(Oil & Gas 360) – While much of the hydrogen discussion centers around green and blue hydrogen and their differences in processing (e.g., eliminating emissions versus carbon capture), results, and energy-derived, evolving hydrogen technologies yield new applications and colors.
Among the types being produced today is black hydrogen derived from coal gasification. Despite its negligible impact on carbon emissions, some companies and countries with abundant coal reserves are still exploring this method. Monolith, a company in Nebraska, utilizes methane pyrolysis to create carbon black and hydrogen while virtually eliminating emissions.
Brown hydrogen is produced using lignite (brown coal) through a similar gasification process. Like black hydrogen, it is associated with high carbon emissions and is less favored in the push towards cleaner energy. With its vast coal reserves, lax environmental standards, and a quest to advance its energy technologies, China is the world leader in black and brown hydrogen.
China also leads the world in producing grey hydrogen, another hydrogen extraction technique from fossil fuels.
Grey hydrogen can be used to clean fuels by removing sulfur. It is also used to produce ammonia for fertilizers and methanol and treat certain metals like steel. It is even used to hydrogenate fats and oils in the food industry.
Orange hydrogen is an emerging process for extracting hydrogen from plastic waste via pyrolysis (high heat, oxygen-free), microwave catalysts, and photo reforming (light-driven chemical reactions). It is being pursued because it offers the dual advantages of energy production and waste management amid what many see as an intractable plastic waste problem.
Pink hydrogen is derived from water electrolysis powered by nuclear power. It is not renewable but does not generate CO2 emissions. It is showing commercial promise.
Purple hydrogen combines nuclear power and heat to more efficiently split water through chemo-thermal electrolysis.
Red hydrogen uses nuclear heat and water (steam) through thermolysis to reduce the amount of electricity required to separate the hydrogen.
Monolith in Nebraska is also considered to be on the technological edge of using turquoise hydrogen via what it calls its plasma-arc approach, a variation of methane pyrolysis in which high temperatures facilitate the degradation of natural gas into hydrogen. Solid carbon is another by-product. Solid carbon has numerous commercial uses and does not contribute to emissions.
Yellow hydrogen is simply green hydrogen powered by solar energy.
White hydrogen is naturally occurring hydrogen from the earth, formed by water interacting with iron-rich minerals under high pressures and temperatures. Companies like Koloma and Hydroma are pursuing commercial viability.
Despite being the most abundant element in our solar system, hydrogen on Earth must be extracted from molecules that contain it in compounds.
By Jim Felton for oil&gas360.com
