Steam Jet Vacuum Pump

Product Details

I. Features

During the unit start-up process, when the boiler ignites and the steam turbine is warmed up, 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 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, 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破坏ing the vacuum of the condenser and threatening 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 heat transfer resistance in the steam absorber, affecting the cooling of the steam turbine exhaust by the circulating cooling water, increasing the power consumption of the plant. Therefore, it is necessary to continuously remove air from the condenser during its operation.

In summary, the vacuum system's purpose is:①Establish condenser vacuum at the initial stage of unit startup②Maintain the condenser vacuum during normal unit operation to ensure the safe and economic operation of the unit. The main equipment for vacuum extraction in the condenser includes vacuum exhausters and vacuum pumps. The water-jet vacuum exhauster system is widely used in domestic large and medium-sized units due to its simple system and reliable operation.

Section II: Structure and Working Principle of Water Jet Vacuum Pump

In modern power plants, jet vacuum pumps are widely used due to their compact layout, simple structure, easy maintenance, reliable operation, and the ability to establish the required vacuum quickly. Jet vacuum pumps can be divided into jet steam vacuum pumps and jet water vacuum pumps based on different working media. Both types of vacuum pumps operate on the same principle, with the only difference being the working medium. The working medium for a jet steam vacuum pump is pressurized steam, while for a jet water vacuum pump, it is pressurized water. Small capacity units mostly use jet steam pumps. For high-parameter, large-capacity units, since they all use slide parameter start-up methods, there is no possibility of having enough steam supply for the jet steam vacuum pump before the unit starts. Moreover, it is necessary to use throttling from high-pressure steam to...1.2-1.6MPaThe steam jet vacuum pump under pressure is obviously uneconomical, and to recover the working fluid, a steam jet cooler must also be installed, which complicates the thermal system. Therefore, Currently, our large-capacity units all use 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 storage tank, and connecting pipes. The exhaust from each low-pressure heater, the condensate pump, and the drain pump are collected through exhaust pipes into a condenser, which is connected to the working chamber of the water jet vacuum pump. Water from the water storage tank, sourced from circulating water or a deep well, is pressurized by the water jet pump (one in operation and one standby) before being 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, thereby extracting the gas-vapor mixture from the condenser. After expansion, this mixture returns to the water storage tank.

III.Model Description

Section 4: Product and Component List