Process and system for obtaining a gaseous pressure product by the cryogenic separation of air

Abstract

A process and system are used for obtaining a gaseous pressure product by cryogenic separation of air. In the normal operation, charge air is condensed, cooled and fed to a distillation column system; a product fraction is withdrawn-in a liquid condition from the distillation column system, and is introduced into a liquid tank; product liquid is removed from the liquid tank, is pressurized in a pump set in the liquid condition to an increased pressure, is evaporated in an indirect heat exchange with a first heat transfer medium flow, and is withdrawn as a gaseous pressure product. In an emergency operation, product liquid is removed from the liquid tank, is brought in the liquid condition to an increased pressure, is evaporated in an indirect heat exchange with a second heat transfer medium flow, and is withdrawn as a gaseous pressure product. In a bypass operation, the product fraction withdrawn in the liquid condition from the distillation column system is guided past the liquid tank; is brought via the pump set is brought in the liquid condition to an increased pressure; is evaporated in an indirect heat exchange, and is withdrawn as a gaseous pressure product.

1 . Process for obtaining a gaseous pressure product by cryogenic separation of air, 
 wherein, in a normal operation: 
 charge air is condensed, cooled and fed to a distillation column system,  
 a product fraction is withdrawn in a liquid state from the distillation column system and is introduced into a liquid tank,  
 product liquid is removed from the liquid tank, via a pump set having one or more parallel-connected individual pumps, is brought in the liquid condition to an increased pressure, is evaporated in an indirect heat exchange with a first heat transfer medium flow, and is withdrawn as a gaseous pressure product,  
 wherein, in an emergency operation:  
 product liquid is removed from the liquid tank, is brought in the liquid condition to an increased pressure, is evaporated in an indirect heat exchange with a second heat transfer medium flow and is withdrawn as a gaseous pressure product, and  
 wherein in a bypass operation:  
 the product fraction withdrawn in a liquid state from the distillation column system is guided past the liquid tank, is pressurized in the pump set in the liquid condition to an increased pressure, is evaporated in an indirect heat exchange, and is withdrawn as a gaseous pressure product.  
   
   
   
       2 . Method according to  claim 1 , wherein at least one individual pump of the pump set has a first pump bypass, by way of which, in the normal operation, at least at times, a portion of the product liquid exiting from the pump is expanded and is returned into the liquid tank, and wherein at least one individual pump, in addition to the first pump bypass, has a second pump bypass, by way of which, in the bypass operation, at least at times, a portion of the product liquid exiting from the pump is expanded, is guided past the liquid tank, and is returned into the distillation column system.  
   
   
       3 . Process according to  claim 1 , wherein the distillation column system is constructed with two or more branches, the product fraction being introduced from the two or more branches of the distillation column system into the liquid tank.  
   
   
       4 . Process according to  claim 2 , wherein the distillation column system is constructed with two or more branches, the product fraction being introduced from the two or more branches of the distillation column system into the liquid tank.  
   
   
       5 . System for obtaining a gaseous pressure product by cryogenic separation of air having a distillation column system, a liquid tank, a pump set having one or more parallel-connected individual pumps, a main heat exchanger and an emergency supply heat exchanger, and a regulating device which regulates the operation of the system in a normal operation and in an emergency operation, wherein, 
 in the normal operation:    charge air is condensed, cooled and fed to the distillation column system,    a product fraction is withdrawn in a liquid state from the distillation column system and is introduced into the liquid tank,    product liquid is removed from the liquid tank via the pump set, is brought in the liquid condition to an increased pressure, is evaporated in the indirect heat exchange with a first heat transfer medium flow in the main heat exchanger, and is withdrawn as a gaseous pressure product,    and in the emergency operation:    product liquid is removed from the liquid tank, is brought in the liquid condition to an increased pressure via the pump set, is evaporated in an indirect heat exchange with a second heat transfer medium flow in the emergency supply heat exchanger and is withdrawn as a gaseous pressure product, and    wherein in addition, the regulating device regulates the operation of the system in a bypass operation such that, in the bypass operation:    the product fraction withdrawn in a liquid state from the distillation column system is guided past the liquid tank, is brought in the liquid condition to an increased pressure, is evaporated in an indirect heat exchange, and is withdrawn as a gaseous pressure product.    
   
   
       6 . A system according to  claim 5 , wherein at least one individual pump of the pump set has a first pump bypass, by way of which, in the normal operation, at least at times, a portion of the product liquid exiting from the pump is expanded and is returned into the liquid tank, and wherein at least one individual pump, in addition to the first pump bypass, has a second pump bypass, by way of which, in the bypass operation, at least at times, a portion of the product liquid exiting from the pump is expanded, is guided past the liquid tank, and is returned into the distillation column system.  
   
   
       7 . A system according to  claim 5 , wherein the distillation column system is constructed with two or more branches, the product fraction being introduced from the two or more branches of the distillation column system into the liquid tank.  
   
   
       8 . A system according to  claim 6 , wherein the distillation column system is constructed with two or more branches, the product fraction being introduced from the two or more branches of the distillation column system into the liquid tank.