NL2010608C2 - Separator device, treatment plant and method for separating a three-phase fluid. - Google Patents

Description

Separator device, treatment plant and method for separating a three-phase fluid

The present invention relates to a separator device for a three-phase fluid containing liquid, gas and solid particles. Such separator device is also referred to as a purifier and is used for aerobic or anaerobic purification of waste water, for example. Such waste waters comprise a fluid that contains water, gas and dissolved and non-dissolved solid parts involving organic and/or inorganic material. The gas may contain air, oxygen and gases that are produced in waste water treatments such as methane and carbon dioxide.

Conventional three-phase separators comprise a first separator separating the gas from the fluid. After the first separator there is provided a settler for separating solid particles from the remaining two-phase mixture. A second separator separates the remaining solid particles from this two-phase mixture. Therefore, these conventional separators involve a first separator for separation of gases from the three-phase fluid, while solid particles are separated from the remaining two-phase mixture through discharging from the settler and separation in the second separator. This leads to a relatively inefficient separation process .

The present invention has for its object to provide a separator device obviating or at least reducing the aforementioned problems.

This objective is achieved with a separator device according to the invention for a three-phase fluid containing liquid, gas and solid particles, the separator device comprising: an inlet configured for receiving the fluid; a tubular separator that is connected to the inlet, the tubular separator comprising: - a number of tubes that are placed with their longitudinal axis at an angle relative to the vertical such that the flow through the tubes is caused to flow obliquely along the tube, thereby accumulating gas at or near the top of a vertical cross-section of the tube such that a degasification is achieved, and accumulating solid parts at or near the bottom of the vertical cross-section of the tubes such that in use a pre-separation of the solid parts is achieved; and - an outlet for the liquid and pre-separated solid particles with the outlet being connected to a solid collection chamber.

By providing the tubular separator that is connected to the inlet of the separator device a separating step for a three-phase fluid can be performed. By providing a number of tubes in the tubular separator and placing each individual tube with the longitudinal axis, in other words their centreline, at an angle relative to the vertical the flow through the tubes is caused to flow obliquely along the tube. In such configuration, gas accumulates at or near the top or upper part of the vertical cross-section of the tube. This achieves a degasification of the three-phase fluid. The gases that are separated from the incoming three-phase fluid will be provided to a gas outlet. In a presently preferred embodiment this gas outlet is formed by the fluid inlet of the separator device. Alternatively, a separate gas outlet can be provided. By accumulating gas at the top of the cross-section of the tube a sort of gas channel inside the tube is achieved. This enables an effective removal of the separated gas from the remaining fluid flow.

In addition to the gas accumulation at or near the top of the vertical cross-section of the tube, providing tubes at an angle achieves that in use a pre-separation of the solid parts at or near the bottom of the vertical cross-section of the tube takes place. By performing a preseparation of the solid parts in the separator device according to the present invention the overall solid separation is significantly improved. Such solid separation is one of the decisive factors in performing an efficient and effective separation.

Preferably, the angle between the longitudinal axis of a tube with the vertical is in the range of 0-80°, preferably in the range of 10-70°, more preferably in the range of 25-60° and, most preferably, the angle is about 35°. The inclination of the tubes in the separator device according to the present invention decreases the effective settling distance for the solid particles and, in addition, decreases the effective rising distance for gas as compared to a non-inclined settler. Therefore, the inclination according to the present invention improves the separation efficiency.

In a presently preferred embodiment according to the invention the cross-section of the tubes has a circular or an ellipse shape.

By providing the tubes with a circular or ellipse shape it was shown that gas removal or degasification is performed more effectively as compared to a tube that is provided with a rectangular shape, for example. This is caused by the accumulation of the gas at a specific location or region at the top of the cross-section. It is noted that other shapes according to the invention would also be possible, although it turns out to be beneficial to have a shape that accumulates the gas at a specific region at or near the top of the cross-section. This involves the aforementioned circular or ellipse-shaped tubes. Although a curved circumference is preferred, alternatively, or in addition thereto, also rectangular or other shapes could be used, preferably with one of the corners oriented upwards, or in other words in a configuration similar to a diamonds configuration in cards.

Accumulating gas at or near the top of any cross-section of the tube, including any vertical sectional view of the tube, a higher upwards oriented force in the gas is achieved thereby increasing the rising capacity of the gas. In addition, a counter-flow will be generated at or near the top of the upper part of the cross-section of the tube thereby affecting the total flow velocity profile within the tube. In fact, in the tubes of the separator device according to the present invention the highest velocity will be below the centreline of the tube thereby providing a sort of sweeping effect within the tube. This surprising effect brings about the joint separation of small solid particles and gas in the upward direction. With conventional separators gas that is attached to small solid particles often prevents the small solid particles from settling thereby preventing or at least hindering degasification of the three-phase fluid such that these particles with the attached gas will flow through the settler and flush out. Surprisingly, due to the sweeping effect in the tube provided in the separator device according to the present invention the small solid particles with attached gas will be fed back to the top or upper part of the tube such that the degassing can restart for these particles.

As a further effect of this counter-flow the solid particles are separated more efficiently, as the downward velocity in the tube is increased. In fact, the solid particles gain settling capacity such that the solid particles are accumulated more effectively at or near the bottom of the lower part of the tube. This further improves the pre-separation of the solid particles in the separator device according to the present invention with the tubular separator. In fact in this pre-separation a substantial part of the solid particles will be removed. In use, the remaining two-phase flow after the tubular separator, which is degassed and wherein most solid particles have been preseparated, may enter a solid collection chamber and a second separator for further removal of the remaining solid particles in the two-phase fluid.

In a presently preferred embodiment according to the present invention the number of tubes in a separator is in a range of 5-200, preferably in the range of 10-100, and most preferably in the range of 10-80.

It has been found that providing the tubular separator with a number of tubes especially in the range of 10-80 has proven to provide a cost-effective and relatively very efficient separation enabling a degasification and a pre-separation of solid particles from a three-phase fluid. It will be understood that the exact number of tubes may also depend on the treatment plant wherein the separator device according to the present invention would be implemented.

Preferably, the tubes have an inner diameter in the range of 50-1000 mm, more preferably in the range of 100-500 mm and most preferably in the range of 120-250 mm.

It was shown that inner diameters especially in the range of 120-250 mm, such as 150 mm, provide optimal results enabling a thorough degasification and pre-separation of the three-phase fluid.

In a presently preferred embodiment the inlet of the separation device according to the present invention comprises a cover.

Providing a cover achieves that any inter-tubular spaces are covered such that the fluid has no other choice than to enter the inside of any of the tubes to flow through the separator device according to the present invention.

This improves the overall degasification and pre-separation of solid particles.

In a presently preferred embodiment according to the present invention the separator device further comprises a solid collection chamber and a second separator for separating the two-phase mixture of liquid and remaining solid particles.

Due to the pre-separation of solid particles in the tubular separator the solid particles are separated effectively. Due to the increased settling capacity of the solid particles a substantial, in fact almost all, solid particles will be removed in the first separator.

Preferably, the solid particles are being collected in a cone-shaped collection chamber and forced through the solid outlet due to the different specific mass of the solid particles. The remaining two-phase fluid preferably enters the second separator from below such that the flow direction through the second separator would be upwards. In case one applies a plate-shaped laminar separator the remaining solid particles can be separated from the liquid.

As an additional advantage, due to the preseparation of solid particles from the three-phase flow in the tubular separator of the separator device according to the present invention, the configuration of the second separator can be brought into conformity with the new separator device. This enables a significant cost-reduction for the second separator. Ultimately, due to the preseparation of the solid particles, possibly depending on the target set for the solid particle content of the purified liquid, the second separator need not to be provided at all. Obviously, the actual configuration of the second separator strongly depends on the specific application and/or specific dimensions of the entire process.

The invention further relates to a treatment plant comprising a separator device as described above.

Such treatment plant provides the same effects and advantages as those stated with reference to the separator device. The treatment plant may comprise one or more separator devices. The treatment plant may involve waste water treatment involving aerobic and/or anaerobic purification of such waste water.

The invention further also relates to a method for separating a three-phase fluid containing liquid, gas and solid particles, the method comprising the steps of: providing a separator device as described above; supplying the flow by the inlet to the tubes; accumulating gas at or near the top of the vertical cross-section of the tubes thereby performing a separation of a substantial part of the gas from the fluid; accumulating solid particles at or near the bottom of the vertical cross-section of the tubes thereby performing a pre-separation of a substantial part of the solid particles from the fluid; and providing the flow to an outlet.

Such method provides the same effects and advantages as those stated with reference to the separator device and/or treatment plant.

Preferably, in the method according to the present invention the flow is directed in a substantially downward direction and/or achieves a substantially laminar flow in the tube configuration. Preferably, a counter-flow is provided at or near the top of a cross-section of the tube. As mentioned earlier, for the separator device according to the present invention, this significantly improves the separation and more specifically the pre-separation of the solid particles from the fluid. More particularly, the counter-flow produces the highest average flow velocity between the centreline of the tube and the bottom of the cross-section of the tube. By providing the highest average flow velocity not along the centre axis of the tube, but more towards the bottom of the tube when seen in a vertical cross-section thereof, the settling capacity of the solid particles is improved.

Furthermore, in a presently preferred embodiment the method according to the invention comprises the additional step of separating the solid particles from the flow at the solid collection chamber before separating the remaining solid particles from the flow in a second separator. This improves the overall efficiency of the separation process for the three-phase fluid.

Further advantages, features and details of the invention are elucidated on the basis of preferred embodiments thereof, wherein reference is made to the accompanying drawings, in which:

Figure 1 shows an overview of a separator comprising a separator device according to the present invention; Figure 2 shows a view of the separator of figure 1 from above;

Figure 3 shows the flow inside the tube of a separator device according to the invention;

Figures 4A and B show side views of the separator of figure 1; and

Figure 5 shows the method steps according to the invention.

Separator 2 (figure 1) comprises separator device 4, solid collection chamber 6 and second separator 8. Separator device 4 comprises a number of tubes 10 that are provided at an angle a with the vertical. In the illustrated embodiment two rows of nineteen tubes 10 have been provided on both sides of second separator 8. In the illustrated embodiment separator 2 comprises inlet section 12 with inlets 14 to the individual tubes 10. In addition, inlet section 12 comprises cover plate 16 covering the intermediate or inter-tubular spaces 18 between individual tubes 10.

By a downward flow in direction A the fluid enters collection chamber 6 that is provided with a solid outlet 20 and in the illustrated embodiment with an additional connection 22. From collection chamber 20 the remaining flow flows upwards between plates 24 of second separator 8 and leaves the separator 2 through outlet 26. In the illustrated embodiment an additional connection 28 is provided for second separator 8.

In the illustrated embodiment in total thirty-six tubes 10 (figure 2) are provided for separator device 4.

Flow 30 (figure 3) entering tube 10 at tube inlet 14 flows in a substantially downward direction A. In the illustrated embodiment tube 10 is put at an angle a with the vertical 32 of about 35°. The three-phase flow 30 comprises a liquid 34, gas 36 and solid particles 38. Gas 36 accumulates at the or near the top 40 of a vertical cross section 42 while solid particles 38 accumulate at or near bottom part 44 of vertical cross-section 42 such that solid particles move in downward settling direction 46. The accumulated gas 36 leaves tube 10 at gas outlet 48. In the illustrated embodiment gas outlet 38 corresponds with the tube inlet 14. It will be understood that other configurations with a separate gas outlet 48 would also be possible. Due to the specific configuration of tubes 10 of tubular separator 4, in use, a counter-flow 50 will be produced in tube 10 thereby improving removal of gas 36 and increasing settler capacity of solid particles 38. Gas 36 is separated from the three-phase flow 30 and exits at tube outlet 52. The substantially two-phase mixture of liquid 34 and pre-separated solid particles 38 leaves tube 10. The pre-separated solid particles 38 can be separated relatively easy from the two-phase flow from outlet 52.

In the illustrated embodiment collection chamber 6 is provided with four solid outlets 20 (figures 4A and B).

It will be understood that the number of outlets 20 depends on the specific configuration of separator 2. In the illustrated embodiment the total height of separator 2 is between 2500 and 3000 mm, while the length of separator 2 is about 6000 mm. It will be understood that other dimensions of separator 2 and its part according to the invention would also be possible.

Purification method (figure 5) starts with supply step 56 providing a three-phase flow 30 to separator device 4. In flow step 58 from tube inlet 14 the flow 30 is fed into tube 10 where in accumulation step 60 gas 36 is accumulated and solid particles 38 are accumulated. In gas removal step 62 gas is removed to gas outlet 48. In two-phase removal step 64 the mixture is provided to collection chamber 6 from which the solid particles 38 are removed in solid removal step 66 while the remaining flow of liquid 34 with the remaining solid particles 38 are provided in step 68 to second separator 8. In step 70, purifying liquid is removed from separator 2, with any remaining solid particles will be removed from second separator 8 in sep 72.

It will be understood that different configurations and/or different dimensions of separator 2 would be possible depending on the specific conditions wherein separator 2 is being applied. For example, in case the pre-separation of solid particles 38 would suffice, the second separator 8 can be omitted from separator 2.

The present invention is by no means limited to the above described preferred embodiments thereof. The rights sought are defined by the following claims within the scope of which many modifications can be envisaged.

Clauses 1. Separator device for a three-phased fluid containing liquid, gas and solid particles, the device comprising: an inlet configured for receiving the fluid; a tubular separator that is connected to the inlet, the tubular separator comprising: - a number of tubes that are placed with their longitudinal axis at an angle relative to the vertical such that the flow through the tubes is caused to flow obliquely along the tube, thereby accumulating gas at or near the top of a vertical cross-section of the tubes such that a degasification is achieved, and accumulating solid parts at or near the bottom of the vertical cross-section of the tubes such that in use a pre-separation of the solid parts is achieved; and - an outlet for the liquid and pre-separated solid particles with the outlet being connected to a solid collection chamber.

2. Separator device according to clause 1, wherein the angle is in the range of 0°-80°, preferably in the range of 10°-70°, more preferably in the range of 25°-60°, and most preferably about 35°.

3. Separator device according to clause 1 or 2, wherein the cross-section of the tubes has a circular or ellipse shape.

4. Separator device according to clause 1, 2 or 3, wherein the number of tubes is in the range of 5-200, preferably in the range of 10-100, and most preferably in the range of 10-80.

5. Separator device according to clause 4, wherein the tubes have a diameter in the range of 50-1000 mm, preferably in the range of 100-500 mm, and most preferably in the range of 120-250 mm.

6. Separator device according to clause 3, 4 or 5, wherein the inlet comprises a cover to force the fluid through the tubes and prevents the incoming fluid entering any inter-tubular space.

7. Separator device according to one or more of the foregoing clauses, further comprising a solid collection chamber and a second separator for separating the two-phase mixture of liquid and remaining solid particles.

8. Treatment plant comprising a separator device according to one or more of the foregoing clauses.

9. Method for separating a three-phase fluid containing liquid, gas and solid particles, comprising the steps of: providing a separator device according to one or more of the foregoing clauses 1-7; supplying the flow by the inlet to the tubes; accumulating gas at or near the top of the vertical cross-section of the tubes thereby performing a separation of a substantial part of the gas from the fluid; accumulating solid particles at or near the bottom of the vertical cross-section of the tubes thereby performing a pre-separation of a substantial part of the solid particles from the fluid; and providing the flow to an outlet.

10. Method according to clause 9, wherein the flow is directed in a substantially downward direction.

11. Method according to clause 9 or 10, wherein the tubes are configured to achieve a substantially laminar flow.

12. Method according to clause 9, 10 or 11, further comprising the step of providing a counter-flow at or near the top of a cross-section of the tube.

13. Method according to clause 12, wherein the counter-flow produces the highest average flow velocity at or near the bottom of the cross-section of the tube, 14. Method according to one or more of the clauses 9-13, further comprising the steps of separating the solid particles from the flow at a solid collection chamber and separating the remaining solid particles from the flow in a second separator.

Claims (14)

A separation device for a three-phase fluid-containing liquid, gas and solid particles, the device comprising: an inlet configured to receive the fluid; a tubular separator connected to the inlet, the tubular separator comprising: a plurality of tubes which are angled with a longitudinal axis to the vertical such that the flow through the tubes flows through the tube at an angle, thereby accumulating gas in or near the upper end of a vertical cross-section of the tubes such that a degassing is effected, and solid particles accumulating in or near the bottom of the vertical cross-section of the tubes such that in use a pre-separation of the solid particles is effected; and an outlet for the liquid and pre-separated solid particles wherein the outlet is connected to a solid collecting chamber. The separator of claim 1, wherein the angle is in the range of 0-80 °, preferably in the range of 10-70 °, more preferably in the range of 25-60 °, and most preferably about 35 °. 3. Separating device as claimed in claim 1 or 2, wherein the cross-section of the tubes is a circular or elliptical. Separator according to claim 1, 2 or 3, wherein the number of tubes is in the range of 5-200, preferably in the range of 10-100, and most preferably in the range of 10-80. The separator of claim 4, wherein the tubes have a diameter in the range of 50-1000 mm, preferably in the range of 100-500 mm, and most preferably in the range of 120-250 mm. A separation device according to claim 3, 4 or 5, wherein the inlet comprises a cover for forcing the fluid through the tube and preventing the incoming fluid from entering an inter-tube space. The separation device according to one or more of the preceding claims, further comprising a solid collecting chamber and a second separator for separating the two phase mixture of liquid and remaining solid particles. 8. Treatment installation comprising a separation device according to one or more of the preceding claims. A method for separating a three-phase fluid-containing liquid, gas, and solid particles, comprising the steps of: providing a separation device according to one or more of the preceding claims 1-7; providing the fluid through the inlet to the tubes; accumulating gas in or at the top of the vertical cross-section of the tubes thereby performing a separation of a substantial portion of the gas from the fluid; accumulating solid particles in or at the bottom of the vertical cross-section of the tubes thereby performing a pre-separation of a substantial portion of the solid particles from the fluid; and providing the power to an outlet. The method of claim 9, wherein the stream is directed in a substantially downward direction. The method of claim 9 or 10, wherein the tubes are configured to effect a substantially laminar flow. The method of claim 9, 10 or 11, further comprising the step of providing a counter-current in or near the top of a cross-section of the tube. The method of claim 12, wherein the countercurrent produces the highest average flow rate in or near the bottom of the cross-section of the tube. The method of any one of claims 9-13, further comprising the steps of separating the solid particles from the stream in a solid collecting chamber and separating the remaining solid particles from the stream in a second separator.