Experimental study on bituminous coal blending in a down‐fired boiler with anthracite combustion system under low load

Abstract

The industrial experiments were carried out to study the bituminous coal blending in a 660‐MWe supercritical down‐fired boiler with anthracite combustion system under low load. The influence of the bituminous coal ratio on the boiler thermal efficiency, flue gas temperature, flue gas species, and heat transfer of various heating surfaces was analyzed in detail. The ignition distances of three experimental coals were measured, and the influence mechanism of bituminous coal blending on the combustion, heat transfer, and NOx emission in the furnace was proposed. The results show that increasing the bituminous coal blending ratio is beneficial to reduce NOx emissions. However, it leads to the rise of the exhaust gas temperature and the decrease of the boiler efficiency, which can be ascribed to the large amount of the cold primary air sent into the pulverizing system to control the air pulverized coal flow temperature at the mill outlet. The ignition distances of three experimental coals are different. The ignition distance from short to long follows the following order, that is, bituminous coal, lean coal, and anthracite. The earlier ignition of the bituminous coal leads to a sharp rise in the temperature of the airflow at the burner nozzle outlet, a rapid expansion of the airflow volume, and a sharp attenuation of the airflow rigidity, resulting in a short flame downward penetration depth and the upward movement of the flame center in the furnace. As the bituminous coal is blended, the change of the flame center and the flame fullness in the furnace affects the flue gas temperature distribution. Similarly, the change of the radiant heat transfer intensity and the convective heat transfer intensity affects the heat absorption distribution of the heating surface in the furnace.

Optimisation of Solid Fuel In-furnace Blending for an Opposed-firing Utility Boiler: A Numerical Analysis

“…Electricity and heat production are largely responsible for rising carbon dioxide (CO 2 ) emissions [1]. As the world population has grown, so has the demand for electrical generation, necessitating the use of coal, natural gas, and oil [1].…”

“…Electricity and heat production are largely responsible for rising carbon dioxide (CO 2 ) emissions [1]. As the world population has grown, so has the demand for electrical generation, necessitating the use of coal, natural gas, and oil [1]. Coal-fired power plants emit the highest CO 2 per unit of electric generating capacity [1], and despite the increased interest in green fuels [2][3][4], it is estimated that no other source of electricity will overtake coal until 2035 [1].…”

“…As the world population has grown, so has the demand for electrical generation, necessitating the use of coal, natural gas, and oil [1]. Coal-fired power plants emit the highest CO 2 per unit of electric generating capacity [1], and despite the increased interest in green fuels [2][3][4], it is estimated that no other source of electricity will overtake coal until 2035 [1]. As a result, coal will continue to play a key role in global energy supply for the foreseeable future [1,5].…”

“…Coal-fired power plants emit the highest CO 2 per unit of electric generating capacity [1], and despite the increased interest in green fuels [2][3][4], it is estimated that no other source of electricity will overtake coal until 2035 [1]. As a result, coal will continue to play a key role in global energy supply for the foreseeable future [1,5]. Continuous research on the clean and effective use of coal is still required and important.…”

A Pilot Plant Study of Coal Dryer: Simulation and Experiment

“…The coal quality also affects the quality of industrial products. For instance, the cement clinker product is affected by the temperature generated by coal combustion inside the kiln (Canbek and Erdoğan, 2020;Yang et al, 2021). Therefore, reducing the coal moisture content increases the coal quality to increase efficiency, heating rate, heating value, and industrial product quality.…”