Boiler system capable of combining oxygen-enriched air and air combustion

Abstract

The invention discloses a boiler system capable of combining oxygen-enriched air and air combustion. The system can combine combustion of two work conditions of oxygen-enriched air and air. Tail double flues are designed on the boiler system. Economizers and preheaters are alternately arranged, circulation primary air and circulation secondary air are independently preheated, and the different requirements for the temperature and pressure of the circulation primary air and the circulation secondary air and the hot air temperature under different combustion work conditions are met. Meanwhile, a GGH system is designed at the tail portion, the inflow combustion supporting gas temperature is increased, and heat exchange in the preheaters is reduced so as to increase the exhausting temperature and reduce the low-temperature corrosion. The circulation primary air oxygen injection position and the circulation secondary air oxygen injection position are independently designed, oxygen injection is conducted on the primary air behind preheater units, oxygen injection is conducted on the secondary air before the preheater units, and therefore the hot air temperature is increased; and the hot air temperature under the oxygen-enriched air work condition is closer to the hot air temperature under the air work condition, and finally, smooth switching running of combining of two combustion work conditions of oxygen-enriched air and air is achieved.

Description

technical field [0001] The invention belongs to the technical field of boilers, and more specifically relates to a boiler system compatible with oxygen enrichment and air combustion. Background technique [0002] Oxyfuel combustion technology is considered to have the most potential for large-scale CO 2 One of the captured techniques. This technology is suitable for new construction or renovation of existing air boilers because of its good compatibility with traditional air-fired boilers in terms of technology and process. Under the oxygen-enriched combustion mode, due to the significant change of the combustion atmosphere, the combustion characteristics of pulverized coal, flame characteristics, flue gas components, radiation, and convective heat transfer all undergo significant changes, which in turn leads to changes in the heat absorption of the boiler heating surface. Due to the lack of design standards and specifications for the new oxy-fuel combustion boiler system, ...

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Problems solved by technology

[0004] (1) The temperature requirements of the primary and secondary air and hot air are different, and the pressure difference between the primary and secondary air is also large. It is very difficult to switch between oxygen-enriched combustion and air combustion in the actual operation of the system

[0005] (2) In oxygen-enriched combustion, the heat transfer capacity of the heating surface is enhanced to varying degrees, and the heat capacity of the flue gas increases, and the exhaust gas temperature is often lower than the exhaust gas temperature of air combustion, and low-temperature corrosion is very likely to occur

Due to the design of common boiler systems, one-time injection before the preheater is often selected, so that too much supporting gas will increase the heat release of the flue gas and the exhaust gas temperature is too low

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