Hydrogenated Fats Diesel (HFD), also known as Renewable Diesel (RD) or Hydrotreated Vegetable Oil (HVO), is a paraffinic hydrocarbon fuel produced by hydrotreating triglyceride-based feedstocks under high temperature and hydrogen pressure. Unlike conventional biodiesel (FAME), HFD is chemically almost identical to fossil diesel, consisting mainly of straight-chain and branched alkanes (C15–C18). This makes it a true drop-in diesel fuel suitable for all compression-ignition engines and existing fuel infrastructure.
Feedstocks Used in HFD Production
HFD production is flexible and can utilize a wide range of renewable and waste-based oils:
Primary Feedstocks
Used Cooking Oil (UCO)
Animal fats (tallow, lard, poultry fat)
Fish oil residues
Vegetable oils (soybean, palm, rapeseed, sunflower)
Distillers corn oil (DCO)
Advanced & Waste Feedstocks
Brown grease
Acid oils
Sludge oils
Palm Fatty Acid Distillate (PFAD)
Higher waste feedstock usage = lower lifecycle carbon intensity (CI).
Manufacturing Process (Hydrotreating Technology)
Step-by-Step Process
1.Pre-treatment:
Removal of water, metals, phospholipids, and impurities
2.Hydrogenation
Saturation of double bonds
Removal of oxygen via:
Hydrodeoxygenation (HDO)
Decarboxylation (DCO₂)
Decarbonylation (DCO)
3.Isomerization:
Improves cold flow properties by branching paraffins
4.Fractionation
Separation into:
Renewable diesel (HFD)
Renewable naphtha
Renewable LPG
Key Difference from Biodiesel (FAME)
| Aspect | HFD | Biodiesel (FAME) |
|---|---|---|
| Oxygen Content | 0% | ~10–11% |
| Stability | Very high | Moderate |
| Cold Weather Performance | Excellent | Poor |
| Blending Limit | 100% | Typically ≤20% |
| Engine Compatibility | Full | Limited |
Chemical & Combustion Characteristics
Fuel Chemistry
Paraffinic hydrocarbons
No aromatics
No oxygen
No sulfur
No metals
Combustion Advantages
Higher combustion efficiency
Shorter ignition delay
Lower peak combustion temperatures
Reduced engine deposits
Extended engine oil life
Environmental & Lifecycle Benefits
Greenhouse Gas Reduction
60–90% CO₂ reduction vs fossil diesel (well-to-wheel)
Carbon intensity depends on:
Feedstock type
Hydrogen source
Process efficiency
Emission Reductions
Particulate Matter (PM): ↓ up to 40%
NOₓ: ↓ 10–30%
Carbon Monoxide (CO): ↓ 20–50%
Unburned hydrocarbons: significantly reduced
Sustainability Certifications
ISCC (EU / Plus)
RED II / RED III compliant
RSB certified
CORSIA eligible (when upgraded to SAF)
Fuel Standards & Specifications
HFD complies with global diesel fuel standards:
EN 15940 (Europe – paraffinic diesel)
ASTM D975 (USA – renewable diesel)
ASTM D396 (Heating oil)
ISO 8217 (Marine fuels – select grades)
Fully compatible with pipelines, storage tanks, and dispensing systems.
Storage, Handling & Shelf Life
Storage Characteristics
Non-hygroscopic (does not absorb water)
High oxidation stability (>12 months)
Resistant to microbial growth
Lower risk of filter plugging
Handling
Can be blended on-site or at terminal
Compatible with existing diesel logistics
No special materials required
Performance in Engines
Engine Benefits
Improved cold starts
Reduced knocking
Lower exhaust opacity
Cleaner injectors and combustion chambers
Compatibility
Light-duty diesel vehicles
Heavy trucks
Construction equipment
Agricultural machinery
Marine diesel engines
Stationary power generators
Industrial & Commercial Applications (Expanded)
1. Transportation
Trucks & buses
Rail locomotives
Mining & quarry vehicles
Logistics fleets
2. Power Generation
Diesel generator sets
Remote off-grid power plants
Backup power systems
3. Industrial Use
Boilers
Furnaces
Process heaters
Cement and steel plants (pilot substitution)
4. Marine Sector
Inland waterway vessels
Harbor craft
Low-sulfur marine diesel blending
5. Aviation Pathway
HFD serves as a primary feedstock for:
HEFA-SPK Sustainable Aviation Fuel
Up to 50% blending with Jet A-1 (ASTM D7566)
Market Positioning & Economics
Advantages Over Fossil Diesel
Stable pricing vs crude volatility
Regulatory incentives & carbon credits
ESG compliance
Corporate decarbonization goals
Key Market Drivers
Net-zero commitments
Fuel blending mandates
Carbon taxation
Corporate sustainability reporting
Limitations & Considerations
Higher cost than fossil diesel (without incentives)
Feedstock availability constraints
Hydrogen sourcing impacts carbon intensity
Cold flow properties vary by region & grade