1. Application of hydrogen refueling stations
Pressure requirement: Hydrogen refueling stations need to compress hydrogen gas to a very high pressure to meet the filling needs of fuel cell vehicle hydrogen storage tanks. Usually, hydrogen needs to be compressed to 3570MPa or even higher. This requires Hydrogen Compressors to have high pressure ratio compression capability, which can stably increase hydrogen pressure in multi-stage compression.
Flow requirements: The flow rate of the hydrogen compressor at the hydrogen refueling station should be determined based on the size of the station and the number of service vehicles. For small hydrogen refueling stations, the flow rate of the hydrogen compressor may be around 1050kg/h; Large hydrogen refueling stations may require a flow rate of 200, 500 kg/h or even higher. Therefore, the flow regulation range of the compressor should be wide to adapt to different hydrogenation needs.
Purity requirement: Due to the extremely high requirement for hydrogen purity in fuel cells (generally requiring hydrogen purity of 99.97% or above), the hydrogen compressor must ensure that no impurities are introduced during the compression process. This requires the compressor to have good sealing performance to prevent impurities such as lubricating oil and air from entering the hydrogen gas. For example, diaphragm hydrogen compressors have advantages in this regard, as they isolate hydrogen from other components through membranes, effectively ensuring the purity of hydrogen.
Safety requirements: Hydrogen refueling stations store and process large amounts of high-pressure hydrogen gas, and safety is crucial. Hydrogen compressors need to have comprehensive safety protection devices, such as overpressure protection, temperature protection, leak detection, etc. When the pressure or temperature exceeds the set value, the compressor can automatically shut down; Once a hydrogen leak is detected, it can promptly sound an alarm and take corresponding safety measures.
2. Application in the chemical industry
Pressure and flow requirements: In chemical production processes such as hydrocracking and ammonia synthesis, the pressure and flow of hydrogen compressors should be determined according to specific chemical reaction requirements. For example, in a hydrocracking unit, the hydrogen compressor may need to compress hydrogen to around 1020MPa, and the flow rate can range from several hundred cubic meters per hour to tens of thousands of cubic meters per hour depending on the production scale of the unit. Moreover, the demand for hydrogen in the chemical production process is usually continuous and stable, so the compressor needs to be able to operate stably for a long time under certain pressure and flow rate.
Corrosion resistance requirements: In chemical production, hydrogen may contain some corrosive impurities such as hydrogen sulfide, hydrogen chloride, etc. Therefore, the material of the hydrogen compressor should have good corrosion resistance, or the key components inside the compressor (such as cylinders, pistons, valves, etc.) should be treated with anti-corrosion. For example, the key components of the compressor are made of corrosion-resistant materials such as stainless steel to prevent corrosion damage and extend the service life of the compressor.
Reliability requirement: Chemical production equipment usually operates continuously. Once the hydrogen compressor fails, it may cause the entire production process to be interrupted, resulting in huge economic losses. Therefore, hydrogen compressors need to have high reliability, their design and manufacturing must comply with strict quality standards, and they must have a comprehensive maintenance and repair support system that can quickly repair faults and reduce downtime.
3. Application of hydrogen energy storage
Pressure requirements: Hydrogen energy storage systems typically require compressing hydrogen to a higher pressure for storage, in order to increase the energy density of hydrogen. Generally, hydrogen needs to be compressed to 1030 MPa or even higher. The pressure control accuracy of the compressor is also important, as precise control of the hydrogen storage pressure is required during the energy storage process to ensure the safe and efficient operation of the energy storage system.
Efficiency requirement: During the charging and discharging process of hydrogen energy storage, the efficiency of the compressor directly affects the energy conversion efficiency of the energy storage system. Due to the potential large scale of energy storage systems and the high energy consumption of compressors, it is required that hydrogen compressors maintain high compression efficiency across a wide pressure range and different flow rates. For example, using advanced compression technology and optimized compressor structures, such as centrifugal compressors operating efficiently at high flow rates, or reciprocating compressors improving efficiency through multi-stage compression, to reduce energy consumption.
Cycle life requirement: The hydrogen energy storage system requires frequent compression and release of hydrogen, which requires the hydrogen compressor to withstand frequent start stop and pressure changes. The key components of the compressor, such as pistons and valves, should have sufficient fatigue strength and wear resistance to ensure normal operation after multiple cycles and extend the cycle life of the compressor.
4. Laboratories and small-scale applications
Flexibility requirement: In laboratory and small-scale hydrogen application scenarios, the amount and pressure requirements of hydrogen may frequently change. For example, in laboratory experimental equipment, hydrogen gas may need to be compressed to different pressures (ranging from a few MPa to several tens of MPa) according to different experimental requirements, and the flow rate of hydrogen gas is also relatively small. Therefore, hydrogen compressors need to have flexible pressure and flow regulation functions, and be easy to operate.
Compact requirements: Due to limited laboratory space, small-scale application scenarios often have certain requirements for equipment volume. So, hydrogen compressors should be as compact as possible, occupying minimal space, and easy to install and move. For example, some small reciprocating hydrogen compressors or adsorption hydrogen compressors have relatively simple and compact structures, making them suitable for use in laboratories and small-scale locations.
Low noise and low maintenance requirements: In laboratory and other environments, there are strict requirements for equipment noise. Hydrogen compressors should minimize noise and vibration during operation. In addition, as these application scenarios may not have professional maintenance personnel, the maintenance of the compressor should be simple and easy, such as easy replacement of components and easy diagnosis of faults.
Types of hydrogen compressors suitable for different applications
1. Application of hydrogen refueling stations
Diaphragm hydrogen compressor:
Due to the extremely high requirement for hydrogen purity in fuel cell vehicles (usually above 99.97%), a diaphragm compressor completely isolates hydrogen from other substances such as lubricating oil through a diaphragm, effectively ensuring hydrogen purity and avoiding impurities from damaging the fuel cell.
It can achieve a high compression ratio and lift hydrogen gas from a lower pressure to 3570MPa or even higher, meeting the filling requirements of on-board hydrogen storage tanks. Moreover, its compression process is relatively stable, and the flow regulation range can also adapt to different hydrogenation needs of the refueling station.
Ionic liquid compressor:
Ionic liquid compressors also have excellent performance in ensuring hydrogen purity. Ionic liquids are almost incompressible and do not dissolve or contaminate hydrogen gas, providing pollution-free high-pressure hydrogen gas.
This type of compressor has a high operating frequency and small footprint, making it suitable for places with certain spatial layout requirements such as hydrogen refueling stations. It can effectively improve compression efficiency and reduce energy consumption during the filling process of high-pressure hydrogen gas.
2. Application in the chemical industry
Reciprocating hydrogen compressor:
In chemical production, processes such as hydrocracking and ammonia synthesis require relatively stable pressure and flow rate of hydrogen gas. The reciprocating compressor compresses by the reciprocating motion of the piston in the cylinder, and can achieve high pressure through multi-stage compression, which can meet the pressure demand of about 1020MPa in chemical production.
It has a wide range of adaptability to flow rate and can flexibly adjust the hydrogen flow rate according to the production scale of chemical plants, ranging from several hundred cubic meters per hour to tens of thousands of cubic meters per hour. Moreover, for the corrosive impurities that hydrogen gas may contain in chemical production, reciprocating compressors can enhance their corrosion resistance by selecting suitable materials to make key components such as cylinders, pistons, and valves.
Centrifugal hydrogen compressor:
For large-scale chemical production, centrifugal compressors are a good choice when there is a huge demand for hydrogen flow (such as in large synthetic ammonia plants). It has a large flow rate and can continuously and efficiently process large amounts of hydrogen, making the hydrogen supply in the chemical production process more stable.
Centrifugal compressors can operate normally when processing hydrogen gas containing certain impurities, as long as appropriate filtering devices are installed at the inlet. At the same time, it operates efficiently under high flow conditions and can effectively reduce energy consumption, making it suitable for cost sensitive applications in the chemical industry.
3. Application of hydrogen energy storage
Metal hydride compressor:
The hydrogen energy storage system requires frequent compression and release of hydrogen gas. Metal hydride compressors are based on reversible reactions between metals or alloys and hydrogen gas, without complex mechanical moving parts, and can withstand frequent start stop and pressure changes.
It can use waste heat and other energy to work, which to some extent reduces energy consumption. And through multi-stage reactions, higher pressures can be achieved to meet the pressure requirements of hydrogen energy storage systems at 1030 MPa or even higher.
Adsorption type compressor:
The adsorption compressor has a simple structure and energy-saving advantages in low-pressure and low flow conditions of hydrogen energy storage systems. It utilizes the adsorption and desorption characteristics of adsorbents for hydrogen gas to achieve compression, and can adapt to changes in pressure and flow rate during the hydrogen gas charging and discharging cycle.
It has low operating costs and is insensitive to impurities in hydrogen gas, making it suitable for use in environments such as hydrogen energy storage systems where impurities may exist. It does not require lubrication systems, avoiding contamination of hydrogen gas by lubricating oil.
4. Laboratories and small-scale applications
Small reciprocating hydrogen compressor:
The amount and pressure requirements of hydrogen in laboratory and small-scale application scenarios often change, and small reciprocating compressors are flexible to operate. It can adjust the pressure from a few MPa to tens of MPa at low flow rates by adjusting the piston stroke, speed, or the number of working cylinders, meeting the diverse needs of experimental devices.
This type of compressor has a relatively simple structure, a relatively low price, and is easy to install and maintain. It is suitable for use in places with limited space and certain cost requirements such as laboratories.
Adsorption hydrogen compressor:
Adsorption compressors have unique advantages in laboratory and small-scale applications. It has a small and compact size, occupies less space, and operates without mechanical friction components, resulting in low noise and meeting the laboratory's requirements for quiet operation of equipment.
It can work at lower pressures and adapt well to the small flow and low pressure requirements of hydrogen in small-scale hydrogen applications. In some experimental scenarios where purity requirements are not extremely high, it can also play a good role due to its insensitivity to hydrogen impurities.
