A system and method for ammonia-based flue gas desulfurization

Abstract

The present invention relates to an ammonia method flue gas desulfurization system and a method thereof. The ammonia flue gas desulfurization system comprises a desulfurization device (100), a slurry dust removal device (200) and an ammonium sulfate extraction device (300), wherein the desulfurization device (100) and the slurry dust removal device (200) form a dust removal circuit through a dust-containing slurry conveying pipeline (11) and a clear liquid reflux pipeline (12), and the desulfurization device (100) and the ammonium sulfate extraction device (300) form an ammonium sulfate extraction circuit through an ammonium sulfate slurry conveying pipeline (13) and a mother liquor reflux pipeline 14). According to the present invention, raw flue gas is desulfurized in the desulfurization device to form purified flue gas, one part of the generated dust-containing ammonium sulfate slurry is subjected to circulation dust removal through the slurry dust removal device, and the other part is treated with the ammonium sulfate extraction device to obtain the by-product ammonium sulfate crystal; and compared to the system and the method in the prior art, the system and the method of the invention have advantages of high desulfurization efficiency, high quality of the by-product ammonium sulfate, reliable system operation, and the like.

Description

technical field [0001] The invention belongs to the technical fields of chemical industry and environmental protection, and in particular relates to an ammonia flue gas desulfurization system and method. Background technique [0002] Acidic gaseous harmful substances contained in the flue gas of boilers and steel sintering plants, especially SO 2 , is the main source of acid rain. As we all know, an effective way to solve acid rain pollution is flue gas desulfurization. [0003] Ammonia desulfurization technology using ammonia as desulfurizer, its by-product is a kind of ammonium sulfate fertilizer with high fertilizer efficiency, which can realize SO in flue gas 2 recycling of resources. However, in addition to gaseous pollutants, flue gas also contains more solid dust. In addition, ammonia desulfurization is a wet desulfurization method. Most of the process water used will contain various metal salts, such as calcium, magnesium, iron, aluminum carbonate or sulfate, whi...

AI Technical Summary

Problems solved by technology

The problem with this technique is that during the process of ammonium sulfate nucleation and crystal growth, due to the persistent presence of dust or slag, it will still be adsorbed on the surface of small crystals or fine crystals, pollute the crystal surface, and block new solute molecules Transmitted from the solution to the surface of the crystal, thus preventing the growth and continuous growth of the crystal, it is difficult to solve the problem of producing a large number of fine crystals

On the other hand, since the ammonium sulfate extraction process uses a centrifuge, the ammonium sulfate crystals with fine particles will enter the mother liquor through the filter screen. If the slurry used for dust removal is drawn from the mother liquor tank and directly enters the filter, there will be more More ammonium sulfate crystals are filtered out by the dust collector, which is easy to block the filter and cause more ammonium sulfate loss

Patent 201120290949 and Patent 201210081856 announced the dedusting system of ammonia desulfurization, which is the technology of ammonium sulfate extraction after dust removal, which is mainly suitable for the extraction of ammonium sulfate by evaporation and crystallization, because after filtration, the solution is clear liquid without crystal sulfur For ammonium, only the method of evaporation and crystallization is used to extract ammonium sulfate, which requires a large investment in equipment, high steam and power consumption, and poor economic efficiency.

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