In the process flow sheet (Figure 3

In the process flow sheet (Figure 39.1), is the description of Low Pressure Ziegler Process to produce polyethylene.

At the very onset, through the process of desulphurization and removal of light ends, high purity ethylene is prepared.
The ethylene is further treated to remove traces of oxygen and its compounds which can possibly deactivate the catalyst.

The ethylene is first pumped into a reactor where it is mixed with catalyst diluents stream.
The optimum temperature and pressure maintained should be 70°C and 7 atms gage. The effluent stream then follows across a series of flash drums inorder to remove the solvent from the catalyst.
The residual catalyst at this point is removed by adding water.
The flashed solvent is thereafter recycled to the catalyst make –up unit after appropriate drying and redistillation.
The slurry which results is then centrifuged to remove the water, and the water is treated to remove the catalyst before recycle.
The final products of polyethylene solids are then dried, extruded and given the required final forms.