Hydro­gen plays a key role in the green trans­ition

Vedyllä on merkittävä rooli vihreässä siirtymässä

To combat climate change, we need new ways of pro­du­cing energy. Hydro­gen has attrac­ted perhaps the most wide­spread interest as a poten­tial replace­ment for fossil fuels. Oilon’s exper­i­ence in hydro­gen com­bus­tion spans more than three decades.

Hydro­gen may be the most abund­ant element in the uni­verse, but on Earth, it doesn’t exist on its own freely. There are many ways to produce hydro­gen. It can be derived from fossil fuels or pro­duced through elec­tro­lysis: by split­ting water molecules with elec­tri­city. Addi­tion­ally, hydro­gen is pro­duced as a by-​product of chem­ical pro­cesses. More than 95% of the hydro­gen cur­rently pro­duced is derived from fossil fuels, and the rest from water with elec­tri­city through elec­tro­lysis. Pro­du­cing hydro­gen through elec­tro­lysis has an effi­ciency of around 60–70%. If the con­ver­ted hydro­gen needs to be trans­formed back to elec­tri­city e.g. through com­bus­tion, the round-​trip effi­ciency of the process is only around 30%. Con­sequently, hydro­gen is not an effi­cient altern­at­ive for using elec­tri­city dir­ectly.

Due to its envir­on­ment­ally friendly nature, hydro­gen pro­duced with renew­able elec­tri­city is referred to as green hydro­gen. The amount of green hydro­gen we will need in the future is enorm­ous. To illus­trate, the amount of renew­able elec­tri­city required to produce enough green hydro­gen to cover the current pro­duc­tion of fossil hydro­gen alone sur­passes EU’s annual elec­tri­city con­sump­tion. This would mean 4,000 TWh or around 160,000 new major 6 MW wind farms. A good start­ing point, to be sure.

In the fight against climate change, we need to use all the tools at our dis­posal. Every­where around the world, there are major ini­ti­at­ives on large-​scale green hydro­gen pro­duc­tion. The European Com­mis­sion estim­ates that in the next three decades, European gov­ern­ments will invest a total of EUR 470 billion into renew­able hydro­gen.

In the green trans­ition, hydro­gen is seen to have great poten­tial as a form of energy storage that would even out pro­duc­tion spikes in renew­able energy pro­duc­tion. In prac­tical terms, this would mean pro­du­cing hydro­gen with surplus elec­tri­city gen­er­ated by decent­ral­ized solar plants and wind farms. This hydro­gen would act as storage for the energy pro­duced.

Hydro­gen com­bus­tion – special con­sid­er­a­tions and applic­a­tions

“Oilon has more than 30 years of exper­i­ence in firing fuels that contain hydro­gen. We offer several hydrogen-​compatible burner models,” says Oilon’s Chief Tech­no­logy Officer Joonas Kat­telus.

Oilon’s entire range of burners for gaseous fuels is well suited for firing mix­tures with up to 20% hydro­gen content without modi­fic­a­tion. If hydro­gen content is increased to 20–70 per cent, a nozzle struc­ture spe­cific­ally designed for the purpose must be used. At higher levels (70–100%) and when there is vari­ation in the fuel’s hydro­gen content, a com­pre­hens­ive solu­tion designed for hydro­gen com­bus­tion is usually required.

Com­pared to natural gas, 100% hydro­gen has a lower density and energy content per unit of volume. Pure hydro­gen is extremely flam­mable, and it burns very intensely with a hot flame. Hydro­gen needs to be fed into the flame zone in a way that pre­vents damage to the burner’s nozzles and struc­tures. It is also import­ant that the fuel stream and its flow rate is appro­pri­ately aligned and con­trolled. There are some other lim­it­a­tions, such as that premix burner solu­tions are unsuit­able for firing 100% hydro­gen. As hydro­gen is extremely flam­mable, safety is an abso­lute pri­or­ity. All gas pipes must be equipped for purging the lines with non-​combustible gas. The most common solu­tion is to use nitro­gen to flush hydro­gen out of the pipes when the burner is switched off.

Hydro­gen as a fuel

“Oilon has designed and delivered hun­dreds of burners for dif­fer­ent hydro­gen mix­tures across the globe. Hydro­gen content varies from a few per cent all the way to 100 per cent. Over the years, we have accu­mu­lated extens­ive expert­ise in the field. Thanks to this, we are well equipped to utilize hydro­gen in burner com­bus­tion,” Kat­telus says.

A typical use case for hydro­gen com­bus­tion is the metal industry with its extremely high pro­duc­tion tem­per­at­ures. Another sector that uses hydro­gen as an energy source is the chem­ical industry, where hydro­gen is pro­duced as a byproduct. For oil refiner­ies, Oilon has delivered several pro­jects where the fuel used is refinery gas. The chem­ical com­pos­i­tion of refinery gases tends to vary greatly, which means there are large fluc­tu­ations in hydro­gen content.

In steel pro­duc­tion, coke oven gas (COG) gen­er­ated as part of the process and blast furnace gas (BFG) are com­monly used as a source of energy. COG has a high hydro­gen content, while BFG’s hydro­gen content is lower. Some of the COG and BFG pro­jects Oilon has com­pleted have involved extremely strict emis­sion require­ments. Addi­tion­ally, Oilon has extens­ive exper­i­ence in town gas com­bus­tion. Depend­ing on the pro­duc­tion process, the hydro­gen content of the fuel can vary greatly, the highest levels being 70 per cent.