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Lecturer(s)
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Potůček František, prof. Ing. CSc.
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Course content
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Pulp washing. Equilibrium. Kinetics of leaching. Basic principles of pulp washing. Commercial pulp washers. Washer performance parameters (dilution factor, wash liquor ratio, displacement ratio, washing efficiency, loss of solutes, Norden efficiency factor, modified Norden efficiency factor, equivalent displacement ratio). Cross-flow washing (local efficiency, number of transfer units). Stage-wise washing. Countercurrent washing. Calculation of the number of ideal washing stages. Washers in series without and with side streams. Evaporation of spent pulping liquors. Physical characteristics of liquors. Heat transfer (elevation in boiling point, hydrostatic head, conditions for boiling). Mass and heat balances. Heating surface. Steam consumption. Single-effect evaporator. Multiple-effect evaporators (forward feed, backward feed, mixed feed). Economy of multiple-effect evaporator. Gas absorption. Absorption without chemical reaction. Equilibrium (solubility). Non-isothermal absorption. Mass and heat balances of absorber. Absorption with recycling of strong liquor. Absorption with chemical reaction. Packed bed absorbers, floating bed absorbers, Venturi scrubbers (hydrodynamic behaviour, pressure drop, mass and heat transfer, height of bed of packing, diameter of absorber, number of scrubbers in series). Absorption of sulphur dioxide into water, into solution of sodium hydroxide, into solution of magnesium hydroxide and magnesium sulphite. Absorption of chlorine dioxide into water. Absorption of sulphur compounds into white liquor.
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Learning activities and teaching methods
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Monologic (reading, lecture, briefing)
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Learning outcomes
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Within the frame of this subject students learn to solve technological problems occurring at pulp production from a chemical engineering point of view, particularly to analyze given problem, to choose suitable calculation method, to formulate simplified assumption, as well as to evaluate the obtained results from an operating standpoint.
A graduate should be able to analyze some technological problems connected with pulp production and to find their solutions including economic and environmental aspects.
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Prerequisites
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Basic knowledge of chemical engineering.
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Assessment methods and criteria
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Oral examination, Written examination
The examination consists of a written test and an oral examination. The written test comprises two problems, one in pulp washing and one concerning evaporation or absorption.
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Recommended literature
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BRATČIKOV, G. G. Očistka gazovych vybrosov v celljulozno-bumažnoj promyšlennosti. Moskva: Lesnaja Promyšlennost, 1989..
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BUŠMELEV, V. A., VOLMAN, N. S., KOKUŠKIN, O. A. Processy i apparaty celljulozno-bumažnogo proizvodstva. Moskva: Lesnaja Promyšlennost, 1985..
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KEENEY, N. H., WALKINSHAW, J. W. A Chemical Engineering Workbook for Pulp and Paper Industry. Vol. 1, and 2. Atlanta: TAPPI, 1979..
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Potůček, František. Papírenské inženýrství I. Pardubice: Univerzita Pardubice, 2000. ISBN 80-7194-256-1.
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Potůček, František. Úvod k řešení příkladů z papírenského inženýrství. Pardubice: Univerzita Pardubice, 2002. ISBN 80-7194-430-0.
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