In-line blending process

Abstract

An in-line blending process for polymers comprising: (a) providing two or more reactor-low pressure separator units (1, 7) in parallel configuration, each reactor-low pressure separator unit comprising one reactor (2, 8) fluidly connected to one low pressure separator (3, 9) downstream and further a recycling line (5, 11) connecting the low pressure separator (3, 9) back to the corresponding reactor (2, 8); (b) polymerizing olefin monomers having two or more carbon atoms in each of the reactors (2, 8) in solution polymerisation; (c) forming an unreduced reactor effluents stream including a homogenous fluid phase polymer-monomer-solvent mixture in each of the reactors (2, 8), (d) passing the unreduced reactor effluents streams from each of the reactors (2, 8) through the corresponding low pressure separators (3, 9), whereby the temperature and pressure of the low pressure separators (3, 9) is adjusted such that a liquid phase and a vapour phase are obtained, whereby yielding a polymer-enriched liquid phase and a polymer-lean vapour phase, and (e) separating the polymer-lean vapour phase from the polymer-enriched liquid phase in each of the low-pressure separators (3, 9) to form separated polymer-lean vapour streams and separated polymer-enriched liquid streams; (f) combining the polymer-enriched liquid streams from step (e) in a further low-pressure separator and / or a mixer (13)to produce a combined polymer-enriched liquid stream (16); (g) reintroducing the polymer-lean vapour streams from step (e) via recycling lines (5, 11) into the corresponding reactors (2, 8).

Description

technical field

[0001] The present invention relates to an in-line blending process of two reactors operating in a parallel configuration for the production of polymers. Background technique

[0002] In traditional polymer production, reactors are operated in series. This operation allows the use of different process conditions and thus the properties of the polymer produced in a single reactor can be varied. Within certain limits it is possible, for example, to vary the molecular weight distribution of the total feed, ie the feed produced in all reactors. However, a separate polymerization of the polymer independent of the further steps is also desirable, since there are more possibilities for adjusting the microstructure when there is no need to take into account the second or third step. For example, if bimodal polyolefins are to be produced, the material transferred from one reactor to the other remains active, i.e. the remaining catalyst activity will determine the ch...

Images