OPTIMIZATION OF FLOCCULAR CLEANING AND DRAINAGE OF THIN DISPERSED SLUDGES
Abstract
The efficiency of solid phase retention and dehydration of finely dispersed products of a coal processing plant and a metallurgical enterprise on the module for cleaning and dewatering sludge is investigated. A technique for selecting the operating parameters of equipment based on the determination of the strength criterion of flocs is proposed. A methodology for technological tests has been developed to control the flocculation process and optimize the flow of flocculant depending on the concentration of the solid phase.
Industrial tests on the module for wastewater treatment and sludge dewatering using flocculants proved the effectiveness of the developed methodology. It is shown that the conditions for conducting tests on flocculation should correspond to the operating conditions of the circuit apparatus for cleaning and dewatering sludge. These conditions include sludge performance, sludge flow rate in the cross section of pipes and apparatuses, and the flow time from the flocculator to the centrifuge. During the testing of the Module, the solids retention efficiency of 97–99 % was achieved with the strength criteria of flocs in front of a centrifuge of 2–2.5 mm/s.
The conditions for the high efficiency of the apparatus chain are the optimization of the aggregation process itself. It is revealed that for the formation of strong flocs it is necessary to regulate the concentration of the solid phase. For coal sludge, the concentration of the solid phase before the flocculant is fed must be maintained no higher than 50–60 g/l, and for gas treatment sludge – no higher than 20–25 g/l. Correction of the concentration of sludge before the flocculator is possible by diluting it with clarified water to the optimum concentration for aggregation.
It is found that the moisture content of the sediment and the efficiency of the retention of the solid phase depend on the strength criterion of the flocs. Therefore, the optimization of the flocculant flow rate is possible by controlling and the residual floccule deposition rate after mechanical action in front of the dewatering equipment. The flocculant flow rate must be adjusted depending on the concentration of the solid phase in the sludge to achieve the desired criterion for the strength of the flocs
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Shevchenko, A. I., Bubnova, E. A. (2015). Perspektivy i problemy perevoda shlamonakopiteley Ukrainy v kategoriyu tehnogennyh mestorozhdeniy. Zbahachennia korysnykh kopalyn, 60, 162–169.
Wang, C., Harbottle, D., Liu, Q., Xu, Z. (2014). Current state of fine mineral tailings treatment: A critical review on theory and practice. Minerals Engineering, 58, 113–131. doi: https://doi.org/10.1016/j.mineng.2014.01.018
Sokur, A. K. (2012). Obzor gravitatsionnyh tehnologiy obogashcheniya ugol'nyh shlamov neflotatsionnoy krupnosti. Zbahachennia korysnykh kopalyn, 51 (92), 126–136.
Mohanty, M. K. (2007). Screen Bowl Centrifuge Dewatering Process: A Parameteric Study. Physical Separation in Science and Engineering, 2007, 1–9. doi: https://doi.org/10.1155/2007/70376
Tao, D., Parekh, B. K., Liu, J. T., Chen, S. (2003). An investigation on dewatering kinetics of ultrafine coal. International Journal of Mineral Processing, 70 (1-4), 235–249. doi: https://doi.org/10.1016/s0301-7516(03)00025-5
Murphy, C., Bennett, C., Olinger, G., Cousins, B. (2012). Operation of the belt filter presses at the rockspring development preparation plant. Corrxan. Availale at: http://www.corrxan.com/Coalprep_2012_Paper.pdf
Fan, Y., Dong, X., Li, H. (2015). Dewatering effect of fine coal slurry and filter cake structure based on particle characteristics. Vacuum, 114, 54–57. doi: https://doi.org/10.1016/j.vacuum.2015.01.003
Hou, Y., Dang, J., Wang, L., Yang, X., Wang, X. (2014). The Data Processing System of Coal Slurry Pipeline Pressure Based on AMFL. 2014 International Symposium on Computer, Consumer and Control. doi: https://doi.org/10.1109/is3c.2014.207
Reddy, K. R., Urbanek, A., Khodadoust, A. P. (2006). Electroosmotic dewatering of dredged sediments: Bench-scale investigation. Journal of Environmental Management, 78 (2), 200–208. doi: https://doi.org/10.1016/j.jenvman.2005.04.018
Xian-shu, D., Xiao-jie, H., Su-ling, Y., Wei-peng, R., Zhi-zhong, W. (2009). Vacuum filter and direct current electro-osmosis dewatering of fine coal slurry. Procedia Earth and Planetary Science, 1 (1), 685–693. doi: https://doi.org/10.1016/j.proeps.2009.09.108
Wu, Z. H., Hu, Y. J., Lee, D. J., Mujumdar, A. S., Li, Z. Y. (2010). Dewatering and Drying in Mineral Processing Industry: Potential for Innovation. Drying Technology, 28 (7), 834–842. doi: https://doi.org/10.1080/07373937.2010.490485
Ksenofontov, V. V., Makeev, I. I. (2014). Settling and Filtering Centrifuge for Dewatering of Coal Slack - Theory and Practice. Ugol', 12, 78–81.
Bethell, P. J. (2004). Froth Flotation – To Deslime or Not to Deslime? CPSA Journal, 3 (1), 12–15.
Parekh, B. K. (2009). Dewatering of fine coal and refuse slurries-problems and possibilities. Procedia Earth and Planetary Science, 1 (1), 621–626. doi: https://doi.org/10.1016/j.proeps.2009.09.098
Shkop, A., Tseitlin, M., Shestopalov, O., Raiko, V. (2017). Research of ways to reduce mechanical influence on floccules in a centrifuge. Technology Audit and Production Reserves, 1 (3 (33)), 39–45. doi: https://doi.org/10.15587/2312-8372.2017.93690
Oyegbile, B., Ay, P., Narra, S. (2016). Flocculation kinetics and hydrodynamic interactions in natural and engineered flow systems: A review. Environmental Engineering Research, 21 (1), 1–14. doi: https://doi.org/10.4491/eer.2015.086
Hogg, R. (2000). Flocculation and dewatering. International Journal of Mineral Processing, 58 (1-4), 223–236. doi: https://doi.org/10.1016/s0301-7516(99)00023-x
Shkop, A., Tseitlin, M., Shestopalov, O., Raiko, V. (2017). A study of the flocculs strength of polydisperse coal suspensions to mechanical influences. EUREKA: Physics and Engineering, 1, 13–20. doi: https://doi.org/10.21303/2461-4262.2017.00268
Shkop, A., Briankin, O., Shestopalov, O., Ponomareva, N. (2017). Investigation of the treatment efficiency of fine-dispersed slime of a water rotation cycle of a metallurgical enterprise. Technology Audit and Production Reserves, 5 (3 (37)), 22–29. doi: https://doi.org/10.15587/2312-8372.2017.112791
Shkop, A., Briankin, O., Shestopalov, O., Ponomareva, N. (2017). Investigation of flocculation efficiency in treatment of wet gas treatment slime of ferroalloys production. Technology Audit and Production Reserves, 5 (3 (37)), 29–39. doi: https://doi.org/10.15587/2312-8372.2017.112792
Wang, Y., Chen, K., Mo, L., Li, J., Xu, J. (2014). Optimization of coagulation–flocculation process for papermaking-reconstituted tobacco slice wastewater treatment using response surface methodology. Journal of Industrial and Engineering Chemistry, 20 (2), 391–396. doi: https://doi.org/10.1016/j.jiec.2013.04.033
Trinh, T. K., Kang, L. S. (2011). Response surface methodological approach to optimize the coagulation–flocculation process in drinking water treatment. Chemical Engineering Research and Design, 89 (7), 1126–1135. doi: https://doi.org/10.1016/j.cherd.2010.12.004
Copyright (c) 2020 Oleksii Shestopalov, Oleksandr Briankin, Nadegda Rykusova, Oksana Hetta, Valentina Raiko, Musii Tseitlin
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