Abstract: This article introduces the application of frequency converters in the petroleum and chemical industry. Energy-saving effects are illustrated through examples, and issues that should be noted when using frequency converters are briefly analyzed.
Keywords : frequency converter; energy saving; petrochemical industry
1 Introduction
The petrochemical industry is a fundamental sector of the national economy and also a major energy consumer, with its main production processes relying on various pumps and air compressors. Currently, most of these oil pumps, water pumps, and air compressors operate at constant speed driven by electric motors. If the majority of non-speed-regulating motors were converted to speed-regulating operation, allowing their power consumption to vary with the load, significant energy savings could be achieved, resulting in substantial energy efficiency. The development of modern power electronics and AC speed control technology has led to a significant leap forward in AC motor variable frequency speed control in terms of frequency range, dynamic response, accuracy requirements, and performance. According to incomplete statistics, squirrel-cage asynchronous motors account for 80% of the total motor capacity in large and medium-sized petrochemical enterprises, thus providing ample room for the application of AC speed control technology in the petrochemical industry.
2. Application of frequency converters in the petroleum industry
2.1 Application in beam pumping units
Beam pumping units are convenient, reliable, and economical, making them a primary piece of equipment in oil production. To reduce load fluctuations during the upstroke and downstroke, they are typically equipped with counterweights. The load on the pumping unit motor is a periodic, pulsating load, superimposed with transient impacts. The motor's load curve has two peaks, representing the "dead points" during the upstroke and downstroke. When restarting after a free stop, the pumping unit always starts from these dead points; therefore, the motor requires a high starting torque. To ensure sufficient starting torque, the motor operates at a very low load rate during normal operation, typically around 20%, with a maximum load rate of no more than 30%. Low load rate operation results in a low power factor, low efficiency, and significant energy waste.
For details, please click: Application of Variable Frequency Speed Control Technology in the Petroleum and Chemical Industry
