High-efficient wet-type ammonia recovering method desulfuration method with oxidation and concentration processes outside tower and device thereof

Abstract

The invention discloses a high efficiency wet-type desulfurization method through ammonia recovery method for oxidation and concentration outside a tower, and a device thereof. The method comprises the following steps: (1) feeding flue gas into the top part of a concentrating tower after dust removal, cooling down and humidifying the flue gas, then feeding the flue gas into a first level venturi section of a desulfurization absorption system to contact atomized ammonia water so as to have the first level absorption reaction, performing the second level and the third level desulfurizations, and discharging the flue gas after the purification; (2) oxidizing the ammonium sulfite solution generated in a desulfurizing tower and then overflowing the ammonium sulfite solution into a mother liquor tank from the top part of an oxidation tank; and (3) pumping the ammonium sulfate solution in the mother liquor tank to the top part of the concentrating tower through a mother liquor pump to perform heat exchange with the high temperature flue gas after atomization so as to form a supersaturated solution containing 3 to 5 percent of crystal, wherein the supersaturated solution flows out of the bottom of the concentrating tower and is pumped into a hydraulic cyclone through a slurry pump to perform the first level solid-liquid separation, and then the clear solution automatically flows into the mother liquor tank; the crystal-liquid mixed solution flowing out of the bottom of the concentrating tower automatically flows into a centrifugal machine to perform the second level solid-liquid separation, and then the clear solution automatically flows into the mother liquor tank; and solid ammonia sulfate is fed into an automatic packaging machine to be packaged and put into storage. The method has simple processes, greatly reduces investment, and can reclaim agricultural level ammonia sulfate and industrial level ammonia sulfate.

Description

technical field [0001] The invention relates to a high-efficiency wet ammonia recovery method desulfurization method for external oxidation and concentration, and also relates to a high-efficiency wet ammonia recovery method desulfurization device, which belongs to the technical field of environmental protection. Background technique [0002] my country is a country where coal is the main energy source. Soot-type air pollution dominated by sulfur oxides and soot has always been dominant. It has become one of the countries with the most serious sulfur oxide pollution in the world. So far, there are many desulfurization methods. There are mainly two types, dry method and wet method. Ammonia desulfurization is one of the wet desulfurization methods. It uses ammonia-containing aqueous solution to contact flue gas to chemically absorb sulfur dioxide to generate ammonium bisulfite and Ammonium sulfite solution, and these two solutions are easy to decompose, easy to form secondary po...

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Problems solved by technology

[0002] my country is a country where coal is the main energy source. Soot-type air pollution dominated by sulfur oxides and soot has always been dominant. It has become one of the countries with the most serious sulfur oxide pollution in the world. So far, there are many desulfurization methods. There are mainly two types, dry method and wet method. Ammonia desulfurization is one of the wet desulfurization methods. It uses ammonia-containing aqueous solution to contact flue gas to chemically absorb sulfur dioxide to generate ammonium bisulfite and Ammonium sulfite solution, and these two solutions are easy to decompose, and it is easy to form secondary pollution during storage or transportation, which also makes it difficult for the product to be fully utilized

At present, the domestic ammonia desulfurization method is basically based on the technology of Masulai in the United States, and the method of oxidation and concentration in the tower is used for desulfurization and ammonium sulfate recovery. In the process of use, this method has the following problems: (1 ) Since the oxidation process and the enrichment process are carried out in the same desulfurization tower, the height of the tower body is increased, resulting in a very complex structure in the tower. At the same time, in order to solve the problem of safety maintenance during equipment operation, it is necessary to add emergency tanks and pipeline pump valves and other spare facilities. Increased construction investment and system operation and maintenance costs; (2) Due to the use of oxidation in the tower, the desulfurization system always operates under weakly acidic conditions, resulting in low absorption rate and increased energy consumption; at the same time, the corrosion is particularly serious, This makes the anti-corrosion requirements for equipment very high, which increases equipment investment and system operation and maintenance costs; (3) Oxidation in the tower uses violent gas bubbling oxidation, and the air cannot fully contact with the ammonium sulfite solution, so it is difficult to achieve Higher oxidation rate, in order to ensure that the ammonium sulfite product does not contain ammonium sulfite, the oxidation time must be increased to increase the oxidation rate, otherwise, the ammonium sulfide product has low purity, contains part of ammonium sulfite and a certain amount of smoke, and is used in fertilizers. When the ammonium sulfite is used, the ammonium sulfite burns the seedlings, which makes it difficult to promote the use of the product; (4) if the concentration is used in the tower, the ammonium sulfate agglomeration will be formed in the tower, which will easily cause blockage, affect the normal operation of the desulfurization system, and increase maintenance. cost

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