Integrated Motor Drive Solutions for Paper and Pulp Mills
Paper mills convert prepared fiber furnish into finished products like containerboard, printing paper, and tissue. Electric motors drive the pumps, fans, blowers, mixers, and other rotating equipment responsible for moving stock, circulating process fluids, controlling air, and overall supporting the papermaking process. Variable speed operation helps regulate stock consistency and flow, maintain pressure, control ventilation, and adapt equipment output as machine operating conditions change.
VIDAR’s integrated variable-speed converter for harsh, corrosive environments removes the complexity associated with traditional VFD installations. Below are unique advantages tied to equipment commonly found in pulp and paper mills:
Condensate Return Pumps
The dryer-section steam systems produce hot condensate which these pumps recycle back toward the boiler or condensate treatment system for reuse and heat recovery. The more returned the merrier, as it’s much more expensive to treat makeup water for turbine and boiler use versus recycled condensate.
Dry run protection and low-load programmable limits can identify loss of liquid or inadequate pump prime, thereby shutting the system down before damage to seals or bearings ensues.
Various Water Pumps
These pumps transfer water to various users in the mill, with white (fiber-containing) water coming from the forming section. This list includes dilution water, seal water, fresh well water, warm well water, boiler feedwater, and water booster pumps.
PID control can lessen wasted energy and improve reliability by controlling tank level, pressure, or flow rates directly. Analog outputs, Ethernet IP, or Modbus TCP can relay monitored process variables back to the distributed control system.
White and Green Liquor Pumps
Each liquor sits in different parts of the kraft recovery cycle and contains caustic or aggressive chemicals. White liquor (sodium hydroxide and sulfide) goes to digesters to chemically separate lignin from wood fibers. From there black or spent cooking liquor (containing dissolved lignin and pulping chemicals) ultimately lands in the recovery boiler. The dissolved smelt from the recovery boiler (green liquor) goes through clarification and recausticizing to become white liquor.
Leak detection can warn operators of a loss in system pressure. Ruggedized and corrosion resistant enclosures protect VIDAR from ambient corrosive gases (tested to ASTM B845 Method K).
Pulp Stock & Slurry Transfer Pumps
These pumps move fiber stock and higher-solids slurries to screens, cleaners, chests, refiners, and machine systems.
Torque and current monitoring can protect the pump and drivetrain during high-consistency transients, plugging, or unexpectedly heavy stock while speed adjusts to maintain the required stock flow.
Supply & Exhaust Dryer Hood Blowers
While often driven by motors with output power in the hundreds, these blowers supply heated air and exhaust moisture-laden air from the dryer hood to control humidity, evaporation, and drying conditions around the paper web.
Skip-frequency programming can prevent excitations of the fan, shaft or structure within the resonance band(s) while airflow is controlled to follow drying demand.
Sludge Pumps
Sludge pumps eject wastewater sludge, fiber rejects, and concentrated solids to the mill’s wastewater treatment facility.
Customizable acceleration rates and curves can help breakup settled sludge after long dormant periods. Over torque protection can warn operators of buildup or blockage in the line.
