Method for controlling a process

Patent metadata

Field	Value
Publication number	US-10509376-B2
Application number	US-201514952118-A
Country	US
Kind code	B2
Filing date	Nov 25, 2015
Priority date	Dec 2, 2014
Publication date	Dec 17, 2019
Grant date	Dec 17, 2019

Abstract

A method for controlling a process, comprising treatment of a process medium, and which includes a system input, in particular, an inlet, and a system output, in particular, an outlet for the process includes such a dead time profile that a change in at least one parameter of the first type of the process medium at the system input causes a change in at least one parameter of the second type of the process medium at the system output only after an elapse of a dead time, comprises: determining, in particular, digital values for the parameter of the first type and using these values as input values of a control system; determining the set values for an output variable influencing the parameter of the second type of the process medium at the system output, using the determined values of the parameter of a first type and a first proportionality factor recorded in the control system; applying the determined set values for adjusting the output variable using the control system; determining, in particular, digital values for the parameters of the second type; determining the deviation values, which are representative of a deviation of the parameter of the second type from the parameter of the first type, from the determined values of the parameter of the first type and the determined values of the parameter of the second type; and use of at least one of the deviation values and at least one of the set values to determine a second proportionality factor.

First claim

The invention claimed is:

1. A method for controlling a treatment process which includes a system input and a system output, the method comprising:
treating a process medium of the process for an analyte, wherein the process includes a dead time such that a change in an input analyte concentration or analyte load of the analyte in the process medium at the system input causes a change in an output analyte concentration or analyte load of the analyte in the process medium at the system output only after elapse of the dead time;
determining first digital values for the input analyte concentration or analyte load using a first measuring device disposed at or near the system input and using the first digital values as input values of a control system that includes an electronic control device;
determining set values, using the control system, for an output variable representing a dose of a reactant to be added to the process medium to react with the analyte, thereby influencing the output analyte concentration or the analyte load at the system output, based on the first digital values and a first proportionality factor recorded in the control system;
adjusting the output variable according to the set values using an adjustment mechanism in communication with the electronic control device:
adding the dose of the reactant represented by the adjusted output variable to the process medium;
determining second digital values for the output analyte concentration or analyte load at the system output using a second measuring device disposed at or near the system output;
determining deviation values representative of a deviation of the output analyte concentration or analyte load at the system output from the input analyte concentration or analyte load at the system input, the deviation values determined from the first digital values and the second digital values using the electronic control device; and
using at least one of the deviation values and at least one of the set values to determine a second proportionality factor using the electronic control device.

2. The method according to claim 1 , further comprising:
comparing the second proportionality factor with the first proportionality factor.

3. The method according to claim 1 , further comprising:
storing the second proportionality factor in the control system in place of the first proportionality factor.

4. The method according to claim 3 , wherein:
determination of the set values for the output variable using the control system from newly determined first values of the input analyte concentration or analyte load and the second proportionality factor is continued after storing the second proportionality factor in the control system in place of the first proportionality factor.

5. The method according to claim 1 , wherein:
the second values of the output analyte concentration or analyte load, or values of a measured variable from which the output analyte concentration or analyte load is derived, are additionally supplied as control variables to a controller, the controller configured to determine output values of the output variable based on a comparison of the second digital values, or the values of the measured variable from which the output analyte concentration or analyte load is derived, with a predetermined setpoint value of the output variable; and
output values of the output variable are included additively in the determination of the set values.

6. The method according to claim 1 , wherein:
the first digital values are determined such that a sequence of the first digital values represents a chronological development of the input analyte concentration or analyte load; and
the second digital values for the output analyte concentration or analyte load are determined such that a sequence of the second digital values represents a chronological development of the output analyte concentration or analyte load.

7. The method according to claim 1 , wherein:
each of the deviation values are determined by calculating the difference between a corresponding first digital value of the input analyte concentration or analyte load and a corresponding second digital value of the output analyte concentration or analyte load.

8. The method according to claim 7 , wherein:
the deviation values are cumulated by a first counter;
the set values or associated values are cumulated using a second counter; and
the second proportionality factor is determined at a predetermined time on the basis of counter readings of the first and of the second counter resulting from said cumulating.

9. The method according to claim 1 , wherein:
the process is one for treating wastewater in a wastewater treatment plant;
the input analyte concentration or analyte load is an analyte load of an analyte of the wastewater, resulting from the concentration of the analyte in the wastewater and a volumetric flow of the wastewater at the inlet of a treatment stage of the wastewater treatment plant; and
the output analyte concentration or analyte load is the analyte load of the wastewater, which is measurable at an outlet of the treatment stage or downstream to the outlet of the treatment stage and results from the concentration of the analyte in the wastewater and the volumetric flow of the wastewater.

10. The method according to claim 9 , wherein:
the output variable is a variable influencing the analyte concentration in the wastewater.

11. The method according to claim 9 , wherein:
the deviation values represent a decomposition load of the analyte.

12. The method according to claim 9 , wherein:
the analyte is phosphate, and the analyte load is a phosphate load.

13. The method according to claim 10 , wherein:
the output variable is a volumetric or mass flow of a precipitant.

Assignees

• Endress Hauser Conducta Ges Fuer Mess Und Regeltechnik Mbh Co Kg
• Endress Hauser Conducta Gmbh Co Kg

Inventors

• Alber Thomas
• Albert Joachim

Classifications

• C02F2209/001

  Upstream control, i.e. monitoring for predictive control · CPC title

• G05B15/02 Primary

  electric · CPC title

• C02F2209/18

  PO4-P · CPC title

• C02F2209/005

  Processes using a programmable logic controller [PLC] · CPC title

• C02F2209/003

  Downstream control, i.e. outlet monitoring, e.g. to check the treating agents, such as halogens or ozone, leaving the process · CPC title