Using the profiled elements to increase electrocyclone effectiveness 173 D O I: 1 0. 15 82 6/ ch im te ch .2 02 0. 7. 4. 06 Anton Trinkunas, Lidia Pomortseva, Anatolii Titov, Zalina Rusinova Chimica Techno Acta. 2020. Vol. 7, no. 4. P. 173–176. ISSN 2409–5613 Using the profiled elements to increase electrocyclone effectiveness Anton Trinkunas*, Lidia Pomortseva, Anatolii Titov, Zalina Rusinova Ural Federal University, 19 Mira st., Ekaterinburg, 620002, Russia *email: trinkunas.anton@yandex.ru Abstract. The article is devoted to flue gas cleaning, using fly ash as an example. Electrocyclone can be employed as gas-cleaning equipment. The electrocyclone opera- tion can be intensified by reducing re-entrainment. The laboratory model of the annular channel of the electrocyclone is used to show the possibility of reducing re-entrainment by using the shaped elements of various designs on the collecting electrodes. Aerosol industrial emissions can be reduced by using an electrocyclone with modified collecting electrodes. Keywords: gas treatment; re-entrainment; shaped elements; electrocyclone Received: 18.10.2020. Accepted: 07.12.2020. Published:30.12.2020. © Anton Trinkunas, Lidia Pomortseva, Anatolii Titov, Zalina Rusinova, 2020 Introduction Technological advancement im- plies a continuous increase in the capacities of industrial companies. Industrial enter- prises use solid materials for production purposes. Many of  the  thermal power stations supplying electricity to industri- al companies also operate on solid fuels. Increasing volumes of emitted flue gases require high-performance gas-cleaning devices [1, 2]. Aerosols can be purified in  various types of devices [3–5]. An electrocyclone is  a  combined dust collector that com- bines the centrifugal and electrostatic ef- fects for cleaning aerosols. There has been unreasonably little focus on the  electro- cyclone research. A comprehensive study of this type of gas cleaning devices could lead to the introduction into the industry of a new type of highly efficient gas clean- ing devices. It is  possible to  intensify the  opera- tion of  electrocyclones by  optimising the various parameters and characteristics. The main of this is reduction of re-entrain- ment [6]. This work is devoted to the inten- sification of the work of the electrocyclone by reducing re-entrainment. The effective- ness of the profiled elements of different shapes is considered. Experimental For visual observation and quantifi- cation of the effectiveness of the profiled elements, a stand was assembled. A sche- matic diagram of the experimental stand is shown in Fig. 1. The stand is designed as a prototype (in a first approximation) of the annular channel model. 174 The  stand consist of: 1 is  the  corona electrode, 2 is  the  external collecting electrode, 3 is the internal collecting elec- trode, 4 is  the  body, 5 is  the  collector, 6 is  the  inlet pipe, 7 is  the  exhaust pipe, 8 is the glass plate, 9 is the settling chamber. The walls (smooth aluminum plates) were connected to the positive pole of an exter- nal source of high voltage and grounded. The  discharge electrodes are connected to the negative pole of the external high- voltage source. 4 most common structural elements were selected (Fig. 2): C-shaped element (a), double C-shaped element (b), rounded C-shaped elements (c), Z -shaped elements (d). Re-entrainment is associated with ejec- tion of the entrapped materials on the col- lecting electrodes. Fig. 3 shows a top view of the settling chamber with a besieged ash layer. It can be seen that on the deposited layer there are jagged areas. The photo taken from the side shows that the  largest number of  holes are op- posite the fixed points of the corona dis- charge. The same can be said about other areas. In  all cases, the  observed jags are opposite the  corona electrode, namely in front of the needles located thereon. The shape of the holes is irregular, and they do not form a  perfect cone or any spherical/elliptical surface. Such an irregu- lar shape of the edge and surface of holes due to large particles hitting the material layer at an angle rather than strictly in a ra- dial manner. Numerous traces of particles in front of the fixed points of the corona discharge can be attributed to the high concentra- tion of  charged ions moving to  the  col- lecting electrode and the  greater inten- sity of  the  electric field in  that domain. A larger concentration of ions and larger electric field strength contribute to increas- ing the maximum possible charge as well as  more intense particle charging. This increases the rate of the large particles mi- gration to the collecting electrode by a few to a few dozen times. Fig. 1. A stand for the re-entrainment process study Fig. 2. Profiled elements 175 The  second part of  the  study was the visual and partly quantitative evaluation of the installation of profiled elements on the external collecting electrodes of the an- nular channel. Photographs of the profiled elements placed in the model of the active area channel with ashes settled on them are shown in Fig. 4. The ash was deposited on the surface of the collecting electrodes and the surface of the profiled elements. Moreover, the ash was on the outside and inside surfaces of the profiled elements. Ash distribution on the  external col- lecting electrodes is the same in all cases. Parts of low spots of the Z-shaped profiled elements are covered by  a  thicker layer of material, although there were areas not covered with ashes due to partial shielding of the corona discharge. Visually, the ash lay- er thickness on the electrodes seemed larger in all cases of the profiled elements, while the thickness of the layer on the smooth set- tling electrode without any elements seemed to be thinner. On the stand the dust col- lection efficiency was also quantitatively studied in the presence of the profiled ele- ments in the active area channel. Evaluated was the amount of material accumulated on the collecting electrodes by passing a sample of 50 g of ash (Table 1). It is  shown that the  most effective (13.8 g per 1 element) are double C-shaped elements; the lowest efficiency is demon- strated by C-shaped elements along the gas (13.0 g). Z-shaped ones catch only 11.3 g and the  rounded C-shaped ones catch 5.6 g. This can be explained by the devel- oped parasitic vortices in the radial cavity of the blades and between the blades. Anyway, the  profiled elements can reduce re-entrainment. This happens through the  removal of  large particles of the aerosol flow path due to delays and deposition and at expense of conservation on the surface of the particle layer in view of the wind shadow. Fig. 3. Photograph of the deposited material layer. Channel without the profiled elements Fig. 4. C Photograph of the deposited material layer. Channel with the profiled elements 176 Conclusions Some research was conducted in a gas treatment process of  the  annular chan- nel model of an electrocyclone. To assess the effectiveness of the profiled elements, an experimental stand was manufactured and exploratory tests were conducted. The  design of  the  stand can be used for further experimentation. A technique of physical modeling of re- entrainment was tested. The effectiveness of the profiled elements was demonstrated qualitatively and quantitatively. The most effective are the double C-shaped profiled elements. References 1. Yan P, Zheng C, Zhu W, Xu X et al. An experimental study on the effects of tempera- ture and pressure on negative corona discharge in high-temperature ESPs. Applied Energy. 2016;164:28–35. doi:10.1016/j.apenergy.2015.11.040 2. Oh J, Choi S, Kim J. Numerical simulation of an internal flow field in a uniflow cyclone separator. Powder Technology. 2015;274:135–45. doi:10.1016/j.powtec.2015.01.015 3. Chen CJ, Wang LFS. Cost-benefit analysis of electrocyclone and cyclone. Resources, Conservation and Recycling. 2001;31:285–92. doi:10.1016/S0921-3449(00)00086–0 4. Zhuohan L, Shao C, An Y. et al. Energy-saving optimal control for a factual electro- static precipitator with multiple electric-field stages based on GA. Journal of Process Control. 2013;23(8):1041–51. doi:10.1016/j.jprocont.2013.06.007 5. Shrimpton JS, Crane RI. Small Electrocyclone Performance. Chemical Engineering & Technology. 2001;24(9):951–5. doi:10.1002/1521–4125(200109)24:9<951::AID–CEAT951>3.0.CO;2–9 6. Titov A. The impact of re-entrainment on the electrocyclone effectiveness. Separa- tion and Purification Technology. 2015;156(2):795–802. doi:10.1016/j.seppur.2015.11.004 Table 1 Comparative effectiveness of the profiled elements № Element type Collected ash mass, g Quantity of elements, piece Collected ash mass corresponding on 1 element, g 1 No elements 16.2 2 8.1 2 C-shaped 26.0 2 13.0 4 C-shaped double 27.6 2 13.8 5 C-shaped rounded 22.4 4 5.6 6 Z-shaped 34.0 3 11.3