Technology Highlights
Sequoia’s Expertise for Hydrogenation Projects:
Hydrogenation is a chemical reaction of hydrogen with hydrocarbons (like oil), sulfur, nitrogen, chlorine compounds among other things. It requires specific conditions of pressure and temperature depending on the reaction. In the context of rerefining, hydrogenation is commonly referred to as Hydrotreating. It helps remove from oil sulfur, chlorine and nitrogen compounds. Further, hydrogen saturates , and upgrades the oil to meet higher quality standards—such as American Petroleum Institute’s (API) Group II or Group III base oil specifications.
Sequoia delivers hydrogenation systems with a focus on reliability, customization, and long term support. Our approach includes:
- Flexible Scope of Work: We are experts at design of hydrotreating plants. However, we can supply the equipment, the steel structures, and also piping materials, instruments, and controls—under a single lump-sum contract.
- Safety & Metallurgy: We follow proven and accepted industry standards for material selection and safety systems necessary for hydrogen applications.
- Trusted Partnerships: We work with vendors who have proven experience in hydrogenation technology.
- Tailored Design: Every plant is custom-engineered to match given feedstock and performance goals.
- Modularization: Wherever feasible, we design modules to simplify installation and reduce site work.
- Ongoing Support: Our team remains actively involved in operations for 10+ years after commissioning of a plant.
Hydrogenation Process Overview:
The diagram illustrates Sequoia’s hydrogenation system for upgrading lube oil base stocks and vacuum gas oils into Group II+ and Group III base oils. This process involves several key stages:
Process Flow:
- Feed Preparation: Incoming feedstock, fuel, and make-up hydrogen are filtered and pressurized.
- Heating & Reaction: The oil is heated and mixed with hydrogen rich gas. The heated mixture flows into a high pressure reactor, where hydrogenation reactions occur removing sulfur and nitrogen, and saturating olefins and aromatics.
- Separation & Cooling: The gas and oil mixture exiting the reactor is flashed to separate the vapor and liquid phases. The liquid is depressurized. Light hydrocarbons are separated, while the remaining product is cooled. The flash vapors are cooled and compressed for recycle back to the reactors.
- Final Separation: A separator and column fractionate the hydrogenated base oil into distinct viscosity grades of base oil.
- Output Streams: The system yields:
• Hydrotreated fuel
• 3-4 base oil fractions.
• Byproducts such as wastewater and purge gases
- Key Equipment:
• Filter, Pump, Heater, Reactor
• Compressor, Cooler, Separator, Column
Sequoia has designed hydrogenation plants for capacities ranging from 500 to 5,000 barrels/day, with proven reliability and long-term operational support.
- Hydrogenation of Bio-Feedstock / Renewable Diesel (HDRD):
Sequoia offers hydrogenation systems for producing high-quality renewable diesel from a wide range of bio-based feedstocks. Unlike traditional biodiesel, which is produced via trans-esterification and results in oxygenated fuel and glycerol byproducts, HDRD is a cleaner, more compatible alternative to traditional diesel. - Limitations of Traditional Biodiesel:
Traditional biodiesel is produced via transesterification using methanol, which creates an oxygenated fuel diesel that cannot be blended with fossil-fuel diesel. This process generates glycerol as a byproduct, and the of free fatty acids (FFAs) in the feedstock leads to soap formation, which complicates processing and reduces yield. - Why HDRD? OR Advantages HDRD:
A cleaner, compatible alternative Hydrogenation Derived Renewable Diesel (HDRD) is produced by reacting oxygenated fatty compounds (triglycerides) with hydrogen. This process removes oxygen from the biofuel and converts the feedstock into saturated straight-chain hydrocarbons of the diesel boiling range. The byproducts—water, propane, carbon monoxide (CO), and carbon dioxide (CO₂)—are clean and manageable. Importantly, soap formation from FFAs is not an issue in this process. - Drop-In Renewable Diesel Fuel:
The result is a “drop-in” renewable diesel that meets international fuel standards such as ASTM D975 and ISO specifications. This fuel is chemically similar to fossil diesel, allowing it to be blended, transported, and used interchangeably in existing engines and infrastructure. In the USA, HDRD qualifies for higher renewable fuel credits than conventional biodiesel, offering both environmental and economic advantages. - Wide Feedstock Flexibility:
HDRD can be produced from a broad range of bio-based feedstocks, including:• Vegetable oils
• Animal fats
• Lignocellulosic biomass from agricultural residues and pulp and paper wasteThis flexibility makes HDRD production more scalable and sustainable than traditional biodiesel, which is limited to specific feedstock types. - Sequoia’s Hydrogenation Systems:
We design all equipment required for the hydrogenation of bio-feedstocks to produce HDRD. Our systems are custom-engineered to match feedstock type, processing capacity, and product quality targets—ensuring efficient, reliable, and standards-compliant renewable diesel production. - Sequoia’s Hydrogenation Technology for ULSD :
Sequoia designs advanced hydrogenation systems to enhance oil quality. Our process focuses on sulfur removal and aromatic saturation, ensuring compliance with fuel standards.
Key Objectives:
• Sulfur Reduction: The primary goal is to remove sulfur from base oils and vacuum gas oils, ensuring compliance with environmental regulations.
• Aromatic Saturation: Saturating aromatic compounds is essential to produce Ultra Low Sulfur Diesel (ULSD) that meets the latest ASTM and global specifications. Our systems are engineered for reliability, safety, and long-term performance—tailored to feedstock and capacity requirements. - Hydrogenation of Naphthenic and Waste Transformer Oils:
Sequoia delivers advanced hydrogenation systems for the re-refining and recycling of waste transformer oils, even those based on naphthenic base oil chemistry. When combined with vacuum drying and multi-stage filtration, hydrogenation becomes the most complete and effective process for restoring spent transformer oils to high-performance standards for new transformer oils. - Process Highlights:
During hydrogenation, hydrogen gas reacts with sulfur, nitrogen, chlorine including the PCBs (polychlorobiphenyl compounds), and unsaturated compounds found in aged or contaminated transformer oils. This chemical conversion produces a water-white, stable base oil with:
• Low sulfur content
• Superior dielectric strength
• Improved oxidation resistance
• Enhanced thermal stability and no toxicity - Preservation of Naphthenic Oil Properties:
Our technology is engineered to retain the beneficial characteristics of naphthenic oils, such as low pour point and high solvency, while selectively removing degraded compounds and impurities. This ensures the recycled oil performs reliably in demanding electrical applications. - Destruction of Harmful Contaminants
Our hydrogenation systems are capable of nearly complete destruction of carcinogenic organic chlorine compounds, including PCBs (Polychlorinated Biphenyls), which are commonly present in waste transformer oils. This makes the process environmentally responsible. - Output Quality & Global Standards
The resulting re-refined transformer base oils meet or exceed OEM specifications across major global markets in the USA, Europe and Japan Sequoia’s hydrogenation systems support sustainable oil recovery, hazardous waste reduction, and cost-effective transformer oil regeneration for utilities, refineries, and industrial oil processors.
Utility Costs
Electricity, fuel, water, chemicals, and wastewater treatment by
mechanical vapor compression typically cost between $15–30 per cubic meter of
processed used oil—that’s around ~$0.06–0.13 per US gallon.
Manpower Requirements
A fully integrated waste oil regeneration facility
operates smoothly with a team of 10 to 15 people.
Land Requirement
Depending on plant capacity, it requires 1 to 7 acres (roughly
4000 to 28000 square meters) to accommodate all core units—distillation,
hydrotreating, adsorption, and support infrastructure.
Operational Economics of Re-Refining Technology
Setting up and operating a used oil re-refining plant comes with certain essential cost and resource considerations.
Based on what we have implemented