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Abstract

Contents

1. ANALYSIS OF EMISSIONS THERMAL POWER PLANT COKE ENTERPRISES. MARKET WATCH MEANS AND METHODS FOR MEASURING THE CONCENTRATION OF DUST

1.1. Analysis of the dust-gas environment of thermal power plant and the rationale for the control of dust and destabilizing factors

The main factors leading to the formation of aerosols polluting the atmosphere – is burning processes carried out at the thermal power plants, at waste incineration plants in residential furnaces, cement kilns, as well as in the production of ferrous and non-ferrous metals from natural ores. The particles produced by combustion may contain dangerous substances such as asbestos, heavy metals and arsenic. Metal oxides are the main component of the inorganic particles in the atmosphere. Also, in a variety of industries such as the manufacture of porcelain, ceramic, cement, chemicals, medicines, foods, like raw materials and semi-finished products used powder, granular and bulk materials, which also contribute to the pollution of the environment in the event of violations of technological processes cleaning exhaust gases.

The main parameter characterizing the state aero dispersed systems in various industries the concentration of particles in the process gases suction and filtration systems, as well as the exhaust gases that pollute the atmosphere.

These systems are unstable in time and space. The electrification of the particles, their sedimentation, changing the dispersed composition, adhesion and other phenomena contribute to the process of measuring the mass concentration of the continuous monitoring instrumentation additional errors. Therefore, the correct choice of the instruments is a very important task.

The particle size of the emitting sources of various industries can be from 0.1 to 120 microns in diameter at a concentration of 0.3 mg/m3 to 150 mg/m3. Fine particles pollute the air we breathe, and the large particles at high concentration of negative impact on the environment, which also violates the human condition.

The main tools are collecting dust bag and electrostatic filters. Considering that in many cases this dust is the end product has a high price, for example, cement production, the reduction efficiency of the filters results than pollution and significant financial loss [1].

The composition of emissions is characterized by the following data: sulfur dioxide: 0.09 mg/m3, hydrogen sulfide: 0.006 mg/m3, phenol: 0.007 mg/m3, carbon monoxide: 1.23 mg/m3, nitrogen dioxide: 0.068 mg/m3, ammonia: 0.19 mg/m3, different kinds of dust: 20 mg/m3 disulfide, iron oxide, manganese and its compounds, lead compounds, nitrous oxide, hydrogen cyanide, sulfuric acid, carbon black, spray welding, saturated hydrocarbons, aromatic hydrocarbons iron oxide.

Coke plants by harmful, especially for the most dangerous for people carcinogenic emissions occupy one of the leading companies in other industries.

Coke production is a set of specific industries related to the high temperature treatment of coal charge without access to air and process gas oven, released at the same time in order to get a number of valuable chemical products.

Conventional processes, in some cases associated with the release into the atmosphere of harmful substances included in the coke oven gas, such as ammonia, carbon monoxide, nitrogen oxide, sulfur dioxide, hydrogen sulfide, hydrogen cyanide, benzene, naphthalene, phenol, carbon and coke dust. The main sources of emissions are well known, they are: the load and the issuance of furnaces, excess gases of facility of dry quenching coke, suction gas of preparations of coal and sort of coke systems, pipes coke oven batteries, as well as diffuse releases doors, racks, cargo hatches, etc [6].

Part of the coke oven gas is supplied to plant’s thermal power plant which is burned to produce electricity, which is provided by the entire plant, and steam used in the process.

Dust Collection from pipe of thermal power plant can be made by cyclone dust collector.

The dust-laden gas tangentially enters the inlet scrubber. In case there is a division of flows on clean and dust-covered. The dust particles move closer to the housing wall due to the fact that they have higher kinetic energy as the mass of the dust is more than the air mass.

1.2. Analytical review of the methods of measuring the concentration of dust in the atmosphere of dust emissions thermal power plant

Methods of measuring the concentration of dust are divided into two classes: those based on the preliminary deposition of dust and methods that do not require the deposition. Measurement of the concentration of dust with its deposition, in most cases inconvenient, because there is no possibility of dust-gas condition monitoring in real time. This requirement is satisfied by only one of the methods based on preliminary deposition of dust. This method of measuring differential pressure in the filter. The methods without sampling include optical methods (absorption, scattering integral method), electrical methods (induction, contact-electric, capacitive, piezoelectric), acoustic. Most easy to implement and accurate are optical methods. Also, they do not affect the dust and gas environment in which the measurements. Among optical methods in research polydisperse integral dust scattering method has an accuracy of 15% and the absorption – 30%. Except for the low error, the method has sensitivity even at low concentrations and the absence of the zero change.

State diagram of Moore FSM

Figure 1 – Light scattering particle
(animation: 6 frames, 6 cycles of repeating, 61 kilobytes)
(For p << 1 (Rayleigh scattering) p >> 1 (Mie scattering))

This master's work is not completed yet. Final completion: December 2013. The full text of the work and materials on the topic can be obtained from the author or his head after this date.

References

  1. Клименко А.П. Методы и приборы для измерения концентрации пыли / А.П. Клименко. – М.: Химия, 1978. – 198 с.
  2. Справочник химика: в 6 т. Т. 4: Аналитический анализ, спектральный анализ, показатели преломления /Под. общ. ред. Б.П. Никольского. – Л.: Химия Ленингр. отделение, 1967. – 920 с.
  3. Галенко Ю.А. Моделирование коэффициента теплового излучения полубесконечной дисперсной среды / Ю.А. Галенко, М.О. Сысоева. // Ползуновский вестник. Алтайский государственный технический университет им. И.И. Ползунова. – № 1 – 2. – 2008. – с. 28-32.
  4. Шифрин К.С. Рассеяние света в мутной среде. / К.С. Шифрин. – М. – Л.: Госттехиздат, 1951. – 288 с.
  5. Штокман Е.А. Очистка воздуха. Учебное пособие. / Е.А. Штокман. – М.: Изд-во АСВ, 2007. – 312 с.
  6. Исследование технологических методов сокращения выбросов газообразных токсичных веществ в процессах коксохимического производства. [Электронный ресурс]. Режим доступа: http ://masters.donntu.ru/2009/fizmet/vislobod/diss/index.htm – дата обращения: 12.05.2012 – название с экрана
  7. Корольченко А. Пожаровзрывоопасность промышленной пыли / А. Корольченко, М.: Химия, 1986. – 235 с.
  8. Бараночников М.Л. Приёмники инфракрасного излучения / М.Л. Бараночников, М.: 1985. – 94 с.
  9. Коузов П.А. Основы анализа дисперсного состава промышленных пылей и измельчённых материалов / П.А. Коузов, Л.: Химия, 1987. – 264 с.
  10. ван де Хюлст Г. Рассеяние света малыми частицами / Г. ван де Хюлст, М.: Издательство иностранной литературы, 1961. – 536 с.