Selection of vacuum pumps and hydraulic ejectors
Thread Content
For vacuum systems with the same performance parameters (evacuation rate of 100 cubic feet/h, absolute pressure of 200 mmHg), between a vacuum pump and a hydraulic ejector (note: the water for the hydraulic ejector is supplied by a pump; the inlet pressure is considered to be at atmospheric pressure, and the water is reused), which design requires a smaller power output from the motor? Since I’m not in the design field, I’m not sure if all the requirements have been met. If necessary, please point them out so I can make the necessary adjustments. Last edited by sister on 2009-3-8 23:55]
The power of the hydraulic ejector is low; there’s no calculation based on experience – this is for reference only
In line with the principles of energy conservation and reduced consumption, vacuum pumps are undoubtedly economical, water-saving, stable in operation, and have high power output
The pump’s efficiency is already low, and the hydraulic losses associated with spraying are even greater. The efficiency of vacuum pumps is significantly higher.
I also think that vacuum pumps are more efficient; using a jet pump means that energy has to be converted twice, and the more conversions there are, the more energy is wasted and the poorer the stability becomes. It’s better to choose a vacuum pump directly.
It depends on how economic the solution is. If the steam used in the steam jet pump can be recycled, then the steam jet pump is the best choice, as it offers good efficiency in all aspects. However, if the steam cannot be recycled and even needs to be condensed, then a water ring pump would be more suitable, as it results in lower costs.
A vacuum level of 200 mmHg is not a high requirement. In terms of energy consumption, water ring vacuum pumps certainly have lower energy usage. Moreover, it is possible to purchase high-quality products from domestic brands, which results in lower investment costs; such pumps are definitely better than water jet pumps
Regarding vacuum systems, apart from the two basic types of vacuum pumps and hydraulic ejectors, has anyone considered other options? For example, by using the principle of turbocharging? This method might be better!
Calculated based on the dechlorination of 50,000 tons of chlor-alkali. A water injector requires a motor of about 45 KW. A 10KW vacuum pump is sufficient.
Regarding the selection between vacuum pumps and hydraulic ejectors, I believe a hydraulic ejector is what we commonly refer to as a water jet pump. In 2004, our factory carried out a technical renovation project to upgrade two 12MW double-suction condensing units, and we encountered some challenges in selecting equipment for the air extraction system. Our factory previously used steam ejectors; for the new units aimed at energy savings, we plan to use water ejectors. As per our requirements, the turbine factory supplied us with inefficient water jet pumps; the motor for these pumps had a power rating of 45 KW. We raised objections to this, and after conducting calculations and consulting with the manufacturer of the auxiliary equipment, we ultimately opted for the TDN-12 type of efficient water jet pump. This reduced the power requirement of the pumps from 45 KW to 22 KW. Based on 300 days of operation per year, this approach results in annual energy savings of 130,000 kWh.