On the incrustation of marine boilers

Abstract

Pneumoconiosis and explosion accidents caused by coal dust are serious threats to workers in underground coal mines. Capturing dust with surfactant-magnetized water (SMW) is an efficient method to lower the coal dust concentration. To optimize the performance of a novel magnetized apparatus that used to improve the dust wetting features of the SMW, two self-constructed experimental systems were utilized to investigate the effects of the magnetized methods and magnetic parameters (magnetic intensity, relative velocity between water flow and a magnetic field, magnetized path) on the solution wettability. Experimental results showed that the coupling magnetic field formed by the pulsating magnetic field and spiral vortex could better improve the solution wettability. The SMW formed by the surfactant solution through an optimized magnetic apparatus (its magnetic intensity and path of 300–350 mT and 8 m) with the relative velocity between water flow and a magnetic field of 4 m/s has the optimal wettability, of which contact angle was reduced by 29.93% (to 23.97°) than that of the untreated solution, and decreased the surface tension to 26.37 mN/m. Additionally, the memory effect of surfactant-magnetized water was verified, i.e. the SMW wettability showed the attenuation trend after leaving from a magnetic field about 540 s. Field application indicated that a novel magnetic apparatus with the advantages of safe, reliable and compact size successfully produced the SMW to capture dust particles in the wind flow of the mining faces.