超声空化-流体剪切协同强化油团聚分选煤气化细渣

Enhanced oil agglomeration separation of coal gasification fine slag by ultrasonic cavitation-fluid shear

煤气化细渣(CGFS)具有较高的利用价值,但残炭回收率低极大地制约了其资源化利用。油团聚分选法在CGFS分选过程中具有明显优势,但炭灰共生结构严重限制了油团聚分选效率。为突破油团聚法分离富集残炭技术的瓶颈问题,考察了超声时间、超声功率、流体剪切时间及其交互作用对油团聚分选效果的影响,并结合BET、粒度分布、FT-IR、XPS以及SEM-EDS等分析手段,揭示了超声空化-流体剪切(UC-FS)协同预处理对油团聚分选效果的强化机理。结果表明:当超声功率为270 W、超声处理时间29 min、流体剪切时间23 min时,能分选得到灰分为9.55%的精矿、灰分为91.51%的尾矿,可燃体回收率可提高至90.54%。超声空化作用使原本致密的炭灰结构逐渐松散,与流体剪切的冲刷作用协同促进CGFS的孔隙结构的发展,使炭灰颗粒解离度增加,从而降低了精矿灰分。UC-FS协同预处理能够有效增加残炭表面C—C、C=C以及C—H等疏水基团的比例,使其接触角由110.34°增加到121.16°,扩大了炭和灰颗粒表面疏水性差异,提高了油团聚分选的效果。UC-FS协同预处理使炭灰颗粒高效分离的强化作用主要归因于超声空化气泡与细粒微球耦合产生的微磨料效应。可为实现CGFS分质资源化利用提供理论基础和技术指导。

Coal gasification fine slag(CGFS)has high utilization value,but the low recovery rate of residue carbon greatly restricts its resource utilization.The oil agglomeration separation method has obvious advantages in the CGFS separation process,but its separation efficiency is severely limited by the symbiotic structure of carbon and ash.In order to break through the bottleneck problem of residue carbon separation and enrichment technology by oil agglomeration method,the effects of ultrasonic time,ultrasonic power,fluid shear time and their interaction on oil agglomeration and separation were investigated in this paper.Combined with BET,particle size distribution,FT-IR,XPS and SEM-EDS analysis methods,the strengthening mechanism of ultrasonic cavitation and fluid shear(UC-FS)pretreatment on oil agglomeration separation was revealed.The results show that when the ultrasonic power is 270 W,the ultrasonic treatment time is 29 min,and the fluid shear time is 23 min,the concentrate with ash content of 9.55%and the tailings with ash content of 91.51%can be obtained,and the combustible recovery rate can be increased to 90.54%.Ultrasonic cavitation gradually loosens the ori-ginal dense carbon ash structure,and promotes the development of the pore structure of CGFS in coordination with the scouring effect of fluid shear,which increases the dissociation degree of carbon ash particles and thus reduces the ash con-tent of concentrate.UC-FS pretreatment can effectively increase the proportion of hydrophobic groups such as C-C,C=C and C-H on the surface of carbon residue,increase its contact angle from 110.34°to 121.16°,and further expand the difference of hydrophilic and hydrophobic properties on the surface of carbon and ash particles,thus improving the ef-fect of oil agglomeration separation.The mechanism of UC-FS synergistic pretreatment to improve the efficient separa-tion of carbon ash particles is mainly attributed to the micro-abrasive effect generated by the coupling of ultrasonic cavita-tion bubbles and fine-grained microspheres.This study can provide theoretical basis and technical guidance for the separa-tion and utilization of CGFS.