Asphalt Mixing Industry

Asphalt Industry

A hot mix asphalt plant produces asphalt paving mix, which may include natural sand, crushed limestone, slag, gravel, oyster shells, decomposed granite, crushed rock, hydrated lime, Portland cement, or other non-plastic mineral matter (collectively called aggregates), depending on the specific grade requirement. After mixing, the hot paving mixture is loaded into trucks, and transported to the paving site for construction. Transportation costs are an important cost factor, and for this reason, the industry is composed of a large number of asphalt plants located close to points of utilization. It is estimated that there are more than 3,500 hot mix asphalt plants in the United States alone.

Hot mix asphalt plants are normally located within city limits or in highly urbanized areas, and the associated dust problems are of concern to authorities, the general public, and plant operators. Air pollution control ordinances are now being adopted worldwide, many with specific regulations aimed at this particular operation, and no new plant is installed today without specific provisions for dust emission control. In addition, the growing demand for asphalt paving mixture materials means that more than average effort has to be expended in controlling dust emissions.

Dust Collection Challenges

At a hot mixing asphalt plant dust sources are the drum dryer, hot aggregate elevator, vibrating screens, hot aggregate storage bins, weigh hopper, mixer, and truck loading. Among them, the largest dust emission source is the drum dryer, where aggregates are dried and mixed with asphalt cement. The dust ladden gas flow generated during the drying and mixing of aggregates has the following characteristics:

• High volume and velocity
• Abrasive and alkali corrosive
• Variable composition depending on the source of the raw materials
• Fine particles
• High temperature
• Moisture at elevated temperature

This dust can pose significant health and environmental risks if not properly managed. Therefore, dust collection is a critical aspect of maintaining an asphalt plant, as it ensures the safety and efficiency of the production process.

To overcome the dust collection challenges at asphalt plants, plant operators have to invest in high-quality filter bags that are specifically designed to handle the unique demands of asphalt production.

Filter Bags for Asphalt Plants

Baghouses are still the most commonly used filtration solution to meet the emission control standards in the industry. They can be of the reverse air, pulse jet, or even shaker style.

Aokai specializes in making filter bags that fit and work perfectly with asphalt plant equipment from all major brands, such as Ammann, Marini, Benninghoven, Nikko, Lintec, Astec, Parker, Tarmac, and KVM. We are the OEM supplier of filter bags to some of these brands, and the after-market or replacement filter bag supplier to all these brands.

Aokai uses the highest quality fabric raw materials from the most reputable suppliers (e.g., Teijin Conex, and DuPont Nomex). Focusing on industry-specific emission control requirements, our asphalt mixing plant filter bags have the following advantages:

• Reduced dust emissions
• Increased filter bag life due to improved abrasion and corrosion resistance
• Increased energy efficiency due to reduced cleaning
• Sustainable production capacity due to increased airflow capacity

Filter Media and Filter Bags for Asphalt Plants

Aokai baghouse filter media and filter bag products that are most commonly used in Asphalt Plants: