Fabric Filter gas cleaning system (Bag Filters – Bag House) comes in two variants: Pulse Jet Bag Filter and Reverse Air Bag House catering to particulate emission control or product recovery in applications of boiler, furnace, kiln, mill, and material handling. Thermax products are capable of handling more than 100 types of particulate matters.
Reverse Air Bag House
The Reverse Air Bag House (RABH) is a customized-built filter, designed for cleaning gases with typically high flow rates (from 60.000 m3/hr to more than 10.800.000 m3/hr) and high temperature suitable for various industrial processes.
The typical Thermax RABH is modular in construction, with four or more independent modules. The sealed air gap between the modules adds to the insulation to increase the operating economy. The extra space created by the hoppers provides a large passageway between rows down the middle of the system. This passageway is divided into three sections horizontally to make the inlet plenum, outlet plenum, and the reverse-air plenum.
This construction and operation of the units not only offer control on velocity profiles but also facilitate on-line maintenance. Each module can be isolated for inspection or maintenance by closing the inlet, outlet and reverse air damper, while other modules are in operation.
Pulse Jet Bag Filter
Pulse Jet Bag Filter with filter bags of a length of more than 6 meters is equipped with a pulsing system, an innovation patented by Thermax, which delivers benefits of reduction in compressed air consumption, maintaining the differential pressure, saving in power consumption of the ID fan and facilitating the capacity enhancement of the existing Bag Filter.
Dust cleaning method:
– Online Pulse Jet Bag Filter: In an online bag filter, bags are cleaned row by row, even while the dust-laden gas is filtered concurrently. The sequence of cleaning is controlled automatically by a sequence controller.
– Online Pulse Jet Bag Filter: It incorporates the advantages of a Pulse Jet Bag Filter as well as that of a Reverse Air Bag House. Each compartment is similar to an online pulse jet bag filter. The cleaning process consists of sequentially isolating each compartment and then cleaning the isolated compartment with compressed air. Offline cleaning is suitable for light and fine dust, and with large gas volumes.
Cage with Integral Venturi
Bag Filters Advantages and disadvantages
• Bag filters are constant emission devices. When the inlet dust load even slightly increases, the outlet emissions remains constant
• Bag filters are used for very fine dusts, and where the dust is not wet or having a caking tendency.
• Bag filters have lower capital investments
• Bag filters need lower foot-print area.
• Periodic replacement/maintenance cost is high.
• Bag filters operate with a constant pressure drop of approximately 150 – 175 mmWC. Hence required fan power is high.
• Bypass at higher temperature (> 240 Deg C).
• Need continuous maintenance