Product Details

I. Features

During the boiler startup process, when the steam turbine is heated by the steam, 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 up. The condenser and some low-pressure equipment (like condensate pumps, deaerating pumps, and some low-pressure heaters, etc.) are in a vacuum state internally when operating normally.    Due to the loose piping and casing, air leaks in, thereby 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, leading to a higher dissolved oxygen content in the condensate, which exacerbates corrosion of the thermal equipment and piping. The presence of air also increases the thermal resistance in the steam absorber, affecting the cooling of the steam turbine exhaust by the circulating cooling water, increasing the factory's electricity consumption. Therefore, air must be continuously extracted from the condenser during operation.

In summary, the vacuum system's purpose is:①Establish condenser vacuum at the initial stage of unit startup②Maintain the condenser vacuum during normal operation of the unit to ensure safe and economic operation. The main vacuum removal equipment for condensers includes vacuum pumps and exhaust blowers. The water jet vacuum 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 the 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 both having fundamentally similar principles; the only difference is 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, since they all use slide parameter startup methods, there is no possibility of having sufficient steam supply for steam jet vacuum pumps before the unit starts up. Additionally, it is necessary to use throttling from high-pressure steam to...1.2-1.6MPaPressure 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, 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, water-jet pump, water-jet tank, and connecting pipes. The exhaust from each low-pressure heater, condensate pump, and bleed pump is 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 boosted by the water-jet pump (one in operation, one as a spare) and then injected into the water-jet vacuum pump. The high-speed water jet emitted from the nozzle in the pump creates a high vacuum in the working chamber to extract the gas-vapor mixture from the condenser. This mixture is then expanded and returned to the water-jet tank.

Section 3:Model Description

IV. Product and Component Mating Table