How to carry out energy-saving upgrades for circulating water pumps

Thread Content

Circulation water pumps are widely used in industries such as petroleum, chemicals, metallurgy, pharmaceuticals, and power generation, and their power consumption cannot be ignored. Carrying out energy-saving upgrades to the circulating water pump system holds great economic value for enterprises in reducing consumption and increasing efficiency. Our company has been dedicated to energy-saving services for water pump systems for a long time; we have upgraded dozens of circulation water pumps and possess extensive practical experience in this field, which we would like to share with you here. We can summarize the principle of energy savings in water pump systems in one sentence: \"Operate high-efficiency pumps at their optimal operating points to reduce pipeline losses, especially throttling losses.\" This sentence contains three key terms: high-efficiency water pump (pump efficiency), high-efficiency point, and pipeline losses, which are also the three key aspects for energy savings in water pump systems. (1) High-efficiency water pump (pump efficiency): To save energy, the pump efficiency must be high. The efficiency of a water pump depends first on its design quality, and secondly on the precision and quality of its manufacturing ； (2) Efficiency points: For the same water pump, its efficiency varies at different flow rates; it is generally highest near the rated operating conditions. If the operating conditions deviate significantly from the rated ones, even if the pump’s rated efficiency is high, its actual operating efficiency will be low. Going a step further, for high efficiency it is also necessary to consider the motor’s load rate and its efficient operating range; in other words, the overall efficiency of the entire water pump system should be at its optimal level. (3) Pipeline losses: Pipeline losses should be minimized, and throttling losses should be eliminated as much as possible. We achieve energy savings by focusing closely on three key aspects: pump efficiency, the optimal operating point, and pipeline losses. We conduct scientific analysis and diagnosis of the actual operating conditions of the pumps, and by using advanced theories and scientific methods, we identify the problems existing in the pump system. Targeted and effective measures are then taken to fully exploit all potential opportunities, thereby increasing the rated efficiency of the pumps, ensuring that their actual operating parameters are at the optimal level, and minimizing pipeline losses. It is through the integrated application of these three aspects that we attain our energy-saving goals – this is our principle for energy conservation. Our specific energy-saving measures are as follows: 1. Conduct on-site investigations to accurately diagnose the problems existing in the system, and then determine the design parameters in a targeted and precise manner. 2. Improve the rated efficiency at the design operating point through advanced design skills and energy-saving concepts. We make extensive use of advanced design theories such as three-dimensional flow theory, combine them with CFD flow field analysis and dynamic simulation, target specific operating ranges, draw on excellent hydraulic models, and employ advanced CAD design software. Most importantly, we have experienced senior designers who bring decades of design experience and insights to bear, enabling the pumps and impellers designed to achieve efficiencies close to the limits under specific operating conditions. Old pumps or impellers are replaced with high-efficiency pumps or impellers (three-dimensional flow impellers). 3. Eliminate inefficiencies caused by operating condition deviations. Ordinary water pumps are series-produced standard products, with a limited set of specifications spaced at appropriate intervals to meet a wide variety of operating conditions; it is not possible to design and manufacture them based on the specific requirements of a particular factory. The limitations of the pump product range, coupled with the great diversity in actual production conditions, inevitably lead to a mismatch between the performance parameters of pumps and the requirements of actual manufacturing processes as well as the actual resistance in the pipelines. This results in pumps operating outside their efficient range ； Changes in the pump load due to various reasons can also cause the pump to deviate from its high-efficiency range ； All of this leads to inefficiency and results in energy waste. Based on the specific circumstances, we take various measures to eliminate operating condition deviations and bring the water pump back to operate in its high-efficiency range. 4. Customized and specially designed to eliminate unnecessary power consumption. When carrying out engineering design, design institutes generally do not perform precise calculations regarding the flow rate requirements of each water pump or the pipeline resistance; instead, they rely on analogical estimates. This approach is relatively conservative in order to ensure safety and reliability, resulting in unnecessary power consumption. Based on the actual operating conditions of the customers, we determine the specific parameters appropriately and design pumps tailored to those conditions, ensuring that the pumping capacity matches the actual load perfectly – neither too high nor too low – thereby improving operational efficiency and achieving energy savings. 5. Optimized combination of multiple pumps for overall system optimization: Through a matched and optimized design of the entire system, including motors, water pumps, transmission devices, speed control devices, piping networks, and working devices, rational scheduling is achieved to ensure economical operation, improve the overall efficiency of the system, and achieve energy savings. Specific measures include: properly configuring water pumps, scheduling energy-saving operations in accordance with changes in production load, in order to achieve energy savings ； Improve the operating efficiency of motors, etc ； Reasonable diversion and return flow ； Reasonable series and parallel operation of water pumps, etc. 6. Adopt speed regulation and energy-saving technologies (variable frequency speed control, permanent magnet speed regulator control, coupling speed control, etc.). Variable frequency speed control is one of the most widely used energy-saving technologies in water pump systems today; it is widely recognized and accepted, and has made a significant contribution to energy savings in such systems. However, it should be recognized that some operating conditions are not applicable, and the inverter itself consumes 3–5% of electricity. 7. Precision casting, along with careful polishing, improves product quality and accuracy at the manufacturing stage, thereby enhancing efficiency. 8. The latest research findings on improving the efficiency of water pumps, successful experiences from various minor improvements, as well as various \"ad hoc\" solutions and \"secret recipes\" were widely collected. These were then analyzed and evaluated, with some of them selected for further testing at significant cost. Through summarization and application, many unique insights were gained, thereby enhancing the technical level of energy-saving services. To achieve good energy-saving results, it is necessary to adopt different energy-saving technologies tailored to specific situations, and combine several effective measures for energy savings. I would like to share with you a few recent cases from our company, so that you can get a general idea of the energy-saving effects achieved through pump upgrades. 1. After replacing the impellers of a company’s #qsn300-m9 double-suction pump with our specially designed high-efficiency impellers, the motor current of the water pump decreased from 280A to 230A at the same flow rate, resulting in an energy-saving rate of 17.8%. 2. After installing the specially designed high-efficiency impellers in a company’s #qsn250-m6 double-suction pump, the flow rate increased slightly compared to before, yet the motor current dropped from 223A to 153.8A, achieving an energy-saving rate of 30% ； 3. A chemical company carried out an expansion upgrade on its #qsn250-m9 double-suction pump; with the same valves and piping system, the flow rate increased from 490 cubic meters per hour to 560 cubic meters per hour, and the efficiency improved significantly. 4. The circulating water pump 24SH-9B of a certain chemical company has a flow rate of 2,800 cubic meters per hour, a head of 56 meters, and an electric motor with a power rating of 560 KW. It originally consumed 520 kWh of electricity per hour; after replacing it with our high-efficiency impeller, the electricity consumption dropped to 470 kWh per hour, resulting in a savings of 50 kWh. 5. A company replaced its OS350-510B double-suction pump with our energy-saving pumps, achieving an energy savings rate of 15%. 6. Another company replaced its 10sh-6A water pump with our energy-saving pumps; as a result, the current required for the same flow rate decreased from 145A to 105A, resulting in an energy savings rate of 27%. Steps and characteristics of energy-saving renovation of circulating water pumps using high-efficiency three-dimensional flow impellers: Based on the actual operating conditions of the user’s water pumps, and with the aim of fully meeting those operational requirements, this approach relies on the theory of full three-dimensional jet-trail flow. Design software such as PCAD and CFD is utilized, along with the extensive experience accumulated by senior engineers, to carry out comprehensive optimization. High-efficiency three-dimensional flow impellers that can be interchanged are then redesigned and manufactured; these impellers can be installed within the original pump casing without any need to modify the existing equipment foundation, motors, pipelines, etc. The installation process is simple and fast, the project implementation is safe and convenient, and the energy-saving effects are significant. It can thus be considered the preferred solution for energy-saving renovations of water pumps. Original material; citation by peers is prohibited