Study of dust collection effectiveness in cyclonic-vortex action apparatus

The object of research is the efficiency of dust collection of fine dust in an apparatus with an intense turbulent mode of phase interaction. One of the most problematic areas of the existing dust and gas cleaning equipment is the low efficiency of collecting fine dust. Effective cleaning of exhaust gases from dust involves the use of multi-stage cleaning systems, including wet and dry dust cleaning devices, which entails high capital and operating costs. These disadvantages are eliminated in the developed design of the cyclone-vortex dust collector with two contact zones. The device implements both dry and wet dust collection mechanisms, which allows for high efficiency of dust removal at high productivity. The conducted studies of the total and fractional efficiency of dust collection when changing the operating parameters of the developed device showed that the efficiency of collecting fine dust is 98–99 %. The increase in the efficiency of dust collection in the dry stage of the device is due to an increase in centrifugal force. In the wet stage of contact, the efficiency reaches its maximum values due to the vortex crushing of the liquid in the nozzle zone of the apparatus. Studies of the fractional efficiency of the apparatus show that with an increase in the diameter of the captured particles, the efficiency of the dust collection process for dry and wet stages, as well as the overall efficiency, increases. With an increase in the density of irrigation, the overall efficiency of dust collection in the apparatus increases. It has been established that an increase in the efficiency of capturing highly dispersed particles occurs due to turbulent diffusion, the value of which is determined by the frequency of turbulent pulsations and the degree of entrainment of particles during the pulsating motion of packed bodies. To describe the results obtained, a centrifugal-inertial model for a dry contact stage and a turbulent-diffusion model of solid particle deposition for a wet contact stage are proposed, which make it possible to calculate the dust collection efficiency of the contact stages, as well as the overall efficiency of the cyclone-vortex apparatus. The results obtained show the prospects of using devices of this design at heat power plants and other industries.

PROBABLE ESTIMATION OF FRACTIONAL EFFICIENCY OF AEROSOLS COLLECTION IN THE BOUNDARY LAYERS OF MULTIPURPOSE SURFACES IN POWER PLANT

The probabilistc assessment of fractonal collecton efciency of aerosol in the boundary layers of the multfunctonal mesh surfaces is proposed.

ON THE QUESTION OF AIR VELOCITY AND PRESSURE IN AN INERTIAL CONCENTRATOR

Various designs of inertial concentrators for cleaning dusty air are considered. The analyzed designs of devices for separating dust particles by fractions also have a number of disadvantages: low fractional efficiency and complexity of structures when divided into several fractions. The design of an inertial dust concentrator with adjustable parameters is proposed. This design of the concentrator provides an increase in fractional efficiency and a decrease in hydraulic resistance with the simplicity of the apparatus design. Three-dimensional modeling of the spatial motion of air in an inertial dust concentrator with adjustable parameters is performed. A system of equations describing gas-dynamic flows is given. The results of calculations of velocity and pressure in an inertial dust concentrator with adjustable parameters are presented. Reflecting vanes and a false wall inside an inertial concentrator act as deflectors, that is, deflect the flow, which leads to an increase in the time spent by suspended particles in the inertial concentrator and a decrease in their kinetic energy. In this case, the role of inertia forces on the motion of particles will increase. Numerical modeling of the three-dimensional air flow in the concentrator made it possible to obtain a flow pattern and the main flow characteristics (velocity and pressure) from the moment of air supply to the concentrator to the moment of establishing the flow.

Analysis of the Behavior of a Metallic Filter in Particle Removal under High Pressure Conditions

This study aimed to examine the behavior of different filter media used in gas filtration at high pressure. Trials were carried out having phosphate concentrate as the particulate matter and compressed air as fluid. Operating conditions were evaluated at the following absolute pressures of the system: 193, 393 and 693 kPa, and the gas velocity was kept constant at 0.05 m/s. The results indicated that, for a given pressure drop at the filter, the highest absolute pressure applied to the system (693 kPa) yielded the highest powder mass deposited on the filter medium. An analysis of the porosity of dust cakes revealed that the increase in pressure resulted in cakes which were more porous and less resistant to gas flow. It was also verified that the increase in the pressure of the system provided an increase in the fractional efficiency of the filters for particles smaller than 5 μm.