Polyethylene

Polyethylene

Abstract

Fluor has implemented the following systems: assorted monomer treatment and recovery units; a myriad of polymer separation and product degassing and/or drying schemes; various solvent/carrier/diluent recovery systems; and a wide range of polymer handling facilities, finishing lines, compounding lines and packaging lines. The projects executed by Fluor have ranged from technology screenings and process studies to expansions, revamps, modernizations and debottlenecking projects to integrated grass-root plant facilities.

Client Benefits

Throughout Fluor's involvement in the polyolefin industry, the company has provided engineering solutions and innovative designs to Clients emphasizing cost, efficiency, safety, reliability and operability.

Broad polymer experience has given us the opportunity to solve the many problems that can arise in conveying crumb, powder, flake and/or pelletized product. Pneumatic systems can be designed utilizing air or an inert gas (such as nitrogen) and can be either open loop (once through) or closed loop (recirculating). Through Fluor's experience in producing reliable product conveying systems, Fluor is in a position to offer recommendations for an optimum solids handling system tailored to the specific requirements and needs of the Client.

Related Technologies

Monomer and Other Feedstock Production and Handling
Fluor's design experience encompasses the facilities to manufacture, store, meter, monitor, transfer, blend, and inject the numerous monomers and other compounds used in polyolefin production. Many of the feedstocks and monomers require some pretreatment, such as dehydration, to remove impurities and process poisons. Fluor has designed drying systems and other trace component removal systems required for monomer and feedstock pretreatment.

Catalyst Production and Handling
Fluor projects have involved the use of a variety of catalysts and catalyst aiding compounds including Ziegler-type titanium and chromium catalysts, and metal alkyls. These compounds have been handled as slurries, liquid streams, and solid feeds. The project facilities have ranged from catalyst production units to the handling, mixing, and injection of catalyst feeds. Fluor has been involved in the study of the impact of new catalysts, such as metallocenes, in existing plant facilities. Fluor has also dealt with a variety of catalyst ""kill"" agents, which are used both in normal operation and emergency situations.

Reactor Systems
Fluor's qualifications in polymerization process design include tubular, autoclave (stirred, jacketed vessels, which may have special surface materials or complex internals), circulating loop, and fluidized bed reactors. The processes have included slurry and gas phase technologies. The polymerization units have been in continuous, batch and semi-batch operation. Several projects have involved using two or more reactors in series.

Polymer Separation and Drying or Degassing
The requirements for polymer separation and drying or degassing depend on the polymerization technology employed. Fluor has experience that includes the removal of unreacted monomers, solvents or carriers, and low molecular weight polymer byproducts. Fluor has utilized a variety of mechanical separators and dryers (centrifuges, rotary dryers, fluidized bed dryers, etc.), purge columns, depressurization, process flash, and other evaporative techniques.

Monomer, Solvent/Carrier and Hydrocarbon Recovery
Fluor has broad experience in recovery of monomers and solvent or carrier hydrocarbons for recycle to the process feed. The design schemes usually utilize one or more fractionation columns to separate the various compounds including unreacted monomers, the solvent or carrier hydrocarbon, and low molecular weight polymerization byproducts. The overall plant efficiency, plant economics, and product quality can be impacted by the proper selection of the process scheme and requirements of the recovery unit.

Polymer Compounding, Finishing and Packaging
Fluor has engineered, procured and constructed the ""dry end"" (additive systems, blending, compounding, extruding, pelletizing or rolling, conveying, bagging, and related operations) of polyolefin plants. This experience covers additive storage, handling, metering, mixing and injection systems; raw polymer (as crumb, powder, and flake) storage, blending, conveying and metering; use of hot melt extruders, homogenizing extruders and extruders handling powders; use of film and blown product production equipment; pelletizing; pellet product storage, blending and conveying; and product packaging including bagging and rolls.