Air-to-cloth ratio

Air-to-cloth ratio The unit capacity of a fabric filter, i.e., the total volume of gas in actual m Vs divided by the gross or net fabric area in m. ... 

Goodfcilow, H. D., R. J. Geren,, and E. F. C. Foord. Applications of Fabric Filters at High Air-to-Cloth Ratios on Metallurgical Fumes. In The User and Fabric Filtration F.qmpment 111, APCA Specialty Conference Proceedings, Buffalo, NY (Oct. 1-3, 1978). 

Suggested Air-to-Cloth Ratios for Dust Removal from Air Type of Dnst Ratio... 

Reverse-pulse filters are typically operated at higher filtration velocities (i.e., air-to-cloth ratios) than shaker or reverse-flow designs. Filtration velocities may range from 3 to 15 feet per minute in reverse-pulse applications, depending on the dust being collected. However, the most the commonly used range is 4 to 5 feet per minute. 

Environmental Considerations. The principal environmental problem is the prevention of particulate dust emission, which can be handled by cloth filtration equipment. Filtration of taphole fumes consisting of submicrometer particles, which rapidly dog the filtration media, is both difficult and expensive. Dust collectors operating at low air to cloth ratios are required. Dust created in material handling equipment is of relatively large particle size and easily handled by doth filtration. Treatment of the furnace CO gas stream is complicated by the high temperature of the gas, its explosiveness, toxicity, dust concentration, and partide size. 

It is proposed to install a pulse-jet fabric-filter system to remove particulates from an air stream. Select the most appropriate bag from the four proposed below. The volumetric flow rate of the air stream is 10,000 std ft3/min (4.72 m3/s) (standard conditions being 60°F and 1 atm), the operating temperature is 250°F (394 K), the concentration of pollutants is 4 grains/ft3 (141 grains/m3), the average air-to-cloth ratio is (2.5 ft3/min)/ft2, and the required collection efficiency is 99 percent. 

Baghouses are high-maintenance items due to internal movement in a dust-laden stream. They operate at low air-to-cloth ratios and the collectors are large and more costly than some other devices described in this section. 

A calcium hydroxide plant is required to treat the exhaust fume generated from the plant. The ash generated from the system is collected at the bottom of the baghouse while the exhaust gas flow of 350,000 acfm enters the baghouse with a loading of 6.0gr/ft. The air-to-cloth ratio is 8.0 and the operating particulate collection efficiency is 99.3%. The maximum allowable pressure drop is 10 in. H2O. The contractor s empirical equation for the pressure drop is given by... 

The size of a baghouse is primarily determined by the area of filter cloth required to filter the gases. The choice of a filtration velocity (or its equivalent, the air-to-cloth ratio (ACR or A/C) in actual cubic feet per minute of gas filtered per square foot of filter area) must take certain factors into consideration. Although the higher velocities are usually associated with the greater pressure drops, they also reduce the filter area required. Practical experience has led to the use of a series of ACRs for various materials collected and types of equipment. Ratios in current use range from <1 1 to >15 1. The choice depends on cleaning method, fabric, and characteristics of the particles. 

Calculate the total required surface area A of the bags if the air-to-cloth ratio is 8.0 ... 

The two design and operational parameters that determine fabric filter performance are air-to-cloth ratio and pressure drop. The air-to-cloth ratio is the volumetric flowrate of the gas stream divided by the surface area of the fabric. The higher the ratio, the smaller the baghouse and higher the pressure... 

Catalytic bag filter systems are used in the waste ineinerator sector. Cost data from this application are transposed on basis of the flue-gas volume to be treated, but without taking into account operational parameters such as air-to-cloth ratio. For a depreciation time of 5 years, the investment and operational costs can be estimated at EUR 0.4 - 0.5/tonne molten metal for HBC and EUR 0.9 - 1.3/tonne molten metal for CBC. This priee estimation was nor eonfirmed nor discarded by a catalytic bag filter supplier. 

Operational data are given in Section 3.2.3.4. Current bag filters have air to cloth ratios between 2 1 and 3 1. The air to cloth ratio is the ratio of volumetrie airflow through the filter to the... 

The actual size of a fabric dust collector will vary according to the volume of dust that has to be removed from a process in a given period of time. The velocity at which the dust is carried into the filter (sometimes referred to as the air-to-cloth ratio) is also a major factor in determining the total fabric surface area requirement. To give the reader some perspective as to the diversity of sizes, a filter may contain just a few sleeves in order to capture a small volume of nuisance dust, from say a woodworking shop, whereas in one of the largest fabric filters in the world, the Eraring Power Station in Australia, some 190 000 sleeves are used, with a total filtration area of over 500 000... 

Filters or other collection devices are required for all conveying systems. The reserve-jet air flow systems for cleaning the filter are very common units. For lower pressure, the air-to-filter cloth ratio is usually approximately 1.1 to 0.3 CMM/m (3.5 to 1.0 CFM/sq.ft). For higher pressure reserve flow systems, a higher air-to-cloth ratio is employed, 2.1 to 0.3 CMM/m (7.0 to 1.0 CFM/sq. ft). For more detailed discussions, see Chapters 22 and 28, Gas-Solids and Liquid-Solids Separation. ... 

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