Is there a pungent smell at the production site of your asphalt mixing plant? In natural gas-fueled mixing plants, asphalt smoke is the most important air pollution emission, which is closely related to the prevention and control measures adopted by production equipment. How to prevent and treat the asphalt fume generated during the production process of the asphalt mixing plant? There are several ways to solve it.
Incineration
Asphalt smoke is led from the finished product warehouse to the burner, and the air induction system sucks the asphalt smoke into the flame of the burner. The collected smoke is ejected from the annular air duct of the burner and enters the air duct evenly at the flame in the drying cylinder.
The most effective collection method at the discharge port is to set up a passage with a rolling door at the discharge port. By installing control components at the discharge port, the asphalt fume is collected through the adjustment and control of the wind deflector.
Adsorption collection
1. Static electricity
Asphalt flue gas passes through the primary channel, and the asphalt smoke particles are ionized by the high-voltage DC electrode to carry negative charges. After entering the secondary channel, the hydrocarbon particles are adsorbed by the positive electrode and separated from the air flow, and the processed air flow is directly discharged into the atmosphere. Electrostatic precipitator electrodes should be cleaned regularly to eliminate particle accumulation.
2. Media filtration
After bituminous smoke is sucked into the filter system, a part of the smoke is first condensed and flows into the storage tank, and the remaining smoke enters the secondary filter. The first stage preliminarily filters the condensate droplets, the second stage oil mist filter acts as a bitumen smoke filter, and the filtered smoke is discharged into the atmosphere by the fan. Usually used to collect smoke particles, not suitable for high concentration of fine particles. In order to ensure the normal operation of the adsorption device, the filter element needs to be replaced frequently.
3. Powder coated tobacco
Similar to the bag filter, the powder-coated smoke filter device adds fiber material to the pipe of the asphalt smoke to make it fully mixed with the asphalt smoke, and then is removed by the bag filter. The powder-coated smoke filter device adopts three filtering methods: impact, interception and Brownian diffusion. Impact refers to the collision of asphalt smoke particles with the filter. This method is effective for particles larger than 3μm; interception is used to collect small particles in the range of 1-3μm; Brown diffusion is used to collect submicron particles. The principle is: under the action of the air flow, the sub-micron particles produce Brownian motions such as whirling and translation along the arc-shaped trajectory, and collide with the filter fiber to be collected, thereby being removed from the air flow. The powder coating method requires regular replacement of the filter to meet the pressure difference requirements of the dust collector.
Low-temperature plasma flue gas purification method
In the low-temperature plasma asphalt flue gas purification technology, there are mainly three principles and functions of high-voltage pulse high-energy electron radiation, ultraviolet light decomposition and ozone oxidation. This technology can well destroy the macromolecular structure in the asphalt flue gas and generate small molecular substances. Under the action of ozone, the plasma collides with the molecules in the asphalt flue gas, so that the high-energy electrons generated in the plasma structure are excited to a higher energy state, forming excited state molecules, breaking the chemical bonds of the internal structure of hydrocarbons to form active substances, and the final product It is CO2 and H2O.
UV photocatalytic oxidation purification method
The UV photocatalytic oxidation purification method has a strong ability to decompose asphalt flue gas molecules and can efficiently remove volatile organic compounds (VOCs), especially for some malodorous gases, the deodorization efficiency can reach more than 99%. The principle of UV photocatalytic oxidation purification method is to decompose the molecular chain structure of VOCs, benzene, toluene, xylene and other organic substances or inorganic polymer malodorous compounds into small molecular structures, atoms and intermediates under UV ultraviolet light irradiation. , And then transformed into low-molecular compounds, such as CO2 and H2O under the action of nano-catalyst.
Condensation method
The methods for discharging the bitumen fume at the bitumen tank are as follows: One is to use a steam recovery device, which condenses the bitumen fume from the tank and discharges it into the asphalt pipe. The second is to treat the asphalt smoke in the asphalt tank with a condenser. The exhaust condenser itself is composed of several circular fin tubes. The asphalt smoke is condensed and concentrated and discharged back into the tank. The purified air is discharged into the atmosphere through the vent.
