Research on closed spray injection purification and dust removal technology at coal mine belt transfer point

To address the issues of high dust concentration at coal mine belt transfer points and the insufficient efficiency of existing dust suppression technologies, a closed-type spray-induced jet purification and dust removal technology is proposed. This technology integrates a coal baffle plate, an arched enclosed hood, and a double-flared-mouth jet ejector to create an enclosed environment, thereby minimizing dust leakage. The ejector generates a negative pressure zone through high-pressure water spray, drawing dust-laden airflow into the ejector throat. The collision and coalescence of fog droplets with dust particles facilitate wetting and sedimentation, while the secondary negative pressure expands the dust suppression range, forming a synergistic mechanism of “enclosed environment + negative pressure induction + fog droplet capture”. This approach surpasses the efficiency limitations of traditional spray dust suppression methods, enhancing dust capture efficiency. Initially, the effectiveness of the dust removal technology of the physical model of corresponding device was validated through numerical simulations based on the Standard k-ε turbulence model and the Taylor analogy breakup (TAB) model, revealing its notable dust removal capabilities. A positive correlation was observed between spray pressure and induced airflow volume, with higher spray pressures yielding better dust removal results. Building on this, a nozzle performance testing platform was developed to systematically investigate the induced airflow volume patterns of five nozzle types under varying pressures. The nozzle with the optimal induced jet efficiency was selected and paired with the closed-type spray-induced jet dust removal device for field application verification at a coal mine underground transfer point. The dust suppression efficiency of three methods (enclosed device only, enclosed + conventional spray, and enclosed + induced spray) was compared by sampling and analyzing the dust concentration at the air outlet. The application results indicated that the closed-type spray-induced jet purification and dust removal device, operating at a pressure of 6 MPa, reduced the total dust mass concentration at the transfer point from 155.33 mg/m³ to 8.67 mg/m³, achieving a dust suppression efficiency of 94.42%, which significantly outperformed other dust removal methods. The study shows that through multi-physical field coupling effects, this technology can markedly enhance dust capture efficiency, offering an innovative solution for dust management at coal mine transfer points and demonstrating substantial engineering application value.