【作者】 杨秀山； 夏巍； 何勇； 孔行健； 张志业； 王辛龙；

【Author】 YANG Xiushan;XIA Wei;HE Yong;KONG Xingjian;ZHANG Zhiye;WANG Xinlong;College of Chemical Engineering,Sichuan University;

【机构】 四川大学化学工程学院；

【摘要】 磷石膏是磷肥工业固体废弃物,当前磷石膏巨量堆积,不仅占用大量土地,还严重污染生态环境,且其蕴藏的硫资源未能得到利用。通过硫磺流化分解磷石膏制硫酸是具备显著应用前景的一种磷石膏资源化利用的技术。然而该技术难点在于粘性磷石膏颗粒的散式流化,因此探索粘性磷石膏颗粒的流化特性对于该技术的发展具有重要理论意义。本文采用了添加粗颗粒改善磷石膏颗粒流化质量的方法,在自建流化床装置中进行了添加石英砂与硫精砂对粘性磷石膏颗粒流化特性影响的实验研究。结果表明单一组分的磷石膏颗粒(平均粒径20~40μm)不能形成良好的散式流化,易出现柱塞、沟流等现象。而单一组分的石英砂以及硫精砂颗粒(粒径150~380μm)流化效果良好。向磷石膏颗粒中添加石英砂或硫精砂后,其流化性能得到明显改善。当石英砂与硫精砂添加量分别为60%和50%时能实现很好的流化。在实验研究基础上分析了粘性磷石膏颗粒聚团机理,并运用周-李模型计算了粘性磷石膏颗粒聚团尺寸。结果表明在添加粗颗粒后,磷石膏颗粒的流化聚团尺寸要小很多,充分说明了粗颗粒加入后对原有磷石膏颗粒聚团的破碎和切割作用。实验和计算结果均表明添加粗颗粒是改善粘性磷石膏颗粒流化质量的有效方法。更多还原

【Abstract】 Phosphogypsum(PG) is a solid waste of phosphate fertilizer industry. A huge amount of PG which was stacked not only occupied a lot of lands, but also polluted ecological environment seriously. And the sulfur resources in the PG weren’t be utilized. In recent years, the situation that shortage of sulfur resources has not eased in China. At the same time, phosphate fertilizer industry is still the industry department that consumes the most of sulfur resources in China. Utilization of sulfur resources in PG has an obvious effect of circular economy. It has become an inevitable choice. Fluidized decomposition of PG to produce sulfuric acid by sulfur is a technology that has a significant application prospect. However, difficulty of this technology is the particulate fluidization of cohesive PG powders. So investigation on the fluidized characteristic of cohesive PG powders has an important theoretic significance for the technology development of PG fluidized decomposition by sulfur. Considering the particle characteristic of PG, this paper proposed a method to improve the fluidization quality of cohesive PG powders through adding coarse particles. Experiment investigation on the fluidized characteristic of cohesive PG powders by adding quartz sands and pyrite concentrates was conducted in the self-build fluidized bed equipment. The results showed that single component PG powders(average diameter 20-40μm) can’t achieve good dispersion fluidization, the phenomenon of plunger and channeling would easily occur in the process. However, single component quartz sands and pyrite concentrates(particles size 150-380μm)have a good state of fluidization. Fluidization quality of PG powders was better with the increasing of additive proportion of coarse particles in the binary mixed system of PG powders with quartz sands or pyrite concentrates. PG powders achieved incipient fluidization when the additive proportion of quartz sands and pyrite concentrates were respectively 50wt% and 30wt%.Pyrite concentrate is a better additive than quartz sand for the fluidization of PG powders. PG powders can achieve good particulate fluidization when the additive proportion of quartz sands and pyrite concentrates were respectively 60wt% and 50wt%.Pressure fall-off curve of increasing flow rate and decreasing flow rate can achieve a good coincidence at this additive proportion.PG powders can achieve the best particulate fluidization when particles size of quartz sands and pyrite concentrates are both150-200μm at the same additive proportion. Aggregating mechanism of cohesive PG powders was analyzed on the basis of experimental research. And agglomeration sizes of PG powders were calculated by Zhou-Li model. The calculation results showed that fluidized agglomeration sizes of PG powders are much smaller after adding quartz sands and pyrite concentrates. It is quite good explanation on the broken and cut effect of coarse particles for PG powders. Single fluidized agglomeration sizes of PG powders were 1858μm at the apparent gas velocity of 0.24m/s. Fluidized agglomeration sizes of the binary mixed system that PG powders with 60wt% quartz sands(particles size 250-380μm) or 50wt% pyrite concentrates(particles size 180-250μm) were respectively 329μm and 628μm at the apparent gas velocity of 0.05m/s. Both of the experiment and calculation results showed that adding particles is an effective method for improving the fluidized quality of cohesive PG powders.更多还原