Continuous Evaporator

Abstract

A continuous evaporator for a horizontally constructed waste heat steam generator is provided. The continuous evaporator includes a first evaporator heating surface having a plurality of essentially vertically arranged first steam generator tubes through which a flow medium can flow from bottom to top, and a second evaporator heating surface which is mounted downstream of the first evaporator heating surface on the flow medium side. The second evaporator heating surface includes a plurality of additional essentially vertically arranged second steam generator tubes through which a flow medium can flow from bottom to top. The second steam generator tubes are designed in such a manner that the average mass flow density which can be controlled in the full load operation does not fall below a predetermined minimum mass flow density in the second steam generator tubes.

1 .- 10 . (canceled) 
     
     
         11 . A method for designing a continuous evaporator for a horizontally constructed waste heat steam generator, comprising:
 providing a first evaporator heating surface which incorporates a plurality of first steam generation tubes, a first arrangement of which is essentially vertical and through which a flow is from the bottom to the top;   providing a second evaporator heating surface which incorporates a plurality of second steam generation tubes a second arrangement of which is essentially vertical and through which the flow is from the bottom to the top; and   connecting the second evaporator heating surface downstream from the first evaporator heating surface on a flow substance side,   wherein a minimum mass flow density is prescribed, and   wherein a mean mass flow density established in the plurality of second steam generation tubes when operating at full load does not fall below the prescribed minimum mass flow density.   
     
     
         12 . The method as claimed in  claim 11 , wherein the prescribed minimum mass flow density is 180 kg/m 2  s. 
     
     
         13 . The method as claimed in  claim 11 , wherein an internal diameter of the plurality of second steam generation tubes is chosen such that the mean mass flow density which is established in the plurality of second steam generation tubes when operating at full load does not fall below the prescribed minimum mass flow density. 
     
     
         14 . The method as claimed in  claim 13 , wherein the internal diameter of the plurality of second steam generation tubes is not less than a minimum diameter determined on the basis of prescribed operating parameters. 
     
     
         15 . The method as claimed in  claim 13 , wherein the internal diameter of the plurality of second steam generation tubes includes a value between 20 and 40 mm. 
     
     
         16 . The method as claimed in  claim 11 , wherein the plurality of second steam generation tubes are connected one after another on a heating gas side as rows of tubes. 
     
     
         17 . A continuous evaporator, comprising:
 a first evaporator heating surface incorporating a plurality of first steam generation tubes; and   a second evaporator heating surface incorporating a plurality of second steam generation tubes,   wherein an arrangement of the plurality of first steam generation tubes and the plurality of second generation tubes is essentially vertical and through which a flow is from the bottom to the top,   wherein the first evaporator heating surface is connected downstream from the second evaporator heating surface on a heating gas side,   wherein a minimum mass flow density is prescribed, and   wherein a mean mass flow density established in the plurality of second steam generation tubes when operating at full load does not fall below the prescribed minimum mass flow density.   
     
     
         18 . The continuous evaporator as claimed in  claim 17 , wherein the prescribed minimum mass flow density is 180 kg/m 2  s. 
     
     
         19 . The continuous evaporator as claimed in  claim 17 , wherein an internal diameter of the plurality of second steam generation tubes is chosen such that the mean mass flow density which is established in the plurality of second steam generation tubes when operating at full load does not fall below the prescribed minimum mass flow density. 
     
     
         20 . The continuous evaporator as claimed in  claim 19 , wherein the internal diameter of the plurality of second steam generation tubes is not less than a minimum diameter determined on the basis of prescribed operating parameters. 
     
     
         21 . The continuous evaporator as claimed in  claim 19 , wherein the internal diameter of the plurality of second steam generation tubes includes a value between 20 and 40 mm. 
     
     
         22 . The continuous evaporator as claimed in  claim 17 , wherein the plurality of second steam generation tubes are connected one after another on the heating gas side as rows of tubes. 
     
     
         23 . A waste heat steam generator, comprising:
 a continuous evaporator as claimed in  claim 17 .   
     
     
         24 . The waste heat steam generator as claimed in  claim 23 , wherein upstream from the waste heat steam generator on the heating gas side is connected a gas turbine. 
     
     
         25 . The waste heat steam generator as claimed in  claim 23 , wherein an internal diameter of the plurality of second steam generation tubes is chosen such that the mean mass flow density which is established in the plurality of second steam generation tubes when operating at full load does not fall below the prescribed minimum mass flow density. 
     
     
         26 . The waste heat steam generator as claimed in  claim 25 , wherein the internal diameter of the plurality of second steam generation tubes is not less than a minimum diameter determined on the basis of prescribed operating parameters. 
     
     
         27 . The waste heat steam generator as claimed in  claim 25 , wherein the internal diameter of the plurality of second steam generation tubes includes a value between 20 and 40 mm. 
     
     
         28 . The waste heat steam generator as claimed in  claim 23 , wherein the plurality of second steam generation tubes are connected one after another on the heating gas side as rows of tubes.