Ex parte JOHNSON et al. - Page 8


                  Appeal No. 1997-1551                                                                                                                       
                  Application No. 08/235,597                                                                                                                 

                                    The examiner indicates that Steag at p. 2, lines 4-13 sets forth a process for removing                                  
                                              SO2/SO3 out of a flue gas by initially passing the contaminated gas through a                                  
                                              dust collector followed by a dry cleaning of the gas to remove SO2/SO3.                                        


                                    After the dry cleaning, however, Steag captures the particles in a cloth filter (p. 2, lines                             
                                              75-83).                                                                                                        
                                    Steag does not teach the actual injection of dry sorbent particles into the flue gas stream                              
                                              after the particulate collection step.                                                                         
                                              Instead, the reference teaches a multiple stage filtration in which the dust content                           
                                                       is reduced from 10-15 g/m3 to 600 mg/ m3 in the first filtration, to 100-                             
                                                       200 mg/ m3 after the dry gas cleaning stage, and to 10 mg/ m3 in the final                            
                                                       filtration (p. 2, lines 55-83 and 105-115).5                                                          
                                              The reference does not explicitly discuss the dry gas cleaning process itself but                              
                                                       only indicates that such processes are Aknown per se@ at p. 2, line 15.                               
                                    Steag does not teach wet scrubbing in particular but only acknowledges the existence of                                  
                                              such processes in the prior art at p. 1, lines 60-65.                                                          
                           The examiner relies upon Peterson at p. 6A-9 to show dry sorbent particles of 10 microns in                                       
                                    size, which meets the greater than 1.0 micron limitation presently claimed.                                              
                           Although not specifically addressed in the Examiner=s Answer, Peterson shows the actual step                                      
                                    of ASorbent Injection@ into the flue gas stream for the purpose of removing SO3.  See                                    
                                    p. 6A-16, para. 1.  The dry sorbent is                                                                                   
                                                                                                                                                            
                  5 The A10 to 15 mg/ m3@ reported at p. 2, line 57, of Steag is an obvious typographical error.                                             

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