Experimental study of key parameters of natural gas-activated pulverised coal reburning

Abstract

In the study of coal powder reburning technology, combining the coal powder delivery via recirculating flue gas and natural gas conditioning was proposed. The purpose of this approach is to enhance the reduction capability of coal powder reburning, thereby reducing the emission of nitrogen oxides from coal-fired boilers. The main objective of the research is to explore how to utilize the highly reactive components in natural gas to create a more favorable environment for coal powder to reduce nitrogen oxides. To achieve this, a detailed investigation of the entire process of natural gas conditioning was conducted using a multi-reaction control section with a flow reactor experimental system simulating actual coal-fired boiler conditions. The results revealed that the abundant reduction substances generated during natural gas conditioning, such as CO*, OH*, H, and CHi, optimized the physical and chemical structure of coal char, thereby enhancing its ability to reduce nitrogen oxides. Compared with traditional coal powder delivery via recirculating flue gas, the addition of natural gas conditioning significantly increased the efficiency of nitrogen oxide reduction by approximately 12.23%. Through experimental investigation and data analysis, the significant impact of natural gas conditioning technology on coal powder reburning was elucidated, and the specific parameter requirements for engineering applications were proposed. From an engineering perspective, the precise control of the excess air ratio, residence time, and fuel ratio in the reburning zone is essential to achieve a high-efficiency nitrogen oxide reduction while ensuring a complete coal powder combustion and economic feasibility. Overall, adopting natural gas conditioning technology can not only guarantee ultra-low nitrogen oxide emissions but also minimize the use of reactive gases, thereby enhancing the economic efficiency of system operation. This flexible use of natural gas technology has demonstrated some promising results in laboratory conditions and offers feasible solutions for engineering practice, ensuring the economic efficiency of system operation.

Keywords

• natural gas
• modification
• reburning
• nitrogen oxides
• combustion parameters