Wet process calcium-based smoke gas desulfurization system and application thereof

Abstract

The invention relates to a wet process calcium-based smoke gas desulfurization system and application thereof. The system comprises a main smoke gas pipeline, a pressurizing fan, a desulfurization tower, a clarifier, a waste water groove, a concentration crystallization tower and a waste salt filter, wherein the pressurizing fan is arranged on the main smoke gas pipeline; the desulfurization tower communicates with the pressurizing fan; the clarifier, the waste water groove, the concentration crystallization tower and the waste salt filter are sequentially arranged at the downstream of the desulfurization tower; the concentration crystallization tower communicates with the main smoke gas pipeline and the waste water groove through a smoke gas conveying pipeline and a waste water conveying pipeline. Compared with the prior art, the wet process calcium-based smoke gas desulfurization system has the advantages that the clean smoke after desulfurization can be discharged in a standard reaching way; partial original smoke gas performs heat exchange with the desulfurization waste water, so that the desulfurization waste water is evaporated and concentrated; further, the zero discharge of the waste water is realized; the process energy consumption is obviously reduced; the operation cost is low; the high-quality solid gypsum product and a small amount of salt slag capable of being easily handled through being buried can be obtained; the environment-friendly effect is achieved; the process is simple; good application prospects are realized.

Description

technical field [0001] The invention belongs to the technical fields of chemical industry and environmental protection, and relates to a wet calcium-based flue gas desulfurization system and its application. Background technique [0002] Thermal power is the main power source in my country, and thermal power generation is basically based on coal-fired power generation. The massive consumption of coal has brought enormous pressure to the environment, and the SO contained in its flue gas 2 , not only can directly cause harm to the ecological environment, but also is an important precursor for the formation of acid rain and haze. Power plant flue gas desulfurization technology is to control SO 2 important measure of pollution. [0003] Among many flue gas desulfurization methods, limestone-gypsum wet flue gas desulfurization is currently the most mature and widely used desulfurization technology in the world. Its chemical principle includes gas phase SO 2 Absorption and dis...

AI Technical Summary

Problems solved by technology

However, this process also has some disadvantages, such as high initial investment and operating costs, large water consumption, large consumption of absorbent raw materials, large floor area, and easy scaling, blockage, corrosion and wear of equipment.

In addition, an important problem faced by this technology is the treatment of desulfurization wastewater

[0004] Patent CN105032149A discloses a calcium carbonate / calcium hydroxide-gypsum wet flue gas desulfurization and dust removal technology, which uses water as a desulfurizer to contact the raw smoke to complete the desulfurization and dust removal, and the purified flue gas exchanges heat with the raw smoke and is discharged from the chimney; The acid-containing aqueous solution after desulfurization is neutralized with calcium carbonate or calcium hydroxide slurry, and then gypsum is obtained after oxidation and dehydration. The disadvantage of this method is that in order to obtain high-quality gypsum that meets the requirements of building materials, a large amount of salt and heavy metal must be discharged. High wastewater, which will cause new secondary pollution

[0005] Patent CN100560186C discloses a dilute solution magnesium-calcium double-alkali flue gas desulfurization process, using MgSO 3 As the main desulfurizer, it is regenerated with lime milk slurry. This method can avoid the hard scale of magnesium sulfate produced in the lime-gypsum method, but it is limited by the insufficient source of MgO and the high content of magnesium ions in the process wastewater. come difficult

[0006] Chinese patent 201610421022.4 discloses a new flue gas desulfurization and denitrification process, which uses a fluidized bed reactor with a catalyst and calcium-based absorbent to remove sulfur and nitrate in the flue gas, and then removes sulfur and nitrate in the fluidized bed reactor. The flue gas of nitrate is separated from gas to solid, and part of the separated solid matter is returned to the fluidized bed reactor for reuse. Although this method has high desulfurization and destocking efficiency, the fluidization process is relatively complicated and it is difficult to operate stably

At present, the zero-emission technology adopted in China is mainly based on the multi-effect evaporation and concentration process of desulfurization wastewater, which consumes a lot of energy and has high operating costs.

Patent CN101417827B discloses a process for treating desulfurization wastewater. The basic idea is that the atomized water and flue gas directly contact and exchange heat in the drying tower, and the formed particles settle to the lower part of the drying tower, and the flue gas after heat exchange becomes Wet flue gas is discharged from the drying tower. This process has problems such as poor particle settling effect, low dust removal efficiency, and high equipment investment costs.

Images