Effects of Hydrocarbon Liquid Feed in Polyethylene Polymerization Process on Particle Surface Temperature

Botros, K. K.; Price, G. R.; Ker, V.; Jiang, Yabin; Goyal, S. K.

doi:10.1080/00986440600586511

Cited by 9 publications

(8 citation statements)

References 10 publications

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“…Collisions between small particles occur much more frequently than between coarse particles. , What is more, as the heat transfer coefficient of small particles is higher, their surface temperature tends to increase rapidly after being injected into beds . In the gas phase olefin polymerization, small particles in the bed generally have higher catalytic activity and heat producing rate. , The “overheating” phenomenon usually occurs among small particles and consequently the polymer generated on their surface becomes soft and sticky. During collisions, particles could easily form a solid bridge on their contact surface, which is commonly interpreted as “sintering”, and if the strength of solid bridge between particles is strong enough, particles coalescence would occur and agglomerates would be generated.…”

Section: Introductionmentioning

confidence: 99%

Experimental Investigation of Particle Size Effect on Agglomeration Behaviors in Gas–Solid Fluidized Beds

Wang

Shi

Huang

et al. 2015

Ind. Eng. Chem. Res.

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A novel induction heating apparatus is designed to mimic the exothermic process in an olefin polymerization gas–solid fluidized bed. Wax/graphite composites with core–shell structure are used as tracer particles to capture the agglomerates formed in the cold mode experiments. Pressure fluctuation sensors and image analysis methodology are used to characterize the detailed information on agglomerates such as mass, size, and compositions. Experimental results reveal that when the mass fraction of tracer particles is above 10%, agglomerates are formed in the fluidized bed. Compared with coarse particles, small particles lead to agglomeration much easier, and coalescence of small–small particles or small–coarse particles is the main mechanism by which agglomeration occurs. Analyzing the collision process of small particles and coarse particles, we conclude that collisions among small particles or collisions between small and coarse particles are more frequent and efficient than that of coarse particles.

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Section: Introductionmentioning

confidence: 99%

Experimental Investigation of Particle Size Effect on Agglomeration Behaviors in Gas–Solid Fluidized Beds

Wang

Shi

Huang

et al. 2015

Ind. Eng. Chem. Res.

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“…There are many factors that can impact the softening temperature, such as co‐polymer composition of the polymer, polymer density or presence of an ICA. [ 8,70,73 ] In addition, one might ask if the softening temperature is in fact the best indication of stickiness, and several patents discussed by McKenna [ 5 ] cite the melt initiation, or melt onset temperature, as the most important indication of stickiness. Like the softening temperature, this value will also be a function of polymer density, degree of swelling and eventually MWD.…”

Section: Macroscale Modelingmentioning

confidence: 99%

“…In normal condensed mode, it has been shown that the liquid droplets evaporate rapidly, and that the clear majority of the powder bed in a typical reactor contains only solid particles and a continuous gas phase. [ 7,8 ] On the other hand, adding an ICA has a much more significant effect on the observed rate of polymerization that cannot be exclusively explained by better heat evacuation. It turns out that the well‐known co‐solubility effect implies that the concentration of ethylene in the polymer amorphous phase is increased by the presence of a heavier hydrocarbons.…”

Section: Introductionmentioning

confidence: 99%

Gas‐Phase Polyethylene Reactors—A Critical Review of Modeling Approaches

Alves

Casalini

Storti

et al. 2021

Macro Reaction Engineering

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Different approaches to modeling the gas phase polymerization of ethylene that have been considered in the literature are reviewed. It is shown that while simple, well‐mixed models can give an adequate representation of the average performance of a given polymerization reactor, they do not allow one to analyze certain modeling problems such as the existence of temperature gradients or particle segregation, nor can they be used to treat operational modes such as condensed cooling where there can be up to three different phases in different parts of the reactor. For this, more complex models are required. These can take the form of compartmentalized models or even models based on computation fluid dynamics. However, long computational times can be required to fully exploit these models. Furthermore, significant progress needs to be made if one needs to address important phenomena such as agglomeration or particle attrition during polymerization.

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“…Although the liquid film formation cannot be observed directly from our opaque apparatus, it is commonly considered in the literature that liquid sprayed into the fluidized bed all adheres to particles to form liquid films, based on which the mass and heat transfer properties are calculated, and the results are reasonable and consistent well with the measured data. 32,33 In addition, the collision frequency between particles and liquid droplets in such a dense-phase fluidized bed is quite high (∼10 5 ), and droplets are difficult to exist separately and highly possible to collide with and adhere to particles. Therefore, in this work, we employ the liquid film formation hypothesis and believe it reasonable.…”

Section: Industrial and Engineering Chemistry Researchmentioning

confidence: 99%

Dynamic and Steady-State Characterization of the Liquid Spray Zone in an Externally Heated Gas–Solid Fluidized Bed

Sun

Huang

et al. 2018

Ind. Eng. Chem. Res.

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In industrial fluidized beds with liquid spray, dynamic and steady-state characteristics of the liquid spray zones are of significant importance for operation optimization and products control. In this study, a conductivity probe array, two thermocouple arrays, and a pressure sensing system are applied to an externally heated gas–solid fluidized bed with a side-wall liquid spray. Nonstationary and nonlinear characteristics are exhibited in the Hilbert spectra of the conductivity probe signals, and the fluctuation energy distribution shifts to higher frequencies with the liquid spray velocity, related to the liquid-induced higher-frequency bubble motion. The variation coefficient analysis of temperature data is a reliable approach to characterizing the liquid spray zone boundary. The liquid spray zone is enlarged and extends downward along the wall with the liquid spray velocity and shrinks with the gas velocity. Moreover, the liquid spray zone is enlarged and extends downward along the wall with the nozzle installation height.

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Effects of Hydrocarbon Liquid Feed in Polyethylene Polymerization Process on Particle Surface Temperature

Cited by 9 publications

References 10 publications

Experimental Investigation of Particle Size Effect on Agglomeration Behaviors in Gas–Solid Fluidized Beds

Experimental Investigation of Particle Size Effect on Agglomeration Behaviors in Gas–Solid Fluidized Beds

Gas‐Phase Polyethylene Reactors—A Critical Review of Modeling Approaches

Dynamic and Steady-State Characterization of the Liquid Spray Zone in an Externally Heated Gas–Solid Fluidized Bed

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