Application and reformation of dry fog dust suppression technology

Li Xiaokun [1] Shao Ting [2] LI Mingliang [3]

[1] Baotou Iron & Steel Co., LTD. Warehouse, Baotou 014010, Inner Mongolia;

[2] Baotou Steel Group Co., LTD., Baotou 014010, China;

[3] Baotou Iron & Steel Group Co., LTD., Baotou 014010, China

Abstract: In this paper, dry fog dust suppression technology as the main research content, combined with the analysis of dust trapping mechanism, combined with relevant principles to understand that when the size of water mist particles are close to each other and the amount of fog is sufficient, the probability of collision and condensation will be increased. The wide application of dry fog dust suppression technology can effectively improve the efficiency of dust removal, and there will be no secondary pollution. It breaks through the constraints of seasonal use, and has obvious promotion and application value.

Keywords dry fog dust suppression technology application transformation research

CLC number: TD714 Document ID: A

With the development of modern industrialization, the level of automation has been improved significantly, and the application effect in many fields is very outstanding. Especially in the process of using heavy machinery and equipment, the increase of mining intensity will be accompanied by a significant increase in dust amount, which seriously affects human health. The application of dry fog dust suppression technology has obvious effect on dust control, so it is of practical significance to study and analyze the application of dry fog dust suppression technology.

Overview of dry fog dust suppression

1.1 Connotation

Dry fog refers to the application of a technology that effectively atomizes water into fine droplets with a particle size of no more than 10 microns. The outstanding advantage of dry fog is that it has a larger contact area with air and a higher evaporation rate, so that the water vapor in the dust-containing area can be saturated in a short time. It is because of the large amount of spray and small droplets, similar to "smoke", so it is also called dry fog.

1.2 Basic Principles

One, the principle of aerodynamics. When the dusty air flows around the fog droplets, the dust particles will deviate from the airflow and collide with the fog droplets and be captured. Specifically refers to in the case of dust particles and droplets collision, can achieve the capture target. However, there is a close relationship between the capture success rate and the force of dust and droplet diameter. In other words, the smaller the particle size of the water mist, the more viscous the particles will be. In the case of dry mist size, the particles are more likely to bond. In this way, the particles will gradually expand and settle, eventually achieving the goal of removing the dust particles.

Second, the principle of "cloud" physics. Due to the obvious microfineness of fog drops, some of them are easy to evaporate in the air, leading to the saturation of the relative humidity of the air in the closed dust collection space in a short time, and then gradually generate "clouds" through dust particles and decline in the form of "rain". In terms of dust, the rational application of the principles of "cloud" physics can continuously enhance the effect of sub-micron and micron dust. When the micron level dry fog dust suppression device is in working condition, fine dry fog will be formed inside the closed area immediately to ensure that the humidity of the air is saturated in a short time. Subsequently, the water vapor in the saturated state will contact with the dust and settle on the basis of condensation, finally achieving the goal of dust suppression.

Three, Stephen flow transport mechanism. In the process of using dry fog dust suppression technology, within the spray area, the droplets will reach the goal of evaporation as soon as possible. As a result, a concentration gradient composed of vapor forms inside the region surrounding the droplet, which flows outward and diffuses, eventually forming Stephan flow. In addition, on the basis of steam concentration and condensation in a core, the steam concentration around the core will decrease significantly, and then the Stephen flow in the form of condensation core movement will appear. In this case, the suspended dust particles inside the spray area will move under the influence of Stephan flow transport, contact and adhere to the condensed droplets, and finally be moistened and captured. It can be seen that after the dust in a certain region has achieved dry fog trapping and settling, the rest of the region with high dust concentration will be affected by the transport of Stephens flow and move, always colliding and contacting with dry fog, and finally achieving the goal of systematic trapping.

1.3 Advantages

On the one hand, resources, capital saving effect is obvious. Compared with wet dust removal technology, the actual water consumption of dry fog dust suppression device in the process of use is significantly reduced, only 1/1000 of the wet dust removal technology. At the same time, the increasing weight ratio of the material moisture is within the range of 0.02-0.05%, and there is no calorific value loss of the material. In addition, the application of dry fog dust removal device, the actual area is not large and convenient operation, through the application of PLC technology can realize the full automation of control. On this basis, the purchase price of dry fog dust suppression system equipment is not high, and the actual operation and maintenance cost is not high. In the long run, the probability of dust explosion will be significantly reduced, especially the investment of firefighting equipment.

On the other hand, the use of dry fog dust suppression equipment will not be affected by seasonal changes. The application of dry fog dust suppression device does not need to consider seasonal changes, even in winter can be used. The main reason is that the dry fog dust suppression device is advanced in technology, and the device is set inside the tropical zone, so the spray of dry fog will not condense into small ice drops in winter. In this way, the quality of dust suppression in winter will not be adversely affected. When the actual use temperature does not exceed 5 degrees Celsius, the insulation system inside the dry fog dust suppression device will start and run.

2. Practical application of dry fog dust suppression technology

At present, the application advantage of dry fog dust suppression technology has gradually emerged, and has been widely used in various fields. Taking the application of dry fog dust suppression technology in the overturning machine room as an example, according to the analysis report and the data information of the user's use report, it can be found that if the traditional wet dust removal method is used, the dust content per cubic meter can be guaranteed to reach 4.75mg. The average amount of dust produced by the coal unloading pond inside each rollover machine room can reach 10 tons every day. With 13 tipping units, the annual output of coal dust could reach 46,800 tons. If the calculation standard is 500 yuan per ton, the annual loss amounts to 23.4 million yuan. However, after choosing to use dry fog dust suppression technology device, the ability to control coal dust is significantly improved, more than 90%, then the annual reduction of coal economic loss is more than 20 million yuan. In addition, if the traditional wet dust removal method is used, and the number of cars discharged per year is 23,000 calculated, then the water spraying per train will be up to 20 tons. However, after the introduction of micron level dry fog dust suppression device, the actual spray volume will be significantly reduced, and the spray volume per train is only 2 tons. If the price of reclaimed water is 1 yuan per ton, the annual savings could reach 410,000 yuan.

Based on the analysis of the use effect of the dry fog dust suppression device, it is found that the indoor dust concentration of the dry fog dust suppression device in operation can be 3.977 mg per square meter. If the device stops running, the dust concentration per cubic meter can reach 5.733 mg, effectively improving the effect of dust suppression.

3 Closing remarks

In conclusion, the reasonable application of dry fog dust suppression technology can guarantee the prevention and control of inhalable dust, and can effectively enhance the effect of dust, and the economic, social and environmental benefits are significant, so it has certain promotion and application value.

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