Packed Bed Scrubber
Envitech's high-efficiency, low pressure drop packed bed scrubbers use random or structured packing, a mist eliminator, and a liquid distribution system to remove acid and toxic gases through a process of absorption and neutralization. The packed media provides mass transfer area to absorb acid gases such as SO2, HCl, NH3, and other gases.
Packed bed scrubbers contact a liquid, typically water, with a gas to transfer a component of the gas into the liquid. Typically, gas flows upward through the packed bed, and liquid flows downward. The liquid contacts the gas, and the contact area is enhanced by the use of packing, which disperses the liquid and the gas, providing more contact area to transfer the targeted component into the liquid.
The performance of a packed bed scrubber depends on many factors, but mostly importantly the driving force of the gas component into the liquid and the performance of the mass transfer media.
There are several ways to improve the driving force of the targeted component into the liquid. The temperature can be cooled or the gas can be compressed to favor liquid absorption. The qualities of the liquid such as the pH, oxidation potential, or chemical enhancers can improve the liquid's capacity for absorption. Or, the targeted component can undergo a reaction, in either the gas or the liquid, that improves its absorption.
Similarly, there are multiple ways to improve mass transfer, although some are at odds with increasing the driving force. Modifying the qualities of the gas and liquid, by increasing its temperature, wettability, or diffusivity improves mass transfer. However, more commonly, the type of mass transfer media and the volume of mass transfer media are used to manipulate its performance. Increasing the volume of the mass transfer media increases the contact time of the liquid with the gas, increasing the time for the component to transfer from the gas to the liquid. Alternately, using mass transfer media that creates greater contact, usually at the cost of pressure drop, can improve performance.
Envitech packed bed scrubbers have been used in over 100 applications including waste incinerators, thermal oxidizers, furnaces, kilns, roasters, boilers, exhausts, reactors, and digesters. Standard models are fabricated from high-strength, corrosion-resistant, fiber-reinforced plastic (FRP) in accordance with the latest ASTM and product standards. Other materials of construction such as stainless steel are available upon request.
Envitech's typical systems include all packed bed scrubber internals, re-circulation pumps, instrumentation, chemical feed pumps, chemical storage tanks, and a control system. Models within a certain size range can be shipped with a rectangular footprint fully integrated to minimize on-site installation costs.