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  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) CIMExcel Software Inc. Slide 1

  2. 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 CIMExcel Software Inc. Slide 2

  3. Space - Time Control of Paper Machine • Basis Weight, Moisture, Caliper and Coat Weight unconditioned CD Scans ‘flat’ actuators ‘Residual’ CD Reel average CD improvement ~ 0.55 % total improvement ~ 1.27 % ‘optimized’ actuators • 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. CIMExcel Software Inc. Slide 3

  4. MD to CD Aliasing Problem and Variability Analysis • strong correlation of short term (2 – 5 seconds) variability spatially filtered single point scanner operation 8 scan average 100 boxes 8 scan average 100 boxes headbox consistency 8 scan average 100 boxes 30 scan average 440 boxes headbox total head ~ 50 second CD scan time ~ 50 seconds CIMExcel Software Inc. Slide 4

  5. Variability Analysis Single Point Dry Weight (gsm) Time Series Data (sampled at 1 cps) Power Spectrum Highest Frequency (0.5 cps, 2 second period) Lowest Frequency (0.000116 cps, 832 second period) Recirculation Flow Control 2 – 3 second period (0.33 – 0.50 cps) Possible Wet-End Sources Total Head Control 6 – 3 second period (0.17 – 0.33 cps) Headbox Consistency Control 6 – 15 second period (0.07 – 0.17 cps) Drystock Feedforward Control 15 – 25 second period (0.04 – 0.07 cps) Drystock Feedback Control 25 – 250 second period (0.004 – 0.04 cps) CIMExcel Software Inc. Slide 5

  6. 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 • 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 • Total Head • Headbox Consistency • Front-Back Differential Pressure • Stream Valve • Stream Flow • Stock Flow • Cleaner Reject Flows • Screen Reject Flow • Fan Pump Speed CIMExcel Software Inc. Slide 6

  7. Performance Analysis Toolkit for Variability Analysis of MD, Thinstock and Thickstock Variables High Speed NI-DAQ Time Series Analysis Power Spectral Analysis Backlash - Transport Signal Processing and Filtering CIMExcel Software Inc. Slide 7

  8. Advanced Drystock Control Advanced Drystock Control signal analysis multi-actuator response coordination and optimization Feedforward Control: 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 CIMExcel Software Inc. Slide 8

  9. Advanced Drystock Control - Thickstock transport model, backlash compensator, discrete time control, additives and consistency feedforward • 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. CIMExcel Software Inc. Slide 9

  10. Advanced Drystock Control - Thinstock Advanced Drystock Control consistency feedforward transport multi actuator response optimization Main Dilution Individual Dilution Main Slice Individual Actuators New Devices Headbox Consistency Total Head Thinstock Flows Thinstock Consistencies • 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. CIMExcel Software Inc. Slide 10

  11. Scanner Basis Weight βSignal 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. CIMExcel Software Inc. Slide 11

  12. Advanced Drystock Control Project Activities to reduce the ‘residual’ basis weight, moisture, and caliper profiles • 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) CIMExcel Software Inc. Slide 12

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