Particle input amount calculation method based on selenium removal model, and application thereof

Abstract

The invention belongs to the field of pollutant removal, and particularly discloses a particle input amount calculation method based on a selenium removal model, and application thereof. The method comprises the following steps: calculating the droplet speeds at different positions in a desulfurization tower, the relative speed of droplets and flue gas, the flue gas temperature, the droplet temperature, the trapping efficiency of droplet groups on particles and the number concentration of the particles; calculating the concentration of gaseous selenium entering the droplets at the ith positionin the desulfurization tower, obtaining the concentration of gaseous selenium in the flue gas at the ith position in the desulfurization tower, substituting the concentration into the steps for iterative calculation, repeating the process until the concentration of gaseous selenium at the outlet of the desulfurization tower is obtained, obtaining the concentration of granular selenium at the outlet of the desulfurization tower at the same time, calculating the selenium removal efficiency in the desulfurization tower by utilizing the calculation result, and further obtaining the particle inputrate in the selenium removal process of the desulfurization tower according to the calculation result. According to the invention, the quantity of the input particles can be ensured, so that gaseousselenium pollutants in the flue gas are fully condensed and are completely captured in the desulfurzation tower, and secondary pollution caused by escape of the particles is avoided.

Description

technical field [0001] The invention belongs to the field of pollutant removal, and more specifically relates to a method for calculating the input amount of particulate matter based on a selenium removal model and its application. Background technique [0002] Selenium is a trace heavy metal element. Excessive selenium discharge will cause serious threats to human health and ecosystems. my country is a large coal-fired power generation country, and coal-fired power plants are one of the main anthropogenic sources of selenium in the environment. According to the survey, the average content of selenium in raw coal in my country is higher than the world average level. Therefore, the emission of selenium pollutants caused by coal burning in my country is extremely serious and must be strictly controlled. [0003] In the high temperature environment of coal-fired boilers, most of the selenium combined with minerals in raw coal will be gaseous selenium dioxide (SeO 2 ) in the f...

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Problems solved by technology

This may be related to various complex factors such as upstream flue gas components, upstream pollutant control equipment, wet flue gas device layout and operating status, resulting in extremely unstable control effect of wet flue gas desulfurization devices on selenium pollutants. The wet flue gas desulfurization device is usually the last link in the flue gas purification process, which also causes a large amount of unremoved selenium pollutants to be discharged from the chimney and enter the atmospheric environment, which will undoubtedly affect the lives and ecology of residents around coal-fired power stations. environment, as well as the global atmospheric environment, pose a serious threat that must be controlled and addressed

[0004] Existing control technologies for the emission of selenium pollutants in coal-fired flue gas mainly include: (1) Li Yuzhong proposed a medium temperature range (700 -740℃) using calcium oxide to remove SeO by chemisorption 2 The method has the advantages of water saving, energy saving, and reliable operation. However, at present, most coal-fired units in my country use wet flue gas desulfurization technology (over 90%), and this deselenization method is applied to medium temperature circulating fluidized bed desulfurization technology. , not applicable to the current situation of my country's coal-burning pollutant control; (2) CN109045963A discloses a method for oxidation-absorption removal of gaseous selenium dioxide in coal-fired flue gas. It is sprayed into the upper part of the spray tower, and forms a convection flow with the coal-fired flue gas introduced from the lower part of the spray absorption tower, so that the gaseous SeO in the flue gas 2 Fully reacted to realize SeO 2 Conversion to selenate and absorption

The highest oxidation efficiency of this method can reach 99%, and the absorption efficiency can reach more than 98%. Consumes a large amount of chemical reagents, high operating costs, and will change the properties of the slurry, which may affect the operating life and stability of related pipeline equipment; (3) CN110882619A discloses a base adsorbent for capturing selenium in coal-fired flue gas The method uses calcium hydroxide powder and polymer sodium alginate powder as raw materials to prepare sodium alginate α-L-guluronic acid units with cross-linked structure, and captures and intercepts granular selenium to form flocculation body, but this method needs to pass the flue gas into the base adsorbent solution, which cannot be coupled with the current mainstream coal-fired flue gas purification process, and its application is limited

The existing selenium pollutant emission control technology in coal-fired flue gas mainly has the following problems: (1) it is not suitable for the existing mainstream coal-fired flue gas purification process in my country, and its application is limited; (2) it needs to consume a large amount of chemical reagents , the operating cost is high, and may affect the stability of the system

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