Flue distribution manner applied to negative omnidistance load commissioning of denitration equipment

Abstract

The invention discloses a flue distribution manner applied to negative omnidistance load commissioning of denitration equipment. According to the flue distribution manner, a main flue is arranged, other heating surfaces, an economizer, SCR (semiconductor control rectifier) equipment and an air preheater are arranged on the main flue, and all or a part of the main flue is in a U shape or an inverse U shape; fume passes through the other heating surfaces of a boiler body after burning in a power boiler, the fume firstly passes through the economizer, enters the SCR equipment through the main flue connected with the SCR equipment, and finally enters the air preheater through an inlet flue of the air preheater; a bypass flue communicated with the SCR equipment is arranged at an inlet of the economizer of a tail flue of the boiler or the other high temperature regions, and the SCR equipment is provided with a regulating device used for controlling the fume which can enter the bypass flue; and the bypass flue is shorter than the corresponding main flue. The flue distribution manner provided by the invention ensures that the fume temperature of the SCR equipment which is higher than the reaction temperature required by a catalyst under all loads.

Description

technical field [0001] The invention relates to the field of boiler equipment, in particular to the arrangement of boiler flues. Background technique [0002] As the country pays more and more attention to environmental protection, in order to ensure the final NOx emission target, denitrification equipment has become one of the standard configurations of boilers in the future while using low NOx combustion equipment. In the conventional boiler design, if SCR (Selective Catalytic Reduction) denitrification method is adopted, the denitrification device is usually arranged at the outlet of the boiler heating surface and the inlet of the air preheater. However, in order to ensure that the boiler can achieve higher efficiency at the same time, the flue gas temperature of the air preheater is usually around 350~400°C at full load, and the flue gas temperature can meet the operation requirements of SCR equipment under high load. However, as the load decreases, the temperature of t...

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Problems solved by technology

However, as the load decreases, the temperature of the flue gas passing through the SCR equipment also decreases. If it is lower than a certain temperature (such as 315°C, see the SCR equipment for specific requirements), the catalyst in the SCR equipment cannot work, so it cannot play a role. The role of deNOx

If it is ensured that the temperature of the flue gas entering the SCR device meets the reaction temperature of the catalyst at full load, the temperature of the flue gas entering the SCR device at full load is much higher than the conventional value. Also, because the flue gas passes through the SCR device, there is basically no significant temperature drop. Such a high flue gas temperature entering the air preheater can not use the material of the original air preheater, and the second is that only through the air preheater can not meet the requirements of the conventional exhaust gas temperature, resulting in an increase in the exhaust gas loss of the boiler

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