The economics of used oil recycling increasingly depend on a refiner’s ability to turn recovered lubricant into a product that can compete in higher-value base oil markets. While distillation forms the backbone of many waste oil recycling plants, the final polishing stage can determine the color, odor, stability and overall commercial quality of the finished oil.

HERING VPT is addressing that stage with its AMPS Adsorbent Mineral Polishing System, a regenerative treatment designed for re-refined lubricant distillates.

The system uses the company’s PHÖNIX GREEN adsorbent mineral instead of conventional chemically activated bleaching clay. HERING says the material is naturally sourced and physically processed to develop a high surface area capable of adsorbing undesirable compounds from lubricant distillates.

More importantly for plant operators, the mineral can be regenerated within the system and reused repeatedly.

HERING states that PHÖNIX GREEN can remain in service for several hundred regeneration cycles, with a maximum of around 500 cycles cited for suitable applications. For re-refiners accustomed to purchasing, handling and disposing of large volumes of bleaching clay, that could substantially alter the operating-cost equation.

Why Re-Refined Oil Needs Polishing

Waste lubricating oil contains a complex mixture of base oils, additives, degradation products, sulfur-containing compounds, oxidation products and contaminants.

Vacuum distillation and evaporation can recover valuable lubricant fractions, but these processes do not necessarily remove every compound responsible for undesirable color, smell or instability.

That is where re-refined oil polishing becomes important.

The AMPS treatment passes the recovered oil through banks of columns containing the high-surface-area mineral. Polar and other unwanted compounds are adsorbed by the mineral, improving the characteristics of the finished oil.

According to HERING, the process can improve color and odor, remove oxidation-related contaminants and reduce sulfur content. The company reports sulfur reductions from around 2,000 ppm to less than 300 ppm in a single pass for appropriate feedstocks and operating conditions.

Multiple treatment passes can be used when further color improvement is needed.

These capabilities make the technology particularly relevant to refiners seeking to produce Group I base oil or preserve the characteristics of incoming Group II base oil.

Cutting the Cost of Disposable Clay

Traditional clay polishing systems remain attractive because of their relative simplicity and lower initial capital requirements compared with catalytic hydrofinishing.

Their disadvantage is waste.

Once bleaching clay becomes saturated with contaminants, it must be removed and replaced. Depending on local rules and the composition of the spent clay, treatment and disposal can create additional cost and environmental liabilities.

At the other end of the technology spectrum is hydrotreating, which can provide deep finishing but requires hydrogen, specialized reactors and operation at demanding process conditions.

For many medium-sized re-refineries, the investment required for a complete hydrotreating plant can be significant.

HERING’s proposition is to occupy the space between the two approaches.

The AMPS is marketed as an alternative to bleaching clay that avoids chemically activated adsorbents while also eliminating the need for hydrogen treatment in applications where adsorption can achieve the required oil specification.

Because the polishing medium is regenerated instead of discarded after each use, HERING says the system can reduce both consumable expenditure and waste generation.

From Small Processing Lines to Commercial Refineries

The AMPS platform is designed to cover a wide range of production requirements. HERING lists treatment capacities from 50 liters per hour to 27,000 liters per hour.

That makes the technology potentially applicable to smaller specialty processing operations as well as larger commercial waste oil re-refining plants.

The equipment can be installed behind vacuum distillation or wiped-film evaporation equipment as a final polishing unit. HERING also offers the technology as part of its WORP waste oil recycling system.

For existing refiners, retrofit potential may be particularly attractive. Plants operating legacy acid-clay or bleaching-clay finishing stages may be able to introduce regenerative mineral polishing without replacing the entire upstream process.

A Circular-Economy Opportunity

Used lubricating oil represents both an environmental challenge and a valuable hydrocarbon resource.

Recovering the base oil fraction reduces the need to treat used lubricant purely as waste and can return valuable material to the lubricant supply chain. However, the business case for lube oil re-refining becomes stronger when recycled output can meet higher commercial standards.

This is why polishing technology matters.

A finishing system that delivers cleaner appearance, reduced odor and improved chemical stability can potentially turn a relatively low-value distillate into a more marketable re-refined lubricant base oil.

HERING’s AMPS technology combines this quality-upgrading role with a regenerative adsorbent intended to reduce reliance on disposable clay.

While plant operators will still need to assess feedstock variability, product specifications, local disposal rules and lifecycle operating costs, the technology illustrates a broader trend in lubricant recycling: extracting greater value from used oil while reducing the environmental burden of the refining process itself.

For re-refiners seeking a lower-waste base oil finishing system, regenerative adsorbent mineral technology is emerging as an option worth evaluating alongside conventional clay polishing and hydrogen-based finishing.