Desulfurization liquid cooperated chlorine dioxide gas-phase oxidation denitration integrated flue gas purification device and process

Abstract

The invention provides a desulfurization liquid cooperated chlorine dioxide gas-phase oxidation denitration integrated flue gas purification device and process, a desulfurization tower, an oxidation denitration tower and a secondary purification tower are communicated through a flue, and the flue gas flow direction is in an S-shaped layout. The flue gas subjected to dust removal firstly enters a desulfurizing tower and is desulfurized in an alkali liquor spraying and absorbing manner; the desulfurized flue gas is firstly mixed with ClO2 gas in an oxidation denitration tower to oxidize NO intoNO2, and then denitration is carried out in an alkali liquor spraying absorption mode; and the desulfurized and denitrified flue gas are sprayed and cleaned in the secondary purification tower again by using a desulfurizing solution, residual NOx and SO2 are absorbed in the flue gas, and demisting is performed by using wet electric precipitation to finish final purification. According to the invention, desulfurization, oxidation denitration, secondary purification and waste liquid pretreatment links which are independently arranged and organically combined are utilized to realize effective utilization of desulfurization liquid, ultra-clean treatment of flue gas, recovery of desulfurization and denitration products and reuse of process water, so that the effects of water saving and emissionreduction are achieved while the flue gas is purified.

Description

technical field [0001] The invention relates to the field of desulfurization and denitrification of boiler flue gas, in particular to an integrated flue gas purification device and process of desulfurization liquid in cooperation with chlorine dioxide gas-phase oxidation denitrification. Background technique [0002] SO in boiler flue gas 2 and NO x It is an important precursor substance to form air pollution phenomena such as acid rain or smog. Desulfurization and denitrification treatment of boiler flue gas is the key to control SO 2 , NO x Emissions and an important means to ensure the quality of the atmospheric environment. SO 2 It is easily soluble in water. At present, the lye wet desulfurization technology has been widely used due to its simple process, high efficiency and mature technology. while NO x Due to the insoluble NO in water, the denitrification method is relatively more complicated. Although the commonly used selective catalytic reduction (SCR) denit...

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Problems solved by technology

Although the device is highly integrated, the process is simple, and the floor space is small, there are problems: (1) The desulfurization and oxidation areas are in the same room, and the SO in the flue gas 2 Easy to flow to the oxidation zone, competing with NO to consume ClO 2 Oxidants will not only increase the oxidation cost, but also cause incomplete oxidation of NO, resulting in a decrease in denitrification rate; (2) sharing desulfurization and denitrification spray fluid will make the absorption of 2 The denitration spray liquid oxidizes SO in the desulfurization liquid 2 2- , causing the desulfurization liquid to lose its denitration effect, thereby increasing the amount of alkali used for denitration; (3) There is a partition between the oxidation zone and the denitration zone to increase the system resistance; (4) The design of a single tower should ensure that each section has sufficient reaction residence time , will inevitably increase the tower height or tower diameter, which will lead to an increase in construction and operation and maintenance costs; in addition, too large a tower diameter will easily cause a short circuit of the flue gas and affect the treatment effect

The purpose of this patent is to solve the problems of nitrite wastewater treatment and sulfur and nitrogen resource recovery in the simultaneous desulfurization and denitrification process, but the process requires NO 2 - and SO 3 2- The reaction pH, S / N ratio and temperature are relatively harsh, the hydrolysis temperature and pH requirements are also very strict, the operation process is complicated, and the cost of recycling resources is high. Therefore, this process is suitable for chemical production, but not suitable for the field of flue gas treatment. use

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