Category Archive: Chemical Products

What You Need to Know About Brown Stock Washing Defoamers

Brown stock washing is a complex, dynamic process in which dirty wash water or weak black liquor (dissolved organic and inorganic material obtained from the pulp cooking process) is separated from the pulp fibers1. The organic materials are recovered for their fuel value and the inorganic material is recovered for the sodium content to regenerate NaOH.

Under-designed capital equipment can be augmented using chemical enhancements. In the case of brownstock washers, the application of defoamer is required to improve mat drainage and to control foam to enable overloaded washers to wash efficiently; this also allows pulp from the digesters to flow continuously to the bleach plant and/or the paper machine.2

Washing efficiency directly correlates to pulp cleanliness. Cleaner pulp results in better chemical recovery, lower bleaching costs, fewer deposition issues, and more consistent pulp is sent to the paper machine.

The following article provides an overview of brown stock washing deformers, outlining how they work, key benefits, and the types available.

How Do Brown Stock Washing Defoamers Work?

Brown stock washing defoamers have two purposes. First is to control the foam and prevent vats from overflowing onto the floor causing loss of product (the pulp) and housekeeping issues, while providing drainage on the washers which provides cleaner pulp and improves washing efficiency.

Second is to recover valuable spent liquor. The black liquor is recovered for the fuel value and to regenerate NaOH by recovering sodium from the washing process.

The foam level in the vat is not an indication of how well the defoamer is performing. If the foam is not spilling over on to the floor it is then purely cosmetic. The real indication of the defoamer’s performance is how well the foam is being released from the fiber. When the foam is released from the fiber it allows drainage.

It is important to understand the defoamer must have a positive Entry Coefficient and a positive Spreading Coefficient. These are expressed in the following equations:

(Entry Coefficient) E = γw/a + γw/o – γo/a

Where γ is the surface tension or interfacial tension in dynes/cm2

(Spreading Coefficient) S = γw/a – γw/o – γo/a

Where “w” is water, “o” is oil, and “a” is air

Brown Stock Washer Defoamers

The equations briefly explained:

The Entry Coefficient is equal to the surface tension of the black liquor + the interfacial tension between liquor and oil (i.e. the defoamer), minus the surface tension of the oil. This allows the defoamer droplet to enter the monolayer at the air/water interface.

The same is true for the Spreading Coefficient: black liquor – the interfacial tension between liquor and oil, minus the surface tension of the oil. This causes the defoamer droplet to spread along the air/water interface forming a defoamer “lens.”

How defoamers workHydrophobic particles within the defoamer facilitate the entering of the oil droplet into the surfactant monolayer at the air/water interface. With a positive Entry Coefficient, the defoamer droplet enters the surfactant monolayer at the air/water interface. Once the droplet is there, the positive Spreading Coefficient allows the defoamer droplet to spread across the monolayer forming a lens. The shape of the lens is altered by the movements in the foam. Stress occurs until the lens breaks and the foam lamella ruptures. This results in foam control throughout the pulp mill.

On fiber, larger and larger bubbles are formed until the buoyancy of the bubble overcomes its adherence to the fiber and floats away from the fiber. The foam on the fiber causes an apparent increase in the fiber’s size. As the foam is removed from the fiber the apparent fiber size decreases creating a shorter path for the water to travel through the mat. The shorter path for the water results in improved drainage.

It should be noted, when using defoamers in brown stock washing operations, it is important to understand that the defoamer must perform a balancing act, where the defoamer is sufficiently compatible in the black liquor to not cause deposition, yet incompatible (insoluble) enough to perform efficiently on the washer. A defoamer is never soluble in the medium it is defoaming.

Benefits of Brown Stock Washing Defoamers

A good defoamer program should facilitate production of the pulp, and add economic value to the pulp mill process by addressing the following:

  • Housekeeping issues
  • Increased chemical recovery
  • Reduced energy costs
  • Lower bleaching costs
  • The reduction of the environmental impact of the mill
  • Fewer safety hazards
  • Increased production rates
  • Increased quality of the end product
  • Lower reject rates3

Types of Defoamers for Brown Stock Washing Operations

Pulp and Paper MillBrown stock washing defoamers come in a variety of formulas and strengths to suit the needs of different pulp and paper processes. The types available include:

  • Oil-based defoamers
  • Water-extended, oil-based defoamers
  • Concentrated or water-based silicone defoamers
  • Polymer-based defoamers

Oil-based and water-extended oil-based defoamers are less common than they were 15 to 20 years ago. They are used primarily in mills where silicone and/or silicates are not allowed.

Brown Stock Washing Defoamer Solutions From AMS

Brown stock washing defoamers are essential to both product and process quality. As a leading manufacturer and supplier of foam control products, Applied Materials Solutions has an extensive range of products suitable for use in these pulping applications. Our product offerings include:

  • Water-based silicone defoamers: (e.g. TRANS-2994 and TRANS-2931)
  • Oil-based defoamers: (e.g. TRANS-7285 and TRANS-7115)

For additional information about our brown stock washing defoamers and other product solutions, contact us today.



Brownstock washing – A review of the literature, TAPPI Journal January 2014, Ricardo B. Santos and Peter W. Hart; page 9

Brownstock Washing – Practices and Fundamentals. TAPPI Press, Peter Hart and Michael Brown, Chapter 15, page 545

Brownstock Washing – Practices and Fundamentals. TAPPI Press, Peter Hart and Michael Brown, Chapter 15, page 562


All About Hydrophobic Treated Silica Products

Applied Material Solutions (AMS) is a Wisconsin-based company that manufactures high-quality hydrophobic treated silica products, including both precipitated and fumed varieties. By leveraging our unique range of manufacturing capabilities, our expert team produces a wide range of silica products for use in a diverse set of industries.

The following blog post provides an overview of hydrophobic treated silica products, outlining the chemical properties, applications, and solutions available from AMS.

Chemical Properties of Hydrophobic Treated Silica

Hydrophobic Treated SIlica

In addition to its hydrophobic—i.e., water-repelling—properties, treated silica demonstrates several characteristics that make it well-suited for use in a wide range of applications. As an ingredient in other materials and products, it offers the following benefits:

  • Foam control. It serves as a key active ingredient in many foam control products, such as antifoaming agents, defoamers, and deaerators.
  • Powder free flow encouragement. It facilitates the free flow of powdered substances that have a tendency to “cake” or clump together. It also enhances their storage stability.
  • Processing improvements. The utilization of treated silica allows for optimal processability, hydrophobicity control, thickening, thixotropy, rheology control, and suspension and stability behavior. For example, motionless particles can be restored to their original level of viscosity with a minimum expenditure of energy.
  • Adsorbent qualities. It can adsorb compounds in gaseous, liquid, or solid states and act as a carrier that allows for the conversion of liquids and pastes into powders.
  • Anti-blocking, anti-sagging, anti-setting, and anti-setoff attributes. An example of an application in which these qualities are critical is in anti-setoff spray powder, which industry professionals use to maintain an air gap between printed sheets of paper to prevent ink bleed-through.
  • Mechanical improvements. It can improve tensile strength, elongation at break, and tear resistance and help minimize the effect of temperature on mechanical properties.
  • When used in materials, such as polymers, it reinforces both strength and structure.
  • Pigment stabilization and dispersion. It can prevent or delay the sedimentation of solids in liquid systems, as well as disperse sediments that have already settled, break down solid particles, and stop such particles from recombining.
  • Print definition enhancements. The resolution and print quality of toners can be significantly improved through the use of hydrophobic treated silica.
  • Thermal insulation. Amorphous silicon dioxide is a highly non-conductive material, making it an excellent choice for thermal insulation applications.

Common Applications of Hydrophobic Treated Silica

Hydrophobic treated silica finds application in a variety of materials and products. Some of its most common uses include:

  • Defoamers and antifoams
  • Demulsifiers
  • Fire extinguishers
  • Silicone rubber
  • Silicone sealants
  • Greases
  • Paints and coatings
  • Plastics
  • Polyester resins
  • Cosmetics
  • Inks and toners

Hydrophobic Treated Silica Solutions From AMS

At AMS, we manufacture treated silica products for a myriad of customer applications. Armed with years of silica treatment manufacturing experience and a modern manufacturing facility, our team can produce an array of products across a wide range of particle sizes, hydrophobicity levels, and surface areas to suit our customers’ needs.

From development to production to testing and regulation, AMS strives to meet the requirements outlined by our customers and to provide the highest level of quality, accuracy, and performance. In doing so, we aim to minimize customer investment—both in regard to time and money—and maximize customer satisfaction.

For additional information about our treated silica solutions, contact us today.

How it Works: Corn Oil Demulsifiers

Corn oil plays a central role in maintaining the profitability of today’s fuel ethanol facilities. Corn oil demulsifiers serve to improve oil release during the mechanical extraction process, resulting in significantly increased corn oil yields. Those improved yields translate to higher profits.

Corn oil demulsifiers also cut down on solids present in corn oil and create cleaner, higher-quality oil. Decreased levels of system deposition also translate to less downtime spent maintaining or cleaning said systems.

How They Work

Corn Oil Demulsifier

Corn oil demulsifiers aim to break the emulsion between the water and oil components of the corn oil. When demulsifying agents are dosed, they begin to interfere with the stability of the emulsion. This causes oil droplets to shift around and join together into larger droplets. These larger droplets of corn oil are much easier to separate and capture through the centrifugation process.

Extraction aids like corn oil demulsifiers can also improve the release of corn oil during centrifugation. Their benefits extend beyond the initial dosing period, as well. Demulsifiers modify surface chemistry within the syrup and allow oil to be released more easily, which means that it takes less centrifugal energy to separate the oil from the surface. The result of this process is increased corn oil production and notably cleaner corn oil.

Benefits of Demulsifiers

Corn oil demulsifiers confer a wide array of advantages and AMS’s additives normally result in the following improvements:

  • Decreased demulsifier feed rates
  • Reduced demulsifier costs
  • Higher corn oil yields
  • Superior corn oil quality
  • Reduced presence of solids in produced oil
  • Improved profit margins
  • Effectiveness in a broad range of operating conditions

Applied Material Solutions

At Applied Material Solutions, we produce an array of corn oil separation aids and demulsifiers. We also regularly customize our products to align with the individual needs of each plant’s conditions. Our customizable product line includes:

  • AMulSion COD-A
  • AMulSion COD-G
  • AMulSion COD-J

For more information about our selection of corn oil demulsifiers or capabilities, please don’t hesitate to contact our team today to learn how AMS can help improve your corn oil production.