A Hydrogen Compressor is a device that can compress hydrogen gas to a high pressure state, mainly used to increase the pressure of hydrogen gas to meet specific needs of hydrogen storage containers or usage processes. By inputting mechanical energy, the pressure of hydrogen is increased from low to high. Specifically, the working principles of different types of hydrogen compressors vary.
The following are the working principles of different types of hydrogen compressors:
Reciprocating hydrogen compressor: The motor drives the crankshaft to rotate, and the crankshaft drives the piston to reciprocate in the cylinder through the connecting rod. When the piston returns, negative pressure is formed inside the cylinder, the intake valve opens and the exhaust valve closes, and hydrogen gas is sucked into the cylinder to complete the suction process; When the piston pushes, it compresses hydrogen gas to increase its pressure. After reaching the exhaust pressure, the exhaust valve opens and the intake valve closes. The compressed hydrogen gas is discharged from the exhaust port to complete the exhaust. The continuous compression and delivery of hydrogen gas is achieved through the continuous reciprocating of the piston.
Centrifugal hydrogen compressor: When working, the prime mover is started to rotate the impeller, and the blades of the impeller drive the gas to rotate together, generating centrifugal force. Under the action of this centrifugal force, the gas is thrown along the blade channel towards the impeller outlet and sent into the discharge pipe through the volute shell. Gas obtains energy from the impeller, increasing pressure and kinetic energy, and relies on this energy to reach the work site. As the gas is continuously thrown towards the outlet of the impeller, a low-pressure zone is formed at the inlet of the impeller. The transported gas generates a pressure difference between the suction pipe and the impeller, and the gas in the suction pipe is continuously sucked into the chamber and the impeller under the action of this pressure difference, enabling the circulating hydrogen compressor to operate continuously.
Membrane separation hydrogen compressor: relying on specially designed membrane components, hydrogen is separated from the mixed gas and compressed. The hydraulic oil system consists of a crankshaft driven by an electric motor, reciprocating pistons, connecting rods, and oil circuit regulating valves. The reciprocating motion of the pistons generates hydraulic oil pressure, which drives the bottom membrane to move towards the gas side, compresses the gas, and discharges it.
Liquid driven hydrogen compressor: Using hydraulic oil as the driving medium, the hydraulic pump is driven by an electric motor to generate pressure. The hydraulic oil is controlled by an electromagnetic directional valve to move back and forth in the cylinder, pushing the piston to directly act on the hydrogen gas, thereby achieving the suction, compression, and discharge of hydrogen gas. When the piston returns, negative pressure is formed inside the cylinder, and hydrogen gas is sucked in; When the piston is pushed, hydrogen gas is compressed and discharged.
Diaphragm hydrogen compressor: driven by an electric motor, the crankshaft rotates, the crankshaft drives the connecting rod, and the connecting rod drives the piston to perform reciprocating motion. The piston uses hydraulic oil to drive the diaphragm. The diaphragm is clamped by the gas side diaphragm head and the oil side diaphragm head along the periphery, and moves back and forth in the cylinder to compress and transport hydrogen gas. During the inhalation process, the diaphragm moves towards the oil side, creating negative pressure inside the cylinder, and hydrogen gas enters through the inhalation valve; During the compression and exhaust process, the diaphragm moves towards the gas side, compressing hydrogen gas and discharging it through the exhaust valve.
Linear compressor: using a linear motor to directly drive the piston to make reciprocating motion, the reciprocating motion of the piston in the cylinder changes the gas volume, achieving the compression of hydrogen gas. The rotor of a linear motor is directly connected to the piston, and the magnetic field force generated by alternating current drives the rotor to drive the piston to perform linear reciprocating motion, completing the process of hydrogen gas intake, compression, and exhaust.
Ionic liquid compressor: It uses an ionic liquid with special physical and chemical properties to fill a cylinder and compress gas under the drive of a hydraulic piston. Ionic liquids are almost incompressible, do not dissolve or contaminate hydrogen gas, and have good lubrication and cooling properties. The motor drives the hydraulic piston, which pushes the ionic liquid. The ionic liquid then acts on the hydrogen gas, achieving compression and transportation of the hydrogen gas.
Low temperature liquid pump hydrogen compressor: Utilizing the low-temperature characteristics of low-temperature liquids (such as liquid nitrogen), the hydrogen is first cooled to a low-temperature state, reducing its volume and increasing its density. Then, the low-temperature hydrogen is pressurized by a liquid pump, and finally the pressurized hydrogen is heated to room temperature, thereby achieving an increase in hydrogen pressure.
Metal hydride compressor: Based on the characteristic that certain metals or alloys can undergo reversible reactions with hydrogen to form metal hydrides. At lower pressures, metals or alloys absorb hydrogen gas to form metal hydrides, where the hydrogen gas is stored in the metal lattice; When metal hydride is heated or the surrounding pressure is reduced, the metal hydride decomposes, releasing high-pressure hydrogen gas, thereby achieving hydrogen compression.
Electrochemical hydrogen compressor: using electrochemical principles to compress hydrogen gas through the reverse process of an electrolytic cell or fuel cell. In the electrolytic cell mode, hydrogen gas is introduced into the cathode chamber. Under the action of an electric field, hydrogen ions migrate through the electrolyte membrane to the anode chamber, and electrons flow from the cathode to the anode through an external circuit. They recombine into hydrogen gas in the anode chamber. Due to the higher pressure in the anode chamber than in the cathode chamber, hydrogen gas is compressed; In the reverse process mode of fuel cells, the principle is similar, both using electrode reactions and ion migration to achieve hydrogen gas pressurization.
Adsorption type compressor: uses the adsorption and desorption characteristics of adsorbents for hydrogen gas to achieve compression. Under low pressure, the adsorbent adsorbs hydrogen gas; When heating or reducing the pressure of the adsorbent, the adsorbent desorbs hydrogen gas. During the desorption process, the density of hydrogen molecules in the pores of the adsorbent increases, resulting in higher pressure hydrogen gas, which achieves compression and transportation of hydrogen gas.
The following are the advantages and disadvantages of different types of hydrogen compressors:
Reciprocating hydrogen compressor
Advantages: Mature technology, high reliability; Large pressure ratios can be achieved through multi-stage compression, suitable for new hydrogen compression; Not sensitive to the molecular weight of compressed gas; Wide range of work pressure and flow rate; Easy to control, capable of multiple control modes from manual to automatic.
Disadvantages: Large size and large footprint; There are vulnerable parts such as piston rings, which result in high maintenance costs; High vibration and noise during operation; During the compression process, hydrogen gas is prone to leakage through the piston ring, resulting in a decrease in volumetric efficiency.
Centrifugal hydrogen compressor
Advantages: High flow rate, suitable for large-scale hydrogen compression and transportation; High operational efficiency, especially under high flow conditions; Smooth operation with minimal vibration and noise; No lubrication system (dry gas seal) is required, avoiding contamination of hydrogen gas by lubricating oil.
Disadvantages: It has certain requirements for the molecular weight and density of the gas, and is not suitable for the compression of low molecular weight hydrogen gas; The compression ratio is relatively low, making it less suitable for high-pressure hydrogen compression; High equipment investment and operating costs; The cleanliness requirements for gases are high, otherwise it is easy to damage components such as impellers.
Diaphragm hydrogen compressor
Advantages: The use of membranes completely isolates oil and gas, ensuring gas purity and no pollution; Good sealing performance, suitable for compressing flammable and explosive dangerous gases; High compression ratio, easy to achieve low intake and high exhaust; Isothermal compression combined with integrated cooling results in low exhaust temperature.
Disadvantages: The dome shaped surface of the membrane head is a special profile, making it difficult to process; Difficult to adapt to frequent start stop working conditions; The price is higher than that of general piston compressors; The membrane is relatively easy to damage, and the installation process of the membrane requires a high level of worker experience; The exhaust volume is relatively small due to the high pressure ratio and the limitation of the chamber volume.
Liquid driven hydrogen compressor
Advantages: Simple structural principle, multi-level series and parallel compression, flexible layout; Easy to operate and control; The overall cost is relatively low.
Disadvantages: High sealing requirements, high possibility of hydrogen contamination; The sealing ring is prone to damage and aging, with a short replacement cycle and high maintenance costs; Single level compression is relatively low; The piston structure produces significant noise.
Ionic liquid compressor
Advantages: Simple principle; Without vulnerable parts such as piston rings and packing for piston compressors; High working frequency and small footprint; Ionic liquid ensures that hydrogen gas is pollution-free; Improve compression efficiency and reduce energy consumption.
Disadvantages: Due to high costs, manufacturing standards are different from those in China, and there are fewer applications in China; Ionic liquids and controllers are difficult to develop, expensive, and have average stability; The explosion-proof level does not meet the national standard.
Low temperature liquid pump hydrogen compressor
Advantages: It can achieve high pressure increase; The purity requirement for hydrogen is relatively low; No mechanical friction components during operation, high reliability, and low maintenance costs.
Disadvantages: Requires a low-temperature liquid supply system, which is complex; High energy consumption; It is sensitive to changes in environmental temperature and pressure, and its operational stability is affected.
Metal hydride compressor
Advantages: No vibration, no driving components; Easy to maintain and low cost; The quality and volume of the device are small; Low electricity consumption allows for the utilization of waste heat; Hydrogen storage alloys have fast hydrogen absorption speed, short boost time, and can achieve high pressure using multi-stage design.
Disadvantages: The hydrogen absorption and desorption reaction rate of metal hydrides is limited, resulting in relatively low working efficiency of compressors; External heating and cooling devices are required to control the reaction temperature, and the system is relatively complex; The cost of metal hydride materials is relatively high, and performance degradation may occur after long-term use.
Electrochemical hydrogen compressor
Advantages: High compression efficiency; Can start at lower pressure without the need for large mechanical drive devices; The purity requirement for hydrogen is not high; There is no noise or vibration during operation.
Disadvantages: High cost of electrode materials and electrolytes; Stable power supply is required, and the electrolysis process consumes a large amount of energy; The lifespan and stability of equipment are limited by the performance of electrode materials and electrolytes; At present, the technology is not mature enough and there are few large-scale applications.
Adsorption type compressor
Advantages: Simple structure, low operating cost; Not sensitive to impurities in hydrogen gas; Can work under lower pressure; No lubrication system is required, avoiding contamination of hydrogen gas by lubricating oil.
Disadvantages: The adsorption capacity of the adsorbent is limited, resulting in a smaller displacement of the compressor; The adsorption and desorption processes require a certain amount of time and have low work efficiency; The adsorbent may experience a decrease in adsorption performance after long-term use and needs to be replaced regularly.
