Circulating fluid bed flue gas desulfurization technique and device

Abstract

The invention discloses a circulating fluidized bed flue gas desulfurization process which takes a calcium-based desulfurizing agent as a bed material and a device thereof. The process and the device are characterized in that a lime preparation and supply system comprises a main powder silo and a digester; a flue gas inlet structure, a circulating fluidized bed desulfurization reaction tower, a primary dust collector, a secondary dust collector are connected from beginning to end; the lime preparation and supply system is connected with a venturi fluidization throat pipe arranged at the lower part of the circulating fluidized bed desulfurization reaction tower; the upstream of a feed back distributing tank is connected with an ash hopper of the primary dust collector, and the downstream thereof is connected with a discharge pipe and a circulating ash humidification activator, and the humidified and activated circulating ash enters a venturi pipe outlet arranged at the lower part of the circulating fluidized bed desulfurization reaction tower. The flue gas enters from the bottom of the desulfurization reaction tower, contacts and reacts with a desulfurizing agent and the circulating ash in the tower, desulfurization by-products enter the dust collector together with the flue gas, most of the circulating ash separated by the dust collector is delivered to the tower by the humidification activator. The circulating fluidized bed flue gas desulfurization process and the device thereof have the advantages that when the amount of the water in the tower is the same, desulfurization efficiency can be greatly improved; when the desulfurization reaction tower is not injected with water or injected with little water, the problems of sticking wall and scale formation can be effectively avoided.

Description

Technical field: [0001] The invention belongs to the field of industrial waste gas purification and environmental protection and chemical industry, and particularly relates to a circulating fluidized bed flue gas desulfurization process and device using calcium-based desulfurizer as bed material. Background technique: [0002] Existing circulating fluidized bed semi-dry flue gas desulfurization methods mostly use digested lime (slurry) as an absorbent, and remove flue gas through a strong three-phase action of gas, liquid and solid in the fluidized bed reaction tower. Sulfur dioxide and other harmful substances in the gas. The traditional method is shotcrete technology. The disadvantage is that the lime slurry system used is not only complicated in the process system and equipment, but also covers a large area, and the mortar conveying pipeline is prone to scale and blockage, which reduces the availability of the system and increases the system. Operating maintenance and repair c...

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Problems solved by technology

However, in thermal power plant boiler flue gas desulfurization technical transformation projects, there are often restrictions and requirements such as narrow usable space, unsuitable long shutdown and reconstruction time, and dust emission compliance. The above two patented technologies have great obstacles in application. The reasons are: (1) Lime digestion must be arranged nearby, which may be limited by space; (2) The elevation of the ash hopper of the electrostatic precipitator (bag filter) is usually low, and it is difficult to directly return it to the tower with an air chute or a screw conveyor. Inside, if the transformation is carried out, the project volume will be large and the shutdown time will be long; (3) The electrostatic precipitator (bag filter) is used as the external separation device, so the dust concentration at the inlet of the electrostatic precipitator (bag filter) is large , it is difficult to achieve dust emission standards

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