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 in the condenser, the entry of steam and water into 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, drain pumps, and some low-pressure heaters, etc.) are in a vacuum state internally during normal operation.    Due to the loose pipes and casings, air leaks in, damaging 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 oxygen content in the condensed water, which intensifies corrosion of the thermal equipment and pipes. The presence of air also increases the heat transfer resistance in the absorber, affecting the cooling of the steam turbine exhaust by the circulating cooling water, and raises the factory's electricity consumption. Therefore, it is necessary to continuously extract air from the condenser during operation.

In summary, the vacuum system's function is to...①Establish condenser vacuum at the initial stage of the 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 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 Pumps

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 essentially the same principle; 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, since they all adopt the slide parameter startup method, there is no possibility of sufficient steam supply for the steam jet vacuum pump before the unit is started. Moreover, it is necessary to throttle high-pressure steam...1.2-1.6MPaPressure steam injection vacuum pumps are clearly very uneconomical, and to recover the working substance, a steam injection cooler also needs to be installed, which complicates the thermal system. Therefore, Currently, large capacity units in our country are all equipped with water injection vacuum pumps, which are mainly composed of working water inlet, working nozzle, mixing chamber, diffuser pipe, and check valve, etc.

Water-ring vacuum pump system. It consists of a water-ring vacuum pump, a water ring pump, a water ring tank, and connecting pipes. The exhaust from each low-pressure heater, condensate pump, and bleed pump are channeled into a condenser through exhaust pipes, which is connected to the working chamber of the water-ring vacuum pump. Water from the circulating water system or deep well is boosted to pressure by the water ring pump (one in operation, one as a backup) and then fed into the water-ring vacuum pump. The high-speed water jet ejected from the nozzle of the pump generates high vacuum in the chamber, extracting the gas-vapor mixture from the condenser. After expansion, this mixture returns to the water ring tank.

Three,Model Description

Section 4: Product and Component Matching Table