System and method for improving dump tank purge time

A method comprising:

• introducing a polymer product from a polymerization reactor into a dump tank of a dump tank system comprising:
• a dump tank configured to receive a reactor product comprising a polymer and hydrocarbons, including liquid hydrocarbons, wherein the dump tank comprises a vessel having a reactor product inlet, a motive gas inlet, a purge gas inlet, one or more gas outlets, and a fluid outlet, wherein the motive gas inlet is configured to introduce a motive gas into an upper portion of the vessel, wherein the purge gas inlet is configured to introduce a purge gas into a lower portion of the vessel, wherein the one or more gas outlets are located at a top of the vessel, and wherein the fluid outlet is 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, wherein the strainer is fluidly connected with the dump tank fluid outlet line and allows passage of liquid hydrocarbons therethrough into a hydrocarbon outlet line and prevents passage therethrough of particles having a retained particle size of greater than about 150 micrometers (μm);
• and
• draining liquid hydrocarbons from the dump tank by:
• opening the dump tank outlet valve on the dump tank fluid outlet line and introducing motive gas via the motive gas inlet, whereby fluid comprising liquid hydrocarbons and motive gas flows out the fluid outlet to the strainer, whereby the liquid hydrocarbons pass through the strainer to the hydrocarbon outlet line and particles having the particle size greater than the retained particle size are prevented passage through the strainer to the hydrocarbon outlet line;
• monitoring the hydrocarbon outlet line to determine when a majority of the liquid hydrocarbons have been removed from the vessel;
• and
• ceasing the introducing of the motive gas into the dump tank and closing the dump tank outlet valve.

A method comprising:

• introducing a polymer product from a polymerization reactor into a dump tank, wherein the polymer product comprises a polymer and hydrocarbons, including liquid hydrocarbons, and wherein the dump tank comprises:
• a vessel having a reactor product inlet, a motive gas inlet, a purge gas inlet, one or more gas outlets, and a fluid outlet, wherein the motive gas inlet is configured to introduce a motive gas into an upper portion of the vessel, wherein the purge gas inlet is configured to introduce a purge gas into a lower portion of the vessel, wherein the one or more gas outlets are located at a top of the vessel, and wherein the fluid outlet is 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, wherein the dump tank outlet valve is in a closed position during the introducing of the polymer product into the dump tank from the reactor;
• and
• draining liquid hydrocarbons from the dump tank by:
• opening the dump tank outlet valve on the fluid outlet line and introducing motive gas at a motive gas pressure via the motive gas inlet, whereby liquid hydrocarbons flow out the fluid outlet to a strainer, whereby the liquid hydrocarbons pass, as a strained liquid, through the strainer to a hydrocarbon outlet line and particles having the particle size greater than a retained particle size are prevented passage through the strainer to the hydrocarbon outlet line, wherein the strainer is fluidly connected with the fluid outlet line and has a strainer mesh size that allows passage of liquid hydrocarbons therethrough into the hydrocarbon outlet line and prevents passage therethrough of particles having a retained particle size of greater than about 150 micrometers (μm);
• and
• maintaining a pressure of the dump tank at a draining pressure of greater than a vapor pressure of the hydrocarbons in the polymer product until a majority of the liquid hydrocarbons have been removed from the vessel, such that a majority of the hydrocarbons remain liquid during the draining;
• and
• ceasing the introducing of the motive gas into the dump tank and closing the dump tank outlet valve.