Pulverized coal oxygen-rich combustion method and system

Abstract

The invention discloses a pulverized coal oxygen-rich combustion method. According to the method, based on traditional oxygen-rich combustion CO2 enrichment, oxygen proportions in a primary air and a secondary air are adjusted to ensure that the oxygen concentration of the primary air is higher than the oxygen concentration of the secondary air, wherein the oxygen content of the primary air is about 30-50 %, the oxygen content of the secondary air is 10-25 % and a third air is pure oxygen; oxygen volume flow entering a furnace chamber takes up 25-35 % of total furnace chamber air volume flow; the pulverized coal is carried by the primary air; the proportion of the primary air to the secondary air is (5 %-25 % ) to (95 % - 75 %); the oxygen excess air coefficient is 1.0-1.2. The invention further provides a corresponding pulverized coal oxygen-rich combustion system. According to the pulverized coal oxygen-rich combustion method, the stability of combustion is improved, the temperature distribution in combustion process is changed and the NOX generation is reduced eventually; after the improvement, the thermal utilization efficiency can be increased by 5-15% and generated NOX can be reduced by 15-45 %.

Description

technical field [0001] The invention belongs to the field of combustion of coal-fired boilers, and more specifically relates to a pulverized coal oxygen-enriched combustion method and system. The present invention can not only significantly reduce NO in the combustion process X generation, and improve the thermal efficiency of combustion. Background technique [0002] Oxygen-enriched combustion refers to the combustion of fuel in an oxygen-enriched atmosphere with a higher oxygen concentration than air. Use pure oxygen instead of air as the oxidant for combustion to obtain a high concentration of CO 2 , while recirculating part of the flue gas to control the flame temperature in the furnace and maintain proper heat transfer characteristics. High concentration of CO in flue gas 2 It is easy to capture, utilize and store, so as to achieve CO 2 purpose of emission reduction. However, due to the circulation of nitrogen-containing flue gas and the influence of air leakage i...

AI Technical Summary

Problems solved by technology

However, due to the circulation of nitrogen-containing flue gas and the influence of air leakage in the system, nitrogen elements in the flue gas continue to accumulate, resulting in NO in the flue gas X Increased emission concentration

And, CO 2 The specific heat capacity is different from that of nitrogen. Combustion in a larger specific heat capacity is prone to unstable combustion in the furnace, which affects the efficiency of the boiler.

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