Once Through Steam Generator

Abstract

A once-through steam generator (OTSG) creating steam from feedwater by heat provided by flue gas. Combustion air is introduced into the OTSG through an air input/output apparatus. It is then fed into a combustion system to generate the flue gas. The flue gas is then fed into a steam generation apparatus to generate steam. The flue gas is returned to the air input/output apparatus to mix with and preheat the combustion air. Steam is created by the passing of the flue gas across a series of tube contained within the OTSG. The tubes are arranged in a combination counter-current/co-current configuration to provides for the minimization of the creation of solid deposits in the tubes.

1 . A once through steam generator (OTSG) for use in creating steam from feedwater, said OTSG comprising:
 an air input/output apparatus having an inlet/outlet to allow combustion air into said air input/output apparatus;   a combustion apparatus in communication with said air input/output apparatus to allow said combustion air access therein, said combustion apparatus having a combustion chamber to combust said combustion air to create flue gas; and   a steam generation apparatus having one or more tubes contained therein, said steam generation apparatus in communication with said combustion apparatus to allow said flue gas access therein and to heat said one or more tubes and in communication with said air input/output apparatus to allow flue gas to recirculate back into said air input/output apparatus and to mix with said combustion air, said each of said one or more tubes having an inlet and an outlet, wherein said feedwater enters inside each of said one or more tubes and is converted into steam by the heat differential caused by said flue gas and wherein said steam exits said one or more tubes through said outlet.   
     
     
         2 . The OTSG of  claim 1 , wherein said combustion apparatus comprising:
 a combustion air fan providing circulation to said combustion air;   a burner being configured to deliver fuel gas to mix with said combustion air mixes; and   a combustion chamber wherein said fuel gas/combustion air mixture combusts creating flue gas.   
     
     
         3 . The OTSG of  claim 1 , wherein said one or more tubes contained within said steam generator apparatus being further defined as follows:
 each of said one or more tubes having a combination counter-current/co-current configuration.   
     
     
         4 . The OTSG of  claim 1 , wherein said air input/output apparatus comprising:
 an inlet/outlet to allow combustion air into said air input/output apparatus;   a combustion air duct providing a passage way for said combustion air to access said combustion apparatus;   an air control damper between said inlet/outlet and said combustion air duct; and   flue gas recirculation control damper in communication with said inlet/outlet and said combustion air duct, said flue gas recirculation control damper to direct flue gas into said combustion air duct to mix, and preheat, combustion air or into said inlet/outlet to allow said flue gas to exit said OTSG.