Method for preventing or inhibiting fouling in a gas-phase polyolefin polymerization process
A method for preventing or inhibiting fouling in a gas-phase polyolefin polymerization process. The method includes maintaining the inside surface temperature of the process equipment below the dew point temperature of the gas mixture passing through the equipment.
1. A method for preventing or inhibiting fouling in a gas-phase polyolefin polymerization process, comprising:
passing a gas mixture having an average temperature above its dew point temperature through process equipment; and
maintaining the inside surface temperature of the equipment below the dew point temperature of the gas mixture.
2. The method according to claim 1 , wherein the maintaining step comprises adding an inert condensable compound to the gas mixture.
3. The method according to claim 2 , wherein the inert condensable compound is a saturated hydrocarbon.
4. The method according to claim 3 , wherein the saturated hydrocarbon comprises butane, pentane, hexane, or mixtures thereof.
5. The method according to claim 1 , wherein the maintaining step comprises decreasing the velocity of the gas mixture flowing through the equipment.
6. The method according to claim 1 , wherein the process equipment comprises piping, heat exchangers, cyclone separators, gas ejectors, compressors, reactors, or combinations thereof.
7. A method for preventing or inhibiting fouling in a gas-phase polyolefin polymerization process, comprising:
diverting at least a portion of a gas mixture flowing through equipment in the polymerization process through a by-pass around the equipment;
maintaining the inside surface temperature of the equipment below the dew point temperature of the gas mixture; and
combining the portion of the gas mixture flowing through the by-pass with the portion of the gas mixture flowing through the equipment to form a combined gas mixture having an average temperature above the combined gas mixture's dew point temperature.
8. The method according to claim 7 , wherein the maintaining step comprises adding an inert condensable compound to the gas mixture.
9. The method according to claim 8 , wherein the inert condensable compound is a saturated hydrocarbon.
10. The method according to claim 9 , wherein the saturated hydrocarbon comprises butane, pentane, hexane, or mixtures thereof.
11. The method according to claim 7 , wherein the process equipment comprises heat exchangers.