DE102015119165A1 - Process for clarifying a flowable product with a centrifuge, in particular a separator - Google Patents

Abstract

Process for clarifying a flowable starting product (AP) with a centrifuge, in particular a separator with a rotatable drum (1) with an inlet (4) and at least one liquid outlet (13) for the continuous discharge of at least one clarified liquid phase - a clear phase - and discontinuous openable solids outlet openings (5) for the discontinuous discharge of a solid phase - called solids discharge, characterized by at least the following steps: 100: setting or determining a time interval which is limited by a start time (t1) and an end time (t2), wherein in the time interval a next solids discharge after a previous solids discharge should take place; 200: performing a centrifugal clarification of the starting product (AP) in the drum (1); 300: repeatedly determining at least one actual value of a parameter, in particular of a product or method parameter, during step 200; 400: carrying out a solids discharge when the parameter deviates from a limit value, in particular exceeds a limit value; and 500, 900: determining the time (tE) of the actual solids discharge and checking to see if it is in the time interval from step 100; and returning to step 200 if the instant (tE) of the actual solids discharge is in the time interval of step 100; or performing a change in a discharge volume for the next solids discharge and / or a product feed volume per unit time, if the time (tE) of the current solids discharge is not in the time interval from the step 100.

Description

The invention relates to a method according to the preamble of claim 1.

The clarification of a self-emptying separator for clarifying a processed product of solids is among other things by parameters such as the clarification surface of the plate package, the size of the solids space in the drum, the design of the centripetal pump for discharging the clear phase, the drive power of the engine and the set feed volume per Time unit (inflow) and limits the amount of solids contained in the product. In many self-cleaning separators the solids discharge is triggered after a fixed time interval. The time between emptying (emptying frequency) depends on the above mentioned parameters. If more volume is emptied during solid discharge than there is solid in the drum, this usually leads to product loss.

To prevent this, in modern centrifuges not only is emptied per period of time, but also the solids discharge by a sensor device ( DE 32 28 074 A1 ) triggered, z. B. by a turbidity measurement of the Klarphasenablaufs or comparable systems. Since the emptying volume is also set constant here, an increase in the solids content in the feed (for example starting product from a tank bottom cone) can lead to a significant increase in the emptying frequency, which should be avoided.

Against this background, the invention has the object of further developing the generic method in such a way that overall good control of the evacuations and thus of the entire clarification process is possible with it.

The invention solves this problem by the subject matter of claim 1.

Advantageous embodiments of the method according to the invention can be found in the subclaims.

• 100: Setzen oder Bestimmen eines Zeitintervalls, das durch einen Startzeitpunkt und einen Endzeitpunkt begrenzt ist und in dem eine nächste Feststoffentleerung nach einer vorhergehenden Feststoffentleerung erfolgen soll;
• 200: Durchführen eines zentrifugalen Klärens des Ausgangsproduktes in der Trommel;
• 300: wiederholtes Bestimmen wenigstens eines Istwertes eines Parameters, insbesondere eines Produkt- oder Verfahrensparameters, insbesondere eines Produktparameters der aus der Trommel abgeleiteten Klarphase, während des Schrittes 200;
• 400: Durchführen einer Feststoffentleerung, wenn der Parameter von einem Grenzwert abweicht, insbesondere einen Grenzwert überschreitet; und
• 500, 900: Bestimmen des Zeitpunkts (t_E) der aktuellen Feststoffentleerung und prüfen, ob dieser in dem Zeitintervall aus dem Schritt 100 liegt; und
• – Rückkehr zu Schritt 200, wenn der Zeitpunkt t_E der aktuellen Feststoffentleerung in dem Zeitintervall aus Schritt 100 liegt;
• – oder Durchführung einer Veränderung eines Entleerungsvolumens für die nächste Feststoffentleerung und/oder eines Produktzulaufvolumens pro Zeiteinheit, wenn der Zeitpunkt t_E der aktuellen Feststoffentleerung nicht in dem Zeitintervall aus dem Schritt 100 liegt.

Claim 1 provides a method for clarifying a flowable starting product with a centrifuge, in particular a separator with a rotatable drum with an inlet and at least one liquid outlet for the continuous outlet of at least one clarified liquid phase - a clear phase - and with discontinuously opening solids outlet for discontinuous discharge of the solid phase - called solids discharge -, with at least the following steps:

• 100 : Setting or determining a time interval which is limited by a start time and an end time and in which a next solids discharge is to take place after a previous solids discharge;
• 200 : Performing a centrifugal clarification of the starting product in the drum;
• 300 in that the repeated determination of at least one actual value of a parameter, in particular of a product or process parameter, in particular of a product parameter of the clear phase derived from the drum, during the step 200 ;
• 400 Carrying out a solids discharge when the parameter deviates from a limit value, in particular exceeds a limit value; and
• 500 . 900 Determining the time (t _E ) of the current solids discharge and check whether this in the time interval from the step 100 lies; and
• - return to step 200 when the instant t _{E of} the actual solids discharge in the time interval from step 100 lies;
• - or carrying out a change in a discharge volume for the next solids discharge and / or a product feed volume per unit time, if the time t _{E of} the current solids discharge not in the time interval from the step 100 lies.

Preferably, in step 100 further defines and / or sets:
a maximum limit value for the parameter which can not be exceeded; the volume of starting material flowing into the drum and to be clarified there per unit time; and / or the volume of solids to be emptied at the next solids discharge to a value which is less than a maximum value and greater than a minimum value.

It has proved in practice to be useful and advantageous for a safe and stable operation of the method, if the time interval is within the following range: 0 sec ≤ t ₂ - t ₁ ≤ 300 sec. Thus, the starting point and the end time can be the same be such that the time interval is zero, or otherwise, the time interval within which the emptying should follow can be up to 5 minutes before any adjustment of parameters to arrive at the next emptying as possible within the time interval. In the first case, there is always an adjustment of the parameters after each emptying. The longer the interval becomes, the less frequently parameter adjustments are necessary.

It is preferably when in step 500 it is determined that the last solids discharge E of the step 400 was triggered before reaching the start time t _{1 of} the time interval, in one step 700 the emptying volume V _E for increases the next solids discharge or the product feed volume P _Z per unit time in one step 800 reduced. If it is determined after prolonged operation that the predetermined time interval has not been selected optimally, this can also be changed, for example manually by an input or automatically by a calculation, and the method can be restarted virtually.

It is further preferably, if in step 900 it is determined that the last solids discharge E of the step 400 was triggered after reaching the end time t _{2 of} the time interval, the emptying volume V _E for the next solids discharge in one step 1100 decreases or the product feed volume per unit of time in one step 1200 elevated.

The subject matter of claim 1 and the subject matters of the subclaims ensure in each case in a simple manner that even when the solids content in the feed of the centrifuge fluctuates greatly, the solids discharge is carried out in a well-controlled manner.

Deviating from a parameter limit may also be a departure from a derivative limit (limit for a gradient) in determining a temporal behavior of the parameter. In addition, one or more parameters can be determined. Possibly. the emptying is triggered when one of the parameters first exceeds a set limit (eg turbidity level and viscosity).

In particular, the emptying frequency, the emptying volume and the amount of inflowing product per unit time are adjusted in a simple manner such that required quality properties (eg selectivity and dry substance) of the centrifugal separation are reproducibly maintained.

The invention will be explained in more detail below with reference to a preferred embodiment with reference to the accompanying drawings. It shows:

1 FIG. 2: schematic sectional view of a separator operated by the method according to the invention; FIG.

2 : an exemplary diagram for illustrating the method according to the invention;

3 a flowchart of an embodiment of a method according to the invention.

1 shows a separator for clarifying turbid-containing, flowable starting products AP with a rotatable drum 1 with vertical axis of rotation. The processing of the product takes place in continuous operation. This means that the product feed takes place continuously and also the derivation of at least one clarified liquid phase, called the clear phase, takes place continuously. The drum 1 In the embodiment as a self-emptying centrifuge, the separator has a discontinuous solids outlet, the solid F separated off from the starting product AP being clarified by the opening and reclosing of outlet nozzles or outlet openings 5 Will get removed.

The drum 1 has a drum base 10 and a drum lid 11 on. It is also preferably of a hood 12 surround. The drum 1 is also on a drive spindle 2 attached, which is rotatably mounted and motor driven.

The drum 1 indicates a product feed 4 on, through which a starting product AP in the drum 1 is directed. It also has at least one sequence 13 with a gripper, which for the derivation of a clear phase KP from the drum 1 serves. The gripper is a kind of centripetal pump. The liquid outlet could also be done by other means. In addition, it would also be conceivable, in addition to the clarification, to carry out a separation of the product into two liquid phases of different densities. For this purpose, a further liquid flow would be required.

The drum 1 preferably has a plate package 14 from axially spaced separation plates. Between the outer circumference of the plate package 14 and the inner circumference of the drum 1 in the region of its largest inner diameter is a solids collecting space 8th educated. Solids, which are in the area of the plate package 14 be separated from the clear phase, accumulate in the solids collection room 8th from which the solids pass through the outlet nozzles 5 from the drum 1 can be discharged. The outlet nozzles 5 can by means of a piston valve 6 , which in the drum base 10 is arranged, opened and closed. When the outlet nozzles are open, the solid F is removed from the drum 1 into a solids catcher 7 directed.

To move the spool, the drum 1 an actuating mechanism. Here this comprises at least one supply line 15 for a control fluid such as water and a valve assembly 16 in the drum 1 and other elements outside the drum. Thus, the feed of the control fluid is like water over an outside of the drum 1 arranged metering arrangement 17 allows which one outside the drum 1 arranged feed line 19 is assigned for the control fluid, so that for a solids discharge by releasing the control valve, the control fluid into the drum 1 injectable or vice versa, the flow of control fluid can be interrupted to move the spool valve to release the outlet ports.

On or in the process 13 the clear phase KP is at least one sensor device 22 arranged to determine one or more parameters of the at least one clear phase KP. Parameters in the context of the present invention are, in particular, physical properties of the measuring medium "clear phase" KP, such as the degree of turbidity, the viscosity or else the conductivity (for example in the case of salt solutions). The at least one sensor device 22 can z. B. be designed as a photocell for determining the light transmittance for determining the degree of turbidity TR. In a design which additionally separates the clarified liquid clear phase into two different dense liquid phases, the degree of turbidity in one or both of the two liquid phases can be measured. The degree of turbidity is defined, for example, starting from a maximum permissible value: TR _M : = 100%.

On or in the inflow 4 for the starting product AP in the drum 1 can - but does not have to - also a sensor device 3 for determining the flow rate or one or more parameters of the into the drum 1 be arranged to conductive starting product. These parameters can also be physical parameters such as the degree of turbidity or the viscosity of the starting product.

Such determinations can be carried out, for example, by means of suitable sensors as transmission measurements or scattered light measurements. Another way to determine the degree of turbidity are ultrasonic measurements. In contrast, process parameters such as volume flow, mass flow or flow rate are known and measurable.

In a preferred embodiment variant, the sensor device can each be integrated into a measuring device which has a clear-phase or initial product parameter-that is to say, for example, B. the degree of turbidity TR or the conductivity - and at the same time determines a process parameter - such. As the volume per unit time of the clear phase - determined.

As already mentioned, analogously to the determination of one or more product parameters of the clear phase KP in a particularly preferred variant, a determination of one or more product parameters (n) - for example by means of a turbidity measurement and / or a viscosity measurement of the starting product AP at the product feed 4 - respectively.

The sensors 3 and 22 are about data connections 20 . 21 with the evaluation and control unit 9 (Preferably, a control computer of the separator) connected, which evaluates the measured values determined and the movement of the piston valve 6 and thus also the time interval until the opening of the outlet nozzles 5 controls.

The actuating mechanism for the spool 6 - Here in particular the metering 17 - is via a data connection 18 with a control unit 9 connected to the control and / or regulation of the solids outlet. The dosing arrangement 17 For example, it may have a piston and one or more valves. You can also by type of DE 10 2005 049 941 A1 be configured to make a variable dosage of the amount of fluid to control and change the duration of the solids discharge and thus the current emptying volume V _E. With the dosing arrangement 17 can be the emptying volume vary, so that, for example, with increasing solids content in the inlet, the emptying volume can be increased.

It is also another controllable device 23 - For example, a controllable valve - in the inlet 4 connected, with which the inlet flow in the inlet is variable to change the feed rate or the current feed volume P _Z to be processed starting product AP per unit time. This controllable device 23 is via a data connection 24 with the control unit 9 connected.

The aforementioned data connections 18 . 20 . 21 . 24 enable data transfer from or to the control and evaluation unit 9 , They can each be configured as lines or in each case as wireless connections.

Hereinafter, an embodiment of a product-clarification process, which can be performed with the above-described separator, based on the 2 and 3 explained in more detail, being selected as the parameter to be determined in the present embodiment, the degree of turbidity TR, in particular the clear phase KP.

In the drum 1 the separator is preferably continuously fed the starting product AP, where this is clarified. There is a continuous Klarphasenauslass the clear phase KP.

During the clarification of the starting product AP to form the clear phase KP contained in the starting product Trubstoffe and other solids in the solids collection chamber 8th the drum 1 outside the plate pack 14 collected, which fills up. If too many of the solids in the solids collection room 8th accumulated, their outlet begins with the clear phase, which is to be avoided as possible.

In order to monitor the product purification process, a determination - measurement and / or other determination - of the degree of turbidity TR is performed. For this purpose, for example, a measuring cell is used, which is transilluminated to the sensor device 22 to determine the turbidity.

As far as used in the description of the embodiment of the term turbidity, this embodiment is preferred. The term "turbidity" is to be replaced in an embodiment of the method with a determination of another parameter accordingly by the name of this parameter.

The procedure - see 3 - starts in step 100 at a start time t ₀ . At this starting time t ₀ is or a time slot is already defined. In this time window should after previous attempts and tests - which have led to a good clarification - if possible after a final solids discharge the next solid discharge by piston valve 6 occur. The time window is from an initial time t ₁ : = c ₁ (constant 1 ) and an end time t ₂ : = c ₂ (constant 2 ) limited. It is further defined a maximum discharge volume V _M , which should not be exceeded. However, this can also already be specified by the manufacturer or the user.

In addition, or is not to be exceeded in the clarification of the initial product AP maximum limit TR _M is preset for the turbidity TR. The product feed or the feed volume into the drum 1 flowing and there to be clarified starting product per unit time is referred to as P _Z. This quantity is defined and set at the time of initiation t ₀ as 100% of the feed rate of the separator which is possible in the method of purification, which is not mandatory, for example.

The starting time t ₀ corresponds to the time of a final solids discharge at the already running or operating speed of the drum 1 in steady state running or started centrifugal clarification Z-step 200 -, whereupon repeated - z. Continuous - turbidity measurements in / behind the process 13 be performed - step 300 - to determine the current turbidity TR.

A solids discharge E of the solids F from the solids collecting space 8th with the piston valve 6 - Step 400 - is then made when in step 300 it is determined that the determined turbidity value exceeds the maximum turbidity threshold TR _M.

In this case, in one step 500 checked whether the end of the period of time t _E since a final solids discharge up to the currently performed solids discharge within the time window t ₁ to t ₂ , within which the solids discharge should preferably be triggered by the turbidity measurement.

Will in the step 500 determined that -. B. due to an increasing solids content in the product feed - a solid discharge before reaching the start time t _{1 of} the time interval, the solids discharge E in the step 400 was triggered - which means that the solids space in the drum 1 is completely filled, it is checked whether the volume of the next or then current solids discharge V _{E is} still below a threshold V _Max - step 600 , The first time you run this is certainly the case, as has been defined at the start, the V _E <V _M. In this case, therefore, the emptying volume is increased for or during the subsequent solids discharge - step 700 : By way of example, V _{E is} increased by 10% so that V _E NEW = 1.1 · V _E. Thus remains after the next solids discharge - step 400 - less solid in the solids space 8th and in a next cycle can be centrifuged a little longer, so that as far as possible the lower time limit t _{1 is} exceeded before a further solids discharge is triggered.

If the solids content in the product feed rises after several cycles or many cycles, the maximum discharge volume of the centrifuge is insufficient to reach or exceed the starting time t1 of the time interval, after passing through the step 600 alternative to step 700 in one step 800 reduces the feed rate. For this purpose, for example, it is determined: P _Z NEW = 0.9 × P _Z.

The steps 100 to 800 are repeated iteratively until the further evacuation within the emptying time window t ₁ to t _{2 are} triggered and a constant operation with reproducible separation quality is achieved.

In the case that has been determined - step 500 in that the current purge time t _{E is} greater than the time until the start time t _{1 is reached} , it is further checked whether the purge time t _{E is} less than or greater than the time until the end time t ₂ - step 900 ,

If this is the case, the parameters remain unchanged and the centrifugal clarification Z is in step 200 continued unchanged.

However, in the step 900 found that z. B. due to falling solids content in the feed 4 the time period t _E until reaching the end time t 2 of the time interval from the last to the current solids discharge E in step 400 has been exceeded (this means the residence time of the solid in the drum 1 becomes too long, a compaction threatens), ie is in the step 900 found that t _E > t ₂ , again the volume of the emptying volume z. B. on the basis of the duration of solids discharge checks: step 1000 , Will be there - in the step 1000 - determined that the current emptying volume V _E in step 1000 is still greater than the minimum emptying volume V _Min , the emptying volume V _{E of} the subsequent solids discharge is reduced; z. As follows: V _{E NEW} : = 0.9 * V _E ; step 1100 ,

If, on the other hand, the current emptying volume V _{E is} already smaller than the minimum emptying volume V _Min , the product feed P _{Z is} increased; z. As follows: P _{Z NEW} : = 0.9 · P _Z ; step 1120 ,

The steps 100 to 800 or maybe until 1200 are repeated iteratively until the further evacuation within the emptying time window t1 to t2 are triggered and a constant operation with reproducible separation quality is achieved.

2 illustrates essential steps of the 3 in another illustration.

Overall, the illustrated and claimed method product losses are reduced by not optimal draining in a simple manner.

LIST OF REFERENCE NUMBERS

1

drum

2

spindle

3

sensor

4

Intake

5

outlet

6

spool

7

Solid scavengers

8th

Solids collection chamber

9

control unit

10

Drum base

11

drum lid

12

Hood

13

procedure

14

Disc stack

15

Line for hydraulic fluid

16

Valve

17

dosing

18

Data Connection

19

hydraulic line

20

Data Connection

21

Data Connection

22

sensor device

23

Controllable device

24

Data Connection

KP

clear phase

AP

starting product

e

Solid emptying

F

solids

Z

centrifugal clarification

TR

turbidity

TR _M

Maximum turbidity limit

t ₀

Start time procedure

t ₁

Start time interval

t ₂

End time interval

t ₀ , t ₁ , t ₂ ,

timings

t _E

Time of the current emptying

V _E

current emptying volume

V _Max

maximum emptying volume

_Min

minimal emptying volume

P _z

current inflow volume / time unit

P _M

maximum inflow volume / time unit

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 3228074 A1 [0003]
• DE 102005049941 A1 [0030]

Claims (13)

Process for clarifying a flowable starting product (AP) with a centrifuge, in particular a separator with a rotatable drum ( 1 ) with a feed ( 4 ) and at least one liquid outlet ( 13 ) for the continuous discharge of at least one clarified liquid phase - a clear phase - and with discontinuously open solids outlet openings ( 5 ) for the discontinuous discharge of a solid phase solids discharge, characterized by at least the following steps: 100 Setting or determining a time interval which is limited by a start time (t ₁ ) and an end time (t ₂ ), wherein in the time interval a next solids discharge after a previous solids discharge is to take place; 200 By performing a centrifugal clarification of the starting product (AP) in the drum ( 1 ); 300: repeatedly determining at least one actual value of a parameter, in particular a product or method parameter, during the step 200 ; 400 Carrying out a solids discharge when the parameter deviates from a limit value, in particular exceeds a limit value; and 500 . 900 Determining the time (t _E ) of the current solids discharge and check whether this in the time interval from the step 100 lies; and - return to step 200 if the time (t _E ) of the actual solids discharge in the time interval from step 100 lies; - or carrying out a change of a discharge volume for the next solids discharge and / or a product feed volume per unit time, if the time (t _E ) of the current solids discharge is not in the time interval from the step 100 lies. A method according to claim 1, characterized in that in step 100 the following is further defined and / or adjusted: a maximum limit value (TR _M ) for the parameter which is not to be exceeded and which in particular is a turbidity level (TR) of the clear phase; - the volume in the drum ( 1 ) flowing and there to be clarified starting product (AP) per unit time (P _Z ) - called Produktzulaufvolumen-; and / or - the volume at solid (V _E ) to be emptied at the next solids discharge to a value which is less than a maximum value (V _Max ) and greater than a minimum value (V _Min ). Method according to Claim 1 or 2, characterized in that the time interval lies within the following range: 0 sec ≤ t ₂ -t ₁ ≤ .300 sec .. Method according to one of the preceding claims, characterized in that, if in step 500 it is determined that the last solids discharge E of the step 400 was triggered before reaching the start time t _{1 of} the time interval, in one step 700 the emptying volume (V _E ) for the next solids discharge is increased or the product feed volume (P _Z ) per unit time in one step 800 is reduced. A method according to claim 4, characterized in that the emptying volume (V _E ) for the next solids discharge in step 700 is increased if no maximum emptying volume (V _Max ) is reached and that the product feed volume (P _Z ) per unit time in step 800 is reduced when the maximum purge volume (V _Max ) is reached or exceeded. Method according to one of the preceding claims, characterized in that, if in step 900 it is determined that the last solids discharge E of the step 400 was triggered after reaching the end time (t ₂ ) of the time interval, the emptying volume (V _E ) for the next solids discharge in one step 1100 is reduced or the product feed volume (P _Z ) per unit time in one step 1200 is increased. A method according to claim 6, characterized in that the emptying volume (V _E ) for the next solids discharge in step 1100 is decreased when the minimum purge volume ( _Vmin ) has not yet been reached and that the product feed volume ( _Pz ) per unit time is increased in step 1200 when the minimum purge volume ( _Vmin ) is reached or undershot. Method according to one of the preceding claims, characterized in that the product parameter of the clear phase (KP) and / or the starting product (AP) is the degree of turbidity (TR). Method according to one of the preceding claims, characterized in that the product parameters of the clear phase (KP) and / or the starting product (AP) is the viscosity and / or conductivity. Method according to one of the preceding claims, characterized in that the solids outlet through the outlet openings ( 5 ), which by a piston valve ( 6 ) are closed and opened. Method according to one of the preceding claims, characterized in that the determination of the parameter of the clear phase (KP) by at least one sensor device ( 22 ), which is in or on a process ( 13 ) of the separator ( 1 ) is arranged. Method according to one of the preceding claims, characterized in that the determination of the parameter of the starting product (AP) by a sensor device ( 3 ), which is in or at an inlet ( 4 ) of the separator ( 1 ) is arranged. Method according to one of the preceding claims, characterized in that the control of the method by means of a control unit ( 9 ) he follows.

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