1. Advanced Process Modeling Improves Efficiency Process Simulations Ltd. 206-2386 East Mall, Vancouver, BC, V6T 1Z3 www.psl.bc.ca Dave Stropky and Jerry Yuan

2. Contents  Introduction to Process Modeling  Examples  Recovery and Power Boilers  Lime Kilns  Aerated Wastewater Lagoons  Precipitators

3. Process Modeling Principle of Conservation Mass Momentum Energy ……. IN = OUTINOUT OUT 3D CFD

4. CFD Modeling Examples Building Structures Jet engines Weather Aircraft Industrial Equipment

5. Process Modeling INPROGRESSINDUSTRIALAPPLICATION Literature review Plant\Mill interaction Process knowledge Commitment of industry Physical model Numerical model Model development Model validation Industrial testing Parametric studies Problem Solving Model proposed retrofits Equipment Optimization Cost Reduction INITIALSTAGE

6. Pulp and Paper Modeling Applications

7. Recovery and Bark Boilers

8.  Analyze the existing air and fuel system  Improve gas mixing and combustion effectiveness  Lower excess air necessary for complete combustion  Minimize particulate carryover and unburned char  Minimize emissions of CO2, CO, TSR, and NOx  Increase the range of operational conditions  Improve overall thermal efficiency  Optimize firing strategies for different loads/fuels  Increase the capacity of the boiler  Improve the stability of the boiler  Minimize the danger of bed blackouts  Minimize the danger of waterwall tube failure  Provide valuable operational information for mill personnel Boilers

9. Air System Evaluation

10. Boilers Emission Control

11. Boilers Efficiency Improvements

12. Lime Kilns

13.  Reduce fuel consumption. Improve Efficiency  Adjust primary/secondary air and fuel ratios and burner settings to maximize kiln efficiency  Identify and eliminate thermal hot spots that lead to reduced brick liner lifetime  Develop strategies for reducing ring formation  Identify and fix problems with kiln performance due to hood shape and secondary air ports location and size  Evaluate NCG injection alternatives - optimize injection  Evaluate alternative fuels  Minimize emissions  Optimize heat transfer to mud  Improve combustion stability through retrofit and adjustment of the burner and burner structure Lime Kilns

14. Gas Temperature Brick Temperature

15. Lime Kilns

17. Aerated Wastewater Lagoons

18. Aerated Wastewater Lagoons  Improve efficiency of waste treatment (BOD removal) by optimizing number and placement of mechanical aerators.  Reduce power consumption from mechanical aerators by either minimizing the number of aerators required or reducing the power load per aerator.  Reduce nutrient supplementation (added phosphorus and nitrogen)  Reduce dredging frequency  Improve design of lagoon basins

19. Aerated Wastewater Lagoons Hydraulic Flow and Residence Time

20. Aerated Wastewater Lagoons Predicted RTD Curves T peak / T mean = 0.74 T median / T mean = 0.91

21. Aerated Wastewater Lagoons Predicted Biology

22. Precipitators

23.  Improve precipitator efficiency by redistributing gas flow  Improve duct designs  Optimize porous distribution on perforate plates and locations of plates  Optimize baffle and vane designs

24. Precipitators

25. -10% 0% 10% 20% 30% 40% 50% 60% 70% 80% Outlet Velocity Profile Factor % Reduction in Particulate Emissions Modified Inlet Unmodified Inlet

26. Conclusions The performance of many pulp and paper processes is governed by the fluid dynamics, heat transfer, and chemical reactions in the associated equipment. Much of this equipment was and still is designed and troubleshot using traditional methods. We know what goes in and comes out, but we normally don’t know clearly and in detail what is going on inside. Advanced three-dimensional process modeling provides a clearer picture of the process dynamics. This knowledge helps mill engineers and operators improve process efficiency and reduce costs.