HYDRODYNAMICS OF A GALVANIZED PLATE SCRUBBER

ABSTRACT

In the article, the influence of various parameters of the surface contact element of the plate scrubber for dust gas cleaning in the wet method on the cleaning efficiency of the device is studied. Variable factors in experimental studies are the diameter of the liquid nozzle d_sh=3 mm, liquid consumption Q_liq=0.071÷0.189 m³/h, the diameter of the hole of the spherical plate dtar=2, 3 and 4 mm, the angle of installation of the spherical plate to the device α = 15^o; The number of 30^o and 45^o spherical plates is 2 according to the installation angle and the height of the experimental device, gas velocity υ_g=7.4÷28.8 m/s. The gas density for a mixture of air and dolomite dust is determined as ρ_g=3.38 kg/m³ and 2160.3 mg/m³. It was determined in the experiments that the hydraulic resistance of the scrubber with a spherical plate is 1.7 times lower than that of the existing structure.

АННОТАЦИЯ

В статье исследовано влияние различных параметров поверхностного контактного элемента пластинчатого скруббера для очистки пылегазовых газов мокрым способом на эффективность очистки устройства. Варьируемыми факторами при экспериментальных исследованиях являются диаметр жидкостного сопла d_sh=3 mm, расход жидкости Q_liq=0.071÷0.189 m³/h, диаметр отверстия сферической пластины dtar=2, 3 и 4 mm, угол установки сферической пластины к устройству α = 15o; Количество сферических пластин 30° и 45° - 2 в зависимости от угла установки и высоты экспериментальной установки, скорость газа υ_g=7.4÷28.8 m/s. Плотность газа для смеси воздуха и доломитовой пыли определяется как ρ_g=3.38 kg/m³ и 2160,3 мг/м³. В опытах установлено, что гидравлическое сопротивление скруббера со сферической пластиной в 1,7 раза ниже, чем у существующая структура.

Keywords: scrubber, hydraulic resistance, resistance coefficient, liquid consumption, gas velocity, swash plate, energy consumption, cleaning efficiency.

Ключевые слова: скруббер, гидравлическое сопротивление, коэффициент сопротивления, расход жидкости, скорость газа, перекосная пластина, энергопотребление, эффективность очистки.

Introduction

It is urgent to increase the contact surfaces in wet gas cleaning devices and thereby justify the optimal parameters of hydraulic resistance, cleaning efficiency and energy consumption. Therefore, most of the scientific and research works carried out in this field are aimed at increasing the surface contact elements in the device, creating a simple construction of the element, and studying the processes of hydrodynamic and effective cleaning of dust gases.

It is known from the results of previous scientific research that the simplification of the design of the surface contact element reduces the hydraulic resistance in the device, but has a negative effect on the cleaning efficiency of the device. In addition, it increases the outflow of liquid droplets along with the purified gas from the device. This, in turn, increases the accumulation of dust particles in the pipes of the device. besides, it is necessary to take into account the physical and chemical characteristics of dusty gases to be cleaned when choosing a construction suitable for the process.

Research object and subject

In this research work, effective cleaning of dusty air and toxic gases coming out of AS-72M workshops of "Fergonazot" JSC, the problem of ensuring energy efficiency and increasing productivity and quality of work is set, and its positive solution is to improve the environmental condition of the enterprise's territory, to create the possibility of reusing captured dust and toxic gases in production processes. Therefore, the main goal of the work was to create modern designs of dust capture devices and apply them to production processes [1,2].

Based on the above, some constructions and their working parameters of the currently used and promising constructions in scientific research work were systematically analyzed. [3, 4, etc.]. The results of the systematic analysis were processed in the MATLAB program and the advantages and disadvantages of the devices were determined. The results of the analytical analysis revealed that scrubbers are the most effective devices that can be used in chemical industry dust cleaning. However, some shortcomings of this type of device, for example, high energy consumption and hydraulic resistance, and short contact time between dusty gas and working fluid, indicate the need to carry out scientific research work on the improvement of devices of this construction.

Based on the results of the systematic analysis, an improved structural scheme of the scrubber was developed and a spherical plate was installed on the device at a certain angle of inclination [5]. Figure 1 shows a drawing of the plate scrubber and Figure 2 shows the installation of the spherical plate in the device.

Figure 1. Structural diagram of a plate scrubber
1–stand; 2–support; 3–cone; 4,7,10,12–socket (A,B,V,G) ; 5-glass; 6- obechaika; 7-dnisha; 9-drop reflector; 11-diffuser; 13–nozzle; 14-plates; 15,18 studs; 16-drop holder; 17-mechanical sprinklers

The scrubber is composed of a cone and a secondary gas transmission pipe and a fan, a liquid spraying nozzle and a pump, liquid-gas contact increasing plates, a drop holder, a cylindrical vertical body and a pipe for releasing the purified gas to the atmosphere. . A gas distributor is installed on the guide pipe, which distributes the secondary gas along the cross-section of the cylindrical vertical body. Four nozzles (fluid nozzles) are installed on the upper part of the liquid spraying device (nozzle) at an interval of 90⁰ degrees, and it is connected to the guide pipe with a seal and a sealing ring. The nozzle holes are arranged parallel to the liquid.

The main advantage of the device compared to existing scrubbers is that, firstly, its nozzles contact the gas to be cleaned by spraying the liquid in a full state, and secondly, the installation of the plates in an inclined position ensures the curvilinear movement of the gas flow in the liquid environment. This, in turn, increases the mass transfer coefficient [18].

Figure 2. General view of the spherical plate

However, the laws of change of device hydraulic resistance, cleaning efficiency and energy consumption have not been studied in different parameters of the rotary plate scrubber. Therefore, this research work is aimed at the application of a new spherical plate to the scrubber and the justification of its optimal parameters.

To carry out the research, a laboratory model of the device was developed and the parameters of the selected auxiliary devices (fan and water pump) were determined experimentally. Figure 3 shows an overview of the laboratory model.

Figure 3. Overview of the laboratory model

Research results

In order to form a film by spraying liquid evenly on the surface of the spherical plate in the device, an S32-412 nozzle (hole diameter d_sh = 3 mm, 4 pieces were installed according to the diameter of the device. The installation interval was selected according to the liquid spraying angle a. Centrifugal pump 9 (Q_max= 40l/min; N_dv=0.37kW; h_max=38m; В=220V; n_ayl=3000 rpm/min according to GOST-2757030-91), rotometer 24 (RS-5; scale indicators in the range 0÷100; GOST-13045-81 according to) and a beaker tank (full volume 3.2 l) was selected for taring. Liquid consumption and speed were determined using the volumetric method for the diameter of the nozzle hole d_sh=3 mm. For this, the filling time of the beaker tank was determined according to the 0÷90 indicators of the rotometer [6,7,8,9,10,14,17].

In the experimental determination of liquid consumption, each experiment was repeated 5 times, and the square dimensions of each point and the resulting errors were determined. When the rotometer scale indicators changed from 0÷90, the liquid consumption changed to Q=0.071÷0.189 m³/h. The consumption change in each indicator increased in steps of 0.044 m³/h.

Centrifugal type, Pitot-Prandl tube, for determining dust gas speed, consumption and resistance coefficients of the working bodies of the device (Work efficiency Q_max=1000 m³/h; electromotive power N_dv=0.7 kW; rotation frequency n=1200 rev/min) 18 (50 and 100 mm size)). Metal pipe with D=60 mm, L=1000 mm, which determines the speed of dust gas. The pipe has 2 Pitot-Prandl tubes with an inner diameter of 7 mm, which determine the static and dynamic pressures. The Pitot-Prandl tube was selected according to the gas velocity, efficiency and pressure St requirement of the fan outlet diameter. In addition, in order to compare the obtained results, the ANEMOMETER VA06-TROTEC, which determines the gas velocity (the error coefficient is 0.2% in the measuring range 1.1÷50 m/s when the gas speed exceeds 50 m/s, the error coefficient is up to 5%) brand digital electronic meter was used. In order to control the speed of dusty gas, a louvre forming an angle of 100;300;450;600;900 was installed on the suction nozzle of the fan. Using the determined parameters, the resistance coefficient of the device and the hydraulic resistance of the device were determined. The experiments were carried out in two stages [11,12,13,15,17].

Experiments RD 34.20.519-97 "Ispytaniya hydravlicheskogo soprotivleniya truborovodov. Mashiny i apparatus dlya izmereniya rashoda gasov i davleniya. Programma i metody ispytaniy" [2,13].

Research of hydraulic resistance in the following limits of variable factors, the diameter of the liquid nozzle d_sh=3 mm, the liquid consumption Q_liq=0.071÷0.189 m³/h, the intermediate step increased by 0.021 m³/h, the diameter of the plate flange hole d_f=2, 3 and 4 mm, the angle of installation of the plate roller to the device β = 15^o; The number of 30^o and 45^o plates is 2 according to the angle of installation, the intermediate step was increased by an average of 5.5 m/s to the gas speed υ_g=7.4÷28.8 m/s. In the experiments, gas density ρ_g=1.29 kg/m³ for air and ρ_g=3.38 kg/m³ for the mixture of air and superphosphate mineral fertilizer dust as a dust gas (in which the amount of gas and dust mixture is 2697.79 mgr in 1 m³ of air). Taking into account the influence of the external environment during the experiments, the temperature for the water and gas system was set at 20 ℃±2.

STEP 1

Depending on the above variable parameters, resistance coefficients and hydraulic resistances were determined for the case where no liquid was supplied to the apparatus. In this case, the density of the gas supplied to the device was determined as ρ_g=1.29 kg/m³, and for the mixture of gas and dust, ρ_g=3.38 kg/m³. The experimental results are presented in Table 1 and Figure 4.

Table 1.

The coefficient of hydraulic resistance in the apparatus depending on the diameter of the hole of the spherical plate df and the angle of installation of the plate on the apparatus φchange

Figure 4. Graph of change of hydraulic resistance depending on gas velocity
a-When the mounting angle of the plate to the apparatus is φ = 15°; b-When the mounting angle of the plate to the apparatus is φ = 30°;v-When the mounting angle of the plate to the apparatus is φ = 45°. 1-ρ=1.28 kg/m³ and d_f=4mm; 2- ρ=1.28 kg/m³ and d_f=3mm; 3- ρ=1.28 kg/m³ and d_f=2mm; 4- ρ=3.38 kg/m³ and d_f=4mm; 5- ρ=3.38 kg/m³ and d_f=3mm; 6- ρ=3.38 kg/m³ and d_f=2mm

It can be seen from the comparison graphs in Figures 4 a,b and v that the gas density ρ=1.29 kg/m³ υ_gas=7.4÷28.8 m/s when the intermediate step increases with an average of 5.5 m/s and the mounting angle of the plate to the apparatus is respectively φ = 45°, 30° and 15° and plate hole diameter d_f=4, 3 and 2 mm when the low load of hydraulic resistance was ΔP_gaz=42 Pa, and the high load of hydraulic resistance was ΔP_gaz=1206 Pa. The change in gas density to ρ=3.38 kg/m³ caused an increase in hydraulic resistance. For example φ = 45°, 30° and 15° and plate hole diameter d_f=4, 3 and 2 mm when the low load of hydraulic resistance was ΔP_gaz=110 Pa, and the high load of hydraulic resistance was ΔP_gaz=3100 Pa. That is, depending on the change in gas density, the hydraulic resistance increased by 2.57 times. The following empirical formulas were obtained using the method of least squares for the graphic dependences presented in Figures 4 a, b and v [2,13].

y = 0,6701x² + 3,3122x - 21,741                 R² = 0,9992          (1)

y = 0,8836x² - 1,105x + 9,6121                   R² = 0,9994          (2)

y = 1,097x² + 2,7489x - 16,817                   R² = 0,9999          (3)

y = 1,7845x² + 6,8501x - 41,907                 R² = 0,9998          (4)

y = 1,9917x² + 8,7252x - 54,706                 R² = 0,9997          (5)

y = 2,1534x² + 28,056x - 171,64                 R² = 0,9987          (6)

y = 0,6176x² + 4,7268x - 26,988                 R² = 0,9997          (7)

y = 1,0112x² - 4,2606x + 30,582                 R² = 0,9996          (8)

y = 1,223x² + 0,2168x + 1,2952                 R² = 0,9998          (9)

y = 1,254x² + 25,725x - 157,38                   R² = 0,9976          (10)

y = 1,9336x² + 11,981x - 68,76                   R² = 0,9999          (11)

y = 3,5194x² - 10,16x + 70,544                   R² = 0,9998          (12)

y = 0,6348x² + 8,8413x - 54,089                 R² = 0,9986          (13)

y = 0,9142x² + 4,1915x - 25,643                 R² = 0,9998          (14)

y = 1,1834x² + 10,325x - 74,223                 R² = 0,9961          (15)

y = 2,2412x² + 6,4463x - 39,437                 R² = 0,9999          (16)

y = 2,4948x² + 4,5939x - 14,46                   R² = 0,9993          (17)

y = 3,9548x² - 7,9187x + 55,935                 R² = 0,9995          (18)

In the second stage, the resistance coefficient was determined for the case where liquid was supplied to the device depending on the variable parameters in the device. In this case, the density of the gas supplied to the device was determined as ρ_g=1.29 kg/m³, and for the mixture of gas and dust, ρ_g =3.38 kg/m³. The results of the experiment to determine the coefficient of hydraulic resistance are presented in Table 2.

Table 2.

Change of hydraulic resistance in the device depending on the liquid consumption Q and the angle of installation of the plate to the device φ

From the data in Table 1, it can be seen that the change in the diameter of the valve hole and the increase in fluid consumption cause an increase in the hydraulic resistance in the device. An increase in hydraulic resistance in the device leads to an improvement in cleaning efficiency. But an increase in resistance causes an increase in the amount of energy spent on the process. therefore, it is important to achieve high cleaning efficiency with low energy consumption and small hydraulic resistance.

Summary

• the coefficient of resistance of the working bodies of the structure at different sizes of the hole diameter of the spherical plate was determined;
• hydraulic resistance of the structure at different values ​​of the resistance coefficient was determined.
• the effect of fluid consumption on the resistance coefficient was considered.
• it was determined in the experiments that the hydraulic resistance of the scrubber with a spherical plate is 1.7 times lower than that of the existing structure.

References:

1. Исомидинов А. С., Тожиев Р. Ж., Каримов И. Т. Хўл усулда чангли газларни тозаловчи роторли курилма. Фаргона политехника институтининг илмий-техник журнали //Фаргона, (1). – 2018. – С. 195-198.
2. Исомидинов А. С. Разработка эффективных методов и устройств очистки пылевых газов химической промышленности: Дисс.… PhD //Ташкент,–2020.–118 с. – 2020.
3. Исомидинов А. С. Исследование гидравлического сопротивления роторно-фильтрующего аппарата //Universum: технические науки. – 2019. – №. 10-1 (67). – С. 54-58.
4. Тожиев Р.Ж., Каримов И.Т., Исомидинов А.С. Чангли газларни ҳўл усулда тозаловчи қурилмани саноатда қўллашнинг илмий-техник асослари: Монография. Фаргона политехника институтининг илмий-техник журнали //Фаргона, – 2020. – 91 б.
5. Мадаминова Г. И., Тожиев Р. Ж., Каримов И. Т. Барабанное устройство для мокрой очистки запыленного газа и воздуха //Universum: технические науки. – 2021. – №. 5-4 (86). – С. 45-49.
6. Исомидинов А.С., Тожиев Р.Ж., Каримов И.Т. Чангли ҳавони тозаловчи ротор-фильтрли аппарат фильтрловчи тўрли материалининг актив ва пассив юзаларини аниқлаш. I Международной научно-практической конференции “Актуальные проблемы внедрения инновационной техники и технологий на предприятиях по производству строительных материалов, химической промышленности и в смежных отраслях”. 2019/5/25. Т-3. №5. 429-431б.
7. Вальдберг А.Ю., Николайкина Н.Е. Процессы и аппараты защиты окружающей среды. – М. : Дрофа, 2008. –239 с.
8. Исомидинов А. С. Исследование гидравлического сопротивления роторно-фильтрующего аппарата //Universum: технические науки. – 2019. – №. 10-1 (67). – С. 54-58.
9. Rasuljon T. et al. Research of the hydraulic resistance of the inertial scrubber //Universum: технические науки. – 2021. – №. 7-3 (88). – С. 44-51.
10. Домуладжанов И. Х., Мадаминова Г. И. Вредные вещества после сухой очистки в циклонах и фильтрах //Universum: технические науки. – 2021. – №. 6-1 (87). – С. 5-10.
11. Исомиддинов А. С., Давронбеков А. А. Исследование гидродинамических режимов сферической углубленной трубы //Universum: технические науки. – 2021. – №. 7-1 (88). – С. 53-58.
12. Isomidinov A. S., Madaliev A. N. Hydrodynamics and aerodynamics of rotor filter cleaner for cleaning dusty gases //LI international correspondence scientific and practical conference" international scientific review of the problems and prospects of modern science and education". – 2018. – С. 29-32.
13. Кобзарь А.И. Прикладная математическая статистика. Для инженеров и научных работников. – Москва: Физматлит, – 2006. – 816 с.
14. Выгодский М.Я. Справочник по высшей математике. – Москва: Наука, 1972. – 872 с.
15. Isomidinov A. Mathematical modeling of the optimal parameters of rotory filter apparatus for wet cleaning of dusty gases //International journal of advanced research in science, Engineering and technology. – 2019. – Т. 6. – №. 10. – С. 258-264.
16. Isomiddinov A. et al. Application of rotor-filter dusty gas cleaner in industry and identifying its efficiency //Austrian Journal of Technical and Natural Sciences. – 2019. – №. 9-10. – С. 24-31.
17. Ergashev N. A. et al. Hydraulic resistance of dust collector with direct-vortex contact elements //Scientific progress. – 2021. – Т. 2. – №. 8. – С. 88-99.
18. Tojiev R. J., Sulaymonov A. M. Comparative analysis of devices for wet cleaning of industrial gases //Scientific progress. – 2021. – Т. 2. – №. 8. – С. 100-108.