Turbine Extractor

Product Details

I. Features

During the unit start-up process, when the boiler ignites and the steam turbine is heated, more steam will enter the condenser. If a certain vacuum is not established within the condenser, the steam and water entering the condenser will cause the condenser to form 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, deaeration pumps, and some low-pressure heaters, etc.) are in a vacuum state internally during normal operation.    Due to the loose piping and shell, air leaks in, thereby破坏 the vacuum of the condenser and endangers the safe and economic operation of the steam turbine. Simultaneously, the partial pressure of air in the condenser increases, leading to a higher oxygen content in the condensate, which exacerbates corrosion on thermal equipment and pipes. The presence of air also increases the heat transfer resistance in the steam absorber, affecting the cooling of the steam turbine exhaust by the circulating cooling water, thus increasing the power consumption of the plant. Therefore, it is essential to continuously remove the air from the condenser during its operation.

In summary, the vacuum system's purpose is:①Establish condenser vacuum in the early stages of the unit start-up②Maintain the condenser vacuum during normal unit operation to ensure safe and economic operation of the unit. The main equipment for vacuum extraction in the condenser includes vacuum pumps and exhaust blowers. The water jet vacuum extraction system is widely used in domestic large and medium-sized units due to its simple system 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 are divided into steam jet vacuum pumps and water jet vacuum pumps based on the working medium, with the basic principles of both being the same; the difference lies 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. Additionally, it is necessary to throttle high-pressure steam to1.2-1.6MPaPressure steam injection vacuum pumps are clearly very uneconomical, and in order to recover the working substance, a steam injection cooler also needs to be installed, which complicates the thermal system. Therefore, Currently, our country's large capacity units all use water jet vacuum pumps, which are mainly composed of working water inlet, working nozzle, mixing chamber, expansion pipe, and check valve, etc.

Water Jet Vacuum Pump System. It consists of a water jet vacuum pump, water jet pump, water jet 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 the 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) and then injected into the water jet vacuum pump. The high-speed water jet emitted by the nozzle in the pump creates a high vacuum in the working chamber, extracting the gas-vapor mixture from the condenser. After expansion, this mixture returns to the water jet tank.

Section 3:Model Description

4. Product and Component Matching Table