LDPE copolymers ethylene-vinylacetate copolymer EVA

Because of the high concentration of vinylacetate (VA) required in the process gas to produce the required products, the EVA copolymers are of particular interest for the emissions to the air. 

The EVA copolymers are generally produced in high pressure lines of smaller capacities, typically between about 20 - 100 kilotonnes per year, to supply the more fragmented and smaller market sizes compared to the LDPE homopolymers. 

The power and monomer consumption are higher compared to the figures for LDPE homopolymers because of limitations to the maximum conversion to polymer and the limit to the temperatures which can be used in the copolymerisation process. The other performance data for EVA copolymers production and the streams for water, waste water and solid waste are similar to the ones for the homopolymer process. Table 3.10 shows emission and consumption data per tonne of EVA copolymer. 

The emission and consumption data shown in Table 3.11 represent the emission and consumption levels of 24 plants that reported their data. The average age of these plants is 15 years and their average capacity in 1999 was 161 kt per year. 

The data given in Table 3.11 do not take into account the different properties of the product, such as bimodal polyethylene or high molecular weight polymers, which can lead to a strong deviation in energy and water consumption. 

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