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Microwave assisted barking of frozen wood
Author(s) -
Gilbert Allan F.,
Turcotte Camille
Publication year - 1994
Publication title -
the canadian journal of chemical engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.404
H-Index - 67
eISSN - 1939-019X
pISSN - 0008-4034
DOI - 10.1002/cjce.5450720519
Subject(s) - pulpwood , bark (sound) , tonne , moisture , environmental science , veneer , pulp and paper industry , capital cost , engineering , waste management , forestry , materials science , composite material , geography , electrical engineering
Thawing pulpwood with microwave energy could be an effective means to improve winter barking operations in Canadian interior mills. Complete bark thawing requires 140 MJ per tonne of wood for average 25 cm diameter logs at 90 mass % moisture, dry basis. However, complete thawing may not be necessary, as warming both spruce and aspen bark from −20°C to −5°C, decreases the bark/wood bond strength from 2.5–4.5 MPa to room temperature values of 0.5–1.5 MPa. This improves the economics of winter operation, but the expenditure for capital which has no year‐round use is not easily justified. Also the design of safe large‐scale microwave generators and applicators remains a technical challenge.