NOVELTY - The apparatus comprises a gas supply unit, a water supply unit, a reactor (200) into which gas and water are respectively supplied from the gas supply unit and the water supply unit so that the gas and water react with each other in the reactor, a venturi valve connected to the gas supply unit through a first gas supply pipe, a pelletizer, and a cooling unit. The reactor comprises a dual cylinder unit (300) forming a gas hydrate in such a way as to squeeze a slurry of reaction water formed by the reaction between the gas and water, and cooling water paths that are formed in a housing.    USE - The apparatus is useful for producing and pelletizing gas hydrates, which are useful as energy sources for fossil fuels, in isolation/storage of carbon dioxide for the prevention of global warming and in desalination apparatus for separating gaseous or water solutions.    ADVANTAGE - The apparatus is capable of rapidly, efficiently and simply producing and pelletizing high-density gas hydrates in a continuous and consecutive manner with less power consumption and enhanced production rate and without any restrictions.    DETAILED DESCRIPTION - The apparatus comprises a gas supply unit, a water supply unit, a reactor (200) into which gas and water are respectively supplied from the gas supply unit and the water supply unit so that the gas and water react with each other in the reactor, a venturi valve connected to the gas supply unit through a first gas supply pipe, a pelletizer, and a cooling unit. The reactor comprises a dual cylinder unit (300) forming a gas hydrate in such a way as to squeeze a slurry of reaction water formed by the reaction between the gas and water, and cooling water paths that are formed in a housing of the reactor and communicate with the cooling unit. The dual cylinder unit of the reactor comprises an upper cylinder comprising an upper piston (314) and an upper cylinder casing, a lower cylinder comprising a lower piston (324) and a lower cylinder casing, a connection pipe (332) connecting the upper cylinder to the lower cylinder, an actuator connected to the upper cylinder and the lower cylinder to provide drive force to the upper and lower cylinders, a pipeline connecting the upper cylinder casing to the lower cylinder casing to guide flow of a incompressible fluid between the upper cylinder casing and the lower cylinder casing, and an extraction hole. The connection pipe has passing holes (335, 336) through which the reaction water in the reactor flows into and out of the connection pipe. A portion of the upper piston and a portion of the lower piston are placed in the upper and lower cylinder casings respectively. A movement of the upper and lower pistons is controlled by the flow of the incompressible fluid between the upper and lower cylinder casings through the pipeline. The pipeline comprises a first pipeline having a pair of flow path change valves, and a second pipeline connecting the pair of flow path change valves to each other. The actuator and the flow path change valves are electrically connected to a controller. The controller controls directions in which the flow path change valves are opened or closed such that a distance between the upper piston and the lower piston is maintained constant or changes. The slurry of the reaction water is drawn into the dual cylinder unit through the passing holes of the connection pipe by rotation of the reaction water, and is squeezed by a squeezing stroke of the upper and lower pistons. The lower cylinder of the dual cylinder unit comprises two sensors provided at different heights, where a height of the formed gas hydrate is controlled by adjusting the heights of the two sensors. The passing holes of the connection pipe comprise a first passing hole and a second passing hole. The first passing hole is positioned above the second passing hole, and is larger than the second passing hole. The venturi valve is connected to the water supply unit through a water supply pipe, and is connected to the reactor through a mixture supply pipe and a second gas supply pipe. Gas supplied from the gas supply unit through the gas supply pipe is mixed with water supplied from the water supply unit through the water supply pipe by the venturi valve. A mixture of the gas and the water is supplied into the reactor through the mixture supply pipe. The pelletizer extracts the formed gas hydrate out of the dual cylinder unit, and is operated when the gas hydrate formed in the dual cylinder unit is disposed at a position corresponding to the extraction hole. An INDEPENDENT CLAIM is included for a method of consecutively producing and pelletizing gas hydrates.    DESCRIPTION OF DRAWING(S) - The diagram shows an exploded perspective view of a reactor of an apparatus for producing and pelletizing gas hydrates.    Reactor (200)    Dual cylinder unit (300)    Upper piston (314)    Lower piston (324)    Connection pipe (332)    Passing holes. (335, 336)