Process for deodorization of recycled polyolefin pellets
AssigneeAlpla Werke Alwin Lehner GmbH & Co. KG
InventorsRobert Siegl, Michael Heyde
Life of this patent
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Abstract
Process for deodorization of recycled polyolefin pellets (23) in three steps: In a first step, the moist pellets (23) are contacted with a circulating inert gas at a temperature between 110° C. and 160° C. in a steam stripper (11), and the steam is precipitated in a condensate trap (29). In a second step, the pellets (23) are sent to a vacuum silo (13) under negative pressure and contacted with a gas flowing in countercurrent. In a third step, after the vacuum silo (13) the pellets (23) are sent to a first heat exchanger (15) and contacted with the gas flowing in countercurrent from the second step.
Claims17
A process for deodorization of recycled polyolefin pellets extruded from used recyclable polyolefin flakes, the recycled polyolefin pellets that are still odorous being formed in an underwater pelletizer or water ring pelletizer,
- comprising:
- in a first step, contacting recycled polyolefin pellets in a moist state with a circulating inert gas in a steam stripper, wherein steam is precipitated in a condensate trap, by which odor components adhering to surfaces of the recycled polyolefin pellets are removed, and the recycled polyolefin pellets are preheated;
- in a second step, sending the recycled polyolefin pellets to a vacuum silo under a negative pressure and contacting the recycled polyolefin pellets with a gas flowing in a countercurrent, wherein odor components that have penetrated into the recycled polyolefin pellets are removed by the negative pressure and a surface temperature of the recycled polyolefin pellets remains below 123° C. for more than 10 hours, and
- in a third step, after the vacuum silo, sending the recycled polyolefin pellets to a first heat exchanger and contacting the recycled polyolefin pellets with the gas flowing in the countercurrent from the second step, by which the recycled polyolefin pellets are cooled and the gas is preheated for the second step.
Dependencies are inferred from the claim text.