Process Configurations

Chapter from the Renewable Fuels Processing Guide.

PROCESS CONFIGURATIONS

Configuration Comparison

Configuration	Description	Feed Blend Limit	Capital Cost	CI Benefit	Advantages	Limitations
Co-processing in existing HDT	Blend renewable feed into existing hydroprocessor	5-20% (typical limit)	Very low (existing unit)	Proportional to blend	Minimal capital, quick implementation	Limited blend rate, certification challenges
Standalone HVO unit	Dedicated unit for 100% renewable feed	100%	High (new unit)	Full CI credit	Maximum flexibility, full product credit	Higher capital, feedstock logistics
Converted refinery unit	Repurpose existing hydrotreater/HCK for renewables	100%	Medium (modifications)	Full CI credit	Leverages existing equipment	May need metallurgy upgrades, H2 capacity
Two-stage (HDT + isomerization)	First stage: HDO/DCO; second stage: isomerization	100%	Highest	Full CI + better cold flow	Best product quality, SAF capable	Most complex, highest H2 consumption

Co-Processing Considerations

Co-processing renewable feedstocks in existing hydroprocessing units is the fastest path to production but has important limitations:

Blend Rate Limits:
• 5-10%: generally no equipment modifications needed
• 10-20%: may need metallurgy review (water formation → corrosion)
• >20%: likely needs dedicated reactor, H2 system modifications

Equipment Impacts:
• WATER: HDO produces ~10-15 wt% water from triglycerides — must be managed
- Sour water system may need expansion
- Reactor internals exposed to acidic water at temperature
- Separator boot capacity may be insufficient
• H2 CONSUMPTION: 2-3× higher than petroleum hydrotreating per barrel
- H2 plant or PSA capacity may limit blend rate
• CO/CO2: decarboxylation produces CO and CO2
- CO inhibits HDS catalyst temporarily
- CO2 can form carbonic acid with water
- Recycle gas purity affected
• HEAT: renewable reactions are more exothermic than petroleum HDS
- Quench capacity may limit feed rate
- Monitor reactor ΔT carefully when increasing blend

Source: Renewable_Fuels_Processing_Guide_v1.xlsx · sheet “Process Configurations”

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