1. Process parameter requirements
Pressure and flow rate
Pressure range: Different application scenarios have significant differences in hydrogen pressure requirements. If the hydrogen refueling station needs to compress hydrogen gas to 35 70MPa for refueling fuel cell vehicles; The chemical synthesis of ammonia process usually requires a hydrogen pressure of 10-30 MPa; And some laboratory studies may only require a few MPa of pressure. The selection of compressors should ensure that their working pressure range can meet specific process requirements.
Flow requirements: Determine flow requirements based on the scale of the application and the rate of hydrogen consumption. Large chemical plants may require thousands of cubic meters of hydrogen flow per hour, while small experimental equipment may only require a few cubic meters per hour. And, it is necessary to consider whether the flow needs to be stably supplied or whether it needs to be adjusted within a certain range. For example, continuous chemical production requires a stable hydrogen flow rate, while experimental research scenarios may require flexible adjustment of flow rate.
Hydrogen purity
High purity application: In the field of fuel cells, hydrogen purity requirements are extremely high, generally reaching 99.97% or more, to prevent impurities from poisoning the fuel cell electrodes. For this situation, like a diaphragm Hydrogen Compressor, it can effectively prevent impurities from entering the hydrogen gas through a special structure (such as diaphragm isolation), ensuring high purity.
Application with lower purity requirements: In some chemical reactions, if hydrogen is only used as a protective gas or auxiliary reaction gas, the purity requirements are relatively low. When selecting, the purity restrictions can be appropriately relaxed, but it may still be necessary to consider how to prevent impurities from having adverse effects on the process.
temperature and humidity
Temperature effect: The temperature of hydrogen gas can affect the performance of the compressor. High temperature hydrogen gas can reduce the efficiency of the compressor, increase energy consumption, and may damage components. For example, in the process of recovering hydrogen from high-temperature chemical reaction exhaust gas and compressing it, it is necessary to choose a compressor that can withstand higher intake temperatures or install a cooling device at the intake.
Humidity control: If the humidity of hydrogen is high, condensation water may form inside the compressor, causing rusting, corrosion, or affecting the compression performance of the gas. So, for hydrogen with high humidity, it is necessary to consider installing a drying device before the compressor or choosing a compressor with drainage function.
2. Gas characteristic factors
Corrosivity: If hydrogen contains corrosive impurities (such as hydrogen sulfide, hydrogen chloride, etc.), the material of the compressor must have good corrosion resistance. Key components such as cylinders, pistons, valves, etc. can be made of corrosion-resistant materials such as stainless steel and special alloys, or treated with anti-corrosion coatings to prevent corrosion damage.
Flammability and explosion-proof requirements: Hydrogen is a flammable and explosive gas, and the explosion-proof performance of the compressor should be considered when selecting. For example, electrical components such as motors should meet explosion-proof standards, and compressors should have good sealing performance to prevent hydrogen leakage and the formation of flammable mixtures. At the same time, it is necessary to consider whether the operating environment of the compressor meets explosion-proof requirements, such as good ventilation and no open flames.
3. Reliability and maintainability
Continuous operation capability: In industrial production, such as chemical and metallurgical industries, the production process is usually continuous, and hydrogen compressors require high reliability and continuous operation capability. Centrifugal compressors have a relatively simple structure, without easily worn piston components, and can operate stably for a long time under normal maintenance; Although reciprocating compressors have components that are prone to wear, they can still meet the requirements for continuous operation through reasonable design and maintenance measures. At the same time, it is necessary to consider whether a backup compressor or redundant design is needed.
Maintenance difficulty and cost:
Vulnerable parts and maintenance cycle: The vulnerable parts of different types of compressors are different. The reciprocating compressor has vulnerable parts such as piston rings and air valves, which need to be replaced regularly; The impeller and other components of a centrifugal compressor are not easily damaged during normal operation, but once damaged, it is difficult to repair. The maintenance cost should be evaluated based on the vulnerable parts and maintenance cycle of the compressor.
Convenience of maintenance: Select compressors with components that are easy to disassemble and install, making it convenient for maintenance personnel to inspect, repair, and replace. At the same time, it is also necessary to consider whether there is professional technical support and maintenance services, especially for some complex compressors.
4. Energy efficiency and operating costs
Energy consumption: The energy efficiency of compressors directly affects operating costs. Centrifugal compressors have lower energy consumption under high flow and medium low pressure conditions; Reciprocating compressors may be more energy-efficient under low flow and high pressure conditions. Choose a compressor with high energy efficiency based on the actual pressure and flow conditions of the application. At the same time, the impact of the compressor's driving method (such as motor drive, steam drive, etc.) on energy efficiency should also be considered.
Comprehensive operating costs: In addition to energy costs, operating costs also include equipment depreciation, maintenance, lubricants, and other consumables costs. When selecting, it is necessary to comprehensively consider these factors and calculate the full lifecycle cost of the compressor. For example, although a compressor has a lower purchase price, if its energy efficiency is low and maintenance costs are high, it may not be the optimal choice in the long run.
5. Space and installation conditions
Space limitations: In laboratories, small hydrogen refueling stations, and other places where space is limited, it is necessary to choose compressors with small volume and footprint. For example, adsorption hydrogen compressors or small reciprocating hydrogen compressors have compact structures and are suitable for use in space limited environments.
Installation requirements: Different types of compressors have different installation requirements. Large centrifugal compressors require a sturdy foundation and a large installation space, and have high requirements for installation accuracy; Small compressors may be relatively easy to install. At the same time, it is necessary to consider the ventilation, drainage, explosion-proof and other conditions of the installation environment to ensure that the compressor can operate safely and stably.
6. Device compatibility and scalability
Compatibility with existing systems: If adding a compressor to an existing hydrogen system, ensure that the new compressor is compatible with existing pipelines, valves, control systems, and other equipment. For example, the inlet and outlet diameters and connection methods of the compressor should match the existing pipelines, and the type and interface of the control signal should be compatible with the control system.
Scalability: Consider possible changes in future application scenarios, such as increased demand for hydrogen flow or pressure. Choose compressors with scalability, such as increasing the number of stages or parallel compressors, to meet future higher requirements.
