Two-section flue gas alkali spraying and adsorption combined dechlorination system

Abstract

The invention discloses a two-section flue gas alkali spraying and adsorption combined dechlorination system. The system comprises an air pre-heater front flue, an air pre-heater, a dust remover front flue, a dust remover, a base solution dosing box and two atomizing nozzles; the air pre-heater front flue is communicated with an inlet of the dust remover through the air pre-heater and the dust remover front flue, the two atomizing nozzles are arranged in the air pre-heater front flue and the dust remover front flue respectively, and the system can achieve source reduction of desulfurization waste water and reduce the cost of a follow-up zero discharge system.

Description

technical field [0001] The invention belongs to the field of flue gas dechlorination and desulfurization wastewater treatment, and relates to a two-stage flue gas alkali spraying combined with adsorption dechlorination system. Background technique [0002] At this stage, the mainstream treatment technologies for zero discharge of desulfurization wastewater mainly include steam heat source evaporation crystallization, bypass flue gas evaporation zero discharge technology, etc. However, the current steam heat source evaporative crystallization and bypass flue gas evaporation zero-emission technologies all treat desulfurization wastewater from the end, which generally has the problems of high treatment cost and large investment. In fact, wet desulfurization technology is effective in reducing SO 2 While controlling, it also has a high removal efficiency for HCl. When the flue gas enters the desulfurization tower and contacts with the limestone slurry, the HCl in it is also cap...

AI Technical Summary

Problems solved by technology

However, the flue gas flow rate of coal-fired power plants is large (about 100000Nm under the condition of full load 300MW 3 / h) and the composition is complex, the concentration of HCl in the flue gas is very low, only a dozen to tens of ppm, and the dechlorination efficiency is affected by fly ash, SO 2 (hundreds to thousands of ppm), HF, SO 3 The influence of acidic gas such as acid gas is greater, and fly ash affects the contact area between alkali liquid and HCl, increases the resistance of acid gas to the liquid film, and increases the cost of direct contact between gas and liquid; SO 2 The concentration is tens or even hundreds of times that of HCl, which significantly competes with the reaction with the base solution. Other acid gases are roughly in the same order of magnitude as HCl, and there is also a competitive effect. Therefore, to achieve a higher dechlorination efficiency, it is necessary to increase Na / Cl ratio, which undoubtedly increases the processing cost

The current research on flue gas dechlorination mostly focuses on removing the atomized base solution by spraying it into the flue after the air preheater to react with HCl in the flue gas. If the amount of base solution sprayed is too low , and the dechlorination efficiency is also very low. If the amount of alkali solution is too large, there may be a risk of corrosion of the flue and subsequent dust removal treatment facilities due to incomplete atomization and evaporation, and it also increases the treatment cost.

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