Green Hydrogen Production

As Europe ambitiously pursues its goals for greenhouse gas (GHG) emission reduction and economic decarbonization, the significance of green hydrogen in this endeavor cannot be overstated. Hydrogen, the simplest and most abundant element in the universe, stands at the forefront of this transformative journey. While the hydrogen industry has witnessed rapid growth recently, its application is not novel. The United Kingdom, a global leader in the hydrogen market, boasts over a century of hydrogen production and distribution. Currently, the global production of hydrogen exceeds 70 million tonnes annually, predominantly derived from fossil fuels. However, the evolution towards green hydrogen production is pivotal for achieving Europe’s environmental and economic objectives.

Electrolysis Process Overview

Green hydrogen production involves the separation of water into hydrogen and oxygen using electrolyzers. High-purity water is introduced into the electrolyzer to ensure the quality of the resulting hydrogen gas. There are two main types of electrolyzers:

• Alkaline Electrolyzers: Utilize a liquid alkaline electrolyte, typically potassium hydroxide.
• Proton Exchange Membrane (PEM) Electrolyzers: Use a solid polymer membrane as the electrolyte.

Electrolysis cells consist of an anode and a cathode separated by the electrolyte. Specialized materials like nickel or platinum are used for the electrodes to withstand the harsh conditions of electrolysis. The electrochemical reactions at the electrodes produce hydrogen gas at the cathode and oxygen gas at the anode.

Green hydrogen production plants are powered by renewable energy sources such as solar, wind, and hydroelectric power. This makes the process sustainable and environmentally friendly.

By strategically placing oxygen and hydrogen analyzers at several critical sample points, the operation of electrolyzers can be closely monitored and controlled, ensuring safe and efficient hydrogen production. However, traditional process analysis methods involving sample extraction, pressure reduction and venting to the atmosphere can compromise safety and environmental integrity in high-pressure hydrogen systems, posing additional risks.

Optimal Locations for Measuring Oxygen and Hydrogen in Electrolyzers

• Oxygen and hydrogen content are typically measured at several critical sample points to ensure safety, process efficiency and product purity. These points include:
• Anode Outlet: Since oxygen is produced at the anode, measuring the oxygen content at the anode outlet is crucial for monitoring the electrolysis process and ensuring that the oxygen is safely collected and managed.
• Cathode Outlet: Hydrogen is produced at the cathode, so measuring the hydrogen content at the cathode outlet is essential for assessing the purity and quantity of hydrogen being generated.
• Electrolyzer Cell Outlet: At the point where the gases exit the electrolyzer, both oxygen and hydrogen concentrations are measured to detect any crossover or leaks within the cell. This helps ensure that the gases are properly separated and that the electrolyzer is operating efficiently.
• Gas Purification System Inlet and Outlet: Before and after the gas purification system, it is important to measure the hydrogen and oxygen content to verify the effectiveness of the purification process and ensure the final product meets the required purity standards.
• Storage and Distribution Points: Before hydrogen is stored or distributed, its purity is measured to confirm that it meets the specifications for its intended use, whether for fuel cells, industrial processes, or other applications.
• Safety Monitoring Points: Throughout the hydrogen production facility, especially in areas where gases are stored or handled, continuous monitoring of hydrogen and oxygen levels is essential for detecting leaks and preventing the formation of explosive mixtures

In-situ Oxygen and Hydrogen Analyzers in Electrolyzers

The emergence of optical technologies, such as laser spectroscopy, tunable diode lasers and quenched fluorescence, has revolutionized in-situ process analysis. These advanced techniques enable real-time measurements directly within the process stream, eliminating the need for sample extraction. Optical methods are inherently more resilient to harsh conditions, as they rely on light-based interactions rather than physical contact with the medium being measured. This not only improves measurement accuracy but also reduces the risk of contamination or wear on the sensors, making them ideal for environments such as petrochemical plants, refineries and natural gas processing facilities.

The MOD-1040 Oxygen Analyzer utilizes advanced optical sensor technology, making it ideal for in-situ monitoring. The MOD-1060 Hydrogen Analyzers is based on the principle of thermal conductivity, which is ideal for measuring gases with significantly different thermal conductivities, such as H2 and O2.

One of the key factors driving the increased adoption of in-situ analyzers is the development of more reliable electronics capable of withstanding harsh industrial conditions. Modern in-situ analyzers, such as the MOD-1040 Process Oxygen and MOD-1060 Process Hydrogen Analyzers are equipped with ATEX/IECEx certifications for explosion-proof environments and are designed to function seamlessly in areas with extreme temperature fluctuations, pressure variations, and hazardous gases. These systems are now equipped with highly reliable CPUs and electronics that provide robust data processing capabilities, even in challenging conditions.

In industries where safety is paramount, such as hydrogen production, natural gas processing and petrochemical refining, in-situ analyzers play a critical role in monitoring vital parameters like oxygen content, hydrogen concentration, and other critical gas compositions. The ability to perform real-time, continuous analysis ensures that operators can respond swiftly to changes in process conditions, reducing the risk of accidents or inefficiencies. For example, in flare stacks or burner systems, continuous monitoring of oxygen levels is crucial for optimizing combustion efficiency and preventing dangerous emissions. The MOD-1040 Process Analyzer, provides an advanced solution for such applications, offering low detection limits and rapid response times that were previously unattainable.

Similarly, the MOD-1060 Hydrogen Analyzer has proven to be a game-changer in the field of hydrogen production, blending and process control. Using thermal conductivity technology, it can measure hydrogen concentrations in real time, ensuring the safety and efficiency of hydrogen-natural gas blends. These advancements are particularly important as industries shift towards decarbonization and the use of green hydrogen in energy systems.

Benefits of In-Situ Analysis

 Wide Measurement Range: Capable of measurement across a broad spectrum.
 Fast Response Time: Essential for real-time monitoring.
 High Accuracy and Precision: Ensures reliable measurements for safety and quality.
 Low Maintenance: Requires less frequent calibration and replacements.
 Versatility: Suitable for gases monitoring across various industries.
 Reduced Interference: Accurate readings with minimal cross-interference from other gases.
 Enhanced Safety: Reduces the risk of explosions and fires by ATEX / IECEX / SIL2 approvals.
 Operational Efficiency: Improves process control and product purity.
 Cost Savings: Simplifies system design and reduces the need for equipment hazardous area classification.

Technical Specifications

In conclusion, the evolution of in-situ technologies for on-line process analysis has bridged the gap between traditional, labor-intensive methods and modern, efficient, real-time solutions. As these technologies continue to evolve, in-situ analyzers will play an increasingly pivotal role in ensuring operational efficiency, safety, and environmental compliance in industrial processes worldwide.

We invite all stakeholders and interested parties to subscribe to our Modcon Industry Insights for the latest updates, innovations, and insights in hydrogen technology. For more information on the MOD-1040 Oxygen and MOD-1060 Process Hydrogen Analyzers or to subscribe to our newsletter, please visit our website or contact us for more information.

Please also visit our webpage Green Hydrogen Production to learn more about In-situ Oxygen and Hydrogen Analyzers in Electrolyzers.