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Introduction
1. A theme urgency
2. Survey of research and developments
3. The purpose and problems of research
4. Prospective scientific novelty of the received results
5. Conclusions
Bibliography
Coal industry consumes a huge amount of energy resources. Only for heating, sanitary and domestic purposes and heating the air supplied to the mine, the annual cost of about 10 million tons of fuel. It is therefore very important and one of the primary objectives is to save fuel consumed for personal needs of the mine.
Saving just 1% of fuel allows three to four days in a year to work on resource savings. Also at the moment there is an objective and logical trend of increasing average ash content of coal produced, which is due to the constant deterioration of the geological and mining conditions with increasing depth of mining operations, reduction of stocks of low-ash layers discrepancy excavation equipment power developed seams, etc.
Given the above, very urgent problem was the introduction into service furnaces designed to burn low-grade high-ash coals and waste coal. Progressive method of burning low-grade and of high (80%) fuels, the burning of low-temperature fluidized (boiling) layer. This method of burning fuel has a high level of mixing fuel and an oxidant, increased compared with the grate furnaces the residence time of fuel in the combustion zone, the intense heat transfer to the heating surface, the lack of moving parts in the combustion volume, the possibility of combustion in a single unit of fuels of different composition and quality, reduced 1-5% fuel content in the layer. This method facilitates the combustion of fuel ignition, prevents sintering of the fuel particles and slagging of convective heating surfaces.
The very important problem of energy-saving, and one of the options for its solution is to use non-conventional technologies, such as the burning of high-solid fuel in low temperature fluidized bed. In particular, the furnace can be used as a source of coolant for the autonomous gas-air heater designed for heating the barrel during the winter.
However, one of the constraints the implementation of such systems is the imperfection of automated data management technology object, which represents a number of separate control loops, executed on the basis of outdated controls of the type P-25. One of the conditions necessary for the synthesis of a qualitatively new automation system is to establish mathematical relationships furnace fluidized bed.
To date, there is a considerable number of works on the subject. Review and analysis of studies performed before 1989 [1], as well as a later-these works [2,3,4] have identified the following shortcomings of existing mathematical models:
- Assumed to be known the value of the mass flow of fuel, while at the present time, technically achievable only volumetric dosing;
- Fuel parameters: ash, moisture, distribution of fuel particles on the size of frames involve known in advance and to obtain dynamic characteristics of the system, we must make every time a new cycle of computer operations;
- Do not take into account the presence of thermal destruction and mechanical abrasion of particles of fuel in a fluidized bed;
- Difficulty adjusting parameters of the model when new experimental data or use it for various grades of fuel limits the scope of application of the dependencies.
Thus, the purpose of work is the synthesis of building on existing relationships of analytical mathematical model of the combustion chamber low temperature fluidized bed with the following tasks:
- Taking into account the technological equipment and environmental conditions;
- The ability to change the basic characteristics of the fuel directly in the process of modeling as a hand, and on a predetermined algorithm.
Prospective scientific novelty consists in the following:
- development of a mathematical model of fluidized bed;
- develop a mathematical model of low-temperature fluidized bed combustion chamber;
- simulation of the automatic ignition fluidized bed;
- obtaining transfer characteristics of fluidized bed combustion chamber with variable parameters, fuels and modes of operation;
- synthesis of automatic control system of furnace processes.
We investigated the process of burning solid fuel in the boiler blast a low temperature fluidized bed. This method of burning fuel is becoming more widespread. Since its introduction solved very urgent and important task on the use of low-grade and high-ash coals.
The paper made a critical review of technical solutions in the automation process.
Based on the heat balance equation fluidized bed shows the transfer function along the contour "toplivo". Set of mathematical relationships furnace fluidized bed. Is obtained in the developed mathematical model for the temperature of the layer to a step change in performance забрасывателя.Разработанная mathematical model allows us to obtain the transient characteristics of fluidized bed combustion chamber with variable parameters, fuels and modes of operation, and to further carry out the synthesis of automatic control system of furnace processes.
1. Махорин К.Е., Хинкис П.А. Сжигание топлива в псевдоожиженном слое. –К.: Наукова думка, 1989. – 204 с.
2. Корчевой Ю.П., Пацков В.П., Редькин В.Б., Майстренко А.Ю. Расчет выгорания частиц твердого топлива в кипящем слое с учетом внутрипористого реагирования// Тепломассообмен ММФ-92. Тепломассообмен в дисперсных системах: Т.5.-Минск. АНК"ИТМО им. А.В. Пылова", АНБ.-1992.-С. 168-170.
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5. Бородуля В.А., Гупало Ю.П. Математические модели химических реаторов с кипящим слоем. - Мн.: Наука и техника, 1976, 208 с.
6. Забродский С. С. Гидродинамика и теплообмен в псевдоожиженном (кипящем) слое. М.—Л., Госэнергоиздат, 1963. 488 с.
7. Бородуля В.А., Пальченок Г.И., Васильев Г.Г., Дрябин В.А., Галерштейн Д.М. Тепломассообмен и кинетика горения твердого топлива в кипящем слое // Проблемы тепло- и массообмена в современной технологии сжигания и газификации твердого топлива. Мате-риалы международной школы-семинара. Минск, 1988, ч. 2. – с. 3-23.
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10. Беляев А.А., Рогайлин М.И. Низкотемпературные методы сжигания угля в кипящем слое. М.: ЦНИЭИуголь.-1986.
11. Бочаров А.А., Вискин Ж.В. Методика реконструкции и эксплуатации топок для сжигания высокозольных углей в кипящем слое. - Донецк.:Радянська Донеччина, 1989. - 123с.
12. Баскаков А.П., Лукалевский Б.Б., Лукленов И.П. Расчеты аппаратов кипящего слоя. - М.:Химия. - 1986.
13. Хинкис П.А., Махорин К.Е., Бочаров А.А. Эффективность сжигания твердого топлива в кипящем слое //Химическая технология №1. - 1987. - с. 37-41.
When writing this abstract the master’s qualification work is not completed. Date of final completion of work: December, 1, 2011. Full text of the work and materials on a work theme can be received from the autor or his scientific supervisor after that date.
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