CIMExcel Software Inc. Slide 1

CIMExcel Software Inc. Slide 1

Advanced Drystock Control (ADC)to reduce the ‘residual’ basis weight, moisture, and caliper profiles

CIMExcel Software Inc.

Control Systems Engineering company located in Vancouver, Canada.

Provides Simulators, Advanced Control and Optimization Systems for,

• Pulp and Paper Industry

• Energy and Power Industry

• Mineral Processing Industry

• Nuclear Industry

Pulp and Paper:

• Advanced Paper Machine Control (APMC)

• Roll Quality Optimization (RQO) and Trim Optimization

• Pulp Quality Analysis (PQA)

• Advanced Boiler Control (ABC)

• Energy Management System (EMS)


Space - Time Control of Paper Machine Basis Weight, Moisture, Caliper and Coat Weight

Advanced Paper Machine Control (APMC) significantly reduces the variability of basis weight, moisture, caliper and coat weight for all grades and speeds.

APMC improves grade transition performance.

APMC consists of two parts,

• Advanced Drystock Control (ADC) for MD Control

• Modal Profile Control (MPC) for CD Control

Advanced Drystock Control (ADC) consists of two parts,

• ADC - Thickstock

• ADC - Thinstock


Space - Time Control of Paper Machine Basis Weight, Moisture, Caliper and Coat Weight

• The ‘noisy / residual’ CD scans are actually aliased MD variability which is within the scanner scanning time.

• Approximately 80-90 % of the variability of headbox consistency and total head is in the 2 - 50 second range,

and 30-60 % of this variability is in the 2 - 5 second range, and is completely aliasing the scanner CD profile.

• Feedforward ADC (thinstock and thickstock) is required in order to reduce the ‘residual’ CD profile.

unconditioned

CD Scans‘flat’ actuators

CD Reel average

CD

improvement

~ 0.55 %

total improvement

~ 1.27 %

‘Residual’

‘optimized’ actuators


MD to CD Aliasing Problem and Variability Analysisstrong correlation of short term (2 – 5 seconds) variability

single

point

scanner

operation

~ 50 second CD scan time

8 scan average

100 boxes

8 scan average

100 boxes

8 scan average

100 boxes

30 scan average

440 boxes

spatially filtered

~ 50 seconds

headbox consistency

headbox total head


Variability Analysis

Time Series Data (sampled at 1 cps)

PowerSpectrum

Highest Frequency (0.5 cps, 2 second period)

Lowest Frequency (0.000116 cps, 832 second period)

Recirculation Flow Control2 – 3 second period (0.33 – 0.50 cps)

Drystock Feedback Control25 – 250 second period (0.004 – 0.04 cps)

Drystock Feedforward Control15 – 25 second period (0.04 – 0.07 cps)

Headbox Consistency Control6 – 15 second period (0.07 – 0.17 cps)

Total Head Control6 – 3 second period (0.17 – 0.33 cps)

Single Point Dry Weight (gsm)

Possible Wet-End Sources


Variability Analysis (for variables with 2 - 50 second periods of variation - within the CD scanning time)

MD Variables Thinstock Variables Thickstock Variables • Size Press / Reel Basis Weight• Size Press / Reel Dry Weight• Coater Basis Weight• Rush - Drag• Vertical Slice• Horizontal Slice• Press Section PLI• Couch Pressure• Scanner Beta Signal• Scanner IR Signals• Scanner Basis Weight• Scanner Dry Weight• Scanner Moisture• Scanner Water

• Total Head• Headbox Consistency• Front-Back Differential

Pressure• Stream Valve• Stream Flow• Stock Flow• Cleaner Reject Flows• Screen Reject Flow• Fan Pump Speed

• Basis Weight Valve• Furnish LD Consistency• Furnish LD Dilution Valve• Broke Chest Consistency• Broke Chest Dilution Valve• Blend Chest Consistency• Blend Chest Dilution Valve• Machine Chest Consistency• Machine Chest Dilution Valve• Stuff Box Consistency• Thickstock Consistency


Performance Analysis Toolkit for

Variability Analysis of MD, Thinstock and Thickstock Variables

High Speed NI-DAQ

Signal Processing and Filtering

Time Series Analysis

Backlash - Transport

Power Spectral Analysis


Advanced Drystock Control


signal analysismulti-actuator responsecoordination and optimization

Headbox Consistency

Total Head

Thinstock Flows

Thinstock Consistencies

Thickstock Flows

Thickstock Consistency

Main Dilution

Individual Dilution

Main Slice

Individual Actuators

Basis Weight Valve

New Devices

Feedforward Control:


Advanced Drystock Control - Thickstock

• requires high speed data acquisition and signal processing equipment.

• requires some instrumentation - control device, and possible process reconfiguration.

• new thickstock control programming and tuning services.

transport model, backlash compensator, discrete time control, additives and consistency

feedforward


Advanced Drystock Control - Thinstock


consistency feedforwardtransport

multi actuator response optimization

Headbox Consistency

Total Head

Thinstock Flows

Thinstock Consistencies

Main Dilution

Individual Dilution

Main Slice

Individual Actuators

New Devices

• Requires an optical thinstock consistency transmitter strategically located on the headbox approach.

• Requires high speed data acquisition and signal processing equipment.

• Thinstock and headbox analysis and control tuning services.

• Identification of process related variability.

• Possible process-related variability reduction solutions.

• Response analysis testing of potential actuators.

• Possible process equipment and control additions.

• Coordination and optimization of multiple actuators.

• Scanner single point operation required for tuning and optimization.


Scanner Basis Weight β Signal Corrections

• The scanner basis weight β voltage has a noisy and lagged response as shown in the above displays.

• Some scanner β noise filtering be may be applied which increases the scanner basis/dry weight response lag.

• For a scanner CD speed of 20 cm/s,

the lagged response (without filtering) affects 4 cm of the basis/dry weight CD width and needs to be corrected,

the lagged response (with filtering) affects 10 cm of the basis/dry weight CD width and needs to be corrected.

In single point mode, some attenuation will occur for the 2.0 second period basis/dry weight variability.


Advanced Drystock Control Project Activitiesto reduce the ‘residual’ basis weight, moisture, and caliper profiles

1. Overview Analysis and Report - Proposal

> Scanner Signal Analysis and Correction.

> Scanner MD-CD Basis Weight , Dry Weight, and Water baseline performance.

> Survey of Thinstock, Thickstock Instrumentation, DCS Loops and Control Devices.

> Thinstock and Thickstock Variability Analysis.

> Thickstock Control Device Analysis.

> Thinstock Control Device Analysis.

2. Thickstock - Detailed Analysis, Design, and Report

3. Thickstock - ADC System (PC-> DCS)

4. Thinstock - Detailed Analysis, Design, and Report

5. Thinstock - ADC System (PC -> DCS)

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CIMExcel Software Inc. Slide 1