US 3,998,995 A · Polymerization method and apparatus

Abstract

Polymerization of a monomer, either alone or present in major proportion with one or more comonomers present in minor proportion, is accomplished by controlling the major monomer feed rate in response to a signal representative of the production rate of the polymerization process, unless the major monomer concentration within the reaction zone exceeds a preselected high limit causing the major monomer feed rate to be controlled in response to the concentration of the major monomer within the reaction zone. The flow of recycle diluent to the reaction zone is controlled in response to the concentration of major monomer within the reaction zone unless the solids concentration within the reaction zone exceeds a preselected high limit, in which case the flow of recycle diluent to the reaction zone is controlled in response to the concentration of solids within the reaction zone. Under ordinary operating conditions, when the preselected maximums have not been exceeded, the flow of major monomer to the reaction zone is controlled in response to the polymer production rate and the flow of recycle diluent to the reaction zone is controlled in response to the concentration of major monomer within the reaction zone.

Claims48

Dependent claims

A method for controlling a polymerization reaction, said method comprising the steps of:

generating a monomer concentration signal representative of the concentration of an unpolymerized monomer within a reaction zone;
controlling the flow rate of said monomer to said reacton zone in response to a preselected production rate set point signal representative of a desired rate of production of polymer within said reaction zone to provide monomer feed sufficient to maintain a preselected production rate;
and
automatically ceasing said step of controlling the flow rate of said monomer to said reaction zone in response to said production rate set point signal and initiating the step of controlling the flow rate of said monomer to said reaction zone in response to said monomer concentration signal to maintain monomer concentration within said reaction zone below a predetermined level, when said monomer concentration signal exceeds a predetermined value.

1 more element

Apparatus comprising:

polymerization reactor means;
means for removing a polymeric product from said reactor means;
monomer feed conduit means communicating with said reactor means for carrying a monomer to be polymerized into said reactor means;
means for controlling the flow rate of monomer through said monomer feed conduit means to said reactor means in response to a monomer flow rate set point signal;
means for providing a production rate set point signal representative of a desired polymeric product production rate within said reactor means;
first signal generating means for generating a production rate signal representative of the rate at which polymer is being produced within said reactor means;
second signal generating means for generating a monomer concentration signal representative of the concentration of said monomer within said reactor means;
monomer set point generating means for generating said monomer flow rate set point signal, having a value corresponding to the monomer feed flow required to provide the desired production rate, in response to said production rate set point signal, for ceasing the generation of said monomer flow rate set point signal from said production rate set point signal and initiating the generation of said monomer flow rate set point signal, having a value corresponding to the monomer feed rate required to maintain monomer concentration within said reaction zone below a predetermined level, in response to said monomer concentration signal when said monomer concentration signal exceeds a predetermined value, and for reinstating the generation of said monomer flow rate set point signal from said production rate set point signal when said monomer concentration signal goes below a predetermined value and said production rate signal is within a predetermined range.

5 more elements

Apparatus comprising:

polymerization reactor means;
means for removing a polymeric product from said reactor means;
monomer feed conduit means communicating with said reactor means for carrying a monomer to be polymerized into said reactor means;
diluent feed conduit means communicating with said reactor means for carrying a diluent into said reactor means;
means for controlling the flow rate of diluent through said diluent feed conduit to said reactor means in response to a diluent flow rate set point signal;
first signal generating means for generating a monomer concentration signal representative of the concentration of said monomer within said reactor means;
second signal generating means for generating a solids concentration signal representative of the concentration of polymerized material within said reactor means;
and
diluent set point generating means for generating said diluent flow rate set point signal, having a value corresponding to the diluent flow rate required to provide the desired monomer concentration within said reaction zone, in response to said monomer concentration signal, for ceasing generation of said diluent flow rate set point signal from said monomer concentration signal and initiating generation of said diluent flow rate set point signal, having a value corresponding to the diluent flow rate required to maintain solids concentration within said reaction zone below a predetermined level, in response to said solids concentration signal when said solids concentration signal exceeds a preselected maximum value, and for reinitiating generation of said diluent flow rate set point signal from said monomer concentration signal when said solids concentration signal goes below said preselected maximum value and said production rate signal is within a preselected range.

6 more elements

A method for controlling a polymerization reaction, said method comprising the steps of:

generating a monomer concentration signal representative of the concentration of an unpolymerized monomer with said reaction zone;
controlling the flow rate of said monomer to said reaction zone in response to a preselected production rate set point signal representative of a desired rate of production of polymer within said reaction zone to provide monomer feed sufficient to maintain a preselected production rate within said reaction zone;
and
automatically ceasing said step of controlling the flow rate of said monomer to said reaction zone in response to said production rate set point signal and initiating the step of controlling the flow rate of said monomer to said reaction zone in response to comparison of a preselected high monomer concentration set point signal with said monomer concentration signal to maintain monomer concentration within said reaction zone below a predetermined level, when said monomer concentration signal exceeds a predetermined value.

1 more element

A method for controlling a polymerization reaction, said method comprising the steps of:

generating a monomer concentration signal representative of the concentration of an unpolymerized monomer within said reaction zone;
generating a solids concentration signal representative of the concentration of polymerized material within said reaction zone;
controlling the flow rate of diluent to said reaction zone in response to comparison of a preselected monomer concentration set point signal with said monomer concentration signal to provide diluent feed sufficient to maintain a predetermined monomer concentration within said reaction zone;
and
automatically ceasing step of controlling the flow rate of said diluent in response to comparison of said monomer concentration set point signal with said monomer concentration signal and initiating the step of controlling the flow rate of said diluent to said reaction zone in response to comparison of a preselected high solids concentration set point signal with said solids concentration signal to maintain solids concentration within said reaction zone below a predetermined level when said solids concentration signal exceeds a preselected value.

2 more elements

Dependencies are inferred from the claim text.

Polymerization method and apparatus

Life of this patent

Polymerization method and apparatus

Life of this patent

Abstract

Claims48