Research On The Angle Type Black Water Control Valve With Long Cycle Life And Better Erosion Resistance

In the gasification section of coal chemical industry, the black water control valve is important equipment in controlling the pressure and liquid level of black water. In a very short period of time, the common control valve always loses efficacy on account of serious erosion, large leakage and poor controlling performance caused by the black water with impurities, high temperature, serious corrosively and high pressure drop. Although some valve enterprises develop the control valve specially designed for the black water, the cycle life is only about 3 months because of trim failure resulted from serious erosion. Frequent replacement in the black water control valve has seriously affected the regular production of coal chemical industryThis paper presents the primary factor of valve failure induced by high velocity of throttling parts between the valve plug and valve seat. A model of an angle type black water control valve(model one) is established whose inlet and outlet nominal diameters are 3 inches and 4 inches respectively, and pressure class is 600 LB. The flow velocity and pressure are analyzed by CFD at different openings. By the optimization of model one, a new model(model two) can be also established and analyzed by CFD. Compared with model one, a lower velocity can be obtained from model two in the same opening to improve the valve’s erosion resistance and cycle life. To verify the reliability of data analyzed by CFD, prototypes of two valves(model one and model two) are manufactured and practical tests about prototypes are conducted. This paper mainly presents the following 4 aspects:(1)Introducing the working condition and installing location of the black water control valve and discussing its properties. Concluding the problems existing in the black water control valve and its current development situation.( 2) Introducing basic theories and methods of numerical simulation and frequently-used commercial CFD software. Discussing two-dimensional drawings and three-dimensional models of the original model(model one) and optimized model(model two) and simplifying both models from the point of hydromechanics.(3)Comparing the velocity fields and pressure fields of seventeen examples of both models in small opening, common opening, large opening and full opening to conclude advantages of model two.(4)Producing prototypes with trims of both models and testing the flow respectively. Comparing the testing and simulated results to validate the reliability and accuracy of is CFD simulation. Particularly analyzing the differences between simulated and measured valuesCompared to model one, the valve plug and valve seat designed in model two can decrease the fluid speed drastically under the condition of ensuring the rated Cv and prolong the cycle life to satisfy production needs and reduce maintenance costs.