How to use chemical pump to save energy?

1 Improve the maintenance process of feed water pump to reduce hydraulic loss

1.1 improve runner finish

During maintenance, the rust, scale, burr and flash of the impeller and the circulation part of the blade channel shall be polished to make the smoothness of the flow channel reach more than △ 4, and the friction impact vortex loss between water and the flow channel wall surface shall be reduced. However, limited by the site conditions, it is not easy to polish the whole flow part. Focus should be on the key parts that affect the efficiency, such as the positive guide blade part, the inlet part of the impeller, the outlet part of the impeller, etc. Grinding to see the metallic luster can be, must not destroy the original flow line.

1.2 Improve the smoothness of the outer wall of the impeller and the inner wall of the pump casing. During maintenance, the embroidered dirt and burrs on the outer wall of the impeller and the inner wall of the pump casing are polished and smooth, while keeping the deflection of the impeller not exceeding the specified value, so as to reduce the friction loss of the disc.

1.3 reduce the impact loss of the impeller outlet

In the handling of the flow center of the impeller and guide vane, the flow passage of the impeller shall not exceed the flow passage of the guide vane, and the outlet of the impeller shall be free of burrs and flash. During installation, the axial size of the rotor and the pump casing should be controlled within the allowable range. The axial displacement of the pump reflects the difference between the impeller and the guide vane at all levels. During normal operation, the axial displacement of the pump should be controlled. Reduce the impact loss of the impeller outlet fluid.

2 Reduce volume loss and improve operating efficiency

(1) Reduce the leakage loss in the pump, improve the machining accuracy and assembly quality of the parts, reduce the radial clearance of the throttle bushing in front of the balance disc and the radial clearance of the front and rear sealing rings of the impeller and the guide vane sealing rings, and reduce the liquid in the pump Pressure energy loss caused by leakage from the high pressure side to the low pressure side. The impeller seal ring, guide vane sleeve, balance disc front throttle and other components should be selected high hardness materials, and improve the wear resistance of heat treatment.

(2) When starting the feed water pump in cold state, the pump shall be fully warmed according to the requirements of the regulations. If the pump is not fully warmed, a large thermal temperature difference between the upper and lower parts of the pump body is easy to produce bow deformation of the rotor. At this time, starting the pump is easy to make the internal sealing gap wear large, resulting in increased internal leakage and return volume loss.

(3) During operation, carefully monitor the axial movement of the pump and the change of the discharge pressure after the balance plate. During normal operation, the discharge pressure after the balance plate should be overhauled in time when the large-scale change of the inlet pressure of the pump is large, so as to reduce leakage loss and improve the volumetric efficiency of the pump.

(4) when adjusting the load, it should be stable to avoid large fluctuations in the feed water pressure, maintain the continuous and stable operation of the feed water pump, and reduce the axial movement of the pump to avoid wear of the seal gap.

3 Reduce the leakage loss of water supply system

(1) Under normal operation, the drain valve, drain valve and pump body drain valve of the water supply system, the regular blowdown valve of the boiler and the accident drain valve should be closed tightly, and the door should be cool after being touched by hand. If the valve is not strict, it should be handled in time.

(2) Reduce the leakage loss of the recirculation valve of the feed pump. The feed water pump recirculation device is used to keep the feed water pump start, just put into operation, stop the boiler water supply to maintain a ZUI small flow, in order to prevent the operation due to small flow and heat, feed water vaporization, resulting in accidents. The recirculation door shall be closed tightly during normal operation. In the field, due to structural and material problems, the recirculation door generally leaks seriously under the scouring action of a large pressure difference, and a large amount of high-pressure feed water returns to the deaerator for useless work, resulting in waste of electric energy and even affecting boiler feed water. At this time should be timely exit from the operation, repair the leakage of serious recirculation door, to maintain its good tightness. In addition, when starting the feed water pump, when the pump is running normally, the recirculation door should be closed in time to reduce the power loss at this time.

(3) The outlet check valve of the standby feed water pump shall be tight, and the outlet valve of the feed water pump of the input linkage standby water pump is generally in the open state. If the backstop valve is not tight, the high-pressure feed water leaks back to the deaerator through the pump body, and even causes the standby pump to reverse. The standby pump should be withdrawn immediately for treatment, which not only reduces the pressure energy loss of the high-pressure feed water, but also ensures the safe standby of the equipment. In addition, in the case of meeting the needs of water supply, only the outlet door of the feed pump can be kept in the fully open state for standby, and the outlet doors of other standby pumps can be closed to reduce leakage losses.

4 Application of variable frequency controller

The variable frequency speed regulation operation of the water pump means that the water pump is driven by an adjustable speed motor, and the operating point of the water pump device is changed by changing the speed. This greatly expands the effective working range of the pump and is a very important and applicable adjustment method in the project. At present, the electric energy consumed by the motor accounts for about 65% of the industrial power consumption, and the motor used by the vast majority of equipment is still a general non-adjustable speed motor. If these non-adjustable speed motors are transformed into adjustable speed motors, and their power consumption changes with the load, a lot of electric energy can be saved. By the principle of centrifugal pump, under similar circumstances, the flow, head and power of the pump are proportional to the first, second and third power of its speed. For the occasion of frequent changes in water, the use of variable frequency speed pump water supply, can significantly reduce the throttle loss, with obvious energy saving effect.