Cementarnica USJE has installed state-of-the-art exhaust gas dedusting filters on both of its production lines. The production process is designed so as to prevent the lines from running without the filters being online, and all the exhaust gases coming out of the kilns, dryers and mills are purified in these bag filters before being released into the atmosphere. The filters installed in Cementarnica Usje are manufactured by Italy's Redecam and Austria's Scheuch respectively for each line.
The filters operate on the principle of extracting the exhaust gases with the help of negative pressure (vacuum), which means that the entire system is closed, and the main fan that pulls the gases is after the filter. The exhaust gases together with the dust enter the filter's lower chamber and pass through the bags. The dedusted air passes into the upper chamber of the filter (the so-called "clean-chamber"). The dust clings to the surface of the bags, which are made of a special material (fabric) that can withstand the high temperatures of the exhaust gases. The bags are cleaned by injecting high-pressure air into them at predetermined time intervals, for a fraction of a second, in order to remove (shake) the material from the surface of the bags. The material falls to the bottom part of the filter ("dust hopper") and is returned to the silos via conveying duct. The filter is divided into several chambers, which allows easy repair of any defects without taking the entire filter offline. According to the work method and the manufacturer's specifications, the bags are maintained, inspected and replaced at suggested intervals.
The filter's overall operation is automatically controlled by the CEMAT process software and monitored by operators in the control room.
These are the latest generation of filters for the cement industry. This type of filters and their mode of operation are listed in the Best Available Techniques (BAT) Reference Document for the Production of Cement, which comply with the European directives and national legislation.
