Hydrogen is the fuel with the highest energy content per weight. Unfortunately, the density of hydrogen in atmospheric conditions is only at 90 grams per cubic meter. To achieve usable levels of energy density, efficient compression of hydrogen is essential. We have far more than 100 years of experience in hydrogen compression offers a broad portfolio of hydrogen compressors.
One proven compression concept is the NEA|HOFER diaphragm compressor MKZ. These hydrogen compressors efficiently compress small to medium quantities of hydrogen to high and, if required, even extremely high pressures of more than 5,000 bar (75,000PSI). The diaphragm principle ensures oil- and leakage free compression with excellent product purity. Diaphragm compressors operate best under continuous load. When running under an intermittent operation regime the lifetime of the diaphragm can be lower and servicing could be increased.
For such volatile operating scenarios NEA|HOFER hydraulic driven dry running piston compressors (TKH) can be a viable alternative. The TKH is also able to reach very high pressures of up to 4,200 bar (60,000 PSI) and it also offers oil-, leakage and technically abrasion free compression. The number of strokes per minute can be easily controlled via the hydraulic control unit, this ensures an efficient capacity control. For small volume flows and high pressures, as e.g. required for hydrogen refueling stations, the TKH is the compressor of choice.
If high quantities of oil-free hydrogen with less than 250 bar (3,600 PSI) pressure are needed, our many thousand-fold proven and tested dry running API 618 piston compressors are the answer. Far more than 10 Megawatts of drive power can efficiently be used to fulfill any hydrogen compression requirement. If traces of oil are allowed in the gas, discharge pressures in the range of more than 600 bar (9,000 PSI) are possible with lubricated compression.
For high volume flows and high pressures, the combination of piston stages with diaphragm heads on a “hybrid” compressor offers a veritable hydrogen compressor solution.
With the Paris Agreement of 2015 Europe has set ambitious goals to protect the global climate. By 2030 the greenhouse gas emissions shall be reduced by 40 % in comparison to 1990. By 2050 Europe shall be climate neutral. To achieve the necessary energy transition and to be able to couple the sectors heat, industry and mobility with the electricity producing sector, independent from weather conditions, alternative energy carriers and storage methods are necessary. Hydrogen (H2) has a huge potential as an energy storage medium. Renewable energy such as wind, solar or hydro power can be converted into hydrogen and then be stored and transported with the help of hydrogen compressors. In this way a sustainable usage of natural resources can be combined with prosperity and development.
Together with battery electric vehicles (BEV) fuel cell electric vehicles (FCEV) with hydrogen as a fuel are the big topic for the mobility of the future. Standards are already in place, and they currently demand discharge pressures up to 1,000 bar. Depending on the required volume flow our NEA|HOFER hydrogen compressors of the TKH or MKZ type are the ideal solution.
The focus for hydrogen fueled road transport lies on the freight transportation with light and heavy trucks and semis. Since large amounts of energy are required here and the corresponding batteries have a very high dead weight, they limit the possible payload and are therefore less suitable as a storage solution. There are already quite a few providers of hydrogen fuel cell electric trucks on the market.
For rail-bound transport in areas without overhead line power supply, hydrogen powered trains can substitute the usage of diesel-powered machines. In many countries in the world the first handful of hydrogen-electric with an operational range of more than 800 km (500 miles) and top speeds of 140kph (85 mph) are already operational.
Hydrogen also finds its way into climate neutral zero emission maritime transport. The first ferries and smaller freight ships sailing on hydrogen currently undergo intense testing. Also, synthetic fuels made from hydrogen and captured CO2 are an option for climate neutral maritime transport. These tailor-made fuels can also become the fuel for the aviation of the future.
It can support the efficient sector coupling in the power-to-x approach in these applications. Power-to-steel for example has the goal of “de-fossilizing” steel production. Electric power is used for smelting processes. CO2 neutral hydrogen can be used as a substitute for coke in the reduction process. In refineries we can find the first projects which use hydrogen generated by electrolysis e.g. for desulphurization of fuels.
There are also small-scale industrial applications ranging from fuel cell powered fork-lifts to hydrogen fuel cell emergency power units. The latter supply, same as the micro fuel cells for houses and other buildings, power and heat and their only exhaust is clean water.
For storage and transport of hydrogen exist a lot of different possibilities. For small amounts of hydrogen metal-hydride storage or liquid organic hydrogen carriers (LOHC) can be used. The principle is that hydrogen under medium pressures is bound to a carrier material and can be released when needed via an endothermal process. Another storage and transport method used is in the filling of pressure vessels such as cylinder banks or tube trailers. For the transportation of big quantities from 10,000 to 1,000,000 Nm3/h of hydrogen, pipelines of corresponding diameter and operating pressure are suited best. They also offer a significant storage capacity. To able to bridge a several weeklong dark doldrum salt caverns offer an excellent energy storage possibility. The first pilot projects in this sector are already running in different countries.
Liquid hydrogen (LH2) is produced by compressing, cooling, and expanding hydrogen. To be fully liquid, it must be cooled down to -253°C (-423°F). As this process requires more energy than the compression process per kilogram of hydrogen, it is primarily foreseen for ocean crossing long distance transport with tankers where the construction of pipelines would not be reasonable.
One thing is obvious, whenever hydrogen needs to be stored or transported, efficient compression with modern compressor plants is of paramount importance.
