Method for nitrogen prefill of high pressure oxygen-containing gas line for gasification

Abstract

The present invention provides a much safer solution to pressurizing oxygen-containing gas feed lines at the start up of an oxygen-containing gas using process unit. All piping downstream of the main oxygen-containing gas block valve is pressurized with inert nitrogen prior to introducing the oxygen-containing gas into the piping. By equalizing with nitrogen it removes the hazard of slowly pressurizing the piping with the oxygen-containing gas and exposing the oxygen-containing gas to the substantial pressure drop associated with pressurizing piping to a high pressure.

What is claimed is:  
     
         1 . A method for reducing frictional combustion in an oxygen-containing gas line, the method comprising: 
 purging the oxygen-containing gas line with an inert gas;    pressurizing the oxygen-containing gas line with the inert gas to a pressure equivalent to the pressure of the oxygen-containing gas being introduced; and    introducing oxygen-containing gas into said oxygen-containing gas line.    
     
     
         2 . The method of  claim 1 , wherein the inert gas is nitrogen.  
     
     
         3 . The method of  claim 1 , wherein the pressurized oxygen-containing gas line is an oxygen-containing gas feed line to a gasification reactor.  
     
     
         4 . The method of  claim 1 , wherein the oxygen-containing gas is selected from the group consisting of air, enriched air, and pure oxygen.  
     
     
         5 . The method of  claim 1 , wherein the pressurized oxygen-containing gas line comprises a oxygen-containing gas block valve upstream of an oxygen-containing gas control valve, the oxygen-containing gas control valve being upstream of an oxygen-containing gas using process unit.  
     
     
         6 . The method of  claim 5 , wherein the oxygen-containing gas using process unit is a gasification reactor.  
     
     
         7 . The method of  claim 5 , wherein the oxygen-containing gas line is pressurized with the inert gas between the oxygen-containing gas control valve and the oxygen-containing gas using process unit.  
     
     
         8 . The method of  claim 6 , wherein the oxygen-containing gas control valve is opened so as to pressurize a section of the oxygen-containing gas line between the oxygen-containing gas block valve and the oxygen containing gas control valve.  
     
     
         9 . The method of  claim 8 , wherein the introduction of the oxygen-containing gas into said oxygen-containing gas line is accomplished by opening an oxygen-containing gas equalization valve that bypasses the oxygen-containing gas block valve.  
     
     
         10 . The process of  claim 1 , further comprising using a plurality of interlocks to control the pressurizing of the oxygen-containing gas line with the inert gas.  
     
     
         11 . The process of  claim 10 , wherein one of said interlocks verifies that the purging the oxygen-containing gas line with an inert gas is complete.  
     
     
         12 . The process of  claim 10 , wherein one of said interlocks verifies that the inert gas pressure is adequate to gas to the pressure the oxygen-containing gas line to a pressure equivalent to that of the oxygen-containing gas being introduced.  
     
     
         13 . The process of  claim 10 , wherein one of said interlocks verifies that the oxygen-containing gas line is isolated.  
     
     
         14 . The process of  claim 10 , wherein one of said interlocks verifies that the pressure of the source of the oxygen-containing gas is at a sufficient pressure so that after the oxygen-containing gas line is pressurized with the inert gas and the oxygen-containing gas is introduced into the oxygen-containing gas line, the inert gas will not flow back into the source of the oxygen-containing gas.  
     
     
         15 . A method for placing an oxygen-containing gas feed line to a gasification reactor in service, the method comprising: 
 purging the oxygen-containing gas feed line with an inert gas;    pressurizing the oxygen-containing gas feed line with the inert gas to a pressure equivalent to the pressure of oxygen-containing gas being introduced; and    introducing the oxygen-containing gas into the oxygen-containing gas line.    
     
     
         16 . The method of  claim 15 , wherein the inert gas is nitrogen.  
     
     
         17 . The method of  claim 15 , wherein the oxygen-containing gas is selected from the group consisting of air, enriched air, and pure oxygen.  
     
     
         18 . The process of  claim 15 , further comprising using a plurality of interlocks to control the pressurizing of the oxygen-containing gas feed line with the inert gas.  
     
     
         19 . The process of  claim 18 , wherein one of said interlocks verifies that the purging the oxygen-containing gas feed line with an inert gas is complete.  
     
     
         20 . The process of  claim 18 , wherein one of said interlocks verifies that the inert gas pressure is adequate to gas to the pressure the oxygen-containing gas feed line to a pressure equivalent to that of the oxygen-containing gas being introduced.  
     
     
         21 . The process of  claim 18 , wherein one of said interlocks verifies that the oxygen-containing gas feed line is isolated.  
     
     
         22 . The process of  claim 18 , wherein one of said interlocks verifies that the pressure of the source of the oxygen-containing gas is at a sufficient pressure so that after the oxygen-containing gas feed line is pressurized with the inert gas and the oxygen-containing gas is introduced into the oxygen-containing gas feed line, the inert gas will not flow back into the source of the oxygen-containing gas.