Patent ID: 6050106
Filing Date: 2000-04-18
Classification: F25J

Abstract:
An ultra high purity nitrogen and oxygen generator unit, which comprises:a first rectification column having, in order from above, a first upper space part, an upper rectifying part, a middle rectifying part, a lower rectifying part and a first lower space part;a second rectification column having a second upper space part, a rectifying part and a second lower space part;a main heat exchanger for cooling down air as a feed material through an indirect heat exchange with a refrigerant, and supplying the thus-cooled air to below said lower rectifying part;a nitrogen condenser for cooling down high purity nitrogen gas collected in the first upper space part, which is introduced therein, and supplying the thus-condensed high purity liquid nitrogen to above the upper rectifying part as a reflux liquid and discharging the non-condensed gas out of the system;a high purity liquid nitrogen supply pipe for supplying high purity liquid nitrogen as a portion of the reflux liquid to above said upper rectifying part;a first expansion valve for reducing the pressure of oxygen-rich liquid air collected in the first lower space part, which is introduced therein, and supplying the thus-generated oxygen-rich waste gas to the nitrogen condenser as a refrigerant;a second expansion valve for reducing the pressure of a portion of the reflux liquid which is extracted from between the middle rectifying part and the lower rectifying part, and causing said portion of the reflux liquid reduced in pressure to join with said oxygen-rich waste gas downstream of said first expansion valve;an oxygen-rich waste gas pipe for supplying the oxygen-rich waste gas which has been used as a refrigerant in the nitrogen condenser and discharged therefrom to said main heat exchanger as a refrigerant;an ultra high purity nitrogen delivery pipe for recovering a portion of the reflux liquid from between the upper rectifying part and the middle rectifying part as ultra high purity liquid nitrogen;a third expansion valve for reducing the pressure of a portion of the reflux liquid which is extracted from between the middle rectifying part and the lower rectifying part, and supplying the thus-generated gas-liquid mixture to above the rectifying part of the second rectification column;a reboiler placed in the second lower space part for heating liquid collected in the second lower space part to evaporate a portion thereof;a waste gas pipe for discharging gas collected in the second upper space part out of the system; andan ultra high purity oxygen delivery pipe for recovering liquid collected in the second lower space part as ultra high purity liquid oxygen.