CFD investigations of particle segregation and dispersion mechanisms inside a polyolefin 8-leg loop reactor of industrial scale

Li, Yuehao; Ma, Yongting; Reddy, Rupesh K.; Vijay, Sameer; Elovainio, Erno; Wurnitsch, Christof; Nandakumar, K.

doi:10.1016/j.powtec.2015.06.031

Cited by 11 publications

(9 citation statements)

References 14 publications

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“…One challenge confronted by the slurry-phase polymerization technique is the frequent formation of polymer slugs. As shown in our previous study, the 180° bends or 90° elbows used by the loop reactors can induce the solid segregation mechanism that stratify polymer particles into particulate ropes . After the loop reactors are operated for sufficiently long time, these particulate ropes eventually develop into polymer slugs .…”

Section: Introductionmentioning

confidence: 61%

“…A transport equation is adopted to estimate the granular temperature Θ s throughout the domain as well as time: in which k Θ s is the diffusion coefficient for the granular temperature, which is estimated by the Symlal’s model, γ Θ s is the collisional dissipation of energy derived by Lun et al, ϕ ls is the energy exchange in particle velocity between the solid and liquid phases, which is estimated by Gidaspow’s model . The detail expressions of these parameters can be found in our previous papers. , …”

Section: Methodsmentioning

confidence: 99%

“…The reactor consists of eight vertical legs, seven 180° bends, and two 90° bends. The detailed geometry of the loop reactor has been presented in our previous work. , The patent indicates that this reactor is capable of producing about 4.0 × 10 4 kg PE per hour . The inner diameter of all the pipes ( D 1 ) is 0.56 m (22 in.…”

Section: Reactor Geometry and Operating Parametersmentioning

confidence: 99%

“…As shown in our previous study, the 180°bends or 90°elbows used by the loop reactors can induce the solid segregation mechanism that stratify polymer particles into particulate ropes. 4 After the loop reactors are operated for sufficiently long time, these particulate ropes eventually develop into polymer slugs. 5 Once the polymer slugs are formed, the solid dispersion mechanism inside the loop reactors cannot dissipate them effectively.…”

Section: Introductionmentioning

confidence: 99%

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Optimal Design of Bypass Line for an Industrial-Scale 8-Leg Polyolefin Loop Reactor to Manage Slurry Dispersion Using Hydraulic and CFD Simulations

Reddy

et al. 2018

Ind. Eng. Chem. Res.

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The pump power oscillation caused by slugs in slurry phase polymerization reactors limits production capacity. A bypass line connecting two locations of a loop reactor is suggested in patent literature to dissipate slugs. The optimal design of such bypass lines is studied through a hierarchy of modeling approaches applied to an industrial-scale reactor. In the design process, 1D hydraulic calculations guide the selection of optimal bypass pipe sizes to maximize slurry velocity. 2D CFD simulations provide data on slug dissipation processes. 3D simulations guide selection of optimal installation angle to maximize solid intake into the bypass line. By combining these approaches, a bypass line connecting the second and sixth legs by 6 in. pipes at a 45°angle is found to be optimal for reactor considered here. Such designs achieves high slurry velocity in the bypass line while maximizing slug dissipation, and the approach is applicable for other loop reactor configurations.

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Section: Introductionmentioning

confidence: 61%

Section: Methodsmentioning

confidence: 99%

Section: Reactor Geometry and Operating Parametersmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Optimal Design of Bypass Line for an Industrial-Scale 8-Leg Polyolefin Loop Reactor to Manage Slurry Dispersion Using Hydraulic and CFD Simulations

Reddy

et al. 2018

Ind. Eng. Chem. Res.

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“…Yan et al [17] studied the influences of guide vane on solid-liquid two-phase flows in a loop reactor under the same conditions by using the same physical model and analysis method as Shi [16]. Li et al [18] analysed the fluctuations of speed, pressure, and solid volume fraction based on the transient Eulerian-Eulerian model when the solid volume fraction is 0.23. However, the mixture of high-concentration solidphase polypropylene and liquid-phase propylene could not maintain the physical properties of Newtonian fluid, but showed properties of Bingham fluid.…”

Section: State Of the Artmentioning

confidence: 99%

Solid-Liquid Flow of Axial Flow Pump in Loop Reactor and Operating Control with Single Invert

Yan¹,

Wang²,

Shi³

et al. 2019

Int. j. simul. model.

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Solid concentration changes may affect the solid-liquid flow of the axial flow pump in the polypropylene loop reactor, accompanied with unstable operations (e.g., axial power fluctuation). The influencing factors and formation mechanisms of axial power fluctuation were analysed. After that, to discuss the influences of energy allowance of the mixture media in the loop reactor, the internal flow status of the pump under different solid volume fractions were compared. Then a head-correction strategy of operating control with single invert was proposed, to smooth the axial power fluctuation of the axial flow pump. Results demonstrate that viscosity of the mixture media is positively related, whereas the head of the axial flow pump is negatively correlated with solid concentration. Besides, head-correction curves can effectively regulate the off-design operation of pump under different solid volume fractions, with the energy allowance and the axial power fluctuation reduced in the loop reactor and the pump. Researches provide important references for the analysis of internal flow status and the solution of axial power fluctuation of the axial flow pump in the polypropylene loop reactor.

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Simulation and Analysis of Two-Core Asymmetric Phase Shifting Transformer Combined Loop Power Supply Control Based on Voltage Four-Quadrant Analysis

Li,

Yang,

et al. 2024

Lecture Notes in Electrical Engineering

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CFD investigations of particle segregation and dispersion mechanisms inside a polyolefin 8-leg loop reactor of industrial scale

Cited by 11 publications

References 14 publications

Optimal Design of Bypass Line for an Industrial-Scale 8-Leg Polyolefin Loop Reactor to Manage Slurry Dispersion Using Hydraulic and CFD Simulations

Optimal Design of Bypass Line for an Industrial-Scale 8-Leg Polyolefin Loop Reactor to Manage Slurry Dispersion Using Hydraulic and CFD Simulations

Solid-Liquid Flow of Axial Flow Pump in Loop Reactor and Operating Control with Single Invert

Simulation and Analysis of Two-Core Asymmetric Phase Shifting Transformer Combined Loop Power Supply Control Based on Voltage Four-Quadrant Analysis

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