A lube oil polishing system is the critical final stage in the production of premium re-refined base oils. In re-refining operations, even after advanced dehydration, thin-film or non-cracking evaporation, the resulting lube distillates—though largely free of heavy contaminants—still contain trace levels of sulfurized and oxidized compounds, color bodies, odorants, and unstable polar species. These impurities degrade the oil’s appearance, odor, and long-term oxidation stability, preventing it from meeting stringent specifications for Group I or Group II base stocks. A lube oil polishing system ensures these contaminants are removed, delivering market-ready oils that meet the performance, stability, and appearance standards required by industrial blenders and OEMs.

Hering VPT’s AMPS® (Adsorbent Mineral Polishing System) is a next-generation industrial oil polishing system designed to dramatically enhance oil quality without the drawbacks of traditional methods. Using PHÖNIX GREEN—an advanced physically enhanced mineral adsorbent—the system delivers water-white oils (often Saybolt +16 or better), eliminates detectable odors, cuts sulfur content from around 2,000 ppm to less than 300 ppm in a single pass, and stabilizes the oil against oxidation. Unlike acid-activated bleaching clays or costly hydrogenation, AMPS achieves this without generating hazardous waste, making it a sustainable and cost-efficient choice for both small and medium-sized plants. As a piece of base oil polishing equipment, AMPS integrates seamlessly into new re-refining lines or as an upgrade to existing facilities, with capacities ranging from 50 L/h pilot units to ~27,000 L/h industrial-scale systems.

What Makes a Lube Oil Polishing System Essential

A lube oil polishing system is not simply a quality booster—it is a market enabler. Without this final polishing stage, base oil streams risk falling short on key metrics such as color, odor, sulfur content, and oxidation stability. In practice, there are two main polishing approaches: hydrofinishing and adsorption-based polishing. Hydrofinishing uses high-pressure hydrogen and catalysts to remove residual contaminants and saturate molecules, delivering excellent results but at the cost of high capital expenditure, complex safety requirements, and intensive operating conditions. In contrast, adsorption-based polishing passes the oil through columns filled with reactive media that selectively remove impurities. Traditional acid-activated clays, while lower in capex, generate large volumes of hazardous waste and face increasing regulatory restrictions.

The AMPS® industrial oil polishing system eliminates these issues by using PHÖNIX GREEN mineral media. This media is physically enhanced—not chemically activated—making it reusable for up to 500 cycles before disposal, with end-of-life classification as standard industrial waste. It offers the same or better product quality compared to clay-based systems, without hazardous waste streams, aligning with both economic and environmental objectives.

How the AMPS Lube Oil Polishing System Works

The AMPS lube oil polishing system operates as a back-end process after distillation or thin-film evaporation. Feed oils such as 150N or 220SN are conditioned to optimal temperature and viscosity before entering the adsorption columns. Depending on production goals, operators can run in parallel mode for maximum throughput or in series mode for the highest color and odor refinement. Inside the columns, PHÖNIX GREEN selectively adsorbs polar molecules, residual sulfur and oxidation products, and other compounds responsible for odor and color degradation. Because it is an adsorption—not cracking—process, the oil’s viscosity index remains intact, ensuring that a Group II feedstock emerges as an enhanced Group II product.

Once adsorption capacity is reached, the columns are thermally regenerated in place. This reactivation process restores the PHÖNIX GREEN’s adsorption capability for hundreds of cycles, sharply reducing consumable costs. When the media reaches end-of-life, it can be directly disposed of in a landfill without special treatment, eliminating complex waste-handling requirements.

Measurable Improvements in Oil Quality

The AMPS lube oil polishing system achieves significant improvements in key quality metrics. It delivers water-white clarity (Saybolt +16 or higher), eliminating the “re-refined” visual signature that can limit market acceptance. Odor is reduced to non-detectable or barely detectable levels, essential for premium packaging oils and sensitive applications. Sulfur content is reduced by more than 85%, typically from around 2,000 ppm to below 300 ppm, meeting blending and emissions requirements. Oxidation stability is greatly enhanced by removing reactive polar species, extending shelf life and improving in-service performance. Importantly, these results are achieved without any loss of viscosity index.

Why Choose AMPS Over Hydrofinishing

While hydrofinishing remains the gold standard for deep chemical modification of oil molecules, its complexity, cost, and hydrogen-handling requirements make it impractical for many re-refiners. The AMPS industrial oil polishing system delivers comparable results in color, odor, sulfur, and stability for Group I/II base oils, but with far lower capex, simpler operations, and no need for high-pressure hydrogen. Its landfill-disposable media also provides a clear environmental advantage.

Impact on Plant Efficiency and Operating Costs

In addition to improving oil quality, the AMPS lube oil polishing system improves plant efficiency. Its long-life media sharply reduces consumables costs and handling labor. Modular column banks allow for continuous operation during media regeneration, maximizing uptime. The system’s waste stream is non-hazardous, minimizing disposal costs and environmental compliance burdens. Higher product quality protects market value, reducing off-spec rework and expanding sales channels. With containerized, globally compatible modular designs, AMPS installations are straightforward and scalable.

Industrial Applications for Base Oil Polishing Equipment

The AMPS base oil polishing equipment serves a wide range of applications. In smaller-scale operations, it can convert distillates from in-house re-refining into high-quality oils for internal use or local sale. Regional re-refiners use it to enhance color and odor, reducing reliance on bright stock and widening blending options. Large-scale national re-refiners integrate it into full WORP® lines to finish multiple base oil grades for broad distribution. The system’s ability to handle mixed feedstocks and maintain high yields—often 70–80% from used oil feed—underscores its operational flexibility and contribution to circular economy goals.

Technical and Environmental Advantages

Technically, AMPS targets polar species, odorants, sulfurized and oxidized compounds, and color bodies, delivering oils that meet premium specifications. Throughput options range from 50 L/h to 27,000 L/h, with flexible parallel or series operation. PHÖNIX GREEN media is physically enhanced, reusable up to 500 cycles, and landfill-safe. Environmentally, the system minimizes waste generation, supports energy recovery in integrated plants, and dramatically reduces crude oil displacement—re-refining just 4 liters of used oil can replace the 160 liters of crude needed to produce the same amount of lubricating oil from virgin sources.

Supporting Blenders and End-Users

For blenders, the consistency and stability of AMPS-polished oils mean more predictable formulations, stable additive treat rates, and improved acceptance of re-refined stocks in high-value markets. For end-users, the benefits are oils with better appearance, longer shelf life, reduced sulfur, and superior oxidation stability—all without compromising viscosity index.

The Business Case for AMPS

For operators weighing traditional acid-clay systems, hydrofinishing, or modern adsorption technologies, the AMPS lube oil polishing system offers a compelling balance of performance, cost, and environmental responsibility. It provides premium oil quality without hydrogenation, uses reactivable media with long service life, avoids hazardous waste, and can be deployed at scales from pilot plants to large industrial facilities. By enabling high-quality base oils from re-refined feedstocks, AMPS strengthens profitability, regulatory compliance, and sustainability.