Product Details
I. Features
During the engine start-up process, when the boiler ignites and the steam turbine is heated by the incoming steam, more steam will enter the condenser. If a certain vacuum is not established within the condenser, the entry of steam and water into the condenser will cause the condenser to form positive pressure, damaging the equipment. Establishing a vacuum in the condenser is an essential condition for the steam turbine to start rotating. The condenser and some low-pressure equipment (like condensate pumps, deaerating pumps, and some low-pressure heaters, etc.) are in a vacuum state internally during normal operation. Due to the imperfect tightness of the pipes and shells, air leaks in, thereby破坏ing the vacuum of the condenser and endangering the safe and economic operation of the turbine. At the same time, the partial pressure of air in the condenser increases, leading to an elevated dissolved oxygen content in the condensate, which intensifies corrosion on thermal equipment and pipes. The presence of air also increases the thermal resistance in the heat exchanger, affecting the cooling of the turbine exhaust by the circulating cooling water, thus increasing the factory's electricity consumption. Therefore, it is necessary to continuously remove air from the condenser during its operation.
In summary, the vacuum system's function is to...①Establish condenser vacuum at the initial stage of unit startup②Maintain the condenser vacuum during normal unit operation to ensure safe and economical operation of the unit. The main equipment for vacuum extraction of the condenser includes vacuum pumps and vacuum exhausters. The water jet vacuum exhauster system is widely used in domestic large and medium-sized units due to its simple design and reliable operation.
Section II: Structure and Working Principle of Water Jet Vacuum Pump
In modern power plants, the widely used vacuum pump is the jet vacuum pump, which boasts compact layout, simple structure, easy maintenance, reliable operation, and the ability to establish the required vacuum in a short time. Jet vacuum pumps can be categorized into steam jet vacuum pumps and water jet vacuum pumps, both of which operate on the same principle but differ in the working medium. The working medium for steam jet vacuum pumps is pressurized steam, while for water jet vacuum pumps, it is pressurized water. Small capacity units mostly use steam jet vacuum pumps. For high parameter, large capacity units, due to the use of slide parameter startup methods, there is no possibility of sufficient steam supply for steam jet vacuum pumps before the unit starts up. Moreover, it is necessary to throttle high-pressure steam to1.2-1.6MPaThe steam ejector with pressure supply is obviously very uneconomical, and in addition, a steam ejector cooler needs to be installed for the recovery of the working substance, which also makes the thermal system very complicated. Therefore, Currently, large-capacity units in our country are equipped with water jet vacuum pumps, which are mainly composed of working water inlet, working nozzle, mixing chamber, diffuser, and check valve, etc.
Water-jet vacuum pump system. It consists of a water-jet vacuum pump, a water-jet pump, a water-jet tank, and connecting pipes. The exhaust from each low-pressure heater, the condensate pump, and the bleed pump are channeled into the condenser via exhaust pipes, which is connected to the water-jet vacuum pump's working chamber. Water from the circulating water system or deep well is pressurized by the water-jet pump (one in operation, one as a standby) and then injected into the vacuum pump. The high-speed water jet emitted by the nozzle in the pump creates a high vacuum in the working chamber, thereby extracting the gas-vapor mixture from the condenser. This mixture is then expanded and returned to the water-jet tank.
III.Model Description
IV. Product and Component Mating Table
