气化灰渣凝胶泡沫特性及防灭火性能

Characteristics and fire resistance of gel foam of gasification ash residue

为研究气化灰渣凝胶泡沫对煤的阻化作用,从微观角度探讨了凝胶剂对气化灰渣凝胶泡沫稳定性的影响,宏观比较了3种不同类型凝胶泡沫的形貌特征与煤表面覆盖的成膜效果,通过测量材料在不同水灰比下的流变特性,分析气化灰渣颗粒对凝胶泡沫的黏度、剪切应力和屈服应力的影响,最后利用程序升温试验和热重试验研究了气化灰渣凝胶泡沫的防灭火性能。结果表明:适当的凝胶剂浓度有利于维持泡沫稳定存在,当添加胶凝剂浓度为0.6%时,凝胶泡沫的显微形貌和基本参数最佳;气化灰渣凝胶泡沫覆盖在煤表面的成膜效果最好,经过7 d后在煤表面仍可形成完整的保护膜;随着水灰比的降低,凝胶泡沫的剪切应力和黏度逐渐增加,水灰比为2∶1时泡沫更不易流动;经气化灰渣凝胶泡沫处理后煤样的临界温度T1提升至72℃,干裂温度T2提高了30℃,有效抑制煤氧化进程,且100℃时泡沫的阻化率达到了63.6%。这种新型泡沫防灭火技术为煤自燃防治提供了新的可能,为固废资源化利用提供了新思路。

In order to study the effect of gelling foam on coal inhibition,the influence of gelling agent on the stability of gelling foam was discussed from the microscopic point of view,and the morphology characteristics of three different types of gel foam were compared with the film forming effect of coal surface covering.The effects of ash particles on the foam viscosity,shear stress and yield stress of gel foam were examined by measuring the rheological properties of materials at different watercement ratios.And the firefighting performance of the gel foam was studied by temperature programmed experiment and thermogravimetric experiment.The results show that the appropriate gel concentration is conducive to the stable existence of the foam.When the concentration of gelling agent is 0.6%,the micro-morphology and basic parameters of the gel foam are the best.The film forming effect of gel-foam covering coal surface is the best,and a complete protective film can still be formed on coal surface within 7 days.With the decrease of water-cement ratio,the shear stress and viscosity of the gel foam gradually increase,and the foam is more difficult to flow when the watercement ratio is 2∶1.The critical temperature T1 increased to 72℃and the cracking temperature T2 increased by 30℃,which effectively inhibite the coal oxidation process.At 100℃,the inhibition rate of the foam reaches 63.6%.This new foam fire prevention technology provides a new possibility for coal spontaneous combustion prevention and control,and a new idea for solid waste resource utilization.