Starting from the petrochemical industry, take a look at the reasons why users waste compressed air

Starting from the petrochemical industry, take a look at the reasons why users waste compressed air

1.How high is the cost of compressed air?

Air comes from the atmosphere, inexhaustible and inexhaustible. Many people at the industrial site believe that the use of compressed air does not require cost, and their understanding of the cost of compressed air is extremely weak, which is a major cause of on-site waste.

　　The energy consumption index of industrial compressors is usually expressed by "specific energy".

　　The specific energy index indicates the average power consumption required to output a unit volume of compressed air: kWh/m3 (ANR). This index is in the range of 0.08～0.12kWh/m3(ANR) when the compressor output pressure is 0.7MPa(G). The smaller the value, the higher the efficiency.

　　The specific energy of the compressor varies with the compressor and output pressure. For example, if the electricity cost per kilowatt-hour of industrial electricity in most parts of our country is calculated at 0.6 yuan, the electricity cost for the production of 1m3 (ANR) compressed air is 4.8 cents to 7.2 cents.

　　 In addition to electricity costs, compressed air manufacturing costs include compressor lubricants, regular maintenance and equipment depreciation.

　　Take a medium-sized screw compressor with an annual working time of 4,000 hours as an example. The cost of this part and the electricity bill account for 19% and 81% respectively. If this part of the cost is also included, the actual manufacturing cost of 1m3 (ANR) compressed air is 6 cents to 9 cents.

　　 From this point of view, compressed air is not cheap. Establishing a sense of compressed air cost is the first step in pneumatic energy saving.

　　 2. Analysis of the status quo of high energy consumption in the petrochemical industry

　　 (1) Higher equipment energy consumption

　　 The petrochemical industry is not only a major energy producer but also a major energy consumer. Petroleum processing consumes a lot of energy. Among them, equipment energy consumption is the main component of the energy consumption of refining and chemical plants.

According to the statistics of Sinopec in 2005, the total energy consumption of Sinopec in 2005 was approximately 10.2058 million tons of standard oil. The fuel oil, fuel gas, electricity consumption, and steam converted from equipment consumption accounted for 67.84%, of which electricity consumption accounted for 18.44%. Close to 1.877 million tons of standard oil.

　　 Electricity is mainly consumed by moving equipment, such as pumps, fans, compressors, etc., and is used to transport and separate various media.

　　 In general, equipment energy consumption accounts for about 70% of the energy consumption of refining and chemical plants. Improving the energy efficiency of equipment and equipment systems is one of the main ways for petrochemical companies to save energy and reduce emissions.

　　 (2) Analysis of compressor energy consumption

　　Take the compressor as an example, the higher energy consumption of equipment is mainly manifested in the following aspects:

　　1. Some compressors deviate from design conditions

　　According to the calculation of the efficiency of a 6000V compressor in a petrochemical refining division, the average motor load rate of the compressor is 77.3%, which is close to the lower limit of 75%, and some even only 41%. The compressor operating load deviates from the design conditions, and the power load rate needs to be improved.

　　2. The process compressor lacks energy efficiency evaluation methods

　　 General power air compressor, complete product standards, test methods, and energy efficiency standards. However, the energy-saving monitoring method standard was promulgated and implemented in 1996 and should be revised according to the current situation.

　　 Process compressors lack energy efficiency assessment standards. Due to the wide variety and different types of process compressors, most of them have high power and are difficult to monitor. At present, there is still a lack of energy efficiency assessment standards, and there are few energy efficiency data available, which makes it difficult to judge whether the compressor performance is efficient.

Starting from the petrochemical industry, take a look at the reasons why users waste compressed air

　　3, variable load operation adjustment needs to be improved urgently

　　 The petrochemical industry often adopts the method of loading/unloading/return air adjustment for low-load operation, which consumes a lot of energy, and the adjusted air volume is equivalent to a complete waste of work done in this part.

　　 The low-load operation of the system also brings about the inefficient operation of compressed air post-processing equipment. When the matching is not completely reasonable, most of the equipment of the system is in a state of partial low load, and the low efficiency of energy use is very serious.

　　 96% of the energy consumption of the compressed air system is the electricity consumption of industrial compressors. The power consumption of industrial compressors in my country accounts for about 6% of the country's total power consumption.

　　 Three, the main problems of the current air compressor system in my country's gas companies

In the current compressed air system of Chinese users, energy waste is mainly manifested as large leakage, compressor configuration and operation only for pressure maintenance, unreasonable supply pressure, inefficient nozzles, waste of equipment air, and on-site workers use air Weak cost awareness and other issues.

　　 1. Compressed air leaks.

　　 On the issue of leakage, the amount of leakage in a factory usually accounts for 10%-30% of the air supply, and a poorly managed factory may even reach as high as 50%.

　　Sometimes there are 20,000 leaks in an automobile assembly workshop, and more than 90% of the leaks come from the aging or damage of parts in use.

Starting from the petrochemical industry, take a look at the reasons why users waste compressed air

　　2. On-site management personnel underestimate the loss caused by the leakage.

　　 For example, a leaking hole with a diameter of 1 mm in a trachea with a gas supply pressure of 0.7 MPa causes a loss of about 3,525 kilowatt-hours of electricity each year, which is almost equivalent to the annual household electricity consumption of two three-person households, as shown in Table 2.

　　 Strengthening the awareness of leakage loss, popularizing leakage detection and prevention methods are the current priorities. At present, some domestic companies are beginning to use ECOSO leak detectors and leak point scanners to check and plug leaks, and have achieved some results.

　　 3. Unreasonable configuration and operation of the compressor.

　　 Generally, in order to make the output pressure fluctuation small, many compressors adopt the suction valve adjustment method. This method still needs to consume 40% to 70% of the rated power when there is no gas supply, and the waste is more serious.

　　 For this reason, the introduction of frequency conversion control, number control, and the use of air compressor room energy-saving monitoring systems are very effective in reducing power.

　　 These are basically ignored in the actual operation of the factory, and guaranteeing pressure has become the w* requirement for compressor management in most factories.

　　4. High air supply pressure causes waste.

　　 Due to the uncertainty of pipeline pressure loss and the peak flow rate during equipment startup, the air supply pressure of the compressor is sometimes 0.2MPa～0.3MPa higher than the pressure required on site.

　　 And every time the terminal equipment increases by 0.1MPa, the power consumption of the compressor increases by 4% to 8%, resulting in a huge waste of energy.

　　 Sometimes the factory will increase the pressure of the gas supply for a few devices with high pressure requirements. This is extremely unreasonable and unwise in terms of energy use configuration.

　　 5. Irregular use of nozzles causes waste.

　　 nozzles are widely used in air-jet looms, finishing and machining of manufacturing and processing, and their air consumption can reach 50% of the total air supply in some industrial fields. Some on-site personnel can easily expand the nozzle orifice and increase the supply pressure without authorization in pursuit of large impact, resulting in a large waste of gas.

　　 6. Waste caused by other reasons.

　　 The phenomenon of unreasonable gas usage in pneumatic equipment is also more prominent, such as gas back pressure detection to determine whether the workpiece is stuck in place, vacuum generator gas supply, etc., there are non-working and uninterrupted gas supply phenomena.

　　Especially the use of gas used for stirring purposes such as chemical tanks, and shaping and inflation in tire manufacturing, etc., it is very common to use it from a high pressure of 0.7 MPa to a pressure of 0.1 MPa to 0.2 MPa, which is very wasteful.

　　 It is the prerequisite to rationalize the gas consumption of the equipment to grasp the actual pressure of the equipment from the process and the low gas consumption of z*. The average waste caused by the unreasonable use of equipment is estimated to be 20% of the air supply.

　　 All the above problems indicate that the current compressed air system is used to waste more air. The energy-saving transformation measures for gas equipment include:

　　Using a new type of pneumatic nozzle energy-saving device and pulsed air gun, the nozzle starts to blow when the workpiece is in place

　　The vacuum generator starts to supply air when the workpiece is in place

　　 High-energy-consuming pneumatic equipment changed to electric equipment (process mixing)

　　Large cylinder changed to two energy-saving cylinders

　　 The compressed air meets the low demand pressure of the equipment z*, and increases the suitable air storage tank to buffer the instantaneous large air consumption

　　 Use professional pneumatic equipment in specific industries, such as special throttle valves for shelling cylinders popularized in the electrolytic aluminum industry, etc.

　　 Therefore, as long as a detailed investigation of the compressed air system is carried out, the problem is clarified, and reasonable and effective energy-saving measures are taken, the entire system can achieve an energy-saving effect of 20% or more.

　　 Fourth, summary

　　 At the beginning of 2010, the author carried out energy-saving transformation of the pneumatic system of a certain wheel hub enterprise in China, which also achieved a system energy saving of more than 30%.

Starting from the petrochemical industry, take a look at the reasons why users waste compressed air

　　 If pneumatic energy-saving activities and pneumatic energy-saving technologies can be widely carried out in our country, it can save the country about 60 billion kilowatt-hours of electricity each year, equivalent to 36 billion yuan, which will have very considerable economic and social benefits for enterprises.

　　 Although this article starts with the petrochemical industry, energy consumption and energy-saving measures are the same:

Aiming at large and medium-sized enterprises in my country's chemical, chemical fiber, textile, automobile, rubber, electronic semiconductor, processing machinery and other manufacturing industries, with the purpose of reducing the energy consumption of air compressors, combining the characteristics of each industry to study feasible energy-saving technologies, and formulate a complete set of practices Effective, easy to implement, and the energy saving implementation process with a small payback period, industrialization, systematization, specificization, operability, visualization and further standardization of energy saving measures can respond to the energy saving of enterprises and the national energy saving goals Some contributions.