Oxidation of volatile organic compounds (v.O.C's) in an air stream (fumes) before discharge to the atmosphere is likely the most cost effective way to treat organic fumes. However, in applications where air is not very dirty and contains only one or two particular solvents, solvent recovery by activated carbon adsorption may be cost effective because of the value of reused solvent.Enders offers incineration either thermal or catalytic both with indirect heat recovery, or the former with thermal regenerative heat recovery. If the fume to be treated is dirty it may foul preheaters' tubes and make heat recovery difficult. If no heat recovery is to be considered and particularly if the fume is hot (i.E. Hot fume discharging a curing oven) the catalytic incinerator might be the better choice since it requires the lowest amount of preheat. Preheating the fume to 650of or 750of will likely be all that is required and a direct fired gas/oil burner can be used for that. A thermal incinerator, on the other hand, will require about double that temperature as a minimum. Combustion chamber volume must be such that fume residence time is ½ second minimum at 1400of minimum. These conditions are for v.O.C's (in air) which are easiest to destroy. Treating v.O.C's in air which is more difficult to oxidize completely requires higher temperature and/or residence time. Because of high combustion chamber temperature, heat recovery (heating the incinerator incoming fume with heat from outgoing gas) is required. A tubular heat incinerator is shown with incoming fume flowing on inside of tubes (surface easiest to clean). A burner brings the fume to combustion chamber temperature before it enters the chamber. Incinerator can incorporate either "thermal regenerative exchange" or "indirect heat exchange".
With indirect heat recovery; fume flows (may be dirty) through the inside of exchanger tubes (more easily cleaned) and preheating it with hot, clean flue gas discharging the incinerator and flowing on the outside of the tubes; with "thermal regenerative" heat recovery; hot clean gas, discharging the incinerator flows through a bed of "ceramic stones" and then, when stones get hot, switch to flowing fume through the same bed there-by preheating the fume.
