— Before starting a discussion of the features of the hydrogen sensor, which is being developed at the Moscow Aviation Institute, I would like to talk with you about the importance of hydrogen as an energy carrier in the modern world, especially in the context of the course towards carbon neutrality, according to which technologies are developing in Russia and practically in the rest of the world?
- Humanity is aimed at the transition to environmentally friendly types of energy.
In this context, hydrogen as an energy carrier has a promising future.
It will certainly displace coal, fuel oil, diesel fuel, gasoline and natural gas.
Recently, H2 consumption has been growing and will continue to increase in the coming decades.
An important incentive is precisely the policy of achieving carbon neutrality, that is, the rejection of carbon dioxide emissions into the atmosphere.
More specifically, we can foresee the emergence of a large number of thermal power plants operating on hydrogen.
The efficiency of such a station will reach 60%.
Approximately the same good indicator is given by the current gas-fired thermal power plants operating on methane, but hydrogen has a number of advantages.
First of all, it has the highest thermal conductivity among gaseous substances and, which is extremely important, allows you to easily regulate the operation of gas turbines, respectively, quickly change the output power.
At nuclear power plants, for example, it is absolutely impossible to do this in a short time.
Hydroelectric power stations are more flexible in terms of capacity change, but they can be built far from everywhere.
Hydrogen thermal power plants are very convenient to use during periods when the volume of consumption changes dramatically.
Perhaps most important for hydrogen power plants and the energy potential of H2 as a whole is for Europe, which is trying to use renewable energy sources (RES) as widely as possible, but has difficulty in ensuring energy balance in cloudy weather and when there is no wind.
In the context of the upcoming hydrogen revolution, our country also has certain ambitions.
Suffice it to say that almost all newly built pipelines, including Nord Stream 2, are made using materials and technologies that allow H2 to be pumped.
Russia could hypothetically become a major global producer and exporter of hydrogen.
True, for safety reasons, it is still better to mix "transit" hydrogen with other substances, for example, with methane.
At the outlet of the pipe in the territory of the consumer country, this mixture will be separated into two gases.
And for export, it is easiest to use the underwater pipeline, because for pumping through the land artery, you will inevitably have to create a fairly extensive infrastructure for pumping and servicing.
Broad prospects are opening up for hydrogen in the automotive technology segment.
This trend has also affected our country.
It is known that in the near future in Moscow it is planned to create an extensive fleet of hydrogen electric buses.
gas power plant
© gazprom.ru
- However, as far as I understand, ambitious plans for a larger use of hydrogen as an energy carrier are constrained by the safety factor?
- Not only.
A number of issues regarding the choice of the most optimal methods for producing hydrogen have not been resolved.
There is a so-called green hydrogen, which is extracted from water by electrolysis.
In this case, no CO2 emissions are generated, but this method is energy intensive and quite costly.
There is blue hydrogen - it is extracted from methane, but with it CO2 is formed.
About security.
On the one hand, in any case, this issue must be taken very seriously, on the other hand, the risks of mass use of hydrogen should not be exaggerated.
For example, an industry that has long used hydrogen as an element for chemical reactions has, in essence, solved safety issues.
There are certain security gaps in new sectors of industry that are specifically aimed at using H2 as an energy carrier.
In everyday life, and in general, as I think, hydrogen will not be used soon.
Of course, when talking about the attractiveness and future expansion of hydrogen applications, it is impossible to ignore its shortcomings, which most directly affect safety.
The first is storage complexity.
H2 has the ability to penetrate even through hard surfaces.
Its spread is restrained only by a shell of metals, and even then not all of them.
The second is flammability, the limit of which is much wider than that of hydrocarbons and methane.
For an explosion to occur, the concentration of H2 in the environment must be between 4 and 75%.
For comparison: for methane, this range is much narrower - from 4 to 15%.
- Actually, for this reason, it is important to conduct accurate and timely measurements of the concentration of H2. What are the problems of modern hydrogen level sensors? Why did MAI decide to create a new product?
— Currently, in Russia and abroad, sensors are widely used that are focused on determining the concentration of various combustible gases and vapors.
They have both advantages and disadvantages.
The approach of the AHP team is to use a selective sensor that measures only H2 and does not sense other gases.
Creating a sensor that detects (determines) only hydrogen from a variety of mixtures of other substances is a very difficult task.
But, from our point of view, such a product is necessary and in demand, since it will be much better to take into account the most important properties of hydrogen: its fluidity, explosiveness, combustion temperature.
What does such a sensor look like?
“Our sensor is a compact product that will fit in a case with a volume of less than one cubic centimeter.
The actual size of the product is smaller, and the "sensitive" part of the sensor is quite small - it is a spiral about 0.5 mm long and about 0.3 mm in diameter.
Prototype gas analyzer with prototype MAI sensor
© photo provided by the MAI press service
Separately, such a sensor is not used, it is one of the components of the equipment of ready-made measuring devices, in our case it is a gas analyzer.
In order to easily integrate our sensor into the gas analyzer, a standard housing with a diameter of 8 mm and a height of 10 mm was chosen.
In fact, we could make the sensor even more compact, but there is no point in “shrinking” it yet, since it needs to be built into standard gas analyzers.
- And who exactly is working on this sensor?
– A group of graduate students, employees and graduates of the Department of Radioelectronics, Telecommunications and Nanotechnologies of Institute No. 12 Aerospace Science-Intensive Technologies and Production of the Moscow Aviation Institute is working on the project.
I am its leader.
Last year, our project became the winner of the competition for grants from the Russian Science Foundation in the direction of "Conducting fundamental scientific research and exploratory scientific research by small individual scientific groups."
- What else are the features of the sensor that the group under your leadership is working on?
— Our sensor belongs to the type of thermal catalytic sensors.
In addition to this class of sensors, there are electrochemical, semiconductor and optical.
Due to a number of features, they cannot detect hydrogen with high efficiency.
For example, electrochemical and semiconductor sensors sin by capturing hydrogen concentrations that are “harmless” from the point of view of explosiveness and, conversely, often “choke”, that is, lose sensitivity when the H2 level approaches a truly threatening threshold.
In this respect, thermal catalytic products compare favorably with other types of sensors.
They are the most suitable for measuring hydrogen in air in the range from 0.1 to 2% and higher, which most effectively helps to prevent explosive situations.
The essence of the operation of a thermal catalytic sensor is that hydrogen penetrates through the sensor membrane, behind which a sensitive element is placed, which is heated by current.
This element in turn has a surface coated with a catalyst.
It is necessary to heat the gas in order to cause a chemical reaction and thus detect hydrogen.
Heating is precisely the principle of operation of a thermal catalytic sensor.
Without a catalyst, a temperature of about 900 °C is required, and with a platinum catalyst, which is now widely used, about 300–400 °C.
The problem with modern thermal catalytic sensors is that at such high temperatures it is difficult to completely eliminate the possibility of situations when, during a short circuit and other malfunctions, a reaction will occur that can provoke an explosion.
It will be much safer if the heating temperature can be significantly lowered.
Today, the most advanced sensors give results at 200°C.
Our goal is to further reduce the hydrogen measurement temperature.
The strategic goal of the MAI project is to conduct selective measurements of hydrogen in air or in mixtures with other combustible gases at temperatures close to room temperature.
In addition to improving safety, it will be possible to reduce energy consumption.
As a result, the battery life of the sensor will increase.
There is no point in lowering the operating temperature completely to room temperature.
A good result, from our point of view, will be a product that functions when heated to 60-70 °C.
Last year we developed a catalyst that operates at just over 100°C, but now we are close to making a better sensor.
Hydrogen power plant
© gazprom.ru
The catalysts in current gas sensors are platinum group metals, but not all of them have previously been used to monitor hydrogen.
The novelty of our work lies in the use of iridium (Ir) and rhodium (Rh) in its pure form, form or mixed with platinum (Pt) and palladium (Pd).
This combination of materials should improve the parameters and performance of our thermal catalytic sensor.
This is a fairly low operating temperature, low power consumption, selectivity, sensitivity, reduced response time (reaction to hydrogen), long-term stability of operation.
The body of the product will be made in an explosion-proof design.
If, nevertheless, there is a sharp increase in the concentration of hydrogen, a short circuit or another incident, then it will prevent detonation.
- When do you plan to complete the project and what plans does the MAI team have for the production of the sensor?
— This year the work will continue and will be completed in 2023.
The results that we will obtain during the implementation of the project are of great importance in the context of the development and optimization of the parameters of thermal catalytic hydrogen sensors.
They will also expand the range of their practical application to new promising areas.
If we talk directly about the plans for the sensor, then, of course, we are sure that it will find its application in finished products.
Currently, we are closely cooperating with the Scientific and Technical Center for Measuring Gas-Sensing Sensors named after V.I.
E.F.
Karpov, which is engaged in the production and supply of sensors that detect combustible gases - primarily methane and propane-butane.
Thus, our calculation is that this enterprise will expand its field of activity by offering customers end products that can effectively detect hydrogen.
Naturally, we expect interest in the new sensor from other equipment manufacturers.
The market for gas sensors does not stand still, it is constantly developing and growing.