Computational fluid dynamics and electrostatic modeling of
The multi-fluid CFD model [51] solves the mass and momentum balances of gas and solid phase (Table 1).The gas phase equations are derived by ensemble averaging the local instantaneous balance equations [56], [57], [58] over a control volume larger than the characteristic volume of the solid phase. The model is based on the …
اقرأ أكثر
Electrostatics and Gas Phase Fluidized Bed
Reduction of electrostatic charge accumulation in fluidized bed polymerization reactors can reduce the frequency of reactor wall sheeting incidents and …
اقرأ أكثر
Substrate-Free Gas-Phase Synthesis of Graphene …
We present a novel method for synthesizing graphene sheets in the gas phase using a substrate-free, atmospheric-pressure microwave plasma reactor. Graphene sheets were …
اقرأ أكثر
Rhetorical synthesis: medium (practice) | Khan Academy
Rhetorical synthesis: medium. While researching a topic, a student has taken the following notes: Muslins are woven cotton fabrics with a variety of uses. Dhaka muslin is a handmade fabric produced in Dhaka, Bangladesh. It has an extremely fine weave and is primarily used to make luxury clothing. Sheeting muslin is a machine-made fabric ...
اقرأ أكثر
Method for preventing fouling and sheeting in gas phase …
The invention concerns a method for preventing fouling and sheeting in polymerization reactors, particularly in gas phase reactors of multiphase polymerization processes. Various methods for manufacturing solid polymers from hydrocarbons, for example from 1-olefins have been developed. In one such method olefins, such as …
اقرأ أكثر
Electrostatics and gas phase fluidized bed
Semantic Scholar extracted view of "Electrostatics and gas phase fluidized bed polymerization reactor wall sheeting" by Gregory G. Hendrickson. Skip to search form Skip to main content Skip to account menu. Semantic Scholar's Logo. Search 215,151,346 papers from all fields of science. Search ...
اقرأ أكثر
Electrostatics and gas phase fluidized bed
Section snippets Sheeting characterization. In deep fluidized beds wall sheet formation typically occurs near an elevation from 1 / 4 to 3 / 4 of the reactor diameter above the fluidization gas distributor plate as illustrated in Fig. 1. The bed circulation near the wall changes from generally upward at lower elevations to generally downward at higher …
اقرأ أكثر
Hydrodynamics of Fluidization with Surface Charge
Chapter. Hydrodynamics of Fluidization with Surface Charge. Hamid Arastoopour, Dimitri Gidaspow & Robert W. Lyczkowski. Chapter. First Online: 22 August …
اقرأ أكثر
Progress in study of electrostatics and wall sheeting in gas phase
Some research works on electrostatics and wall sheeting in gas phase polymerization fluidized bed reactor were reviewed, including description of reactor wall sheeting, relationship of ...
اقرأ أكثر
Electrostatics and gas phase fluidized bed polymerization …
The multi-phase CFD model for gas–solid flow is based on the kinetic theory of granular flows and the frictional theory. The electrostatic model is developed based on a fixed, size-dependent charge for each type of particle (catalyst, polymer fines and polymer). ... a process for reducing sheeting during production of polyolefins by ...
اقرأ أكثر
Covers for manure storage
Covers reduce the effect of wind blowing across the surface of a manure storage facility. Higher wind increases the rate that gas molecules push away from the manure surface, increasing the potential. Covers also can reduce wave action or rippling at the manure surface. Waves and ripples can decrease the resistance of naturally forming films or ...
اقرأ أكثر
Effect of fluidizing particle size on electrostatic
The fluidizing particles utilized in this study were polyethylene resin produced using a metallocene based catalyst in an industrial gas-phase fluidized bed reactor. The resin had a particle density of 918 kg/m 3 and a wide size distribution, ranging approximately from 20 to 1500 μm. To study the effect of only particle size, this resin was ...
اقرأ أكثر
AU706943B2
Date Oct. 17, 1996A method for preventing sheeting problems in a gas phase reactor in such multi-phase polymerization process, which comprises at least one loop reactor followed by a gas phase reactor, where the polymerization is continued in the presence of added monomers, and in which process a fouling preventive agent is used to prevent ...
اقرأ أكثر
Optimization of Energy Consumption in Gas-Phase
Gas-phase polymerization is a method that is widely used in the polymer production process. The heterogeneous reaction between monomer gas and solid catalyst takes place in the fluidized bed reactor to produce the polymer product. The design and production planning of this process is a difficult task due to the complicated fluid behavior …
اقرأ أكثر
Designing wet duct/stack systems for coal-fired plants
The problem of SLD from a duct and stack system operating in "all-scrubbed" mode is exacerbated by the two-phase flow interaction of liquid and gas. The liquid enters the ducts and stack as ...
اقرأ أكثر
Analysis of wall fouling and electrostatic charging in gas-solid
Wall sheeting and electrostatic charging in gas–solid fluidized beds were studied. ... The results showed that the distribution of the solid phase depended on the charge and polarity of the particles. When the charge density of particles exceeded a critical level, the particles adhered to the wall and caused wall fouling or wall sheeting. ...
اقرأ أكثر
METHOD FOR PREVENTING FOULING AND SHEETING IN GAS PHASE …
A method for preventing sheeting problems in a gas phase reactor in a multi-phase polymerization process which comprises one or more loop reactors, where alphaolefins are polymerized or copolymerized in particle form in the presence of catalysts and which loop reactor(s) is/are followed by a gas phase reactor, where the polymerization is ...
اقرأ أكثر
Polyethylene (PE) Technologies | LyondellBasell
Lupotech Processes - LDPE and EVA. Lupotech is the market leader on high-pressure technology.Lupotech T, with its high conversion rates and effective heat recovery system, offers the lowest operating and investment costs.Lupotech A combines the strengths of Lupotech T with an autoclave vessel to provide EVA – copolymers with up to …
اقرأ أكثر
Electrostatics and Gas Phase Fluidized Bed
Download Citation | Electrostatics and Gas Phase Fluidized Bed Polymerization Reactor Wall Sheeting | Reduction of electrostatic charge accumulation in fluidized bed polymerization reactors can ...
اقرأ أكثر
US6096837A
A method for preventing sheeting problems in a gas phase reactor in such multi-phase polymerization process, which comprises at least one loop reactor followed by a gas phase reactor, where the polymerization is continued in the presence of added monomers, and in which process a fouling preventive agent is used to prevent fouling or sheeting in the …
اقرأ أكثر
CFD Modeling of Electrostatic Forces in Gas-Solid Fluidized …
Electrostatic charges in gas-solid fluidized beds are known to influence the bed dynamics, bubble shape and size, particle agglomeration, segregation and entrainment. ... Electrostatics and gas phase fluidized bed polymerization reactor wall sheeting, Chemical Engineering Science, 2006, 61, 1041–1064.
اقرأ أكثر
Ethylene Polymerization Processes and Manufacture of …
Abstract This chapter contains sections titled: Introduction Processes Resin Property and Reactor Control in Catalytic Polymerization Reactors Economics
اقرأ أكثر
An overview of advances in understanding electrostatic
There are various types of catalyst that have been used for gas-phase polyethylene reactions, for example, Ziegler−Natta catalysts, chromium based catalysts, and single site catalysts such as metallocene catalysts [133]. The catalyst is typically injected into the reactor in the reaction zone through pneumatic conveying using narrow stainless ...
اقرأ أكثر
A perspective on electrostatics in gas-solid fluidized
Hendrickson [1] reviewed electrostatics phenomena in gas phase polymerization fluidized bed reactors, with a focus on commercial issues, particularly wall sheeting, and mitigation techniques. Basic concepts of contact charging and charge transfer, as well as powder charging mechanisms, were reviewed by Matsusaka et al. [ 19 ].
اقرأ أكثر
Effects of external DC/AC electric fields on particle motions …
Hendrickson G. Electrostatics and gas phase fluidized bed polymerization reactor wall sheeting[J]. Chemical Engineering Science, 2006, 61(4): 1041-1064. 10: Yamaguchi Y, Suga S, Morikawa M, et al. Method for producing polyolefin:US5525687 [P]. 1995. 11: Park A H, Bi H, Grace J R. Reduction of electrostatic charges in gas-solid …
اقرأ أكثر
WO2005068507A1
Method for controlling sheeting in gas phase reactors Download PDF Info Publication number WO2005068507A1. WO2005068507A1 PCT/US2004/041988 US2004041988W WO2005068507A1 WO 2005068507 A1 WO2005068507 A1 WO 2005068507A1 US 2004041988 W US2004041988 W US 2004041988W WO …
اقرأ أكثر
Computational and experimental study of electrostatics in gas…
The gas-phase processes are more advantageous and use fluidized-bed reactors for commercial production of polyethylene. Although gas-phase processes have advantages, there are some disadvantages like particle agglomeration and sheeting. These disadvantages are due to electrostatics and hot spot formation (Hendrickson, 2006). …
اقرأ أكثر
PE Gas Phase
Grace's polyethylene catalysts have consistently produced film, blow molding, and pipe grades using the gas phase processes for decades. Additionally, our technical …
اقرأ أكثر
EP0820474B1
Date Oct. 17, 1996A method for preventing sheeting problems in a gas phase reactor in such multi-phase polymerization process, which comprises at least one loop reactor followed by a gas phase reactor, where the polymerization is continued in the presence of added monomers, and in which process a fouling preventive agent is used to prevent ...
اقرأ أكثر
Method for controlling sheeting in gas phase reactors
Embodiments of the present invention relate to measuring and controlling static in a gas phase reactor polymerization. In particular, embodiments relate to monitoring carryover static in an entrainment zone during gas phase polymerization to determine the onset of reactor discontinuity events such as chunking and sheeting. Embodiments also …
اقرأ أكثر