Decarburization pump incremental transformation

Abstract: Through the reformation of centrifugal pump impeller structure, increasing the flow, raising the lift, meeting the production requirements.

Key words: Centrifugal pump retrofit flow rate increase

The decarburization system in our workshop adopts the hot potash method to remove CO2 from the low volatility gas to provide a qualified hydrogen-nitrogen mixture for ammonia synthesis and at the same time provides CO2 gas with purity greater than 98% for urea production. The solution circulation mainly by decarbonization pump to provide energy.

Over the years, the system load is low, the required flow is less than 200m3 / h, far less than the design capacity of the pump 480m3 / h. In order to reduce power consumption, in 92 years its impeller cylindrical cutting, the effect is good. However, since the first phase of the 81 August fertilizer program was put into operation in 1999, the required flow rate increased to 240 m3 / h. According to the reconstruction team's calculation, the large pump impeller was restored to the original large impeller, basically meeting the production requirements at that time. When the second phase of fertilizer "8 · 13" was put into operation in 2001, the required flow rate increased to 280m3 / h. At this moment, the problem is exposed, the flow of large pump can not be increased any more, the liquid-liquid phenomenon appears in the atmospheric tower, Production is very unstable, the load is difficult to increase. In order to solve this bottleneck that restricts production, the workshop and the maneuver department formed a special research personnel.

improvement measures

Pump volute erosion wear problems, due to the difficulty of repairing, do not deal with. In order to reduce the backflow, strictly control the impeller wear ring and pump wear ring gap at 0.50 ~ 0.68mm, but at the same time on the pump shaft stiffness, straightness and the manufacturers conducted a coordinated, in strict accordance with the technical requirements. Such as quenching and tempering should be done to the regular manufacturers, and a written report. After each overhaul, should use the dial indicator to find the correct control tolerance is less than 0.05mm, to ensure that the pump shaft concentric with the motor shaft.

Reasonable deployment of system heat balance in production, as far as possible to reduce the temperature of imported lye, the maximum shall not exceed 108 ℃.

Aiming at the impeller structure problem, Yangzhou Lianxing Pump Co., Ltd. commissioned by the Department of Mechanical Engineering to recalculate the design without changing the assembly size in two steps. The first step is to improve the blade involute, Welded type, eliminating the bumpy inner surface after casting defect. The second step in the intensity of the allowable range of accounting, the appropriate reduction of the thickness of the blade and the front and rear cover, increasing the size of the entrance.

Transformation effect

After the new impeller put into operation, the operation is smooth and the effect is good. After the first improvement of the impeller structure, the flow rate is increased from 240m3 / h to 270m3 / h, basically meeting the production requirements. After the second improvement, the flow rate is increased To 310m3 / h, higher than the 280m3 / h currently required to sustain high-load production. In the case of unstable production, it is easy to adjust the process, increase the flexibility of operation, increase the capacity of absorbing CO2, eliminate the phenomenon of blocking the two towers and eliminate a big bottleneck of the restriction of the workshop control load. Foundation.