Measures and plans for asphalt smoke control

Measures and plans for asphalt smoke control1、 The necessity of asphalt flue gas treatment.Asphalt smoke is prone to adhesion and is flammable and explosive above a certain temperature. During the collection, transportation, and smoke suppression process of asphalt smoke, it is easy to adhere to the surface of pipelines and equipment, forming liquid or even solid asphalt. Solid asphalt is difficult to remove, often leading to pipeline blockage, equipment damage, and system malfunction.In addition, the composition of asphalt smoke is very complex, as the sources of asphalt vary. Asphalt smoke not only contains solid and liquid particles condensed from the volatile components of asphalt, but also organic compounds in a vapor state. Some organic compounds are high molecular weight polymers that can cause serious environmental pollution. Smoke contains various organic compounds, including carbon cyclic hydrocarbons, cyclic hydrocarbon derivatives, etc., which are harmful to human health. Asphalt smoke contains polycyclic aromatic hydrocarbons such as benzopyrene, benzoanthracene, and carbazole, which are mostly carcinogens and strong carcinogens, posing a threat to human health. Its main pathway is to adhere to dust below 8um and inhale it into the body through the respiratory tract. Therefore, it is necessary to purify the asphalt flue gas to ensure that the emissions comply with atmospheric environmental standards.2、 Parameters of smoke control system.1. Determine the amount of flue gas.Based on the actual situation on site, collect on-site smoke production points and set up smoking hoods at each point to determine the distribution of system air volume.2. Governance objectives.Smoke emissions should comply with the second level standard limits of the Comprehensive Emission Standard for Air Pollutants (GB16297-1996), which means that the concentration of asphalt smoke is ≤ 40mg/NM3, and the concentration of benzo [a] pyrene is ≤ 0.3X10 ^ -3.3、 Key points of process flow and system design.Asphalt smoke is prone to adhesion and burns easily above a certain temperature. During the collection, transportation, and smoke suppression process of asphalt smoke, it is easy to stick to the surface of pipeline equipment to form liquid or even solid asphalt, which is difficult to remove and can affect the normal operation of the system. In addition, the main components of asphalt smoke are aromatic hydrocarbons and heterocyclic compounds, which can cause serious environmental pollution.According to relevant information, the performance of asphalt and asphalt smoke is as follows: asphalt self ignition point 610 ℃, lower explosive limit 35g/m ³， The maximum ignition energy is 40mJ, the maximum explosion pressure is 0.32MPa, and the average pressure rise rate is 2.5MPa/s. The critical oxygen content to prevent floating dust from being ignited by electric sparks is 16%.According to these data, the system needs to design high-pressure spray fire protection device and explosion-proof device. Based on relevant data and the characteristics of asphalt smoke, the design points are as follows:The optimal temperature for asphalt smoke collectors is 60 ℃ -80 ℃. If it is below 50 ℃, the asphalt is easy to bond, and if it is above 100 ℃, it is not easy to capture, which does not meet the process requirements of asphalt smoke collectors;2. Prevent asphalt from burning in the flue, and prevent open and hidden flames from entering the asphalt smoke collector;3. Minimize coal dust in the flue gas as much as possible and improve the fluidity of coal tar asphalt in the asphalt smoke collector;4. The asphalt smoke collector is equipped with explosion-proof devices;5. In order to solve the problem of large diameter and airflow deviation in electric capture equipment, an advanced diversion and gas distribution system must be installed at the bottom of the equipment.