It also means the conversion of electric energy via hydrogen to hydrogen-based synthetic fuels and feedstock. The aim of this new technology is to help decarbonise the world.
Carbon-free energy
The process to produce hydrogen requires huge amounts of energy and the traditional hydrogen production methods using fossil fuels emit a lot of CO2. Today, 95% of all hydrogen is produced by steam methane reforming (SMR), a process in which natural gas is reacted with steam to produce hydrogen and carbon monoxide. The carbon monoxide is converted to carbon dioxide by subsequent reaction, again with steam.
Industry decarbonisation, the move from hydrocarbon-fueled economies to CO2-free or CO2-neutral hydrogen-fueled production, will not be easy and fast. To advance plans to cut down CO2 emissions, many countries are investing in new, more sustainable methods utilising blue – and especially green – hydrogen.
Green hydrogen – carbon-free energy
The production of blue and green hydrogen doesn’t release carbon dioxide to the atmosphere. CO2 does occur in the production of blue H2, but the production of green hydrogen is completely free of carbon emissions. Blue hydrogen is produced through the traditional process (SMR) and the carbon dioxide removed is either used in other processes or stored for the long-term. Green hydrogen production uses renewable energy, such as wind, hydro, or solar power.
Green hydrogen is produced by water (H2O) electrolysis. Hydrogen and oxygen are separated by connecting metallic electrodes to direct electric current (DC) and dipped into water. The surrounding water gets split, while the hydrogen appears at the cathode and the oxygen at the anode.
The benefits of green hydrogen compared to traditional methods
1. Carbon-free energy storage and transport: Green hydrogen is a great carrier of sources of energy including wind, hydro and solar power.
2. Production of green hydrocarbons and chemicals: Carbon dioxide-free production of, e.g., fertiliser, eMethane and eMethanol.
Burning green hydrocarbons emits greenhouse gases, but those are taken from the atmosphere during production, so the carbon emission balance is neutralised.
Using hydrogen to power our mobility keeps the air clean. The biggest positive effect will be in high-density population clusters, such as big cities. To sum it up, the new methods are an important element in meeting the targets of the Paris climate agreement.
Safe hydrogen production: The role of valves in Power-to-X
What role do valves play in all of this? The feedstocks, products and by-products of Power-to-X technologies are mainly gaseous, but also liquids and steam need to be handled. Heat transfer fluids may also need to be efficiently handled. Valves are needed to control the processes and to make them safe.
The production and utilisation of hydrogen requires accurate and reliable flow control. Based on extensive experience in the flow control of critical media like O2 and H2, Neles claims that its valves can make production operations not only safer, but also more efficient. Neles offers the services of experts to help size the right valve unit also for challenging process requirements.
Says Steve Clarke, MD of Neles South Africa, “Neles has a proven safety track record with tens of thousands of hydrogen and oxygen applications in industrial gas applications, in the chemical industry and in refineries. In addition, our high-capacity valve trim solutions contribute to increased efficiency.
“What are the best Neles valve solutions for Power-to-X technologies? There are several types of valves applied in this process, but our triple eccentric butterfly valve L-series and the segment valve R-series are two good examples."
Valves for hydrogen transport
Continues Clarke, “There are various methods to transport hydrogen. Whether transporting hydrogen by using ammonia or liquid organic compounds as a carrier, Neles offers a wide range of valves for both. For example, its valves have been operating in many ammonia plants all around the world for decades. For the chemical industry, where the flow control of organic compounds is common, Neles provides suitable valve solutions for the new LOHC technology to transport hydrogen over long distances. The new Power-to-X technologies can also benefit from our proven track record of reliability and efficiency. For the transporting of pure hydrogen, either liquefied or compressed, our high-performance Neles triple-eccentric butterfly valves are capable of meeting the cryogenic H2 boiling point of -253°C. Neles offers valve solutions for safe shutoff and control up to pressure class ASME CL2500.”
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