Method for producing thiosulfate and recovering carbon dioxide by utilizing industrial flue gas

Abstract

The invention relates to a method for producing thiosulfate and recovering carbon dioxide by utilizing industrial flue gas. The method comprises the steps of: contacting a bicarbonate solution serving as an absorption liquid with exhaust gas to absorb SO2 in the exhaust gas and to generate sulfite and carbon dioxide, adding enough sulfur to the generated sulfite solution, heating and boiling for reaction, then filtering, evaporating, cooling and crystallizing, and centrifugally separating to prepare a thiosulfate finished product. According to the invention, sulfur dioxide in the flue gas and inexpensive bicarbonate are utilized to produce an expensive thiosulfate product, the air is purified and the reutilization of sulfur resources is realized, the SO2 utilization rate is high, after purification, SO2 in the flue gas is almost completely removed, and the recovered thiosulfate and carbon dioxide have low cost and high quality; and any secondary pollution is not generated, thus the method for producing thiosulfate by utilizing industrial flue gas is a green and clean process technique capable of protecting environment and recycling wastes and has wide market prospects.

Description

technical field [0001] The invention relates to the technical field of environmental protection and production of chemicals, in particular to a method for producing thiosulfate by utilizing sulfur dioxide-containing industrial flue gas and recovering pure carbon dioxide. Background technique [0002] Sulfur dioxide is one of the main substances that cause air pollution and is very harmful to human health. my country has listed sulfur dioxide as a major air pollutant controlled by laws and regulations, and the concentration of sulfur dioxide in the atmosphere has been regarded as an important indicator for evaluating air quality. The sulfur dioxide in the industrial waste gas is the main component of sulfur dioxide in the air, therefore, the sulfur dioxide must be purified before the industrial waste gas is discharged into the air. [0003] The desulfurization methods used today generally use Ca(OH) 2 Calcium based method, Alkaline method based on NaOH, KOH, NH 3 based amm...

AI Technical Summary

Problems solved by technology

[0004] In calcium method, Ca(OH) 2 with SO in flue gas 2 and CO 2 reaction to generate CaSO 3 and CaCO 3 Two kinds of insoluble matter, these two kinds of insoluble matter precipitate together, and precipitate together with coal dust, become a large amount of waste slag accumulation, cause secondary pollution environment again, and Ca(OH) 2 As the temperature rises, its solubility decreases, it is easy to scale, and it leads to blockage of pipes and damage to equipment

[0005] Strong base absorption method is to use NaOH, KOH to absorb SO 2 Generate Na 2 SO3 or K 2 SO 3 , this method has a good effect, but the price of alkali is high, and it needs to consume a lot of electricity to make it, so it is expensive to use it in large quantities, and the source of medicine is difficult.

[0006] The ammonia water absorption method is to use ammonia water to absorb SO 2 , production (NH 4 ) 2 SO 3 , its disadvantage is that it consumes a lot of ammonia water, and the transportation volume is very large. The ammonia is easily distributed into the air, causing ammonia loss and polluting the air at the same time.

[0007] In summary, there are different problems in the above-mentioned various methods, such as complicated equipment, high production cost, and some problems such as secondary pollution, so the above-mentioned process method still needs to be further improved

Images