The goal of these courses is to help mill personnel run their mill more efficiently, with less unplanned downtime and with minimal capital purchases. Please contact us for more information about these courses.

Plugging of White Liquor and Weak Wash Pressure Filters – Causes and Prevention

Tubular backpulse pressure filters are commonly used in Kraft mills for clarification of white liquor and weak wash. Unscheduled filter replacement due to plugging is a significant expense and may result in mill downtime. Acid washing of filters is commonly used but is not always effective. The goal of this course is to reduce the frequency of filter acid washes and to significantly reduce unscheduled filter replacement.

This course looks at the factors that can lead to increased pressure drop and plugging in pressure filters and options for prevention. The course is based on completed mill projects aimed at understanding filter plugging mechanisms and optimizing cleaning procedures. I published the only information on this topic available in the technical literature (Taylor et al., 2008, 2011). Read More

Purchased Lime Quality Control – Understand the Chemical and Physical Properties of Purchased Lime to Improve Mill Efficiency

Variation in the quality of purchased lime has led to serious process disruptions and shutdowns at many mills. Problems have centered on poor causticizing, increased plugging of white liquor pressure filters, decrease in lime mud solids content, and increased lime kiln ring formation. Lime purity requirements for Kraft mills are much higher than required by other commercial users. This is because non-process element impurities accumulate in the lime cycle of a Kraft mill (McGuffie and Taylor, 2007). Previous work has shown that increased levels of clays, iron and magnesium in purchased lime and limestone have resulted in process disruption (Taylor et al., 2008). Read More

Understand the Behaviour and Properties of Non-Process Elements and Compounds to Improve Mill Efficiency

The accumulation of non-process elements (NPEs) in Kraft mill process streams is becoming increasingly important as mills move toward effluent system closure. The effects of NPEs on Kraft mill operation include increased lime kiln fuel use, reduced lime mud settling rates, reduced mud filtration efficiency, and increased scaling of heat exchangers.
This course looks at the behavior and properties of NPEs and NPE compounds and how they can affect mill operation. This course is based on successful mill projects along with a review of the technical literature. Read More

Chemistry of Lime Kiln Wet Scrubbers - Improve Operation and Reduce Scaling

Wet scrubbers are used at some Kraft mills to reduce particulate emissions from the lime kiln. Some of these mills experience serious scaling problems in the scrubber system. In some cases, this scaling has caused mill shutdowns from kiln shutdown and insufficient lime production.

The chemistry of lime kiln wet scrubbers is very similar to that of flue gas desulphurization (FGD) scrubbers used in power generation. A large amount of literature is available on FGD chemistry, while very little is published on lime kiln wet scrubbers. This course is based on a review of the technical literature and on work carried out on kiln scrubbers in Canada and the U.S. Read More

Biocides for Slime Control - An Unbiased Review of Oxidizing and Non-Oxidizing Biocides used in White Water Systems

Biocides are commonly used to control the growth of micro-organisms in mill white water systems. Competing suppliers provide a wide range of trade-name products that vary significantly in cost and claimed performance.

This course provides an unbiased look at the chemicals available for slime control in white water systems. Specific characteristics and pros/cons of each biocide option are discussed. Read More