US-12623931-B2 - Pulsed power supply for sustainable redox agent supply for hydrogen abatement during electrochemical hypochlorite generation

US12623931B2US 12623931 B2US12623931 B2US 12623931B2US-12623931-B2

Abstract

A method of operating an electrochemical cell including introducing an aqueous solution into the electrochemical cell, applying a current across an anode and a cathode to produce a product, monitoring the voltage, dissolved hydrogen, or a condition of the aqueous solution, and applying the current in a pulsed waveform responsive to one of the measured parameters is disclosed. An electrochemical system including an electrochemical cell including an anode and a cathode, a source of an aqueous solution having an outlet fluidly connectable to the electrochemical cell, a sensor for measuring a parameter, and a controller configured to cause the anode and the cathode to apply the current in a pulsed waveform responsive to the parameter measurement is disclosed. Methods of suppressing accumulation of hydrogen gas within the electrochemical cell are also disclosed. Methods of facilitating operation of an electrochemical cell are also disclosed.

Inventors

George Y Gu
Michael J Shaw
Joshua Griffis
Simon P Dukes

Assignees

EVOQUA WATER TECHNOLOGIES LLC

Dates

Publication Date: 20260512
Application Date: 20231011

Claims (13)

1 . An electrochemical system comprising: an electrochemical cell including a housing having an inlet, an outlet, an anode, and a cathode disposed within the housing; a source of an aqueous solution having an outlet fluidly connectable to the inlet of the electrochemical cell; one or more sensors constructed and arranged to measure parameters of the aqueous solution selected from the group consisting of flow rate, dissolved oxygen concentration, dissolved hydrogen concentration, pH, ORP, and temperature of the aqueous solution; and a controller electrically connectable to the one or more sensors and configured to cause current to be applied across the anode and cathode in pulses of less than 500 seconds at a cathodic potential of less than 1.6 volts and to control the parameters of the aqueous solution to maintain the cathodic potential.
2 . The electrochemical system of claim 1 , wherein the controller is further configured to cause current to be applied across the anode and the cathode in a pulsed waveform responsive to one or more parameters of the aqueous solution being outside of a predetermined range.
3 . The electrochemical system of claim 1 , wherein the controller is further configured to regulate a rate of introduction of the aqueous solution into the electrochemical cell based on the one or more parameters of the aqueous solution.
4 . The electrochemical system of claim 1 , wherein the controller is configured to cause the current across the anode and the cathode to be applied in a pulsed waveform responsive to a dissolved hydrogen concentration in a product solution generated in the electrochemical cell being sufficient to cause accumulation of hydrogen at the cathode during operation of the electrochemical cell.
5 . The system of claim 1 , wherein the controller is further configured to regulate the anode and the cathode in one or more of a duration of pulses of the current, a rate of incidence of pulsed current, and a magnitude of the current applied across the anode and the cathode based on at least one of a flow rate of the aqueous solution, the cathodic potential, a concentration of oxygen dissolved in the aqueous solution, and a concentration of hydrogen dissolved in the aqueous solution.
6 . The electrochemical system of claim 1 , further comprising a source of an oxidizing agent fluidly connectable to the source of the aqueous solution upstream of the electrochemical cell.
7 . The electrochemical system of claim 6 , wherein the source of the oxidizing agent is constructed and arranged to deliver hydrogen peroxide to the source of the aqueous solution from the outlet of the electrochemical cell.
8 . The electrochemical system of claim 6 , wherein the controller is further configured to regulate a rate of introduction the oxidizing agent into the aqueous solution based at least on one of an amount of hydrogen gas present in the electrochemical cell, a concentration of hydrogen dissolved in the aqueous solution, a concentration of oxygen dissolved in the aqueous solution, and a concentration of oxygen dissolved in a product solution generated in the electrochemical cell.
9 . The electrochemical system of claim 1 , further comprising a second one or more sensors constructed and arranged to measure a condition of a product solution generated in the electrochemical cell selected from the group consisting of flow rate, pH, ORP, temperature, and concentration of a product compound in the product solution.
10 . The electrochemical system of claim 9 , wherein the controller is electrically connectable to the second one or more sensors and is further configured to regulate a rate of introduction of the aqueous solution into the electrochemical cell based on the condition of the product solution.
11 . The electrochlorination system of claim 1 , wherein the source of the aqueous solution comprises at least one of seawater, brackish water, and brine.
12 . The system of claim 1 , further comprising a second one or more sensors constructed and arranged to measure a concentration of dissolved hydrogen in a hypochlorite-containing product solution generated in the electrochemical cell, the controller being electrically connectable to the second one or more sensors and being further configured to cause current to be applied across the anode and the cathode in a pulsed waveform responsive to the dissolved hydrogen concentration exceeding a predetermined threshold.
13 . The system of claim 1 , further comprising a second one or more sensors constructed and arranged to measure electrical properties of a hypochlorite-containing product solution generated in the electrochemical cell, to generate a current-voltage plot from the measured electrical properties, and to cause current to be applied across the anode and the cathode in a pulsed waveform responsive to an inflection point in the current-voltage plot being indicative of a concentration of dissolved hydrogen in the hypochlorite-containing product solution exceeding a predetermined threshold.

Description

CROSS-REFERENCE TO RELATED APPLICATION This application claims priority under 35 U.S.C. § 119(e) to U.S. Provisional Application Ser. No. 62/468,544, filed on Mar. 8, 2017, titled “Implementation of Feedback Control for Improved Electrochemical System Design,” U.S. Provisional Application Ser. No. 62/467,518, filed on Mar. 6, 2017, titled “Half-Cell Electrochemical Configurations for Self-Cleaning Electrochlorination Devices,” and U.S. Provisional Application Ser. No. 62/469,224, filed on Mar. 9, 2017, titled “Pulsed Power Supply for Sustainable Redox Agent Supply for Hydrogen Abatement During Electrochemical Hypochlorite Generation,” each of which is herein incorporated by reference in its entirety for all purposes. FIELD OF TECHNOLOGY Aspects and embodiments disclosed herein are generally directed to electrochemical devices, and more specifically, to electrochlorination cells and devices, methods of operating same, and systems utilizing same. SUMMARY In accordance with an aspect, a method of operating an electrochemical cell is provided. The method may comprise introducing an aqueous solution into an electrochemical cell between an anode and a cathode of the electrochemical cell, applying a current across the anode and the cathode at a voltage sufficient to generate a product compound from the aqueous solution in the electrochemical cell, monitoring at least one parameter selected from the group consisting of the voltage, a concentration of dissolved hydrogen in a product solution generated in the electrochemical cell, and a condition of the aqueous solution associated with hydrogen gas production, and applying the current across the anode and the cathode in a pulsed waveform responsive to the at least one parameter being outside of a predetermined range. In some embodiments, the method may comprise selecting the condition of the aqueous solution from the group consisting of flow rate, dissolved oxygen concentration, dissolved hydrogen concentration, pH, ORP, and temperature of the aqueous solution being introduced into the electrochemical cell. The method may further comprise controlling one or more of a duration of pulses of the current, a rate of incidence of pulsed current, and a magnitude of the current applied across the anode and the cathode based on the condition of the aqueous solution. The method may further comprise controlling a rate of introduction of the aqueous solution based on the condition of the aqueous solution. In some embodiments, the method comprises selecting the predetermined range to be sufficient to prevent generation of hydrogen gas in the electrochemical cell. The method may comprise controlling one or more of a duration of pulses of the current, a rate of incidence of pulsed current, and a magnitude of the current applied across the anode and the cathode based on at least one of a flow rate of the aqueous solution, the voltage, and the concentration of dissolved hydrogen in the product solution. The method may comprise controlling a rate of introduction of the aqueous solution into the electrochemical cell based at least on one or more of a flow rate of the product solution out of the electrochemical cell, a concentration of the product compound in the product solution, and a concentration of chloride in the aqueous solution. In some embodiments, the method may comprise introducing an oxidizing agent into the aqueous solution upstream of the electrochemical cell. Introducing the oxidizing agent may comprise introducing one or more of gaseous oxygen, ozone, air, oxygen-enriched air, and hydrogen peroxide into the aqueous solution. The method may comprise applying current across the anode and the cathode in a pulsed waveform responsive to the voltage being outside a range of about 0.5 V and 4.0 V. In accordance with another aspect there is provided a method of suppressing accumulation of hydrogen gas in an electrochlorination cell. The method may comprise introducing a liquid electrolyte into an electrochlorination cell between an anode and a cathode of the electrochlorination cell, monitoring at least one parameter selected from the group consisting of a voltage applied across the anode and the cathode, a concentration of dissolved hydrogen in a product solution generated in the electrochlorination cell, and a condition of the liquid electrolyte selected from the group consisting of flow rate, dissolved oxygen concentration, dissolved hydrogen concentration, pH, ORP, and temperature of the liquid electrolyte being introduced into the electrochlorination cell, and applying the current across the anode and the cathode in a pulsed waveform responsive to the parameter being outside of a range sufficient to prevent generation of hydrogen gas within the electrochlorination cell. In accordance with another aspect, there is provided an electrochemical system comprising an electrochemical cell including a housing having an inlet, an outlet, an anode, and a cathode disposed within the h