Electrolytic On-Site Generator

Abstract

Method and apparatus for a low maintenance, high reliability on-site electrolytic generator incorporating automatic cell monitoring for contaminant film buildup, as well as automatically removing or cleaning the contaminant film. This method and apparatus preferably does not require human intervention to clean. For high current density cells, cleaning is preferably performed by reversing the polarity of the electrodes and applying a lower current density to the electrodes, preferably by adjusting the salinity or brine concentration of the electrolyte while keeping the voltage constant. Electrolyte flow preferably comprises water and brine flows which are preferably separately monitored and automatically adjusted. For bipolar cells, flow between modules arranged in parallel is preferably approximately equally distributed between modules and between intermediate electrodes within each module.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application is a divisional application of U.S. patent application Ser. No. 13 / 198,276, entitled “Electrolytic On-Site Generator”, filed on Aug. 4, 2011, which application claims priority to and the benefit of filing of U.S. Provisional Patent Application Ser. No. 61 / 371,585, entitled “Low Maintenance Electrolytic On-Site Generator,” filed on Aug. 6, 2010 and U.S. Provisional Patent Application Ser. No. 61 / 371,490, entitled “Reverse Polarity Cleaning and Electronic Flow Control Systems for Low Intervention Electrolytic Chemical Generators,” filed on Aug. 6, 2010, and which application is also a continuation-in-part application of U.S. patent application Ser. No. 12 / 473,744, entitled “Reverse Polarity Cleaning and Electronic Flow Control Systems for Low Intervention Electrolytic Chemical Generators”, filed on May 28, 2009, which application claims priority to and the benefit of filing of U.S. Provisional Patent Application Ser. No. 61...

AI Technical Summary

Benefits of technology

The system ensures continuous operation with reduced maintenance needs, preventing contaminant buildup and extending the life of electrolytic cells by automatically cleaning the electrodes, thus maintaining efficiency and reliability without the need for regular acid supplies or operator intervention.

Problems solved by technology

However, it is well accepted that one of the major failure mechanisms of undivided electrolytic cells is the buildup of unwanted films on the surfaces of the electrodes.

Typically these unwanted films consist of manganese, calcium carbonate, or other unwanted substances.

If buildup of these films is not controlled or they are not removed on a fairly regular basis, the electrolytic cells will lose operating efficiency and will eventually catastrophically fail (due to localized high current density, electrical arcing or some other event).

However, these contaminants will enter the process over time from contaminants in the salt used to make the brine.

However, these salt cleaning processes, although mandatory for effective operation of divided cells, are considered too complicated for smaller on-site generation processes that utilize undivided cells.

Other than these methods and / or visual inspection of the internal workings of a cell, there currently is not an adequate method of monitoring the internal status of the buildup on an electrolytic cell.

However, most dimensionally stable anodes for chlorine production in membraneless electrolytic cells producing chlorine at 8 gram per liter (8,000 mg / L) concentration of free available chlorine (FAC) cannot tolerate high current densities (greater than approximately 1 amp per square inch) in reverse polarity mode.

Thus, although simply reversing the polarity works for low current density electrolytic cells, it will not work for electrolytic cells which normally operate at a high current density, since the anode will be damaged if high current density is applied during the reverse polarity cleaning operation.

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