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ПРОЦЕССЫ И АППАРАТЫ ХИМИЧЕСКОЙ ТЕХНОЛОГИИ
UDC 532.527
R. R. Usmanova, G. E. Zaikov
IMPROVING THE TECHNOLOGY OF PURIFICATION OF GAS EMISSIONS PETROCHEMICAL INDUSTRIES
Keywords: flare; dynamic scrubber; synthetic rubber; cleaning of gas emissions; concentration.
The technology of cleaning of gas emissions flares in the production of synthetic rubber. Developed dynamic scrubber for scrubbing gas emissions. Complex studies served as the basis for the design of an air purification system of industrial premises. Purification of gas emissions before combustion in flares has significantly reduced air pollution by toxic substances.
Ключевые слова: факельная установка; динамический газопромыватель; синтетический каучук; очистка газовых выбросов;
концентрация.
Усовершенствована технология очистки газовых выбросов факельных установок в производстве синтетического каучука. Разработан динамический газопромыватель для мокрой очистки газовых выбросов. Комплекс проведенных исследований послужил основанием для проектирования системы очистки воздуха производственных помещений. Очистка газовых выбросов перед сжиганием на факельных установках позволила значительно уменьшить загрязнение воздушного бассейна токсичными веществами.
1. Introduction
On many refineries and petrochemical plants operate flares. They are intended for combustion generated during starting the equipment and in the manufacturing process gases further processing which are economically impractical or impossible, as well as for the incineration of accidental releases.
Burning of gas exhausts on flares allows to reduce pollution of air basin by toxic substances considerably. However salvaging of waste gases of the oil refining and petrochemical enterprises on flares is not a rational method of protection of environment. Therefore it is necessary to provide decrease in exhausts of gases on a torch. Application of effective systems of purification of gas exhausts result in to reduction of number of torches at the petrochemical enterprises.
Measures to clean the air basin in refineries and petrochemical plants should be aimed at improving the culture of production, strict observance of technological regime, improvement of technology to reduce gas formation, reduction of harmful emissions, the development and improvement of methods for the control and treatment of emissions.
2. Engineering design and experimental researches of new apparatuses for gas clearing
Dynamic gas washer, according to fig. 1, 2, contains the vertical cylindrical case with the bunker gathering slime, branch pipes of input and an output gas streams. Inside of the case it is installed conic vortex generator, containing. Dynamic gas washer works as follows [3].
The Gas stream containing mechanical or gaseous impurity, acts on a tangential branch pipe in the ring space formed by the case and rotor.
The liquid acts in the device by means of an axial branch pipe. At dispersion liquids, the zone of contact of
phases increases and, hence, the effective utilization of working volume of the device takes place more.
Fig. 1 - Experimental installation "Dynamic gas
washer"
Installation: 1 - scrubber; 2 - the drive; 3 - the dust loading pocket; 4 - the electric motor; 5 - the batcher; 6 - the fan; 7 - a diaphragm; 8,10 -differenti; 12 - the pressure tank; 13 - rotameter; 14 -sampling instruments
The Invention is directed on increase of efficiency of clearing of gas from mechanical and gaseous impurity due to more effective utilization of action of centrifugal forces and increase in a surface of contact of phases. The Centrifugal forces arising at rotation of a rotor provide crushing a liquid on fine drops that causes intensive contact of gases and caught particles to a liquid.
Owing to action of centrifugal forces, intensive hashing of gas and a liquid and presence of the big interphase surface of contact, there is an effective clearing of gas in a foamy layer.
The aim was to determine the hydraulic resistance of irrigated unit when changing loads on the phases.
Calculations allow for the angular velocity of rotation of the rotor blades and the direction of rotation of the vortex [4]
3. Clearing of gases of a dust in the industry
At the oil flares operate refining enterprise «Synthetic rubber», in Bashkortostan. They are intended for combustion formed at start-up of the equipment and in a process of manufacture of gases, (fig. 3 see).
The dynamic scrubber is developed for decrease in gas exhausts of flares in synthetic rubber production.
Temperature of gases of baking ovens in main flue gas a copper- recovery 500-600 °C, after exhaust-heat boiler 250 °C. An average chemical compound of smoke gases (by volume): 17%C02; 16%N2; 67 % CO. Besides, in gas contains to 70 mg/m3 S02; 30 mg/m3 H2S; 200 mg/m3 F and 20 mg/m3 CI.
Fig. 3 - Static component of pressure the Schema of a flare with scrubber dynamic: 1 - scrubber dynamic; 2 - governor valves; 3 - the ignite burner;4 - a pilotlight burner; 5 - a torch pipe / - waste gas; // - fuel gas; /// - a condensate
The gas dustiness on an exit from the converter reaches to 200/m3 the Dust, as well as at a fume extraction with carbonic oxide after-burning, consists of the same components, but has the different maintenance of oxides of iron. In it than 1 micron, than in the dusty gas formed at after-burning of carbonic oxide contains less corpuscles a size less. It is possible to explain it to that at after-burning CO raises temperatures of gas and there is an additional excess in steam of oxides. Carbonic oxide before a gas heading on clearing burn in the special chamber. The dustiness of the cleared blast-furnace gas should be no more than 4 mg/m3. The following circuit design (fig.4 see) is applied to clearing of the blastfurnace gas of a dust.
Gas from a furnace mouth of a baking oven 1 on gas pipes 3 and 4 is taken away in the gas-cleaning plant. In raiser and down taking duct gas is chilled, and the largest corpuscles of a dust, which in the form of sludge are trapped in the inertia sludge remover, are inferred from it. In a centrifugal scrubber 5 blast-furnace gas is cleared of a coarse dust to final dust content 5-10/m3 the Dust drained from the deduster loading pocket periodically from a feeding system of water or steam for dust moistening. The final cleaning of the blast-furnace gas is carried out in a dynamic spray scrubber where there is an integration of a finely divided dust. Most the coarse dust and drops of liquid are inferred from gas in the inertia mist eliminator. The cleared gas is taken away in a collecting channel of pure gas 9, whence is fed in an aero-sphere. The clarified sludge from a gravitation filter is fed again on irrigation of apparatuses. The closed cycle of supply of an irrigation water to what in the capacity of irrigations the lime milk close on the physical and chemical properties to composition of dusty gas is applied is implemented. As a result of implementation of trial installation clearings of gas emissions the maximum dustiness of the gases which are thrown out in an aerosphere, has decreased with 3950mg/m3 to 840 mg/m3, and total emissions of a dust from sources of limy manufacture were scaled down about 4800 to/a to 1300 to/a.
Fig. 4 - Process flow sheet of clearing of gas emissions: 1 - a Flare; 2 - water block; 3 - raiser; 4 - down taking duct; 5 - Centrifugal scrubber; 6 - scrubber dynamic; 7 - forecastle of gathering of sludge; 8 - hydraulic hitch; 9 - chimney
Such method gives the chance to make gas clearing in much smaller quantity, demands smaller capital and operational expenses, reduces an atmospheric pollution and allows to use water-recycling system [5].
Table 1 - Results of posttest examination
Compoun Concentration Concentration
d at the inlet, g/m3 after clearing, g/m3
Dust 0,02 0,00355
NO2 0,10 0,024
SO2 0,03 0,0005
СО
0,01
0,0019
4. Conclusion
1. The solution of an actual problem on perfection of complex system of clearing of gas emissions and working out of measures on decrease in a dustiness of air medium of the industrial factories for the purpose of betterment of hygienic and sanitary conditions of work and decrease in negative affecting of dust emissions given.
2. Designs on modernization of system of an aspiration of smoke gases of of a flare with use of the new scrubber which novelty is confirmed with the patent for the invention are devised. Efficiency of clearing of gas emissions is raised. Power inputs of spent processes of clearing of gas emissions at the expense of modernization of a flowchart of installation of clearing of gas emissions are lowered.
3. Ecological systems and the result of the implementation of the recommendations is to a high degree of purification of exhaust gases and improve the ecological situation in the area of production. The economic effect of the introduction of up to 3 million rubles / year.
References
1. P.S. Belov, I.A. Golubeva, S.A. Nizova Production ecology chemicals from petroleum hydrocarbons and gas, M: Chemistry, 1991, 256 p.
2. V.V. Tetelmin, V.A. Jazev Environment protection in the oil and gas complex, Dolgoprudnyj: Oil and gas engineering, 2009, 352 p.
3. The patent 2339435 RF.2008
4. V.S.Shvydky, M.G.Ladygichev Clearing of gases. The directory, M: Heat power engineering, 2002, 640 p.
5. V.Straus. Industrial clearing of gases M: Chemistry, 1981, 616 p.
© R. R. Usmanova - Ufa State Technical University of Aviation in Ufa, Bashkortostan, Russia, 12 Karl Marks str., Ufa 450000, Bashkortostan, Russia, [email protected]; G. E. Zaikov- professor, Kazan National Research Technological University in Kazan, Tatarstan, Russia, [email protected].
© Р. Р. Усманова - канд. техн. наук, доц. каф. СМ Уфимского госуд. авиационного технич. ун-та, [email protected]; Г. Е. Заиков - д-р хим. наук, проф. каф. ТПМ КНИТУ, [email protected].
