Pulp Mill Bubble-Up

Pulp mill process piping can be a critical production challenge and may be susceptible to deposition because of temperature, concentration and turbidity changes in process liquor.

Carbonate based scales typically found in white liquor, weak wash, green liquor and lime mud slurry lines can result in decreased flow rates, which in turn impacts efficiency and performance of the kraft recovery cycle. Scale deposits not only affect efficiency, they create conditions for under-deposit corrosion attack. Extreme scale conditions can limit white liquor production at mills, and negatively impact pulp production. Historically, kraft mills have utilized numerous methods to keep liquor line scale problems under control (high pressure washing, scale inhibition products, magnetic antiscale, etc.).

The DuBois Bubble-Up® process utilizes acidic based foam to chemically dissolve inorganic scales typically found in kraft mill process liquor lines. The Bubble-Up® is a highly effective and cost efficient method of delivering high strength cleaning solutions to inaccessible areas process lines without invasive maintenance.

Benefits of the DuBois Pulp Mill BubbleUp® Program:

• Less time consuming than high pressure washing
• Less expensive than scale inhibition
• Typically can be completed at the same or lower cost than pressure washing
• In-line flow increases from 22%-900% have been acheived

The Bubble-Up® Procedure

The procedure consists of pumping a concentrated DuBois cleaner into the process piping and then agitating it with air, causing the bubbling action to occur.

Application points include:

• Digester white liquor lines
• Dissolving tank feed and discharge piping
• Green liquor lines
• Lime mud slurry lines
• Green liquor tank feed and discharge piping
• Stripper columns
• Evaporator trains
• Digester liquor heaters
• Green liquor heat exchangers

To facilitate the boilout and/or Bubble-Up® procedure, DuBois supplies a portable Bubble-Up® cart designed to safely and easily transfer DuBois products to the optimum application point.

The scouring action of the bubbles contacts the entire circumference of the piping and sweeps away the deposits. The result is improved cleaning in less time than conventional methods!