Summary Guangzhou Development Zone sewage treatment plant for pumping station design and actual use of a larger gap caused by the pumping station over the water consumption is too high, take the pump set to adjust the pump impeller cutting pump station PLC and frequency control and other technologies Change measures, greatly reducing the power consumption of the pumping station, and to achieve uniform water delivery to the plant.
Key words sewage pump station pump technology modification impeller cutting frequency conversion control
0 profile
Guangzhou Development Zone sewage treatment plant mainly collects and disposes of the sewage in the west zone of Guangzhou Development Zone. Due to the flat terrain and unnatural terrain, 10 pumping stations are planned in the 9.6 km2 service area to facilitate the collection of sewage (see Figure 1). At present, in addition to 1 #, 2 # pump station is not building, 8 # pump station is not under construction, the remaining pumping stations have been put into use. Can be seen from Figure 1, due to the sewage into the plant on many occasions to enhance some of the sewage up to 4 times, making the sewage transport costs are higher. Irrational pumping station design, increasing the power consumption, so that pump sewage pumping power consumption per m3 up to 0.132 kW · h.
Figure 1 into the factory pipe network and sewage pumping station schematic
The plant to deal with the water according to the first phase of 30,000 m3 / d, two 60,000 m3 / d, the third phase of 90,000 m3 / d for the overall planning. At present, the design and treatment scale of WWTPs is 30,000 m3 / d and the actual influent water volume is only 17,000-25,000 m3 / d. However, the pump stations (# 3, # 5 and # 7) that are directly imported into the plant are designed and installed Pumps are 90,000 m3 / d configuration. As can be seen from Table 1, in the first phase of the sewage treatment 30,000 m3, the original design configuration of the "3 with 1 prepared" or "2 with 1 prepared" pump, the actual "1 with 3 prepared" or "1 with 2 Standby ", and" 1 use "of the pump is often in the open when the stop state, some pumping stations even open only 10 minutes per hour. This will not only damage the equipment, but also easy to produce a large amount of water for the factory process, water impact load, increase pumping station and plant sewage treatment power consumption.
In addition, it can be seen from Fig. 1 that the pipe network of No.3, No.5 and No.7 pumping stations directly entering the plant is fully connected through the water distribution wells in the plant area, as the pumping station is not additionally set up in the plant area, forming a pipe network system up to 4km . This will occur when one pumping station pumping while the remaining two pumping stations are not pumping, pumping station water will enter the other two pumping station pipe network, thereby reducing the pump's actual pumping efficiency, an increase of repeated pumping cost.
1 Adjust the pump set
According to the service area water plan (for a long period of time, the amount of sewage will not exceed the design of water), and the water pumping stations in different circumstances, the existing pump in the plant for each pump into the plant pumping station Adjustment. For example, if the daily water delivery of pump station # 5 is between 10,000 and 15,000 m3, the four pumps with a power of 75 kW in the original design will be changed to one with a capacity of 55 kW and two 75 kW pumps. 3 # The daily pumping capacity of the pump station is 3000 ~ 5000 m3, and the pump configuration is changed from 4 pumps of 75 kW to 1 kW of 22 kW and 1 kW of 55 kW. The daily water delivery of pump station # 7 is 4000 ~ 5000 m3, the pump configuration from the original 3 sets of 75 kW pump to a 22 kW, a 55 kW, by re-adjusting the configuration of the main pumping station pump, so that the pumping station per m3 sewage transmission of electricity consumption Decline of about 8%.
2 to improve the pump impeller to improve pumping efficiency
The original 75kW and 55kW pumps have a head lift of 31 m and 41 m, respectively, which is much higher than the actual hoisting height of the pump station to the factory (about 15 m), so the pump is wasted head-wise. In other words, the original pump design selection, and the actual difference between the larger. Of course, changing the pump is the easiest way, but changing the pump requires a lot of capital investment. It is also a good idea to redesign and replace the impeller using the existing motor pump body. However, because the original pump was manufactured in Japan, Pump variety, a small number, there is no contact with the manufacturers willing to undertake this task (this work is still continuing to do). To this end, took the impeller cutting adjustment of the way to transform the pump. The so-called impeller cutting adjustment that is through the outer diameter of the small pump impeller, changing the pump performance curve to make it closer to the actual required head and flow range, thereby enhancing the pump pumping efficiency.
According to the law of the proportion of impeller cutting and the actual situation in the region, and combined with the required flow, lift and power consumption, through a detailed theoretical calculation, first select the appropriate turning ratio, and then the pump impeller cutting test (see Table 2). It can be seen from Table 2 that after the impeller is cut by 13%, the pump pumping efficiency is improved by 30% ~ 40%.
3 pump station automation transformation
The original pump station, using a simple relay - contactor control, entirely by manual control, coupled with the pump too conservative, a single pump capacity selected larger, and the lift is too high, can not be achieved reasonable scheduling, The formation of water quality impact on the plant load, power consumption larger. To this end, after the transformation of the mechanical equipment in the pumping station, that is, automated transformation, configuration of a PLC and a frequency converter in each pump station, through the water level meter to detect pump room water level, adjust the frequency of the pump and the number of open , Keep the pump running in the best efficiency range, reduce energy consumption and avoid the damage caused by frequent start-up to the equipment, realize the uniform water delivery to the plant area, ensure the water treatment process in the plant area to run economically and steadily, and also avoid the sewage Repeated flow in the pipe network. After the completion of this step, the water supply and power consumption will be reduced by 29.5% on the basis of the previous reconstruction.
Figure 2 shows the actual pumping station of the plant from 2000 to 2001. As can be seen from Fig. 2, from March 2000 to June 2000, the average pumping power consumption of the pumping station decreased from 0.132 kW · h / m3 before the renovation to 0.105 kW through rational deployment of the pump and impeller modification of the pump h / m3; from January 2001 to April, after the completion of the automation, the power consumption of water transmission will be further reduced to about 0.075 kW · h / m3.
Figure 2 2000-2001 pumping station actual power consumption situation
4 Conclusion
Guangzhou Development Zone sewage treatment plant design for the pump too far ahead of the design volume is too large and the actual use of the larger gap caused by excessive water pumping station situation, taken a variety of transformation measures. After the completion of all the transformation, the actual pumping power consumption of the entire pump station was reduced by 43.9% compared with that before the transformation.
â—‡ Author Correspondence Department: 510730 Guangzhou Development Zone sewage treatment plant
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