Application of Air Compressor Frequency Conversion Energy-saving Technology in Gas Transmission Pipeline Zhang Xudong 1 Hu Wei 1 Zhu Yanliang 2 Wang Peng 3 Ma Delong 3 (1. PetroChina Beijing Natural Gas Pipeline Co., Ltd.; 2. Daqing Oilfield Engineering Co., Ltd.; 3. China Petroleum Pipeline Company The characteristics of the inverter of Qinhuangdao Oil and Gas Branch Company, the necessity of the literary creation, the main content of the frequency conversion transformation and the comparative analysis of the energy saving benefits before and after the transformation. Take a certain gas station as an example, select the corresponding inverter according to the model of the air compressor, and install it in the air compressor room. After the transformation, the noise of the air compressor is reduced, the starting is stable, and the pressure control accuracy is improved. Through the 72h industrial frequency conversion test, the power saving effect is obvious, and it has very good social, economic and safety production benefits, and has the value of popularization and application. As the fourth energy source in the industrial field, compressed air has a wide range of applications in various industries. Air compressors (referred to as air compressors) are used in long-distance pipelines for pneumatic gas stations and gas storage, and are directly related to the safe operation of gas stations and gas storage. 1 Air compressor frequency conversion technology principle Compressor station and gas storage air compressor system are mainly Atlas GA22P air compressor and Ingersoll Rand ML45D air compressor, most of which are ready for operation, 24h operation. The models of the inverter are 132-丨丨, which are mainly selected according to the power of the air compressor. The working principle of the air compressor inverter n 1 is as follows: after the air compressor is combined with the high-efficiency energy-saving control system, the air compressor sends the start-stop signal and load signal (F*ID adjustment signal) to the inverter, and the inverter returns to the air compressor. The fault signal is simultaneously input to the inverter through the pressure transmitter to collect the pressure signal from the compressed air system, and the external pressure analog feedback of the P adjustment is loaded as the air compressor. The energy-efficient control system helps the user to achieve energy-saving control of the system by controlling the frequency converter. The IR5000 automatically adjusts the speed of the motor to achieve stable output pressure based on the actual amount of gas used to achieve energy savings. In addition, the use of VFD can also achieve soft start of the motor, reduce the frequent loading and unloading of the motor, reduce motor noise and other functions. First: Zhang Xudong, engineer, graduated from China University of Petroleum in 2005 with a 6's gas storage and transportation engineering. He is engaged in energy conservation and measurement management of long-distance natural gas pipelines. The operation of E-mail VFD can be roughly divided into two steps: 1) When the air compressor is unloaded, the variable frequency drive will run at a constant speed (.=27Hz) at a constant speed. 2 When the air compressor is loading and running, the variable frequency drive will automatically adjust the speed and stabilize the pressure. The IR5000 high-efficiency energy-saving control system is a towed type 2 variable frequency control system. The so-called tow type 2 can use the 丨R5000 to switch between the two air compressors' work/inverter mode. This ensures the energy saving space of the two air compressor systems and improves the reliability of the entire air compressor system. The IR5000 system is mainly composed of two parts: the ACS550 VFD is the main component of the system and is the product of ABB. The one-to-two inverter control cabinet is used to realize the switching of the working/frequency conversion modes of the two air compressors. Fault output of the inverter. The two parts are set in one cabinet, the middle partition is separated, and the VFD and control parts are independent installation spaces. 2 characteristics of the inverter 1) Inverter control compressor Compared with the traditionally controlled compressor, energy saving is the most practical. The compressor operating condition according to the gas demand is economical. 3 Improve the accuracy of pressure control. The variable frequency control system has precise pressure control capabilities. Match the air pressure output of the compressor to the amount of air required by the user's air system. The output air volume of the variable frequency control compressor changes with the change of the motor speed, which effectively improves the quality of the working condition. 3) Extend the service life of the compressor. The frequency converter starts the compressor from the low frequency, and its starting acceleration time can be adjusted, thereby reducing the impact of the Jit on the electrical components and mechanical components of the compressor during starting, enhancing the reliability of the system and prolonging the service life of the compressor. . In addition, the variable frequency control can reduce the current fluctuation when the unit starts. This fluctuating current will affect the power consumption of the power grid and other equipment. The frequency converter can effectively reduce the peak value of the starting current to a minimum. 3 frequency conversion transformation 1) due to the use of power frequency motor, the output does not change the load of the random group to change, the unit in the normal operation and hot standby conditions have frequent loading and unloading phenomenon, the unit's loading utilization is relatively low, resulting in The unit has frequent start and stop, with 20% and 40% energy saving potential. 3 The gas pressure fluctuation of the system is large (the maximum pressure difference reaches 1.9 Bar). Add 1 to 2 inverter control cabinets in the air compressor room, models are IR5000-22-ll, IR5000-45-ll, IR5000-132-丨丨, floor installation. Maintenance access channels are provided before and after. The inverter control cabinet consists of two parts: the inverter and the towed inverter control system. The main contents of the transformation include: 1) Adding electrical components (including fan power contactors, relays, etc.) in the air compressor internal control system, and retaining the original star/delta start when the air compressor is switched to the power frequency operation. 3 The pressure sensor is mounted on a pressure sampling point with a shut-off valve reserved for the gas storage tank. The pressure signal is made of two-core shielded wire (supplied by T-type). The hot-dip galvanized steel pipe is laid along the ground and cable trough to the inverter control cabinet. 3) Power distribution transformation. The power cable from the inverter control cabinet to the air compressor and the control power supply and the control cable to the air compressor are laid along the cable trough, and the local steel pipe is applied along the ground. 4) The main cable is laid along the line slot, and the new line slot is connected with the original line slot through the right angle tee, and the loading height is the same. Hot-dip galvanized grounding flat steel is installed in the wire trough to ensure good grounding of the equipment. 4 Comparison and analysis of benefits before and after the transformation In order to verify the power-saving effect of the frequency conversion transformation, the electricity meter was installed in the air compressor frequency conversion transformation, and the power frequency conversion test was carried out after a pressure station and two gas storage tanks: In the comparison of the 72h industrial frequency conversion power in the gas station and gas storage (see Table 1), within 72h, the electricity consumption using the frequency conversion operation is reduced by 32%, 18.4% and 18.3% respectively compared with the power consumption using the power frequency operation. According to the calculation of the running time of each station, the annual electricity consumption is reduced by 55X104kWh, the electricity cost is reduced by about 39.8X104 yuan, the energy saving is 67.6t standard coal, and the carbon dioxide emission is reduced by 168.5t. The investment of 6 frequency converters is more than 790,000 yuan, and the investment recovery period is 1.76. year. Table 1 Power frequency and frequency conversion operation power consumption comparison Continuous operation 72h power consumption / kWh power frequency variable frequency compressor station A gas storage B storage gas pool total 5 Conclusion Air compressor after the inverter is put into operation, the operation is good, the specific advantages are as follows : 1) The regulation is stable, the running current is obviously reduced, the adjustment range is wide, and the power saving performance is obvious, and the expected benefit is achieved. 3 It can realize one power frequency operation of the air compressor, the frequency conversion operation of the station, and the variable power frequency switching, or the two power frequency operation at the same time (not simultaneous frequency conversion operation); thus satisfying multiple air compressors Safe standby requirements in the case and maximum energy savings. 3) Constant pressure control, high-efficiency energy-saving control system with precise pressure control capability, according to the feedback of user system pressure, automatically control the speed of the air compressor main motor to provide stable pressure output; make the air compressor output pressure and demand pressure phase Match; the output air volume changes as the motor speed is adjusted. 4) The frequency control range of the air compressor with variable frequency control is 27~50Hz, which greatly reduces the energy consumption of the air compressor and reduces the production cost. 5) Due to the stable start, the air compressor noise is reduced, the working environment is improved, the air compressor is frequently started to decrease, the failure rate is reduced, and the social benefit, economic benefit and safety production benefit are very good. 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