Study On Working Process Of Low And Medium Consistency Refining Based On High-speed Photography Technology And Photography Technology

The paper industry is a traditional industry which gets larger and larger. Refining as animportant section of the papermaking process, there is great potential in the optimization ofenergy-saving and raw materials. Therefore, the study of the refining process occupies acrucial position in the paper industry. The refining can be divided into low consistencyrefining and mid-consistency refining, and between the two there is a considerable differencein the mode of action and pulp types of adaptation. Refining process has been studied athome and abroad, the refining process also raised a lot of theory. These theories have playedan important role in guiding refiner design. However, there are differences in refiner ways, itsmode of action and mechanism. It is necessary to in-depth understanding of the occurrence ofthe process of refining, pulp fibers in silk fibrillation process and motion trajectory, which isa significant role for improving the quality of refiner. Refining mechanism clarified toprovide directional guidance and technical support for the improvement of the refiningprocess.Since the nineties, CCD imaging technology has been developed rapidly. The high-speedcamera is a technology developed from the high-speed continuous image acquisition devices.The development of high-speed photography technology has brought tremendous promotionand impact to scientific research.The core of this paper is to use the high-speed camera technology to study medium andlow consistency refining process visualization, intuitive experimental data obtained byshooting the refining process. After analysis and processing, it can provide further guidancetheoretical development and practical application. The main contents include:（1） Developed a set of experimental apparatus which can be used to do some visualresearch on refining.（2） The High-speed camera shooting records changes in organic grinding internalfiber tracer in the mill film splitting process, the trajectory can be clearly observed.（3） The Pulp fibers are colored by the direct dye. The thermal stability, beatingperformance, fiber morphology, paper-making performance and contaminationresistance of the fibers after dyeing are tested.（4） Use MATLAB processing captured image, the image processing part of the de-noising, filtering visual image optimization. Using MATLAB different images onthe same fiber tracer superimposed in the same image, and calculating the distancebetween them, the quantitative calculation of fluid shear stress as possible.（5） Described the trajectory of the fiber tracer in the medium and low consistencyrefining process. By analyzing the reasons for the various phenomena in the refiningprocess, combined the theoretical and refined experimental phenomena, describedlow-consistency refining process differences. The possible trajectory of the fibertracer on image processing and experimental corroboration of the phenomenon, andquantitatively calculate the fiber tracer fluid shear stress suffered the size ofmid-consistency and low-consistency refining process.Through the work of this paper, the following are conclusions:（1） The pulp fibers used direct dye on the thermal stability in paper-makingtemperature is completely the same. And pulp staining direct dye beating trends issame, but beating degree will be slightly less than the undyed pulp. Compared withthe physical form of dyed pulp fibers and non-transfected pulp slightly longer thanits length, and the width are bigger, the the crimp index kink index is relativelybigger. Direct dyes pulp, paper quality basic consistent with pulp tensile index isslightly smaller than the undyed pulp, and the tear will be slightly larger than theundyed pulp. Observed through a microscope, the mechanism of direct dyes in thepulp fibers, primarily occurring in a given area of the cell walls and fiber, dyes andfixative wrapped in the fiber cells of the external. Fibers after dyeing, color fastnessis very good, not contaminated with no dye slurry. Direct dyes the fiber can beapplied to the fiber tracer studies, and can be combined with a high-speed cameratechnology to study the beating process.（2） The high-speed camera technology studied refining process detailedobservations. Low-consistency refining process, the fibers are into the group in theform of the presence of less than water. However, the size and thickness of the innerand outer loops of the fiber agglomerations difference exists. Outer loop of thegrinding teeth of the blade slurry layer thickness is thinner, the fiber agglomerationssmaller the more uniform distribution. Mid-consistency refining process, the trenchfiber group speed is very slow, fiber groups are larger, it is closer to the solid-state. Its force comes mainly from the after threads pulp driven. Between static anddynamic disks, the pulp is not always filled with the gap. And in different areasthere will form a series of holes of different sizes.（3） The use of high-speed camera technology, low-consistency and mid-consistencyrefining in the same grinding teeth phenomenon were observed. Low-consistencyrefining process in the inner loop, Barely saw the clusters of fibers exist in grindingteeth, and it is apparent that the presence of water. Concentrated in the inner ringteeth of pulp layer is very thick. And the large group of fibers as the main form ofstripping, see less than the presence of water. The med-consistency refiner in thisstate, suffered mechanical shearing force will be evenly distributed to a plurality ofsmall fibers, reduce the mechanical shear force directly on the fiber cut off. Inlow-consistency refining process in the outer loop, the low-concentration of slurryflow through grinding teeth in a more continuous manner, their morphologychanged little. While concentrated slurry flow through the grinding teeth in acontinuous way, there is a greater changes in the morphology of the fiber group,fiber group can be seen in this period a larger force acted.（4） Using Matlab the fiber tracer position and velocity in the low-consistencyrefining process were calculated. Found in the concentration of refining thefiber-group average fluid shear stress to4.43×10^-3N low consistency refining fluidshear force of1.84×10^-3N. The proportion of fluid shear stress is greater than thelow consistency refining consistency refining process.