Hyperlene A LDPE and EVA Technology

Lummus Technology’s Hyperlene™ A low-density polyethylene (LDPE) and ethylene-vinyl acetate (EVA) technology uses a high-pressure double-autoclave reactor technology developed by Sumitomo Chemical Corporation. The unique reactors operate in concert with an intermediate cooling step to maximize the monomer conversion and produce high-quality LDPE — including premium extrusion coating film grades — and premium EVA and High EVA (HEVA) grades, with up to 40% vinyl acetate (VA) content.

Features and Benefits

Competitive CAPEX

• High-conversion process minimizes investment in high-pressure ethylene recycle system
• World-scale capacity up to 200 kta

Low OPEX

• High-conversion process minimizes energy and cooling water consumption for recompression and cooling of recovered monomer
• Low net monomer consumption through effective monomer recovery
• Low energy consumption translates to low equivalent CO2 emissions

Excellent operability and reliability

• Reliable process with excellent reactor control
• Low occurrence of decomposition reaction through design and operational excellence
• Longer run times between process cleaning steps

Superior product quality

• Optimized long-chain and short-chain branching molecular structure
• High VA content (up to 40%)
• Broad product range (MFR, density, VA content)

Additional Advantages

• Strong safety track record
• Short and easy turn-around maintenance
• Integration opportunities with Lummus Technology’s upstream monomer technologies

Simplified Block Flow Diagram

The Process

Ethylene is compressed from battery limit conditions to intermediate pressure. It is mixed with recycled monomer and (when producing EVA) vinyl acetate as comonomer. The monomer is then further compressed to operating pressure (1,200 – 2,000 barg) in a secondary compressor. The monomer mix is cooled and fed to the first autoclave reactor in multiple positions and a reaction initiator (typically, an organic peroxide) is injected into the reactor at various positions to initiate the radical polymerization reaction to form polyethylene (LDPE or EVA). A chain transfer agent is applied to control the molecular weight.

The reaction is exothermic and the reactor operates adiabatically. After the first reactor, the monomer/polymer mixture is cooled down before it enters a second autoclave reactor along with the monomer and initiator to maximize the conversion of the monomer.

The monomer/polymer mixture then is reduced in pressure to intermediate level and enters the high-pressure separator where the majority of monomer is recovered and returned to the inlet of the secondary compressor. The polyethylene flows in molten condition and with a further pressure reduction into the low-pressure separator, before entering the extruder.

After the extruder, there are blending and pellet devolatilization silos. EVA products have a sticky nature and will undergo special handling in these sections.