High-Efficiency Gas Cleaning with Controlled Liquid Use

Wet gas scrubbers are highly effective gas cleaning systems capable of removing a wide range of gaseous pollutants and, depending on configuration, particulate matter. Their performance is based on intensive gas–liquid contact, where pollutants are transferred from the gas phase into a circulating absorption liquid.

During operation, the process gas is cooled adiabatically to its wet-bulb temperature, in line with psychrometric principles and enthalpy balance. Part of the scrubbing liquid evaporates in this step, creating inherent liquid losses through evaporation and potential droplet carry-over. Effective liquid management is therefore a core design and operational consideration.

Mass Transfer and Liquid Saturation

The absorption process is governed by fundamental mass transfer principles. Pollutants migrate from the gas phase into the liquid phase according to concentration gradients, as described by diffusion theory. In applications requiring enhanced absorption rates or higher removal efficiencies, chemical additives may be introduced into the scrubbing liquid to enable reactive mass transfer. These reactions follow defined chemical kinetics and significantly influence overall system performance.

As the scrubbing liquid is recirculated through the absorption column, it gradually becomes saturated with absorbed contaminants and reaction products. This accumulation affects absorption capacity and process stability, making controlled liquid renewal essential for consistent emission performance.

Liquid Quality as a Key Emission Parameter

The quality of the treated gas is directly linked to the condition of the absorption liquid. There is a strong correlation between liquid purity and emission quality: a well-conditioned scrubbing liquid results in higher gas purity and more stable outlet concentrations.

For this reason, continuous monitoring of both gas composition and liquid condition is essential. Maintaining optimal thermodynamic and mass transfer conditions ensures reliable compliance with emission limits while avoiding unnecessary liquid consumption.

Purge, Replenishment, and Wastewater Handling

To maintain performance, a defined portion of the scrubbing liquid is periodically purged and replaced with fresh liquid. This operating regime follows the law of conservation of mass and ensures that contaminant concentrations in the liquid remain within acceptable limits.

Purged liquid typically requires treatment before discharge, in accordance with environmental regulations and site-specific wastewater standards. The design of the purge and treatment concept is therefore an integral part of the overall scrubber system.

Liquid Consumption Optimization Strategies

Ravebo works closely with clients to minimize liquid consumption without compromising gas cleaning efficiency. Key optimization measures include:

• Gas-based process control
  Continuous monitoring of outlet gas composition is used as the primary control parameter to prevent excessive liquid usage.
• Countercurrent liquid management in multi-stage scrubbers
  Transferring scrubbing liquid from the final stage to upstream stages maintains a favorable concentration gradient, improving absorption efficiency and preserving driving force across the system.
• Solid–liquid separation and filtration
  Depending on particle size distribution and chemical load, solutions such as vacuum belt filters, clarification or decantation units, and duplex filtration systems are applied to extend liquid lifetime.
• Thermal optimization
  Where process conditions allow, external cooling of the scrubbing liquid can be implemented to reduce evaporation losses, consistent with vapor pressure and heat transfer principles.

Engineered for Long-Term Stability

Efficient wet gas scrubbing is not defined by removal efficiency alone. Long-term performance depends on balanced liquid management, stable mass transfer conditions, and well-engineered purge and treatment concepts. By integrating these elements into a coherent system design, reliable emission control is achieved with minimized water consumption and predictable operating costs.