The structure of wood raw materials at factories of particle boards of different capacities

The composition of wood raw materials was investigated at four chipboard plants with a capacity of 100, 120, 200 and 480 thousand m3 of boards per year. Currently, the main raw material for board factories is solid stem wood in the form of firewood and pulpwood. Its share is 63...100% of all raw materials, the average value for four plants is 70.2%. The rest of the raw material is waste from various wood-processing industries. The proportion of used waste increases with an increase in the capacity of the board plant from 0 to 32.0%. On average, the consumption of waste is as follows: imported chips 4.7%, slab 10.9%, sawdust 7.1%, waste from veneer and plywood production 4.3%, waste from board production 1.2%, recyclable materials 1.6%. Plants with a capacity of up to 120 thousand m3/year use waste that does not require the creation of additional technological sections for the preparation and processing of raw materials: slab and imported chips. They are processed in the basic technologies for making wood particles. Plants with a capacity of 200 and more thousand m3/year use not only slab and imported chips, but also other types of wood waste: sawdust, waste from the production of veneer, plywood, boards, and recyclable materials. They require special technologies for their preparation in new areas, which include technological and transport equipment. When planning the use of woodworking waste, it is necessary to take into account the peculiarities of each type of waste, which limit the upper level of their share in the composition of raw materials. In pine slab, the bark content is 38.2%, which is 3.9 times higher than in stem wood. A significant increase in the proportion of bark in the slab leads to a decrease in the strength characteristics of the slab. In addition, the bark of the slab may contain mineral impurities and pieces of metal. They get there during the harvesting, transportation and storage of the sawlogs. The average length of sawdust particles does not exceed 5 mm. Only microchips for the outer layers of the slab can be made from such raw materials. The composition of coniferous and deciduous raw materials is approximately the same: the share of conifers is 46.8%, deciduous 53.2%. The bulk of deciduous raw materials are firewood and pulpwood (47.8 out of 53.2%). Coniferous raw materials mainly come in the form of wood processing waste (wood chips, slabs, sawdust). The use of pine and spruce is roughly equal. Aspen predominates among deciduous species – 38.2% versus 15.0% for birch. This is due to the fact that the bulk of the firewood supplied to the enterprise is aspen trunks. Comparison of the consumed raw materials at present and in 1984 shows that the share of the main raw materials, firewood and pulpwood, is maintained practically at the same level of 70.2 and 68.1%. Consumption of imported wood chips decreased by 3.6 times from 16.9 to 4.7%. The use of waste wood processing industries (slab, sawdust, waste veneer and plywood), on the contrary, increased 1.7 times from 13.1 to 22.3%. As a result, the share of coniferous wood in the composition of modern raw materials has almost doubled from 23...25% to 46.8%, and the share of deciduous species has decreased from 75...77% to 53.2%.

1. Vasil'ev V.V. Aktual'nye tekhnologicheskie problemy proizvodstva sinte-ticheskih smol i drevesnyh plit. Izvestiya Sankt-Peterburgskoj lesotekhnicheskoj akademii, 2020, iss. 230, pp. 173–186. DOI: 10.21266/2079-4304.2020.230.173-186. (In Russ.)

2. Merkulova A.F., Vasil'ev V.V. Opredelenie soderzhaniya mineral'nyh primesej i metalla v drevesnyh chasticah dlya proizvodstva drevesnostruzhech-nyh plit. Drevesnye plity: teo¬riya i praktika: 20-ya Mezhdunar. nauch.-prakt. konf., 15–16 marta 2017 g. SPb.: Izd-vo Poli¬tekhn. un-ta, 2017, pp. 76–80. (In Russ.)

3. Otlev I.A., SHtejnberg C.B., Otleva L.S., Bova YU.A., ZHukov N.I., Konash G.I. Spravochnik po proizvodstvu drevesnostruzhechnyh plit. 2-e izd. pe-rerab. i dop. M.: Lesn. prom-st', 1990. 384 p. ISBN–5–7120–0242–6. (In Russ.)

4. Poluboyarinov O.I. Plotnost' drevesiny. M.: Lesn. prom-st', 1976. 160 p. (In Russ.)

5. SHalashov A.P. Sostoyanie i perspektivy razvitiya proizvodstva drevesnyh plit v Rossii. Drevesnye plity i fanera: teoriya i praktika: 24-ya Vserossij-skaya nauch.-praktich. konferenciya. 17–18 marta 2021 g. SPb.: Politekh-Press, 2021, pp. 10–13. (In Russ.)

6. SHalashov A.P. Sostoyanie i perspektivy razvitiya rynka drevesnyh plit v Rossii. Sostoyanie i perspektivy razvitiya proizvodstva drevesnyh plit: sb. dokl. 23-ya Mezhdunar. nauch.-prakt. konf., 18–19 marta 2020 g. Balabanovo: ZAO «VNIIDREV», 2020, pp. 3–15. (In Russ.)

7. SHalashov A.P., Strelkov V.P., SHCHeglov P.P., Dejneko D.V., ZHaravin V.D. Sovremennoe sostoyanie i predlozheniya po razvitiyu proizvodstva drevesnyh plit v Rossii. Drevesnye plity: teoriya i praktika: Shestaya nauch.-prak¬tich. konferenciya. 19–20 marta 2003 g. SPb.: SPbGLTA, 2003, pp. 4–7.

8. Shvartsman G.M., Schedro D.A. Proizvodstvo drevesnostruzhechnyih plit. 4-e izd., pererab. i dop. M.: Lesn. prom-st, 1987. 320 p. (In Russ.)

9. Ugolev B.N. Drevesinovedenie i lesnoe tovarovedenie. M.: GOU VPO MGUL, 2007. 351 p. (In Russ.)