掺混城市污泥对神木煤成浆特性的影响

Effect of mixed municipal sludge on slurryability of Shenmu coal

将城市污泥以不同质量比掺入神木煤制备污泥煤浆,利用安东帕C-LTD80/QC型旋转流变仪考察了污泥掺混质量比(α)对污泥煤浆的最大成浆浓度、流变性、触变性和稳定性等成浆特性的影响。借助FTIR和SEM表征煤、污泥及水煤浆,探讨掺混城市污泥影响神木煤成浆性能机制。结果表明:水煤浆及污泥煤浆流变特性均符合幂定律模型τ=Kγn,随着α的增大,污泥煤浆表观黏度增大,最大成浆浓度降低,浆体流变性指数n减小,剪切稀化特性明显,浆体更加趋向于假塑性流体;同时,α的增大也会使得浆体触变环面积增大,进一步导致浆体触变性增强;此外,加入污泥制备的污泥煤浆,浆体产生沉淀时间明显延长,其析水率与相同成浆浓度下的水煤浆的析水率相比明显降低,说明适当的污泥掺混量有利于改善浆体的稳定性。通过FTIR及SEM分析可知,污泥填充了煤粉颗粒之间的空隙,在浆体内部形成较强的空间结构,这种作用是导致掺混污泥后浆体的表观黏度增大、最大成浆浓度降低、稳定性提高的主要原因。在尽可能提高污泥掺混比例的条件下,当α为0.12,污泥煤浆的最大成浆浓度为60.42%时,浆体的成浆性能良好,满足工业要求。

Coal-sludge water slurry(CSS)was prepared with the mixture of Shenmu coal and municipal sludge in varying mass vatio.Based on this,the effect of sludge mixing mass ratio(α)on the slurry forming characteristics of CSS-such as maximum slurry concentration,rheology,thixotropy,and stability-was investigated in detail using Anton Paar’s C-LTD80/QC rotary rheometer.Furthermore,the coal,sludge,and coal-water slurry(CWS)were characterized by the use of FTIR and SEM while the influence mechanism of mixing sewage sludge on slurryability was discussed.The results show that,asαincreases,the apparent viscosity of CSS exhibits an upward trend,the maximum slurry concentration demonstrates a downward trend,both CWS and CSS exhibit rheological properties that conform to the power law modelτ=Kγn,and the rheological index(n)of the slurry decreases,showing a prominent shear thinning characteristic and a trend of transforming to pseudoplastic fluid.Meanwhile,the increase ofαalso increases the thixotropic ring area of slurry,which indicates that the addition of sludge can enhance the thixotropic of slurry.In addition,upon the addition of sewage sludge,the slurry exhibits a significantly prolonged precipitation time compared to CWS,and the water extraction rate of the slurry is notably lower than that of CWS at the same concentration,suggesting that proper sludge mixing is beneficial to improve the stability of slurry.Besides,the FTIR and SEM analyses show that the sludge occupies the interstitial spaces between the coal particles.This phenomenon results in the formation of a robust spatial structure within the slurry,which primarily accounts for the increase in apparent viscosity,decrease in maximum slurry concentration,and enhanced stability of the slurry after the addition of sludge.Under the condition of maximizing the proportion of sludge mixing,the slurry exhibits excellent performance at anαvalue of 0.12,with the maximum slurry concentration of CSS reaching approximately 60.42%,which meets the requirements of industrial.