Biomass is one of the most plentiful and well-utilized sources of renewable energy in the world. Broadly speaking, it is organic material produced by the photosynthesis of light. The chemical material (organic compounds of carbons) are stored and can then be used to generate energy. The most common biomass used for energy is wood from trees. Wood has been used by humans for producing energy for heating and cooking for a very long time.
Keywords: energy, biomass, fractionation biomass, alternative energy, mechanical vibration.
Biomass has been converted by partial-pyrolysis to charcoal for thousands of years. Charcoal, in turn has been used for forging metals and for light industry for millennia. Both wood and charcoal formed part of the backbone of the early Industrial Revolution (much northern England, Scotland and Ireland were deforested to produce charcoal) prior to the discovery of coal for energy.
Wood is still used extensively for energy in both household situations, and in industry, particularly in the timber, paper and pulp and other forestry-related industries. Woody biomass accounts for over 10 % of the primary energy consumed in Austria, and it accounts for much more of the primary energy consumed in most of the developing world, primarily for cooking and space heating.
It is used to raise steam, which, in turn, is used as a by-product to generate electricity. Considerable research and development work is currently underway to develop smaller gasifiers that would produce electricity on a small-scale. For the moment, however, biomass is used for off-grid electricity generation, but almost exclusively on a large-, industrial-scale. For receiving of the energy at first is processing fractionation of biomass
The term «vibration» is mechanical vibrations with small amplitude and very low frequency. Mechanical vibrations can be used as a useful phenomenon for fractionation of biomass. Screening (plan sifter, sieving) is the process of separation of bulk, lump and granular material on products of various sizes (classes) with the screening surfaces sieve, lattice [1]. For the separation of biomass into fractions used preparatory screening. Preparatory screening of biomass used for further unloading of biomass in the reactor of a biogas plant to two classes of particle size. Preparatory screening — screening for separating material into several size fractions, intended for subsequent separate treatment. In this case, for further processing of biomass in the reactor. Vibratory «Shaker» refers to the character of movement of the working body to the movable flat screens, by location of the screening surface — to the sloping, with rectilinear oscillations. Screens with rectilinear oscillations directed at some angle to the plane of the screening surface, operate in sloping or horizontal position. The material in this case is moved on the screening surface because of the impact on him by the working body (vibration displacement). Inertia screens represent oscillatory system, which for the one oscillation period occurs one complete cycle of conversion of kinetic energy into potential energy and vice versa. As a result, theoretically is not required energy consumption to overcome the forces of inertia of the moving masses and elastic forces of shock absorbers (springs). Energy is needed only to overcome the dissipative forces (friction, loss of particles when striking of sieves, etc.). Practically found that 1 kg of particulate material which is at the vibrating surface necessary 0.002–0.003 kW drive motor. Experimental studies show that for transporting wet and sticky cargoes with intensive tossing, speed of movement approach to the speed of the bulk material, and in some cases even superior to its. When moving with a toss occurs uniform distribution of material across the width of the working body, as a result of the periodic loss of contacts, decreases effect of frictional forces and particle size reduction. Vibration modes in which sediment moves tossing considered more technologically advanced. [2] Due to the humidity of biomass less than 92 %, the properties approach to the properties of bulk material. The main technological parameters of the process of screening material are: productivity screen and screening efficiency. The values of these parameters are determined and conditioned by a number of factors, which can be divided into two main groups: 1) factors depending on the physical and mechanical properties of the material; 2) structural and mechanical factors (size of screen and its regime). For research process of fractionation of biomass. are selected following parameters: — structural and operational parameters: 1. the engine speed; 2. the size of the cells; 3. the speed of movement biomass; 4. mass; 5. angle of the slope to the horizon; 6. the frequency of the vibrator; 7. the spring stiffness of vibration machine; 8. vibratory drive power; 9. the friction force; 10. the temperature of the mass of biomass; By structural and mechanical factors are included: sieve design, the ratio of its length to width, the method of supplying the material to the screening surface and the screen mode of the mechanical parameters. Form of the openings of the screening surface has a significant effect on screening. The ratio between the width B of the screen and its length L for inclined screens inertial is B:L ൎ1:2. The dependence of the efficiency of extraction of small grains from the length of the path traveled by the material from the place of loading, has exponential nature. Most of the small classes (approximately 60–70 %) are sifted out at the first third of the length of the screen. Screening power. The main requirement for a method for supplying material to the screening surface is its uniformity. Necessary to supply the material uniformly in time to distribute it evenly over the entire width of screen that provides a constant average speed of material over the screen thickness and stability, and consequently effectiveness of screening consistency and quality screening. The angle of inclination of the box has a significant impact on the effectiveness of screening. In practice, this angle is taken between 15 and 26 degrees for inertial inclined screens. The most advantageous angle, which provides the highest efficiency at a given performance or efficiency, established by experimentation. The frequency and amplitude of the oscillations are selected in accordance with passport data of the manufacturer. Conclusion: vibration machine refers to the inertial inclined screen with rectilinear oscillations. On the process of fractionation affect structurally-mechanical parameters — width and length of the screen, the power screen, the angle of inclination to the horizon, the frequency and amplitude of the oscillations, as well as the size of the cells of the screening surface.
References:
- Akinshin IK, Baschenko NT, OS Bogdanov, Zverevich, Kostin IM, Olevskii VA, VA Perov Directory of enrichment of ores. Volume 1 of the preparatory process. — Volume 1, Issue 2, Vol. — Moscow: Nedra, 1982.
- Dudka AA, Justification of the process and the parameters of the vibration filter to separate the manure into factions: Author. dis. cand. tehn. Sciences: 05.20.01. — Kharkov, 1983.
