Modeling of complex liquid-solid flow of particle swelling in slurry loop reactors. (2nd February 2018)

• Record Type: Journal Article
• Authors: Zhou, Rongtao; Chen, Jianhua; Yang, Ning; Li, Jinghai; Fernandez, Alvaro; Ricoux, Philippe
• Is Part Of: Chemical engineering science. Volume 176(2018)
• Page Start: 476
• Page End: 490
• Publication Date: 2018-02-02
• Subjects: CFD simulation -- PBE -- Polyethylene -- Swelling -- Loop reactor -- Mesoscale; Chemical engineering -- Periodicals; Génie chimique -- Périodiques; Chemical engineering; Periodicals; Electronic journals; 660
• DOI: 10.1016/j.ces.2017.11.012
• Languages: English
• ISSNs: 0009-2509

Abstract

Highlights: Particle swelling has significant influence on PE reactor operation. A heuristical model is developed to consider the aggregation of swelling particles in TFM. It captures the gradual increase of power consumption due to swelling in stirred tanks. It predicts slug formation and a sharp increase of power consumption in slurry loop reactors. It serves as a new way for reactor optimization. Abstract: A swelling-dependent two-fluid model (STFM) is developed for the liquid-solid flows of swelling particles in polyethylene reactors. The model integrates the two-fluid model (TFM) with a species transport equation (STE) to account for the diffusion of alkane molecules from the liquid bulk to the amorphous region of particles, and a population balance equation (PBE) to consider the aggregation of swelling particles. Simulations show that only the TFM fails to capture the main features of swelling systems. By contrast, the STFM captures the gradual increase of power consumption due to particle swelling and aggregation, which agrees with the experiments in a stirred tank. The STFM predicts also the slug formation and a sharp increase of power consumption in a slurry loop reactor as well as the solid accumulation behind pump. The difference of model prediction for stirred tanks and loop reactors suggests the potential of reactor optimization by enhancing local mixing while still keeping high solid concentration for productivity.