H
ydrogen is one of the most talked about – and fastest growing – clean sources of fuel, and it is leading the way in the energy transition. However, while hydrogen is growing at an incredible pace as a fuel, it is not a new resource. Hydrogen production originally started more than a century ago, and has been supported for decades by Baker Hughes’ valves in the refining industry, primarily as a reactant feed to treat unrefined oil and gas products. Many of today’s wells are pulling heavy crude oil, which contains a high percentage of sulfur. However, the end customer markets are demanding improved diesel fuel with lower sulfur content. By virtue of this conflict of supply and demand, new refinery improvements have soared over recent decades, with expansions and new greenfield projects adding hydrotreating and hydrocracking units that inject hydrogen into the process to support this low sulfur content conversion. In addition, many refineries now include catalytic reforming – a chemical process used to create high octane products that generate hydrogen as a byproduct. As global demand for hydrogen increases, these proven and cost-effective methods of hydrogen production should remain a constant for many years to come.
Decades of process improvement The oldest, but still most common hydrogen production method, is steam reforming of natural gas. This moderate pressure production technology has been around for generations and has led to many developments and improvements in hydrogen processing, including enhanced specifications such as the National Association of Corrosion Engineers (NACE), to address hydrogen embrittlement. As hydrogen has an incredibly low molecular weight, its tiny
February 2022 54 HYDROCARBON ENGINEERING
molecules can severely attack materials by easily penetrating voids, impacting castings, polymer diaphragms and other porous material surfaces if the materials are not properly specified. Further, as temperature increases, these molecules will diffuse into the steel at an even faster rate, combining with the carbon within the steel to form methane, leading to accelerated wear from corrosion. NACE hardness and radiographic quality specifications have emerged over the years to address embrittlement and corrosion from hydrogen. Within the steam methane reformer (SMR) there are several harsh applications that require severe service valve solutions. One example is when the process condensate lines with carbon dioxide (CO2), which creates a highly-corrosive carbonic acid requiring exotic trim materials depending on the level of concentration. Other applications such as the feed gas compressor anti-surge and recycle valves, and the carbon monoxide (CO) shift converter start-up vent valves, are examples of high-pressure reduction applications where rapid gas expansion will lead to high velocity and vibration-induced damage if not properly designed with multi-stage low noise trim. The pressure swing adsorption (PSA) plants add enhanced hydrogen purification, bringing the level to 99.99% purity – ideal for transportation and other energy uses. The greatest challenge within the PSA units is reliability due to continuous cycling, where valves are expected to exceed more than 100 000 cycles. Thorough laboratory validation is essential to ensure that the product is fit for the life cycle within these units.
