Product Details

I. Features

During the startup process of the unit, 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 up. 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 lack of tightness in the pipes and shells, air leaks in, thereby破坏 the vacuum of the condenser and threatens the safe and economic operation of the steam turbine. At the same time, the partial pressure of air in the condenser increases, leading to a higher dissolved oxygen content in the condensate, which intensifies corrosion on the thermal equipment and pipelines. The presence of air also increases the thermal resistance in the heat exchanger, affecting the cooling of the steam turbine exhaust by the circulating cooling water, thereby increasing the factory's power consumption. Therefore, air must be continuously extracted from the condenser during its operation.

In summary, the vacuum system's function is to①Establish condenser vacuum during the initial startup of the unit②Maintain the condenser vacuum during normal operation of the unit to ensure safe and economic operation. The main equipment for vacuum extraction in condensers 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 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 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 the steam jet vacuum pump is pressurized steam, while the working medium of the water jet vacuum pump 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 sufficient steam supply for the steam jet vacuum pump before the unit starts up. Additionally, it is necessary to throttle high-pressure steam...1.2-1.6MPaPressure steam injection vacuum pump is clearly uneconomical, and to recover the working fluid, a steam injection cooler also needs to be installed, which makes the thermal system very complex. 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, expansion tube, 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 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 backup) 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, thereby extracting the gas-vapor mixture from the condenser. This mixture is then expanded and returned to the water jet tank.

3.Model Description

Section 4: Product and Equipment Matching Table