Mysterious Veil of Centrifugal Air Compressor

Release time：2023-08-10    Click：144

A: Hello, please. I told you about the flow and pressure of the centrifugal air compressor required by the owner before. Why didn't you give me a plan?

T: Hello, Mr. A, let me know the situation first.

A: Well, my customer needs to purchase equipment. I'll contact you. At the beginning, I told the customer about his needs, but you didn't give me a plan and asked me a lot of questions.

T: OK. Can I know what parameters you have told me and what questions you have been asked?

A: I told you the gas volume and pressure required by your customers at the beginning. What altitude and intake pressure do you need to ask; Gauge pressure and absolute pressure; Exhaust temperature or something?

T: Listen to me. The customer's geographical environment is very important for compressor selection. Altitude causes some models to be applicable at low altitude, but not at high altitude. The atmospheric pressure is different at different altitudes, and different atmospheric pressure will lead to the change of interstage pressure ratio of the compressor. At the same time, different altitudes also mean different intake air temperature, humidity and other conditions. Therefore, it is necessary to understand the customer's geographical environment, annual average temperature and humidity, so as to accurately calculate and give the selection scheme.

A: Well, even so, after I replied to these parameters, you still haven't given me the plan immediately.

T: To ensure the optimal efficiency of the equipment we deliver, each of our equipment is customized. We will use the pneumatic analysis software to design each unit separately according to the customer's requirements and actual working conditions to ensure the accuracy and efficiency of the unit. Therefore, after collecting the necessary information (including geographical conditions, power supply conditions, voltage requirements, compression medium, exhaust temperature requirements, etc.), our staff will summarize these information to the engineering and technical personnel, who will conduct aerodynamic analysis and provide the selection scheme. Therefore, it takes a certain time to complete the selection process and issue the scheme.

A: Why is the centrifugal air compressor so troublesome? I might as well change it to a screw air compressor.

T: This requires us to talk about the difference between centrifugal air compressor and screw air compressor.

A: Is the selection of centrifugal air compressor so troublesome? Then I might as well use a screw air compressor!

T: Let's talk about the difference between centrifugal air compressor and screw air compressor.

The basic composition of centrifugal air compressor and screw air compressor is similar, which are composed of drive motor, transmission system, head, cooling system, lubrication system, sealing system, regulating system and control system.

However, due to their different principles, there are still many differences between them.

Advantages and disadvantages of centrifugal air compressor:

The centrifugal air compressor is a speed type air compressor, which has the following advantages:

1. The exhaust volume is large, the exhaust is uniform, and the air flow has no pulse.

2. The compression process tends to isothermal compression, and the overall efficiency is high.

3. The unit lubrication system and air circuit system operate independently to ensure that the compressed medium is 100% oil-free.

4. The sealing effect is good and there are few leaks.

5. Flat performance curve, stable and efficient within the operating range.

6. The whole machine is controlled by Siemens PLC, which is easy to realize industrial automation and unattended.

7. Less wearing parts, less maintenance and long operation cycle.

But at the same time, the centrifugal air compressor also has shortcomings:

1. The large-scale equipment puts forward higher requirements for the power distribution and cooling water system of the plant.

2. The cost of the equipment is higher than that of the screw machine, and the one-time purchase cost increases. However, with the progress of localization, the price has been greatly improved.

Advantages and disadvantages of screw air compressor:

As a positive displacement compressor, screw air compressor has the following advantages:

1. The screw air compressor is easy to operate and does not have high requirements for operators. It is suitable for small flow range applications.

2. Screw air compressor has the characteristics of forced gas transmission. The volume flow is almost not affected by the exhaust pressure, and it can maintain high efficiency in a wide range. It is suitable for various working conditions without any change in the air compressor structure.

Main disadvantages of screw air compressor:

1. For the oil injection screw machine, the compressed medium contains oil, which is suitable for the occasions where the requirements for gas quality are not high.

2. The amount of maintenance is large and the maintenance cost is high. Usually, maintenance is required once every 4000-6000 hours.

3. It is not suitable for large exhaust volume. Generally, for users with large gas volume, multiple screw machines are required, which cover a large area and have high operation and maintenance costs.

Summary: Screw air compressor has large maintenance amount, high operation cost and poor energy saving compared with centrifugal air compressor. The overall operation of the centrifugal air compressor is reliable and stable. For example, the 120 m3 centrifugal air compressor can save more than 15% energy than two 60 m3 screws. The air inlet filter element is self-cleaning and can be maintained once a year.

A: I still don't understand what you said. Do you mean that centrifugal air compressor is more energy-saving and efficient than screw air compressor? Although the efficiency of centrifugal compressor will be better, is the price of centrifugal compressor expensive?

T: Yes, many customers have concerns about this. In terms of general screw air compressor, in the whole life cycle of the equipment, the purchase cost of the equipment accounts for about 10% of all costs, the maintenance cost is about 20%, and the use cost, that is, the electricity cost, accounts for about 70%. As far as the cost of the whole equipment life cycle is concerned, although the purchase cost of our centrifugal compressor will be slightly higher than that of the screw air compressor, the centrifugal compressor is characterized by fewer vulnerable parts, less maintenance and long operation cycle, which greatly reduces the proportion of maintenance costs in the whole life cycle. At the same time, the high efficiency and energy saving of the centrifugal compressor will also save customers considerable electricity costs. It can be said that the horse power is known from afar, and the benefits will be seen over time.

A: That's good. It can help customers save a lot. Through your just series of explanations, I have learned a lot about centrifugal compressors. I used to think that the centrifugal compressor was mysterious, but now it seems that the application scenario is quite broad. Can you explain to me which industries our centrifugal compressor application will have advantages?

T: You are right. With the development of China's industrialization, centrifugal compressors are increasingly favored by users because of their high operating efficiency and pure oil-free compressed air. Especially in recent years, due to the development of chemical industry, various large-scale chemical plants, such as ethylene cracking, methanol synthesis ethylene epoxidation, etc., and the establishment of ten million ton refinery, the high pressure and high temperature steam generated by the recovered waste heat has created good conditions for the application of centrifugal compressor. So at present, centrifugal compressor has become the key equipment for compressing and transporting various gases in chemical production. In addition to playing an extremely important role in the production of ethylene, propylene and butadiene, which are important basic chemical raw materials for synthetic plastics, fibers and rubber, centrifugal compressors have also become key equipment in other fields, such as petroleum refining, refrigeration and other industries. With the continuous expansion of production scale, a large amount of high-pressure and high-temperature waste heat generated in the production process needs to be recycled, which also provides favorable conditions for the utilization of centrifugal compressors. In addition, it is believed that air separation, steelmaking, semiconductor, medicine, fermentation and other industries are also the main application industries of centrifugal compressors, which can be continuously concerned.

A: Great. During the explanation, I saw the vast market of centrifugal compressor, which is promising!

T: What are you waiting for? Welcome to our factory of Turbo-Tech Compressor Wuxi Co., Ltd. Seeing is believing!