Layi crude oil stabilizing device was put into operation in 1986, designed to process crude oil 10000t / d, Nissan light hydrocarbon 20t. The main equipment is screw compressor imported from the United States, model is 200H165. Main design parameters: treatment gas volume 1000m 3 / h, inlet pressure - 0 03 - 0 05MPa, compressor working speed is 10310r/min. Since 1994, with the decline of crude oil output in No.6 Oil Production Plant of Daqing Oilfield, the other supporting equipment is aging, the load rate of the equipment is also decreasing, the compressor can not Running at full load, sometimes running on the air, the efficiency of the device is reduced. Since 1996, due to the restructuring of enterprises into the market economy, the sales of light hydrocarbons in January and February have been sluggish, and the installation has been forced to limit production. During this period of time, the device load rate is only 60% and 70%. It is maintained by the replenishment and recirculation. The rated power of the main motor of the compressor is 186 kW, and the power of about 30% is doing no work. To this end, the device needs to be energy-efficiently modified. 1. The principle of frequency conversion energy-saving transformation According to the formula of the speed of the asynchronous motor, there are three methods for adjusting the speed of the asynchronous motor: changing the number of pole pairs of the motor. This method can only change the number of poles of the asynchronous motor by a multiple jump, so this speed regulation is a stepwise speed regulation, which is neither economical nor practical in production; change the slip rate. The circuit connection of this method is also complicated, the modification is difficult, and it is not easy to operate in production; the frequency of the power supply is changed. This method is proportional to the speed of the rotating magnetic field and the frequency of the input current. When the current frequency is changed, the rotational speed of the rotating magnetic field can be changed, and thus the rotational speed of the rotor is also changed, which can achieve the purpose of speed regulation. Using this method to adjust the speed, the speed range is large, and smooth shifting can be realized. It is a reasonable speed control method for asynchronous motors. The inverter can realize this adjustment. The device first converts the 50Hz AC power into a DC power with a controllable rectifier, and then converts it into an AC power source with adjustable frequency to control the motor speed. In order to keep the voltage to frequency ratio constant, to maintain the main magnetic flux of the motor, the amplitude of the voltage can be adjusted by the amplitude and width of the pulse while the frequency is being converted. The voltage and frequency are simultaneously reduced or increased to achieve the purpose of speed regulation and power saving. 2. Frequency conversion transformation plan 2.1 Main equipment selection (1) Inverter. According to the compressor motor power and rated current, the inverter of model VS 616H3 is selected. The inverter is made in Japan. Its main parameters are: motor power <200kW; voltage class is 400V; frequency modulation range is 0 50Hz. (2) Pressure transmitter. The explosion-proof type is selected according to the process conditions, the pressure range is - 0 1 + 0 1MPa, and the output signal is 4 20mA. (3) Regulator. The regulator is the core part of the control system, choose DTL? 3110 regulator, input and output signals are 4 20mA, working power supply 24V DC. (4) Other materials. Air switches, AC contactors, control cables, power cables, etc. are selected according to specifications. 2.2 renovation plan The high-performance, low-noise general-purpose inverter made in Japan is used to install the inverter on the three incoming lines of the original motor. The input end of the inverter is connected to the AC contactor and the air switch is finally connected to the 380V input line. The output is connected to the motor via a cable. A pressure transmitter is connected to the compressor inlet line. The working range is - 0 1 + 0 1MPa, which is used to measure the pressure signal. The pressure transmitter can convert the measured pressure value into a 4 20mA DC signal output. The transmitter operates from 24V DC and is explosion proof. The regulator connected to the control panel of the control room through the control cable is DTL 3110 type, the output signal is 4 20mA, and the control cable is connected to the inverter control signal input. The control of the frequency converter is realized by the regulator. The regulator can be divided into automatic control and manual control. According to the electrical signal input by the pressure transmitter, the adjustment range of the regulator is set to 0 100%, and the regulator output signal is connected. The input end of the inverter controls the input signal value of the inverter by setting the set value of the regulator, and then outputs the three-phase AC power of the corresponding frequency through the operation of the inverter, thereby controlling the number of revolutions of the compressor motor. The purpose of adjusting the compressor load is achieved. For example: When it is determined that the normal operating pressure of the compressor inlet is at - 0 04MPa, the corresponding value of the regulator is set, and the regulator is set to the automatic state, the inverter can output the corresponding frequency according to the fixed value of the regulator. Three-phase alternating current, the compressor operates under a certain load. When the compressor processing gas volume fluctuates, the inlet pressure deviates from the operating value and is exceeded. At 0 01MPa, the set value range of the regulator is also exceeded at this time. The regulator automatically adjusts the compressor speed by controlling the electric signal input to the inverter, so that the compressor reduces or increases the processing capacity, and the compressor is always in the optimal operating state. The compressor motor no longer performs the useless work caused by the insufficient load and the recirculation of the gas, thereby saving a large amount of electric energy. Since the maximum inverter output of the inverter is 50 Hz, the compressor will not overspeed even when the air volume is too high. For load reduction (such as limited production, crude oil planning, etc.), the inverter can also be driven to the manual position, which is manually adjusted by the operator. 3. Transformation effect and economic evaluation The project was completed in June 1994 and has been operating normally since it was put into operation. The production equipment guarantees the smooth operation of the production equipment when the incoming materials are unstable or the materials are low and the light hydrocarbons are sold in the off-season. At the same time, the power saving benefits are remarkable. In particular, in the first half of 1997, the international oil price was low, domestic oil sales were not smooth, and when the oil field was shut down, the crude oil treatment capacity of the device was greatly reduced. The adjustment of the frequency converter ensured the normal operation of the device. Since there is no separate electricity meter for the main motor of the compressor, the statistics of the equipment operation from June 1994 to June 1999 are comprehensive. The average number of days with less than 70% load per year is 60d, and the number of days with less than 50% load is 20d. Operating parameters after frequency conversion adjustment. Compressor frequency conversion adjustment operating parameter statistics frequency converter adjustment (%)30 50 70 100 input frequency (Hz) 15 25 35 50 motor current I (A) 120 195 230 280 motor input voltage U (V) 110 190 280 380 compressor inlet Pressure (MPa) + 0 06 + 0 005 - 0 025 - 0 045 Compressor outlet pressure (MPa) 0 100 0 150 0 15 0 155 Compressor outlet temperature ( % ) 55 78 90 115 Furnace outlet temperature ( % ) 58 61 65 68 Motor power theoretical value (kW) 11 37 1 64 4 106 4 Note: (1) The data in the table is the average value of 5 groups of data admitted after 10 hours of frequency stabilization of the frequency converter (2) Due to the large gas collecting pipe network, the outlet pressure is relatively stable (3) Motor parameters: rated power is 186kW, the number of revolutions is 2975r/min, the frequency is 50Hz, the rated current is 338A, the annual power saving is 93744kWh, the accumulated power saving Is 93744 5= 468720kWh. 4. Conclusion (1) Using the frequency conversion technology to change the motor speed, adjust the compressor operating conditions, reduce the useless power loss of the main motor, and have great power saving benefits. At the same time, it ensures that the unit runs smoothly. (2) In industrial production, some large-power equipment can explore the use of frequency conversion technology to adjust equipment working conditions and solve the problem of excessive energy consumption under the condition of insufficient load or unstable working conditions. (3) The frequency conversion technology can realize stepless speed change, large speed regulation range, smooth speed regulation and easy operation. Applied for river water/lake water/sea water/well water Applied for river water,lake water,well water GuanYu Environmental Protection Equipment Corp., Ltd. , http://www.hbuvsterilizer.com
The use of frequency conversion technology to change the motor speed, adjust the operating conditions of the compressor, reduce the useless power loss of the main motor, has a great power saving effect. At the same time, it ensures that the unit runs smoothly. In industrial production, some large-power equipment can explore the use of frequency conversion technology to adjust equipment working conditions and solve the problem of excessive energy consumption under the condition of insufficient load or unstable working conditions. The frequency conversion technology can realize stepless speed change, large speed regulation range, smooth speed regulation and easy operation.