Radiant Superheater

Abstract

A radiant superheater arranged to hang at the upper portion of a furnace of a boiler. The radiant superheater is substantially planar and includes a first vertical pass, a first connection pass, a second vertical pass, a third vertical pass, a second connection pass, and a fourth vertical pass. Each vertical pass includes an upper end and a lower end. The vertical passes are connected in series, so that steam to be superheated enters at the upper end of the first vertical pass and flows through the first vertical pass and from the lower end of the first vertical pass via the first connection pass to the lower end of the second vertical pass and through the second vertical pass and from the upper end of the second vertical pass to the upper end of the third vertical pass and through the third vertical pass and from the lower end of the third vertical pass via the second connection pass to the lower end of the fourth vertical pass and through the fourth vertical pass, to be discharged from the upper end of the fourth vertical pass. The first connection pass is arranged below the second connection pass so as to shield the second connection pass from radiation from the lower portion of the furnace.

1 . A radiant superheater arranged to hang at the upper portion of a furnace of a boiler, wherein the radiant superheater is substantially planar and comprises:
 a first vertical pass;   a first connection pass;   a second vertical pass;   a third vertical pass;   a second connection pass; and   a fourth vertical pass,   wherein each vertical pass comprises an upper end and a lower end, the vertical passes are connected in series, so that steam to be superheated enters at the upper end of the first vertical pass and flows through the first vertical pass and from the lower end of the first vertical pass via the first connection pass to the lower end of the second vertical pass and through the second vertical pass and from the upper end of the second vertical pass to the upper end of the third vertical pass and through the third vertical pass and from the lower end of the third vertical pass via the second connection pass to the lower end of the fourth vertical pass and through the fourth vertical pass, to be discharged from the upper end of the fourth vertical pass, and   wherein the first connection pass is arranged below the second connection pass so as to shield the second connection pass from radiation from the lower portion of the furnace.   
     
     
         2 . The radiant superheater according to  claim 1 , wherein the first vertical pass and the second vertical pass are arranged to surround the fourth vertical pass and the third vertical pass, so as to shield, in a horizontal direction, the fourth vertical pass and the third vertical pass from radiation. 
     
     
         3 . The radiant superheater according to  claim 1 , wherein each of the first vertical pass, the first connection pass, the second vertical pass, the third vertical pass, the second connection pass and the fourth vertical pass comprises multiple parallel steam tubes. 
     
     
         4 . The radiant superheater according to  claim 3 , wherein each of the multiple parallel steam tubes of the first vertical pass is in steam flow connection to one of the multiple parallel steam tubes of the first connection pass and each of the multiple parallel steam tubes of the first connection pass is in steam flow connection to one of the multiple parallel steam tubes of the second vertical pass. 
     
     
         5 . The radiant superheater according to  claim 4 , wherein each of the multiple parallel steam tubes of the third vertical pass is in steam flow connection to one of the multiple parallel steam tubes of the second connection pass and each of the multiple parallel steam tubes of the second connection pass is in steam flow connection to one of the multiple parallel steam tubes of the fourth vertical pass. 
     
     
         6 . The radiant superheater according to  claim 5 , wherein the second vertical pass and the third vertical pass are connected in series so that the steam flows from the upper end of the second vertical pass via a third connection pass to the upper end of the third vertical pass, and the third connection pass comprises multiple parallel steam tubes. 
     
     
         7 . The radiant superheater according to  claim 6 , wherein each of the multiple parallel steam tubes of the second vertical pass is in steam flow connection to one of the multiple parallel steam tubes of the third connection pass, and each of the multiple parallel steam tubes of the third connection pass is in steam flow connection to one of the multiple parallel steam tubes of the third vertical pass. 
     
     
         8 . The radiant superheater according to  claim 3 , wherein the furnace comprises a roof, each of the multiple parallel steam tubes of the second vertical pass is connected to a first header arranged above the roof, each of the multiple parallel steam tubes of the third vertical pass is connected to a second header arranged above the roof, and the first header is in steam flow connection with the second header by a connecting pipe arranged outside the roof. 
     
     
         9 . The radiant superheater according to  claim 8 , wherein the connecting pipe comprises a water attemperator. 
     
     
         10 . The radiant superheater according to  claim 1 , wherein the first vertical pass is arranged adjacent to the front end side of the boiler and the second vertical pass is arranged adjacent to the back end side of the boiler. 
     
     
         11 . The radiant superheater according to  claim 10 , wherein the fourth vertical pass is arranged adjacent to the first vertical pass and the third vertical pass is arranged adjacent to the second vertical pass. 
     
     
         12 . The radiant superheater according to  claim 1 , wherein the radiant superheater is an intermediate superheater arranged in steam flow direction upstream of a high pressure steam turbine. 
     
     
         13 . The radiant superheater according to  claim 1 , wherein the radiant superheater is a finishing superheater arranged in steam flow direction upstream of a high pressure steam turbine. 
     
     
         14 . The radiant superheater according to  claim 1 , wherein the radiant superheater is an intermediate superheater arranged in steam flow direction downstream of a high pressure steam turbine. 
     
     
         15 . The radiant superheater according to  claim 1 , wherein the radiant superheater is a finishing superheater arranged in steam flow direction downstream of a high pressure steam turbine. 
     
     
         16 . The radiant superheater according to  claim 1 , wherein the boiler is one of a supercritical boiler and an ultra supercritical boiler.