摘要:
Methods for producing elastomers or elastomeric compositions are provided. One or more C4 to C7 isoolefins and one or more comonomers can be polymerized in the presence of a diluent comprising one or more hydrofluorocarbons to provide a slurry comprising polymer product, unreacted monomer and the diluent. The slurry can be extruded to separate at least a portion of the diluent from the polymer product. The separated diluent can be recycled for polymerizing the one or more C4 to C7 isoolefins.
摘要:
A process plant for the manufacture of halobutyl rubber is provided with online monitoring and control of the process parameters to control the properties of the product. It incorporates an in-situ measurement system that does not require the removal of any sample material from the process. It uses a Fourier Transform Near Infrared (FTNIR) spectrometer, fiber-optic cables, a viscometer for measuring solution viscosity and a Resistance Temperature Device (RTD) for temperature measurement. An online real-time analyzer system using a Constrained Principal Spectral Analysis program predicts the property of the polymer product and provides the process control system with analysis of the data using derived relationships between the physical properties of the polymer and these spectral measurements and the measured values of fluid viscosity and temperature. Differences between the predicted and desired property of the product are used to control process parameters. The method can be used for a variety of chemical process plants.
摘要:
The present invention relates to a gas phase process for polymerizing one or more hydrocarbon monomer(s) in the presence of a catalyst system and a fluorinated hydrocarbon, where the fluorinated hydrocarbon is present at a partial pressure of 6.9 to 348 kPa in the reactor and the reactor temperature is from 30 to 120° C.
摘要:
Provided is a method for reducing depositions in polymerization vessels, where the method includes the steps of providing a reaction vessel having polymerization contact surfaces, polishing a majority of the polymerization contact surfaces to have an average percent excess surface areas (SAxs) of 2% or less, introducing a catalyst system and at least one monomer or comonomer mixture in the reaction vessel, and polymerizing the at least one monomer or comonomer mixture. The catalyst may be soluble in the diluent used for polymerization. The method may be useful for low temperature polymerization systems.
摘要:
Provided for herein is a process for separating a hydrocarbon-rubber from a hydrofluorocarbon diluent comprising contacting a polymer slurry comprising the hydrocarbon-rubber dispersed within the hydrofluorocarbon diluent with a hydrocarbon solvent capable of dissolving the hydrocarbon-rubber, to produce a first liquid phase and a second liquid phase, and separating the first liquid phase from the second liquid phase.
摘要:
Provided for herein is a process for separating a hydrocarbon-rubber from a hydrofluorocarbon diluent comprising contacting a polymer slurry comprising the hydrocarbon-rubber dispersed within the hydrofluorocarbon diluent with a hydrocarbon solvent capable of dissolving the hydrocarbon-rubber, to produce a first liquid phase and a second liquid phase, and separating the first liquid phase from the second liquid phase.
摘要:
The method of polymerization includes the steps of a) providing a catalyst system, b) providing at least one monomer or comonomer mixture in a reaction vessel, c) introducing the catalyst into the reaction vessel, and d) polymerizing the at least one monomer or comonomer mixture to produce an isoolefin polymer. The catalyst may be soluble in the diluent used for polymerization. The polymerization contact surfaces of the reaction vessel have an arithmetic average surface roughness of less than 0.3 μm (12 microinches).
摘要:
The present invention relates to a gas phase process for polymerizing one or more hydrocarbon monomer(s) in the presence of a catalyst system and a fluorinated hydrocarbon, where the fluorinated hydrocarbon is present at a partial pressure of 6.9 to 348 kPa in the reactor and the reactor temperature is from 30 to 120° C.
摘要:
Provided for herein is a process to produce an essentially homogeneous single liquid phase hydrocarbon-rubber cement from a polymer slurry comprising a hydrocarbon-rubber, a diluent, and unreacted monomer(s), the process comprising: (a) contacting the polymer slurry with a hydrocarbon solvent; and (b) removing the diluent in amounts not sufficiently more than is necessary to produce the essentially homogeneous single liquid phase hydrocarbon-rubber cement wherein the mass fraction of monomer(s) in the hydrocarbon-rubber cement, based on the total amount of hydrocarbon-rubber present in the hydrocarbon-rubber cement, is less than the mass fraction of monomer(s) in the hydrocarbon-rubber slurry, based on the total amount of hydrocarbon-rubber present in the hydrocarbon-rubber slurry, wherein the diluent comprises a hydrofluorocarbon.
摘要:
A method for providing mutual exclusion at a single data element level for use in embedded systems. Entries for tasks that are currently holding a resource are stored in a hold list. Entries for tasks that are not currently executing and are waiting to be freed are stored in a wait list. A single mutual exclusion semaphore flags any request to access a resource.