准东高钠煤流化床气化特性及钠的迁移规律研究

Fluidized Bed Gasification Performance and Sodium Transformation of Zhundong High Sodium Coal

基于小型立式炉试验台,对准东高钠煤在850~1050℃下的气化特性进行了研究,并对气化底渣及飞灰的理化特性进行了表征。研究表明:准东高钠煤在气化当量比不变的情况下,随气化反应温度升高,煤气中可燃成分CO、H_2体积百分比增大,煤气热值、碳转化率、冷煤气效率也均增大。气化反应温度为1050℃时,煤气热值为4.27MJ/m^3,碳转化率为89.07%,冷煤气效率为70.01%。SEM结果显示气化底渣、飞灰表面呈沟壑状,未出现明显熔融。XRD结果显示气化飞灰中钠主要以NaCl和NaAlSi_2O6的形态存在,底渣中钠主要以NaAlSi_2O_6的形态存在。气化过程中钠的析出率随温度升高呈先增后减趋势:气化温度由850℃升至1000℃时,钠的析出率由20.49%升高至53.64%;而气化温度由1000℃继续升高至1050℃时,钠的析出率略有下降,由53.64%降至52.22%。

Based on the vertical tube furnace apparatus,the gasification performance of Zhundong high sodium coal was studied under temperature ranging 850~1050℃,and the physical and chemical characteristics of bottom chars and fly ashes were characterized.The results show that as the gasification equivalent ratio kept constant,the concentrations of CO and H_2 in fuel gas,the LHV of the fuel gas,the carbon conversion and cold gas efficiency all increased with the rise of the gasification temperature.At 1050℃,the LHV of the fuel gas was 4.27 MJ/m^3,the carbon conversion was 89.07%,and the cold gas efficiency was 70.01%.The SEM images show that the gasification bottom chars and fly ashes are granular with striped ravines,and there is no agglomeration phenomenon occurred.XRD results show that sodium mainly presents as NaCl and NaAlSi_2O_6 in the fly ashes,while as NaAlSi_2O_6 in the bottom chars.With the increase in temperature,the sodium release ratio first increases and then decreases.As gasification temperature rises from 850℃ to 1000℃,the sodium release ratio increases from 20.49%to 53.64%.However,when gasification temperature further rises from 1000℃ to 1050℃,the sodium release ratio decreases slightly from 53.64%to 52.22%.