Keeping dust emissions within the required limit
Existing electrostatic precipitators at the cement plant operated by Holcim Ecuador S.A. in Guayaquil were no longer technically capable of keeping dust emissions in the clinker cooler exhaust from both kiln lines within the required limit of < 30 mg/Nm3. Therefore, Holcim decided to invest in new dedusting equipment, choosing a bag filtration system equipped with EMC technology (Fig. 1) that was manufactured by Scheuch of Aurolzmünster/Austria.
Scheuch’s scope of delivery
The EMC filtration plants, equipped with 6-meter filter bags, were designed as row-type filters and dimensioned for 260 000 Am3/h and 310 500 Am3/h, respectively. To provide for cooling of the clinker cooler exhaust air before entry into the EMC bag filtration systems, the scope of delivery also included two air/air heat exchangers engineered to meet the following design (Tab. 1) and operating data (Tab. 2). In addition to the delivery of key parts (filter heads), radial fans, dust discharge devices (rotary valves, trough chain conveyor) and the emergency temperature valve system, Scheuch also supplied the engineering required for the local manufacture of structural steel work and pipe fittings. A Scheuch supervisor from Austria monitored the assembly of the equipment and assembly operations were carried out to the customer’s complete satisfaction.
Switchover in two days
The biggest challenge faced during the installation of this new equipment was that of minimizing downtime to the greatest possible extent during assembly in order to keep the shortfall in production as small as possible. Therefore, without disturbing kiln operations, Scheuch chose to install the first half of the row-type EMC filter for Kiln Line 1 and to operate this fully functional part of the filter during this short phase of the switchover period with an air-to-cloth ratio of 1.89 m/min, something possible only with Scheuch’s EMC technology. During this period, the electrostatic precipitator was disassembled and parallel to this, the second half of the EMC filter was assembled, connected to the crude gas side and put into operation. Only because of the clever planning and implementation by Scheuch was it possible to comply with the required switchover time of two days. The same principle was used during installation of the second EMC filtration system. This filter was also put into operation with absolutely no problems and was able to comply with guaranteed limits and provide the highest levels of operational availability, all to the customer’s complete satisfaction. www.scheuch.com
