Meta-study on the effect of P2O5 on single phase slag viscosity and the effect of P2O5 induced liquid phase immiscibility on dispersion viscosity

FUEL

卷:305

Article

Schwitalla, Daniel Harry¹  Guhl, Stefan¹  Koerner, Justyna¹  Laabs, Marcel¹  Bai, Jin²  Meyer, Bernd^1,2 

[1] TU Bergakad Freiberg, Inst Energy Proc Engn & Chem Engn IEC, Fuchsmuhlenweg 9, D-09599 Freiberg, Germany

[2] Chinese Acad Sci, Inst Coal Chem, State Key Lab Coal Convers, Taiyuan 030001, Peoples R China

关键词: Sewage sludge;    Phosphorous oxide;    Gasification;    Slag viscosity;    Thermochemistry;   

DOI  :  10.1016/j.fuel.2021.121501

来源: Elsevier

【 摘 要 】

Investigations on the viscosity behavior of gasification slags with special respect to P2O5 are scarce. Therefore, a meta study was performed compiling the relevant knowledge on its effect on the viscosity of melt compositions similar to gasification slags. The data showed whether the oxide behaves acidic and as a network former and how its behavior changes with varying basicity of a single-phase melt. A supplementary study was performed since a previous paper showed a viscosity anomaly on a P2O5 bearing slag that is included in the meta study. In order to investigate the phenomenon, quench analyses were performed and the slag was investigated via XRD and SEMEDX. The viscosity anomaly was found to be caused by a miscibility gap at a certain temperature. A miscibility gap is quite common in P2O5 bearing slags. The two resulting phases showed a clear difference in composition but could be well predicted via FactSage 7.2. The FactSage model could be modified so that it worked in the case of undercooling. An average relative error of only 18 to 20 % for the main oxides was found at temperature points without undercooling.

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