Method and device arrangement for automatic dose control of chemicals

• US 8,515,581 B2
• Filed: 08/27/2004
• Issued: 08/20/2013
• Est. Priority Date: 08/29/2003
• Status: Active Grant

• Current Assignee: Kemira Oyj
• Original Assignee: Kemira Oyj
• Inventors: Piironen, Eila, Juuso, Esko, Joensuu, Iiris, Sorsa, Aki
• Primary Examiner(s): Gordon, Brian R
• Assistant Examiner(s): Sasaki, Shogo
• Application Number:
  US10/568,102
• Publication Number:
  US 20080046127A1
• Time in Patent Office: 3,280 Days
• Field of Search: 700/266, 700/4, 700/8, 700/9, 700/267, 700/271, 700/282
• US Class Current: 700/271
• CPC Class Codes: C02F 1/008 Control or steering systems not provided for elsewhere in subclass C02F
• CPC Class Codes: C02F 1/52 by flocculation or precipitation of suspended impurities C02F1/463 takes precedence
• CPC Class Codes: C02F 1/56 Macromolecular compounds
• CPC Class Codes: C02F 2209/001 Upstream control, i.e. monitoring for predictive control
• CPC Class Codes: C02F 2209/003 Downstream control, i.e. outlet monitoring, e.g. to check the treating agents, such as halogens or ozone, leaving the process
• CPC Class Codes: C02F 2209/006 comprising a software program or a logic diagram
• CPC Class Codes: C02F 2209/008 comprising telecommunication features, e.g. modems or antennas
• CPC Class Codes: C02F 2209/11 Turbidity
• CPC Class Codes: G05B 13/0275 using fuzzy logic only
• CPC Class Codes: G05D 11/135 by sensing at least one property of the mixture G05D11/139 takes precedence

Abstract

The present invention relates to a method for automatic dose control of chemicals in liquid treatment, particularly for automatic dose control of chemicals in water treatment. The present invention also relates to a device arrangement for automatic dose control of chemicals. The invention utilizes adaptive linguistic equation controllers for dosing the chemicals.

Claims

1. A method for automatic dose control of one or more chemicals in a liquid treatment system, which comprises:

inputting properties of a liquid measured on-line as input variables i into a predefined adaptation model to output an adaptation coefficient, wherein the adaption coefficient is calculated by equation

2. The method of claim 1, wherein a linguistic equation associated with said adaptive linguistic equation (LE) controller is a dynamic linguistic equation.

3. The method of claim 1, wherein a linguistic equation associated with said adaptive linguistic equation (LE) controller is a static linguistic equation.

4. The method of claim 1, wherein a linguistic equation associated with said adaptive linguistic equation (LE) controller is a non-linear linguistic equation.

5. The method of claim 1, wherein said feedback LE controller is configured to determine a change of control of said adaptive LE controller based on a difference between an output of said system and a setpoint.

6. The method of claim 1, wherein said adaptive LE controller further includes a feedforward controller configured to determine the dosing of one or more chemicals to the liquid by compensating for process disturbances in advance.

7. The method of claim 1, further comprising:

improving control by changing one or more treatment process requirements or fitting a set point to one or more process requirements of one or more liquid treatment sub-processes, using one of more cascade controllers connected to said adaptive LE controller.

8. The method of claim 1, wherein one of said properties of the liquid is a quality index of the liquid.

9. The method of claim 8, wherein said quality index is purity index.

10. The method of claim 1, wherein said liquid is water.

11. The method of claim 1, wherein said liquid treatment system is a water purification system.

12. The method of claim 1, wherein said chemicals are coagulants, flocculants, oxidants, reductants, adsorbents, dispersing agents, biocides, defoamers, or combinations thereof.

13. The method of claim 1, wherein said liquid includes incoming liquid which enters said liquid treatment system, and said properties of the liquid are defined from said incoming liquid.

14. The method of claim 1, said method further comprising:

treating the liquid using said dosage for said one or more chemicals, and

measuring outgoing, treated liquid which exits said liquid treatment system, to define said properties of the liquid which are inputted into said predefined adaptation model.

15. The method of claim 1, wherein said predefined adaptation model is a LE-model.

16. The method of claim 1, wherein said predefined adaptation model is a fuzzy model.

17. The method of claim 1, wherein an adaptation performed by said predefined adaptation model is performed by remote operation, whereby one or more parameters of said adaptation model is/are evaluated or updated by a remote processor in connection with a remote data system.

35. The method of claim 1, said method further comprising:

controlling the dosing to the liquid, of another chemical of a different type from said one or more chemicals, using a feedforward controller but not using said feedback LE controller, to output a dosage for said another chemical.

18. A device arrangement for automatic dose control of one or more chemicals in a liquid treatment system, said device arrangement comprising:

one or more predefined adaptation subsystem controllers configured to input properties of a liquid measured on-line as input variable i into a predefined adaptation model and output at least one adaptation coefficient, where the adaptation coefficient is calculated by equation

19. The device arrangement of claim 18, wherein a linguistic equation associated with said adaptive linguistic equation (LE) controller is a dynamic linguistic equation.

20. The device arrangement of claim 18, wherein a linguistic equation associated with said adaptive linguistic equation (LE) controller is a static linguistic equation.

21. The device arrangement of claim 18, wherein a linguistic equation associated with said adaptive linguistic equation (LE) controller is a non-linear linguistic equation.

22. The device arrangement of claim 18, wherein said adaptive LE controller includes a feedforward controller.

23. The device arrangement of claim 18, wherein said device arrangement comprises one of more cascade controllers connected to said adaptive LE controller, said one or more cascade controllers being configured to improve control by changing one or more treatment process requirements or fitting a set point to one or more process requirements of one or more liquid treatment sub-processes.

24. The device arrangement of claim 18, wherein said one or more predefined adaptation subsystem controllers are configured to input said properties of the liquid which are described by quality index.

25. The device arrangement of claim 24, wherein said quality index is purity index.

26. The device arrangement of claim 18, wherein said liquid is water.

27. The device arrangement of claim 18, wherein said liquid treatment system is a water purification system.

28. The device arrangement of claim 18, wherein said adaptive linguistic equation (LE) controller is modified adaptively to control the dosing of one or more chemicals which are coagulants, flocculants, oxidants, reductants, adsorbents, dispersing agents, biocides, defoamers, or combinations thereof, and

said adaptive linguistic equation (LE) controller is modified adaptively to output a dosage for said one or more chemicals.

29. The device arrangement of claim 18, wherein

said liquid includes incoming liquid which enters said liquid treatment system, and

said one or more predefined adaptation subsystem controllers inputs said properties of the liquid which are defined from said incoming liquid.

30. The device arrangement of claim 18, wherein

said liquid treatment system treats the liquid using said dosage for said one or more chemicals, and measures outgoing, treated liquid which exits said liquid treatment system, and

said one or more predefined adaptation subsystem controllers is configured to input said properties of the liquid which are defined from said outgoing, treated liquid which exits said liquid treatment system.

31. The device arrangement of claim 18, wherein one of said one or more predefined adaptation subsystem controllers is a LE-model subsystem.

32. The device arrangement of claim 18, wherein one of said one or more predefined adaptation subsystem controllers is a fuzzy model subsystem.

33. The device arrangement of claim 18, wherein an adaptation process of said one or more predefined adaptation subsystem controllers is performed by remote operation whereby one or more parameters of said one or more adaptation subsystem controllers is/are evaluated and/or updated by a remote processor in connection with a remote data system.

34. The device arrangement of claim 18, said device arrangement further comprising an analyzer which includes an implemented software module or device representing measurement handling routines for monitoring said device arrangement.

36. The device arrangement of claim 18, wherein said adaptive LE controller is configured, based on said adaptive change of control, to control the dosing of said one or more chemicals to the liquid and output a dosage for said one or more chemicals for said liquid treatment system,

said device arrangement further comprising a feedforward controller configured to control, without using said feedback LE controller, the dosing of another chemical to the liquid and output a dosage for said another chemical for said liquid treatment system,

wherein said another chemical is of a different type from said one or more chemicals.