| 摘要 |
<p>Solvents evaporated from ink solutions in the drying sections of a multi-station printing press can be converted into harmless carbon dioxide and water vapor by heating the dryer exhaust for a given time period above a given oxidation temperature. The amount of energy required to maintain the oxidation temperature is substantially reduced by preheating the solvent laden exhaust through the use of a pebble bed heat generator prior to introduction of same into the oxidation chamber. If gases containing a sufficient solvent concentration level are preheated above the solvent ignition temperature, the solvent itself will provide heat of combustion sufficient to maintain the oxidation process. With this degree of preheat, at high solvent concentration levels, not only is no additional fuel required, but excess heat is generated. In order to maintain the system at minimum fuel consumption and eliminate the excess heat generated which is detrimental to operation of the oxidation chamber, a portion of the preheat section is bypassed by a selected amount of the exhaust such that the temperature in the oxidation chamber may be regulated. Alternatively, the solvent concentration level of the exhaust can be lowered by mixing the dryer exhaust with the floor sweep exhaust (of substantially lower solvent concentration) in regulated proportions. The latter method has the advantage of providing floor sweep capability without increased cost. Further, the use of solvent concentration (LEL) controls in the dryer sections can enhance the accuracy of the concentration control at the oxidation chamber and substantially reduce the size of the chamber by reducing the volume of exhaust to be processed.</p> |
