Green liquor is the dissolved concentrations of sodium sulfide, sodium carbonate, and other substances from the paper-making process's recovery boiler. Measuring its density is an essential aspect of paper production quality.
The Electron Machine MPR EScan is used to measure the green liquor dissolved density, or TTA, at two different points in the process: after the green liquor dissolving tank and after the green liquor clarifier. With the refractometer sensing head positioned directly in the primary process lines, inline measurement enables real-time management of green liquor dilution to meet target TTA set-points. Excessive green liquid density and the accompanying harmful imminent crystallization within the dissolving tank are also indicated (and prevented) by the measurement.
One considerable challenge is sensor head scaling associated with green liquor. An optical coating forms on the refractometer sensing head. The coating must be dealt with efficiently and quickly to maintain the accuracy and with minimum maintenance. This is key for the refractometer's ability to provide an acceptable measurement cycle and duration. The maintenance necessary to keep the cleaning system running efficiently is challenging.
Controlling scaling is optimal when the variance of green liquor solids is reduced by automatically adjusting weak-wash dilution with the MPR E-Scan refractometer. Additionally, pressurized water, heated to the process temperature, rinses the refractometer optical components effectively, resulting in a further scaling reduction. The end outcome is advantageous for both control and acceptable maintenance scheduling.
By limiting thermal changes, minimizing maintenance, and providing a dependable measurement source for automatic inline control, refractometers with accompanying heated high-pressure water cleaning systems deliver excellent results in improving green liquor processing.
Visit www.electronmachine.com or contact 352-669-3101 for more information.
