Process for the work-up of used plastics or mixtures of used plastics for use in refineries

摘要

Used plastics were to be worked up in such a way that products containing no functional groups are obtained which can be mixed into the petroleum intermediates in an improved manner in the bypass in refineries without separation phenomena. The used plastics or mixtures of used plastics are degraded in an extruder under shear forces and at elevated temperature, a progressive temperature profile up to 475 DEG C being set up to 2/3 of the effective extruder lengths and subsequently a degressive temperature profile being set in the remaining 1/3 of effective extruder length, so that the temperatures at the extruder end are between 280 and 380 DEG C. From 10 to 50% by weight of an asphalt-free petroleum product are metered in there, and homogenisation in a static mixer having /= 4 baffles is carried out. The procedure can be carried out internally directly in a refinery or externally, in which case granules are produced which are metered into the refinery plant feed stream via a melting and metering unit. The products obtained are easier to handle, and the number of operational interruptions is significantly reduced through the use of used plastics.