Polyethylene Manufacturing System and Method

An ethylene polymerization system comprising:

• a first compressor that provides monomer under relatively low pressure;
• a second compressor located downstream of and in fluid communication with the first compressor, wherein the second compressor pressurizes the monomer to a relatively high pressure;
• a high pressure reactor downstream of and in fluid communication with the second compressor, wherein the high pressure polymerization reactor polymerizes the monomer to produce a product mixture including polymer and unreacted monomer;
• a high pressure let down valve located downstream of and in fluid communication with the high pressure reactor through which the product mixture from the high pressure reactor flows;
• a separation system downstream of the high pressure let down valve that separates gas from the product mixture and produces a stream of off gas that is recycled into a feed that flows into a suction port of the second compressor;
• and
• a quench system that cools the product mixture entering the separation system, the quench system including a jet pump located downstream of the high pressure let down valve having a suction inlet that receives all or substantially all of the monomer under relatively low pressure from the first compressor such that the pressure of the flow of monomer from the first compressor is less than or about equal to a suction pressure of the second compressor.

An ethylene polymerization system comprising:

• a first compressor including a spillback valve that provides monomer under relatively low pressure;
• a second compressor located down stream of and in fluid communication with the first compressor, wherein the second compressor pressurizes the monomer to a relatively high pressure;
• a high pressure reactor located downstream of and in fluid communication with the second compressor that polymerizes the monomer to produce a product mixture comprising polymer and unreacted monomer;
• a high pressure let down valve downstream of and in fluid communication with the high pressure reactor through which the product mixture from the high pressure reactor flows;
• a separation system downstream of and in fluid communication with the high pressure let down valve that separates gas from the product mixture and produces a stream of off gas that is recycled into a feed that flows into a suction port of the second compressor;
• and
• a quench system that cools the product mixture entering the separation system, the quench system including a jet pump downstream of the high pressure let down valve having a suction inlet that receives all or substantially all of the low pressure flow of monomer from the first compressor such that the pressure of the flow of monomer from the first compressor is less than or about equal to a suction pressure of the second compressor, and a control system that controls the suction pressure of the second compressor at a desired set point by modulating the spillback valve of the first compressor which in turn modulates the monomer under relatively low pressure from the first compressor to the jet pump.

A method of providing a quenching to a product stream generated by an ethylene polymerization system that includes a first compressor that provides monomer under relatively low pressure;

• a second compressor located down stream of and in fluid communication with the first compressor that pressurizes to a relatively low pressure to a monomer under relatively high pressure;
• a high pressure reactor downstream of and in fluid communication with the second compressor that polymerizes the monomer to a product mixture;
• a high pressure let down valve located downstream of and in fluid communication with the reactor through which the product mixture from the high pressure reactor flows, and a separation system downstream of the high pressure let down valve that receives the flow of product mixture, comprising:
• providing a pump between the high pressure let down valve and the separation system;
• directing the product mixture flow through the pump;
• and
• directing substantially all of the monomer under relatively low pressure from the first compressor to a suction inlet of the pump.