Treatment method for abandoned dichlorodifluoromethane

Abstract

The invention relates to a treatment process for abandoned dichlorodifluoromethane. The process comprises the following steps: (1) mixing zirconium sulfate, titanic acid and tungstic acid according to a mole ratio of zirconium to titanium to tungsten of 1 to (0.5-0.6) to (0.1-0.3), adding water for granulating, and performing spray-drying at 200-300 DEG C to prepare catalyst granules with the diameters of 0.1-10 mm; (2) putting the granules into a tubular reactor, wherein the volume of the catalyst granules accounts for 25-40% the total volume of the tubular reactor; (3) introducing dichlorodifluoromethane and steam into the tubular reactor according to a volume ratio of 1 to (3-6), keeping the temperature of the tubular reactor at 250-300 DEG C, and controlling the contact time to be 3-10 minutes; (4) absorbing the steam by 90-98% concentrated sulfuric acid for tail gas after catalytic hydrolysis, absorbing hydrogen chloride gas by absolute ethanol, absorbing hydrogen fluoride gas by a sodium hydrogen carbonate solution, and absorbing carbon dioxide gas by a sodium carbonate solution. Compared with the prior art, the process has the characteristics that the energy consumption is low, the dichlorodifluoromethane hydrolysis efficiency is high, and a hydrolysis product can be reutilized. Therefore, the process has a wide application prospect in the field of waste treatment and resource.

Description

technical field [0001] The invention relates to the field of environmental protection, in particular to a method for treating waste freon. Background technique [0002] Freons (CFCs) are "safe refrigerants" synthesized in the 1920s. It has many characteristics such as good chemical stability, easy phase change, non-corrosion and high insulation, so it is widely used in various fields of modern production and life. The CFCs emitted into the atmosphere are very stable in the troposphere and can exist stably for tens to hundreds of years. However, after they slowly rise into the stratosphere, they will be decomposed under the action of strong ultraviolet rays, and the chlorine atoms released by the decomposition are the same as ozone A chain reaction will take place, destroying the ozone molecules. According to scientific estimates, one chlorine atom can destroy tens of thousands of ozone molecules. The ozone layer on the earth's surface can absorb ultraviolet rays in solar ...

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Problems solved by technology

[0006] 2. Greenhouse effect

Chinese patent (CN201110320425.7) discloses a method for treating waste freon by hydrothermal decomposition. Lye, oxidant, and freon are put into the reaction system together for hydrothermal reaction, and the hydrolyzed product of freon is immediately absorbed by the lye. Migmatite containing carbonate and fluorine and chlorine is finally obtained, which has the characteristics of fast and efficient reaction, but has the disadvantage that the product is mixed salt, which has little economic value and has not been fully utilized; Chinese patent (CN200810058719.5) discloses a Freon combustion A method for improving the decomposition rate of Freon in the hydrolysis process, but the decomposition efficiency of CFCs cannot reach complete (98%), and dangerous secondary compounds will be produced; the published patent (CN1049295) describes a catalytic decomposition method of chlorofluoroalkanes, which The method not only has the problem that the catalyst is easily deactivated, but also the efficiency of its catalytic decomposition of Freon needs to be further improved; the chemical reagent digestion method has the problem of dealing with residual chemical reagents; Chinese patent (CN200810058719.5) discloses a microwave plasma decomposition of Freon Harmless treatment method, the decomposition efficiency of Freon can reach more than 99%, and good results have been achieved, but this method is prone to carbon deposition in equipment, and the stability of operation needs to be improved

[0009] For the treatment of Freon, most of them are treated by combustion method, which makes Freon burn at about 800-1200°C. Other methods such as microwave decomposition method and plasma method are also being studied, but the cost of microwave decomposition method and plasma method is too high. New pollutants will be produced, and effective substances cannot be recovered, resulting in waste of resources

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