Method and apparatus for producing nitrogen oxide gas

Abstract

The method for producing dinitrogen tetraoxide comprising the steps of operating a decompressor ( 3 ) to reduce a pressure within the space area ( 2 ) maintained in the hermetically sealed condition to the decompressed or vacuum condition below the saturated vapor pressure curve of dinitrogen tetraoxide, supplying the dinitrogen tetraoxide liquid as a sterilant feedstock from a vessel ( 4 ) to a spray device ( 25 ) while preventing gasification of the dinitrogen tetraoxide liquid on the way between the vessel ( 4 ) and spray device ( 25 ), and spraying the dinitrogen tetraoxide liquid through the spray device ( 25 ) into the space area ( 2 ) under the decompressed or vacuum condition to, at the time of the spraying, gasify at least some of the dinitrogen tetraoxide liquid within the space area ( 2 ) decompressed below the saturated vapor pressure curve.

What is claimed is: 
     
         1 . A method for producing a dinitrogen tetraoxide gas, comprising the steps of
 maintaining a space area in the hermetically sealed condition, the space area being connected to a dinitrogen tetraoxide liquid in a vessel as a feedstock of dinitrogen tetraoxide gas,   reducing an inner pressure of the space area to a decompressed or vacuum condition below the saturated vapor pressure curve of dinitrogen tetraoxide by operating a decompressor communicated to the space area,   supplying the dinitrogen tetraoxide liquid from the vessel to the spray device while retaining the liquid condition of the dinitrogen tetraoxide on the way between the vessel and spray device, and   spraying the dinitrogen tetraoxide liquid through the spray device into the space area under the decompressed or vacuum condition to gasify at least some of the sprayed dinitrogen tetraoxide liquid across the saturated vapor pressure curve in the space area.   
     
     
         2 . The method of  claim 1 , wherein the dinitrogen tetraoxide liquid is supplied from the vessel through the spray device into the space area while preventing the gasification of the supplied dinitrogen tetraoxide liquid. 
     
     
         3 . The method of  claim 1 , further comprising allowing the sprayed dinitrogen tetraoxide to come into contact to an object in the space area to oxidize or nitrate the object. 
     
     
         4 . The method of  claim 1 , further comprising heating with a heater the dinitrogen tetraoxide liquid between the vessel and spray device before spraying the dinitrogen tetraoxide liquid. 
     
     
         5 . The method of  claim 1 , further comprising introducing a diluent gas into the space area before, after or at the same time of spraying the dinitrogen tetraoxide liquid into the space area. 
     
     
         6 . The method of  claim 5 , wherein the diluent gas is selected from one or more groups consisting of water vapor, oxygen, nitrogen, air and inert gas. 
     
     
         7 . The method of  claim 1 , further comprising atomizing the nitrogen oxide liquid into nitrogen oxide gas in the space area at the time of spraying the dinitrogen tetraoxide liquid. 
     
     
         8 . The method of  claim 1 , further comprising:
 opening a control valve provided at a feed pipe for connecting the vessel and spray device, the vessel being made up of a bomb or tank that contains a necessary amount of the dinitrogen tetraoxide liquid, and   supplying a full amount of the dinitrogen tetraoxide liquid from the bomb or tank through the feed pipe to the spray device.   
     
     
         9 . The method of  claim 3 , further comprising sucking and collecting the dinitrogen tetraoxide gas through an outlet of the space area after oxidization or nitration of the object, and
 cooling and condensing the collected dinitrogen tetraoxide gas into liquid.   
     
     
         10 . The method of  claim 3 , further comprising:
 applying the inner pressure on or cooling the inner temperature of the space area across the saturated vapor pressure curve of dinitrogen tetraoxide to condense the dinitrogen tetraoxide gas into liquid in the space area,   collecting the condensed dinitrogen tetraoxide liquid through an outlet of the space area, and   removing the object out of the space area.   
     
     
         11 . An apparatus for producing dinitrogen tetraoxide, comprising:
 a vessel for storing dinitrogen tetraoxide liquid as a feedstock of dinitrogen tetraoxide gas,   a space area that may be maintained in a hermetically sealed condition,   a spray device provided at the space area for connection to the vessel,   a decompressor for reducing an inner pressure of the space area to a decompressed or vacuum condition below the saturated vapor pressure curve of dinitrogen tetraoxide,   a feed pipe for connecting the vessel and spray device, and   a control valve provided in the feed pipe to supply the dinitrogen tetraoxide liquid from the vessel to the spray device while retaining the liquid condition of the dinitrogen tetraoxide in the feed pipe when the control valve is opened, and to spray the dinitrogen tetraoxide liquid through the spray device into the space area while gasifying at least some of the dinitrogen tetraoxide liquid in the space area retained at the decompressed condition below the saturated vapor pressure curve of dinitrogen tetraoxide.   
     
     
         12 . The apparatus of  claim 11 , wherein the dinitrogen tetraoxide liquid is prevented from the gasification on the way from the vessel to the spray device. 
     
     
         13 . The apparatus of  claim 11 , wherein the dinitrogen tetraoxide gas comes into contact to an object arranged in the space area for oxidization or nitration of the object. 
     
     
         14 . The apparatus of  claim 11 , further comprising a heater for heating the dinitrogen tetraoxide liquid in the feed pipe before spraying the heated dinitrogen tetraoxide through the spray device into the space area. 
     
     
         15 . The apparatus of  claim 11 , wherein the spray device atomizes at least some of the sprayed nitrogen oxide liquid into gas in the space area. 
     
     
         16 . The apparatus of  claim 11 , wherein the vessel comprises a bomb or tank for storing a necessary amount of the dinitrogen tetraoxide liquid to supply the full amount of the dinitrogen tetraoxide liquid from the bomb or tank through the feed pipe to the spray device when the control valve is opened. 
     
     
         17 . The apparatus of  claim 11 , wherein the space area has an outlet connected to the decompressor through a cooler for cooling and condensing into liquid the dinitrogen tetraoxide gas to remove the condensed liquid by operation of the decompressor. 
     
     
         18 . The apparatus of  claim 13 , further comprising:
 a pressure controller for increasing the inner pressure of the space area to condense the dinitrogen tetraoxide gas into liquid after the oxidization or nitration of the object, and   an outlet provided at the bottom of the space area to remove the condensed dinitrogen tetraoxide liquid outside the space area.   
     
     
         19 . The apparatus of  claim 13 , further comprising:
 a thermal controller for lowering the inner temperature of the space area to condense the dinitrogen tetraoxide into liquid within the space area after the oxidization or nitration of the object, and   an outlet provided at the bottom of the space area to remove the condensed dinitrogen tetraoxide liquid through the thermal controller.