Contrast Analysis of Centrifugal Air Compressor and Screw Air Compressor?

Contrast Analysis of Centrifugal Air Compressor and Screw Air Compressor? Air compressor is the core power equipment of industrial production, among which screw type and centrifugal type air compressor are widely used. The two belong to the volume-type and speed-type compression categories. There are significant differences in the core working mechanism, operating efficiency, and adaptability to working conditions, which directly affect the energy consumption cost and production stability of enterprises. In this article, Turbo-Tech compressors will conduct a special comparison from their working principles, core differences, advantages and disadvantages, operating efficiency and applicable scenarios, and provide a reference for industrial equipment selection.
Contrast Analysis of Centrifugal Air Compressor and Screw Air Compressor?
Ⅰ. Comparison of core working principles
1. Screw air compressor (volumetric compression)
The core compression mechanism of the screw air compressor is a pair of precision meshing yin and yang rotors, relying on the periodic change of volume to achieve gas compression, which is a forced gas transmission equipment. The working process is divided into three stages: continuous suction, compression, and exhaust: when the rotor rotates, the cogging volume gradually increases to complete air suction; As the rotor meshes and rotates, the volume of the closed cog is reduced, and the internal air is boosted; Then the high-pressure gas is completed at the exhaust end, and the whole process is compressed continuously without pulsation and the airflow is stable.
The mainstream models on the market are divided into two categories: oil injection screw and oil-free screw: oil injection model realizes sealing, lubrication and cooling through oil injection, with high cost performance and wide application; The oil-free model adopts rotor coating and synchronous gear transmission, the compression cavity is oil-free, and clean compressed air can be produced.
2. Centrifugal air compressor (velocity compression)
The centrifugal air compressor has no meshing compression components, and relies on the energy conversion of kinetic energy and static pressure energy to complete compression. The core components are high-speed impellers, diffusers and volutes. The working logic is: the motor drives the impellers to rotate at high speed, converting mechanical energy into air kinetic energy, and making the airflow flow at high speed; High-speed air flow enters the fixed diffuser channel, the flow rate drops sharply and the pressure rises, completing the conversion of kinetic energy to static pressure energy, and multi-stage impellers in series can realize high-pressure and large-flow gas supply.
Its compression characteristic is passive speed increase and pressure increase, and the gas transmission volume is strongly related to the impeller speed and inlet working conditions. The core feature is large flow rate and continuous and stable gas supply.
Ⅱ. Analysis of core performance differences and advantages and disadvantages
1. Differences in structure and operating characteristics
The screw air compressor has a compact structure and simple components. The core moving part is only a pair of rotors. The equipment is small in size and convenient to install, and the vibration and noise are low. There is no special high-precision requirement for the installation site.
The structure of centrifugal air compressor is precise and complex, including high-speed impellers, bearings, cooling systems, anti-surge systems, etc. The equipment is large in size, and there are requirements for the smoothness and cleanliness of the installation base storage site.
2. Comparison of core advantages and disadvantages
Screw air compressor
Advantages and disadvantages
Advantages:
First, the adaptability of working conditions is extremely strong. 　　The frequency conversion model can steplessly adjust the gas volume in the 30%-load range, and the energy consumption attenuates smoothly under small gas volume fluctuations;
Second, the exhaust pressure is stable, the ability to resist pipe network pressure fluctuations is strong, and it is not easy to cause working condition failures;
Third, the cost performance is outstanding under low pressure and small flow conditions.
Cons:
Under the condition of large flow and high load, the unit gas volume ratio power is high, and the overall energy efficiency is not as good as that of centrifugal air compressor models;
The gas produced by the fuel injection model contains a trace amount of oil, and it needs to be equipped with precision purification equipment;
The large displacement of a single equipment is limited, and it is impossible to provide super-large-scale gas supply demand.
centrifugal air compressor
Advantages and disadvantages
Advantages:
The energy efficiency of rated working conditions is outstanding, the unit energy consumption is much lower than that of screw machines during large flow and full load operation, and the energy-saving benefits of operation are remarkable;
Pure mechanical high-speed compression has no oil pollution, and can directly produce oil-free clean compressed air, suitable for high-end process scenarios;
A single equipment has large displacement and stable gas supply, which is suitable for large-scale continuous production;
The core components are wear-resistant, the whole machine has a long service life, and the operation and maintenance stability is excellent.
Cons:
There is an inherent surge risk. If the gas volume is lower than the critical value, the airflow will fluctuate and the equipment will shake, and the unit will be damaged in severe cases; Overall no cost and energy efficiency advantages under small flow conditions.
Ⅲ. In-depth comparison of operating efficiency
1. Rated operating efficiency
Under full-load rated conditions, centrifugal air compressors have significant energy efficiency advantages, lower power than high-flow scenarios, and higher energy efficiency than variable frequency screw machines. The energy efficiency of screw air compressor is stable under small flow rate and rated load, but the upper limit is lower than that of centrifugal air compressor.
2. Adjusting efficiency under off-design conditions
Variable load conditions are the core scenarios for the efficiency differentiation between the two. The frequency conversion screw machine is highly adaptable, and can operate with high energy efficiency in the 30%-load range, and the energy consumption control effect in gas volume fluctuations and intermittent production scenarios is excellent. Centrifugal air compressors need to adjust or vent the inlet guide vane to stabilize the pressure.
3. Comprehensive energy consumption characteristics
Stable full-load, large-flow continuous production: centrifugal air compressors have lower comprehensive energy consumption, and energy-saving benefits can cover high procurement costs;
Large gas volume fluctuations, intermittent production, and small flow conditions: the energy consumption of screw air compressors is more controllable, and the comprehensive operating cost is far better than that of centrifugal air compressors.
Ⅳ. Accurate distinction of applicable scenarios
Adaptation Scenario of Screw Air Compressor
1. In the small and medium flow gas supply scenario, the gas consumption of a single station is ≤ 20 m3/min;
2. Working conditions of large fluctuations in production load, intermittent production, start and stop;
3. Ordinary industrial gas supply scenarios have general requirements for air cleanliness, and can be equipped with purification equipment to remove oil;
4. Small and medium-sized enterprises with limited site conditions, moderate budget, and pursuit of low operation and maintenance costs.
Centrifugal air compressor adaptation scene
1. In the scene of large-scale continuous gas supply, the gas consumption of a single station is ≥ 20 m3/min, and the production is continuous at full load for 24 hours;
2. High-end process scenarios, such as medicine, electronics, and precision manufacturing, require oil-free, ultra-clean compressed air;
3. Large-scale chemical, steel, electric power and other heavy industries have stable production, a large energy consumption base, and pursue energy-saving benefits;
4. Core production lines that have extremely high requirements on the stability and continuity of gas supply and do not allow fluctuations in working conditions to shut down.
The above is the introduction of “Comparative Analysis of Centrifugal Air Compressor and Screw Air Compressor”. There is no clear pros and cons between Screw Air Compressor and Centrifugal Air Compressor. Screw Air Compressor is better at low cost and adapts to variable working conditions. It is a general choice for small-scale and fluctuating working conditions; Centrifugal air compressors are high in energy efficiency, large flow rate, oil-free and clean under rated working conditions. They are energy-saving and excellent for large-scale continuous production. The selection of enterprises needs to combine their own gas consumption, load fluctuation law, production continuity and budget to match the corresponding models., to achieve more optimized energy consumption and operation and maintenance costs.