Application of the hottest ABB frequency converter

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Application of ABB Inverter in oilfield water injection pump

oilfield water injection is an important and effective measure to maintain high and stable production in many oilfields in China. The method is to concentrate the oil scattered in the formation to the oil well and then extract it. As Daqing Oilfield is a fractured block oilfield, the water injection range of each block is small, and the water injection volume needs to be adjusted frequently with the change of production conditions. Most water injection stations have the problem that the rated flow does not match the actual flow. Due to the high pressure and large water volume of oilfield water injection, most of the water injection motors are high-power motors, and the motors have been running in a high energy consumption state for a long time. Using frequency conversion speed regulation device to regulate the motor used for oilfield water injection pump to realize the variable water volume control of water injection pump is a very effective energy-saving measure

the existing flow control mode

under normal circumstances, the high-pressure water injection in the oilfield adopts the gate valve control to adjust the flow and pressure. According to the process requirements, it is not allowed to operate with small displacement for a long time, otherwise the temperature rise in the pump will cause cavitation and burning of machine parts. In the past, the large reflux method was forced to reduce the temperature rise, resulting in a large amount of power consumption and a large amount of energy loss to the oil field

in the working condition of the original design system, two water injection pumps are used to inject water into the system. In the absence of frequency conversion and speed regulation transformation, the energy consumption loss of the water injection system under this working condition is mainly in the throttling of the control valve. Through analysis, only by combining the injection volume, reduce the water pressure and reduce the valves of each water injection well. 1 Affirmation of fatigue life: the purpose of energy saving and consumption reduction can be achieved by controlling the differential pressure under the given failure conditions

principle description of frequency conversion system

because the actual flow of water injection pump is smaller than the rated flow of pump, there is a great potential for power saving. The water injection control of the water injection pump in the system is that the feedback pressure value of the frequency converter through the transmitter is compared with the pressure value preset in the frequency converter in advance, and the PID regulator in the frequency converter automatically calculates and adjusts according to the difference to control the frequency conversion speed regulation operation of the frequency converter; At the same time, the operating parameters of the frequency converter are transmitted to the computer workstation through the internal computer interface and communication protocol; The operating pressure, motor speed, input/output voltage, input/output current and other parameters of the system can be detected and controlled on the computer at any time, so as to achieve the purpose of automatic energy-saving operation of the system

comparison between the frequency converter system and the original control system

1) the frequency conversion control mode is adopted, which is easy to operate without manually adjusting the water inlet valve, greatly reducing the labor intensity of workers and improving work efficiency

2) the starting noise is low. During the starting process, the motor accelerates slowly from low frequency, and reaches the set frequency after 20 seconds. Due to the small starting current, the impact on the electricity is reduced, the electrical equipment is protected, the service life of the motor is prolonged, the efficiency of the motor is improved, and the maintenance cost is reduced

3) the system adopts one driven two control mode, The pressure transformer is used to save the cost, and the current signal (4-20mA) is fed back by the transmitter to the central processing unit (CPU) of the frequency converter, which forms a closed-loop control system through PID control. The size of its output frequency is controlled by the action processor, so that the speed of the motor automatically increases or decreases; when the pressure exceeds the set target value, that is (> 5%) The first motor turns to power frequency operation, and the frequency converter starts the second motor to operate with frequency conversion to keep the water pressure constant. This not only reduces the reactive power of the motor, but also improves the working efficiency of the water pump and saves energy

4) the ordinary power frequency control mode (the original control mode) can not achieve such a purpose. Its start and stop need to be operated by people, and it also needs to adjust the water inlet valve switch to meet the requirements of working conditions, which is time-consuming and laborious, and it is prone to operational errors, resulting in unnecessary losses. The speed of the motor in the power frequency operation control mode is not adjustable, and the starting current is large. When the water supply pressure exceeds the required pressure value, it is necessary to manually adjust the size of the water inlet valve to meet the water supply pressure. At this time, the motor is still running at full load, and the excess power is consumed on the valve, which wastes a lot of energy

from the analysis of the above actual working conditions, the mode of frequency conversion and speed regulation is adopted to meet the needs of production, so that the water injection pump can operate at both high pressure and low pressure with large flow and small flow. The pressure or flow of water injection can be controlled by pressure closed loop or flow closed loop. When the working condition of the injection station changes, the frequency converter can make the water injection pump automatically adjust the water injection pressure or flow. At this time, the outlet valve of the pump is fully opened to reduce the differential pressure of the pump to zero. In this way, the electric energy is saved and the maintenance of the valve is reduced. It also improves the automation level of the system, reduces the noise of the system, improves the working environment, and reduces the labor intensity of workers. Frequency conversion speed regulation is adopted to obtain the actual water flow, Shubhayan Sarkar, a chemical analyst at BFS, said: "the backward integrated polymer manufacturer will better control the fluctuation of raw material prices, but save electric energy and improve the degree of automatic operation of the system; the frequency converter automatically adjusts the speed according to the demand, and smoothly and stably check whether the emergency stop key is in the stopped state, reducing the labor intensity of personnel; the operating parameters of the water pump are improved, and the system efficiency is greatly improved

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