Method of controlling drum temperature transients

Abstract

An evaporator system comprises an evaporator; a drum; and a pump that are in fluid communication with each other. The pump is operative to create a temporary pressure gradient during start-up of an evaporator system and transport a fluid from the evaporator to the drum prior to the fluid reaching its boiling point in the evaporator. Following the fluid reaching its boiling point in the evaporator, the fluid naturally circulates in the evaporator system.

1 . A method comprising:
 creating a temporary pressure gradient during start-up of an evaporator system, where the evaporator system comprises:
 an evaporator; 
 a drum; and 
 a pump; where the evaporator, the drum and the pump are in fluid communication with each other; 
   transporting a fluid from the evaporator to the drum prior to the fluid reaching its boiling point in the evaporator; and   circulating the fluid through the evaporator system via natural circulation after the fluid has reached its boiling point in the evaporator.   
     
     
         2 . The method of  claim 1 , where the pump is a centrifugal pump or a jet pump. 
     
     
         3 . The method of  claim 1 , where the fluid is water. 
     
     
         4 . The method of  claim 1 , where the fluid is steam. 
     
     
         5 . The method of  claim 1 , where the evaporator system further comprises valves for isolating the pump from the evaporator system. 
     
     
         6 . The method of  claim 1 , where the evaporator system further comprises a downcomer; the pressure gradient being created in the downcomer from a region of lower pressure in the steam drum to a region of higher pressure in the evaporator. 
     
     
         7 . The method of  claim 1 , where the pump is downstream of the steam drum and upstream of the evaporator. 
     
     
         8 . The method of  claim 2 , where the jet pump is downstream of the steam drum and in fluid communication with a downcomer that is in fluid communication with the steam drum.