Dust suppression by misting systems in the mining and metallurgical industry
Industrial dust is formed as a result of transportation, processing and storage of materials containing a dust fraction in their composition, or a dust fraction is formed during processing (crushing, screening and transshipment).
In the mining industry, a significant amount of dust occurs during drilling and blasting operations, in the coal industry - during the operation of combine harvesters and loading machines, during the sorting and enrichment of coal. At concentrating plants, dust enters the air during crushing and grinding of rock.
Ash dumps, slag dumps of metallurgical plants and thermal power plants: a lot of dust gets into the air from open ore and coal warehouses in ports and mining enterprises.
The formation of a large amount of dust interferes with the efficient operation of enterprises, reduces the resource of equipment, attracts the attention of regulatory authorities and residents.
Fog suppression systems can be used to reduce the amount of emissions. Such systems supply fog to the dusting zone, fog particles stick to dust particles, weigh them down and lower them to the surface of the work site or dump.
Fog can be used both to suppress active dust sources during development (excavator buckets, blasting operations) or transportation and reloading (feeder bunkers, car dumpers, ship loaders), and to create a dense covering layer on the surface of dumps during storage. To enhance the effect, special binders or foam-forming surfactant solutions can be added to the sprayed water.
Two main approaches are used to create a dust suppression area — the installation of stationary or mobile fog guns with powerful fans and the design of modular fog generation systems with nozzles.
The guns are delivered ready assembled and immediately ready for use, only connection to water and electrical power is needed. Modular systems are designed based on the specific requirements of the customer separately for each dusting source, taking into account the nature of dust and seasonality of operation.
The principle of operation of dust suppression systems
Dust suppression systems create a large concentration of the smallest water droplets with a diameter of up to 10 microns (with the possibility of adding surfactants), which trap small suspended particles and smaller particles.
Superficially active substances stick to suspended dust particles, increasing their weight and attracting them to the ground. Dust suppression systems effectively cope with inhaled dust particles of 0.1–1000 microns in size: dust trapped in a thick water mist simply has nowhere to go.
The modules of the system are installed in places where substances fall under the influence of gravity, where the highest concentration of harmful dust particles is fixed. Due to its modular structure, dust suppression systems are easily installed, which favorably differs from dust collection technologies that require modernization of premises, which significantly increases their cost and reduces flexibility in use.
Water spraying systems (with/without the addition of surfactants):
· Dust suppression systems are based on the technology of spraying water using nozzles.
· Surfactant additives contribute to better bonding of the water with dust particles, thus providing greater dust suppression efficiency.
· The percentage of moisture falling on the material is <0,7%
· These systems are not too demanding on the quality of the water in comparison with fog-forming systems, but for their long-term operation, at least a coarse filter is needed to avoid clogging of the nozzles.
Advantages of using the fog system in mining, metallurgical and processing enterprises:
1. Due to the small size of the nozzles and pipes, the system can be installed in close proximity to the dust-producing equipment;
2. The installation of the systems is very simple, so it does not require special projects or permissions. During the installation of the system, the factory continues to operate normally. Modification is not required;
3. The operation of the system is fully automated and does not require constant attention. Moreover, when the plant stops working, the system turns off, saving you money;
4. Thanks to its special design, the nozzles can be completely cleaned;
5. The required maintenance is minimal, and the components are not subjected to severe wear;
6. color:#2D2D2D;background:white">It can be used in warehouses and out-of-premises;
7. Surfactants are decomposed by microorganisms;
8. The amount of dust used for trapping is minimal, there is practically no residual moisture on the materials.
Using our systems, you no longer pay fines to environmental inspections and have no conflicts with the population, TV channels and local authorities.
Consider stationary and mobile fog systems in more detail.
Fog-forming equipment can be mounted on a stationary base, for example, on a column ("mast", if it is necessary to spray fog from above onto the treated area, preventing dust and odors from rising into the air, besides, when mist is sprayed from above, air flows that could raise dust are not formed), as well as on wheeled trolleys, truck bodies, on watering machines and even the boom of a telescopic loader.
Stationary misting systems are used in places of constant dust formation, for example, in the production of building materials, at the conveyor belt moving bulk materials, etc. Such systems consist of high-pressure pumps (up to 120 bar) pumping water into spraying nozzles (so-called "hydraulic", the pressure in which is 10-20 bar), the water is purified by filters, preventing clogging of injectors.
Specialists estimate that the use of fog generation systems in rooms in some cases is much more profitable than the use of ventilation: fog generation systems consume approximately 5% of the energy of a conventional ventilation system, and the cost of installing a fog generation system is only 40% of the cost of installing a conventional ventilation system.
The main elements of high-pressure misting systems are:
· high pressure pump,
· filters for water,
· high-pressure main and auxiliary pipelines,
· clamping,quick-release, threaded and reduction fittings,
· spraying nozzles,
· control unit of the spray system,
· fasteners, etc. accessories according to the project
Pushkipilepodavleniya – more mobile equipment, rathersuppression of dust and creation of "fog curtains" on large open construction sites or in quarries.
The "cannon" is a guide casing in which a powerful electric fan is enclosed. The nozzles are located along the circumference of the edge of the casing on a special ring. They generate billions of tiny water droplets, which are picked up by the air flow created by the fan. The ring can consist of separate sectors, the position of each of which is regulated separately, so the shape of the fog cloud can be adjusted according to need.
Using nozzles of different dimensions, shape, type of spraying and performance, with holes of different diameter, it is possible to select a mist for dust particles of any size and any working conditions. It is possible to install nozzles on swivel hinges to change the direction of the jet, as well as with water pressure adjustment, also to change the trajectory of the jet. All nozzles of this installation must be the same size in order to generate fog drops of the same size. The nozzles can be made of brass or stainless steel, easily dismantled and cleaned with a simple tool. The use of steel reduces wear and corrosion and ensures years of maintenance-free operation even when using poor quality water.
Some mistakenly believe that dust suppression is when rare jets of water are sprayed through the air with a large fan. This is absolutely not the case. Dust suppression is a whole science that includes the solution of many technical issues that allow achieving maximum efficiency at minimal cost.
Our fog generation systems offer highly efficient solutions for dust capture and suppression and air filtration at processing plants, quarries, coal warehouses and terminals, as well as all processes of its production.