Fluid Analysis And Experimental Study On Flotation Deinking

Flotation deinking is the core technology of recycled paper pulping,but also the bottleneck that restricts recycled paper to become the raw materials of bleached paper and paperboard products.Therefore,the development of flotation deinking technology,as well as flotation deinking equipment and system optimization,is conducive to expanding the scope of application of recycled paper as raw materials,in a greater degree of replacing wood pulp,so as to protect human survival environment and promote the harmonious development of man and nature.Based on the two types of horizontal flotation cells,the flow condition of the fluid in the flotation cell with different structures was simulated and analyzed by means of CFD software Fluent,and the flotation cell with better structure was optimized,by adding spoiler to optimize the fluid flow condition,and achieved a more satisfactory results.The fluid simulation method was used to analyze the effect of pressure on the fluid flow,and the optimal inlet pressure was obtained,which provided the basis for the equipment selection calculation.In order to investigate the effect of flotation deinking system on flotation performance,the mathematical models of two continuous flotation systems were established,and the outer-flow mathematical model was validated by pilot test.The influence of raw material and flotation consistency on the flotation performance was analyzed experimentally.The experimental results show that the floatability of different raw materials is very different.The consistency contrast experiment can gave input for the selection of reasonable design consistency,so as to select the appropriate equipment.The consistency contrast analysis results can also provide reference for consistency optimization in mill commissioning phase.The results of flotation deinking fluid analysis,mathematical model analysis and experimental analysis were applied to a deinking line upgrade project which Voith provided for a domestic paper mill.An appropriate structure of flotation cells was selected according to the results of fluid analysis.An appropriate flotation deinking system was designed according to the mathematical model analysis.The appropriate equipment sizes were selected based on the experimental data and the said analysis.According to the mill data,the total brightness increment of the pulp in the two-stage flotation deinking system was 15.8% ISO,which achieved the expected effect,which verifies the feasibility of this study.