Investigation on failure process and structural improvement of a high-pressure coal water slurry valve

The failure mechanism of a high-pressure coal water slurry valve in the coal chemical industry was investigated in this paper. Severe erosion wear was found on the valve spool, which threatened the safety and reliability of the unit. The mechanism was initially clarified by analyzing the technical process, operational condition and micro-morphology of corroded surface. Moreover, the failure process of valve spool is researched and the corresponding structural improvement was proposed via computational fluid dynamics (CFD) methodology. The numerical simulation was performed by using actual running and fluid physical parameters. The results showed that the serious erosion wear was both found on the valve spool and valve bushing. Specially, the maximum erosion rates locate on the top of spool head. The numerical results are in good agreement with the actual failure morphology, then the numerical calculation is verified. The improved structure of valve spool and downstream pipeline is proposed. The field test proved that the erosion wear of valve spool was significantly reduced, thus the service life of the valve was extended.