What are the important technologies for hydrogen energy?
The hydrogen energy industry chain has four major links, namely hydrogen production, hydrogen storage, hydrogen refueling stations, and fuel cells.
Do you know which link is the key point at this stage and requires the most technical input? Listen, I'll tell you the answer.
In fact, in 2018-2020, most of the key projects in the hydrogen energy industry are concentrated on hydrogen fuel cells, accounting for 51.9%.
However, since 2021, the country has increased the research and development of hydrogen production and hydrogen storage technology, and the proportion of its research and development projects has increased significantly.
Hydrogen production, hydrogen storage and fuel cells began to be on an equal footing, with the three major links accounting for 32%.
This is because the application of hydrogen fuel cells is inseparable from hydrogen production and hydrogen storage. Fuel cells are applications, and hydrogen production and storage are the foundation. Only when the foundation is solid can applications develop better.
So speaking of this, what are the important technologies for hydrogen production?
In fact, the key technology involved in hydrogen production must be mentioned - pressure swing adsorption technology (PSA) of mixed gas
The basic principle is: the adsorption of gases by adsorbents is selective, that is, the adsorption capacity of different gases on the adsorbent is different, and the adsorption capacity of a specific gas on the adsorbent will vary with the pressure. The changing characteristics enable separation of gas mixtures and regeneration of adsorbents.
To put it simply, the gas containing hydrogen is put into the PSA unit, impurities other than hydrogen are removed, and high-purity hydrogen is extracted.
I believe some people will ask, but this is hydrogen extraction, not hydrogen production, which is different from what I said before?
Yes, PSA can only purify hydrogen, not hydrogen, but the reason why it focuses on it is that most of the current hydrogen production methods cannot produce high-purity hydrogen, and finally PSA is required for the final step of purification. it goes without saying.
So isn't there a way to make high-purity hydrogen in one go?
In fact, there is, that is, electrolysis of hydrogen, and this is another important technology for hydrogen production that we are discussing today.
The so-called electrolysis of water to produce hydrogen means that under the action of direct current, water molecules are dissociated into hydrogen and oxygen through an electrochemical process, which are separated out at the cathode and anode respectively, and then hydrogen with a purity of up to 99.99% can be directly obtained.
Moreover, the electrolysis of water hydrogen production technology is also regarded as the key core technology of green renewable energy hydrogen production, because whether it is fossil energy hydrogen production or industrial by-product hydrogen production, these mainstream hydrogen production technologies will produce carbon emissions in the production process. , poor environmental protection.
The use of renewable energy electrolytic hydrogen can play its true role as a green and clean energy.
According to this statement, electrolytic hydrogen technology should be used all over the world, right?
But the opposite is true. Today, more than 95% of the world's hydrogen is produced from fossil fuels, and only about 4% is obtained through the electrolysis of water.
So why is electrolytic hydrogen, which is obviously more environmentally friendly and green, difficult to become the mainstream?
In fact, the reason is very simple, that is, high cost and immature technology.
At present, there are three mainstream production methods for hydrogen production technology from water electrolysis, namely alkaline water electrolysis cell, proton exchange membrane water electrolysis cell and solid oxide water electrolysis cell. The first method is too expensive, and the second and third methods are The technology is just getting started and immature.
But this situation is not difficult to change. Hydrogen production from renewable energy is the future development direction of hydrogen energy.