A challenge in using recycled material in the papermaking process is the presence of hydrophobic organics with adhesive properties commonly known as stickies. Hydrophobic agglomerates can result in spots or defects in the final paper product or deposit on papermaking equipment resulting in poor runnability and downtime. Technologies for monitoring and controlling microstickies exist. However, a need exists for a technique to rapidly determine the size and content of macrostickies (diameter>100 microns) in recycled pulp process streams. The present invention is a device and method to perform real-time macrostickies and/or any visible hydrophobic particle analysis in an aqueous medium. Using the present invention, furnish quality can be monitored and treatment performance can be monitored and controlled. The technique is based on fluorescence image analysis to identify and count sticky particles as well as measure their size.

In a starch concentration measurement, a liquid sample is conducted from a liquid sample such as pulp suspension or filtrate of a paper, board or tissue process. An iodine solution is added to the sample, and a light absorbance or transmittance of the sample is measured at a wavelength longer than about 650 nm, for example longer than about 700 nm. The measured absorbance or transmittance of the sample is converted into the starch concentration of the sample by a predefined correlation between a starch concentration and a light absorbance or transmittance.

A fiber processing system includes a fiber processing unit having an inlet, accepts outlet, and solid discharge outlet and configured to remove solid contaminants from a fiber-containing stream to produce an accepts stream exiting the accepts outlet and a solid discharge stream exiting the solid discharge outlet. The fiber processing system includes an optical system having an imaging device and image processing system. The imaging device is configured to capture images of the solid discharge stream at or downstream of the solid discharge outlet, and the image processing system is configured to determine relative fiber content, a relative generation rate, types of materials in, or combinations thereof of the solid discharge stream from the captured images. The fiber content, generation rate, and/or types of materials of the solid discharge stream are used to control operation of the fiber processing system or other upstream pulp processing equipment.