MULTI-REACTOR AND MULTI-ZONE POLYOLEFIN POLYMERISATION Russian patent published in 2022 - IPC B01J19/24 B01J8/18 C08F10/02 

FIELD: polymers.

SUBSTANCE: invention relates to a group of inventions; namely, to variants of an apparatus for producing multimodal polyethylene. Apparatus for producing multimodal polyethylene comprises: a first reactor configured to produce a first polyethylene; a second reactor configured to produce a second polyethylene and a third polyethylene, wherein the second reactor comprises: a riser pipe configured to produce the second polyethylene; an upper pipeline with an end in fluid communication with the upper part of the riser pipe; a separator in fluid communication with the opposite end of the upper pipeline; a discharge pipe configured to produce the third polyethylene, wherein the upper part of the discharge pipe is in fluid communication with the separator through a liquid barrier in the upper part of the discharge pipe; a heating apparatus configured to add or remove heat from the discharge pipe; and a lower pipeline with an end in fluid communication with the lower part of the discharge pipe and an opposite end in fluid communication with the lower part of the riser pipe. The second reactor is configured to receive the first polyethylene from the first reactor, or the first reactor is configured to receive the second polyethylene and the third polyethylene from the second reactor. The second reactor has an internal surface polished to a root mean square value of less than approx. 150 microinches.

EFFECT: production of multimodal polyolefins with improved values of stiffness and Young's modulus of elasticity, secant modulus of resistance and/or modulus of bending elasticity, lowering the weight of moulded pipes.

20 cl, 27 dwg