Regenerative thermal oxidizers (RTO) are widely employed by chemical, petrochemical and pharmaceutical plants to effectively destroy volatile organic compounds (VOCs) and harmful air pollutants. Most RTO systems utilize Christy Fill honeycombs or T-99 ceramic media beds to capture waste heat generated by combustion while preheating combustion air for efficiency.

RTO stands for Reversible Thermal Oxidation process, and involves the reversible separation of phenols and cresols using fractional distillation. In the past, these chemicals were separated through batch distillation using tall columns which consumed both time and energy to operate. To increase yield and purity of his products, Dr. Fritz Raschig sought an efficient method of dividing them. His initial attempt involved filling a distillation column with wine bottlenecks; however these proved problematic with column performance due to shattering glass necks shattering throughout.

Raschig rings have quickly become one of the most widely-used random packing materials for distillation. These tubular pieces shaped like saddles with ridged surfaces provide additional surface area for mixing and interaction between condensed material and vapor, creating moderate amounts of theoretical plates while having low hold-up pressure loss, making these rings ideal for distilling viscous materials without flooding issues or clogging issues.

The present invention concerns a regenerative thermal oxidizer system comprising three separate heat transfer columns 16, 18 and 20 that are in fluid flow communication with a combustion chamber 12. A contaminated vapor stream first passes through the first column where it undergoes preheating through heat exchange with hot combusted steam before being diverted to the second one for cooling by heat exchange with hot combusted steam from column one.

Raschig rings are an extremely popular packing material used for moonshine still distillation, due to their porous ceramic composition and ability to allow vapors to pass freely across large surface areas without becoming trapped and choked off in any given section of your column. Furthermore, their inert nature means they should last forever so long as you keep them clean!

Cleaning these types of packing materials typically involves using highly caustic and corrosive cleaners that leave behind deposits on their inner surfaces that are difficult to eradicate, often damaging the material even after severe treatment such as heating the packing in a torch or other device.

This invention describes a novel approach for the removal of deposits on ceramic Raschig rings. This technique employs large volumes of wetted sand that has been saturated with cleaning solution to be tumbled with, thus greatly shortening contact time between cleaning solution and ring and the latter, therefore significantly lessening corrosion damage compared to alternative techniques used previously.

This method can be performed using any mixer or tumbler capable of providing controlled tumbling action. In general, the amount of sand employed should correspond to the number of raschig rings to be cleaned; for instance, in an Essential Extractor Pro Series II High Capacity/Volume column you would require 1.5 L of sand per row of ceramic raschig rings being processed.

Raschig rings for water aeration can help prevent the development of harmful algal blooms, according to this article from Kasco Marine. Aeration increases surface area available for gas exchange and can reduce oxygen requirements; however, depending on how and where an aerator is installed this system may or may not work as effectively.

Raschig rings are commonly employed in chemical separation and mass transfer processes like fractional distillation. Their large surface area for liquid-vapor interaction outshines other packing types and outperforms fractal patterns; plus they’re relatively inexpensive and customizable with different materials and wall thicknesses to meet various applications.

Rings also boast the added advantage of being resistant to radioactive leakage than other packing materials, especially if made of materials with high radioactivity levels or chemical sensitivities such as glass. Plus, they can be fitted with leak detection devices to warn operators when concentrations of radioactive material exceed safe limits.

Raschig rings are tubular pieces of roughly equal length and diameter that serve as tower packing in chemical processing and mass transfer applications, including fractional distillation. Also referred to as adsorption columns or random packing, Raschig rings were introduced by Friedrich Raschig in 1907 with Pall rings being an iteration on these early early designs.