Research and Application of Pump Frequency Control Technology

The Daqing Petroleum Administration Water Supply Company consumes a significant portion of its total operational cost in electricity, with approximately 30% of the overall water supply cost attributed to energy usage. Within this, transmission and distribution account for about 70% of the electricity bill. Optimizing daily pump operations to maintain an efficient balance between water and electricity usage is crucial for energy conservation. To address this challenge, we have actively explored various strategies, conducted thorough research, and implemented effective measures. The Longhu Bubble Water Plant, located on the northern bank of the Dragon and Tiger, has a design capacity of 500,000 cubic meters per day. It originally featured two pumps: one with a 1400KW/10KV motor and a 900HR pump (H62m, Q6360m³/h), and another with a 900KW/10KV motor and a 700HR pump (H62m, Q3900m³/h). However, due to declining external water demand from the oilfield, the actual daily water supply has dropped to 250,000–300,000 cubic meters. The system flow rate is now only around 104,000–125,000 m³/h, significantly below the original design. This underutilization causes the pumps to operate at high pressure, leading to inefficiency, increased power consumption, and mechanical stress. Adjusting the outlet gate to control pressure results in unnecessary energy loss and higher maintenance costs. Over the past two years, the pumps have required over 10 major repairs, costing more than 100 million yuan. Given the critical role of the plant in the oilfield, a technical upgrade was urgently needed. To address these issues, we evaluated frequency conversion as a solution. By adjusting the motor speed using variable frequency drives (VFDs), the pump's performance curve can be matched with the system's requirements, reducing pressure differences and energy waste. The relationship between flow, head, and power follows the affinity laws: - Q₁/Q₂ = n₁/n₂ - H₁/H₂ = (n₁/n₂)² - N₁/N₂ = (n₁/n₂)³ For example, if the 3# pump’s speed is reduced from 748 rpm to 500 rpm, the flow would decrease by 1.496 times, the head by 2.23 times, and the power by 3.36 times. This adjustment aligns the pump's operation with current demands, minimizing energy losses and extending equipment life. Based on calculations, reducing the pressure from 5.8 kg to 2.5 kg could theoretically cut energy consumption by 57%. At an electricity cost of 0.41 yuan/kWh and a motor efficiency of 95%, the annual savings could reach 272.5 million yuan. After implementing VFDs, the 6# pump was tested, showing stable operation and improved efficiency. Energy meter readings confirmed that the unit power consumption dropped from 0.24 kWh/m³ to 0.14 kWh/m³, achieving significant savings. Post-transformation, the water supply process improved. The PLC-based control system enhanced automation, reduced manual operations, and improved safety through cooling water protection. Pressure regulation became more accurate, and the system’s flexibility and reliability were greatly improved. Additionally, the soft-start function of the VFD reduced mechanical stress, extended equipment life, and lowered maintenance costs. In conclusion, the frequency conversion project at the Longhu Bubble Water Plant proved highly successful, delivering substantial economic and environmental benefits. It not only reduced energy consumption but also improved system flexibility, safety, and working conditions. High-voltage VFD technology is a promising solution for the water supply industry, offering practical value and long-term benefits. This technology will play a key role in future energy-saving initiatives in the sector.

Combination Rope

Playground Combination Rope,Fiber Core And Steel,Wire Rope,Pp Danline Rope

Yangzhou Jieerte Steel Cable Co., Ltd , https://www.jieertesteelcable.com