Viscosity determination of the biomass slag in the SiO2-CaO-K2O system based on the bond distribution

• Published in: Fuel (Guildford) 2024-01, Vol.356, p.129642, Article 129642
• Main Authors: He, Chong, Fan, Feifei, Guo, Jing, Yuan, Mengran, Qin, Yuhong, Wei, Yuexing, Yan, Jingchong
• Format: Article
• Language: English
• Subjects: Biomass gasification; Bond distribution; SiO2-CaO-K2O system; Slag tapping process; Viscosity prediction
• ISSN: 0016-2361
• DOI: 10.1016/j.fuel.2023.129642

•A convenient viscosity model for the biomass slag (SiO2-CaO-K2O system) is firstly proposed.•Slag structure is characterized by the distribution of Si-Si-O-O bond, Si-Ca-O-O bond, and Si-K-O-O bond.•Relation between bond distribution and the activation energy of viscous flow is quantified.•Superior predictability of proposed model than the FactSage model is found in 2.5–25 Pa·s. The slag mobility is a key factor influencing the slag tapping process during the slagging gasification of biomass. However, the viscosity model suitable for the biomass slag (relevant to the SiO2-CaO-K2O system) has not been reported yet. This study firstly proposed an Arrhenius-type viscosity model based on the bond distribution in biomass slag. The bond information of the biomass slag was determined by61 thermodynamic modelling. The quantified relation between the slag composition (SiO2, CaO, and K2O) and bond distribution (Si-Si-O-O, Si-Ca-O-O, and Si-K-O-O), and the relation between the bond distribution and activation energy of viscous flow (Ea) or pre-exponential factor (A) were established, respectively. The standard deviations of our model are 1.71 Pa·s in the 0–100 Pa·s and 0.61 Pa·s in the 2.5–25 Pa·s, respectively. The newly built viscosity model shows superior prediction performance than the empirically viscosity models, and owns better performance than the FactSage model in the optimal viscosity range (2.5–25 Pa·s) of the smooth slag tapping process.