Experimental Study of Pulp Washing Process

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UDС

661.728.2

DOI:

10.17238/issn0536-1036.2015.5.183

Abstract

The process of pulp washing by sulfite liquor displacement in batch cooking digester was studied. Filtrating constants and filtration rate depending on filtering layer depth and excess pressure for large-scale batch digesters were computed. It was shown that dry solids extrac-tion (soluble matter) from pulp fibers flow in two stages. The first stage – in out-diffusive area, while the second went on in internal diffusive area. It was showed that a depth of pulp layer at the end of displacement washing in cooking digesters of 320 m3capacity could reach up to 5,4 m in case of upward flow. The filtrating constants were calculated. It was found a relationship between filtration rate and hydraulic pressure at pulp washing in the cooking digesters equipped with hydraulic distributor for washing liquor. It was shown that at a certain hydraulic pressure in cooking digester a filtration rate of liquor might be constant till 120-th minute. High temperature pulp washing in batch cooking digesters enables producing easy-bleachable pulp.

Authors

M.I. Kravchenko, Candidate of Engineering, Associate Professor

Affiliation

Saint Petersburg State Forest Technical University under name of S.M. Kirov, Institutskiy per., 5, St. Petersburg, 194021, Russia; e-mail: ola.ola07@mail.ru

Keywords

mathematical model, pulping, washing, pulp bleaching, filtration, washing con-stants, cooking digester, pulp hardness, filtrating constants, filtration rate, engineering regu-lations, efficiency, hydraulic distributors of washing liquor.

References

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