This property, in combination with its broad flammability range of 4 - 74% by volume concentration in air and 4 - 94% in oxygen at atmospheric pressures, and its explosion limits of 18.3 - 59% by volume, makes hydrogen very susceptible to leakage. Consequently, explosion safety is a crucial consideration in the design of hydrogen containing systems.
A high oxygen level in hydrogen piping can pose a significant risk of an explosion or fire. Moreover, in chemical reactions and processes, a high oxygen content can also result in side reactions which reduce the efficiency of the process and also cause unwanted reactions, resulting in product contamination, reducing its quality, or forcing additional purification procedures. Therefore, accurate and reliable measurement of the oxygen content in high-pressure hydrogen piping is essential for increased process efficiency, product quality, and safety.
To mitigate the hazards associated with hydrogen production, systems must be carefully designed. Dedicated equipment rated for both non-hazardous and hazardous locations is typically used in hydrogen gas production systems. However, in an attempt to lower installation costs, general-purpose equipment may be utilised. The risk of gas leaks must be minimised. However, sampling gas from high-pressure pipelines for chemical analysis increases the potential for leaks, and can pose a challenge when performing oxygen analysis.
Traditionally, measuring the oxygen content in high-pressure hydrogen piping involves extracting a sample and reduction of the pressure of the sample for analysis. However, this method has several drawbacks, including complexity and inaccuracies caused by sample conditioning and handling. As a result, many companies are turning to the in-situ installation of oxygen analysers inside high-pressure hydrogen piping, which offers real-time measurement, reduced complexity, and improved accuracy.
Installation of an oxygen analyser directly into high-pressure hydrogen piping allows operators to continuously monitor the oxygen content in real-time, without the need for sample extraction or a pressure reducing sampling system. This method is not only faster and more efficient, but also much safer. It eliminates the risk of exposure of hydrogen to atmospheric oxygen and subsequently reduces the need for hazardous area classification.
Written by A. Kigel and A. Shats, Modcon Systems, UK,
Read the article online at: https://www.globalhydrogenreview.com/special-reports/28122023/focusing-on-oxygen-in-hydrogen-analysis/
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