Environmental Features of Convective Lumber Drying

Abstract

Lumber drying is a mandatory technological operation that gives wood the properties necessary for the production of items, during which the wood is given shape and size stability during operation and/or increases biostability during transportation. Chamber drying is carried out at elevated temperatures, which predetermines the transfer of wood to a chemically active state. As a result, the first stage of extraction is realized – the release of a complex of substances in a solid, liquid and gaseous states onto the surface of the board. With all the variety of substances that accumulate during the growth process in each tree species, phenol and formaldehyde, which are common to all, are released during drying. They belong to class II hazard to humans. In the specialized literature, this issue is given unjustifiably little attention. The problem is complicated by the fact that a significant part of the wood drying production capacity is currently located within the urban area. Therefore, the entire spectrum of substances that are released from the dried wood is concentrated in the residential area, having a negative impact on humans. The aim of the research is to determine the degree of environmental impact of substances released from wood during drying. The list of substances that are released during convective drying from larch and pine wood, as well as data on the amount of these substances, which are given in the article, indicate the presence of an environmental pollution problem. In Russia, the entire volume of lumber for the production of products is dried in drying plants that do not have devices that neutralize pollutants. Consequently, harmful substances released from dried wood accumulate both on the territory of wood processing enterprises and in residential areas. From the above, it follows that drying lumber using low-temperature conditions cannot be considered an environmentally friendly type of production. This problem requires a more detailed study, which will allow us to develop a set of measures to reduce the negative impact of convective lumber drying on the environment.