Potential Problems Blending Hydrogen with Natural Gas

Natural gas systems are abundant and blending hydrogen into the gas stream seems logical. There are natural gas pipelines all over the world with compressor stations and storage systems to keep the gas flowing. At the end of the natural gas pipelines are a variety of systems designed to convert the natural gas in a process into other beneficial products or to simply burn it as fuel. All these systems were designed and constructed specifically for natural gas. The first obvious concern is the metallurgy used in the construction of equipment was designed for primarily methane and may be susceptible to hydrogen embrittlement. Next, if the blended gas escapes containment, the gas detector technology and detector locations were designed specifically for the methane in natural gas and the blended product has different characteristics that will may make the detectors ineffective at detecting the gas leak. At best, this might result in delayed alarms and delayed mitigation. Blending hydrogen with natural gas will also affect the burner safe operating limit curves. Hydrogen has different chemical and physical properties that will change the risks profile of the equipment used to move, burn, and process natural gas. This paper and presentation will discuss the potential problems in detail and changes required to continue to provide manageable risk to people, assets, and the environment.