be-tween two imaginary planes, the lower one of which lies be-low the lowest point of the cross-section of the raw gas inlet (8) and has a distance B from the lowest point of the cross-section of the raw gas inlet (8) which is equal to twice the diameter D1 of the gas outlet tube, and the upper one of which has a distance A from the head portion (1) which is equal to once the diameter D1 of the gas outlet tube.
Description
This invention relates to a downflow cyclone comprising a coaxially arranged head portion, a cylindrical separating chamber and a conical settling chamber as well as raw gas inlet and a gas outlet tube. In this cyclone, the gas stream and the stream of solids leave the separating cham-ber in parallel in downward direction, i.e. in a falling manner .
The cyclones operate in accordance with the principle of equilibrium, where dust-laden gas (raw gas) flows with a spin into an approximately cylindrical separating chamber, leaves the same again in radially inward direction through the separation surface, an imaginary extension of the gas outlet tube, and then flows axially through the gas outlet tube to the outside. In the process, the dust particles are acted upon by a centrifugal force, which throws the larger particles radially to the outside against the wall. The term gas is used here for any gas as well as mists and va-pors. The term dust is meant to include all kinds of parti-culate impurities which must be removed from the raw gas.The flow through the cyclone involves a loss of pressure, which is caused by the dissipation of energy when the gas flows into the gas outlet tube, which acts as a throttle.
Moreover, in addition to the main flows there are also pro-duced secondary flows, which above all deteriorate the se-paration results. This leads to a short-circuit flow along the gas outlet tube, caused by the cooperation of the pinch flow behind the usually present tangential gas inlet and the friction at the lid of the cyclone.
For reducing this short-circuit flow it was suggested to lead the gas inlet away from the lid, or to design the cy-clone as a dual cyclone. What is disadvantageous in these types of construction is the fact that moving the gas inlet away leads to an increase in the loss of pressure, and the design as a dual cyclone involves an additional structural effort. A further structural measure described is the de-sign as a continuous-flow cyclone comprising an inner discharge gap and a shielding plate, or comprising a slit immersion tube, an external discharge gap and a boundary layer counter-coil at the bottom. These structural measures are meant to prevent a direct penetration of dust at the separating surface of the lid into the clean gas ~Paul Schmidt, "Ungewohnliche Zyklonabscheider", Chemie-Ingeni-eur-Technik, 62 (1990), pp. 536 to 543). The above-de-scribed types of cyclone separators have the disadvantageof a high number of components required and an increased susceptibility to wear, and they can no longer be safely used at high operating temperatures.
For improving the separation of fine dust particles it was suggested in DE-PS 889 544 to provide conical inserts in a cyclone having a housing conically expanding in the flow direction of the dust-laden air. The raw gas stream enter-ing through a tangential tube leaves the separation chamber in the same direction through a bent gas outlet tube.
The DE-PS 598 423 describes a cyclone having a tangential gas inlet, which includes a downwardly directed gas outlet tube axially protruding into the separation chamber. At its end, the gas outlet tube is provided with an attachment `~ ~171 892 which is similar to a flange or forms an angle smaller than 90 with the wall of the tube.
A centrifugal separator group comprising a plurality of cy-clones arranged at the same level, which are connected in parallel and include an axial flow, is described in AT-PS
187 516. The raw gas chamber, the clean gas chamber and the dust chamber each extend over the entire group of centrifu-gal separators. The dust-discharging lines are located in the middle of the axis, and the gas outlet tube is bent.
Finally, the DE-PS 3 225 509 discloses a centrifugal separ-ator directly connected with a fluidized-bed reactor, which centrifugal separator has a tangential gas inlet and a gas outlet tube extending from the turbulence chamber. The gas outlet tube extends through the bottom of the turbulence chamber from below, and via an opening disposed at the lowest point of the bottom and a line connected thereto the solid matter is returned to the reactor.
The above-described cyclones all have the disadvantage that secondary flows may form at the point where the raw gas enters the separating chamber, so that dust is moved radi-ally through the separating surface to the inside and reaches the clean gas stream. In this way, the degree of separation, i.e. the amount of dust separated from the raw gas stream, is reduced.
It is the object of the present invention to improve the degree of separation of a downflow cyclone. In addition, it is the object of the present invention to provide a down-flow cyclone which can be used at comparatively high oper-ating temperatures, and where the structural effort and thus the manufacturing costs are kept low.
-~171892 The object underlying the invention is solved in that the raw gas inlet is disposed in the lower half of the cylind-rical separating chamber, that the height/diameter ratio of the cylindrical separating chamber lies in the range be-tween 0.2:1 and 2.5:1, that the gas outlet tube protruding into the cyclone emerges laterally from the conical sett-ling chamber or concentrically through a line for discharging solids, and that the point where the gas enters the gas outlet tube lies between two imaginary planes, the lower one of which lies below the lowest point of the cross-sec-tion of the raw gas inlet and has a distance from the lowest point of the cross-section of the raw gas inlet which is equal to twice the diameter of the gas outlet tube, and the upper one of which has a distance A from the head portion which is equal to once the diameter of the gas outlet tube.
The term "cyclindrical separating chamber" does not exclude that in this part of the cyclone there is already collected dust; the term "conical settling chamber" does not exclude that in this part of the cyclone there is still separated dust. It was noted that the cyclone in accordance with the invention leads to a considerably improved separation of solids. The position of the raw gas inlet in the lower half of the cylindrical separation chamber leads to the fact that there is no secondary flow at the raw gas inlet, so that a short-circuit flow, which would let dust get into the clean gas stream, is largely avoided. The degree of se-paration of the cyclone furthermore depends on the rubbing surface of the conical settling chamber: The smaller the conicity (angle of inclination with respect to the verti-cal), the larger is the degree of separation. However, the optimum angles of inclination depend on the properties of the material to be separated. An optimum angle of inclina-tion can be determined by means of a few simple tests.
- ~171892 In accordance with a preferred embodiment of the invention it is provided that the cross-section of the raw gas inlet be rectangular with a height/width ratio in the range be-tween 1:1 and 5:1.
In accordance with a further preferred embodiment of the invention it is provided that the height/diameter ratio of the cylindrical separation chamber be in the range between 1.1:1 and 1.5:1. The advantage is that there is achieved a comparatively high separation of solids.
In accordance with a further preferred embodiment of the invention it is provided that the conical settling chamber have a two-part design, comprising an upper, longer part with an angle of inclination of 2 to 10 and a lower, shorter part with an angle of inclination of 10 to 45O.
In accordance with a further preferred embodiment of the invention it is provided that the point where the gas enters the gas outlet tube be disposed between two imagi-nary planes, the lower one of which lies below the lowest point of the cross-section of the raw gas inlet and has a distance from the lowest point of the cross-section of the raw gas inlet which is equal to twice the diameter of the gas outlet tube, and the upper one of which lies above the lowest point of the cross-section of the raw gas inlet and has a distance from the lowest point of the cross-section of the raw gas inlet which is equal to once the diameter of the gas outlet tube. As a result, the loss of pressure of the gas in the cyclone is relatively small.
In accordance with a further preferred embodiment of the invention it is provided that in the conical settling cham-ber a shielding cone be provided. Due to the installation of a shielding cone, gas bubbles from the line for sup-plying solids are prevented from penetrating into the separation chamber of the cyclone. Moreover, such a cone has the advantage that it can additionally support the gas outlet tube at the wall of the cyclone.
In accordance with a further preferred embodiment of the invention it is provided that at the end of the conical settling chamber a line for discharging solids be disposed, through which the dust separated is discharged from the cy-clone.
In accordance with a further preferred embodiment of the invention it is provided that the flow of raw gas into the cyclindrical separating chamber be effected through a spi-ral inlet, a slotted inlet, a tubular inlet, an axial inlet or a helical inlet.
In accordance with a further preferred embodiment of the invention it is provided that the head portion of the cy-clone consist of a flat plate or a cupola.
In accordance with a further preferred embodiment of the invention it is provided that the gas outlet tube be straight and be arranged between the longitudinal axis of the gas outlet tube and the longitudinal axis of the cy-clone at an angle of 0 to 15. The advantage is a further simplication of the construction and a saving of costs. It is for instance easily possible to lay bricks around the gas outlet tubes.
In accordance with a further preferred embodiment of the invention it is provided that the point where the gas enters the gas outlet tube be arranged in the conical sett-ling chamber. Especially in the case of a cyclone having a relatively small height/diameter ratio of the cylindrical separating chamber this leads to a comparatively small loss " - 2171892 of pressure of the gas in the cyclone with a relatively high degree of separation of solids at the same time.
In accordance with a further preferred embodiment of the invention it is provided that the cyclone be used for cleaning dust-laden gases and gaseous substances, In accordance with a further preferred embodiment of the invention it is provided that the cyclone be used as a re-circulating cyclone in plants comprising a circulatingfluidized bed.
The subject-matter of the invention will subsequently be explained in detail with reference to the drawings (Fig. 1 and 2).
Fig. 1 shows a cross-section through the cyclone as well as a top view and a cross-section of the inlet passage for the raw gas.
Fig. 2 shows a cross-section through various embodiments of the cyclone comprising different head portions as well as a different type of gas outlet tube and conical settling chamber.
In Fig. 1 picture la represents a cross-section of the cy-clone. The cyclone comprises a head portion 1, a cyclindri-cal separating chamber 2 and a two-part conical settling chamber with a different conicity (angles ~1 and ~2) of the two parts 3a, 3b. The dust-laden raw gas flows into the cy-lindrical separating chamber 2 through the inlet passage 4 via the inlet 5. The cleaned gas leaves the separating chamber 2 through the gas outlet tube 6 with the diameter D1. The gas outlet tube 6 is provided with a shielding cone 7. Picture lb shows the rectangular inlet cross-section 8 of the raw gas with a ratio between height Hl and width Bl 217~892 of 4:1. Picture lc shows a top view of the rectangular in-let passage 4. The inlet passage 4 can be parallel (broken line) or have a conicity, i.e. an angle a of 0 to 10. The ratio of the height H2 to the diameter D2 of the cylindri-cal separating chamber 2 is 1:1. The point of entrance in the gas outlet tube is arranged at a distance A below the head portion 1 and at a distance B below the lowest point of the inlet cross-section 8. The line 9 for ~ l~rying so-lids is attached to the settling chamber 3a, 3b.
In Fig. 2 various embodiments of the head portion 1, the gas outlet tube 6 and the conical settling chamber 3 are represented. In Fig. 2a the cyclone comprises a flat plate as head portion 1. The gas outlet tube 6 extends up to the middle of the inlet cross-section 8 for the raw gas and ex-tends out of the conical settling chamber 3 in the shape of an arc. In Fig. 2b the cyclone comprises a dome-shaped head portion 1. In Fig. 2c the head portion 1 is dome-shaped.
The point of entrance into the gas outlet tube 6 lies at a distance C above the lowest point of the inlet cross-sec-tion 8 of the raw gas. A line 9 for discharging solids is at-tached to the conical settling chamber 3. In Fig. 2d the gas outlet tube 6 is straight and obliquely emerges from the conical settling chamber 3 with an angle between the longitudinal axis L1 of the gas outlet tube and the longi-tudinal axis L2 of the cyclone. The gas outlet tube 6 does not extend into the cylindrical separating chamber 2. Said cyclone has a ratio between height H2 and diameter D2 o~
the cylindrical separating chamber 2 of about 0.5:1. The point of entrance into the gas outlet tube 6 is arranged at a distance A below the head portion 1 and at a distance B
below the lowest point of the inlet cross-section 8.
It was noted that the cyclone in accordance with the inven-tion has an improved separation of solids as compared to a conventional cyclone. A further advantage in connection g with gas streams having a high solids content is its resis-tance to "infiltrated air" due to the course of flow of such gas streams. "Infiltrated air'~ is understood to be a stream of gas or air flowing through the line 9 for ~is.3.~
ing solids into the cyclone, countercurrently to the so-lids discharged. Such streams of infiltrated air are pro-duced in particular when a float chamber or a stationary fluidized bed are disposed below the cyclone. Part of the air used in these apparatuses for fluidizing the solids es-capes through the line 9 for discharging solids, where it canentrain particles already separated in the cyclone and re-turn them to the separating chamber 2. In addition, the stream of infiltrated air leads to a change in the pressure conditions in the separating chamber, which in general lead to a deterioration of the separating performance. Experi-ments with an inventive cyclone as compared to a conventio-nal cyclone have shown that the embodiment in accordance with the invention has considerable advantages in the case of streams of infiltrated air, as they are usually produced in plants having a circulating fluidized bed.
Therefore, a preferred field of application of the cyclone in accordance with the invention is its use in plants including a circulating fluidized bed.
The cyclones operate in accordance with the principle of equilibrium, where dust-laden gas (raw gas) flows with a spin into an approximately cylindrical separating chamber, leaves the same again in radially inward direction through the separation surface, an imaginary extension of the gas outlet tube, and then flows axially through the gas outlet tube to the outside. In the process, the dust particles are acted upon by a centrifugal force, which throws the larger particles radially to the outside against the wall. The term gas is used here for any gas as well as mists and va-pors. The term dust is meant to include all kinds of parti-culate impurities which must be removed from the raw gas.The flow through the cyclone involves a loss of pressure, which is caused by the dissipation of energy when the gas flows into the gas outlet tube, which acts as a throttle.
Moreover, in addition to the main flows there are also pro-duced secondary flows, which above all deteriorate the se-paration results. This leads to a short-circuit flow along the gas outlet tube, caused by the cooperation of the pinch flow behind the usually present tangential gas inlet and the friction at the lid of the cyclone.
For reducing this short-circuit flow it was suggested to lead the gas inlet away from the lid, or to design the cy-clone as a dual cyclone. What is disadvantageous in these types of construction is the fact that moving the gas inlet away leads to an increase in the loss of pressure, and the design as a dual cyclone involves an additional structural effort. A further structural measure described is the de-sign as a continuous-flow cyclone comprising an inner discharge gap and a shielding plate, or comprising a slit immersion tube, an external discharge gap and a boundary layer counter-coil at the bottom. These structural measures are meant to prevent a direct penetration of dust at the separating surface of the lid into the clean gas ~Paul Schmidt, "Ungewohnliche Zyklonabscheider", Chemie-Ingeni-eur-Technik, 62 (1990), pp. 536 to 543). The above-de-scribed types of cyclone separators have the disadvantageof a high number of components required and an increased susceptibility to wear, and they can no longer be safely used at high operating temperatures.
For improving the separation of fine dust particles it was suggested in DE-PS 889 544 to provide conical inserts in a cyclone having a housing conically expanding in the flow direction of the dust-laden air. The raw gas stream enter-ing through a tangential tube leaves the separation chamber in the same direction through a bent gas outlet tube.
The DE-PS 598 423 describes a cyclone having a tangential gas inlet, which includes a downwardly directed gas outlet tube axially protruding into the separation chamber. At its end, the gas outlet tube is provided with an attachment `~ ~171 892 which is similar to a flange or forms an angle smaller than 90 with the wall of the tube.
A centrifugal separator group comprising a plurality of cy-clones arranged at the same level, which are connected in parallel and include an axial flow, is described in AT-PS
187 516. The raw gas chamber, the clean gas chamber and the dust chamber each extend over the entire group of centrifu-gal separators. The dust-discharging lines are located in the middle of the axis, and the gas outlet tube is bent.
Finally, the DE-PS 3 225 509 discloses a centrifugal separ-ator directly connected with a fluidized-bed reactor, which centrifugal separator has a tangential gas inlet and a gas outlet tube extending from the turbulence chamber. The gas outlet tube extends through the bottom of the turbulence chamber from below, and via an opening disposed at the lowest point of the bottom and a line connected thereto the solid matter is returned to the reactor.
The above-described cyclones all have the disadvantage that secondary flows may form at the point where the raw gas enters the separating chamber, so that dust is moved radi-ally through the separating surface to the inside and reaches the clean gas stream. In this way, the degree of separation, i.e. the amount of dust separated from the raw gas stream, is reduced.
It is the object of the present invention to improve the degree of separation of a downflow cyclone. In addition, it is the object of the present invention to provide a down-flow cyclone which can be used at comparatively high oper-ating temperatures, and where the structural effort and thus the manufacturing costs are kept low.
-~171892 The object underlying the invention is solved in that the raw gas inlet is disposed in the lower half of the cylind-rical separating chamber, that the height/diameter ratio of the cylindrical separating chamber lies in the range be-tween 0.2:1 and 2.5:1, that the gas outlet tube protruding into the cyclone emerges laterally from the conical sett-ling chamber or concentrically through a line for discharging solids, and that the point where the gas enters the gas outlet tube lies between two imaginary planes, the lower one of which lies below the lowest point of the cross-sec-tion of the raw gas inlet and has a distance from the lowest point of the cross-section of the raw gas inlet which is equal to twice the diameter of the gas outlet tube, and the upper one of which has a distance A from the head portion which is equal to once the diameter of the gas outlet tube.
The term "cyclindrical separating chamber" does not exclude that in this part of the cyclone there is already collected dust; the term "conical settling chamber" does not exclude that in this part of the cyclone there is still separated dust. It was noted that the cyclone in accordance with the invention leads to a considerably improved separation of solids. The position of the raw gas inlet in the lower half of the cylindrical separation chamber leads to the fact that there is no secondary flow at the raw gas inlet, so that a short-circuit flow, which would let dust get into the clean gas stream, is largely avoided. The degree of se-paration of the cyclone furthermore depends on the rubbing surface of the conical settling chamber: The smaller the conicity (angle of inclination with respect to the verti-cal), the larger is the degree of separation. However, the optimum angles of inclination depend on the properties of the material to be separated. An optimum angle of inclina-tion can be determined by means of a few simple tests.
- ~171892 In accordance with a preferred embodiment of the invention it is provided that the cross-section of the raw gas inlet be rectangular with a height/width ratio in the range be-tween 1:1 and 5:1.
In accordance with a further preferred embodiment of the invention it is provided that the height/diameter ratio of the cylindrical separation chamber be in the range between 1.1:1 and 1.5:1. The advantage is that there is achieved a comparatively high separation of solids.
In accordance with a further preferred embodiment of the invention it is provided that the conical settling chamber have a two-part design, comprising an upper, longer part with an angle of inclination of 2 to 10 and a lower, shorter part with an angle of inclination of 10 to 45O.
In accordance with a further preferred embodiment of the invention it is provided that the point where the gas enters the gas outlet tube be disposed between two imagi-nary planes, the lower one of which lies below the lowest point of the cross-section of the raw gas inlet and has a distance from the lowest point of the cross-section of the raw gas inlet which is equal to twice the diameter of the gas outlet tube, and the upper one of which lies above the lowest point of the cross-section of the raw gas inlet and has a distance from the lowest point of the cross-section of the raw gas inlet which is equal to once the diameter of the gas outlet tube. As a result, the loss of pressure of the gas in the cyclone is relatively small.
In accordance with a further preferred embodiment of the invention it is provided that in the conical settling cham-ber a shielding cone be provided. Due to the installation of a shielding cone, gas bubbles from the line for sup-plying solids are prevented from penetrating into the separation chamber of the cyclone. Moreover, such a cone has the advantage that it can additionally support the gas outlet tube at the wall of the cyclone.
In accordance with a further preferred embodiment of the invention it is provided that at the end of the conical settling chamber a line for discharging solids be disposed, through which the dust separated is discharged from the cy-clone.
In accordance with a further preferred embodiment of the invention it is provided that the flow of raw gas into the cyclindrical separating chamber be effected through a spi-ral inlet, a slotted inlet, a tubular inlet, an axial inlet or a helical inlet.
In accordance with a further preferred embodiment of the invention it is provided that the head portion of the cy-clone consist of a flat plate or a cupola.
In accordance with a further preferred embodiment of the invention it is provided that the gas outlet tube be straight and be arranged between the longitudinal axis of the gas outlet tube and the longitudinal axis of the cy-clone at an angle of 0 to 15. The advantage is a further simplication of the construction and a saving of costs. It is for instance easily possible to lay bricks around the gas outlet tubes.
In accordance with a further preferred embodiment of the invention it is provided that the point where the gas enters the gas outlet tube be arranged in the conical sett-ling chamber. Especially in the case of a cyclone having a relatively small height/diameter ratio of the cylindrical separating chamber this leads to a comparatively small loss " - 2171892 of pressure of the gas in the cyclone with a relatively high degree of separation of solids at the same time.
In accordance with a further preferred embodiment of the invention it is provided that the cyclone be used for cleaning dust-laden gases and gaseous substances, In accordance with a further preferred embodiment of the invention it is provided that the cyclone be used as a re-circulating cyclone in plants comprising a circulatingfluidized bed.
The subject-matter of the invention will subsequently be explained in detail with reference to the drawings (Fig. 1 and 2).
Fig. 1 shows a cross-section through the cyclone as well as a top view and a cross-section of the inlet passage for the raw gas.
Fig. 2 shows a cross-section through various embodiments of the cyclone comprising different head portions as well as a different type of gas outlet tube and conical settling chamber.
In Fig. 1 picture la represents a cross-section of the cy-clone. The cyclone comprises a head portion 1, a cyclindri-cal separating chamber 2 and a two-part conical settling chamber with a different conicity (angles ~1 and ~2) of the two parts 3a, 3b. The dust-laden raw gas flows into the cy-lindrical separating chamber 2 through the inlet passage 4 via the inlet 5. The cleaned gas leaves the separating chamber 2 through the gas outlet tube 6 with the diameter D1. The gas outlet tube 6 is provided with a shielding cone 7. Picture lb shows the rectangular inlet cross-section 8 of the raw gas with a ratio between height Hl and width Bl 217~892 of 4:1. Picture lc shows a top view of the rectangular in-let passage 4. The inlet passage 4 can be parallel (broken line) or have a conicity, i.e. an angle a of 0 to 10. The ratio of the height H2 to the diameter D2 of the cylindri-cal separating chamber 2 is 1:1. The point of entrance in the gas outlet tube is arranged at a distance A below the head portion 1 and at a distance B below the lowest point of the inlet cross-section 8. The line 9 for ~ l~rying so-lids is attached to the settling chamber 3a, 3b.
In Fig. 2 various embodiments of the head portion 1, the gas outlet tube 6 and the conical settling chamber 3 are represented. In Fig. 2a the cyclone comprises a flat plate as head portion 1. The gas outlet tube 6 extends up to the middle of the inlet cross-section 8 for the raw gas and ex-tends out of the conical settling chamber 3 in the shape of an arc. In Fig. 2b the cyclone comprises a dome-shaped head portion 1. In Fig. 2c the head portion 1 is dome-shaped.
The point of entrance into the gas outlet tube 6 lies at a distance C above the lowest point of the inlet cross-sec-tion 8 of the raw gas. A line 9 for discharging solids is at-tached to the conical settling chamber 3. In Fig. 2d the gas outlet tube 6 is straight and obliquely emerges from the conical settling chamber 3 with an angle between the longitudinal axis L1 of the gas outlet tube and the longi-tudinal axis L2 of the cyclone. The gas outlet tube 6 does not extend into the cylindrical separating chamber 2. Said cyclone has a ratio between height H2 and diameter D2 o~
the cylindrical separating chamber 2 of about 0.5:1. The point of entrance into the gas outlet tube 6 is arranged at a distance A below the head portion 1 and at a distance B
below the lowest point of the inlet cross-section 8.
It was noted that the cyclone in accordance with the inven-tion has an improved separation of solids as compared to a conventional cyclone. A further advantage in connection g with gas streams having a high solids content is its resis-tance to "infiltrated air" due to the course of flow of such gas streams. "Infiltrated air'~ is understood to be a stream of gas or air flowing through the line 9 for ~is.3.~
ing solids into the cyclone, countercurrently to the so-lids discharged. Such streams of infiltrated air are pro-duced in particular when a float chamber or a stationary fluidized bed are disposed below the cyclone. Part of the air used in these apparatuses for fluidizing the solids es-capes through the line 9 for discharging solids, where it canentrain particles already separated in the cyclone and re-turn them to the separating chamber 2. In addition, the stream of infiltrated air leads to a change in the pressure conditions in the separating chamber, which in general lead to a deterioration of the separating performance. Experi-ments with an inventive cyclone as compared to a conventio-nal cyclone have shown that the embodiment in accordance with the invention has considerable advantages in the case of streams of infiltrated air, as they are usually produced in plants having a circulating fluidized bed.
Therefore, a preferred field of application of the cyclone in accordance with the invention is its use in plants including a circulating fluidized bed.
Claims (23)
1. A downflow cyclone comprising a coaxially arranged head portion (1), a cylindrical separating chamber (2) and a conical settling chamber (3) as well as a raw gas inlet (4) and a gas outlet tube (6), characterized in that the raw gas inlet (4) is disposed in the lower half of the cylindrical separating chamber (2), that the ratio be-tween height H2 and diameter D2 of the cylindrical separating chamber (2) lies in the range between 0.2:1 and 2.5:1, that the gas outlet tube (6) protruding into the cyclone emerges laterally from the conical settling chamber (3) or concentrically through a line (9) for dis-charging solids, and that the point where the gas flows into the gas outlet tube (6) lies between two imaginary planes, the lower one of which lies below the lowest point of the cross-section of the raw gas inlet (8) and has a distance B from the lowest point of the cross-sec-tion of the raw gas inlet (8) which is equal to twice the diameter D1 of the gas outlet tube, and the upper one of which has a distance A from the head portion (1) which is equal to once the diameter D1 of the gas outlet tube.
2. The cyclone as claimed in claim 1, characterized in that the cross-section of the raw gas inlet (8) is rectangu-lar with a ratio between height H1 and width B1 in the range between 1:1 and 5:1.
3. The cyclone as claimed in claim 1 or 2, characterized in that the ratio between height H2 and diameter D2 of the cylindrical separating chamber (2) lies in the range between 1.1:1 and 1.5:1.
4. The cyclone as claimed in claim 1, charac-terized in that the conical settling chamber t3) has a two-part design, comprising an upper, longer part (3a) with an angle of inclination .beta.1 of 2° to 10° and a lower, shorter part (3b) with an angle of inclination .beta.2 of 10° to 45°.
5. The cyclone as claimed in claim 1, charac-terized in that the point where the gas flows into the gas outlet tube (6) lies between two imaginary planes, the lower one of which lies below the lowest point of the cross-section of the raw gas inlet (8) and has a distance (B) from the lowest point of the cross-section of the raw gas inlet (8) which is equal to once the dia-meter D1 of the gas outlet tube, and the upper one of which lies above the lowest point of the cross-section of the raw gas inlet (8) and has a distance (C) from the lowest point of the cross-section of the raw gas inlet (8) which is equal to once the diameter D1 of the gas outlet tube.
6. The cyclone as claimed in claim 1, charac-terized in that a shielding cone (7) is disposed in the conical settling chamber (3).
7. The cyclone as claimed in claim 1, charac-terized in that at the end of the conical settling cham-ber (3) a line (9) for discharging solids is provided.
8. The cyclone as claimed in claim 1, charac-terized in that the raw gas flows into the cylindrical separating chamber (2) through a spiral inlet, a slotted inlet, a tubular inlet, an axial inlet or a helical in-let.
9. The cyclone as claimed in claim 1, charac-terized in that the head portion (1) consists of a flat plate or a cupola.
10. The cyclone as claimed in claim 1, characterized in that the gas outlet tube (6) is straight and is disposed between the longitudinal axis L1 of the gas outlet tube and the longitudinal axis L2 of the cyclone with an angle of 0° to 15°.
11. The cyclone as claimed in claim 1, characterized in that the point where the gas flows into the gas outlet tube (6) is disposed in the conical settling chamber (3).
12. The cyclone as claimed in claim 1, characterized in that the cyclone is used for cleaning dust-laden gases and gaseous substances.
13. The cyclone as claimed in claim 1, characterized in that the cyclone is used as a recirculating cyclone in plants comprising a circulating fluidized bed.
14. The cyclone as claimed in claim 3, characterized in that the conical settling chamber (3) has a two-part design, comprising an upper, longer part (3a) with an angle of inclination .beta.1 of 2° to 10° and a lower, shorter part (3b) with an angle of inclination .beta.2 of 10° to 45°.
15. The cyclone as claimed in claim 14, characterized in that the point where the gas flows into the gas outlet tube (6) lies between two imaginary planes, the lower one of which lies below the lowest point of the cross-section of the raw gas inlet (8) and has a distance (B) from the lowest point of the cross-section of the raw gas inlet (8) which is equal to once the diameter D1 of the gas outlet tube, and the upper one of which lies above the lowest point of the cross-section of the raw gas inlet (8) and has a distance (C) from the lowest point of the cross-section of the raw gas inlet (8) which is equal to once the diameter D1 of the gas outlet tube.
16. The cyclone as claimed in claim 15, characterized in that a shielding cone (7) is disposed in the conical settling chambe (3).
17. The cyclone as claimed in claim 16, characterized in that at the end of the conical settling chamber (3) a line (9 for dicharging solids is provided.
18. The cyclone as claimed in claim 17, characterized in that the raw gas flows into the cylindrical separating chamber (2) through a spiral inlet, a slotted inlet, a tubular inlet, an axial inlet or a helical inlet.
19. The cyclone as claimed in claim 18, characterized in that the head portion (1) consists of a flat plate or a cupola.
20. The cyclone as claimed in claim 19, characterized in that the gas outlet tube (6) is straight and is disposed between the longitudinal axis L1 of the gas outlet tube and the longitudinal axis L2 of the cyclone with an angle of 0° to 15°.
21. The cyclone as claimed in claim 20, characterized in that the point where the gas flows into the gas outlet tube (6) is disposed in the conical settling chamber (3).
22. The cyclone as claimed in claim 21, characterized in that the cyclone is used for cleaning dust-laden gases and gaseous substances.
23. The cyclone as claimed in claim 22, characterized in that the cyclone is used as a recirculating cyclone in plants comprising a circulating fluidized bed.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19509944.3 | 1995-03-18 | ||
| DE19509944 | 1995-03-18 | ||
| DE19606647.6 | 1996-02-23 | ||
| DE19606647A DE19606647C2 (en) | 1995-03-18 | 1996-02-23 | Downstream cyclone |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2171892A1 true CA2171892A1 (en) | 1996-09-19 |
Family
ID=26013504
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2171892 Abandoned CA2171892A1 (en) | 1995-03-18 | 1996-03-15 | Downflow cyclone |
Country Status (3)
| Country | Link |
|---|---|
| AU (1) | AU712201B2 (en) |
| BR (1) | BR9601044A (en) |
| CA (1) | CA2171892A1 (en) |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US1568413A (en) * | 1923-04-30 | 1926-01-05 | David D Peebles | Separator |
| US4221655A (en) * | 1978-03-03 | 1980-09-09 | Nippon Pneumatic Manufacturing Co., Ltd. | Air classifier |
| DK163745C (en) * | 1988-03-08 | 1992-09-07 | Smidth & Co As F L | HEAT EXCHANGE |
-
1996
- 1996-03-15 CA CA 2171892 patent/CA2171892A1/en not_active Abandoned
- 1996-03-15 AU AU48157/96A patent/AU712201B2/en not_active Ceased
- 1996-03-18 BR BR9601044A patent/BR9601044A/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| AU712201B2 (en) | 1999-10-28 |
| AU4815796A (en) | 1996-09-26 |
| BR9601044A (en) | 1998-01-06 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| FZDE | Dead |