Circulating trapping method and system for mercury in flue gas

Abstract

The invention discloses a circulating trapping method and system for mercury in flue gas, relates to the field of flue gas mercury control, and aims to solve the problems of incomplete catalyst adsorption and secondary pollution in the prior art. According to the technical scheme, the circulating trapping method comprises the following steps that 1, mercury-containing flue gas passes through a circulating fluidized bed adsorption furnace filled with a metal oxide catalyst, and the mercury-containing flue gas passes through a circulating fluidized bed adsorption furnace filled with the metal oxide catalyst; the catalyst adsorbs mercury; carrying out gas-solid separation on the clean flue gas and the waste catalyst, and introducing the separated waste catalyst into a circulating fluidized bed regeneration furnace; then high-temperature regeneration gas is introduced, the adsorbed mercury oxide is decomposed, and mercury obtained through decomposition is recycled; the regenerated catalyst is sent back to the circulating fluidized bed adsorption furnace to realize the circulation of the catalyst; the circulating fluidized bed system is used for realizing circulating trapping of mercury in the flue gas, so that the contact time of the flue gas and catalyst particles is prolonged, and recovery and cyclic utilization of a catalyst and recovery of mercury resources are easy to realize; the mercury released by catalyst analysis can be recycled after being treated.

Description

technical field [0001] The invention relates to the field of flue gas mercury control, in particular to a method and system for circulating and capturing flue gas mercury. Background technique [0002] Mercury has serious harm to human body and ecological environment. There are three main forms of mercury in flue gas: elemental mercury (Hg 0 ), mercury oxide (Hg 2+ ) and particulate mercury (Hg p ). Hg p and Hg 2+ Can be efficiently removed by particle control devices and wet flue gas scrubbers, however, Hg 0 It is extremely volatile and insoluble in water, and it is difficult to directly remove it by the existing flue gas purification device. Therefore, Hg 0 It is the focus of flue gas mercury emission control. [0003] At present, catalyst injection technology is one of the main control technologies for mercury in flue gas. In injection technology, in order to ensure sufficient mercury removal efficiency, a large amount of catalyst needs to be injected. However, ...

AI Technical Summary

Problems solved by technology

In injection technology, in order to ensure sufficient mercury removal efficiency, a large amount of catalyst needs to be injected, however, the contact time with the flue gas is only a few seconds, and a large amount of catalyst is discharged from the flue far before reaching saturation, resulting in a large waste of materials , high cost of mercury removal

In addition, the powder catalyst after adsorbing mercury enters the combustion by-products such as fly ash and gypsum, which increases the mercury content in the residue, the potential risk of secondary release of mercury, and the difficulty of recycling mercury resources

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