System for super clean removal of sulfur dioxide in coal-fired flue gas and process of system

Abstract

The invention relates to the technical field of coal-fired flue gas desulfurization, and particularly provides a system for super clean removal of sulfur dioxide in coal-fired flue gas. The system comprises a desulfurization tower, a flue gas inlet is arranged in the middle lower part of the desulfurization tower, a flue gas outlet is arranged in the top end of the desulfurization tower, a main desulfurization zone, a deep desulfurization zone, and a high-efficiency demister are arranged between the flue gas inlet and the flue gas outlet from the bottom to the top, a low-pH slurry oxidation tank is arranged at the bottom end of the desulfurization tower, and a reaction tank system is arranged outside the desulfurization tower. The invention also provides a process of the system for the super clean removal of the sulfur dioxide in the coal-fired flue gas. The process comprises the following steps: the raw flue gas firstly passes through the main desulfurization zone to remove most of the sulfur dioxide in the flue gas, deep desulfurization is performed in the deep desulfurization zone, and finally after fine mist droplets carried by the flue gas are removed by the high-efficiency demister, the purified flue gas is discharged out from the desulfurization tower through the flue gas outlet. The system and process provided by the invention have a good deep desulfurization function and can strictly meet super clean emission standards of the coal-fired flue gas, and the whole desulfurization system is safe to operate and convenient to maintain.

Description

technical field [0001] The invention relates to the technical field of desulfurization of coal-fired flue gas, in particular to a system and process for ultra-clean removal of sulfur dioxide in coal-fired flue gas. Background technique [0002] In recent years, many cities in my country have experienced relatively serious air pollution, which has caused serious harm to the life and health of urban residents. Pollutants contained in coal-burning flue gas are an important source of air pollution. Sulfur dioxide and nitrogen oxides in coal-burning flue gas are the main cause of acid rain and play an important role in the formation of smog. Therefore, the Chinese government is gradually implementing more stringent emission standards for coal-fired flue gas. In the power field, coal-fired flue gas pollutants must meet ultra-clean emission standards (the ultra-clean emission standard limit for sulfur dioxide in coal-fired boilers in the electric power field is 30mg / Nm3), and gra...

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Problems solved by technology

[0004] With the implementation of stricter emission standards for coal-fired flue gas pollutants, the conventional limestone-gypsum desulfurization process is difficult to meet the requirements of ultra-clean emission standards

Although the dual-alkali desulfurization process has the advantage of a high pH value of the desulfurizer solution, the oxidation rate of sulfite in a high pH value environment is extremely low, resulting in serious scaling inside the desulfurization tower and pipeline, making the desulfurization device unsafe ,Stable operation

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