High gas velocity in riser of circulating fluidized bed helps to improve fluidization quality of cohesive particles. However, in the dipleg of conventional CFB agglomerates formed in fluidizing process are going to deposit and block the particle returning route, which finally lead to CFB’s unstable operation. It is found in experiments that conical dipleg can maintain stable fluidization of cohesive particles. The addition of aeration gas to the V-valve significantly improves the V-valve’s capability of conveying particles from dipleg into riser. The combination of conical dipleg and the V-valve with aeration gas can achieve smooth returning of cohesive particles and making sure stable operation of CFB for cohesive particles.

Highly cohesive powders aggregate into wide-size-distribution fluidized agglomerates in fast bed, which can severely aggravate the fluidizing quality. In order to reduce the agglomerate size of highly cohesive powders in riser, “floating internals” are added into riser to cause the breakage of agglomerates. Floating internals are floated by the two-phase flow of gas and cohesive particles in riser. However, the floating internals should not be entrained into particle return system, and, should not have any reaction with powders or gas. Therefore the fast fluidization of cohesive particles with floating internals is different from the circulating fluidization of fine-coarse particle mixtures. Experiments on floating internals were conducted in a glass riser of 3.25m in height and 0.075m I.D, and four kinds of cohesive powders and floating internals were involved. Experimental results showed that appropriate matching of floating internals with cohesive particles could effectively avoid the formation of over-large agglomerates in the riser. A model has also been developed to predict the largest agglomerate size which floating internals could break under certain operating conditions. Comparing with experimental values, the predicted results of the model are reasonable and acceptable.

Experiments on fluidizing ultrafine and cohesive particles in a conical bed were conducted. The results showed that conical bed could satisfactorily fluidize not only low cohesive ultrafine particles but also highly cohesive powders, such as ultrafine CaCO3 powder which usually can not be fluidized in cylindrical bed. It was found that slugs, which usually appear at the initial stage of cohesive particle fluidization in cylindrical bed, were no longer present in conical bed. It was also found that there was a critical gas flow rate for all the cohesive powder tested, above which, the entire bed reached a steady fluidized state; while below which, either partial fluidization or total defluidization was observed for different powders. Improvement in fluidity and fluidizability of cohesive powders was identified by comparing pressure drop cures of first-time employed and many-times fluidized powders. In addition, there was a overshoot in the pressure drop vs. gas flow rate curve of highly cohesive powder in conical fluidized bed, which was similar to that of coarse particles in conical fluidized bed, while no overshoot appeared in the pressure drop vs. gas flow rate curve for mildly cohesive powder in conical fluidized bed, which was like that of the same powder in cylindrical fluidized bed.

研究了H2O和SO2对Mn−Fe/MPS催化剂NH3低温下选择性催化还原(SCR)NO的影响。结果表明，在反应温度低于413K时，水蒸汽(10%，φ)在一定程度上降低了催化活性；当反应温度超过433K时，这种影响可以完全消除，NO的SCR转化率达到97.8%以上。低浓度SO2(100×10−6)存在条件下，443K时催化效率仍可稳定在97.2%。在水和SO2共存的情况下，生成的硫酸盐和亚硫酸盐沉积在催化剂表面导致催化剂逐渐失活。提高选择性催化还原反应温度可以延缓催化剂的失活。此外还研究了不同活化温度对催化剂活性恢复的影响，结果表明，当活化温度达到773K时，催化剂的活性可以完全恢复。本研究中的催化剂在综合性能方面优于目前文献报道的其他催化剂。

A hydrodynamic model for an L-valve is proposed based on the theories of multiphase flow and particulate media mechanics. This model can be used to predict the solids flow rate, gas pressure drop, and gas flow rates, according to the properties of gas and solids, L-valve size, and the operational conditions. Predicted results agree well with the experimental data.