Centrifugal separator

Description

[0001] The invention relates to a centrifugal separator with a conically widening separation chamber and an expansion chamber according to EP 0 676 599 A1.

[0002] Further centrifugal separators are known from JP 4 978875 B2, US 1 798 510 A and US 3 996 027 A.

[0003] From DE 10 2017 113 888 B3, centrifugal separators extending along a central axis with a separation chamber and an expansion chamber are known.

[0004] Such centrifugal separators are generally used to separate fluid phases of different densities (so-called light fraction or heavy fraction) of a multiphase fluid by separating the heavy fraction.

[0005] To achieve the separation effect, the multiphase fluid is fed into the separation chamber via an inlet channel and guided in such a way that a rotating flow develops within the separation chamber. The resulting centrifugal forces cause a radial acceleration, particularly of the heavy fraction, and the separation of the heavy fraction on the inside of a separation chamber wall.

[0006] After separation, the components of the heavy fraction are transported away and slide, primarily on spiral paths along the inside of the separation chamber wall, toward the expansion chamber until they are absorbed into the expansion chamber. There, the rotational movement slows down, and the heavy fraction is discharged from the centrifugal separator via an outlet channel connected to the expansion chamber.

[0007] The separation chamber of the centrifugal separator of DE 10 2017 113 888 B3 is designed to taper conically from the inlet channel toward the expansion chamber. The tapered separation chamber increases the rotational speed of the fluid along the central axis. This leads to an increase in the centrifugal forces acting on the fluid phases and to an improved separation efficiency.

[0008] The invention is based on the object of providing a centrifugal separator with a separation chamber which - while largely maintaining the separation effect of conventional centrifugal separators - enables an improved and more reliable removal of the denser fluid phase (heavy fraction) from the separation chamber.

[0009] This object is achieved by a centrifugal separator having the features of patent claim 1.

[0010] It was recognized that the centrifugal separator known from DE 10 2017 113 888 B3 has the disadvantage that the components of the heavy fraction separated on the inside of the separation chamber wall are subjected to a centrifugal force component that acts opposite to the desired direction of movement (i.e., in the direction of the inlet channel). This can lead to undesirable operating conditions during which components of the heavy fraction do not move toward the expansion chamber or the outlet channel, but remain on constant circular paths along the inside of the separation chamber wall or are even accelerated toward the inlet channel. The resulting lack of removal of the heavy fraction can lead to a buildup of the heavy fraction in the separation chamber and a collapse of the rotational flow.

[0011] Due to the conical expansion of the separation chamber, a component of the centrifugal force always acts on the heavy fraction components separated on the inside of the separation chamber wall in the direction of the expansion chamber or the outlet channel. This accelerates the separated heavy fraction components toward the expansion chamber during operation of the centrifugal separator, significantly increasing the removal rate from the separation chamber to the expansion chamber. In particular, this prevents the undesirable operating conditions mentioned above.

[0012] Surprisingly, it has been found that the separation efficiency of the centrifugal separator is maintained despite the deceleration of the fluid along the central axis associated with the conical expansion. The centrifugal forces acting on the heavy fraction remain sufficiently large to achieve a radial acceleration of the gravity fraction.

[0013] In a preferred embodiment, the angle of inclination of the separation chamber wall, measured relative to the central axis, is between 2° and 20°, in particular between 2.5° and 15°. This represents the optimal angular range at which the centrifugal force component is large enough to accelerate the denser phase (heavy fraction) toward the expansion chamber while simultaneously ensuring the formation of a stable rotational flow in the separation chamber and an effective separation effect.

[0014] Particularly preferably, the immersion tube extends over a maximum of 60% of the length of the separation chamber measured along the central axis. In particular, due to a bottom-side boundary of the expansion chamber, the light fraction of the multiphase fluid undergoes a flow reversal and is discharged from the separation chamber via the immersion tube, rotating around the central axis. If the immersion tube extends over a maximum of 60% of the length of the separation chamber measured along the central axis, the distance from the bottom-side boundary of the expansion chamber can create a particularly stable flow reversal, thereby ensuring particularly effective discharge of the first fluid phase (light fraction).

[0015] Furthermore, it is preferred that the ratio between a length of the separation chamber measured along the central axis and a largest diameter of the separation chamber is between 6:1 and 1:1. This represents the ratio range in which the most homogeneous and stable rotational flow of the fluid is achieved.

[0016] A preferred embodiment provides that the expansion space has a bottom-side fluid discharge section spaced from the central axis, which has a screw thread-like gradient relative to an orientation perpendicular to the central axis, which assists the discharge of the second fluid phase.

[0017] In particular, it is possible to operate the centrifugal separator in a configuration in which the fluid flow extends along the direction of gravity (the central axis is aligned parallel to the direction of gravity). A screw-thread-like gradient exerts a component of gravity as a downhill force toward the outlet channel on components of the heavy fraction that have reached the bottom boundary of the expansion chamber.

[0018] Furthermore, it is preferred that the outlet channel has a bottom section that, relative to an orientation perpendicular to the central axis, has an outlet channel gradient that supports the discharge of the second fluid phase, particularly in the direction of gravity. Due to the outlet channel gradient, a component of gravity acts as a downhill force on the components of the heavy fraction arranged at the bottom section, thereby supporting the discharge of the heavy fraction.

[0019] In particular, it is preferred that the expansion chamber has a bottom-side fluid guide section extending in a truncated cone or pagoda shape around the central axis. Operating conditions are possible in the expansion chamber in which a portion of the heavy fraction executes a stable rotation close to the central axis and thus does not reach the outlet channel. The truncated cone or pagoda-shaped fluid guide section forms an inclined surface around the central axis, which guides the portion of the heavy fraction radially outwards, in particular towards the outlet channel. In addition, the inclined surface serves to guide the portion of the light fraction radially inwards, thus in the direction of the central axis along which the dip tube extends.

[0020] Furthermore, it is preferred that the inlet channel has an outer boundary wall relative to the central axis, which adjoins a portion of the separation chamber wall tangentially. Due to the tangentially arranged outer boundary wall of the inlet channel, the multiphase fluid is caused to rotate along the separation chamber wall and around the central axis as soon as it is fed into the separation chamber.

[0021] According to the invention, the outlet channel has an outer boundary wall relative to the central axis, which adjoins a section of the expansion chamber wall tangentially. The tangentially arranged boundary wall of the outlet channel enables particularly efficient removal of the heavy fraction from the expansion chamber.

[0022] Furthermore, it is preferred that the inlet channel has a rectangular cross-section and / or that the outlet channel has a rectangular cross-section. The rectangular cross-section of the inlet channel allows for the ideal rotational flow of the fluid upon feeding into the separation chamber. The rectangular cross-section of the outlet channel is particularly adapted to the design of the expansion chamber.

[0023] According to the invention, an annular transition region between one end of the separation chamber wall and a boundary section covering the expansion chamber is sharp-edged or rounded. After transitioning from the separation chamber to the expansion chamber, the heavy fraction remains in the expansion chamber across the transition region and, in particular, cannot re-enter the separation chamber. The design of the annular transition region enables control of the behavior of the heavy fraction during the transition from the separation chamber to the expansion chamber and, in particular, control of the deceleration of the rotational movement.

[0024] Further features and advantages are the subject of the following description and the drawings of embodiments.

[0025] The drawing shows Fig. 1 a front view of an embodiment of a centrifugal separator; Fig. 2 a side view of the centrifugal separator according to Fig. 1 ; Fig. 3 a top view of the centrifugal separator according to Fig. 1 ; Fig. 4 a side view of the centrifugal separator along a Fig. 1 section plane marked IV - IV (central axis lies in section plane); Fig. 5 one in Fig. 4 section of a separation chamber wall marked V in an enlarged view; Fig. 6 a side view of another embodiment of a centrifugal separator; Fig. 7 a side view of another embodiment of the centrifugal separator; and Fig. 8 a side view of another embodiment of the centrifugal separator.

[0026] A centrifugal separator is designated in the drawing as a whole by the reference number 10.

[0027] The centrifugal separator 10 has a housing 12 which is essentially rotationally symmetrical with respect to a central axis 14, see Fig. 1 und Fig. 2 . The central axis 14 extends between a first end 16 of the centrifugal separator 10, at which an upper side 18 extending perpendicular to the central axis 14 is formed, and a second end 20, at which a bottom side 22 extending perpendicular to the central axis 14 is formed.

[0028] The housing 12 has a separation chamber wall 24 which, starting from the top side 18 along the central axis 14, delimits a separation chamber 26, wherein the separation chamber 26 has a length 28 measured parallel to the central axis 14. Offset from the separation chamber 26 and arranged directly adjacent along the central axis 14, the housing 12 has an expansion chamber 30. The expansion chamber 30 is delimited by an expansion chamber wall 32 of the housing 12 and by the bottom side 22 of the second end 20.

[0029] The separation chamber 26 is designed to widen conically from the first end 18 in the direction of the expansion chamber 30, i.e., a diameter of the separation chamber 26 measured perpendicular to the central axis 14 increases in the direction of the expansion chamber 30 until a largest diameter 34 of the separation chamber 26 is reached. The conical widening of the separation chamber 26 is accompanied by a (negative) angle of inclination 36 of the separation chamber wall 24 relative to the central axis 14.

[0030] The separation chamber 26 opens at an annular transition region 38 to an annular disk-shaped boundary section 40 covering the expansion chamber 26. The transition region 38 can be sharp-edged or rounded.

[0031] The expansion chamber 30 has a diameter 42 measured perpendicular to the central axis 14. The diameter 42 of the expansion chamber 30 is larger than the largest diameter 34 of the separation chamber 26.

[0032] The separation chamber 26 is connected near the top 18 to an inlet channel 44 (compare Fig. 3 und 4 ). The inlet channel 44 preferably has a rectangular cross-section. An outer boundary wall 46 of the inlet channel 44, relative to the central axis 14, is formed in particular tangentially adjacent to a section 48 of the separation chamber wall 24, see Fig. 3 .

[0033] A dip tube 50 is arranged on the top side 18 of the housing 12. The dip tube 50 extends along the central axis 14 into the separation chamber 26, see Fig. 4 . A length 52 of the dip tube 50 taken up by the separation chamber 26 is measured parallel to the central axis 14.

[0034] The expansion chamber 30 is connected to an outlet channel 54, wherein the outlet channel 54 preferably has a rectangular cross-section. An outer boundary wall 56 of the outlet channel 54, relative to the central axis 14, is formed tangentially adjacent to a section 58 of the expansion chamber wall 32, see Fig. 3 .

[0035] During operation of the centrifugal separator 10, a multiphase fluid is fed into the separation chamber 26 via the inlet channel 44, wherein the multiphase fluid is composed in particular of fluid phases of different densities (light fraction and heavy fraction).

[0036] In the separation chamber 26, the multiphase fluid is guided along an inner side 60 of the separation chamber wall 24, whereby a flow is formed which extends spirally around the central axis 14 and has a flow component which points in the direction of the expansion chamber 30.

[0037] The flow-induced centrifugal forces cause a radially outward acceleration, in particular of the heavy fraction, and the separation of the heavy fraction on the inner side 60 of the separation chamber wall 24.

[0038] The light fraction undergoes a flow reversal near the bottom side 22 and moves along the central axis 14 in the direction of the dip tube 50. The light fraction is discharged from the separation chamber 26 via the dip tube 50.

[0039] A radially outwardly directed centrifugal force 64 continues to act on the components 62 of the heavy fraction arranged on the inner side 60 of the separation chamber wall 24, compare Fig. 5 The centrifugal force 64 has a first component 66 and a second component 68. The first component 66 acts as a normal force on the components 62 of the heavy fraction and is oriented perpendicular to the inner side 60 of the separation chamber wall 24.

[0040] The second component 68 of the centrifugal force 64 is aligned parallel to the inner side 60 of the separation chamber wall 24. Due to the conical expansion of the separation chamber 26 along the central axis 14, the second component 68 of the centrifugal force 64 is directed toward the expansion chamber 30. This causes an acceleration of the components 62 of the heavy fraction toward the expansion chamber 30 and an increased removal rate from the separation chamber 26 into the expansion chamber 30.

[0041] The magnitude of the second component 68 of the centrifugal force 64 depends on the magnitude of the inclination angle 36. A larger inclination angle 36 measured relative to the central axis 14 is accompanied by a larger magnitude of the second component 68 of the centrifugal force 64.

[0042] If the components 62 of the heavy fraction are taken up in the expansion chamber 30, the rotation speed of the heavy fraction slows down due to the enlarged diameter 42 of the expansion chamber 30, and the heavy fraction is discharged from the expansion chamber 30 via the outlet channel 54, compare e.g. Fig. 1 .

[0043] Operating states of the centrifugal separator 10 are conceivable during which components 62 of the heavy fraction accumulate on the bottom side 18. This may impair the removal of the components 62 of the heavy fraction from the expansion chamber 30.

[0044] In order to improve the removal of the heavy fraction from the expansion chamber 30, in a further embodiment of the centrifugal separator 10, a bottom-side first fluid removal section 70 is provided, which is spaced apart from the central axis 14 and has a screw thread-like gradient 72 relative to an orientation perpendicular to the central axis 14, see Fig. 6 .

[0045] An improvement in the removal of the heavy fraction can also be achieved with a bottom section 74 of the outlet channel 54, wherein the bottom section 74 has an outlet channel gradient 76 with respect to an orientation perpendicular to the central axis 14.

[0046] Operating conditions are also conceivable during which a portion of the heavy fraction in the expansion chamber 30 and / or the separation chamber 26 performs a stable rotation near the central axis 14 and thus does not reach the outlet channel 54. To avoid such operating conditions, bottom-side fluid guide sections are provided in further embodiments of the centrifugal separator 10.

[0047] For example, a truncated cone-shaped fluid guide section 78 is provided, compare Fig. 7 , or a pagoda-shaped fluid guide section 80, compare Fig. 8 The fluid guide sections 78, 80 extend annularly around the respective central axis 14. The upper sides of the fluid guide sections 78, 80 facing the separation chamber 26 or the expansion chamber 30 form inclined guide surfaces for guiding the components 62 of the heavy fraction radially outward, in particular in the direction of the outlet channel 54.

Claims

1. Centrifugal separator (10), comprising a housing (12) extending along a central axis (14), which has a separation chamber wall (24) for delimiting a separation chamber (26) which is fed by an inlet channel (44) for multi-phase fluid, wherein a central immersion tube (50) is provided for discharging a first fluid phase and an outlet channel (54) is provided for discharging a second fluid phase, wherein the separation chamber (26) widens conically from the inlet channel (44) along the central axis (14) in the direction of the expansion chamber (30), wherein an expansion chamber (30) is provided between the separation chamber (26) and the outlet channel (54), which expansion chamber widens radially outwards with respect to the separation chamber (26) and is delimited radially outwards by an expansion chamber wall (32), wherein a diameter (42) of the expansion chamber (30) measured perpendicularly to the central axis (14) is larger than a largest diameter (34) of the separation chamber (26) measured perpendicularly to the central axis (14), wherein the separation chamber (26) opens at an annular transition region (38) into an annular-disk-shaped boundary portion (40) covering the expansion chamber (26), wherein the annular transition region (38) between an end (40) of the separation chamber wall (26) and the boundary portion (40) covering the expansion chamber (30) is sharp-edged or rounded, and wherein the outlet channel (54) has an outer boundary wall (56) with respect to the central axis (14), which tangentially adjoins a portion (58) of the expansion chamber wall (32).

2. Centrifugal separator (10) according to claim 1, characterized in that an angle of inclination (36) of the separation chamber wall (24), measured relative to the central axis (14), is between 2° and 20°, in particular between 2.5° and 15°.

3. Centrifugal separator (10) according to either of the preceding claims, characterized in that the immersion tube (50) extends over a maximum of 60% of a length (28) of the separation chamber (26) measured along the central axis (14).

4. Centrifugal separator (10) according to any of the preceding claims, characterized in that the ratio between the length (28) of the separation chamber (26) measured along the central axis (14) and the largest diameter (34) of the separation chamber (26) is between 6:1 and 1:1.

5. Centrifugal separator (10) according to any of the preceding claims, characterized in that the expansion chamber (30) has a bottom-side fluid discharge portion (70) which is spaced apart from the central axis (14) and which, with respect to an orientation perpendicular to the central axis (14), has a screwthread-like slope (72) which assists with the discharge of the second fluid phase.

6. Centrifugal separator (10) according to any of the preceding claims, characterized in that the outlet channel (54) has a bottom portion (74) which, with respect to an orientation perpendicular to the central axis (14), has an outlet channel slope (76) which assists with the discharge of the second fluid phase.

7. Centrifugal separator (10) according to any of the preceding claims, characterized in that the expansion chamber (30) has a bottom-side fluid guide portion (78) extending in the manner of truncated cone or pagoda around the central axis (14).

8. Centrifugal separator (10) according to any of the preceding claims, characterized in that the inlet channel (44) has an outer boundary wall (46) with respect to the central axis (14), which tangentially adjoins a portion (48) of the separation chamber wall (24).

9. Centrifugal separator (10) according to any of the preceding claims, characterized in that the inlet channel (44) is rectangular in cross-section and / or in that the outlet channel (54) is rectangular in cross-section.