Product Details
I. Features
During the boiler start-up process, when the steam turbine is warmed up by the boiler's ignition, more steam will enter the condenser. If a certain vacuum is not established within the condenser, the entry of steam and water will cause the condenser to develop positive pressure, damaging the equipment. Establishing a vacuum in the condenser is an indispensable condition for the steam turbine to start. Condenser and some low-pressure equipment (like condensate pumps, drainage 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, thus destroying the vacuum of the condenser and posing a risk to the safe and economic operation of the steam turbine. At the same time, the partial pressure of air in the condenser increases, causing an increase in the oxygen content of the condensate, which intensifies corrosion of the thermal equipment and pipes. The presence of air also increases the heat transfer resistance in the vacuum receiver, affecting the cooling of the steam turbine exhaust by the circulating cooling water, increasing power consumption, and therefore, air must be continuously extracted from the condenser during operation.
In summary, the vacuum system's purpose is:①Establish condenser vacuum at the early stage of unit startup②Maintain the condenser vacuum during normal operation of the unit to ensure safe and economic operation. The main equipment for vacuum extraction in the condenser includes vacuum pumps and vacuum ejectors. The water jet vacuum ejector system is widely used in domestic large and medium-sized units due to its simple design and reliable operation.
Section 2: 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 period of time. Jet vacuum pumps can be divided into steam jet vacuum pumps and water jet vacuum pumps based on the working medium, with the basic principle of both being the same; the difference lies in the working medium. The working medium of a steam jet vacuum pump is pressurized steam, while for a water jet vacuum pump, it is pressurized water. Small capacity units often 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 having sufficient steam supply for the steam jet vacuum pump before the unit starts up. Moreover, it is necessary to throttle high-pressure steam to1.2-1.6MPaPressure steam injection vacuum pumps are clearly uneconomical, and to recover the working fluid, a steam injection cooler must also be installed, which complicates the thermal system. Therefore, Our large-capacity units in China are all equipped with water-ring vacuum pumps, which are primarily composed of the working water inlet, working nozzle, mixing chamber, expansion tube, and check valve, among other components.
Water jet vacuum pump system. It consists of a water jet vacuum pump, a water jet pump, a water storage tank, and connecting pipes. The exhaust from each low-pressure heater, the condensate pump, and the drain pump are collected through exhaust pipes and fed into a condenser, which is connected to the working chamber of the water jet vacuum pump. Water from the circulating water system or deep well is pressurized by the water jet pump (one in operation and one as a standby), then injected into the water jet vacuum pump. The high-speed water jet emitted by the nozzle in the pump generates a high vacuum in the working chamber to extract the gas and vapor mixture from the condenser. After expansion, this mixture returns to the water storage tank.
Section 3:Model Description
Section 4: Product and Component List
