Direct-fired combustion equipment

Direct-fired combustion equipment is that in which the flamt of combustion are used to achieve the desired result by r and convection. Common examples include rotary kilns and open-hearth furnaces. Indirect-fired combustion equipment is that in wh e... 

Auxiliary Equipment On direct-heat rotating equipment, a combustion chamber is required for high temperatures and finned steam coils are used for low temperatures. If contamination of the produc t with combustion gases is undesirable on direct-heat units, indirect gas- or oil-fired air heaters may be employed to achieve temperatures in excess of available steam. 

Steam Generator Produces steam from condensate or boiler feedwater by combustion of waste oil, tars, or off-gas in direct-fired equipment. 

After beneficiation, the washed rock may contain 7%-20% moisture, which is reduced to between 1% and 2% moisture using direct-fired rotary dryers. Emissions expected from the dryer consist primarily of fine rock dust. Some sulfur dioxide may also be present in the dryer exhaust from the combustion of sulfur in the fuel. Phosphate rock dryers are usually equipped with dry cyclones, followed by wet scrubber systems for control of rock dust. The scrubber systems will operate at typical particulate collection efficiencies of 97%-98% with emissions ranging from 0.1 to 0.3 kg/t of phosphoric anhydride (P2O5) [77]. 

Fuel-fired (combustion type) furnaces are most widely used, but electrically heated furnaces are used where they offer advantages that cannot always be measured in terms of fuel cost. In fuel-fired furnaces, the nature of the fuel may make a difference in the furnace design, but that is not much of a problem with modem indusfrial furnaces and combustion equipment. Additional bases for classification may relate to the place where combustion begins and the means for directing the products of combustion. 

Maintenance of combustion safety controls on direct-fired equipment... 

Burning Equipment for Pulverized Coal, The burner is the principal component of equipment for firing pulverized coal. Coal must be pulverized to the point where particles are small enough to assure proper combustion (Table 6.15). In the direct-firing system the coal is dried... 

In the composite boiler, a watertube chamber directly connected to a single-pass shell boiler forms the combustion space housing the fluid bed. In order to fluidize the bed the fan power required would be greater than that with other forms of firing equipment. 

Provisions should be made to direct flammable or combustible liquid spills away from fired heaters. Spills from other equipment that flow into or under fired heaters can and have been ignited by the hot surfaces or flames of fired heaters. Conversely, in the past, spills from ruptured tubes in process heaters have allowed burning liquid to flow around and damage other equipment. Both process heaters and nearby equipment should be protected from each other due to possible spills of flammable or combustible liquids using one of the following methods ... 

A major fire erupted in a nonflammable solvents manufacturing unit in a U.S. Gulf Coast chemical complex. A furnace tube in a natural-gas-fired heater ruptured due to overheating. At least 1,800 gallons (6,800 liters) of a combustible heat transfer fluid spilled and burned intensely. Within about 25 minutes, the intense hot fire damaged four levels of structure and associated process equipment. The plant on-site emergency squad quickly and properly responded. However, the price tag for short-lived incident was over 1.5 million in direct property damage and over 4 million in business interruption (U.S. 1979). Fortunately, there were no injuries. [2]... 

DISPOSAL AND STORAGE METHODS may be disposed of in a secured, sanitary landfill recommended method of disposal is incineration, preferably after mixing with another combustible fuel incinerator should be equipped with an acid scrubber, necessary to remove the halo acids produced should be stored in tightly closed containers in a cool, well-ventilated place, away from areas of high fire hazard and out of direct rays of sun avoid contact with strong oxidizers, since violent reactions occur. 

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