Resourceful treatment method and treatment system for LED-MOCVD ammonia-containing waste gas

Abstract

The invention discloses a resourceful treatment method for LED-MOCVD ammonia-containing waste gas. A membrane treatment method is used for resourceful treatment on the LED-MOCVD ammonia-containing waste gas. The method comprises the following steps: filtering the waste gas to remove impurities, and performing acid spraying absorption on the waste gas to remove ammonia gas so as to obtain an ammonium sulfate solution; and adjusting the pH value of the ammonium sulfate solution to 10-12, allowing the ammonium sulfate solution to enter a hydrophobic membrane system for deep deamination, and allowing the deaminated sulfate solution to enter a bipolar membrane electrodialysis system for acid-base regeneration, wherein the total recovery rate of ammonia gas is greater than or equal to 99.5%, soresourceful treatment is realized. By means of the treatment method, ammonia resources in the LED-MOCVD ammonia-containing waste gas are recycled in the form of electronic-grade high-purity ammonia, the ammonia recovery rate is larger than 99.5%, the purity of recovered ammonia gas is larger than 99.99999%, secondary pollution is avoided, and recycling and harmless treatment of the ammonia-containing waste gas are truly achieved.

Description

technical field [0001] The invention belongs to the field of waste gas resource treatment, and in particular relates to an LED-MOCVD ammonia-containing waste gas resource treatment method and a treatment system thereof. Background technique [0002] The exhaust gas produced by the LED epitaxy technology prepared by MOCVD (metal organic chemical vapor phase epitaxy) is relatively harmful, and the exhaust gas mainly contains N 2 、H 2 , NH 3 , a small amount of metal ions, particles, arsine, methane, water, carbon monoxide, carbon dioxide, oxygen and other impurity components, etc., need to be treated before they can be discharged. The commonly used methods generally include combustion method, water absorption method and acid absorption method. [0003] The combustion method decomposes ammonia into hydrogen and nitrogen by heating the catalyst bed. h 2 and NH 3 The ignition point and the combustion concentration range of the mixture are quite different, and the combustion...

AI Technical Summary

Problems solved by technology

However, the water absorption method cannot handle H 2 , and there is still ammonia smell in the tail gas treated by this method, there are certain limitations

The acid absorption method usually uses dilute sulfuric acid and NH 3 Perform neutralization reaction to generate ammonium salt aqueous solution. This method has better effect, but neutralization needs to consume a large amount of acid, and the cost of treating ammonium salt wastewater is very high

In view of the high purity and high price of the gas used in the MOCVD process, the use of the above treatment methods will cause waste of available gas in the tail gas, and will also bring new environmental problems

[0004] Chinese patent application number 201210244528.4 proposes a MOCVD tail gas recovery method, which uses an adsorption bed of alkaline earth metal chloride to adsorb ammonia gas, condenses it into liquid ammonia, and then carries out rectification and purification through a rectification tower. The hydrogen is vented, resulting in a waste of raw materials; and the use of rectification tower rectification treatment requires multiple purifications to obtain the target product, and the production cost is relatively high

[0008] Due to the complex components in the waste gas, the above-mentioned treatment methods for direct pressure swing adsorption or separation of ammonia from ammonia-containing waste gas have relatively long process flow, high energy consumption, high operating cost, and relatively low recovery rate of ammonia gas.

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