Vapour Compression Distillation: Energy efficient system for rinse water recovery/re-use
In this project Ship Company, a printed circuit board (PCB) fabricating company, investigated the application of two separate technologies – vapour compression distillation for energy efficient distillation and a rotating cylinder cathode electrochemical cell for metal recovery.
Ship Company had already made an investment in a closed loop etching process prior to this project. Etching is where copper metal is etched from the copper mother board to form the desired circuit pattern.
The aim of this project was to look at the rinse streams subsequent to this closed loop etching process to try and recover and reuse rinse water and a more concentrated stream which could feed back to the etching process.
Ship Company decided to investigate vapour compression distillation (VCD) in conjunction with other recycling strategies to achieve the aim of the project of zero rinse water emission and zero waste transport.
However it was found that with ammonia present, vapour compression distillation was not an option that could work.
As part of this project it was determined that significant quantities of ammonia with entrapped copper salts were being emitted in the closed loop etching process. The company designed an in-house recovery system which has reduced ammonia use. This had an added benefit of recovering and reusing entrained droplets of etch solution from air emissions from the process.
For further details, download the Ship Company PDF.
