Apparatus and process for high pressure polymerization of ethylene
AssigneeExxonMobil Chemical Patents Inc.
InventorsPaul J. Clymans, Henri A. Lammens, Philip H. Cornelissen
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Abstract
Disclosed are an apparatus and a process for polymerizing ethylene under high pressure providing more than one injection point for one initiator injection pump.
Claims16
An apparatus for high pressure polymerization of ethylene, comprising a high pressure reactor in which monomer is polymerized to form a product mixture comprising polymer and unreacted monomer, wherein the reactor is provided with more than one reaction zone and one or more injection pumps in fluid connection with the reactor, wherein each one of the one or more injection pumps fluidly connects to the reactor at multiple injection points;
- and further wherein each respective injection point of the multiple injection points (a) is configured to provide initiator to a corresponding reaction zone of the more than one reaction zones;
- and (b) is provided with (b-1) a flow control valve and (b-2) a temperature controller of said corresponding reaction zone, said flow control valve and temperature controller being configured such that initiator flow to the respective injection point is controlled by the temperature controller acting on the flow control valve.
A process for high pressure polymerization of ethylene in a reactor, comprising the steps of:
- compressing monomer in a primary compressor to an intermediate pressure and then mixing the monomer with recycled monomer and further compressing the monomer in a secondary compressor upstream of the reactor, wherein the monomer is compressed in the secondary compressor to the pressure of the reactor;
- introducing compressed monomer into the high-pressure reactor, wherein the reactor is provided with more than one reaction zone;
- injecting an initiator into the reactor at multiple injection points by one or more injection pumps, wherein each one of the one or more injection pumps conducts injection at multiple injection points;
- and further wherein each respective injection point of the multiple injection points (a) provides initiator to a corresponding reaction zone of the more than one reaction zones, and (b) is provided with (b-1) a flow control valve and (b-2) a temperature controller of said corresponding reaction zone, such that flow of initiator to said respective injection point is controlled by the temperature controller acting on the flow control valve;
- contacting the monomer in the reactor with the initiator under high pressure polymerization conditions for polymerization to form a product mixture;
- releasing the product mixture through a high pressure let down valve, cooling the product mixture and separating the product mixture in a separation system having at least two stages into polymer and unreacted monomer;
- and
- recycling the unreacted monomer to the secondary compressor.
Dependencies are inferred from the claim text.