| 摘要 |
In a process for preparing polyethylene in tube reactors with or without autoclaves, where a free-radical initiator is introduced with or without cold ethylene into a flowing ethylene- and comonomer-containing medium, rotation is generated between two streams ( 61, 62 ) to be mixed at an angle ( 66 ) or by provision of a swirl element ( 20, 80 ) in the flow cross section ( 27, 28 ). In the region of a feed point ( 72, 81 ) for a free-radical initiator, there is provided a cross-sectional constriction ( 63, 67, 71 ) at which the free-radical initiator is introduced through an optimized off-center outlet opening ( 44 ) of an introduction finger ( 40 ) into the rotating flow ( 61, 62, 70 ).
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