Environmental Monitoring Foundry Industry Air Pollutant Emission Monitoring
The foundry industry refers to the manufacturing industry that produces various metal castings, which can be divided into ferrous metal casting and non-ferrous metal casting. The metal charge is transformed into a molten state by heating, and the casting mold is manufactured. After solidification, a metal with a certain shape, size and performance is obtained. The forming method of parts blank is applied to various industrial furnaces such as cupola, electric arc furnace, gas furnace, induction furnace, holding furnace, Jing smelting furnace, etc. in the casting process, involving molding, core making, pouring, falling sand, sand treatment , waste sand regeneration, casting heat treatment and surface coating processes, and then produce particulate matter, VOCs, SO2, NOX and other pollutants, in order to do a good job of environmental monitoring of air pollutants in the foundry industry, monitor and control emissions according to the type of pollutants Work.
According to the content of the “Emission Standards for Air Pollutants in the Foundry Industry”, the relevant departments have stipulated pollutant emission limits for each process process, such as molding, core making, pouring, falling sand, sand treatment, waste sand regeneration, casting heat treatment and surface treatment. The emission limit of particulate matter in coating and other processes should not exceed 30mg/m3, among which the emission limit of SO2 in sand treatment and waste sand regeneration should not exceed 150mg/m3, the emission limit of NOX should not exceed 300mg/m3, and the emission limit of SO2 in heat treatment of castings The value should not exceed 100mg/m3, and the NOX emission limit should not exceed 300mg/m3. For the emission limit of air pollutants of combustion devices, SO2 and NOX should not exceed 200mg/m3.
Distinguish between organized pollution discharge and unorganized pollution discharge control requirements. Organized pollutant discharge is usually discharged through the chimney mouth, and it can be effectively controlled after purification treatment in each process link. Install monitoring equipment such as dust online monitor and micro air quality monitor for pollution monitoring.
Discharge of fugitive pollutants is relatively complex and difficult to monitor. Material storage, material transfer and transportation, and casting can all produce a large amount of particulate pollution. The storage, transfer, and surface coating of VOCs materials will produce VOCs pollution. Therefore, it is necessary to install monitoring instruments at the dust-generating point, boundary, and factory area. Deploy fugitive dust online monitors, VOCs online monitors, and miniature air quality monitors, and take measures to control fugitive pollution emissions.
The prevention and control measures for unorganized particulate matter and VOCs pollution include the following: powdered materials such as pulverized coal, bentonite, and silica sand should be bagged or canned, and stored in closed storage or semi-closed stockyards (stack sheds); hardening, and take measures such as regular cleaning and watering to keep it clean; the dust discharge port of the dust collector should be covered and other dust suppression measures; paint, resin, curing agent, thinner, cleaning agent and other VOCs materials should be stored in airtight containers, Packaging bags and storage; containers or packaging bags containing VOCs materials should be stored indoors, or in a dedicated site with canopies, shading and anti-seepage facilities.
