Kinetika konvekcijskega sušenja lesnih sekancev

diplomsko delo

Rok Atelšek (Author), Željko Gorišek (Reviewer), Aleš Straže (Mentor), Dominika Gornik Bučar (Co-mentor)

Abstract

V diplomski nalogi smo proučevali kinetiko sušenja lesnih sekancev treh domačih lesnih vrst, bukve, breze in smreke, z upoštevanjem dveh različnih velikostih razredov P16 in P31,5. Stacionarno konvekcijsko sušenje sekancev smo izvedli v laboratorijskem sušilnem kanalu z variiranjem temperature sušenja med 40 °C in 80 °C, ter pri hitrosti gibanja zraka v razponu med 1 m/s in 3 m/s. Sušenje smo spremljali z intervalnim tehtanjem nasutja sekancev debeline 1,5 cm, 3 cm in 5 cm , od koder smo izračunali karakteristične čase sušenja, koeficiente difuzivnosti v nasutju sekancev ter koeficiente snovne prestopnosti. V splošnem je najhitreje potekalo sušenje smrekovih sekancev, najpočasneje pa sušenje bukovih sekancev. Hitrost sušenja se je povečevala z višanjem temperature in hitrosti gibanja zraka, ter z manjšanjem debeline nasutja sekancev . Pri vseh pogojih sušenja, vseh drevesnih vrstah ter pri obeh velikostnih razredih smo ugotovili prevladujoč zunanji snovni upor. Koeficienti snovne prestopnosti in koeficienti difuzivnosti so v splošnem naraščali z dviganjem temperature sušenja in večanjem hitrosti gibanja zraka.

Keywords

les;sušenje lesa;lesni sekanci;temperatura;hitrost gibanja zraka;kinetika sušenja;snovni upor;

Data

Language:	Slovenian
Year of publishing:	2017
Typology:	2.11 - Undergraduate Thesis
Organization:	UL BF - Biotechnical Faculty
Publisher:	[R. Atelšek]
UDC:	674.047
COBISS:	2771849
Views:	1131
Downloads:	633
Average score:	0 (0 votes)
Metadata:

Other data

Secondary language:	English
Secondary title:	Kinetics of convective drying of wood chips
Secondary abstract:	We studied the drying kinetics of wood chips of three domestic wood species, beech, birch and spruce, taking into account two different chips size classes P16 and P31.5. Stationary convective drying of wood chips was carried out in the laboratory drying tunnel at varying temperature between 40 °C and 80 °C, and the air velocity in the range between 1 m/s and 3 m/s. Drying process of 1.5 cm, 3 cm and 5 cm chips layer was monitored gravimetrically, on the basis of which we calculate the time constant, diffusion coefficient in the chips layer and convection mass transfer coefficient. Generally, the fastest drying was at spruce chips, and the slowest was drying of beach chips. Drying rate increased with the raising of temperature and the air velocity, and decreased with thickness of the chips layer. The prevailing external mass transfer resistance was determined at all drying conditions, in all wood species and all size classes of chips. Convection mass transfer coefficient and diffusion coefficient generally increased with increasing of drying temperature and air velocity.
Secondary keywords:	wood;drying;wood chips;temperature;air velocity;drying kinetics;mass transfer resistance;
Type (COBISS):	Bachelor thesis/paper
Study programme:	0
Thesis comment:	Univ. v Ljubljani, Biotehniška fak., Oddelek za lesarstvo
Pages:	X, 38 f., [3] f. pril.
ID:	10841597