Direct evaporator apparatus and energy recovery system

Abstract

In one aspect of the present invention provides a direct evaporator apparatus for use in an organic Rankine cycle energy recovery system, comprising: (a) a housing comprising a heat source gas inlet, and a heat source gas outlet, said housing defining a heat source gas flow path from said inlet to said outlet; and (b) a heat exchange tube disposed entirely within said heat source flow path, said heat exchange tube being configured to accommodate an organic Rankine cycle working fluid, said heat exchange tube comprising a working fluid inlet and a working fluid outlet, said heat exchange tube defining three zones, a first zone adjacent to said heat source gas outlet, a second zone adjacent to said heat source gas inlet, and a third zone disposed between said first zone and said second zone, said working fluid inlet being in direct fluid communication with said first zone, and said working fluid outlet being in direct fluid communication with said third zone; wherein said first zone is not in direct fluid communication with said third zone. An organic Rankine cycle energy recovery system and a method of energy recovery are also provided.

1 . A direct evaporator apparatus for use in an organic Rankine cycle energy recovery system, comprising:
 (a) a housing comprising a heat source gas inlet, and a heat source gas outlet, said housing defining a heat source gas flow path from said inlet to said outlet; and   (b) a heat exchange tube disposed entirely within said heat source flow path, said heat exchange tube being configured to accommodate an organic Rankine cycle working fluid, said heat exchange tube comprising a working fluid inlet and a working fluid outlet, said heat exchange tube defining three zones, a first zone adjacent to said heat source gas outlet, a second zone adjacent to said heat source gas inlet, and a third zone disposed between said first zone and said second zone, said working fluid inlet being in direct fluid communication with said first zone, and said working fluid outlet being in direct fluid communication with said third zone;   wherein said first zone is not in direct fluid communication with said third zone.   
     
     
         2 . The direct evaporator apparatus according to  claim 1 , wherein said heat exchange tube comprises a plurality of bends in each of the first zone, second zone and third zone. 
     
     
         3 . The direct evaporator apparatus according to  claim 2 , wherein the heat exchange tube is configured in parallel rows in each of the first zone, second zone and third zone. 
     
     
         4 . The direct evaporator apparatus according to  claim 3 , wherein in each of the first zone, second zone and third zone of the heat exchange tube is configured in at least one row. 
     
     
         5 . An organic Rankine cycle energy recovery system comprising:
 (a) a direct evaporator apparatus comprising (i) a housing comprising a heat source gas inlet and a heat source gas outlet, said housing defining a heat source gas flow path from said inlet to said outlet; and (ii) a heat exchange tube disposed entirely within said heat source flow path, said heat exchange tube being configured to accommodate an organic Rankine cycle working fluid, said heat exchange tube comprising a working fluid inlet and a working fluid outlet, said heat exchange tube defining three zones, a first zone adjacent to said heat source gas outlet, a second zone adjacent to said heat source gas inlet, and a third zone disposed between said first zone and said second zone, said working fluid inlet being in direct fluid communication with said first zone, and said working fluid outlet being in direct fluid communication with said third zone;   (b) work extraction device;   (c) a condenser; and   (d) a pump;   wherein the direct evaporator apparatus, work extraction device, condenser and pump a configured to operate as a closed loop.   
     
     
         6 . The energy recovery system according to  claim 5 , wherein said heat exchange tube comprises a plurality of bends in each of the first zone, second zone and third zone. 
     
     
         7 . The energy recovery system according to  claim 5 , wherein the heat exchange tube is configured in parallel rows in each of the first zone, second zone and third zone. 
     
     
         8 . The energy recovery system according to  claim 5 , further comprising a recouperator. 
     
     
         9 . The energy recovery system according to  claim 5 , wherein the work extraction device comprises a turbine. 
     
     
         10 . The energy recovery system according to  claim 9 , further comprising a turbine by-pass duct. 
     
     
         11 . A method of energy recovery comprising:
 (a) introducing a heat source gas having a temperature into a direct evaporator apparatus containing a liquid working fluid;   (b) transferring heat from the heat source gas having a temperature T 1  to the working fluid to produce a superheated gaseous working fluid and a heat source gas having temperature T 2 ;   (c) expanding the superheated gaseous working fluid having a temperature T 3  through a work extraction device to produce mechanical energy and a gaseous working fluid having a temperature T 4 ;   (d) condensing the gaseous working fluid to provide a liquid state working fluid; and   (e) returning the liquid state working fluid to the direct evaporator apparatus;   wherein the direct evaporator apparatus comprises (i) a housing comprising a heat source gas inlet, and a heat source gas outlet, said housing defining a heat source gas flow path from said inlet to said outlet; and a heat exchange tube disposed entirely within said heat source flow path, said heat exchange tube being configured to accommodate the working fluid, said heat exchange tube comprising a working fluid inlet and a working fluid outlet, said heat exchange tube defining three zones, a first zone adjacent to said heat source gas outlet, a second zone adjacent to said heat source gas inlet, and a third zone disposed between said first zone and said second zone, said working fluid inlet being in direct fluid communication with said first zone, and said working fluid outlet being in direct fluid communication with said third zone; and wherein said first zone is not in direct fluid communication with said third zone.   
     
     
         12 . The method according to  claim 11 , wherein the heat source gas has a temperature T 1  in a range from about 400° C. to about 600° C. 
     
     
         13 . The method according to  claim 11 , wherein the heat source gas has a temperature T 2  in a range from about 100° C. to about 250° C. 
     
     
         14 . The method according to  claim 11 , wherein the working fluid is a hydrocarbon. 
     
     
         15 . The method according to  claim 11 , wherein the working fluid is a hydrocarbon is selected from the group consisting of methylcyclobutane, cyclopentane, isopentane, cyclohexane, and methycyclopentane. 
     
     
         16 . The method according to  claim 11 , wherein the superheated gaseous working fluid has a temperature T 3  in a range from below 300° C. 
     
     
         17 . The method according to  claim 11 , wherein the work extraction device is a turbine 
     
     
         18 . The method according to  claim 11 , wherein the working fluid in the first zone is at a temperature in a range from about 20° C. to about 150° C. 
     
     
         19 . The method according to  claim 11 , wherein the working fluid in the second zone is at a temperature in a range from about 50° C. to about 300° C. 
     
     
         20 . The method according to  claim 11 , wherein the working fluid in the third zone is at a temperature in a range from about 200° C. to about 300° C.