Vinyl Ester Separation from Ethylene Gas via Staged Cooling

The patent applies parameter changes by progressively cooling the gas stream through multiple heat exchangers at different temperature stages. The first heat exchanger cools to a first temperature to condense high-boiling esters, while the second heat exchanger cools to a lower second temperature to condense remaining esters. This staged temperature reduction optimizes separation efficiency while managing energy consumption more effectively than single-stage cooling.

The cooling and separation process is segmented into multiple stages. The gas stream is divided and processed through separate heat exchangers and separation vessels at different temperature levels. This segmentation allows different esters with varying boiling points to be condensed and separated at appropriate temperature stages, improving overall separation efficiency without requiring excessive cooling energy for the entire stream at once.

The separation system is segmented into multiple functional units: a first heat exchanger for initial cooling, a first separation vessel for high-boiling ester removal, a second heat exchanger for further cooling, and a second separation vessel for remaining ester removal. Each segment performs a specific separation task, achieving high purity through cumulative effect while keeping each individual unit relatively simple and standardized.

The first heat exchanger and first separation vessel perform preliminary cooling and separation of high-boiling esters before the gas stream enters the second heat exchanger. This preliminary action removes the most difficult-to-separate components first, reducing the burden on subsequent separation stages and improving overall efficiency without requiring all components to operate at maximum capacity simultaneously.

The patent extracts esters of vinyl alcohol from the gas stream through condensation and separation in dedicated vessels. By removing these esters before the gas stream is recycled to the polymerization reactor, the source of corrosive by-products is eliminated. This extraction prevents the formation of corrosive degradation products that would otherwise accumulate and compromise equipment integrity.

The separation process acts in advance to remove esters of vinyl alcohol before they can decompose into corrosive by-products during recycling. This preliminary anti-action prevents the harmful effect of corrosion before it can occur, protecting the polymerization reactor and associated equipment from damage while maintaining process simplicity through preventive rather than remedial measures.