Online monitoring system and method for concentration of sulfite ions in desulfurization slurry

Abstract

The invention relates to the technical field of online monitoring of the concentration of sulfite ions, in particular to an online monitoring system and method for the concentration of sulfite ions in desulfurization slurry. The system comprises a desulfurization slurry tower, a liquid storage device, a scale liquid collecting pipe and a control system, wherein a sulfite ion electrode is arranged in the liquid storage device, one side of the liquid storage device is communicated with a slurry tank of the desulfurization slurry tower, and the other side of the liquid storage device is communicated with the graduated liquid collecting pipe by arranging a liquid overflow port; scales are arranged on the tube wall of the graduated liquid collecting tube, a liquid level meter is further arranged in the graduated liquid collecting tube, and an electromagnetic pulse pump and a liquid injection pump are connected to the graduated liquid collecting tube; the data input end of the control system is respectively connected with the sulfite ion electrode and the liquid level meter, and the output control end of the control system is connected with the electromagnetic pulse pump and the liquid injection pump. The system is simple in structure, reasonable in design and high in measurement accuracy, and can provide real-time concentration of sulfite ions in a desulfurization slurry pond for a thermal power plant.

Description

technical field [0001] The invention relates to the technical field of on-line monitoring of sulfite ion concentration, in particular to an online monitoring system and method of sulfite ion concentration in desulfurization slurry. Background technique [0002] The limestone-gypsum wet desulfurization process has a series of advantages such as fast reaction speed, high desulfurization efficiency, mature process and reliable operation. This desulfurization process is currently the most widely used desulfurization method in thermal power plants. The core of the process is: the flue gas is absorbed by the limestone in the slurry of the absorption tower (the main component is CaCO 3 ) washing, SO in the washing process 2 The gas is removed, and calcium sulfite is obtained at the same time, and then oxidized by oxygen air, and then the by-product gypsum (CaSO 4 2H 2 O) Crystals. Its chemical reaction equation is as follows: [0003] CaCO 3 +H 2 O+2SO 2 →Ca(HSO 3 ) 2 +C...

AI Technical Summary

Problems solved by technology

The content of sulfite can reflect the degree of oxidation of the desulfurization slurry to a certain extent. At present, there is no system and method for online monitoring of the concentration of sulfite ions in the desulfurization slurry in the industry. The oxidation of the desulfurization slurry in the desulfurization tower depends entirely on experience , can not truly reflect the oxidation of the sulfuric acid slurry in the tower, resulting in frequent occurrence of under-oxidation

Occurrence of underoxidation can easily cause the following hazards: 1) Excessive sulfite content, serious scaling of the system and method, endangering the safe operation of the system and method; 2) Insufficient oxidation, resulting in the formation of thiosulfate, increasing the COD of the slurry, sub Sulfate is both oxidizing and reducing, and is a water pollutant that releases SO after decomposition 2 Return to the flue gas to reduce the desulfurization efficiency; 3) The sulfite in the gypsum slurry exceeds the standard, and qualified gypsum crystals cannot be formed. The particle size of the calcium sulfite is small, the dehydration of the gypsum is difficult, and the quality of the gypsum is reduced; 4) The high concentration of sulfurous acid Salt coats the limestone particles and prevents them from dissolving, causing limestone occlusion, resulting in a decrease in desulfurization efficiency

[0006] Therefore, it is very important to control the concentration of sulfite ions in the desulfurization slurry, but the current measurement equipment or methods have problems such as inaccurate measurement results and inability to reflect the oxidation situation in the reaction tower online in real time, etc.

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