Level Instrumentation for Pulp and Paper Process Applications

Welcome to our third blog installment about level instrumentation for pulp and paper process applications. As pulp and paper operations face increasing competition, as well heightened demand for conservation and carbon mitigation initiatives, facility managers are closely assessing ways to improve process efficiency. Accurate, reliable level control throughout a pulp and paper plant can be a critical source for process improvement.

In this blog article, we address the application of level instrumentation in plant-wide operations including MC pump standpipes, water storage, chemicals and additives, and lubrication and hydraulic oils.

For quick access to prior posts on the topic of pulp and paper processing efficiency, you can view our first blog, which covers chipping, pulping, washing, bleaching, stock prep, blending and papermaking processes, or visit our second post, which features turpentine and liquor recovery.

Pulp and Paper Process 3MC PUMP STANDPIPES
MP Pump StandpipeApplication: Designed to move thick fluids, MC (medium consistency) pumps are ideal for transporting pulp in a mill. Pulp is often pumped from a standpipe, a vertical feed pipe integral to the pump. Pumps with standpipes typically pump to and from washers and thickeners, O2 and CLO2 mixers, extraction towers, bleach storage towers and high-density pulp storage towers.

Challenges: It is important that the proper level of pulp be maintained in a standpipe. A level control in the standpipe does this by actuating a valve downstream of the pump. A malfunctioning level control could result in standpipe overflow, or cause a pump to operate in a no-flow condition in which it would quickly sustain damage through overheating and seal damage.

Level Technologies:
– Thermatel® Thermal Dispersion Switch for point level
– Eclipse® Guided Wave Radar Transmitter for continuous level

MILL WATER STORAGE
Mill Water StorageApplication: Because pulp is processed and paper is made in an aqueous vehicle that is up to 99.5% water, water management is essential for productive mill operations. Level controls monitor the storage of cold, warm and hot process water, potable water, boiler feedwater, liquor production water, process wastewater, and open effluent weirs, sumps, and stormwater basins.

Challenges: Process, reclaimed and service water storage may range from small tanks to
large bulk tanks with heights of 40 feet (12.2 meters). Controls are specified according to the size and geometry of the bulk storage vessel. Level controls in open atmosphere reservoirs must withstand punishing weather conditions. Firewater storage must conform to NFPA standards.

Level Technologies:
– Model A15 Series Displacer-Actuated Switch or Echotel® Ultrasonic Switch for point level
– ECHOTEL Non-Contact Ultrasonic Transmitter, ECLIPSE Guided Wave Radar Transmitter or Pulsar® Non-Contact Radar Transmitter for continuous level
– Atlas® Magnetic Level Indicator for visual indication

CHEMICAL AND ADDITIVE STORAGE
Chemical and Additive Storage
Application: Chemical stocks stored in mills include acids and alkalies, delignification chemicals, bleaching agents and water treatment chemicals. Chemical additives mixed into the process stream at the wet end of the paper machine include dyes and pigments, drainage aids, defoamers, slimicides, and a broad range of specialty chemicals that improve paper performance.

Challenges: Chemical solution storage and day tanks require stringent level monitoring. Though precise chemical measurement is accomplished by metering pumps, tank level controls actuate tank-filling operations and protect against overfilling. Tank size and geometry, the presence of mixing hardware, and the solution’s chemical nature are prime factors in level instrument selection.

Level Technologies:
– Model A15 Series Displacer-Actuated Switch or ECHOTEL Ultrasonic Switch for point level
– ECHOTEL Non-Contact Ultrasonic Transmitter, ECLIPSE Guided Wave Radar Transmitter or PULSAR Non-Contact Radar Transmitter for continuous level
– ATLAS Magnetic Level Indicator for visual indication

LUBRICATION AND HYDRAULIC OIL
Lubrication and Hydraulic OilApplication: Pulp and paper mills operate many machines that require lubrication. Lubricants prevent damage caused by excessive friction and prolong component and equipment life. Oil is stored in stainless steel and carbon steel tanks. While gearboxes hold up to 50 gallons, and hydraulic reservoirs up to 200 gallons, a paper machine may contain up to 5,000 gallons of lubricant.

Challenges: Level monitoring of oil reservoirs will ensure the proper functioning of pumps, gearboxes, drives, compressors, bailing presses, materials handling equipment and paper machines. Temperature shifts in oil reservoirs affect media density that excludes some technologies, such as pressure transmitters. Because ISO cleanliness levels increase oil change frequency, controls should be easy to remove.

Level Technologies:
– ECHOTEL Ultrasonic Switch or Tuffy® II Float-Actuated Switch for point level
– ECLIPSE Guided Wave Radar Transmitter or PULSAR Non-Contact Radar Transmitter for continuous level
– ATLAS Magnetic Level Indicator for visual indication

Pulp & Paper Process Applications

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One Response to Level Instrumentation for Pulp and Paper Process Applications

  1. tina says:

    very useful article … got a deep idea about level measurement ..thanks for sharing..level measurement is very much important for plant safety
    Instrumentation

    Like

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