Research On Process Of Positive-pressure Horizontal Filtration And Research On Its New Equipment

Dehydration of fine-grained materials was widely used in various industries. Technology in terms of dehydration of fine-grained materials are mostly still in the laboratory research and some empirical or semi-empirical formulas. In terms of equipment and technology on dehydration of fine-grained materials, there are some gaps and imperfections in structure, energy consumption, automation, equipment maintenance capacity etc. Under the guidance of empirical and semi-empirical formulas and combined with the actual situation of production site, it is more meaningful to design and develop new equipment for fine-grained materials dehydration with independent intellectual property rights.This research has a detailed analysis of the problems incurred during the fine-grained material dewatering process and serious revelations about the advantages and disadvantages of various types of equipment using filtration technologies This paper reviews the theories of centrifugal dewatering and dehydration theory based on a general filter differential equations by Ruth and others and explains the actual experience of the use of these theories in industrial production. The author deducted empirical formula of pressure filtration on basis of Park Su-Ye formula and then designed the positive-pressure filtration devices at the horizontality of filter medium. In order to fully explain the characteristics and advantages of positive-pressure filtration, interference settlement and its effect of grain size, capillary dehydration heavy particle retention and barometric pressure dehydration mechanisms were introduced in the discourse of the theory, which explains the filter cake structure by positive-pressure filtration and the "air drainage" mechanism more in-depth and provide strong technical support for research and development of positive-pressure filtration devices.This research confirmed positive-pressure filtration hindered settling's effect under different conditions and the rejection of the role of coarse particle through stratified slice method to positive-pressure horizontal filter cake. Using the way of areal sampling to positive-pressure horizontal filter cake, process of"drainage by gas"was verified, and technical support was provided for researching on positive-pressure filtration equipment.Under the guidance of the past experience and the semi-empirical formula and by means of the national standards, this research measured the density, the viscosity of filtrate, cake specific resistance, filter cake compressibility and other contents, and contacted with positive-pressure filtration theory. The paper compared the specific resistances and structures of filter cakes respectively by mechanical filtration and positive-pressure filtration. The results showed the constructional advantages and lower resistivity of filter cakes by positive-pressure horizontal filtration, provided a premise for the research on Positive-pressure horizontal filtration. On this basis, paper investigated filter materials in single parameter change about different pressure, concentration and gradation composition effect on process of Positive-pressure horizontal filtration, and discussed reciprocal action of various factors. The results showed that no interaction was found between three factors. The more the material concentration and filtration pressure were higher, the more filter mass moisture was lower and treatment capacity was larger. The paper confirmed that the structural features of filter mass consistent with computer simulation result by industrial test.The research compared positive-pressure filtration, pressure filtration and horizontal belt vacuum filtration, discussed positive-pressure filter cake's feature and compared with the filter cake's structure using currently filtering technology. Differences in application of filtration theory, the working principle and filtering results were analyzed. Advantages of positive-pressure filtration dewatering devices can be summarized.Meanwhile, the paper pointed out that there is still much work to be done for industrial application of positive-pressure filtration equipment. The choice of the filter cloth and the design of equipment's structure strength have to further improving.There are 72 figures, 93tables, 135 references in this paper.