Compositions for removing contaminants from plastics processing equipment are described herein. The compositions may include a polymeric carrier component, an oxidizing agent, an abrasive and/or a gas agent. Methods of preparing the compositions described herein and methods of removing contaminants from plastics processing equipment are also described.

A method of operating a dump tank of a polymer production process by transferring all or a portion of a content of a polymerization reactor into the dump tank, wherein the reactor contents comprise solid polymer, and liquid and gaseous non-product components, and removing at least a portion of the liquid and gaseous non-product components from the dump tank by: reducing a pressure of the dump tank, subjecting the solid polymer to a first cleaning stage comprising heating the solid polymer by introducing a first heated treatment gas into the dump tank, and subjecting the solid polymer to a second cleaning stage comprising purging the solid polymer by introducing a second heated treatment gas into the dump tank.

A system including a dump tank to receive a reactor product comprising a polymer and hydrocarbons, including liquid hydrocarbons, the dump tank including a vessel with a reactor product inlet, a motive gas inlet, a purge gas inlet, gas outlet(s), and a fluid outlet, the motive gas inlet for introducing a motive gas into the vessel, the purge gas inlet for introducing a purge gas into the vessel, the one or more gas outlets located at a top of the vessel and the fluid outlet located at a bottom of the vessel and fluidly connected with a dump tank fluid outlet line having a dump tank outlet valve to control flow of fluid out of the dump tank via the fluid outlet; and a strainer fluidly connected with the dump tank fluid outlet line to allow passage of liquid hydrocarbons therethrough into a hydrocarbon outlet line.

A system including a dump tank to receive a reactor product comprising a polymer and hydrocarbons, including liquid hydrocarbons, the dump tank including a vessel with a reactor product inlet, a motive gas inlet, a purge gas inlet, gas outlet(s), and a fluid outlet, the motive gas inlet for introducing a motive gas into the vessel, the purge gas inlet for introducing a purge gas into the vessel, the one or more gas outlets located at a top of the vessel and the fluid outlet located at a bottom of the vessel and fluidly connected with a dump tank fluid outlet line having a dump tank outlet valve to control flow of fluid out of the dump tank via the fluid outlet; and a strainer fluidly connected with the dump tank fluid outlet line to allow passage of liquid hydrocarbons therethrough into a hydrocarbon outlet line.

The present invention relates to a catalyst composition containing: one or more selected from the group consisting of a transition metal compound represented by Formula 1 and a transition metal compound represented by Formula 3, and dialkyl L-tartrate; a cleaning liquid composition containing the catalyst composition; and a method of cleaning a polymerization apparatus using the cleaning liquid composition,

##STR00001## wherein all the variables are described herein.

A polymerization reactor for producing aqueous polymer dispersions by radically initiated emulsion polymerization of one or more ethylenically unsaturated monomers in the presence of one or more protective colloids and/or emulsifiers, is cleaned by initially charging an aqueous mixture comprising one or more ethylenically unsaturated monomers, one or more protective colloids and/or emulsifiers, but no oxidation initiator, the proportion of ethylenically unsaturated monomers being 20 to 70% by weight of the aqueous mixture, heating the aqueous mixture to a temperature of 50° C. to 100° C. for 5 minutes to 3 hours, adding one or more initiators and optionally further starting materials, initiating polymerization, removing the aqueous polymer dispersion thus obtained from the polymerization reactor and post-treating the dispersion to remove wall deposits detached during the process.

A polymerization reactor for producing aqueous polymer dispersions by radically initiated emulsion polymerization of one or more ethylenically unsaturated monomers in the presence of one or more protective colloids and/or emulsifiers, is cleaned by initially charging an aqueous mixture comprising one or more ethylenically unsaturated monomers, one or more protective colloids and/or emulsifiers, but no oxidation initiator, the proportion of ethylenically unsaturated monomers being 20 to 70% by weight of the aqueous mixture, heating the aqueous mixture to a temperature of 50° C. to 100° C. for 5 minutes to 3 hours, adding one or more initiators and optionally further starting materials, initiating polymerization, removing the aqueous polymer dispersion thus obtained from the polymerization reactor and post-treating the dispersion to remove wall deposits detached during the process.

A method of operating a dump tank of a polymer production process by transferring all or a portion of a content of a polymerization reactor into the dump tank, wherein the reactor contents comprise solid polymer, and liquid and gaseous non-product components, and removing at least a portion of the liquid and gaseous non-product components from the dump tank by: reducing a pressure of the dump tank, subjecting the solid polymer to a first cleaning stage comprising heating the solid polymer by introducing a first heated treatment gas into the dump tank, and subjecting the solid polymer to a second cleaning stage comprising purging the solid polymer by introducing a second heated treatment gas into the dump tank.

A method of operating a dump tank of a polymer production process by transferring all or a portion of a content of a polymerization reactor into the dump tank, wherein the reactor contents comprise solid polymer, and liquid and gaseous non-product components, and removing at least a portion of the liquid and gaseous non-product components from the dump tank by: reducing a pressure of the dump tank, subjecting the solid polymer to a first cleaning stage comprising heating the solid polymer by introducing a first heated treatment gas into the dump tank, and subjecting the solid polymer to a second cleaning stage comprising purging the solid polymer by introducing a second heated treatment gas into the dump tank.

The present invention relates to a catalyst composition containing: one or more selected from the group consisting of a transition metal compound represented by Formula 1 and a transition metal compound represented by Formula 3, and dialkyl L-tartrate; a cleaning liquid composition containing the catalyst composition; and a method of cleaning a polymerization apparatus using the cleaning liquid composition, ##STR00001## wherein all the variables are described herein.