Heat damper for a waste heat recovery unit and waste heat recovery unit comprising a heat damper

Abstract

The disclosure concerns a waste heat recovery unit comprising a main heat exchanger configured to exchange heat between an exhaust fluid from a heat source and a working fluid of a waste heat recovery system, wherein the waste heat recovery unit comprises an additional heat exchanger configured to exchange heat between the exhaust fluid and alternatively a cooling fluid or a portion or the whole of said working fluid during transitory states.

1 . A waste heat recovery unit comprising a main heat exchanger configured to exchange heat between a hot exhaust fluid stream from a heat source and a working fluid stream of a waste heat recovery system, wherein the waste heat recovery unit comprises an additional heat exchanger arranged upstream said main heat exchanger, the additional heat exchanger being configured to exchange heat between the hot exhaust fluid stream and a cooling fluid stream. 
     
     
         2 . The waste heat recovery unit according to  claim 1 , wherein a diverter is arranged downstream said additional heat exchanger, the diverter being configured to control the amount of the hot exhaust fluid stream directed to said main heat exchanger and to a bypass duct. 
     
     
         3 . The waste heat recovery unit according to  claim 1 , wherein a diverter is arranged upstream said additional heat exchanger, the diverter being configured to control the amount of the hot exhaust fluid stream directed to said main heat exchanger and to a bypass duct. 
     
     
         4 . The waste heat recovery unit according to  claim 1 , wherein said additional heat exchanger is made with a high grade material. 
     
     
         5 . The waste heat recovery unit according to  claim 1 , wherein said additional heat exchanger is configured as a removable portion of the waste heat recovery unit. 
     
     
         6 . The waste heat recovery unit according to  claim 1 , wherein the waste heat recovery unit comprises a working fluid feed line, a bypass stream line connected at a first end to the working fluid feed line and at a second end to the additional heat exchanger and a main stream line connected at a first end to the working fluid feed line and at a second end to a first end of a main heat exchanger feed line; the waste heat recovery unit additionally comprising a preheated working fluid line connected at one end to a working fluid exit of the additional heat exchanger and at a second end to the first end of the main heat exchanger feed line, the second end of the main heat exchanger feed line being connected to the main heat exchanger. 
     
     
         7 . The waste heat recovery unit according to  claim 6 , wherein a separator is arranged downstream the preheated working fluid line and upstream the main heat exchanger feed line. 
     
     
         8 . The waste heat recovery unit according to  claim 7 , wherein a vapor stream line is connected at a first end with an upper portion of the separator and at a second end with the first end of the main heat exchanger feed line and wherein a liquid stream line is connected with a lower portion of the separator. 
     
     
         9 . The waste heat recovery unit according to  claim 6 , wherein the main stream line comprises a valve connected to a temperature sensor arranged along the main heat exchanger feed line. 
     
     
         10 . The waste heat recovery unit according to  claim 1 , wherein the waste heat recovery unit comprises a cooling fluid feed line connected at a first end to a service cooling fluid circuit and at a second end to the inlet of the additional heat exchanger and a cooling fluid outlet line connected at a first end to the outlet of the additional heat exchanger and at a second end to the service cooling fluid circuit, and wherein the waste heat recovery unit comprises a working fluid feed line connected to the main heat exchanger. 
     
     
         11 . The waste heat recovery unit according to  claim 10 , wherein a heat exchanger is configured to exchange heat between the cooling fluid downstream the additional heat exchanger and the working fluid upstream the main heat exchanger. 
     
     
         12 . The waste heat recovery unit according to  claim 1 , wherein said waste heat recovery unit is a once through heat recovery steam generator.