Environmental protection equipment - Self-excited wet dust collectors use nozzles to spray water mist, which directly contacts the dust-laden air. Dust separation is achieved through the adsorption, collision, and agglomeration of droplets. The rationality of nozzle layout directly affects the water mist coverage, droplet distribution uniformity, and gas-liquid contact efficiency, which in turn determines dust removal effectiveness. Optimizing nozzle layout requires comprehensive improvements in nozzle type selection, spatial distribution design, spray angle adjustment, and dynamic coordinated control.
Nozzle selection must balance atomization performance and adaptability to operating conditions. Solid-cone nozzles produce a uniform, solid water mist cone, suitable for precise coverage of localized high-concentration dust. Hollow-cone nozzles form a hollow water mist ring, suitable for handling dust in circular airflows. Fan-shaped nozzles produce a flat water curtain, suitable for lateral interception of wide airflows. For example, when handling high-temperature flue gases, high-temperature-resistant ceramic nozzles can prevent thermal deformation. For corrosive gases, stainless steel or engineering plastic nozzles can extend service life. In practical applications, a combination of nozzles is often used. For example, fan-shaped nozzles are placed at the inlet of a self-excited wet dust collector to form an initial water curtain and intercept large dust particles; solid cone nozzles are installed in the middle to achieve deep purification; and hollow cone nozzles are installed at the outlet for supplementary cleaning, forming a gradient dust removal system.
The spatial distribution design must ensure that the water mist completely covers the airflow path. In the vertical layout, nozzles should be arranged in layers, with each layer height determined by airflow velocity and water mist settling time, typically spaced 0.5-1.5 meters apart, to prevent the upper layer of water mist from being carried away by the lower layer of airflow before it fully contacts the dust. The horizontal layout must also consider airflow uniformity. For circular self-excited wet dust collectors, nozzles should be evenly spaced along the circumference. For rectangular self-excited wet dust collectors, a matrix layout is used, with nozzle spacing 1.2-1.5 times the effective spray radius to ensure that adjacent water mists do not overlap. For example, in a sintering machine exhaust gas treatment project at a steel plant, by switching from a single-layer, four-nozzle layout to a double-layer, eight-nozzle cross-layout, water mist coverage increased from 75% to 92%, while reducing dust emission concentration by 40%.
Adjusting the spray angle directly affects the probability of droplet-dust collision. While vertical spraying creates a stable water curtain, it creates significant airflow resistance. Angle spraying reduces pressure drop, but requires precise angle control to prevent mist deflection. Typically, a 30°-60° angle is used to create an angle between the droplet motion and the airflow, extending contact time. For cyclonic environmental protection equipment (EPE) self-excited wet dust collectors, nozzles should be arranged tangentially to synchronize the water mist with the rotating airflow, enhancing dust separation under centrifugal force. During a fluidized bed boiler dust removal retrofit at a chemical company, switching from vertical spray nozzles to a 45° tangential arrangement reduced system pressure drop by 15% and increased dust removal efficiency by 8%.
Dynamic coordinated control is key to improving adaptability to complex operating conditions. By installing flow meters, pressure sensors, and particulate matter monitors, real-time data on gas-liquid flow, pressure, and dust concentration is collected. A PLC system dynamically adjusts the number of nozzles open and the spray pressure. For example, if dust concentration suddenly rises, the system automatically increases the number of active nozzles and increases the water pressure to enhance water mist capture. When the airflow temperature fluctuates, the nozzle cooling water flow is adjusted to maintain an optimal liquid-to-gas ratio. After implementing an intelligent control system in a waste incineration plant's flue gas treatment system, the system maintains a dust removal efficiency of over 98% despite fluctuating operating conditions, a 12% improvement over the traditional fixed system.
Nozzle maintenance is also crucial. Regularly check for nozzle blockages and unclog the orifices with high-pressure water jets or chemical cleaning agents. Test the spray angle and atomized particle size quarterly, and replace worn nozzles promptly. In winter, the sprinkler system should be equipped with a heating device to prevent water mist from freezing and affecting performance. These measures ensure that the nozzles remain in optimal working condition over the long term, providing a stable guarantee for dust removal efficiency.
