Oxygen enhanced combustion in industrial processes

Abstract

The present invention relates to a system for carrying out oxygen-enhanced combustion in an industrial process wherein the industrial process, an oxygen supply system or a source of oxygen, a heat recovery network, and an alternative Rankine cycle system based on a working fluid other than steam are integrated to achieve improved throughput and efficiency, and a method for oxygen-enhanced combustion in an industrial process using said system. Examples of industrial processes include cement production, steel reheat applications, glass production, aluminum and copper melting, as well as any industrial process that uses process heater, furnaces where combustion is carried out using an oxidant stream with oxygen content higher’ than that in ambient air and up to 100%.

1 . A system for carrying out oxygen-enhanced combustion in an industrial process comprising the industrial process system, an oxygen supply source, a heat recovery unit, and an alternative Rankine cycle system based on a working fluid other than steam, wherein
 a) the oxygen supply system supplies oxygen to the industrial process,   b) the industrial process generates waste heat as at least one heat source which is sent to the heat recovery unit,   c) the waste heat is then sent from the heat recovery unit to the alternative Rankine cycle system,   d) the alternative Rankine cycle system converts the waste heat to power, which is utilized by the oxygen supply system or the industrial process or is exported to a utility system.   
   
   
       2 . The system of  claim 1  wherein the industrial process system comprises a process heater or furnaces where combustion is carried out using an oxidant stream with oxygen content in the range from higher than that in ambient air to up to 100%. 
   
   
       3 . The system of  claim 2 , wherein the industrial process is selected from the group consisting of cement production, steel reheat applications, glass production, aluminum melting and copper melting. 
   
   
       4 . The system of  claim 1 , wherein the oxygen supply source is an air separation unit. 
   
   
       5 . The system of  claim 4 , wherein the air separation unit is a cryogenic unit, a pressure swing adsorption system, a vacuum pressure swing adsorption system or a membrane system. 
   
   
       6 . The system of  claim 1 , wherein the oxygen supply source is a liquid delivery system or a pipeline supply system. 
   
   
       7 . The system of  claim 1 , wherein the heat recovery unit comprises heat exchangers that enable heat transfer between the heat source and the working fluid of the alternative Rankine cycle system and may employ an intermediate heat transfer fluid. 
   
   
       8 . The system of  claim 7 , wherein the intermediate heat transfer fluid is thermal oil or air. 
   
   
       9 . The system of  claim 1 , wherein the alternative Rankine cycle system has at least two heat sources which are generated from the industrial process. 
   
   
       10 . The system of  claim 1 , wherein flue gas from the heat recovery unit is partially recirculated to the industrial process system. 
   
   
       11 . The system of  claim 1 , wherein the working fluid of the alternative Rankine cycle system is an organic substance. 
   
   
       12 . The system of  claim 11 , wherein the working fluid of the alternative Rankine cycle system is a refrigerant, a hydrocarbon, an aromatic, or an aromatic perfluorocarbon. 
   
   
       13 . The system of  claim 12 , wherein the working fluid of the alternative Rankine cycle system is siloxane or a siloxane mixture. 
   
   
       14 . The system of  claim 1 , wherein the system for carrying out oxygen-enhanced combustion further comprises an additional firing heater. 
   
   
       15 . The system of  claim 1 , wherein the industrial process is a cement manufacturing process. 
   
   
       16 . The system of  claim 1 , wherein the industrial process is a steel reheat process. 
   
   
       17 . A system for carrying out oxygen enhanced combustion in an industrial process comprising the industrial process system and an oxygen supply source, wherein there is 100% oxygen enhanced combustion and partial recirculation of flue gases. 
   
   
       18 . A method for carrying out oxygen-enhanced combustion in an industrial process using the system of  claim 1 . 
   
   
       19 . A method for carrying out oxygen-enhanced combustion in an industrial process using the system of  claim 17 .