Full-premixing denitration system of gas industrial boiler and control method

Abstract

The invention discloses a full-premixing denitration system of a gas industrial boiler. The full-premixing denitration system comprises a gas pressure regulating valve, an air pressure regulating valve, a premixing system and a combustion system. The premixing system comprises a gas flow divider, an air flow divider, a premixer and a mixing chamber. Gas and combustion air are subjected to three-stage flow dividing and one-time mixing correspondingly, the purpose of denitration through the premixing system and the combustion system is achieved, and the NOx emission standard is met. The invention further provides a control method based on the full-premixing denitration system of the gas industrial boiler. The whole system is automatically controlled through the gas pressure regulating valveand the air pressure regulating valve, and the system operation stability and work efficiency are improved.

Description

【Technical field】 [0001] The invention relates to the environmental protection technology of a gas industrial boiler, in particular to a fully premixed denitrification system and a control method for a gas industrial boiler. 【Background technique】 [0002] In recent years, the elimination of coal-fired boilers in various places has continued to increase, and the "coal-to-gas" or "oil-to-gas" efforts have continued to intensify. Nitrogen oxides (hereinafter referred to as NOx) emissions are limited to less than 200mg·Nm-3, which is only the most basic guidance on a national scale; after that, local standards have been continuously issued in various places, such as Beijing promulgated "Beijing local standard DB11 / 139-2015", the NOx emission limit is stricter, and the emission value is stipulated to be below 30mg·Nm-3. However, the emissions of existing small industrial boilers, especially coal-fired boilers, can only barely meet the requirements of the national standard GB13...

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Problems solved by technology

Some domestic scholars divide the premixed combustion technology into two categories: lean fuel premixed combustion and water-cooled premixed combustion; for lean fuel premixed combustion, if the excess air coefficient is too large, it is easy to defire on the combustion surface; If it is too small, it will easily cause the metal surface temperature to be too high. Both working conditions will cause the increase of NOx emissions. Therefore, controlling the excess air coefficient is the key to this combustion method; the structure of the water-cooled premixing system is complex, and boiler components need to be modified Too much, so these two premixing methods are inconvenient to use. Therefore, the problems for reducing NOx are: 1. The inhomogeneous mixing of fuel and combustion air in the early stage of premixed combustion will increase the NOx emissions, which will not Comply with the regulations; 2. The structure of the burner is too complicated and inconvenient to use

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