Methods of controlling olefin polymerization reactor systems are provided herein. In some aspects, the methods include a) selecting n input variables, each input variable corresponding to a process condition for an olefin polymerization process; b) identifying m response variables, each response variable corresponding to a measurable polymer property; c) adjusting one of more of the n input variables in a plurality of polymerization reactions using the olefin polymerization reactor system, to provide a plurality of olefin polymers and measuring each of the m response variables as a function of the input variables for each olefin polymer; d) analyzing the change in each of the response variables as a function of the input variables to determine the coefficients; e) calculating a Response Surface Model (RSM) using general equations for each response variable determined in step d) to correlate any combination of the n input variables with one or more of m response variables; f) applying n selected input variables to the calculated Response Surface Model (RSM) to predict one or more of m target response variables, each target response variable corresponding to a measurable polymer property; and g) using the n selected input variables I.sup.s1 to I.sup.sn to operate the olefin polymerization reactor system and provide a polyolefin product.

Methods and systems for controlling a polymerization reaction in a non-sticking regime are disclosed. An exemplary method includes measuring parameters for the polymerization reaction including a reactor temperature and a concentration of an induced condensing agent (ICA) in a polymerization reactor. An equivalent partial pressure ((P.sub.ICA).sub.equiv) of the ICA is calculated. The polymerization reaction is located in a two dimension space defined by a reactor temperature dimension and a ((P.sub.ICA).sub.equiv) dimension. The location in the two dimensional space is compared to an non-sticking regime, defined as the space between an upper temperature limit (UTL) curve and a lower temperature limit (LTL) curve. The parameters of the polymerization reaction are adjusted to keep the polymerization reaction within the non-sticking regime.

Methods and systems for controlling a polymerization reaction in a non-sticking regime are disclosed. An exemplary method includes measuring parameters for the polymerization reaction including a reactor temperature and a concentration of an induced condensing agent (ICA) in a polymerization reactor. An equivalent partial pressure ((P.sub.ICA).sub.equiv) of the ICA is calculated. The polymerization reaction is located in a two dimension space defined by a reactor temperature dimension and a ((P.sub.ICA).sub.equiv) dimension. The location in the two dimensional space is compared to an non-sticking regime, defined as the space between an upper temperature limit (UTL) curve and a lower temperature limit (LTL) curve. The parameters of the polymerization reaction are adjusted to keep the polymerization reaction within the non-sticking regime.

Methods and systems for controlling a polymerization reaction in a non-sticking regime are disclosed. An exemplary method includes measuring parameters for the polymerization reaction including a reactor temperature and a concentration of an induced condensing agent (ICA) in a polymerization reactor. An equivalent partial pressure ((P.sub.ICA).sub.equiv) of the ICA is calculated. The polymerization reaction is located in a two dimension space defined by a reactor temperature dimension and a ((P.sub.ICA).sub.equiv) dimension. The location in the two dimensional space is compared to an non-sticking regime, defined as the space between an upper temperature limit (UTL) curve and a lower temperature limit (LTL) curve. The parameters of the polymerization reaction are adjusted to keep the polymerization reaction within the non-sticking regime.

A process to form an ethylene-based polymer including polymerizing ethylene and at least one asymmetrical polyene comprising an “alpha, beta unsaturated-carbonyl end” (“α,β-unsaturated-carbonyl end”) and a “C—C double bond end,” wherein the polymerization takes place in the presence of at least one free-radical initiator; and wherein the polymerization takes place in a reactor configuration comprising at least two reaction zones, reaction zone 1 and reaction zone i (i>2), wherein reaction zone i is downstream from reaction zone 1.

Techniques and systems for reducing fouling in a polymerization system are described. The polymerization system includes a reactor coupled to a recycle system. The recycle system includes at least one fouling-susceptible unit. The technique includes inducing polymerization of a reactant, for example, at least one olefin monomer reactant, with a catalyst in the reactor. The technique may further include circulating a fluidizing stream through the reactor and the at least one fouling-susceptible unit. The fluidizing stream may include entrained particles tending to foul the at least one fouling-susceptible unit. The technique can further include contacting the fluidizing stream with a catalyst poison at at least one location upstream of the at least one fouling-susceptible unit in the recycle system.

Described herein are methods for continuous solution polymerization. The method may comprise polymerizing one or more monomers and comonomers in the presence of a solvent in a polymerization reactor to produce a polymer solution; determining the composition of the polymer solution exiting the polymerization reactor in an on-line fashion; determining at least one of the critical pressure or critical temperature; comparing the critical pressure and/or critical temperature to the actual temperature of the polymer solution and the actual pressure of the polymer solution; heating or cooling the polymer solution to a temperature within 50° C. of the critical temperature; and passing the polymer solution through a pressure letdown valve into a liquid-liquid separator, where the pressure of the polymer solution is reduced or raised to a pressure within 50 psig of the critical pressure to induce a separation of the polymer solution into two liquid phases.

Described herein are methods for continuous solution polymerization. The method may comprise polymerizing one or more monomers and comonomers in the presence of a solvent in a polymerization reactor to produce a polymer solution; determining the composition of the polymer solution exiting the polymerization reactor in an on-line fashion; determining at least one of the critical pressure or critical temperature; comparing the critical pressure and/or critical temperature to the actual temperature of the polymer solution and the actual pressure of the polymer solution; heating or cooling the polymer solution to a temperature within 50° C. of the critical temperature; and passing the polymer solution through a pressure letdown valve into a liquid-liquid separator, where the pressure of the polymer solution is reduced or raised to a pressure within 50 psig of the critical pressure to induce a separation of the polymer solution into two liquid phases.

Systems and methods for monitoring a particle/fluid mixture are provided. The method can include flowing a mixture comprising charged particles and a fluid past a particle accumulation probe. The method can also include measuring electrical signals detected by the probe as some charged particles pass the probe without contacting the probe while other charged particles contact the probe. The measured electrical signals can be manipulated to provide an output. The method can also include determining from the output if the charged particles contacting the probe have, on average, a different charge than the charged particles that pass the probe without contacting the probe.

Systems and methods for monitoring a particle/fluid mixture are provided. The method can include flowing a mixture comprising charged particles and a fluid past a particle accumulation probe. The method can also include measuring electrical signals detected by the probe as some charged particles pass the probe without contacting the probe while other charged particles contact the probe. The measured electrical signals can be manipulated to provide an output. The method can also include determining from the output if the charged particles contacting the probe have, on average, a different charge than the charged particles that pass the probe without contacting the probe.