Oxy-fuel combustion is an efficient combustion technology that uses an oxidant with a higher oxygen content than air, which can effectively shorten the coal combustion time and improve Pulverized coal burner combustion efficiency and combustion temperature. In recent years, membrane oxygen production technology has been developed and utilized, greatly reducing the cost of oxy-fuel combustion technology. The combustion temperature of pulverized coal depends on the oxygen concentration around the pulverized coal particles. 1 Oxy-fuel combustion technology renovation measures ： The overall renovation of oxy-fuel combustion technology inside the kiln is divided into the firing system and the oxygen production and supply system. A new deep-cold direct delivery method is used to produce oxygen-enriched air. ， Oxygen-enriched air is introduced into the dry-process cement rotary kiln as primary air through the multi-channel burner at the kiln head.

Impact of oxy-fuel combustion on kiln system ： Oxy-fuel combustion inside the kiln is an efficient enhanced combustion technology that significantly increases the pulverized coal combustion temperature and shortens the burnout time, concentrating the heat release of pulverized coal. Shortening the residence time of gas in the high-temperature zone ensures the firing temperature inside the kiln. After the oxy-fuel combustion modification inside the kiln, coal is fully combusted in the oxygen-enriched state, which increases the flame blackness, enhances heat transfer inside the kiln, and improves the system's heat utilization rate. In addition, the increased temperature inside the kiln leads to an increase in liquid phase, making the kiln crust stable and uniform, reducing the kiln's rotational torque, and lowering the kiln's operating current.

Impact of oxy-fuel combustion on preheater system ： After the implementation of oxy-fuel combustion, the preheater pressure loss and exhaust gas volume decreased, and the outlet pressure changed from the original -5600Pa reduced to -5320Pa ; the outlet exhaust gas volume changed from 1.360Nm³/kg.cl reduced to 1.306Nm³/kg.cl . The reduction in exhaust gas volume at the preheater outlet indicates a decrease in air consumption by the firing system.

Oxy-fuel combustion inside the kiln uses oxygen-enriched air as a combustion aid, reducing the excess air coefficient while meeting the requirements for pulverized coal combustion, thereby reducing the amount of flue gas generated. The reduction in exhaust gas expelled from the system also leads to a decrease in system heat loss caused by exhaust gas. At the same time, due to the reduced air consumption of the system, the wind speed in each cyclone is lowered, and the system resistance is also reduced. This improves the system's firing efficiency and reduces energy consumption.

Impact of oxy-fuel combustion on grate cooler system ： After the implementation of oxy-fuel combustion, the secondary and tertiary air temperatures increased, and the system's heat recovery efficiency improved by 1.6 %, and the clinker temperature remained basically unchanged. The heat recovery efficiency of the grate cooler is mainly affected by the secondary and tertiary air temperatures and air volume. When pulverized coal burns in an oxygen-enriched state, the increased flame temperature and blackness improve the material heat transfer efficiency, resulting in higher clinker temperature exiting the kiln, and forming higher temperature secondary and tertiary air in the high-temperature cooling zone of the grate cooler. In addition, after oxy-fuel combustion, the air consumption of the firing system decreases, and the cooling air volume of the grate cooler decreases by approximately 11 %, while the secondary and tertiary air decreased by only about 3.9 %. It is clear that oxy-fuel combustion can effectively improve the operational performance of the grate cooler.

Impact of oxy-fuel combustion on energy saving and consumption reduction in the firing system ： Oxy-fuel combustion technology uses oxygen-enriched air as a combustion aid, shortening the pulverized coal burnout time, increasing pulverized coal combustion temperature, improving heat exchange efficiency of materials inside the kiln, and reducing the pulverized coal consumption required to complete clinker firing inside the kiln; it also increases the secondary and tertiary air temperatures, which is more conducive to heat recovery, thereby reducing the system's heat consumption. According to statistical data from post-modification operation, the firing coal consumption decreased by approximately 5.0kg.ce/t.cl ; in addition, after the implementation of oxy-fuel combustion technology, the kiln condition became more stable, the kiln lining was stable and uniform, the kiln current significantly decreased, oxy-fuel combustion reduced the excess air coefficient, reduced the amount of flue gas generated, decreased the outlet exhaust gas volume, reduced heat loss and fan power consumption, and the comprehensive power consumption for clinker decreased by approximately 2.0kWh/t.cl . If the power consumption of the oxygen production system is included, the comprehensive power consumption for clinker increases by 1.5 to 2kWh/t.cl。

Conclusion ， In the 5000t/d clinker production line, oxy-fuel combustion technology was practiced, achieving good energy-saving and consumption-reducing effects: the thermal efficiency of the firing system improved, air consumption decreased, and system resistance decreased; the coal consumption for the firing system decreased by approximately 5.0kg.ce/t.cl ; including the power consumption of the oxygen production system, the comprehensive power consumption for clinker increased by approximately 1.5 to 2kWh/t.cl。

For cement clinker calcination kilns, Zhengzhou Zhongwei Environmental Protection Equipment Co., Ltd. undertakes domestic and international projects: multi-channel pulverized coal burners, 、 natural gas burners, 、 diesel heavy oil rotary kiln burners, 、 DCS systems and high-temperature industrial television, cement kiln denitration equipment engineering projects.

Address: No. 118, Fengqing Road, Jinshui District, Zhengzhou City
Tel:+86-371-60960056
Mobile:+8613849187223
Email:zhongweigongyelu@126.com