Process and appratus for producing gas hydrate

Abstract

A process is provided which includes: bringing a natural gas, e.g., methane gas or propane gas, or a mixture of these gases into gas-liquid contact with raw-material water to form a gas hydrate; compression-molding the gas hydrate into pellets; and cooling/depressurizing the pellets. Also provided is an apparatus for use in the process. In the cooling/depressurizing step 4, molded gas hydrate masses h 3 in a pressurized state are cooled and depressurized to a downstream-side pressure. In the cooling/depressurizing step 4, a receiving chamber 15 which accommodates the gas hydrate masses h 3 obtained in the molding step 3 is provided, and the masses h 3 are depressurized to the downstream-side pressure while passing through the receiving chamber 15 . The masses h 3 are introduced into and immersed in a liquid refrigerant r packed in the receiving chamber 15 so that the masses h 3 are cooled by solid/liquid contacting with the liquid refrigerant r.

1 . A process for producing a gas hydrate characterized by comprising:
 a cooling/depressurizing step of cooling a molded gas hydrate mass in a pressurized state and depressurizing the molded gas hydrate mass to a downstream-side pressure, the process characterized in that   in the cooling/depressurizing step, a receiving chamber which accommodates the gas hydrate mass is provided, and the mass is depressurized to the downstream-side pressure while passing through the receiving chamber, and   the mass is immersed in a liquid refrigerant packed in the receiving chamber, so that the mass is cooled by solid/liquid contacting with the liquid refrigerant.   
     
     
         2 . A process for producing a gas hydrate characterized by comprising:
 a cooling/depressurizing step of cooling a molded gas hydrate mass in a pressurized state and depressurizing the molded gas hydrate mass to a downstream-side pressure; and   a solid/liquid separating step of separating a refrigerant from the gas hydrate mass, the refrigerant accompanying the gas hydrate mass cooled and depressurized in the cooling/depressurizing step,   the process characterized in that   in the cooling/depressurizing step, a receiving chamber which accommodates the gas hydrate mass obtained in the molding step is provided, the mass is depressurized to the downstream-side pressure while passing through the receiving chamber, and the mass is immersed in a liquid refrigerant packed in the receiving chamber, so that the mass is cooled by solid/liquid contacting with the liquid refrigerant, and   in the solid/liquid separating step, the cooled and depressurized gas hydrate mass is separated from the liquid refrigerant, and the gas hydrate mass is cooled by evaporation heat generated when the liquid refrigerant still attached to the gas hydrate mass evaporates.   
     
     
         3 . An apparatus for producing a gas hydrate characterized by comprising:
 a cooling/depressurizing device for cooling a molded gas hydrate mass in a pressurized state and depressurizing the molded gas hydrate mass to a downstream-side pressure, the apparatus characterized in that   the cooling/depressurizing device includes:
 an introduction port for the gas hydrate mass; 
 a supply port for a liquid refrigerant; 
 a discharge port for discharging the gas hydrate mass together with the refrigerant; and 
 a receiving chamber formed to be communicatable with any of the introduction port, the refrigerant supply port, and the discharge port, 
   the liquid refrigerant at any one of a pressure on a molding device side and an approximate pressure thereto is supplied and packed into the receiving chamber from the refrigerant supply port,   the gas hydrate mass is immersed through the introduction port in the liquid refrigerant in the receiving chamber, and   the liquid refrigerant and the gas hydrate mass are discharged from the discharge port communicating with the downstream-side pressure.   
     
     
         4 . An apparatus for producing a gas hydrate characterized by comprising:
 a cooling/depressurizing device for cooling a molded gas hydrate mass in a pressurized state and depressurizing the molded gas hydrate mass to a downstream-side pressure; and   a solid/liquid separating device for separating a refrigerant from the gas hydrate mass, the refrigerant accompanying the gas hydrate mass cooled and depressurized by the cooling/depressurizing device,   the apparatus characterized in that   the cooling/depressurizing device includes:
 an introduction port for the gas hydrate mass; 
 a supply port for a liquid refrigerant; 
 a discharge port for discharging the gas hydrate mass together with the refrigerant; and 
 a receiving chamber formed to be communicatable with any of the introduction port, the refrigerant supply port, and the discharge port, in which 
 the liquid refrigerant at any one of a pressure on a molding device side and an approximate pressure thereto is supplied and packed into the receiving chamber from the refrigerant supply port, 
 the gas hydrate mass is immersed through the introduction port in the liquid refrigerant in the receiving chamber, and 
 the liquid refrigerant and the gas hydrate mass are discharged from the discharge port communicating with the downstream-side pressure, and 
   in the solid/liquid separating device, a liquid separating chamber is formed to separate the gas hydrate mass and the liquid refrigerant which are discharged from the cooling/depressurizing device, and to evaporate the liquid refrigerant still attached to the gas hydrate mass.