LAUSR

The first quarter of the year is a busy time for the process safety community in the U.S. with many preparing for the AIChE Spring Meeting and Global Congress on Process Safety (GCPS). The theme of the Spring Meeting was “Embracing the Future of Chemical Engineering.” The keynote, lunch speakers, and many other presentations mentioned energy transition, alternative energy, and/or sustainability. It seemed fitting to choose hydrogen as a focus area for this issue of Process Safety Progress. Hydrogen will play a big role in many upcoming energy transition projects. The use of hydrogen is increasing rapidly. Understanding of hydrogen hazards needs to evolve just as rapidly to prevent hydrogen incidents. In our process of reviewing papers for GCPS, we discovered what was for us a new term, “Colors of Hydrogen.” Essentially, as extracted from, the color depends upon the type of production used. Briefly, gray hydrogen comes from natural gas and related products. Blue hydrogen is from fossil fuels. Green hydrogen is from electrolysis using “clean electricity from surplus renewable sources.” Brown hydrogen is produced from coal or lignite. Purple hydrogen is produced by electrolysis using nuclear energy. Yellow hydrogen is produced directly from solar energy. Three other colors used are turquoise (for hydrogen produced by methane pyrolysis), pink (for hydrogen produced by electrolysis using nuclear energy), and white (for hydrogen, that is, naturally occurring hydrogen that may exist in underground deposits). We remember a phrase Dennis Hendershot used many times when accident investigations went into the details. Paraphrasing, “It doesn't really matter what type of hydrogen it is.” Hydrogen is a serious hazard that will present challenges to the process safety community as this technology is integrated into commercial uses. With an increased flammability range and lower ignition energy, hydrogen poses increased hazards over natural gas. Many of the upcoming hydrogen projects will use existing natural gas infrastructure with blended hydrogen fuels. Blended fuels will be used in equipment and buildings not originally designed for these fuels. We are pleased to present four articles that discuss the current state of process safety knowledge involving hydrogen. Our first article, by Marszal et al., discusses the detection of hydrogen in process areas. Our second article, by MacNguyen et al., compares hydrogen and hydrocarbon fuel hazards and includes risk management strategies. Our third article, by Ott et al., discusses piping material and specification issues with blended hydrogen/natural gas fuels and includes a discussion of impurity effects. Our fourth article, by Malik et al., covers recent very lean hydrogen vapor cloud explosion testing. We hope these articles increase your knowledge of hydrogen challenges and risks.