Mathematical Model of the Pressing Process of Thermally-Modified Tree Bark in the Drum-Type Press-Granulators

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UDС

UDС 674.08

DOI:

10.17238/issn0536-1036.2017.2.130

Abstract

The involving tendency of wood waste as an environmentally friendly fuel in heat and power balance, emerging in the world and domestic practices, is becoming increasingly important. The timber industry enterprises produce large amounts of waste wood, 10...15 % of which is the tree bark. The most promising method of the use of this renewable energy resource is the wood pellets production. The process of pellets obtaining from stem wood is well developed, but their production from bark involves some technical difficulties (dehydration and bark disintegration, ground bark pressing through the cylindrical matrix nozzles of the roll-type press-granulators). The initial heat treatment of bark (thermal modification) solves the problems of its dehydration and mechanical disintegration to the constant consistency for further granulation. The theoretically grounded mathematical model describing the pressing process of disintegrating wood in the roll-type press-granulators with a cylindrical
matrix, which could optimize the design and technical and energy pressing parameters,
is not developed in the world and national literature. The goal of research is to develop
a mathematical model of the pressing process of thermally-modified tree bark, which would allow determining the connection of design parameters of a pressing component and the required qualities of wood pellets with the energy consumption in the roll-type pressgranulators with a cylindrical matrix. The technological pressing process from bark in the convergent film between the inner perforated cylindrical surface of a matrix and the outer cylindrical surface of a pressing roller is considered; the physical processes in the areas of pellet forming and ejecting from a nozzle are analyzed. We obtained a reasonable mathematical model of the charge pressing process from bark through a cylindrical matrix as well as the dependencies connecting the energy expended to drive the press-granulator with the design parameters of a pressing component and the charge physical and technological parameters from bark.

Authors

O.D. Myuller, Doctor of Engineering Sciences, Associate Professor V.I. Melekhov, Doctor of Engineering Sciences, Professor N.G. Ponomareva, Postgraduate Student T.V. Tyurikova, Master M.O. Khrustaleva, Engineer

Affiliation

Northern (Arctic) Federal University named after M.V. Lomonosov, NaberezhnayaSevernoy Dviny, 17, Arkhangelsk, 163002, Russian Federation; e-mail: ockar@mail.ru,n.ponomareva@narfu.ru

Keywords

thermally-modified tree bark, press-granulator, matrix, nozzle, granule, compactingpressure, mathematical pressing model

For citation

Myuller O.D., Melekhov V.I., Ponomareva N.G., Tyurikova T.V., Khrustaleva M.O. Mathematical Model of the Pressing Process of Thermally-Modified Tree Bark in the Drum-Type Press-Granulators. Lesnoy zhurnal [Forestry journal], 2017, no. 2, pp.130– 148. 10.17238/issn0536-1036.2017.2.130

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