Process for reclaiming ammonia-contained sewage

Abstract

A process for treating and recovering the ammonia / ammonium contained waste water generated in preparing catalyst includes reverse-osmosis concentration of the said waste with low ammonia content, direct use of the resultant liquid or partial use of it as the ammonia vapour absorbing liquid in stripping tower, mixing the concentrated liquid with the high-concentration the said waste water, adding alkali to regulate pH value, loading in stripping tower to recover ammonia from tower top and discharging the clean water. Its advantages include low energy and chemical consumption, and high recovery rate.

Description

technical field [0001] The invention relates to a method for treating and recovering ammonia / ammonium-containing process wastewater, especially for the treatment method of ammonia / ammonium-containing process wastewater generated in the catalyst preparation process, especially for the preparation process of oil refinery catalysts. A treatment and recovery method for ammonia / ammonium-containing process wastewater discharged from colloidal ammonium exchange and washing. Background technique [0002] Most of the oil refining catalysts are made of certain chemicals containing aluminum and silicon as raw materials, such as water glass, aluminum sulfate, aluminum hydroxide, aluminum silicate, etc., which are synthesized into NaY colloid or NaY molecular sieve through gelation and crystallization, and then passed through Na is exchanged by ammonium exchange or rare earth ammonium exchange process, etc. + ions, and wash out Na with chemically purified water (deionized water) + ions...

AI Technical Summary

Problems solved by technology

However, the proposed new process, like all ammonia / water membrane separation processes, needs to convert the ammonium in the wastewater into ammonia. Therefore, considering the economics of the process technology, it is generally only suitable for small amounts of concentrated ammonia-containing wastewater. deal with

[0004] There are also other physical and chemical methods for treating ammonia-containing wastewater, such as: US4285830 proposes to process the ammonium nitrate-containing wastewater produced in the nuclear industry by thermal decomposition and oxidation, and use HNO 3 and O 2 Oxidize ammonia or ammonium in wastewater to generate NO x , and then absorb it with nitric acid. This treatment method has great limitations and can only be used for the treatment of specific ammonia-containing wastewater, and cannot be used for the treatment of catalyst ammonia-containing wastewater; US4292043 proposes to use evaporation concentration and crystallization process to treat sulfuric acid. Ammonium sulfate is recovered from ammonium wastewater, but for catalyst ammonia-containing process wastewater, this evaporation concentration and crystallization treatment process can only be applied to the deammonization treatment of concentrated ammonia-containing process wastewater with relatively low wastewater volume, and due to the concentration of catalyst Ammonia-containing wastewater contains not only high concentration of ammonium, but also a considerable amount of Na + Ions, and some wastewater is often a mixture of various ammonium, such as ammonium chloride, ammonium sulfate, ammonium nitrate, ammonium phosphate, etc. If the treatment process of evaporation concentration and crystallization is adopted, the ammonium salt obtained will contain a large amount of impurities Mixture with ammonium, no recovery and reuse value

[0005] For low-concentration ammonia-containing wastewater that does not need to be recycled, biological treatment technology can be used for purification treatment, but the valuable ammonia components cannot be recovered, and it is difficult to recycle because the treated water contains salts and other impurities

[0006] To sum up, the technology for treating high-concentration ammonia-containing wastewater in the prior art is relatively mature, but for ammonia-containing wastewater with a lower concentration, especially for the treatment of a large amount of acidic ammonium-containing wastewater, the energy consumption of the existing treatment technology is high, Large consumption of chemical reagents, poor recycling of purified water

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