Injection of premixed concentrated chemical solution in steam generator chemical cleaning

Abstract

A steam generator chemical cleaning system is provided wherein a concentrated chemical cleaning solution is premixed off-site in sufficient volume and concentration to allow the dilution to proper cleaning level be achieved by slow injection into the generator when filled with demineralized water. The premixed chemicals are transported in a tanker to the generator site and injected therein directly from the tanker.

1 . A method of chemically cleaning a steam generator comprising the steps of:
 premixing a concentrated solution of chemicals for a steam generator off-site from the generator;   delivering the premixed solution to the site of the generator;   partially filling the generator with demineralized water;   recirculating the water in the generator through equipment for bringing the water to proper chemical cleaning conditions;   injecting the premixed solution into the recirculated water until the solution is diluted to proper generator cleaning concentrations and levels; and   cleaning the generator with the diluted premixed chemical solution.   
   
   
       2 . A method as set forth in  claim 1  including the step of drawing the chemical solution from the generator to a waste tanker for off-site disposal. 
   
   
       3 . A method as set forth in  claim 1  including the step of stopping the injection of premixed solution after it reaches generator cleaning levels and maintaining the recirculation thereof. 
   
   
       4 . A method as set forth in  claim 1  including the step of sensing the chemical concentration in the generator during the step of injecting the premixed solution into the recirculated water. 
   
   
       5 . A method as set forth in  claim 1  including the step of loading a volume of premixed concentrated chemical solution into a tanker volume to dilute the demineralized water in a water filled generator to proper cleaning levels when fully injected into the generator. 
   
   
       6 . A method as set forth in  claim 1  including the step of flushing the generator with clean demineralized water after the completion of the chemical cleaning process. 
   
   
       7 . A method as set forth in  claim 6  wherein the flushing water is recirculated through an ion exchanger column to completely clean the generator.