Patent application number | Description | Published |
20110009576 | POLYMERISATION PROCESS - The present invention relates to a polymerisation process and in particular to a process for the copolymerisation of ethylene and an α-olefin comonomer having 7 to 10 carbon atoms in a fluidised bed gas phase reactor in the presence of a multi-site Ziegler-Natta polymerisation catalyst characterised in that (i) said process is operated in condensed mode, (ii) the amount of said α-olefin is maintained below that at which substantial condensation in the reactor occurs and (iii) at least one of the following apply: | 01-13-2011 |
20110152477 | METHOD FOR THE PRODUCTION OF POLYMERS - The present invention relates to methods useful for the production of polymer powder, and in particular to a method for transitioning from a first process for production of a first polymer to a second process for the production of a second polymer during a polymerisation campaign in a polymerisation apparatus, said polymerisation apparatus comprising a reaction vessel and a degassing vessel, in which the respective first and second processes each comprise: (a) bringing a principal olefin and a comonomer into contact with a catalyst under gas phase polymerisation conditions in the reaction vessel to form the respective first or second polymer, wherein said first and second process utilise the same principal olefin but differ in at least one of (i) the comonomer used and (ii) the reaction temperature at which the polymer is produced, and (b) subsequently contacting the respective first or second polymer with a purge gas in the degassing vessel to remove unreacted monomers, characterised in that the method for transitioning comprises changing the flow rate of purge gas in the degassing vessel from a first rate, X | 06-23-2011 |
20110152484 | METHOD FOR CONTROLLING A PROCESS FOR POLYMERISATION OF AN OLEFIN - The present invention relates to a method for controlling a process for polymerisation of an olefin, and in particular to a method for controlling a process for polymerising at least one olefin in a reaction zone, said process comprising in the reaction zone a reaction mixture and polymer particles, the reaction mixture comprising a principal olefin and at least one further reagent, and wherein the process is controlled using the ratio of at least one further reagent to principal olefin in the polymer particles in the reaction zone or in the amorphous phase of said polymer particles. | 06-23-2011 |
20110160420 | PROCESS FOR THE DEGASSING OF POLYMER POWER - The present invention provides a process for the production of a degassed polymer powder, which process comprises a) feeding i) a principal monomer, and ii) one or more comonomers fed in an amount of at least 5000 ppmw relative to the principal monomer feed rate, and iii) optionally one or more added alkanes having 2 to 10 carbon atoms, fed in an amount of at least 1000 ppmw relative to the principal monomer feed rate; into a polymerisation reactor wherein the monomer and comonomers react to form a polymer comprising residual hydrocarbons comprising one or more hydrocarbons having 3 to 10 carbon atoms, and b) passing the polymer to a degassing step wherein it is contacted with a purge gas to remove at least some of the residual hydrocarbons, characterised in that: 1) the G/P ratio in the degassing step is higher than a minimum G/P ratio, G being the purge gas mass flow rate in the degassing step and P being the polymer throughput of the degassing step, and 2) the purge gas has a concentration of critical hydrocarbon component which is lower than a maximum concentration of said critical hydrocarbon component in the purge gas, the critical hydrocarbon component being the heaviest hydrocarbon component selected from (i), (ii) and (iii) fed in step (a), which minimum G/P ratio and maximum concentration of said critical hydrocarbon component in the purge gas have been calculated based on the absorption coefficient, Kh, for the polymer powder to be degassed. | 06-30-2011 |
20120259085 | POLYMER POWDER STORAGE AND/OR TRANSPORT AND/OR DEGASSING VESSELS - The present invention relates to a polymer powder vessel, preferably a polymer powder storage and/or transport and/or degassing vessel. | 10-11-2012 |
20120289666 | PROCESS FOR THE GAS PHASE POLYMERISATION OF OLEFINS - The present invention relates to a process for the gas phase polymerisation of olefins, and, in particular, to a process for the gas phase polymerisation of olefins with recycle of fines to the reaction zone. | 11-15-2012 |
20130046070 | POLYMERIZATION PROCESS - The present invention relates to a process for the continuous transition between two different and compatible polymerisation catalysts. | 02-21-2013 |
20130053528 | POLYMERIZATON PROCESS - The present invention relates to a process for the continuous transition between two ethylene copolymers containing a different comonomer. In particular, the present invention relates to a process for the continuous transition between two ethylene copolymers containing a different comonomer. | 02-28-2013 |
20130072644 | INTERLOCK AND PROCESS - The present invention relates to production of polymer, and in particular provides an interlock for use in a process for production of a polymer in a reactor, which process comprises: a. polymerising a monomer and optionally a comonomer in the reactor to produce polymer, optionally in the presence of an inert hydrocarbon, and b. withdrawing produced polymer from the reactor, said interlock being based on the temperature in the reactor, and comprising: 1. measuring the temperature in the reactor or a temperature representative of the temperature in the reactor, and 2. comparing said measured temperature to a threshold temperature, said interlock being characterised in that withdrawal is allowed if the measured temperature is greater than the threshold temperature but is prevented if the measured temperature is lower than the threshold temperature. | 03-21-2013 |
20130072653 | INTERLOCK AND PROCESS - The present invention relates to the degassing of polymer powder, and in particular provides an interlock for use in a process for degassing of a polymer powder in a degassing vessel, which interlock comprises: a. measuring the temperature of the vapour phase resulting from a liquid-vapour separation, which vapour phase is used as a purge gas in a degassing vessel, b. comparing said measured temperature to a threshold value, and b. in the event that the measured temperature is above the threshold value then the use of the vapour as purge gas is stopped or reduced. | 03-21-2013 |
20130079476 | INTERLOCK AND PROCESS - The present invention relates to the degassing of polymer powder, and in particular to an interlock for use in a process for degassing of a polymer powder in a degassing vessel, which interlock comprises: 1. measuring the temperature of the polymer powder within or exiting the degassing vessel, 2. comparing said measurement value to a threshold value in order to ascertain whether it is lower than the threshold value or not, and 3. if the measured temperature is lower than the threshold value taking one or more actions to reduce the concentration of hydrocarbons in the polymer powder exiting the degassing vessel and/or to stop the polymer powder withdrawal from that degassing vessel. | 03-28-2013 |
20130245220 | POLYMERISATION CONTROL RPOCESS - The present invention relates to a process for maintaining a continuous gas-phase (co-) polymerisation of olefins in a large fluidised bed reactor in a homogeneous mode whilst operating at high space time yield and condensation rate in the presence of a polymerisation catalyst. | 09-19-2013 |
20130253148 | PROCESS AND APPARATUS FOR THE POLYMERISATION OF OLEFINS - The present invention relates to a process for the gas-phase polymerisation of olefins in a fluidised bed reactor, which process comprises: a) passing a fluidising gas comprising one or more olefin monomers through a fluidised bed of polymer particles in the presence of a polymerisation catalyst, b) withdrawing a first gaseous stream comprising solid particles from the top of the reactor, c) passing the first gaseous stream to a gas/solids separator, separating solid particles therefrom, and forming a second gaseous stream comprising residual solid particles, d) passing at least a portion of the second gaseous stream to one or more heat exchangers to remove the heat of reaction, and e) recycling at least a portion of the cooled stream from step (d) as the fluidising gas in step (a), characterised in that the rate of fouling of the one or more heat exchangers is such that i) the increase in pressure drop across the heat exchangers is equivalent to less than 5% per year, and/or ii) the decrease in heat transfer of the heat exchangers is equivalent to less than 5% per year. | 09-26-2013 |
20140249287 | POLYMER DEGASSING PROCESS CONTROL - The present invention relates to a process for operating a vertical fixed bed polymer powder degasser. | 09-04-2014 |