Polymerisation unit and polymerisation process

Polymerisation unit for ionic polymerisation of a liquid monomer(s) containing reaction mixture, comprising a polymerisation loop and a coolant loop and a heat exchanger reactor system (“HERS”) which is shared amongst the polymerisation loop and the coolant loop, wherein

• the polymerisation loop comprises a reaction mixture piping system connected to an inlet and an outlet of said HERS,
• the coolant loop comprises a coolant piping system connected to an inlet and an outlet of said HERS,
• the reaction mixture piping system comprises a circulating pump and the polymerisation loop comprises a polymer withdrawal system, characterised in that
• 1) the HERS comprises at least “x” parallel sections wherein a section shares its last coolant passage with the first coolant passage of the next section,
• 2) the said HERS' sections comprise “n” parallelepipedic channel(s) for the reaction mixture, “n” being an integer comprised between 2 and 20, and “n+1” passages for the coolant,
• 3) the flow paths of the reaction mixture in the “n” channel(s) of a section are unidirectionally parallel,
• 4) the flow paths of the coolant in the “n+1” passages of a section are unidirectionally parallel to the reaction mixture flow paths, and
• 5) the coolant is not in direct contact with the reaction mixture,
• 6) and wherein the dimensions of the reaction mixture parallelepipedic channels are characterised by
• a. a first dimension (“height”) comprised between 2 and 10 m,
• b. a second dimension (“depth”) comprised between 0.1 and 3 m, and
• c. a third dimension (“width”) comprised between 2 and 50 mm.