| 摘要 |
<p>The parent patent describes a process in which ClO2 is produced from tail gases contg. among them Cl2, by (a) contacting the gas mixt. with an excess of reducing gas or liquid, in the presence of water in an auxiliary reduction reactor, to reduce almost all the Cl2 in the tail gas to HCl; (b) passing at least part of the product, into a prodn. reactor and contacting it with 7-11 (8-10N) alkali chlorate in H2SO4 medium at 25-60 degrees C to form the ClO2. Another part of reduced gas leaving the redn. step is passed into a secondary reactor and contacted with effluent liquid leaving the second step at 70-80 degrees C to reduce the Cl2 content; the gas leaving step (b) is passed through water at 0-10 degrees C to dissolve out the ClO2 forming an aq. soln. (e) recycling the gas remaining. In addition patent, the main reduction reactor is of the counter-current gas-liquid type in which a counter current between the reduced tail gas contg. the excess reductant introduced into the base of the reactor, recycling in part the liquid leaving the base to realise the dilution of the reactant introduced after cooling the effluent liquid. A counter current contact is arranged in the principle reactor and in the secondary reactor and part of the liquid leaving the bottom of the principal reactor is recycled after cooling to the top of the reactor to dilute the incoming reactant. Also, part of the gaseous effluent from the secondary reactor may be recycled pref. after heating to 70-80 degrees C to the top of the main reactor dispersing it finely at the level convenient for equilibrating the pressure. The efficiency and distribution of the gas-liquid mass exchanges are improved by increasing the concn. gradients thus favouring the desired exchanges.</p> |
