Method and device for producing a gaseous pressurized oxygen product by cryogenic separation of air

Abstract

Process and apparatus for producing a pressurized gaseous oxygen product by cryogenic air separation The process and the apparatus serve for producing a pressurized gaseous oxygen product by cryogenic air separation in a distillation column system which has at least one separating column. Feed air is compressed in an air compressor. A first partial stream ( 2, 4, 6, 7 ) of the compressed feed air is expanded ( 5, 8 ) while performing work. A second partial stream ( 3 ) of the compressed feed air ( 1 ) is cooled and liquefied or pseudo-liquefied and subsequently introduced into the distillation column system. A liquid oxygen product stream ( 51 ) is removed from the distillation column system, brought to a first increased pressure in the liquid state ( 52 ), vaporized or pseudo-vaporized under this first increased pressure by indirect heat exchange ( 10 ) with the second partial stream ( 3 ) of the compressed feed air, warmed to approximately ambient temperature ( 10 ) and finally drawn off as a gaseous product stream ( 55 ). The vaporized or pseudo-vaporized oxygen product stream ( 53 ) is brought further to a second increased pressure, which is higher than the first increased pressure, in a cold compressor ( 13 ). The product stream ( 54 ) is warmed to approximately ambient temperature under this second increased pressure ( 10 ). At least part of the mechanical energy produced in the work-performing expansion ( 5, 8 ) of the first partial stream ( 3 ) is used for driving the cold compressor ( 13 ).

1 . A process for producing a pressurized gaseous oxygen product by cryogenic air separation in a distillation column system which has at least one separating column, in which process
 feed air is compressed in an air compressor,   a first partial stream ( 2 ,  4 ,  6 ,  7 ) of the compressed feed air is expanded ( 5 ,  8 ) while performing work,   a second partial stream ( 3 ) of the compressed feed air ( 1 ) is cooled and liquefied or pseudo-liquefied and subsequently introduced into the distillation column system,   a liquid oxygen product stream ( 51 ) is removed from the distillation column system, brought to a first increased pressure ( 52 ) in the liquid state, vaporized or pseudo-vaporized under this first increased pressure by indirect heat exchange ( 10 ) with the second partial stream ( 3 ) of the compressed feed air, warmed to approximately ambient temperature ( 10 ) and finally drawn off as a gaseous product stream ( 55 ), characterized in that   the vaporized or pseudo-vaporized oxygen product stream ( 53 ) is brought further to a second increased pressure, which is higher than the first increased pressure, in a cold compressor ( 13 ) and   the product stream ( 54 ) under this second increased pressure is warmed to approximately ambient temperature ( 10 ), wherein   at least part of the mechanical energy produced in the work-performing expansion ( 5 ,  8 ) of the first partial stream ( 3 ) is used for driving the cold compressor ( 13 ).   
     
     
         2 . The process as claimed in  claim 1 , characterized in that the work-performing expansion of the first partial stream ( 2 ,  4 ,  6 ,  7 ) is carried out in two expanders ( 5 ,  8 ) connected in parallel or in series. 
     
     
         3 . The process as claimed in  claim 2 , characterized in that the first partial stream ( 6 ) is warmed between the two expanders connected in series ( 10 ). 
     
     
         4 . The process as claimed in  claim 2 , characterized in that the two expanders connected in parallel have the same inlet temperature and/or the same inlet pressure. 
     
     
         5 . The process as claimed in  claim 4 , characterized in that the two expanders connected in parallel have the same outlet pressure and/or the same outlet temperature. 
     
     
         6 . The process as claimed in  claim 2 , characterized in that mechanical energy of both expanders ( 5 ,  8 ) is used for driving the cold compressor ( 13 ). 
     
     
         7 . The process as claimed in  claim 1 , characterized in that the cooling of the feed air, the liquefaction or pseudo-liquefaction of the second partial stream, the vaporization or pseudo-vaporization of the product stream and the warming of the product stream are carried out in a main heat exchanger. 
     
     
         8 . An apparatus for producing a pressurized gaseous oxygen product by cryogenic air separation
 with a distillation column system which has at least one separating column,   with an air compressor for compressing feed air,   with a first expander for the work-performing expansion ( 5 ,  8 ) of a first partial stream ( 2 ,  4 ,  6 ,  7 ) of the compressed feed air,   with means for cooling and liquefying or pseudo-liquefying a second partial stream ( 3 ) of the compressed feed air ( 1 ),   with means for introducing the liquefied or pseudo-liquefied first partial stream into the distillation column system,   with means for removing a liquid oxygen product stream ( 51 ) from the distillation column system, bringing it to a first increased pressure ( 52 ) in the liquid state, vaporizing or pseudo-vaporizing it under this first increased pressure by indirect heat exchange ( 10 ) with the second partial stream ( 3 ) of the compressed feed air, warming it to approximately ambient temperature ( 10 ) and finally drawing it off as a gaseous product stream ( 55 ), characterized by   a cold compressor ( 13 ) for further increasing the pressure of the vaporized or pseudo-vaporized oxygen product stream ( 53 ) to a second increased pressure, which is higher than the first increased pressure, by   means for warming ( 10 ) the product stream ( 54 ) under this second increased pressure to approximately ambient temperature and by   means for transmitting at least part of the mechanical energy produced in the work-performing expansion ( 5 ,  8 ) of the first partial stream ( 3 ) to the cold compressor ( 13 ).   
     
     
         9 . The apparatus as claimed in  claim 8 , characterized by a second expander ( 8 ) for the work-performing expansion of the first partial stream ( 2 ,  4 ,  6 ,  7 ), which is connected to the first expander ( 5 ) in parallel or in series. 
     
     
         10 . The apparatus as claimed in  claim 8 , characterized by means for warming ( 10 ) the first partial stream ( 6 ) between the two expanders connected in series. 
     
     
         11 . The apparatus as claimed in  claim 8 , characterized in that the two expanders connected in parallel have the same inlet temperature, the same inlet pressure, the same outlet pressure and/or the same outlet temperature. 
     
     
         12 . The apparatus as claimed in  claim 8 , characterized by means for transmitting mechanical energy from both expanders ( 5 ,  8 ) to the cold compressor ( 13 ). 
     
     
         13 . The apparatus as claimed in  claim 8 , characterized in that the cooling of the feed air, the liquefaction or pseudo-liquefaction of the second partial stream, the vaporization or pseudo-vaporization of the product stream and the warming of the product stream are carried out in a main heat exchanger.