Abstract : Based on the actual working conditions of the circulating water renovation project at the Northwest Sichuan Water Purification Plant, this paper discusses the energy-saving principle of variable frequency speed control for circulating water pumps. The principle, composition, and function of the HARSVERT-A high-voltage variable frequency drive system are introduced. The paper focuses on the renovation scheme of the 4CV circulating water system at the Northwest Sichuan Water Purification Plant and the application of the high-voltage variable frequency drive to achieve a selective control system for temperature difference control and low-pressure clamping. The energy-saving effect of the circulating water system after the renovation is analyzed.
Keywords : High-voltage frequency converter, speed control technology, temperature difference control and pressure low-value clamping selective control system, energy saving
The cooling effect of the circulating water system at the Northwest Sichuan Purification Plant is achieved by controlling the opening of the outlet valve of the circulating water pump to regulate the flow rate. A significant amount of energy is wasted due to this outlet valve operation. The unstable cooling effect of the circulating water also affects the stable operation of the natural gas purification unit. Therefore, the Northwest Sichuan Purification Plant decided to upgrade its cooling circulating water system. AC motor variable frequency speed control technology is a widely used energy-saving technology. Variable frequency drive (VFD) technology can implement a PID control system, meeting the plant's control requirements. VFD technology enables soft start and soft stop of controlled equipment, ensuring smooth starting and limiting the starting current to within the rated current, thus avoiding impact on the power grid during startup. The reduced average pump speed extends the service life of pumps and valves. This measure not only reduces equipment failure rates but also significantly reduces power consumption, ensuring the safe, stable, and long-term operation of the cooling circulating water system.
1. Energy-saving principle of variable frequency speed regulation for circulating water pumps
1.1 Principle of AC Motor Variable Frequency Speed Control
For details, please click: Application of High-Voltage Frequency Converters in the Circulating Water Renovation Project of a Purification Plant in Northwest Sichuan
