The dust ultrasonic atomization technology does not need to extract the dusty airflow and then treat it, which can directly suppress the dust generation point of dust and avoid the influence of dust removal factors. At the same time, due to the fine droplets, the amount of water used is less than one-thousandth to five-thousandths of that of the dust-inhibiting material, so the process flow is not affected. In addition to the simplified dust removal management work, the dust suppression technology does not require cleaning, and secondary pollution is avoided, thereby improving the working conditions of the dust removal management personnel. The dust suppression system occupies a small space, which saves the effective space in the plant and reduces the capital investment. The dust suppression system does not require fans, dust collectors and ventilation ducts, which saves 30% to 50% of the investment in the general dust removal system, and the installation time can be reduced by 70%. Compared with general dust collectors, dust suppression technology can save 50% energy consumption and greatly reduce the cost of dust removal operations.
First, the principle of ultrasonic atomization and dust removal
Ultrasonic atomization technology was developed in the 1980s as a new dust removal technology. The principle is to use the influence of the compressed air cavity to generate ultrasonic waves. The ultrasonic waves atomize the water into fine droplets with a diameter of only 150 μm. The droplet dust is confined to the local production capture point, and the fine dust is condensed, so that the dust settles rapidly and falls. Local dust removal. Ultrasonic atomizing dust collectors require water as well as many other dust removal technologies, but super-natural atomization has a distinctive feature. The basic principle is mainly aerodynamics.
According to the principle of aerodynamics, the dust-containing airflow bypasses the droplets, and the deviation of the collision of dust particles around the droplets of the inertial stream is captured, that is, by inertial collision, intercepting dust particles and droplets, thereby realizing capture, capturing is a The process associated with the diameter of the droplet. When the droplets are large, the dust particles are simply not trapped by bypassing the droplets. When the droplets are close to the particle size of the dust particles, it is easier to collide with the dust particles to collect the dust. Ultrasonic atomization is the application of this principle to produce droplets with similar fine particle sizes to capture dust.
When the ultrasonic water mist is sprayed into the dust space, because the size of the ink droplet is small, it can be evaporated in a short period of time, the water vapor in the spray area is rapidly saturated, and the supersaturated water vapor condenses a large amount of dust particles in the dust. , suspended in the area, and then began the microphysical process of cohesion and merger. This is mainly due to the temperature and concentration changes caused by the phase change of water and the formation of cloud droplets. In addition, the dusty air movement caused by the spray stream causes the cloud droplets carrying the dust particles and other water mist particles to collide with each other, coagulate and increase. Heavy sinking, forming a 'rain' to land. In addition, due to the condensation of water vapor on the surface of the respirable dust, not only the hydrophilic property of the dust is improved, but also the volume and weight of the dust are increased, which all contribute to the dust collection. This mechanism is particularly effective in suppressing submicron and micron dust.
For fine water mist to capture respirable dust, dust and mist have very small particle size, and respirable dust generally has poor wettability. Such a conventional method is difficult to achieve high-efficiency capture, and it is necessary to use some These measures are used to increase the probability of collision and solidify the particles into larger particles, which is beneficial to achieve sedimentation separation. According to the conditions required for the suspended particles to contact each other, the particles are generally coagulated by various means such as condensation condensation, dynamic coagulation and sedimentation.
Condensation and condensation. The mechanism of fine water mist dust collection shows that the condensation of water vapor is based on suspended particles, and the occurrence of condensation also causes uneven temperature and concentration changes in the dust collection space, which creates conditions for particle sedimentation. Condensation is a comprehensive process of coexisting multi-faceted coagulation mechanism, which mainly includes steam condensation and concentration gradient, temperature gradient condensation. Power condenses and settles. Dynamic coagulation refers to the process of relying on external forces to make the various particles in the dust-containing zone merge with each other. It is the application of this dynamic coagulation mechanism to spray water mist in the dusty space and to collect dust particles. In this case, the water droplets either rely on inertial forces or rely on self-gravity, diffusion, etc. to condense with dust particles in the dust-containing zone.
Second, ultrasonic atomization dust removal efficiency
When the water mist particles have a certain moving speed, the water mist particles are dusted by the combination of the inertial collision mechanism, the intercepting dust collecting mechanism, and the Brownian diffusion mechanism. The smaller the droplet diameter, the larger the Stokes number. The higher the trapping efficiency of inertial collision, the higher the density and particle size of the dust particles, and the higher the relative velocity of gas and liquid. On the other hand, the higher the number of water mist particles, the higher the efficiency of atomization and dust removal. The number of water mist particles can be compared with the liquid to gas ratio from a macroscopic point of view. Ultrasonic atomization and dust removal system has a dust removal efficiency of more than 90% in a small range of steam to water ratio. Compared with the traditional spray, the steam-water ratio is more than 10 times smaller, which indicates that the ultrasonic atomization dust removal system uses less water.
Third, the advantages of ultrasonic atomization dust removal technology
Save water consumption; follow-up processing equipment is simple, easy to handle and transport; fine water mist is good for respiratory dust capture; save operating cost Ultrasonic atomization technology has good trapping effect on inhalable particulate matter, and traditional spray dust removal technology In comparison, the efficiency is increased from 35% to over 80%. In addition, it has the advantages of low water consumption (0.1% of traditional water consumption) and simple follow-up treatment, and has broad application prospects in the control technology of inhalable particulate matter.