Chloro- and bromo-fluoro olefin compounds useful as organic rankine cycle working fluids

Abstract

Aspects of the present invention are directed to working fluids and their use in processes wherein the working fluids comprise compounds having the structure of formula (I): wherein R 1 , R 2 , R 3 , and R 4 are each independently selected from the group consisting of: H, F, Cl, Br, and C 1 -C 6 alkyl, at least C 6 aryl, at least C 3 cycloalkyl, and C 6 -C 15 alkylaryl optionally substituted with at least one F, Cl, or Br, wherein formula (I) contains at least one F and at least one Cl or Br, provided that if any R is Br, then the compound does not have hydrogen. The working fluids are useful in Rankine cycle systems for efficiently converting waste heat generated from industrial processes, such as electric power generation from fuel cells, into mechanical energy or further to electric power. The working fluids of the invention are also useful in equipment employing other thermal energy conversion processes and cycles.

We claim: 
     
         1 . A process for converting thermal energy to mechanical energy in a Rankine cycle comprising:
 vaporizing a working fluid with a hot heat source;   expanding the resulting vapor and then cooling with a cold heat source to condense the vapor; and   pumping the condensed working fluid;   
       wherein the working fluid comprises at least one compound having the formula (I): 
       
         
           
           
               
               
           
         
       
       wherein R 1 , R 2 , R 3 , and R 4  are each independently selected from the group consisting of: H, F, Cl, Br, and C 1 -C 6  alkyl, at least C 6  aryl, at least C 3  cycloalkyl, and C 6 -C 15  alkylaryl optionally substituted with at least one F, Cl, or Br, wherein formula (I) contains at least one F and at least one Cl or Br, provided that if formula (I) contains Br, then it also contains no hydrogen. 
     
     
         2 . The process of  claim 1  wherein at least one of R 1 , R 2 , R 3 , and R 4  is methyl, ethyl, or propyl, optionally substituted with at least one F, Cl, or Br. 
     
     
         3 . The process of  claim 1  wherein the compound comprises the formula CxFyHzCl n  wherein y+z+n=2× or CxFyBr n  wherein y+n=2× and x is at least 3, y is at least 1, z is 0 or a positive number, and n is 1 or 2. 
     
     
         4 . The process of  claim 1  wherein the compound is selected from the group consisting of C 3 F 3 H 2 Cl, CF 3 CF═CFCF 2 CF 2 Cl, CF 3 CCl═CFCF 2 CF 3 , and mixtures thereof. 
     
     
         5 . The process of  claim 1  wherein the working fluid is selected from the group consisting of 1-chloro-3,3,3-trifluoropropene (Z), 1-chloro-3,3,3-trifluoropropene (E), and combinations thereof. 
     
     
         6 . The process of  claim 1  wherein the working fluid is 2-bromo-1,1,3,3,3-pentafluoropropene. 
     
     
         7 . A process for converting thermal energy to mechanical energy comprising:
 heating a the working fluid to a temperature sufficient to vaporize the working fluid and form a pressurized vapor of the working fluid; and   causing the pressurized vapor of the working fluid to perform mechanical work;   
       wherein the working fluid comprises at least one compound having the formula (I): 
       
         
           
           
               
               
           
         
       
       wherein R 1 , R 2 , R 3 , and R 4  are each independently selected from the group consisting of: H, F, Cl, Br, and C 1 -C 6  alkyl, at least C 6  aryl, at least C 3  cycloalkyl, and C 6 -C 15  alkylaryl optionally substituted with at least one F, Cl, or Br, wherein formula (I) contains at least one F and at least one Cl or Br, provided that if formula (I) contains Br, then it also contains no hydrogen. 
     
     
         8 . The process of  claim 7  further comprising transmitting the mechanical work to an electrical device. 
     
     
         9 . The process of  claim 8  wherein the electrical device is a generator to produce electrical power. 
     
     
         10 . A process for a binary power cycle comprising a primary power cycle and a secondary power cycle, wherein a primary working fluid comprising high temperature water vapor or an organic working fluid vapor is used in the primary power cycle, and a secondary working fluid is used in the secondary power cycle to convert thermal energy to mechanical energy wherein the secondary power cycle comprises:
 heating the secondary working fluid to form a pressurized vapor and   causing the pressurized vapor of the secondary working fluid to perform mechanical work,   
       wherein the secondary working fluid comprises at least one compound having the formula (I): 
       
         
           
           
               
               
           
         
       
       wherein R 1 , R 2 , R 3 , and R 4  are each independently selected from the group consisting of: H, F, Cl, Br, and C 1 -C 6  alkyl, at least C 6  aryl, at least C 3  cycloalkyl, and C 6 -C 15  alkylaryl optionally substituted with at least one F, Cl, or Br, wherein formula (I) contains at least one F and at least one Cl or Br, provided that if formula (I) contains Br, then it also contains no hydrogen. 
     
     
         11 . A process for converting thermal energy to mechanical energy comprising a Rankine cycle system and a secondary loop; wherein the secondary loop comprises a thermally stable sensible heat transfer fluid interposed between a heat source and the Rankine cycle system and in fluid communication with the Rankine cycle system and the heat source to transfer heat from the heat source to the Rankine cycle system without subjecting a working fluid of the organic Rankine cycle system to heat source temperatures;
 wherein the Rankine cycle system working fluid comprises at least one compound having the formula (I):   
       
         
           
           
               
               
           
         
         wherein R 1 , R 2 , R 3 , and R 4  are each independently selected from the group consisting of: H, F, Cl, Br, and C 1 -C 6  alkyl, at least C 6  aryl, at least C 3  cycloalkyl, and C 6 -C 15  alkylaryl optionally substituted with at least one F, Cl, or Br, wherein formula (I) contains at least one F and at least one Cl or Br, provided that if formula (I) contains Br, then it also contains no hydrogen. 
       
     
     
         12 . An organic Rankine cycle working fluid comprising at least one compound having the formula (I): 
       
         
           
           
               
               
           
         
       
       wherein R 1 , R 2 , R 3 , and R 4  are each independently selected from the group consisting of: H, F, Cl, Br, and C 1 -C 6  alkyl, at least C 6  aryl, at least C 3  cycloalkyl, and C 6 -C 15  alkylaryl optionally substituted with at least one F, Cl, or Br, wherein formula (I) contains at least one F and at least one Cl or Br, provided that if formula (I) contains Br, then it also contains no hydrogen. 
     
     
         13 . The working fluid of  claim 12  wherein at least one of R 1 , R 2 , R 3 , and R 4  is methyl, ethyl, or propyl, optionally substituted with at least one F, Cl, or Br. 
     
     
         14 . The working fluid of  claim 12  wherein the compound comprises the formula CxFyHzCl n  wherein y+z+n=2× or CxFyBr n  wherein y+n=2× and x is at least 3, y is at least 1, z is 0 or a positive number, and n is 1 or 2. 
     
     
         15 . The working fluid of  claim 12  wherein the compound is selected from the group consisting of C 3 F 3 H 2 Cl, CF 3 CF═CFCF 2 CF 2 Cl, CF 3 CCl═CFCF 2 CF 3 , and mixtures thereof. 
     
     
         16 . The working fluid of  claim 12  wherein the compound is selected from the group consisting of 1-chloro-3,3,3-trifluoropropene (Z), 1-chloro-3,3,3-trifluoropropene (E), and combinations thereof. 
     
     
         17 . The working fluid of  claim 16  wherein said working fluid consists essentially of 1-chloro-3,3,3-trifluoropropene (Z), 1-chloro-3,3,3-trifluoropropene (E), and combinations thereof. 
     
     
         18 . The working fluid of  claim 16  wherein said working fluid consists essentially of 1-chloro-3,3,3-trifluoropropene (Z). 
     
     
         19 . The working fluid of  claim 12  wherein the compound is 2-bromo-1,1,3,3,3-pentafluoropropene. 
     
     
         20 . The working fluid of  claim 19  wherein the working fluid consists essentially of 2-bromo-1,1,3,3,3-pentafluoropropene.