LNG cold energy recovery by using ice slurry

A LNG cold energy recovery system comprising:

• a. an LNG regasification heat exchanger, the LNG regasification heat exchanger receiving LNG at −162° C. and vaporizing the LNG to natural gas;
• b. an ice slurry production tank having a top layer having a light solvent, a middle layer having water and a bottom layer having a heavy solvent;
• wherein the middle layer comprises water, ice particles and a freezing point depressant, wherein the top, middle and bottom layers are different liquids with different densities and immiscible to each other, and wherein toluene is chilled by the LNG regasification heat exchanger and fed into the bottom layer, thereby forming toluene bubbles having less density than the middle layer;
• c. a superheater heat exchanger, wherein the natural gas from said LNG regasification heat exchanger is heated to a temperature above +2° C. in the natural gas superheater heat exchanger;
• wherein the heating medium for said superheater heat exchanger is an aqueous solution of a freezing point depressant which can be cooled to a temperature below 0° C. at an exit of the superheater heat exchanger, and where in the freezing point depressant is a substance selected from a group consisting LiCl, NaCl, ethylene glycol, propylene glycol, KAc (potassium acetate) and potassium formate (KCOOH);
• d. an ice slurry separation tank for separating an ice slurry stream from a toluene stream from the ice slurry production tank;
• wherein the terminal velocity of a toluene bubble of 5 mm in diameter is Vt m/s whereas the hindered settling velocity of an ice particle of 1 mm in diameter Vs m/s, wherein, for the downward ice slurry flow at a bottom section of the ice slurry separation tank, the bulk flow velocity is maintained higher than Vs m/s but lower than Vt m/s, and wherein, for the upward toluene flow exiting through a nozzle located at the top section of the ice slurry separation tank, the nozzle is located where the level of the nozzle can prevent entrainment of blanketing nitrogen gas and the ice slurry;
• e. an ice slurry storage tank for receiving ice slurry from the ice slurry separation tank;
• where in the ice slurry storage tank operates continuously for LNG cold energy recovery while charging and discharging ice slurry at the same time, wherein the ice slurry storage tank is charged with ice slurry from the ice slurry separation tank, wherein the ice slurry storage tank discharges ice slurry at least to cold energy users, and wherein the ice slurry storage tank is sized for a capacity sufficiently large enough for the continuous operation by storing the excess ice slurry and discharging it during the hours for the deficient amount to users;
• and
• f. a CO2 liquefaction heat exchanger, the ice slurry from the ice slurry storage tank discharged to the CO2 liquefaction heat exchanger for CCUS (Carbon Capture, Utilization, and Storage);
• wherein the CO2 liquefaction heat exchanger condenses CO2 gas by using the ice slurry generated with the LNG cold energy recovered, said CO2 gas 482 is fed from CO2 capture processes, said ice slurry is available for CO2 liquefaction from −45° C., said CO2 gas is liquefied at −30° C. and 15 bar for transport, said ice slurry is supplied at temperatures higher than −45° C. in order to condense CO2 gas at higher pressures, said CO2 gas is liquefied for temporary storage for CCUS, and said recovered LNG cold energy is used to cool the CO2 gas during the compression process for CCUS.