Flue gas desulfurization method and system

Abstract

The invention discloses a flue gas desulfurization method and system. The flue gas desulfurization method comprises the steps of countercurrently contacting flue gas containing SO2 with a lean liquid of an absorbing liquid in an absorption tower to form a rich liquid; The desorption regeneration is completed by the countercurrent contact of the secondary steam, and the part of the SO2-containing steam discharged from the top of the tower is injected by the fresh primary steam to form a regenerated primary steam, which is used as the heat source of the reboiler to heat the lean liquid in the desorption tower, producing two. Secondary steam continues to be used to strip SO2. The flue gas desulfurization system includes an absorption tower, a rich liquid preheater, a lean and rich liquid heat exchanger and a desorption tower which are connected in sequence. The desorption tower is respectively connected with the steam coupling regeneration device and the condenser, and the steam coupling regeneration device is connected with the reboiler. The reboiler is connected to the desorption column. The flue gas desulfurization method and system of the invention have the advantages of increasing the inlet temperature of the desorption tower of the rich liquid absorbing liquid, realizing the balance of circulating steam, saving steam consumption and reducing the heat load of the condenser.

Description

technical field [0001] The invention belongs to the technical field of flue gas desulfurization, and in particular relates to a flue gas desulfurization method and system which require steam to participate in the cycle regeneration of absorption liquid. Background technique [0002] With the development of industry, the emission of sulfur dioxide is increasing year by year, and the massive emission of sulfur dioxide has seriously damaged the ecological environment of our country. According to data, my country's annual sulfur dioxide emissions have exceeded 30 million tons, making it one of the countries with the most serious sulfur dioxide pollution in the world. Therefore, it is imminent to control sulfur dioxide flue gas pollution. [0003] There are many kinds of flue gas desulfurization technologies. Since the 1950s, many countries in the world have begun to study desulfurization technologies. Up to now, there have been hundreds of desulfurization technologies. Traditio...

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Problems solved by technology

However, this method has the following two problems: (1) The compressor is used to compress the regeneration gas to do work. When the obtained high-temperature and high-pressure superheated steam heats the bottom liquid of the regeneration tower, the amount of secondary steam generated is less than that of the primary steam entering the reboiler The amount of steam cannot solve the mass balance problem of circulating steam; (2) The vapor compression system (MVR evaporator) relies on electric energy / mechanical energy to compress the regeneration gas, the equipment structure is complex, expensive, and requires high maintenance. In addition, the steam at the top of the tower is corroded Strong resistance, and contains a large amount of sulfur dioxide non-condensable gas, which is not conducive to the stable operation of equipment

[0007] The Chinese patent document with the publication number CN102049176A discloses a high-gravity solvent circulation absorption flue gas desulfurization technology, which uses nitrogen, air, etc. as the regenerative stripping gas. This method can save energy to a certain extent, but there are Problems such as incomplete liquid desorption and difficult recovery of sulfur resources

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