Because the pH of chemically desalinated water is generally between 6 and 7, and it is water that has not been deoxygenated. Therefore, it is basically a kind of slightly acidic water containing oxygen, which has a strong corrosive effect on the hollow copper wires of the generator stator coil, so it is not advisable to add too much. This requires that when replacing the cold water from the generator, the condensed water and the desalinated water are added at the same time.
Steam Turbine Condensate System Overview
I will express my opinion. You must know the exhaust emissions caused by the unit under normal conditions (that is, non-accidental conditions). severe conditions of vacuum system leakage and fan friction). The condenser vacuum and turbine exhaust steam temperature correspond to the high steam temperature state. The more the voidhigher, the lower the exhaust gas temperature. This is determined by the principle of operation of the steam turbine. To put it simply, the saturation temperature and vapor pressure match perfectly. For example: water boils at 100°C under atmospheric pressure. But as the pressure increases, the boiling temperature increases. Likewise, as the pressure decreases, the boiling temperature also decreases. Just like on the Qinghai-Tibet Plateau, water can boil at 80 degrees Celsius. Ideally, in the condenser of the steam turbine, the working fluid (steam-water) is in a balanced state, that is, the cooling water flowing into the condenser only removes the latent heat of vaporization of the steam and does not cool the steam. This is our ideal state, without hypothermia. At this time, the corresponding temperature of the condenser should be the corresponding saturation temperature of the water sous the absolute pressure of the condenser. That said, I just want to change one of your misunderstandings: to lower the exhaust steam temperature, you just need to increase the condenser vacuum. This doesn't mean that lowering the exhaust steam temperature will increase the vacuum like you think. is a cause and effect relationship. If you understand this problem, I will give you some simple and effective ways to increase vacuum. 1. Try to increase the amount of cooling water in the condenser. If the circulating water temperature is high in summer, various power plants use a common method to increase the circulating water pump. 2. If it is a closed circulating water system cooled by a cooling tower, the inlet water flow of the circulating water tower can be increased and the inlet temperature of the condenser cooling water can be reduced. If the cooling toweridissement has a backup water source, it is better to use deep underground well water because the temperature of deep well water is low. 3. Check the condenser vacuum for tightness and eliminate leaks. 4. If a waterjet steam extractor is used, try to lower the water temperature in the waterjet tank to below 35°C.
As the most important condensing equipment of the condensing steam turbine unit, the condensate system of the steam turbine is responsible for establishing and maintaining a high vacuum at the exhaust port of the steam turbine to condense the exhaust steam into water. The condensed water is pumped to the deaerator to form feedwater for the boiler; The condenser vacuum quality will directly affect the normal operation of the unit. It can be said that the quality of the condenser operation will directly affect the safety.security of the device. steam turbine unit, economical and efficient operation.
As the exhaust steam discharged from the steam turbine is cooled and condensed into water, its specific volume decreases sharply. For example, when the absolute pressure of steam is 4 Kpa, the volume of steam is more than 30,000 times the volume of water. When the exhaust vapor condenses into water, the volume is greatly reduced, causing a high vacuum to form in the condenser. .
ExtensionInformation:
The function of the water turbine condensate water system steam:
It is a heat exchanger that converts the steam discharged after rolling the steam turbine into the condensing water equipment. After the steam completes its expansion process in the steam turbine, during the condensation process, the volume of the exhaust steam decreases fort and a high vacuum is formed in the space initially filled with steam. The condensate water is transported into the boiler via the condensate water pump through the feed water heater, feed water pump, etc., thus ensuring the continuous running of the entire thermal cycle. Its functions are as follows:
1. Create a higher vacuum at the exhaust port of the steam turbine. The steam expands to the lowest pressure in the steam turbine, increases the available enthalpy drop of the steam in the steam turbine, and improves the thermal efficiency of the cycle.
2. Condense the steam discharged from the low pressure cylinder of the steam turbine into water and return it to the boiler for circulation.
3. Collect various hydrophobic materials to reduce the loss of carbonated water.
4. The condenser is also used to add desalinated water (normal water replenishment).At).
Baidu Encyclopedia - Main condensate water purification system
Baidu Encyclopedia - Condensate water purification system