Energy Saving Application of Centrifugal Pump in Sewage Treatment Plant

The operation of the pump is the result of the interaction between the pump and the discharge or pressure pipe. Centrifugal pumps are used to drive wastewater, providing a significant lifting force by not depending on external air pressure to lift the liquid.

The use of submersible pumps for sewage and drainage pumping applications has increased considerably in recent decades after their appearance on the market. The application of centrifugal pumps has the following aspects: Wastewater treatment and reuse, black water treatment, industrial wastewater, flood control, drain, and municipal wastewater disposal.

The energy-saving operation of centrifugal pumps requires the operating point of the pump to be in the most efficient area of the pump as much as possible. The intersection point of the characteristic curve of the pump and the characteristic curve of the pipeline is the working point of the pump. The working condition of the pump depends on three factors: the performance of the pump, the performance of the pipeline, and the water level difference in and out of the pool. If any of these factors change, the actual working point of the pump will change accordingly.

In the process of daily production and operation, the use of water pumps to save energy and reduce consumption mainly includes the following ways:

1. Pump hydraulic model and choice of pump manufacturer

Due to the difference in technical level and manufacturing capacity, the distribution of the type spectrum on the Q-H curve and the high-efficiency area distribution of the curve of the pumps of different manufacturers are basically inconsistent, and the operating effects of the manufactured pumps are also different. Therefore, you need to comprehensively select a pump that is most suitable for your plant system according to the working condition parameters you need, referring to the pump type spectrum of each manufacturer, the measured data of the corresponding pump, and the reliability of the actual operation of the pump of each manufacturer.

2. The high-efficiency area where the operating point of the pump matches the performance curve of the pump

Generally speaking, in the design scheme of the pump by the consultant, the parameters of the pump will always have some margin corresponding to the actual operating point. Therefore, we need to take the actual use as the benchmark, and through the corresponding adjustment methods, as far as possible. The working point of the pump is satisfied within the high-efficiency area of the pump.

3. The use of high-efficiency motors

According to statistics, the power consumed by the motor operation of the sewage treatment plant accounts for about 90% of the total power consumption. The main factors affecting the efficiency of the motor are the supply voltage, the size, design, and operating load of the motor. Generally, the efficiency of high-efficiency motors is about 8% higher than that of ordinary motors. Although the one-time investment in high-efficiency motors is 10% to 15% higher than that of ordinary motors, after the motor is put into operation, the payback period of this part of the investment is very short. The increased cost can be recovered in months or years.

4. The use of frequency conversion control

Frequency conversion technology is an energy-saving means that can adjust the existing flow to the actual demand flow and can maintain the working point of the pump in the high-efficiency area. In actual production, adjusting the frequency conversion according to the demand can greatly reduce power consumption, reflecting the significant energy-saving effect.

Permanent Magnet Motor Centrifugal Pump：

1. High efficiency and energy saving: Adopts IE5 ultra-high energy efficiency permanent magnet variable frequency motor and permanent magnets are used to provide excitation without excitation current and excitation loss, which provides the efficiency and power density of the motor. Compared with conventional asynchronous motors, the energy-saving rate is as high as 30% or more;
2. Superior performance: The permanent magnet motor adopts permanent magnet rotor rare earth magnetic steel, the entire 304 stainless steel shaft, high speed, stable and accurate synchronous speed, and better performance than conventional asynchronous speed;
3. Easy installation: Small and exquisite, 1/3 smaller than the conventional water pump, easy to install and save space;
4. Safe and reliable: It adopts the permanent magnet dedicated frequency conversion control system, multiple protections, and supports interconnection. Compared with conventional water pumps, it is safer and more intelligent, and permanent magnet motors never burn out.

Qingdao Enneng Motor Co., Ltd. (abbreviated as “ENNENG”) is a high-tech enterprise integrating R&D and manufacturing of permanent magnet motors. With more than dozens of patents, Enneng has ranked as “100 Innovative Enterprises” in Qingdao and have been selected as a member of the Qingdao Motor Association. Enneng would like to jointly work with users all over the world to focus on energy-saving solutions. Enneng’s main products include TYB Series Standard Type Permanent Magnet Motor, TYDP Series Direct Drive and Gearless Motor, and FTYP series of three-phase permanent magnet AC synchronous motors, etc. Whatever you need, our experienced engineers shall provide the effective solution as you required. Your demand is always what we pursue!