Clean-blow cycle

Dust emissions occur during both the end-of-cycle purge sequence and especially the subsequent clean-blow cycle (required to clean out the tanker). Note ... 

Fabric-filter systems, commonly called bag-filter or bag-house systems, are dust-collection systems in which dustladen air is passed through a bag-type filter. The bag collects the dust in layers on its surface and the dust layer itself effectively becomes the filter medium. Because the bag s pores are usually much larger than those of the dust-particle layer that forms, the initial efficiency is very low. However, it improves once an adequate dust-layer forms. Therefore, the potential for dust penetration of the filter media is extremely low except during the initial period after startup, bag change, or during the fabric-cleaning, or blow-down, cycle. 

In 1974, F. Sherwood Rowland and Mario Molina, who shared the 1995 Nobel Prize in Chemistry with Crutzen, showed that chlorine from photolyzed chlorofluorocarbons (CFCs) such as CF2C12 and CFCI3, which were used as supposedly inert refrigerants, solvents for cleaning electronic components, plastic foam blowing agents, and aerosol spray propellants, can also catalyze ozone loss. Subsequently, the chlorine monoxide molecule CIO, which is involved in the chlorine-catalyzed ozone destruction cycle, has been shown to be present in the holes in the ozone layer and to correlate inversely with... 

Bag filter batch load cycle and clean intermittent shaking, reverse pulse, reverse blow ring or sonic cleaifing. Load filter until the gas pressure drop across the filter is >1.5 kPa, then clean. Choice of fabric is critical static charge on fabric, operating temperature, potential for fumes to absorb with moisture to deteriorate bag, and need to select dust removal option to keep the Ap across the bag of 0.5 to 1.5 kPa. Felted material gives higher gas flow rate per unit area than woven, costs 3 to 4 times more, and cannot be cleaned by... 

A self-cleaning cycle can be performed by a timing mechanism, using compressed air blown in short bursts through horizontal blow pipes into the filter chamber. This brief pressurization causes the accumulated particles to become dislodged from the filter elements. The dust is then pulled by a separate air fan into a secondary cleaning circuit, which exhausts the particles to the atmosphere away from the inlet... 

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