Съдържание


INNO 1/2017 2017

CBC KRAFT COOKING OF HARDWOODS WITH VARIOUS QUALITY OF CHIPS

Автори: Anton Geffert, Jarmila Geffertova, Blazej Seman

Резюме

The aim of this work was to highlight the importance of chip thickness and type of wood for pulp production under the conditions of modern displacement sulphate cooking CBC (Continuous Batch Cooking).

The main condition for optimal delignification process is the speed how the cooking chemicals come into contact with particular wooden fibres. This speed is given by chips quality – their dimensional, chemical and moisture uniformity.

The optimal thickness of well-impregnable sapwood chips 3–4 mm and recommended thickness for chips prepared from hard impregnable heartwood 2–3 mm are very important for impregnation phase of CBC cooking.

Different progress of impregnation of chips with thickness of 2–3 and 4–5 mm can be explained by different impregnation surface - the surface of fine chips was larger by 34.6%.

There are no significant differences between a conventional cooking of chips with different size of the monitored wood species. Influence of the chip thickness and the type of wood on monitored parameters (yield, kappa number, amount of undercooks and REA) in CBC cooking was more evident, because of very high dry matter value of used chips.

Regular impregnation and delignification of chips from hardwood mixture necessitate preparing of chips with thickness app. 3 mm from species with heartwood share greater than 50% (oak, black locust). The recommended ratio of sapwood and heartwood mixture is 4:1 (under realistic practice).

The suitable combination of above stated parameters allows the production of high quality pulp from non-uniform chips.

Ключови думи: wood chips quality, displacement cooking, uniformity of chips, impregnation, delignification, yield

EN Version

HARDNESS OF WOOD IN SOME OAK SPECIES

Автори: Diyana Mladenova, Nikolai Bardarov

Резюме

The oaks are one of the most important species for our Dendroflora. This study of hardness complements the knowledge of the properties of their wood. Wood is a non-homogeneous material and its properties differ in different parts of the stem. Hardness is a property that is directly related to the construction of the wood. That is why knowledge of this property will be an important step towards more rational use of oak wood.

The work presents data on the hardness of the wood of pedunculate oak (summer) and sessile oak (winter oak). The influence of the habitat and the radius of the stem is examined. In order to compare the individual samples, the qualitative hardness coefficient was determined.

Ключови думи: wood, oak, hardness, sessile oak, pedunculate oak

EN Version

QUALITY GRADING OF WOODEN POLES PRODUCED BY SCOTS PINE (PINUS SYLVESTRIS L.) FORESTS IN WEST RODOPI (N. GREECE)

Автори: Dimitrios Koutsianitis, Elias Voulgaridis

Резюме

Trunks of Scots pine (Pinus sylvestris L.) are widely used for poles in power transmission and telecommunication lines. The objective of this work was to apply visual quality indexes on wooden poles, based on basic wood defects. Poles were characterized according to various defects and geometric characteristics, namely: knots, spiral grain, sweep, taper, rate of growth and dimensions. Poles that did not meet the established minimum requirements of the standards applied by the public power corporation, were rejected. The results showed that from the 82 trees investigated a high percentage (90.2%) met the standards and were suitable as power transmission poles.

Ключови думи: Scots pine, poles, defects, visual grading

EN Version

TRANSFORMATION OF TWO MUTUALLY CONNECTED MODELS FOR CONVECTIVE HEATING OF WOOD DETAILS BEFORE THEIR LACQUERING IN A FORM, SUITABLE FOR PROGRAMMING

Автори: Nencho Deliiski, Neno Trichkov, Zhivko Gochev, Dimitar Angelski

Резюме

Using the explicit form of the finite-difference method, two suggested by the authors mutually connected mathematical models have been transformed in a form, suitable for programming. For the numerical solution of the transformed models, a software program has been prepared in the calculation environment of Visual Fortran Professional. With the help of the program, the 1D distribution of the temperature along the thicknesses of flat oak details and of their carrying transport rubber band with hw = 16 mm, lw = 0.6 m, u = 0.08 kg.kg-1, hB = 4 mm,
bB = 0.8 m, and t0 = 20 oC, during unilateral convective heating for a period of 10 min at tha = 100 oC, vha = 2 m·s-1, 5 m·s-1, 8 m·s-1, and tnha = 20 ºC in order to ensure suitable thermal conditions for the subsequent details’ lacquering has been calculated, visualized and analyzed.

Ключови думи: oak details, unilateral convective heating, lacquering, carrying rubber band

EN Version

INFLUENCE OF THE TEMPERATURE COMBUSTION OF FUEL-WOOD TO CONTENT ASH

Автори: Ladislav Dzurenda, Adrián Banski

Резюме

In this contribution, there are presented the results of experiments determining the influence of combustion temperature of fuel-wood on the production of ash. They confirm current knowledge about the low production of ash from wood, and specify the functional dependences between the influence of temperature at intervals of t = 500°C – 1000 °C on the production of ash from the wood of tree species: Norway spruce, White birch, European beech, English oak and Black locust.

The functional dependences of ash production on the combustion temperatures are instrumental for objectification of information about ash production from energy facilitiesfor energy, environmental, and ecological analyses and balances.

The proportion of ash from fuel-wood can be done according to standard ISO 1171:2003, or standard EN14775:2010. These standards differ in the temperature of combustion of the fuel wood sample. ISO 1171:2003 burns fuel at t = 815 °C while EN14775:2010 at t = 550 °C. Disregarding the aforementioned facts about the dependence of production of ash on the combustion temperature causes errors. By interchanging the norms ISO1171:2003 with EN14775:2010, the balances from combustion of spruce wood generate a relative error of 44.58%. The balances from combustion of wood of black locust generate a relative error of 19.10%.

Ключови думи: fuel, wood, combustion, temperature, ash

EN Version

OPPORTUNITIES FOR SUSTAINABLE FOREST MANAGEMENT IN YUNDOLA

Автори: Ivan Paligorov, Emil Galev, Stanislava Kovacheva, Elena Dragozova, Ivaylo Ivanov

Резюме

The forest management in Yundola has been studied under the project INTEGRAL - Future-Oriented Integrated Management of European Forest Landscapes by the funding Scheme: FP7 Seventh Framework Programme. This is one of the project case study areas in Europe. This is one of the objects of a test project in Europe. The results of the survey are the bases of the development of future scenarios for forest management and they make it possible to create the integrated management strategies for sustainable use of forest landscapes. The supply of all forest ecosystem goods and services is expected to increase in all case studies in the future. This causes an emerging need for a pro-active management approaches to handle trade-offs and strike a balance in order to address sustainability concerns in building the bio-based economy.

Ключови думи: forest landscapes, sustainable management, INTEGRAL, forest ecosystem goods and services

EN Version

RATTAN: THE TEMPTATION OF CONTEMPORARY DESIGN

Автори: Regina Raycheva

Резюме

Rattan is an exclusively lightweight material with exotic character; it is a symbol of Asiatic countries; of gardens and resort hotels. 20th C designers are tempted by this material that combines well with metals and wood. Rattan itself is imitated with artificial materials, used to knit garden furniture; it is a preferable choice because it is indestructible by atmospheric conditions. Today, great designers are inspired by the formal potential of rattan both as a structural material and as a mesh or woven panels used for the wide surfaces of seating and lying furniture (seats and backrests). They are not limited only in the garden field of application; they use the potential of this material for the dwelling. In this paper, we are going to consider designer works of different periods of the 20th and 21st century, that are influenced by the qualities and specifics of the material rattan; by analyzing and classifying those features that make it so attractive to furniture designers.

Ключови думи: Rattan, Design, Form-building, Structure

EN Version

STUDY ON THE DENSITY OF OAK WOOD

Автори: Diyana Mladenova, Evgeni Tsavkov, Nikolai Bardarov

Резюме

The density is assumed to be a complex parameter of quality wood. On the one hand, it depends on the anatomical structure of the wood, the other largely determine all other mechanical properties and influence the processing and use of wood.

Work considered the density of oak wood, sourced from different habitats in the country and its distribution in the radius of the stem. The influence of age, the width of the annual ring, habitat and altitude.

Ключови думи: wood, oak, density, annual ring

EN Version

APPLYING THE SOFTWARE PACKAGE TABLE CURVE 2D FOR COMPUTATION OF PROCESSING AIR MEDIUM TEMPERATURE DURING FREEZING IN A FREEZER AND DEFROSRING OF LOGS

Автори: Natalia Tumbarkova, Nencho Deliiski

Резюме

A mathematical description of the change in the processing air medium temperature Tm during freezing in a freezer and subsequent defrosting of logs using a software package Table Curve 2D v.5.01 has been suggested. This package allows for the selection of equations, which provides the best similarity between the calculated with them values of Tm during the log’s freezing and defrosting processes and the respective experimentally established data for Tm. The values of the coefficients in the selected equations have been determined in the work for the cases of decreasing in Tm in the range from about 20 оС to about –30 оС during separately 30 h freezing and of the following increasing in Tm up to about 20 oC during the subsequent 30 h or 50 h defrosting of 6 pine logs with diameter of 240 mm and length of 480 mm.

Ключови думи: temperature, processing air medium, freezing, defrosting, pine logs, Table Curve

EN Version