METHOD AND ARRANGEMENT FOR CONTROLLING A DEWATERING PROCESS

• US 20200129887A1
• Filed: 02/10/2017
• Published: 04/30/2020
• Est. Priority Date: 02/10/2017
• Status: Active Grant

• Current Assignee: Metso Outotec Finland OY (Metso Outotec Oyj)
• Original Assignee: Outotec (Finland) Oy (Metso Outotec Oyj)
• Inventors: KOSONEN, Mika, KAUVOSAARI, Sakari
• Granted Patent: US 11,224,829 B2
• Time in Patent Office: Days
• CPC Class Codes: B01D 21/01 using flocculating agents for purifying water C02F1/52; for liquid radioactive waste G21F9/10
• CPC Class Codes: B01D 21/08 provided with flocculating compartments
• CPC Class Codes: B01D 21/14 with rotating scrapers
• CPC Class Codes: B01D 21/2427 The feed or discharge opening located at a distant position from the side walls
• CPC Class Codes: B01D 21/30 Control equipment
• CPC Class Codes: B01D 21/302 Active control mechanisms with external energy, e.g. with solenoid valve
• CPC Class Codes: B01D 21/32 Density control of clear liquid or sediment, e.g. optical control ; Control of physical properties
• CPC Class Codes: B01D 21/34 Controlling the feed distribution; Controlling the liquid level ; Control of process parameters
• CPC Class Codes: C02F 1/5281 Installations for water purification using chemical agents
• CPC Class Codes: C02F 2209/10 Solids, e.g. total solids [TS], total suspended solids [TSS] or volatile solids [VS]
• CPC Class Codes: C02F 2209/11 Turbidity
• CPC Class Codes: C02F 2209/40 Liquid flow rate
• CPC Class Codes: C02F 2209/42 Liquid level
• CPC Class Codes: G05B 13/04 involving the use of models or simulators
• CPC Class Codes: G05B 13/042 in which a parameter or coefficient is automatically adjusted to optimise the performance
• CPC Class Codes: G05B 13/048 using a predictor
• CPC Class Codes: G05B 15/00 Systems controlled by a computer G05B13/00, G05B19/00 take precedence; automatic controllers with particular characteristics G05B11/00

Abstract

An arrangement and a method for controlling a dewatering process including measuring values representing operating parameters of the gravitational sedimentation device and using the values as input values for a predictive multivariable model for predicting an operating state of the gravitational sedimentation device. The disclosure further relates to obtaining reference values for the operating parameters, determining at least one predicted output for an operating parameter of the gravitational sedimentation device, and comparing the predicted output to at the reference values to determine control values that will affect changes in operation of the gravitational sedimentation device.

Claims

1-33. -33. (canceled)

34. An arrangement for controlling a dewatering process comprising:

a gravitational sedimentation device comprising a tank, a lip for removing overflow from the tank and at least one underflow line for removing underflow from the tank;

a first and a second sensor for measuring a first and a second operating parameter representing the material consistency of the underflow from the gravitational sedimentation device and the inventory level of the gravitational sedimentation device, respectively; and

a controller for monitoring and adjusting operating parameters of the gravitational sedimentation device;

at least one memory comprising computer program code, the at least one memory and the computer program code configured to cause the controller to;

receive a first set of values representing the first operating parameter from the first sensor and a second set of values representing the second operating parameter from the second sensor;

use at least the first set of values received from the first sensor and the second set of values received from the second sensor as input values for a predictive multivariable model for predicting an operating state of the gravitational sedimentation device;

wherein the operating state is at least partially dependent on the operating parameters;

determine, using the predictive multivariable model, at least one predicted output for an operating parameter of the gravitational sedimentation device for at least one future point in time;

obtain a set of one or more reference values for the operating parameters of the gravitational sedimentation device;

perform a comparison between the at least one predicted output and at least one reference value from the set of one or more reference values;

determine, based on the comparison, at least one set of one or more control values for at least one control parameter of the gravitational sedimentation device;

wherein the at least one control parameter may at least partially determine the operating state of the gravitational sedimentation device; and

adjust, using the at least one set of control values, at least one control parameter of the gravitational sedimentation device;

wherein the arrangement comprises a third sensor for measuring a third operating parameter representing the turbidity or solids content of the overflow; and

the at least one memory and the computer program code are additionally configured to receive a third set of values representing the third operating parameter from the third sensor;

wherein the third input is additionally included as input values for the predictive multivariable model.

38. The arrangement according to clam 33, wherein the sets of measured values are time series values.

51. A method for controlling a dewatering process in a gravitational sedimentation device, wherein the method comprises:

measuring at least a first and a second set of one or more values representing operating parameters of the gravitational sedimentation device;

the first set representing the material consistency of the underflow and the second set representing the inventory level;

obtaining a set of one or more reference values for the operating parameters of the gravitational sedimentation device;

using at least the first set and the second set as input values for a predictive multivariable model for predicting an operating state of the gravitational sedimentation device;

wherein the operating state is at least partially dependent on the operating parameters;

determining, using the predictive multivariable model, at least one predicted output for an operating parameter of the gravitational sedimentation device for at least one future point in time;

perform a comparison between the at least one predicted output and at least one reference value from the set of reference values;

determining, based at least partially on the comparison, at least one set of one or more control values for at least one control parameter of the gravitational sedimentation device;

wherein the at least one control parameter may at least partially determine the operating state of the gravitational sedimentation device; and

adjusting, using the at least one set of control values, at least one control parameter of the gravitational sedimentation device;

wherein the method comprises measuring a third set of one or more values representing operating parameters of the gravitational sedimentation device;

the third set representing the turbidity or solids content of the overflow;

wherein the third set is additionally included as input values for the predictive multivariable model.