Technology Type

The high-pressure LDPE (Low Density Polyethylene) process is very generic and the basic design does not change from company to company. The major variation is in reactor type, tubular versus autoclave. The choice between tubular or autoclave reactor is mainly dictated by the desired product.

In principle, the tubular process is preferred to make resins with good optical properties, while only the autoclave process can make good extrusion coating resins and more homogeneous copolymer products. General purpose products can be manufactured from both technologies.

The ethylene conversion level achieved in the tubular process is typically higher than for the autoclave process, however, due to the typical lower operating pressure level in the autoclave process, the final energy consumption per tonne polyethylene produced can be the same for both processes.

Source: European Commission, European IPPC Bureau, Aug 2007, Reference Document on Best Available Techniques in the Production of Polymers.