Ammonia spraying device for flue gas denitrification

Abstract

The invention relates to an ammonia spraying device for flue gas denitrification, and belongs to the technical field of flue gas denitrification systems. The ammonia spraying device comprises a group of main pipes, and is characterized in that the main pipes are arranged in a layered way in the flue gas direction; the main pipes in each arrangement layer are arranged in parallel at equal intervals and respectively vertical to the flue gas direction; a group of branch pipes are correspondingly arranged on two sides of each main pipe, wherein the branch pipes are vertically connected with the main pipes and arrayed in parallel, and the branch pipes in the same vertical plane, which are parallel to the flue gas direction, form a step-type structure; and conical spray holes are symmetrically arranged in the front and back corresponding branch pipes, which take the main pipes connected with the branch pipes as centers. The ammonia spraying device can be widely applied to various flue gas denitrification systems, can timely adjust the spraying flow rate of a reducing agent according to flue gas flow information fed back in real time, dynamically maintains the optimal matching and mixing effect between the reducing agent and flue gas fluid in different spraying areas, has the characteristics of easiness in adjustment, strong load adaptability, uniform ammonia spraying, good mixing effect, simple structure, convenience for installation and maintenance, low construction and operation cost and the like, and guarantees the efficient and stable operation of the flue gas denitrification system.

Description

technical field [0001] The invention belongs to the technical field of flue gas denitrification systems, and in particular relates to a flue gas denitrification ammonia injection device suitable for a flue gas selective catalytic reduction denitrification process. Background technique [0002] At present, the most widely used flue gas denitrification technology in domestic and foreign power plants is the Selective Catalytic Reduction process (SCR). The nitrogen oxides in the flue gas are fully mixed and reacted to generate nitrogen and water to achieve the purpose of denitrification. The reducing agent used in this process needs to be evenly sprayed into the flue through the corresponding ammonia injection device to mix with the flue gas. The uniform mixing degree of the reducing agent and the flue gas will directly affect the operating efficiency and effect of the denitrification system. When the mixing effect When it is not good, there will be adverse effects such as low ...

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Problems solved by technology

The reducing agent used in this process needs to be evenly sprayed into the flue through the corresponding ammonia injection device to mix with the flue gas. The uniform mixing degree of the reducing agent and the flue gas will directly affect the operating efficiency and effect of the denitrification system. When the mixing effect When it is not good, there will be adverse effects such as low denitrification efficiency, high ammonia escape rate, and increased operating resistance of the air preheater. In severe cases, it will also affect the safe and stable operation of the boiler main engine

[0003] Ammonia injection devices commonly used in the prior art are basically nozzle-type, and are generally arranged in the same plane, but many shortcomings are found in practical applications: first, the effect of ammonia injection mainly depends on the number of nozzles per unit area, when When the denitrification efficiency is required to be high, a large number of nozzles need to be configured, the structure is complex, the manufacturing and maintenance costs are high, and it is uneconomical; secondly, when the number of nozzles is limited, to meet the high mixing requirements, it is often necessary to spray A forced mixing device is installed after the ammonia device. This structure will increase the length of the straight section of the flue, which is restricted by the site conditions; Frequently, the traditional nozzle-type ammonia injection device is not effective in spraying ammonia under low load conditions. Therefore, due to the lack of adjustability of the device, the applicability to variable load conditions is not strong

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