An economizer for improving denitrification capability of scr system in low load operation

Abstract

The invention relates to a coal economizer improving the low-load running denitration capability of an SCR system. The coal economizer comprises an air guide grate and a heat conduction device. The air guide grate is formed by sequentially arranging multiple grate layers, an installation hole is formed in the air guide grate, and a hot water pipe penetrates the installation hole to be connected with the air guide grate in a matched manner. The heat conduction device comprises a heat absorption pipe, a heat dissipation pipe and a supercharging mechanism. The two ends of the heat absorption pipeare connected with the two ends of the heat dissipation pipe, and the supercharging mechanism is arranged at the connecting position of the heat absorption pipe and the heat dissipation pipe. Heat conduction media are arranged in the heat absorption pipe and the heat dissipation pipe, the heat absorption pipe is installed between the grate layers, and the heat dissipation pipe is installed at theflue gas inlet position of the SCR reactor. Compared with the prior art, by means of the coal economizer improving the low-load running denitration capability of the SCR system, heat of the coal economizer can be transmitted to the SCR reactor, the denitration capability of the SCR system is better improved, and the coal economizer has the beneficial effects of being simple in structure, convenient to install, good in heat exchange effect, wide in application range and the like.

Description

technical field [0001] The invention relates to an economizer, in particular to an economizer which improves the denitrification capability of an SCR system in low-load operation. Background technique [0002] The economizer is a device installed in the lower part of the flue at the tail of the boiler to recover the waste heat of the exhausted smoke. It heats the boiler feed water into the heating surface of saturated water under the pressure of the steam drum. The exhaust temperature of the flue gas is reduced, energy is saved, and efficiency is improved, so it is called an economizer. [0003] SCR is the most mature flue gas denitration technology at present. It is a post-furnace denitration method. It was first commercialized in Japan in the late 1960s and 1970s. It uses reducing agents (NH3, urea) under the action of metal catalysts. Selectively reacts with NOx to form N 2 and H 2 O, instead of being O 2 Oxidation is called "selectivity". The popular SCR processes i...

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Problems solved by technology

[0005] At present, the method of increasing the flue gas temperature at the inlet of the SCR reactor is to use high-temperature flue gas heating, that is, the high-temperature flue gas is drawn from the front of the boiler economizer or the low-temperature superheater, and the flue gas at the inlet of the SCR reactor passes through the bypass flue, the regulating baffle, and the flue gas. Gas mixing to adjust the flue gas temperature at the inlet of the reactor, but this method requires the system to have high rigor and flexibility. If the deformation causes a large amount of high-temperature flue gas to leak when the closure is not tight, it will affect the efficiency of the boiler. The air flow disturbance will also cause uneven temperature distribution after mixing; at present, the technical means of segmental arrangement of economizers is also used to increase the flue gas temperature, and a part of the economizer area is patented in the flue behind the SCR reactor, but the method's The transformation workload is heavy and the investment cost is high

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