Patent EA-002084-B1 (EA)
Title: Process for polymerisation of olefins and atomizing nozzle therefor
Inventor: NEWTON DAVID
IPC: C08F10/00
Filed: 1997-10-22
Abstract: 1. A continuous gas fluidised bed process for the polymerisation of olefin monomer selected from (a) ethylene, (b) propylene, (c) mixtures of ethylene and propylene and (d) one or more other alpha-olefins mixed with (a), (b) or (c), in a fluidised bed reactor by continuously recycling a gaseous stream comprising at least some of the ethylene and/or propylene through a fluidised bed in said reactor in the presence of a polymerisation catalyst under reactive conditions, at least part of the said gaseous stream withdrawn from said reactor being cooled to a temperature at which liquid condenses out, separating at least part of the condensed liquid from the gaseous stream and introducing at least part of the separated liquid directly into the fluidised bed by: (a) pressurising the liquid; (b) feeding the pressurised liquid to a liquid inlet of a nozzle; and (c) discharging the liquid into the fluidised bed through an outlet of the nozzle in which the liquid is atomised using a mechanical device positioned within the outlet and an atomised spray is formed within a spray-forming zone of the outlet. 2. A process as claimed in claim 1 wherein the spray-forming zone of the outlet is located within the nozzle. 3. A process as claimed in one of claims 1 or 2 wherein the atomised liquid spray is injected into the bed in a substantially horizontal direction. 4. A process as claimed in one of claims 1 to 3 wherein the small amount of gas in the range 0.5 to 10 percent by weight, based on the total weight of gas and liquid passing through the nozzle, is introduced into the liquid before the liquid passes through the mechanical device. 5. A process as claimed in one of claims 1 to 4 wherein the catalyst is an activated transition metal based metallocene catalyst. 6. A process as claimed in one of claims 1 to 5 wherein the fluidised bed reactor is provided with a plurality of nozzles. 7. A process for the injection of liquid into a fluidised bed which comprises: (a) pressurising the liquid; (b) feeding the pressurised liquid to a liquid inlet of a nozzle; and (c) discharging the liquid into the fluidised bed through an outlet of the nozzle in which the liquid is atomised using a mechanical device positioned within the outlet and an atoinised spray is formed within a spray-forming zone of the outlet. 8. A nozzle suitable for use as claimed in claim 1 for the injection of liquid into a fluidised bed said nozzle comprising:( a) a pressurised liquid inlet; and  (b) a liquid outlet in which a mechanical device is provided within the liquid outlet to atomise the liquid and the liquid outlet is provided with a spray-forming zone.  9. A nozzle as claimed in claim 8 wherein the spray-forming zone is defined by a wall which is an integral part of the nozzle, or which protrudes from the nozzle, or which is secured in spatial relationship to the nozzle. 10. A nozzle as claimed in claim 9 wherein the wall defining the spray-forming zone comprises a tube or a plate. 11. A nozzle as claimed in one of claims 8 to 10 wherein the nozzle is positioned within the fluidised bed and has 2 to 4 outlets. 12. A nozzle as claimed in one of claims 8 to 11 wherein the outlet is a slot having an elliptical shape. 13. A nozzle as claimed in one of claims 8 to 12 wherein the nozzle has a series of outlets arranged in groups circumferentially around the nozzle. 14. A nozzle as claimed in claim 13 wherein the groups of outlets are arranged in a number of rows around the circumference of the nozzle. 15. A nozzle as claimed in one of claims 13 or 14 wherein each group of outlets is connected separately to a supply of pressurised liquid. 16. A nozzle as claimed in one of claims 8 to 15 wherein the nozzle has a liquid flux rate in the range 9.5 to 70 m<3> liquid/s/m<2> outlet cross-sectional area wherein the nozzle liquid flux rate is defined as the volumetric flow rate of liquid (m<3> /s) per unit cross-sectional area (m<2>) of the nozzle outlets.