Methods and systems for purifying gases

Abstract

The present invention relates to methods and systems for purifying gases, such as for example semiconductor process gases. The invention more particularly relates to fluid purification methods and systems having improved heat transfer capabilities and controls such that the purified fluid produced from the process contains reduced impurity levels and/or exhibits more uniform concentrations within the final product. In another aspect of the invention, the activation time for adsorbent beds used in such processes and systems can be reduced.

What is claimed is: 
     
         1 . A process for purifying a fluid, the process comprising:
 feeding a process fluid containing at least one contaminant into an adsorption vessel, the adsorbent vessel having an inner surface and an outer surface, the vessel comprising at least one adsorbent bed formed of at least one adsorbent; at least one plate in thermal contact with the inner surface of the vessel and formed of material having higher thermal conductivity than the thermal conductivity of the at least one adsorbent; and wherein the at least one plate is configured to transfer heat and/or cooling to and from the at least one adsorbent bed;
 passing the process fluid over the at least one adsorption bed in the adsorption vessel such that the at least one contaminant is removed from the process fluid to form a purified process fluid; and 
 removing the purified process fluid from the adsorption vessel. 
   
     
     
         2 . The process of  claim 1 , wherein the process fluid comprises the at least one contaminant and arsine (AsH 3 ), phosphine (PH 3 ), ammonia (NH 3 ) or combinations thereof. 
     
     
         3 . The process of  claim 2 , wherein the process fluid is gaseous. 
     
     
         4 . The process of  claim 2 , wherein the at least one contaminant comprises moisture, CO 2 , SO 2  or combinations thereof. 
     
     
         5 . The process of  claim 4 , wherein the purified process fluid comprises arsine (AsH 3 ), phosphine (PH 3 ), ammonia (NH 3 ) or combinations thereof. 
     
     
         6 . The process of  claim 1 , wherein the number of plates is greater than 2. 
     
     
         7 . The process of  claim 1 , further comprising a heat transfer source positioned external to the outer surface of the vessel and configured to provide heat transfer to and from the vessel. 
     
     
         8 . The process of  claim 1 , wherein the adsorption vessel further includes at least one thermally conductive layer positioned in the adsorbent vessel such that the process fluid flows through the at least one adsorbent bed and the at least one thermally conductive layer. 
     
     
         9 . A process for activating at least one adsorption bed in an adsorption vessel, the activation process comprising:
 feeding an activation fluid into an adsorption vessel, the adsorbent vessel having an inner surface and an outer surface, the vessel comprising at least one adsorbent bed formed of at least one adsorbent; at least one plate in thermal contact with the inner surface of the vessel and formed of material having higher thermal conductivity than the thermal conductivity of the at least one adsorbent; and wherein the at least one plate is configured to transfer heat and/or cooling to and from the at least one adsorbent bed;   passing the activation fluid over the at least one adsorption bed in the adsorption vessel for a time sufficient for the at least one adsorption bed to heat up to an activation temperature;   maintaining the flow of the activation fluid through the at least one adsorption bed during an activation step, the activation step being for a time sufficient to activate the at least one adsorbent or for a time sufficient to regenerate the at least one adsorbent; and   cooling the at least one adsorption bed during a cooling step, the cooling step being for a time sufficient for the at least one adsorption bed to reach a predetermined cooled temperature.   
     
     
         10 . The activation process of  claim 9 , wherein the activation fluid is an inert gas. 
     
     
         11 . The activation process of  claim 10 , wherein the inert gas is selected from the group consisting of: nitrogen, hydrogen, helium, or argon. 
     
     
         12 . The activation process of  claim 9 , wherein the activation fluid is gaseous. 
     
     
         13 . The activation process of  claim 9 , wherein the activation fluid is removed from the adsorption vessel following the cooling step. 
     
     
         14 . The activation process of  claim 13 , wherein the activation fluid is an inert gas. 
     
     
         15 . The activation process of  claim 14 , wherein the activation fluid comprises nitrogen, hydrogen, helium, or argon. 
     
     
         16 . The activation process of  claim 9 , wherein the cooled temperature is an operating temperature or ambient temperature. 
     
     
         17 . The activation process of  claim 9 , wherein the number of plates is greater than 2. 
     
     
         18 . The activation process of  claim 9 , further comprising a heat transfer source positioned external