1. Pulping system control for rotary spherical digester
Key characteristics of DCS control system adopted during the steaming process: Rotary spherical digester automatic positioning control, mounted pot complete startup control, control of rotary spherical digester volume, liquid ratio control, alkali concentration control, flow control, and incoming steam pressure control for rotary spherical digester.
Overall functional indicators for an optimised control solution
• Reduced volatility in standard deviation between measured valuesof slurry hardness
• Duration shortened by steaming as compared with manual control
• Energy consumption by steaming reduced by 5.2% as compared with manual control
• Coarse pulp yield increased by 2%
• Reduced chlorine consumption by 7.8% during bleaching stage
• Reduced power consumption per unit by 2.9%
• Stable pulp quality (hardness) projection and monitoring control functions
• Improved output stability
2. Consecutive steaming system control
Consecutive steaming system control can be divided into automatic control of pulp liquid level, temperature auto-check and basic control of consecutive steaming.
3. Super replacement steaming system control
Key characteristics: Steaming process is more flexible, pulp quality is more standardised, pulp is stronger, pulp is more bleachable, and yield of bleached pulp is high.
4. APMP pulp-making
Key DCS control solution includes: Pre-steamed washing control, primary soaking control, secondary soaking control, primary groundwood pulp control, secondary groundwood pulp control, and the pre-activation debugging and control of the large grinder.
5. Deinked pulp system control
Key deinked-pulp system control solutions: D-shaped hydrapulper + hydro slag control, automatic backwash control for screening system, sealed screening control,flotation deinking control, and heat dispersion system control.
6. Pulp selection, washing, and bleaching CI02 preparation process control solution
The pulp selection, washing, and bleaching CI02 preparation process control solution includes air-tight screening control, bleaching control, and CI02 production process and control.