Electric vehicles powered by hydrogen fuel cells are becoming more popular. This is not surprising — using hydrogen as a source of electricity for the power plant allows us to solve the main problems of electric vehicles — long charging times and short mileage. At the same time, a hydrogen vehicle also does not produce emissions and operates almost silently, but it can be refueled in just a few minutes, and the driving range without refueling becomes the same as that of traditional gasoline cars.
According to the International Energy Agency, about 8 thousand hydrogen fuel cell vehicles were sold worldwide in 2021 alone. The UN Economic Commission for Europe estimates the number of hydrogen cars at 15 thousand and believes that their number will only grow. Experts suggest that by 2050, a quarter of the world’s transport will use hydrogen as an energy source.
So far, the only operating hydrogen filling station, equipped for autonomy with an industrial PEM hydrogen generator produced by Polycom. This experimental facility is designed to test various types of hydrogen transport.
PRINCIPLE OF BUILDING A HYDROGEN FILLING STATION (HFS)
A typical chain of operation of an air defense plant usually includes:
- Source of hydrogen (usually an electrolyser, a plant for producing hydrogen from methane, a source of imported hydrogen)
- Intermediate low pressure hydrogen storage tank
- Gas station module
- Intermediate high pressure hydrogen storage tank
- Refueled vehicle
Sometimes some nodes of this chain are made combined with others
FILLING STATION MODULE
The filling station module provides hydrogen compression up to 400 bar, as well as hydrogen switching for filling a high-pressure hydrogen storage tank and subsequent rapid refueling of vehicles
Typical composition of a hydrogen filling station:
- Insulated container with all systems
- Diaphragm compressor 400 atm
- Ports for connecting a high pressure storage tank
- Electrical cabinets and security systems
- Gas subsystem
- Refueling nozzle and metering unit
- Control system for coordination with the hydrogen generator module
PRINCIPLE OF OPERATION OF A HYDROGEN FILLING STATION BASED ON A HYDROGEN GENERATOR (ELECTROLYSER) FOR REFUELING VEHICLES WITH AN OPERATING PRESSURE OF 350 ATM
The hydrogen generator produces hydrogen, which is stored under pressure up to 40 atm in a low-pressure accumulator. As it fills, a hydrogen compressor is turned on, which pumps hydrogen into a high-pressure storage tank, where it is stored at 400 atm.
Refueling of a vehicle is carried out using a filling hose and a pistol by transferring hydrogen from a high-pressure accumulator into the vehicle tank. In this case, the rate of hydrogen flow, its temperature and pressure are controlled. The metering unit records the specified parameters and also calculates the amount of hydrogen supplied.
To avoid overheating the vehicle tank, it is common to supercool the hydrogen «on the fly» during the refueling process. For these purposes, a hydrogen cooler based on a low-temperature chiller is used.
More modern refueling protocols use an infrared interface to communicate between the vehicle and the refueling nozzle. Using this interface, the vehicle reports to the vehicle in real time the status of its own tank, in particular hydrogen pressure, temperature and fill level.
EXAMPLE OF BUILDING A SMALL HYDROGEN FILLING STATION
Vehicle tank capacity – 200 Nm 3 /h
The target pressure in the vehicle tank is 350 atm.
Refueling frequency – 1 time per day
The hydrogen generator used is Polycom A-10
Hydrogen generator | Gas station module | Vehicle |
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Low pressure tank | Compressor | High pressure accumulator |
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Produces hydrogen at | Physical volume Hydrogen storage at pressures in the range of | Delivers a pressure of 400 bar Productivity – 12 Nm3/h | Physical volume Hydrogen storage at pressures in the range of | Gets of 200 Nm3 hydrogen for 1 filling |
ALGORITHM OF OPERATION
Step 1. The storage tanks are charged at 40 and 400 bar.
Step 2. Refueling the vehicle (200 Nm 3 ). The pressure in the high-pressure storage tanks drops to 350 bar.
Step 3. The compressor turns on and pumps hydrogen from the low-pressure tank to the high-pressure tank within 15-16 hours. The hydrogen generator operates at 10 Nm 3 /h, replenishing the low pressure tank.
Step 4. The pressure in the tanks has become 10 and 400 bar, but the fuel filling station is already ready to refuel the vehicle.
Step 5. Over the next 3 hours, the hydrogen generator fills the low pressure tank from 10 to 40 bar and turns off.
Thus, such a filling station allows to refuel a vehicle at 200 Nm 3 with a cycle of just under 1 day.
It should be understood that this example is given only to illustrate the principle of constructing hydrogen filling stations. In the operation of real hydrogen filling station, there is a significant number of additional nuances and know-how aimed at optimizing the operation of units and increasing the reliability of operation.