Efficient energy saving vacuum device
Under the background of countries vigorously promote energy conservation and emissions reduction, combined with the power plant in recent years the emergence of gas-cooled roots pump, development, technology matures and our roots water ring vacuum unit in petrochemical industry for more than a decade to verify its reliability, so it will be high efficiency and reliable operation of roots water ring vacuum unit in power plant, and has obtained the very good application effect.
As the water of the water ring vacuum pump is used as the working fluid, it is more suitable for the high water content of the condenser. Moreover, as a positive displacement pump, the water ring vacuum pump can change its pumping capacity synchronously with the back pressure of the condenser. When the air leakage of the condenser increases, the output of the water ring vacuum pump increases rapidly, which can well restrain the further increase of the condenser pressure and ensure the optimal output of the generator set. Therefore, most of the condensers vacuum systems in coal-fired power plants use water ring vacuum pumps. At present, the vacuum pump used in the vacuum system of condensers in domestic power plants is mainly water ring vacuum pump. Water ring vacuum pump is characterized by a higher vacuum degree and a smaller amount of air extraction. Meanwhile, its air extraction performance is also greatly affected by water temperature. In addition, in the high vacuum stage, water ring vacuum pump is prone to cavitation, resulting in increased vibration, increased noise, impeller easy to damage.
The vacuum extraction process of the condenser in power plant can be divided into two stages: the start-up vacuum stage and the maintenance vacuum stage. In the starting vacuum stage, since the condenser is pre-pumped from atmospheric pressure to the vacuum in which the unit can be put into operation, the unit in this stage has no power generation, so the shorter the time is, the better, and the large amount of air is required for the vacuum system. In general, two or more water ring vacuum pumps need to be used in parallel. In the stage of vacuum maintenance, since the vacuum pump is mainly the air leaked by the condenser, the vacuum pump needs a small amount of air, so it is often necessary to run a water ring vacuum pump to maintain the vacuum.
As the vacuum maintenance time of the condenser in the power plant accounts for more than 80%, if energy saving transformation is to be carried out, the main idea is to improve the vacuum of the water ring vacuum pump in the high vacuum, thereby improving the vacuum of the condenser, so as to improve the power generation efficiency and reduce energy consumption. The domestic power plant generally adopts the methods of series atmospheric ejector, series steam jet pump, reducing the working water temperature of water ring vacuum pump and so on to carry out the work, and has also obtained certain achievements. However, the energy consumption of the water ring vacuum pump was not reduced, although the vacuum degree of the condenser was improved.
With the development of vacuum technology, a new vacuum pump, air-cooled roots pump, is gradually developed and mature. Air-cooled roots pump is a kind of dry pump, which has the characteristics of higher vacuum degree and larger air volume, and its working efficiency is very high, generally more than 80%. The efficiency of water ring vacuum pump in high vacuum is only about 15%, even if the series of atmospheric ejectors, the efficiency can only be raised to about 20%. If the air-cooled roots pump could replace the water-ring vacuum pump, the efficiency could be increased by about 70%.
The inlet pressure of water ring vacuum pump is maintained at about 130mbar, avoiding cavitation area and running more smoothly; At the inlet of the liquid ring pump, there is an automatic vacuum breaker valve and a reverse check valve. The roots water ring vacuum unit not only increases the vacuum degree of the condenser and thereby improves the power generation efficiency, but also has more than 75% electricity saving effect and more than 50% water saving ability compared with the previous operating units.
The air cooling roots vacuum pump is adopted. The material of roots vacuum pump is universal material. The over-flow parts are plated with nickel and phosphorus.
The improved 2BE1 water ring vacuum pump is equipped with more stable performance and more reliable operation.
Improved 2 be1 series liquid ring vacuum pump is my company in the introduction of Germany's Siemens 2 be1 series vacuum pump on the basis of relying on the rich experience in the production of liquid ring vacuum pump for over 30 years and strong development capacity, using advanced CFD aviation design software and 3 d CAD software, the structure of secondary development, and constantly to improve and has the world advanced technology level of vacuum pump.
The vacuum pump in the complete set of 2BW5 pump plant in hubei province is made of whole-process controlled casting impeller, and the vacuum pump provided by shenlong pump plant in hubei province is not only reliable in operation, but also reduces the back pressure of the condenser and greatly improves the operation efficiency of the thermal power unit of the power station.
The exhaust opening of flexible valve plate is adjusted automatically within the full performance range
The vacuum pump equipped with roots water ring vacuum unit is a plane structure form with unique flexible exhaust port (see the following picture), which can automatically adjust the exhaust Angle according to the different vacuum in the pumping system and the principle of pressure balance. Compared with the double-stage vacuum pump with rigid exhaust port and fixed compression ratio, it has the following advantages:
The compression ratio range from 1:1 to 1:33 can be operated efficiently (please refer to relevant vacuum pump performance curve).
Before starting the steam turbine, compared with the two-stage pump, the plane pump can draw the predetermined vacuum in the shortest time.
During the vacuum maintenance of the condenser, the vacuum pump, which automatically adjusts the compression ratio, is able to cope with the operation of the unit in summer, winter or peak condition. Make the generating set get the best output;
When excessive air leakage occurs accidentally into the condenser, the vacuum pump with flexible exhaust port is better than the vacuum pump with rigid exhaust port in controlling the back pressure rise of the condenser.
The vacuum pump is equipped with a cavitation prevention valve. Through the pressure difference between the two sides of the valve ball in the cavitation prevention valve, a proper amount of gas is automatically filled in the bubble rupture zone to fill the "space" generated by the bubble burst. Prevent cavitation damage to part surface caused by bubble rupture.
It is known to all that high energy consumption and low efficiency still exist in the liquid ring vacuum pump. The efficiency of the existing small size liquid ring pump is generally 30% to 45%, and the large size pump can only reach 50% or slightly higher. The main reason for the low efficiency of the liquid ring vacuum pump is the large hydraulic loss caused by the gas-liquid two-phase flow in the pump. Whether quantitative results or qualitative analysis, whether numerical calculation or flow field display, the specific distribution of gas-liquid two-phase flow field in a liquid ring vacuum pump has not been given at home and abroad. On the other hand, the current liquid ring pump flow theory and analysis method cannot accurately and effectively describe the unsteady gas-liquid two-phase flow in the pump, so the conventional design method based on the current liquid ring pump flow theory is naturally difficult to design efficient liquid ring vacuum pump products.
The matching power of the vacuum pump bidding is 22KW and the matching power of the rotz pump is 18.5kw.
Our company is specialized in the production of water ring vacuum pumps in power plants. The important parts of roots water ring vacuum units all adopt numerical control processing and 3D testing. The water ring vacuum pump test stand will make the testing equipment level of the units leading in China.
Rotor of water ring vacuum pump: it is cast as a whole, adopting resin sand casting process, avoiding the occurrence of casting defects such as sand inclusion and pore recessive cracks caused by traditional pulverized coal sand casting. Castings are fixed and melted to eliminate stress and ensure the rigidity of castings.
Semi-finishing (combined numerical control machine tool), impeller balancing experiment (balancing machine), impeller and shaft assembly, impeller and shaft use interference fit, finishing, impeller and pump shaft integration for mechanical finishing.
Rotz vacuum pump rotor
Three - blade involute line structure and high - precision machining to ensure smooth and quiet product operation.