Fouling in a low-density polyethylene (LDPE) tubular polymerization reactor is caused by the polyethylene/ethylene mixture forming two phases inside the reactor. Some of the polymer-rich phase is deposited on the reactor's inside wall, which considerably reduces heat-transfer rates. At a given reactor pressure, the reactor inside wall temperature is the critical parameter in determining when fouling occurs and this is controlled by the coolant stream temperatures. In this work, plant data and a heat-transfer model were used to determine the fouling thickness in a LDPE industrial reactor and the speed at which the foulant material is deposited.

Fouling in a low-density polyethylene (LDPE) tubular polymerization reactor is caused by the polyethylene/ethylene mixture forming two phases inside the reactor. Some of the polymer-rich phase is deposited on the reactor's inside wall, which considerably reduces heat-transfer rates. Phase equilibria calculations show a high degree of sensitivity of the single-phase/two-phase process fluid boundary to temperature. Almost all of the process stream is single phase and the fluid mixture is only two phase in the boundary layer close to the reactor wall where the temperature is low enough to cause phase separation. At a given reactor pressure, the reactor inside wall temperature is the critical parameter in determining when fouling occurs, and this is controlled by the coolant stream temperatures.

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Fouling in a LDPE tubular polymerization reactor is caused by the polyethylene/ethylene mixture forming two phases inside the reactor. Some of the polymer-rich phase is deposited on the reactor's inside wall, which considerably reduces heat-transfer rates. At a given reactor pressure, the reactor inside wall temperature is the critical parameter in determining when fouling occurs and this is controlled by the coolant stream temperatures. Fouling upstream of a reacting zone increases the inlet temperature to that zone. This increase in temperature results in high hotspot temperatures, low fractional conversion, and broader polymer molecular weight distribution.

No abstract