与其他回转窑相比,伊朗南部的 Sarcheshmeh 石灰回转窑消耗了大量的热能。因此,正在研究 Sarcheshmeh 石灰窑以提高能源消耗的潜力。本文使用了实验数据和 CFD 模拟。对三种模式进行了数值模拟,研究了石灰窑能耗的问题和解决方案:设计模式、运行模式和运行条件变化的影响。在最后一种模式中,研究讨论了过量空气百分比、一次与二次空气流量比、一次空气流量、水分和石灰石粒度五个参数。考虑石灰窑运行的不同因素,数值模拟考虑了燃烧器中燃料燃烧、石灰石煅烧和颗粒运动的所有三种主要现象。质量和能量平衡的运行条件测量表明,从二次空气入口到燃烧器头的吸入空气不足。这是由于窑的初始长度部分多次泄漏,最终导致不完全燃烧和燃料浪费。根据 CFD 模拟,降低进水石灰石颗粒的尺寸会增强石灰石的煅烧。此外,如果生石灰的最高温度受到限制,可以使用较高的一次气流与二次气流的比率,在这种情况下,石灰石在窑出口处转化为生石灰的程度保持不变。质量和能量平衡的运行条件测量表明,从二次空气入口到燃烧器头的吸入空气不足。这是由于窑的初始长度部分多次泄漏,最终导致不完全燃烧和燃料浪费。根据 CFD 模拟,降低进水石灰石颗粒的尺寸会增强石灰石的煅烧。此外,如果生石灰的最高温度受到限制,可以使用较高的一次气流与二次气流的比率,在这种情况下,石灰石在窑出口处转化为生石灰的程度保持不变。质量和能量平衡的运行条件测量表明,从二次空气入口到燃烧器头的吸入空气不足。这是由于窑的初始长度部分多次泄漏,最终导致不完全燃烧和燃料浪费。根据 CFD 模拟,降低进水石灰石颗粒的尺寸会增强石灰石的煅烧。此外,如果生石灰的最高温度受到限制,可以使用较高的一次气流与二次气流的比率,在这种情况下,石灰石在窑出口处转化为生石灰的程度保持不变。最终导致不完全燃烧和燃料浪费。根据 CFD 模拟,降低进水石灰石颗粒的尺寸会增强石灰石的煅烧。此外,如果生石灰的最高温度受到限制,可以使用较高的一次气流与二次气流的比率,在这种情况下,石灰石在窑出口处转化为生石灰的程度保持不变。最终导致不完全燃烧和燃料浪费。根据 CFD 模拟,降低进水石灰石颗粒的尺寸会增强石灰石的煅烧。此外,如果生石灰的最高温度受到限制,可以使用较高的一次气流与二次气流的比率,在这种情况下,石灰石在窑出口处转化为生石灰的程度保持不变。
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Investigating the potentials to improve the energy consumption of a lime rotary kiln using measurement and CFD simulation
Sarcheshmeh lime rotary kiln in the south of Iran consumes a lot of thermal energy compared with other rotary kilns. As a result, Sarcheshmeh lime kiln is being investigated for the potential to improve energy consumption. Experimental data and CFD simulation are both used in this paper. The numerical simulation has been performed for three modes to investigate the problems and solutions of energy consumption in the lime kiln: design mode, operation mode, and effect of operating condition changes. In the last mode, five parameters including the percentage of excess air, the ratio of primary to secondary air flow, primary air flow, moisture, and particle size of limestone are studied and discussed. To consider different factors of lime kiln operation, the numerical simulation takes into account all three major phenomena of fuel combustion in the burner, limestone calcination, and particle movement. Operating conditions measurements with mass and energy balances show that there is insufficient suction air from the secondary air inlet to the burner head. This is due to multiple leaks from the kiln's initial length part, resulting in incomplete combustion and fuel waste eventually. According to CFD simulation, lowering the size of the intake limestone particles enhances the calciantion of limestone. Also, if quicklime's maximum temperature is limited, a higher ratio of primary to secondary airflow can be used, in which case the degree of conversion of limestone to quicklime at the kiln exit remains constant.