Abstract: The present invention relates to a method for preparing carbon nanotubes, the method including: preparing a support including AlO(OH) by primary heat treatment of Al(OH)3; preparing an active carrier by supporting a mixture including a main catalyst precursor and a cocatalyst precursor on the support; drying the active carrier through multi-stage drying including vacuum drying; preparing a supported catalyst by secondary heat treatment of the dried active support; and preparing carbon nanotubes in the presence of the supported catalyst, and the carbon nanotubes prepared by the method as described above can remarkably improve conductivity.

Abstract: A target gas separation method using a deep cooling process includes a first process operation including a first thawing operation of blocking the first gas inlet unit and introducing inlet gas to the second heat exchanger through the second gas inlet unit to thaw the second heat exchanger and a first freezing operation transferring gas flowing into the second heat exchanger to the first heat exchanger through the second connection pipe to freeze target gas in the first heat exchanger, and a second process operation including a second thawing operation of blocking the second gas inlet unit and introducing inlet gas to the first heat exchanger through the first gas inlet unit to thaw the first heat exchanger and a second freezing operation of transferring gas flowing into the first heat exchanger to the second heat exchanger through the first connection pipe to freeze the target gas in the second heat exchanger, and wherein, after the first process operation is performed for a designated time, the second proce

Abstract: Provided is a gas separation method including: a first process operation including a first freezing operation of blocking a second gas inlet unit, a first transfer operation of sublimating or evaporating the frozen target gas in a second heat exchanger and a first thawing operation of reintroducing the target gas transferred to the second compressor to the second heat exchanger and thawing the second heat exchanger; and a second process operation including a second freezing operation of blocking the first gas inlet unit, a second transfer operation of sublimating or evaporating the frozen target gas in the first heat exchanger and a second thawing operation of reintroducing the target gas transferred to the first compressor to the first heat exchanger and thawing the first heat exchanger, wherein the first process operation is performed for a specified time and then the second process operation is performed for a specified time.

Abstract: A gas dispersion device capable of improving the performance of a rectangular scrubber includes: a scrubber having a rectangular shape; and a gas inlet configured to introduce gas into the scrubber, the gas inlet being mounted on the scrubber and having a rectangular shape.

Abstract: The present disclosure relates to a spray apparatus for improving the performance of a rectangular-shaped scrubber which may efficiently remove harmful substances in a gas by mounting an injector for spraying a liquid in a rectangular pyramid shape on a scrubber having a rectangular shape. The spray apparatus includes: a scrubber having a rectangular shape; and an injector mounted on the scrubber and including a spray nozzle configured to spray a liquid in a rectangular pyramid shape.

Abstract: A membrane apparatus including a housing, a forward osmosis membrane dividing an internal space of the housing into an inlet region and a mixing region, and a pervaporation membrane dividing the internal space of the housing into the mixing region and a discharge region. The forward osmosis membrane separates a preliminary filtration liquid from an inlet liquid and provides the separated preliminary filtration liquid to the mixing region, the preliminary filtration liquid is mixed with a forward osmosis draw solution to make a mixed solution, the pervaporation membrane separates a final filtration liquid from the mixed solution and provides the separated final filtration liquid to the discharge region, the final filtration liquid is vaporized in the discharge region to make vapor, and an amount of the vapor is adjusted by at least one of a temperature of the mixed solution and a degree of vacuum of the discharge region.

Abstract: Disclosed is a vapor splitter including: a chimney tray dividing an internal space of a housing into an upper space and a lower space; a chimney provided on the chimney tray to enable the upper space and the lower space to communicate with each other; a cap covering the chimney with a gap therebetween such that a gas discharge hole is formed so that gas, coming out through the chimney, can be transferred to the upper space through the gas discharge hole; a liquid feeding unit for feeding liquid to the upper space; and a liquid discharging unit for discharging the liquid out of the upper space. The size of the gas discharge hole is adjusted by controlling the height of the liquid collected on the chimney. Further disclosed is a method of adjusting a vapor split ratio using the vapor splitter.

Abstract: A membrane apparatus including a housing, a forward osmosis membrane dividing an internal space of the housing into an inlet region and a mixing region, and a pervaporation membrane dividing the internal space of the housing into the mixing region and a discharge region. The forward osmosis membrane separates a preliminary filtration liquid from an inlet liquid and provides the separated preliminary filtration liquid to the mixing region, the preliminary filtration liquid is mixed with a forward osmosis draw solution to make a mixed solution, the pervaporation membrane separates a final filtration liquid from the mixed solution and provides the separated final filtration liquid to the discharge region, the final filtration liquid is vaporized in the discharge region to make vapor, and an amount of the vapor is adjusted by at least one of a temperature of the mixed solution and a degree of vacuum of the discharge region.

Abstract: Disclosed is a vapor splitter including: a chimney tray dividing an internal space of a housing into an upper space and a lower space; a chimney provided on the chimney tray to enable the upper space and the lower space to communicate with each other; a cap covering the chimney with a gap therebetween such that a gas discharge hole is formed so that gas, coming out through the chimney, can be transferred to the upper space through the gas discharge hole; a liquid feeding unit for feeding liquid to the upper space; and a liquid discharging unit for discharging the liquid out of the upper space. The size of the gas discharge hole is adjusted by controlling the height of the liquid collected on the chimney. Further disclosed is a method of adjusting a vapor split ratio using the vapor splitter.

Abstract: A method of regenerating an ammonium bicarbonate solution includes supplying a diluted ammonium bicarbonate solution to an upper portion of a distillation unit, an upper portion of an ammonia condenser, and an upper portion of an absorber; distilling the diluted solution to discharge a first gas mixture, supplying the first gas mixture to a lower portion of the ammonium condenser; bringing the first gas mixture into contact with the diluted solution to be separated into a first mixed solution and a second gas mixture, supplying the first mixed solution to the upper portion of the absorber, and supplying the second gas mixture to a lower portion of the absorber; and bringing the second gas mixture into contact with the diluted solution supplied to the upper portion of the absorber and the first mixed solution supplied to the upper portion of the absorber to recover a concentrated ammonium bicarbonate solution.

Abstract: Disclosed is a vapor splitter including: a chimney tray dividing an internal space of a housing into an upper space and a lower space; a chimney provided on the chimney tray to enable the upper space and the lower space to communicate with each other; a cap covering the chimney with a gap therebetween such that a gas discharge hole is formed so that gas, coming out through the chimney, can be transferred to the upper space through the gas discharge hole; a liquid feeding unit for feeding liquid to the upper space; and a liquid discharging unit for discharging the liquid out of the upper space. The size of the gas discharge hole is adjusted by controlling the height of the liquid collected on the chimney. Further disclosed is a method of adjusting a vapor split ratio using the vapor splitter.

Abstract: A method of regenerating an ammonium bicarbonate solution includes supplying a diluted ammonium bicarbonate solution to an upper portion of a distillation unit, an upper portion of an ammonia condenser, and an upper portion of an absorber; distilling the diluted solution to discharge a first gas mixture, supplying the first gas mixture to a lower portion of the ammonium condenser; bringing the first gas mixture into contact with the diluted solution to be separated into a first mixed solution and a second gas mixture, supplying the first mixed solution to the upper portion of the absorber, and supplying the second gas mixture to a lower portion of the absorber; and bringing the second gas mixture into contact with the diluted solution supplied to the upper portion of the absorber and the first mixed solution supplied to the upper portion of the absorber to recover a concentrated ammonium bicarbonate solution.

Abstract: Disclosed is a vapor splitter including: a chimney tray dividing an internal space of a housing into an upper space and a lower space; a chimney provided on the chimney tray to enable the upper space and the lower space to communicate with each other; a cap covering the chimney with a gap therebetween such that a gas discharge hole is formed so that gas, coming out through the chimney, can be transferred to the upper space through the gas discharge hole; a liquid feeding unit for feeding liquid to the upper space; and a liquid discharging unit for discharging the liquid out of the upper space. The size of the gas discharge hole is adjusted by controlling the height of the liquid collected on the chimney. Further disclosed is a method of adjusting a vapor split ratio using the vapor splitter.

Abstract: Provided is a method of separating off reaction product water and recovering a carboxylic acid used as a solvent in a reactor from a reactor discharge during oxidation of an aromatic compound, and more particularly, a method of separating off reaction product water and recovering a carboxylic acid used as a solvent in a reactor from a reactor discharge during oxidation of an aromatic compound, wherein during the oxidation of the aromatic compound, the reactor discharge is led into two or more dehydration towers having different operating pressures such that a condenser of one dehydration tower operates as a reboiler of another dehydration tower, thereby remarkably reducing energy consumption.

Abstract: According to a method and an apparatus for regenerating an ammonium bicarbonate solution of the present invention, an evaporator, an absorber, and a concentrator, which can separate and concentrate an ammonium bicarbonate solution used as an osmotic solution, are arranged in the type of a tower, so it is possible to prevent precipitation of a salt in the process and continuously regenerate ammonium bicarbonate solution used as an osmotic solution.

Abstract: Provided is a method of separating off reaction product water and recovering a carboxylic acid used as a solvent in a reactor from a reactor discharge during oxidation of an aromatic compound, and more particularly, a method of separating off reaction product water and recovering a carboxylic acid used as a solvent in a reactor from a reactor discharge during oxidation of an aromatic compound, wherein during the oxidation of the aromatic compound, the reactor discharge is led into two or more dehydration towers having different operating pressures such that a condenser of one dehydration tower operates as a reboiler of another dehydration tower, thereby remarkably reducing energy consumption.

Abstract: A method of reducing or eliminating inflow of water to a dehydration tower using steam for separating water from a carboxylic acid from a reactor outlet gas produced in a reactor during oxidation of an aromatic compound in a carboxylic acid solvent to produce an aromatic acid, for example, oxidation of p-xylene in acetic acid solvent to produce terepthalic acid. The aromatic compound is introduced at the top of an absorption tower and collects ascending carboxylic acid solvent, introduced in the reactor outlet gas at the bottom of the absorption tower, for reintroduction into the reactor eliminating the need to remove and recover the solvent. The absorption tower, condensers and an organic-water separator remove the water in the reactor outlet gas as waste water, and the amount of water inflow to the dehydration tower is reduced or eliminated, as is the amount of steam required for separation.

Abstract: An apparatus and method for absorbing and recovering carbon dioxide from flue gas using ammonia water as an absorbent, including an absorption column and a circulation cooler connected to the absorption column so that a high-temperature absorbent is recovered from the absorption column, cooled to a preset temperature, and then supplied again into the absorption column, in order to dissipate absorptive heat generated when carbon dioxide is absorbed from the flue gas.

Abstract: The present invention relates to a method of reducing water from the reactor outlet gas in the oxidation process of an aromatic compound, for example, in the preparation of terephthalic acid by oxidation of xylene in an acetic acid solvent. As water is removed from the reactor outlet gas at the first absorption tower, the amount of water inflow to the dehydration tower is reduced and, thus, the amount of steam required to separate water and acetic acid at the dehydration tower is reduced and the load of the dehydration tower can be decreased. Further, by carefully controlling the flow amount of the reactor outlet gas to the first absorption tower, the operation of the dehydration tower may be made unnecessary.

Abstract: An apparatus and method for absorbing and recovering carbon dioxide from flue gas using ammonia water as an absorbent, including an absorption column and a circulation cooler connected to the absorption column so that a high-temperature absorbent is recovered from the absorption column, cooled to a preset temperature, and then supplied again into the absorption column, in order to dissipate absorptive heat generated when carbon dioxide is absorbed from the flue gas.