Main Types of Venturi Wet Scrubbers: Packed, Jet, Variable Throat, Multi-Vane, and More

Jet Venturi Scrubber is engineered for purification, utilizing a high-velocity solution flow to create a low-pressure zone that captures contaminated emissions. In this system, nozzles inject the liquid at high speeds, forming fine droplets that interact with the airflow. These droplets capture dust particles, aerosols, and volatile impurities.

In ejector-type equipment, the exhaust stream is drawn in by the energy of the fluid creating a vacuum. In contrast, the venturi jet scrubber captures it through the flowing medium, but the emulsion is injected at such high speeds that it generates fine droplets for contaminant capture without creating a vacuum effect. This form of device is able to operate without a mechanical compressor or fan, as the medium is drawn into the system by the energy of the liquid.

The water jet scrubber can handle high-temperature effluent and withstand corrosive environments due to the use of chemically resistant materials, such as polypropylene, PVC, and various grades of stainless steel. It also provides a high level of phase contact, enabling effective removal of acidic substances such as SO₂ and HCl. The jet venturi scrubber design necessitates precise calculations of nozzle diameters, liquid velocities, and airstream volumes to achieve optimal performance.

This structure combines the functionality of a venturi technology with a packed section to enhance phase interaction. Initially, the airstream passes through a standard scrubber quench venturi system, where it is accelerated, mixed with liquid, cooled, and particles are captured through inertial impaction.

The mixture then enters a packed bed column, where it flows through packing material that provides an extensive surface area for phase contact. This stage is essential for the successful removal of soluble gaseous pollutants, such as sulfur and nitrogen oxides.

The main advantage of this design is its versatility: it can handle both particulate matter and volatile contaminants of various types. It is one of the most efficient treatment configurations available. This equipment is commonly used in aggressive chemical processes, such as sulfuric acid production, and in oil refineries, where emissions include solid particles like ash, carbon, and catalyst dust, along with soluble gases like sulfur and nitrogen oxides, hydrogen sulfide, and ammonia.

The Variable Throat Venturi Scrubber is a specialized apparatus featuring an adjustable throat width, which allows it to adapt to changing airflow conditions. The primary distinguishing characteristic of the devices is its ability to modify the throat geometry, which enables the maintenance of optimal gas velocities and pressures based on the current volume and composition of the stream, all without the need for multi-venturi scrubber setups.

Such a design is crucial in areas where airflow parameters may vary significantly. For example, in fuel combustion processes—such as those in coal-fired power plants—the volumes and compositions of contaminated medium might change dramatically depending on the types of fuel used and the operating conditions of the boilers. In cement production, ventilation flows and dust levels are able to fluctuate greatly depending on the stage of the process (calcination, grinding, packaging). In these scenarios, the variable throat allows the system to effectively manage changing conditions, enhancing dust removal and ensuring compliance with emission requirements.

This type of venturi scrubber is typically equipped with a mechanism for automatic adjustment of the throat position, reducing the need for constant manual monitoring.

The MVS (Multi-Vane Scrubber) is a specific type of Venturi scrubber. It is a device that incorporates multiple vanes within the throat to generate a turbulent flow. These vanes are fixed at specific intervals and positioned at an angle. As the contaminated mixture passes through the narrowing section of the unit, the stream velocity increases, and pressure decreases. The vanes create additional vortex flows, enhancing the mixing of gases with the liquid. This results in fine reagent droplets being more effective at capturing the contaminants present. Consequently, MVS setups are more versatile and efficient compared to traditional configurations, which lack such additional elements for creating turbulence.

Additionally, the vane design can be tailored to optimize flow for each specific application, taking into account the characteristics of the medium being treated, the types of pollutants, and the required system performance.

Ejector Venturi Scrubber is constructed for purifying airflows by employing the injection effect to capture contaminated vapors. A notable feature is the absence of a mechanical fan; instead, the flow is generated by the energy of the injected medium. High-velocity nozzles introduce the liquid, creating a vacuum that draws the contaminated stream into the throat, along with fine particulate matter and gaseous impurities.

The ejector venturi gas scrubber is widely used in situations where mechanical fans are undesirable or impractical for various reasons. This can include high operational costs associated with fans, particularly in aggressive environments where they are prone to corrosion or mechanical wear. For example, in chemical and petrochemical plants, operators often deal with aggressive vapors that have the potential to quickly damage moving parts of equipment. In these conditions, this kind of equipment provides a solution by generating airstream through the energy of high-velocity solution, eliminating the need for moving parts and reducing the risk of breakdowns. This approach simplifies maintenance and enhances the reliability of the system.

Purifiers of this variety are capable of operating continuously at high temperatures or in areas with hazardous emissions, where any workflow failure could lead to serious consequences. For instance, they efficiently treat exhaust streams from waste incineration processes, removing ash particles, toxic compounds, and minimizing odors.

The Multi-Venturi Wet Scrubber uses multiple elements for air cleaning. Typically, the scrubbing sections operate in parallel, allowing the multi-venturi scrubber system to handle large gas volumes and increase the overall contact surface area between phases, compared to using a larger single unit. In some designs, the sections can be arranged to operate in series, though this is less common. A series configuration may be employed in situations where a stepwise reduction of contaminant concentrations is required. In this case, the contaminated medium passes through one section and then another, allowing for more thorough treatment, but this may also increase liquid consumption and processing time. However, such setups are relatively rare.