# US 7,745,568 B2 · Transfer vessel between flash tank and purge column

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- Number: US 7,745,568 B2
- Document ID: US7745568B2
- Status: Granted
- Kind: B2
- Application number: 10/589,203
- Filed: 2005-02-08
- Published: 2008-03-06
- Granted: 2010-06-29
- Earliest claimed: 2004-02-13
- Assignees: Total Petrochemicals Research Feluy
- Inventors: Hugo Vandaele
- Web page: https://patentgrep.com/patent/US7745568B2

## CPC

- C08F 6/003: {from polymer solutions, suspensions, dispersions or emulsions without recovery of the polymer therefrom}
- B01J 8/003: {in a downward flow}
- B01J 8/20: with liquid as a fluidising medium
- B01J 19/2435: {Loop-type reactors}
- C08F 6/005: {from solid polymers}
- B01J 2208/00548: Flow
- B01J 2208/00761: Discharging
- B01J 2219/00202: at the reactor outlet
- B01J 2219/00218: Dynamically variable (in-line) parameter values
- B01J 2219/00236: at the reactor outlet
- C08F: MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS

## Abstract

A process is provided for recovering polymer solids from a polymerisation reactor effluent. The process comprises extracting the polymerisation effluent from a polymerisation reactor; passing the effluent, or a part thereof, to a flash vessel for flashing liquid in the effluent to vapour, and removing said vapour from said flash vessel; passing the polymer solids from the flash vessel to a transfer apparatus which comprises a transfer vessel; passing the polymer solids from the transfer vessel to a purging means for removing residual liquid from the polymer solids; wherein the polymer solids are passed from the flash vessel to the purging means in a continuous flow such that a quantity of polymer solids is maintained in the transfer vessel. An apparatus for performing the process is also provided.

## Claims

### Claim 1

A method for the recovery of a slurry of polymer solids from a polymerization reactor comprising:
recovering a slurry comprising polymer solids in a liquid medium from a loop reactor through a settling leg via a discharge valve;
passing the slurry from the loop reactor to a flash vessel;
reducing a pressure of the slurry from a first pressure to a second pressure within the flash vessel to vaporize the liquid medium and form vapor;
removing at least a portion of the vapor from the flash vessel to form a concentrated slurry;
passing the concentrated slurry from the flash vessel to a transfer vessel;
measuring a level of polymer solids within the flash vessel;
continuously withdrawing an amount of polymer solids from the transfer vessel and passing the amount of polymer solids from the transfer vessel to a purge vessel, the amount adapted to maintain the level of polymer solids within the flash vessel at a predetermined level;
removing remaining liquid from the polymer solids within the purge vessel; and
recovering the polymer solids from the purge vessel.

### Claim 2 (depends on 1)

The method of claim 1 further comprising passing a nitrogen containing gas through the purge vessel to remove accumulated liquid from the polymer slurry in the purge vessel.

### Claim 3 (depends on 1)

The method of claim 1, wherein the predetermined level of polymer solids seals the flash vessel from the purge vessel.

### Claim 4 (depends on 1)

The method of claim 1, wherein the polymer solids comprise an olefin polymer.

### Claim 5

A system for the recovery of a polymer from a polymerization reactor comprising:
a polymerization loop reactor adapted to contact an olefin monomer with a catalyst system to form an olefin polymer within a polymer slurry and comprising a settling leg;
a flash vessel operably connected to the settling leg of the polymerization reactor and adapted to receive the polymer slurry and vaporize at least a portion of diluent from the polymer slurry;
a purge vessel adapted to separate remaining diluent from the polymer slurry;
a transfer vessel disposed between the flash vessel and the purge vessel;
a first valve disposed between the flash vessel and the transfer vessel; and
a second valve disposed between the transfer vessel and the purge vessel, the first and second valves adapted to maintain a predetermined level of polymer slurry within the purge vessel.

### Claim 6 (depends on 5)

The system of claim 5 further comprising a control system operably connected to the first valve and the second valve and adapted to communicate with the same.

### Claim 7 (depends on 6)

The system of claim 6, wherein the control system is adapted to measure a level of polymer slurry within the transfer vessel.