Focus on LDPE-LLDPE-HDPE process

  • Polyethylene (PE) is one of the most used plastic in the world, and concerns a countless industries, segments and applications.

LLDPE linear low density polyethylene productPE allows packing alimentary goods in an economic way while extending their lifetime, transporting and distributing chemicals products safely, routing potable water to populations, protecting new cars’ body against scratches, and other useful applications in daily life. The principal proprieties of polyethylene are to be hermetic, easy to treat, low cost and guarantee a good chemical resistance.

Polyethylene (PE) is characterized by an important number of families and proprieties which allow using it in extremely various applications, there are among other:

–    LDPE – low density polyethylene, use in alimentary industry or pharmacology.
–    HDPE – high density polyethylene
–    MDPE – medium density polyethylene
–    LLDPE butene C4 – linear low-density polyethylene, used in extrusion, frozen goods, cling film, cosmetic and pharmaceutical tubes

  • Manufacturing  process of LDPE

The production process of LDPE is cut in five operations:

–    The gas compression: after the ethylene supply, it is squeezed in the 1st compressor with a gas from the process and which has not react. This first squeezed gas is remixed with gas which has not reacted and pass through the second compressor
–    The polymerization: an initiator/activator (organic peroxide) is added to this second squeezed gas in the reactor; the mixture is obtained using a stirrer. The polymerization is obtained under particular temperature and pressure conditions.
–    The separation of the gas: the gas that has not reacted is then separated after the passing in 3 distinct separators. These safe gases are reinjected upstream the two compressors, to be note that a part will be excluded of the process.
–    The extrusion: once the non-reacted gas is removed, the polymers can be extruded in form of granules.
–    The storage and packaging/conditioning: the granules are dry and stocked according to their granulometry. The gassing is made by warm air injection.

  • Recommended valves for the LDPE, HDPE,LLDPE production :

custom made piston valve guichon_655N for LLDPE HPDE LDPE process_DN100x100GUICHON VALVES proposes special valves for the production of polyethylene especially adapted to viscous liquids and conceived to minimize the load loss and dead zones.
The valves double jackets allow maintaining the fluid at temperature to avoid the solidification of the polyethylene. The air tightness materials (packing, gaskets …) are selected in order to avoid the pollution of the polyethylene.
GUICHON also proposes valves especially designed to answer to the abrasion problem meet during the flow of powder and granules.