CYCLONE SEPARATOR WITH TWO GAS OUTLETS AND SEPARATION METHOD

Description

FIELD OF THE INVENTION

[0001] This invention is concerned with equipment and methods for separating solid particles from gas-particle suspensions. More particularly, the invention relates to cyclone separators, in which a tangential force component is imparted to the gas-particle suspension.

BACKGROUND OF THE INVENTION

[0002] Cyclone separators in various different constructional forms are used in a number of apparatuses for separating impurities contained in gaseous fluids, such as solid particles or dust, droplets of liquids or similar material.

[0003] Cyclone separators are also widely used for separating and for removing particles from the air or from process gases. They are also used as chemical reactors, heat exchangers and for drying granular materials and combustion of oil. In petroleum refineries, they are used for ensuring the continuity of the process for obtaining products, retaining a catalyst and impeding its emission into the atmosphere, preventing loss and pollution, so as to guarantee the continuity of the process. The great applicability of cyclone separators is at least in part due to their low operating cost, easy maintenance and the possibility of withstanding severe temperature and pressure conditions.

[0004] Cyclone separators can be used in various different arrangements, in series or in parallel. In some processes, all of the gaseous fluid produced, which shall hereinafter be called gas-particle suspension, passes through the separator. In other processes, cyclone separators can be used as part of a waste gas cleaning system.

[0005] The particles are separated by a process of centrifugation of the gas-particle suspension. This phenomenon occurs with the induction of a vortical flow inside the cyclone separator due to the significant tangential force component with which the suspension enters the cyclone chamber, which is generally of a conical-cylindrical shape. Being of greater density than the gases, the solid particles have a greater tendency to remain in the trajectory perpendicular to the vortical flow, due to centrifugal force and thus to collide with the walls of the chamber. With the collisions, the particles lose speed and tend to separate from the flow, falling towards the bottom of the chamber, from where they are removed. The gas separated is sucked out through the outlet pipe of the cyclone, after moving in several revolutions through the chamber and in a curve with an accentuated angle towards the outlet pipe in the upper part.

[0006] Cyclone separators of gas-particle suspensions are generally of the reverse flow type, which are the most conventional ones for this type of separation. However, unidirectional flow cyclones are also used, principally in applications where the concentration of particles in the suspension is low.

[0007] In reverse flow cyclones, the gas outlet pipe, usually called the finder or vortex pipe, is fixed and located in the upper part of the cyclone. During operation, there is a need for the total reversal of the vortical flow of the gas so that it is sucked by the outlet pipe.

[0008] In unidirectional flow cyclones (also known as "uniflow" cyclones), the gas outlet pipe is located in the lower part of the cyclone separator, there consequently not being a need for reversal of the vortical flow.

[0009] The unidirectional flow separator typically has a separation zone length shorter than that of a separator with reverse flow, this being the reason why the unidirectional flow separator is usually efficient only in gas-particle suspensions with low concentrations of solids.

[0010] Although the separation zone of the reverse flow separator is larger, the flow reversal zone is the region in which the greatest loss of collection efficiency of the cyclone separator occurs, due to the instability existing at the flow reversal apex, which is the moment at which the vortical flow is reversed from descending to ascending. This results in lateral displacements of the vortical flow, which causes entrainment of solids previously separated and erosion of the cyclone separator walls.

[0011] Patent US 4,238,210 discloses a unidirectional cyclone separator which comprises an internal duct, which forms a flow path, with a central body provided with swirl-generating vanes extending outwardly. The duct is enclosed by a collecting chamber and the vanes have collecting ends and channels which open through the wall of the duct to the inside of the collecting chamber. Downstream from the swirl-generating vanes, there are outlet slots which are transverse with respect to the gas flow.

[0012] As with the other unidirectional cyclone separators, this equipment is efficient only for suspensions with low concentrations of particles.

[0013] Patent application PI0803051-0, owned by the applicant, discloses a cyclone separator and a gas-particle separation method with two separation zones in sequence, one with reverse flow, in which a portion of the gas of the gas-particle suspension with a high concentration of solids is separated and a subsequent, unidirectional, flow separation zone in which the other portion of the gas of the suspension, with a low concentration of solids, is separated.

[0014] The cyclone separator is provided with two outlet pipes, one being fastened axially to the upper part and the other one being fastened axially to the lower part, generating the separation zones with reverse flow and unidirectional flow respectively.

[0015] Another cyclone separator according to the preamble of claim 1 as well as a method of separating particles from a mixture of gas and particles according to the preamble of claim 12 is disclosed in document WO 2010/001097 A1.

[0016] The apparatus and method described below have advantages for the separation of gas-particle suspensions, using reverse flow cyclones, with respect to the devices and methods known in the prior art, for example, the apparatus and method described below prevents the problems of loss of collection efficiency and erosion in the region of reversal of the vortical flow from descending to ascending.

SUMMARY OF THE INVENTION

[0017] This invention relates to a cyclone separator for a gas-particle suspension. The invention also relates to a separation method in which a separator as described herein is used. Where any reference is made herein to a "particle", this may be, by way of non-limitative example, a liquid particle or a solid particle. Thus, a gas-particle mixture or suspension may be a gas-solid mixture or suspension, a gas-liquid mixture or suspension, or a gas-solid-liquid mixture or suspension.

[0018] According to an aspect of the invention, there is provided a cyclone separator for separating particles from a mixture of gas and particles, according to claim 1.

[0019] According to an embodiment, in operation, the mass flow rate of gas exiting via the reverse flow gas outlet is over 70% of the total mass flow rate of gas exiting from the cyclone separator.

[0020] According to an embodiment, in operation, the mass flow rate of gas exiting via the reverse flow gas outlet is over 95% of the total mass flow rate of gas exiting from the cyclone separator.

[0021] According to an embodiment, the diameter of the unidirectional gas flow outlet is less than 30% of the diameter of the reverse flow gas outlet.

[0022] According to an embodiment, the diameter of the unidirectional gas flow outlet is in the range of from 1% to 5% of the diameter of the reverse flow gas outlet.

[0023] According to an embodiment, the shape of a cross section of the reverse flow gas outlet perpendicular to the gas flow direction is circular; and/or
the shape of a cross section of the unidirectional flow gas outlet perpendicular to the gas flow direction is circular.

[0024] According to an embodiment, the reverse flow gas outlet extends into the separation chamber so as to draw separated gas from inside the separation chamber; and/or
the unidrectional flow gas outlet extends into the separation chamber so as to draw separated gas from inside the separation chamber.

[0025] According to an embodiment, the cyclone separator further comprises a solids outlet configured to allow particles, which have been separated from the gas, to exit from the separation chamber, the solids outlet optionally being aligned with the unidirectional flow gas outlet.

[0026] According to an embodiment, at least a part of the separation chamber has an axial centreline, and the inlet either:

is substantially parallel to the axial centreline;

is substantially perpendicular to the axial centreline; or

forms a scroll around the axis centreline.

[0027] According to an embodiment, at least a part of the separation chamber has an axial centreline, and the inlet is offset from the axial centreline.

[0028] According to an embodiment, the cyclone separator further comprises a second inlet configured to allow the mixture of particles and gas into the separation chamber.

[0029] According to an embodiment, at least a part of the separation chamber has an axial centreline and the second inlet is either:

substantially parallel to the axial centreline;

substantially perpendicular to the axial centreline; or

forms a scroll around the axis centreline.

[0030] According to an embodiment: the separation chamber has an inlet end;

the inlet and reverse flow gas outlet are provided at said inlet end; and

the unidirectional gas outlet is provided at an end of the separation chamber that is opposite to the inlet end.

[0031] According to an embodiment: the gas exits the reverse flow gas outlet in a first exit flow direction; and
the gas exits the unidirectional flow gas outlet in a second exit flow direction, the first exit flow direction being different to the second exit flow direction. According to an embodiment, the first exit flow direction is substantially opposite to the second exit flow direction.

[0032] According to an embodiment, at least a portion of the separation chamber is radially symmetric about an axial centreline of the separation chamber.

[0033] According to an embodiment: the reverse flow gas outlet comprises a pipe having its centreline substantially aligned with the axial centreline of the separation chamber, and/or
the unidirectional flow gas outlet comprises a pipe having its centreline substantially aligned with the axial centreline of the separation chamber.

[0034] According to an embodiment, at least a portion of the inner wall of the separation chamber is frusto-conical.

[0035] According to an aspect of the invention, there is provided a method of separating particles from a mixture of gas and particles using a cyclone separator as described herein.

[0036] According to an aspect of the invention, there is provided a method of separating particles from a mixture of gas and particles according to claim 12.

[0037] According to an embodiment, the mass flow rate of gas removed through the reverse flow gas outlet is over 70% of the total mass flow rate of gas exiting from the cyclone separator.

[0038] According to an embodiment, the mass flow rate of gas removed through the reverse flow gas outlet is over 95% of the total mass flow rate of gas exiting from the cyclone separator.

[0039] According to an embodiment, the gas that is not removed through the reverse flow gas outlet is removed through the unidirectional flow gas outlet.

[0040] According to an embodiment, the position at which the flow direction is reversed is inside the unidirectional flow gas outlet.

[0041] According to an embodiment, the portion of gas removed via the reverse flow gas outlet is removed in a substantially opposite direction to the portion of gas removed via the unidirectional flow gas outlet.

[0042] According to an embodiment, the step of separating the mixture comprises centrifugal separation.

[0043] According to an embodiment, the method further comprises removing solids separated from the mixture.

[0044] According to an embodiment, the concentration of particles in the mixture provided to the separation chamber is greater than 1 gm^-3.

[0045] According to an embodiment, there is provided a reverse cyclone separator of gas-solid suspension, which comprises a cyclone chamber, with at least one inlet, an annular space for the collection of separated particles and two outlet pipes, one pipe being fastened axially to the upper part of the cyclone chamber and the other pipe being fastened axially to the lower part of the chamber and with an inside diameter in the range between 1% and 5% of the inside diameter of the upper pipe, both pipes having an axial extension into the chamber.

[0046] According to an embodiment, there is provided a method of gas-particle separation using the separator described above which comprises the stages of letting the gas-particle suspension into the chamber by means of the inlet, sucking out the gas separated, by means of the two pipes at the same time and, through an annular space, removing the separated solid particles, characterised in that a fraction of gas in proportions exceeding 95% is sucked out by the upper pipe and the complementary fraction is sucked out by the lower pipe, so as to maintain the reversal apex inside the lower pipe and stabilise the vortical flow. This method may stabilise the ascending vortical flow. The descending flow may be stabilised by the wall of the cyclone chamber. The method may also comprise imparting a tangential force component to the gas-particle suspension so as to separate the suspension.

[0047] The method may let the gas-solid suspension into the cyclone chamber by means of the (first) inlet and at least one additional inlet positioned symmetrically with the (first) inlet.

BRIEF DESCRIPTION OF THE DRAWINGS

[0048] The features of the cyclone separator of a gas-particle suspension and a separation method, which are the object of this invention, will be perceived better from the detailed description, provided by way of example only, associated with the illustration referenced below, which is an integral part of this specification.

Fig. 1 gives a perspective cutaway representation of the cyclone separator for a gas-particle suspension in a configuration with two inlets according to an embodiment of the invention, as well as a schematic representation of the separation method using the cyclone separator according to an embodiment of the invention.

Fig. 2 gives a perspective representation of a cyclone separator for a gas-particle suspension in a configuration with two inlets according to an embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

[0049] This invention discloses a cyclone separator for a gas-particle suspension. Also disclosed is a separation method in which the separator is capable of maintaining the stability of the ascending vortical flow during the separation process.

[0050] According to an embodiment, the cyclone separator comprises a cyclone chamber (1) (which may be referred to as a separation chamber (1)), with at least one inlet (11a), an annular space (13) for the collection of separated particles and two outlet pipes, one (upper) pipe (2) being fastened axially to the upper part of the cyclone chamber (1) and the other (lower) pipe (3) being fastened axially to the lower part of the chamber (1), both pipes having an axial extension into the chamber (1).

[0051] In this configuration, in a manner different from the prior art, the lower pipe (3) (which may also be referred to as an unidirectional flow gas outlet (3)) has an inside diameter that is smaller, for example significantly and/or considerably smaller, than the inside diameter of the upper pipe (2) (which may also be referred to as an reverse flow gas outlet (2)). For example, the inside diameter of the lower pipe (3) may be in the range of from 0.1% to less than 50% of the inside diameter of the upper pipe (3). Preferably, the inside diameter of the lower pipe (3) may be in the range of from 1% to 40% of the inside diameter of the upper pipe (2). Preferably, the inside diameter of the lower pipe (3) may be in the range of from 2% to 35% of the inside diameter of the upper pipe (2). Preferably, the inside diameter of the lower pipe (3) may be in the range of from 5% to 30% of the inside diameter of the upper pipe (2). Preferably, the inside diameter of the lower pipe (3) may be in the range of from 10% to 25% of the inside diameter of the upper pipe (2), for example around 22.4%. In an embodiment, the inside diameter of the lower pipe (3) may be in the range of from 15 to 20% of the inside diameter of the upper pipe (2).

[0052] The upper pipe (2) and the lower pipe (3), may take any suitable shape, for example in cross section. In an embodiment, the cross sectional shape of the upper pipe (2) is circular and the cross sectional shape of the lower pipe (3) is circular. However, any cross sectional shape may be used for the upper pipe (2) and the lower pipe (3). For example, the cross sectional shape could be a polygon, such as a regular polygon, for example a triangle, a square, a pentagon, or a hexagon. Alternatively, the cross sectional shape may be irregular. The cross sectional shape of the upper pipe (2) and the lower pipe (3) may be the same as each other or different to each other. The cross sectional shape and/or dimension of one or both of the upper pipe (2) and the lower pipe (3) may be the same along its length, or may change along its length. Indeed, although the term "pipe" is used herein with regard to the upper pipe (2) and the lower pipe (3), it will be appreciated that any suitable outlets (for example gas outlets) configured to allow gas to exit the separation chamber (1) could be used at the location of the upper pipe (2) and the lower pipe (3).

[0053] It will therefore be understood that where the term "diameter" is used herein, this should not be limiting on the shape of the upper pipe (2) or lower pipe (3). For example, where ranges of the relative diameter of the upper pipe (2) and lower pipe (3) are given, such ranges also disclose ranges of relative areas of the upper pipe (2) and the lower pipe (3) with any cross sectional shape that correspond to the area ratios of circular upper (2) and lower (3) pipes with the given diameter ratios. In other words, the relative areas of the upper and lower pipes may be in ranges corresponding to the diameter ranges given herein, regardless of the cross sectional shape of the upper pipe (2) and lower pipe (3).

[0054] For example, regardless of the shape of the pipes, the flow area of the lower pipe (3) may be less than 50% of the flow area of the upper pipe (2). In an embodiment, the flow area of the lower pipe (3) may be in the range of from 0.1% to 30% of the flow area of the upper pipe (2). In an embodiment, the flow area of the lower pipe (3) may be in the range of from 0.2% to 20% of the flow area of the upper pipe (2). In an embodiment, the flow area of the lower pipe (3) may be in the range of from 0.5% to 10% of the flow area of the upper pipe (2). In an embodiment, the flow area of the lower pipe (3) may be in the range of from 1% to 5% of the flow area of the upper pipe (2). In an embodiment, the flow area of the lower pipe (3) may be around 2.5% of the flow area of the upper pipe (2).

[0055] Regardless of the cross sectional shape of the upper pipe (2) and the lower pipe (3), the mass flow rate of gas extracted through the upper pipe (2) may be greater than the mass flow rate of gas extracted through the lower pipe (3). This may be achieved by any suitable means for example, it may be achieved by having the cross sectional area (which may be referred to as the flow area) of the upper pipe (2) (or reverse flow gas outlet) greater than the cross sectional area of the lower pipe (3) (or unidirectional flow gas outlet). In an embodiment, the cross sectional area of the upper pipe (2) may be significantly and/or considerably greater than the cross sectional area of the lower pipe (3). In this case, the vast majority of the gas (from which the particles have been separated) is extracted through the upper pipe (2), such that the cyclone separator acts as, or acts substantially as, a reverse flow cyclone separator.

[0056] The diameter of the lower pipe (3) may be less than 50% of the diameter of the upper pipe (2). In an embodiment, the diameter of the lower pipe (3) may be in the range of from 0.1% to 30% of the diameter of the upper pipe (2). In an embodiment, the diameter of the lower pipe (3) may be in the range of from 0.2% to 20% of the diameter of the upper pipe (2). In an embodiment, the diameter of the lower pipe (3) may be in the range of from 0.5% to 10% of the diameter of the upper pipe (2). In an embodiment, the diameter of the lower pipe (3) may be in the range of from 1% to 5% of the diameter of the upper pipe (2). In an embodiment, the diameter of the lower pipe (3) may be around 2.5% of the diameter of the upper pipe (2).

[0057] For the purposes of references the cross sectional areas, diameters and shapes of the examples used herein, any suitable location along the respective outlet may be used. For example, the cross sectional area and/or diameter and/or shape at the entrance to the respective outlet may be used. The cross-sectioned area and/or diameter and/or shape at the point along the respective outlet where the suction pressure acts on the exit may be used.

[0058] The method of gas-particle separation using the separator described above comprises the stages of letting the gas-particle suspension into the chamber (1) by means of the inlet (11a), and imparting a tangential force component to the gas-particle suspension. The tangential force component of the gas-particle suspension may be provided by swirling, or rotating, the gas-particle suspension inside the chamber (1) by any suitable means. In this way, the gas-particle suspension may be separated, or substantially separated, for example into a gaseous (or predominantly gaseous) phase or portion, and a particle (or predominantly particle) phase or portion. As mentioned above, the particle phase may be solid, liquid, or a mixture of solid and liquid.

[0059] In an embodiment of gas-particle separation using the cyclone separator according to the present invention, the method (which is also a part of the invention) may include removing (for example sucking out) the gas separated from the gas-particle suspension by means of the upper pipe (2) and the lower pipe (3). The gas may be sucked out, or removed, from the chamber (1), from both the upper pipe (2) and the lower pipe (3) at the same time. The separated particles (for example the solid phase, or portion) may be removed through a particles (or solids) outlet. In Fig. 1, such a solids outlet is shown as an annular solids outlet (13).

[0060] According to the apparatus and method of the present invention, a higher fraction of gas may be removed, or sucked out, by the upper pipe (2). This may, for example, maintain the position of the reversal apex inside the lower pipe (3) and thereby stabilise the vortical flow. In an embodiment of the invention, more than 50% of the gas may be removed, or sucked out, by the upper pipe (2). The remainder may be sucked out by the lower pipe (3). Preferably, the proportion of gas removed, or sucked out, by the upper pipe (2) is in the range of from 60% to 99%, the remainder being removed, or sucked out, by the lower pipe (3). Preferably, the proportion of gas removed, or sucked out, by the upper pipe (2) is in the range of from 70% to 98%, the remainder being removed, or sucked out, by the lower pipe (3). Preferably, the proportion of gas removed, or sucked out, by the upper pipe (2) is in the range of from 80% to 97%, the remainder being removed, or sucked out, by the lower pipe (3). Preferably, the proportion of gas removed, or sucked out, by the upper pipe (2) is in the range of from 90% to 96%, the remainder being removed, or sucked out, by the lower pipe (3). In an embodiment, the proportion of gas that is removed, or sucked out, by the upper pipe (2) exceeds 95%, with the remainder being removed, or sucked out by the lower pipe (3). The relative portions removed from the two gas outlets described above may equate to the relative mass flow rates in the two outlets.

[0061] In an embodiment of the invention, such as that shown in Fig. 1, the upper pipe (2) is provided at the same end of the separation chamber (1) as the inlet (11a) of the two-phase mixture (which may also be referred to as a gas-particle suspension or mixture). The separation chamber (1) may have a longitudinal axis, and the upper pipe (2) may be provided at, or towards, the same axial end of the separation chamber (1) as the inlet (11a). The lower pipe (3) may be provided at an end of the separation chamber (1) that is opposite (for example at the opposite end on a longitudinal axis of the separation chamber (1)) to the inlet (11a).

[0062] According to an embodiment of the invention, the upper pipe (2), in operation, receives a portion of the gas whose direction has been reversed inside the separation chamber (1). As such, the upper pipe (2) may be referred to as a reverse flow gas outlet (2), as stated above. Still alternatively, the upper pipe (2) may be referred to as an upper outlet (2) or a first gas outlet (2).

[0063] The lower pipe (3), in operation, is configured to receive a portion of the gas from the separation chamber (1) whose direction has not been reversed in the separation chamber (1). In other words, the lower pipe (3) may be configured such that the gas-particle suspension flows from the inlet (11a) to the lower pipe (3) without having its direction (for example axial direction) reversed, with at least some of the particles being separated from the gas-particle suspension as it flows from the inlet (11a) to the lower pipe (3). As such, the lower pipe (3) may be referred to as a unidirectional flow gas outlet (3), as stated above. Alternatively, the lower pipe (3) may be referred to as a lower outlet (3) or as a second gas outlet (3).

[0064] According to an arrangement of cyclone separator of the present invention, the reversal of the vortical flow from descending towards the lower pipe (3) to ascending towards the upper pipe (2) can be controlled so as to be far removed from the internal walls of the separation chamber (1). For example, the apex (or position) of the reversal of the vortical flow from descending towards the lower pipe (3) to ascending towards the upper pipe (2) may be inside the lower pipe (3), or near to the entrance of the lower pipe (3). This may be achieved, for example, by setting the relative diameters and/or areas of the upper pipe (2) and the lower pipe (3) to be in the proportions described herein. Alternatively or additionally, the position or apex of the reversal of the vortical flow may be controlled in embodiments of the present invention by controlling the relative fraction of gas removed by the upper pipe (2) and the lower pipe (3) (for example the relative mass flow rates through the the upper pipe (2) and the lower pipe (3)) to be in the proportions described herein.

[0065] By controlling the apex (or position) of the reversal of the vortical flow from descending to ascending to be far away from the internal walls of the separation chamber (1), the present invention can reduce entrainment, by the gas, of solid particles that have already been separated from the gas-particle suspension. An additional, or alternative, advantage is that by controlling the apex (or position) of the reversal of the vortical flow to be far away from the internal walls of the separation chamber (1), erosion of the separation chamber internal walls can be reduced or prevented.

[0066] This gas-particle separation apparatus and method of the present invention is suitable for separating suspensions with a wide range of concentrations of solid. For example, the method may be particularly suitable for separating suspensions with concentrations of solid exceeding 1 g/m³. The method and apparatus of the present invention is capable of being used individually or as a stage of equipment which has multiple cyclone separators connected together, for example in series.

[0067] The cyclone separator of the present invention may be provided with one inlet (11a) through which the gas-particle suspension enters into the separation chamber (1). Other embodiments may have more than one inlet through which the gas-particle suspension enters the separation chamber (1). For example, there may be 2, 3, 4 or more than 4 inlets into the separation chamber (1). Fig. 1 shows an example of the present invention which has one inlet (11a) and an additional inlet (11b). Fig.2 also shows such an embodiment. In the example shown in Fig. 2 (and indeed Fig. 1), the additional inlet (11 b) is positioned with its axis diametrically opposite to the axis of the first inlet (11a). In other words, the additional inlet (11b) is positioned to be diametrically opposite to, or symmetric with, the first inlet (11a).

[0068] The apparatus and method of the present invention have a number of advantages over the prior art. For example the apparatus and method of the present invention have the following advantages at least:

i. substantial reduction of the erosion in the lower region of the separator, the erosion being caused by the instability of the vortical flow in the region of the apex during reversal of the flow from descending to ascending in conventional cyclone separators,

ii. maintenance of the separation efficiency throughout the length of the path taken by the gas-particle suspension, and

iii. reduction of the entrainment, by the gas, of solid material already separated.

[0069] The description which has so far been given of this separation method must be considered only as one possible embodiment and any particular features must be understood as being described only to assist understanding. This being the case, the description herein should not be interpreted as limiting the scope of the invention, which is defined in the claims.

Claims

1. A cyclone separator for separating particles from a mixture of gas and particles, said cyclone separator comprising:

a separation chamber (1) in which the particles are separated from the gas;

an inlet configured to provide the mixture of particles and gas to the separation chamber;

a reverse flow gas outlet (2) positioned to receive a portion of the gas, from which particles have been separated, from the separation chamber, the direction of this portion of the gas having been reversed in the separation chamber, the reverse flow gas outlet extends into the separation chamber so as to draw separated gas from inside the separation chamber; and

a unidirectional flow gas outlet (3) positioned to receive another portion of the gas, from which particles have been separated, from the separation chamber, the direction of this portion of the gas not having been reversed in the separation chamber,

characterised in that:

the flow area of the reverse flow gas outlet is greater than the flow area of the unidirectional flow gas outlet, such that, in operation, the mass flow rate of gas exiting via the reverse flow gas outlet is greater than the mass flow rate of gas exiting via the unidirectional flow gas outlet.

2. A cyclone separator according to claim 1, wherein:

in operation, the mass flow rate of gas exiting via the reverse flow gas outlet is over 70% of the total mass flow rate of gas exiting from the cyclone separator; or

in operation, the mass flow rate of gas exiting via the reverse flow gas outlet is over 95% of the total mass flow rate of gas exiting from the cyclone separator.

3. A cyclone separator according to any one of the preceding claims, wherein:

the diameter of the unidirectional gas flow outlet is less than 30% of the diameter of the reverse flow gas outlet; and/or

the diameter of the unidirectional gas flow outlet is in the range of from 1% to 5% of the diameter of the reverse flow gas outlet.

4. A cyclone separator according to any one of the preceding claims, wherein:

the shape of a cross section of the reverse flow gas outlet perpendicular to the gas flow direction is circular; and/or

the shape of a cross section of the unidirectional flow gas outlet perpendicular to the gas flow direction is circular; and/or

the unidirectional flow gas outlet extends into the separation chamber so as to draw separated gas from inside the separation chamber; and/or

the cyclone separator further comprises a solids outlet configured to allow particles, which have been separated from the gas, to exit from the separation chamber, the solids outlets optionally being aligned with the unidirectional flow gas outlet.

5. A cyclone separator according to any one of the preceding claims, wherein at least a part of the separation chamber has an axial centreline, and the inlet either:

is substantially parallel to the axial centreline;

is substantially perpendicular to the axial centreline; or

forms a scroll around the axis centreline.

6. A cyclone separator according to any one of the preceding claims, wherein:

at least a part of the separation chamber has an axial centreline, and the inlet is offset from the axial centreline; and/or

at least a portion of the inner wall of the separation chamber is frusto-conical.

7. A cyclone separator according to any one of the preceding claims, further comprising a second inlet configured to allow the mixture of particles and gas into the separation chamber;
wherein optionally at least a part of the separation chamber has an axial centreline and the second inlet is either:

substantially parallel to the axial centreline;

substantially perpendicular to the axial centreline; or

forms a scroll around the axis centreline.

8. A cyclone separator according to any one of the preceding claims, wherein:

the separation chamber has an inlet end;

the inlet and reverse flow gas outlet are provided at said inlet end; and

the unidirectional gas outlet is provided at an end of the separation chamber that is opposite to the inlet end.

9. A cyclone separator according to any one of the preceding claims, wherein:

the gas exits the reverse flow gas outlet in a first exit flow direction; and

the gas exits the unidirectional flow gas outlet in a second exit flow direction, the first exit flow direction being different to the second exit flow direction;

wherein optionally the first exit flow direction is substantially opposite to the second exit flow direction.

10. A cyclone separator according to any one of the preceding claims, wherein at least a portion of the separation chamber is radially symmetric about an axial centreline of the separation chamber;
wherein optionally:

the reverse flow gas outlet comprises a pipe having its centreline substantially aligned with the axial centreline of the separation chamber, and/or

the unidirectional flow gas outlet comprises a pipe having its centreline substantially aligned with the axial centreline of the separation chamber.

11. A method of separating particles from a mixture of gas and particles using the cyclone separator of any one of claims 1 to 10.

12. A method of separating particles from a mixture of gas and particles, said method comprising:

providing the mixture to a separation chamber (1);

reversing the flow direction of a portion of the gas;

allowing another portion of the gas to continue without reversing its flow direction;

removing the portion of gas whose direction has not been reversed via a unidirectional flow gas outlet (3), wherein the reverse flow gas outlet extends into the separation chamber so as to draw separated gas from inside the separation chamber; and

removing the portion of gas whose direction has been reversed via a reverse flow gas outlet (2),

characterised in that:

the flow area of the reverse flow gas outlet is greater than the flow area of the unidirectional flow gas outlet, and the mass flow rate of gas removed through the reverse flow gas outlet is greater than the mass flow rate of gas removed through the unidirectional flow gas outlet.

13. A method of separating particles from a mixture of gas and particles according to claim 12, wherein:

the mass flow rate of gas removed through the reverse flow gas outlet is over 70% of the total mass flow rate of gas exiting from the cyclone separator; or

the mass flow rate of gas removed through the reverse flow gas outlet is over 95% of the total mass flow rate of gas exiting from the cyclone separator.

14. A method of separating particles from a mixture of gas and particles according to any one of claims 12 to 13, wherein:

the gas that is not removed through the reverse flow gas outlet is removed through the unidirectional flow gas outlet; and/or

the position at which the flow direction is reversed is inside the unidirectional flow gas outlet; and/or

the portion of gas removed via the reverse flow gas outlet is removed in a substantially opposite direction to the portion of gas removed via the unidirectional flow gas outlet; and/or

the step of separating the mixture comprises centrifugal separation; and/or

the method further comprises removing solids separated from the mixture.

15. A method of separating particles from a mixture of gas and particles according to any one of claims 11 to 14, wherein the concentration of particles in the mixture provided to the separation chamber is greater than 1 gm^-3.

Ansprüche

1. Zyklonabscheider zur Abscheidung von Partikeln aus einer Mischung aus Gas und Partikeln, wobei der Zyklonabscheider Folgendes umfasst:

eine Abscheidekammer (1), in der die Partikel aus dem Gas abgeschieden werden; einen Einlass, der zur Versorgung der Abscheidekammer mit der Mischung aus Partikeln und Gas ausgebildet ist;

einen Gegenstrom-Gasauslass (2), der zur Aufnahme eines Teils des Gases aus der Abscheidekammer angeordnet ist, aus dem Partikel abgeschieden wurden, wobei die Richtung dieses Teils des Gases in der Abscheidekammer umgekehrt wurde, wobei sich der Gegenstrom-Gasauslass (2) in die Abscheidekammer erstreckt, um abgeschiedenes Gas aus dem Inneren der Abscheidekammer abzuziehen; und

einen Einwegstrom-Gasauslass (3), der zur Aufnahme eines anderen Teils des Gases aus der Abscheidekammer angeordnet ist, aus dem Partikel abgeschieden wurden, wobei die Richtung dieses Teils des Gases nicht in der Abscheidekammer umgekehrt wurde,

dadurch gekennzeichnet,

dass der Strömungsquerschnitt des Gegenstrom-Gasauslasses größer ist als der Strömungsquerschnitt des Einwegstrom-Gasauslasses, so dass der Massendurchsatz des durch den Gegenstrom-Gasauslass austretenden Gases im Betrieb höher ist als der Massendurchsatz des durch den Einwegstrom-Gasauslass austretenden Gases.

2. Zyklonabscheider nach Anspruch 1, wobei:

der Massendurchsatz des durch den Gegenstrom-Gasauslass austretenden Gases im Betrieb mehr als 70 % des gesamten Massendurchsatzes des aus dem Zyklonabscheider austretenden Gases beträgt; oder

der Massendurchsatz des durch den Gegenstrom-Gasauslass austretenden Gases im Betrieb mehr als 95 % des gesamten Massendurchsatzes des aus dem Zyklonabscheider austretenden Gases beträgt.

3. Zyklonabscheider nach einem der vorangehenden Ansprüche, wobei:

der Durchmesser des Einwegstrom-Gasauslasses weniger als 30 % des Durchmessers des Gegenstrom-Gasauslasses beträgt; und/oder der Durchmesser des Einwegstrom-Gasauslasses zwischen 1 % und 5 % des Durchmessers des Gegenstrom-Gasauslasses beträgt.

4. Zyklonabscheider nach einem der vorangehenden Ansprüche, wobei:

die Form eines Querschnitts des Gegenstrom-Gasauslasses senkrecht zur Gasströmungsrichtung kreisförmig ist; und/oder

die Form eines Querschnitts des Einwegstrom-Gasauslasses senkrecht zur Gasströmungsrichtung kreisförmig ist; und/oder

der Einwegstrom-Gasauslass sich in die Abscheidekammer erstreckt, um abgeschiedenes Gas aus dem Inneren der Abscheidekammer abzuziehen; und/oder der Zyklonabscheider weiterhin einen Feststoffauslass umfasst, der dazu ausgebildet ist, aus dem Gas abgeschiedene Partikel aus der Abscheidekammer austreten zu lassen, wobei die Feststoffauslässe optional mit dem Einwegstrom-Gasauslass verbunden sind.

5. Zyklonabscheider nach einem der vorangehenden Ansprüche, wobei zumindest ein Teil der Abscheidekammer eine axiale Mittellinie aufweist und der Einlass entweder:

im Wesentlichen parallel zu der axialen Mittellinie verläuft;

im Wesentlichen senkrecht zu der axialen Mittellinie verläuft; oder

einen Kranz (scroll) um die axiale Mittellinie bildet.

6. Zyklonabscheider nach einem der vorangehenden Ansprüche, wobei:

zumindest ein Teil der Abscheidekammer eine axiale Mittellinie aufweist und der Einlass gegenüber der axialen Mittellinie versetzt ist; und/oder zumindest ein Teil der Innenwand der Abscheidekammer kegelstumpfförmig ist.

7. Zyklonabscheider nach einem der vorangehenden Ansprüche, weiterhin umfassend einen zweiten Einlass, der dazu ausgebildet ist, die Mischung aus Partikeln und Gas in die Abscheidekammer einzulassen;
wobei optional zumindest ein Teil der Abscheidekammer eine axiale Mittellinie aufweist und der zweite Einlass entweder:

im Wesentlichen parallel zu der axialen Mittellinie verläuft;

im Wesentlichen senkrecht zu der axialen Mittellinie verläuft; oder

einen Kranz (scroll) um die axiale Mittellinie bildet.

8. Zyklonabscheider nach einem der vorangehenden Ansprüche, wobei:

die Abscheidekammer ein Einlassende aufweist;

der Einlass und der Gegenstrom-Gasauslass an dem Einlassende vorgesehen sind; und

der Einwegstrom-Gasauslass an einem dem Einlassende gegenüberliegenden Ende der Abscheidekammer angeordnet ist.

9. Zyklonabscheider nach einem der vorangehenden Ansprüche, wobei:

das Gas in einer ersten Austrittsströmungsrichtung aus dem Gegenstrom-Gasauslass austritt; und

das Gas in einer zweiten Austrittsströmungsrichtung aus dem Einwegstrom-Gasauslass austritt, wobei sich die erste Austrittsströmungsrichtung von der zweiten Austrittsströmungsrichtung unterscheidet;

wobei die erste Austrittsströmungsrichtung der zweiten Austrittsströmungsrichtung optional im Wesentlichen entgegengesetzt ist.

10. Zyklonabscheider nach einem der vorangehenden Ansprüche, wobei zumindest ein Teil der Abscheidekammer radialsymmetrisch um eine axiale Mittellinie der Abscheidekammer verläuft;
wobei optional:

der Gegenstrom-Gasauslass ein Rohr umfasst, dessen Mittellinie im Wesentlichen mit der axialen Mittellinie der Abscheidekammer fluchtet, und/oder der Einwegstrom-Gasauslass ein Rohr umfasst, dessen Mittellinie im Wesentlichen mit der axialen Mittellinie der Abscheidekammer fluchtet.

11. Verfahren zum Abscheiden von Partikeln aus einer Mischung aus Gas und Partikeln mittels des Zyklonabscheiders nach einem der Ansprüche 1 bis 10.

12. Verfahren zum Abscheiden von Partikeln aus einer Mischung aus Gas und Partikeln, wobei das Verfahren folgende Schritte umfasst:

Versorgen einer Abscheidekammer (1) mit der Mischung;

Umkehren der Strömungsrichtung eines Teils des Gases;

Weiterlassen eines anderen Teils des Gases ohne Umkehrung der Strömungsrichtung;

Entfernen des Gasteils, dessen Richtung nicht umgekehrt wurde, über einen Einwegstrom-Gasauslass (3), wobei sich der Gegenstrom-Gasauslass in die Abscheidekammer erstreckt, um abgeschiedenes Gas aus dem Inneren der Abscheidekammer abzuziehen; und

Entfernen des Gasteils, dessen Richtung umgekehrt wurde, über einen Gegenstrom-Gasauslass (2),

dadurch gekennzeichnet,

dass der Strömungsquerschnitt des Gegenstrom-Gasauslasses größer ist als der Strömungsquerschnitt des Einwegstrom-Gasauslasses und dass der Massendurchsatz des durch den Gegenstrom-Gasauslass entfernten Gases höher ist als der Massendurchsatz des durch den Einwegstrom-Gasauslass entfernten Gases.

13. Verfahren zum Abscheiden von Partikeln aus einer Mischung aus Gas und Partikeln nach Anspruch 12, wobei:

der Massendurchsatz des durch den Gegenstrom-Gasauslass entfernten Gases mehr als 70 % des gesamten Massendurchsatzes des aus dem Zyklonabscheider austretenden Gases beträgt; oder

der Massendurchsatz des durch den Gegenstrom-Gasauslass entfernten Gases mehr als 95 % des gesamten Massendurchsatzes des aus dem Zyklonabscheider austretenden Gases beträgt.

14. Verfahren zum Abscheiden von Partikeln aus einer Mischung aus Gas und Partikeln nach einem der Ansprüche 12 bis 13, wobei:

das nicht durch den Gegenstrom-Gasauslass entfernte Gas durch den Einwegstrom-Gasauslass entfernt wird; und/oder

die Position, an der die Strömungsrichtung umgekehrt wird, innerhalb des Einwegstrom-Gasauslasses liegt; und/oder

der durch den Gegenstrom-Gasauslass entfernte Teil des Gases in einer dem durch den Einwegstrom-Gasauslass entfernten Teil des Gases im Wesentlichen entgegengesetzten Richtung entfernt wird; und/oder

der Schritt des Trennens der Mischung eine Zentrifugaltrennung umfasst; und/oder das Verfahren weiterhin das Entfernen von aus der Mischung abgeschiedenen Feststoffen umfasst.

15. Verfahren zur Abscheidung von Partikeln aus einer Mischung aus Gas und Partikeln nach einem der Ansprüche 11 bis 14, wobei die Konzentration von Partikeln in der der Abscheidekammer zugeführten Mischung höher als 1 gm^-3 ist.

Revendications

1. Séparateur à cyclone pour séparer des particules d'un mélange de gaz et de particules, ledit séparateur à cyclone comprenant :

une chambre de séparation (1) dans laquelle les particules sont séparées du gaz ;

une entrée configurée pour fournir le mélange de particules et de gaz à la chambre de séparation ;

une sortie de gaz d'écoulement inverse (2) positionnée pour recevoir une partie du gaz, de laquelle les particules ont été séparées, de la chambre de séparation, la direction de cette partie du gaz ayant été inversée dans la chambre de séparation, la sortie de gaz d'écoulement inverse s'étend dans la chambre de séparation de manière à aspirer le gaz séparé de l'intérieur de la chambre de séparation ; et

une sortie de gaz d'écoulement unidirectionnel (3) positionnée pour recevoir une autre partie du gaz, de laquelle les particules ont été séparées, de la chambre de séparation, la direction de cette partie du gaz n'ayant pas été inversée dans la chambre de séparation,

caractérisé en ce que :

la section d'écoulement de la sortie de gaz d'écoulement inverse est plus grande que la section d'écoulement de la sortie de gaz d'écoulement unidirectionnel, de sorte que, en fonctionnement, le débit massique du gaz sortant par la sortie de gaz d'écoulement inverse est supérieur au débit massique du gaz sortant par la sortie de gaz d'écoulement unidirectionnel.

2. Séparateur à cyclone selon la revendication 1, dans lequel :

en fonctionnement, le débit massique du gaz sortant par la sortie de gaz d'écoulement inverse dépasse 70 % du débit massique total du gaz sortant du séparateur à cyclone ; ou

en fonctionnement, le débit massique du gaz sortant par la sortie de gaz d'écoulement inverse dépasse 95 % du débit massique total du gaz sortant du séparateur à cyclone.

3. Séparateur à cyclone selon l'une quelconque des revendications précédentes, dans lequel :

le diamètre de la sortie d'écoulement de gaz unidirectionnel est inférieur à 30 % du diamètre de la sortie de gaz d'écoulement inverse ; et/ou

le diamètre de la sortie d'écoulement de gaz unidirectionnel est dans la plage de 1 % à 5 % du diamètre de la sortie de gaz d'écoulement inverse.

4. Séparateur à cyclone selon l'une quelconque des revendications précédentes, dans lequel :

la forme d'une section transversale de la sortie de gaz d'écoulement inverse perpendiculaire à la direction d'écoulement de gaz est circulaire ; et/ou

la forme d'une section transversale de la sortie de gaz d'écoulement unidirectionnel perpendiculaire à la direction d'écoulement de gaz est circulaire ; et/ou

la sortie de gaz d'écoulement unidirectionnel s'étend dans la chambre de séparation de manière à aspirer le gaz séparé de l'intérieur de la chambre de séparation ; et/ou

le séparateur à cyclone comprend en outre une sortie de solides configurée pour permettre aux particules, qui ont été séparées du gaz, de sortir de la chambre de séparation, les sorties de solides étant, optionnellement, alignées avec la sortie de gaz d'écoulement unidirectionnel.

5. Séparateur à cyclone selon l'une quelconque des revendications précédentes, dans lequel au moins une partie de la chambre de séparation a une ligne centrale axiale, et l'entrée :

soit est sensiblement parallèle à la ligne centrale axiale ;

soit est sensiblement perpendiculaire à la ligne centrale axiale ; ou

soit forme une volute autour de la ligne centrale axiale.

6. Séparateur à cyclone selon l'une quelconque des revendications précédentes, dans lequel :

au moins une partie de la chambre de séparation a une ligne centrale axiale, et l'entrée est décalée par rapport à la ligne centrale axiale ; et/ou

au moins une partie de la paroi interne de la chambre de séparation est conique tronquée.

7. Séparateur à cyclone selon l'une quelconque des revendications précédentes, comprenant en outre une deuxième entrée configurée pour permettre au mélange des particules et du gaz d'entrer dans la chambre de séparation ;
dans lequel, optionnellement, au moins une partie de la chambre de séparation a une ligne centrale axiale et la deuxième entrée :

soit est sensiblement parallèle à la ligne centrale axiale ,

soit est sensiblement perpendiculaire à la ligne centrale axiale ;

soit forme une volute autour de la ligne centrale axiale.

8. Séparateur à cyclone selon l'une quelconque des revendications précédentes, dans lequel :

la chambre de séparation a une extrémité d'entrée ;

l'entrée et la sortie de gaz d'écoulement inverse sont prévues au niveau de ladite extrémité d'entrée ; et

la sortie de gaz d'écoulement unidirectionnel est prévue à une extrémité de la chambre de séparation qui est à l'opposé de l'extrémité d'entrée.

9. Séparateur à cyclone selon l'une quelconque des revendications précédentes, dans lequel :

le gaz quitte la sortie de gaz d'écoulement inverse dans une première direction d'écoulement de sortie ; et

le gaz quitte la sortie de gaz d'écoulement unidirectionnel dans une deuxième direction d'écoulement de sortie, la première direction d'écoulement de sortie étant différente de la deuxième direction d'écoulement de sortie ;

dans lequel, optionnellement, la première direction d'écoulement de sortie est sensiblement opposée à la deuxième direction d'écoulement de sortie.

10. Séparateur à cyclone selon l'une quelconque des revendications précédentes, dans lequel au moins une partie de la chambre de séparation est radialement symétrique autour d'une ligne centrale axiale de la chambre de séparation ;
dans lequel optionnellement :

la sortie de gaz d'écoulement inverse comprend un tuyau dont la ligne centrale est sensiblement alignée avec la ligne centrale axiale de la chambre de séparation, et/ou

la sortie de gaz d'écoulement unidirectionnel comprend un tuyau dont la ligne centrale est sensiblement alignée avec la ligne centrale axiale de la chambre de séparation.

11. Procédé de séparation des particules d'un mélange de gaz et de particules en utilisant le séparateur à cyclone selon l'une quelconque des revendications 1 à 10.

12. Procédé de séparation des particules d'un mélange de gaz et de particules, ledit procédé comprenant :

la fourniture du mélange à une chambre de séparation (1) ;

l'inversion de la direction d'écoulement d'une partie du gaz ;

l'écoulement d'une autre partie du gaz sans inversion de sa direction d'écoulement ;

le retrait de la partie de gaz dont la direction n'a pas été inversée à travers une sortie de gaz d'écoulement unidirectionnel (3), dans lequel la sortie de gaz d'écoulement inverse s'étend dans la chambre de séparation de manière à aspirer le gaz séparé de l'intérieur de la chambre de séparation ; et

le retrait de la partie de gaz dont la direction a été inversée à travers une sortie de gaz d'écoulement inverse (2),

caractérisé en ce que :

la section d'écoulement de la sortie de gaz d'écoulement inverse est plus grande que la section d'écoulement de la sortie de gaz d'écoulement unidirectionnel, et le débit massique du gaz retiré à travers la sortie de gaz d'écoulement inverse est supérieur au débit massique du gaz retiré à travers la sortie de gaz d'écoulement unidirectionnel.

13. Procédé de séparation des particules d'un mélange de gaz et de particules selon la revendication 12, dans lequel :

le débit massique du gaz retiré à travers la sortie de gaz d'écoulement inverse dépasse 70 % du débit massique total du gaz sortant du séparateur à cyclone ; ou

le débit massique du gaz retiré à travers la sortie de gaz d'écoulement inverse dépasse 95 % du débit massique total du gaz sortant du séparateur à cyclone.

14. Procédé de séparation des particules d'un mélange de gaz et de particules selon l'une quelconque des revendications 12 et 13, dans lequel :

le gaz qui n'est pas retiré à travers la sortie de gaz d'écoulement inverse est retiré à travers la sortie de gaz d'écoulement unidirectionnel ; et/ou

la position à laquelle la direction d'écoulement est inversée est à l'intérieur de la sortie de gaz d'écoulement unidirectionnel ; et/ou

la partie de gaz retirée à travers la sortie de gaz d'écoulement inverse est retirée dans une direction sensiblement opposée à celle de la partie de gaz retirée à travers la sortie de gaz d'écoulement unidirectionnel ; et/ou

l'étape de séparation du mélange comprend une séparation centrifuge ; et/ou

le procédé comprend en outre le retrait des solides séparés du mélange.

15. Procédé de séparation des particules d'un mélange de gaz et de particules selon l'une quelconque des revendications 11 à 14, dans lequel la concentration de particules dans le mélange fourni à la chambre de séparation est supérieure à 1 gm-3

Drawing