Impurity control for a high pressure CO2 purification and supply system

In an apparatus for producing a purified, pressurized liquid carbon dioxide stream, including a liquid carbon dioxide supply tank (10) for distilling off a feed stream comprising carbon dioxide vapor, at least one purifying filter (13,14) for purifying the carbon dioxide vapor feed stream to form a purified carbon dioxide vapor feed stream, a condenser (18) for condensing the purified carbon dioxide vapor feed stream to form an intermediate liquid carbon dioxide stream, a receiver (20) for accumulating the intermediate liquid carbon dioxide stream, a high-pressure accumulation chamber (30) for accepting the intermediate liquid carbon dioxide stream from the receiver (20), a heater (31) for heating the high-pressure accumulation chamber (30) for pressurizing the carbon dioxide liquid contained in the high-pressure accumulation chamber to a delivery pressure, a sensor (45) for detecting when the high-pressure accumulation chamber (30) requires replenishment of liquid carbon dioxide (10), a flow network having conduits connecting the liquid carbon dioxide supply tank to the condenser, the condenser to the receiver, the receiver to the high-pressure accumulation chamber, and for discharging the pressurized liquid carbon dioxide stream from the high-pressure accumulation chamber, the conduits of said flow network including a vent line (51) from the high-pressure accumulation chamber (30) to the condenser (18) to facilitate introduction of the intermediate liquid carbon dioxide stream into the high-pressure accumulation chamber, and the flow network having valves (46,47,48,12,15) associated with said conduits to allow for isolation of the condenser (18), the receiver (20), the high-pressure accumulation chamber (30), and the at least one purifying filter (13,14) of the apparatus, wherein the improvement comprises:

• a distillation column (M) having packing (N) therein for receiving the purified carbon dioxide vapor feed stream (L) in the packing;
• the condenser (18) in fluid communication with the distillation column (M) for condensing a first portion (O) of the purified carbon dioxide vapor feed stream (L) within the condenser to form another intermediate liquid carbon dioxide stream (T) and a liquid vent stream (Q);
• and
• a receiver (20) for receiving the another intermediate liquid carbon dioxide stream (T) into the receiver, and an outlet in the distillation column (M) through which is vented the liquid vent stream (Q).

In an apparatus for producing a purified, pressurized liquid carbon dioxide stream, including a liquid carbon dioxide supply tank (10) for distilling off a feed stream comprising carbon dioxide vapor, at least one purifying filter (13,14) for purifying the carbon dioxide vapor feed stream to form a purified carbon dioxide vapor feed stream, a condenser (18) for condensing the purified carbon dioxide vapor feed stream to form an intermediate liquid carbon dioxide stream, a receiver (20) for accumulating the intermediate liquid carbon dioxide stream, a high-pressure accumulation chamber (30) for accepting the intermediate liquid carbon dioxide stream from the receiver (20), a heater (31) for heating the high-pressure accumulation chamber (30) for pressurizing the carbon dioxide liquid contained in the high-pressure accumulation chamber to a delivery pressure, a sensor (45) for detecting when the high-pressure accumulation chamber (30) requires replenishment of liquid carbon dioxide (10), a flow network having conduits connecting the liquid carbon dioxide supply tank to the condenser, the condenser to the receiver, the receiver to the high-pressure accumulation chamber, and for discharging the liquid carbon dioxide stream from the high-pressure accumulation chamber, the conduits of said flow network including a vent line (51) from the high-pressure accumulation chamber (30) to the condenser (18) to facilitate introduction of the intermediate liquid carbon dioxide stream into the high-pressure accumulation chamber, and the flow network having valves (46,47,48,12,15) associated with said conduits to allow for isolation of the condenser (18), the receiver (20), the high-pressure accumulation chamber (30), and the at least one purifying filter (13,14) of the apparatus, wherein the improvement comprises;

• a distillation column (B) having packing (C) therein and a sump (D) below the packing, the distillation column in fluid communication with the liquid carbon dioxide supply tank for receiving the liquid carbon dioxide stream and wherein the packing is for stripping volatile impurities from the liquid carbon dioxide stream;
• another heater (E) in contact with liquid carbon dioxide in the sump (D) for vaporizing the liquid carbon dioxide in the sump;
• a vent in the distillation column (B) from which a first vaporized portion (G) of carbon dioxide vapor in the sump (D) is withdrawn from the distillation column;
• a conduit (I) in fluid communication with the sump (D) and from which a second vaporized portion (H) of the carbon dioxide vapor in the sump is withdrawn into the conduit (I) to be introduced into the carbon dioxide vapor feed stream;
• and
• another distillation column (M) having an outlet, and another packing (N) in the another distillation column for receiving the purified carbon dioxide vapor feed stream (L) in the another packing;
• the condenser (18) in fluid communication with the distillation column (M) for condensing a first portion (O) of the purified carbon dioxide vapor feed stream (L) within the condenser to form another intermediate liquid carbon dioxide stream (T) and a liquid vent stream (Q);
• and
• a receiver (20) for receiving the another intermediate liquid carbon dioxide stream (T) into the receiver, wherein the outlet in the another distillation column (M) is through which the liquid vent stream (Q) is vented.