Method for detecting abnormality in process for exchanging heat

Abstract

The present invention provides a method for detecting abnormality in a process for exchanging heat between a heating medium and a process fluid comprising the step of: detecting a gaseous component at a gas phase in a flow path of the heating medium, wherein the gaseous component is generated by contact of the heating medium with the process fluid. This method can promptly detect a leakage of the process fluid in a process for exchanging heat between a heating medium and a process fluid.

What is claimed is:  
     
         1 . A method for detecting abnormality in a process for exchanging heat between a heating medium and a process fluid comprising the step of: 
 detecting a gaseous component at a gas phase in a flow path of the heating medium, wherein the gaseous component is generated by contact of the heating medium with the process fluid.    
     
     
         2 . The method for detecting abnormality in a process for exchanging heat according to  claim 1 , wherein the heating medium is a fused salt containing sodium nitrite, the process fluid contains at least one compound selected from the group consisting of chlorine, hydrogen chloride, hydrogen sulfide and methyl mercaptan, and the gaseous component generated is nitrogen oxide or a combustible gas.  
     
     
         3 . The method for detecting abnormality in a process for exchanging heat according to  claim 2 , wherein the fused salt contains about 20 to about 90 wt % of sodium nitrite and has a melting point of about 100 to about 200° C.  
     
     
         4 . The method for detecting abnormality in a process for exchanging heat according to  claim 1 , wherein the gaseous component generated is nitrogen oxide and is detected by a controlled potential electrolysis type NOx detector.  
     
     
         5 . A device for detecting abnormality in a process for exchanging heat between a heating medium and a process fluid comprising: 
 a heat exchanger;    a heating medium tank;    a pump and pipes for circulating the heating medium between the heat exchanger and the heating medium tank;    a gas detector provided at a gas phase in a flow path of the heating medium for detecting a gaseous component generated by contact of the heating medium with the process fluid leaked into the flow path of the heating medium.    
     
     
         6 . The device for detecting abnormality in a process for exchanging heat according to  claim 5 , wherein the heating medium is a fused salt containing sodium nitrite, the process fluid contains at least one compound selected from the group consisting of chlorine, hydrogen chloride, hydrogen sulfide and methyl mercaptan, and the gaseous component generated is nitrogen oxide or combustible gas.  
     
     
         7 . The device for detecting abnormality in a process for exchanging heat according to  claim 6 , wherein the fused salt contains about 20 to about 90 wt % sodium nitrite and has a melting point of about 100 to about 200° C.  
     
     
         8 . The device for detecting abnormality in a process for exchanging heat according to  claim 5 , wherein the gaseous component generated is nitrogen oxide and is detected by a controlled potential electrolysis type NOx detector.