Inside Biodiesel Distillation: How We Reduce Sulfur, Lower Monoglycerides, and Improve Cold Flow

Introduction — The Chemistry Behind Clean, Stable Biodiesel

Trans‑esterified biodiesel can carry monoglycerides, moisture, color bodies, and trace sulfur each impacting performance and compliance. Distillation provides a robust thermal separation that refines FAME quality. When needed, adsorption polishing further reduces sulfur to <10 ppm, enhancing stability and compliance margins.

Distillation Mechanism — What We Remove and Why It Matters

Cutting Monoglycerides to Improve Cold Flow

Monoglycerides precipitate at lower temperatures and can impair CFPP. Distillation separates FAME from higher‑melting components, achieving monoglycerides ≤0.2 wt% and winter‑grade performance.

Moisture and Volatile Control

Biodiesel drying plus thermal separation keeps moisture <100 ppm, reducing hydrolysis risk and improving storage stability.

Color Improvement and Stability

Thermal fractionation also removes color‑forming components, improving appearance from yellow to near colorless.

Sulfur Reduction Pathways

Distillation for Acid‑Esterified and Pyrolysis Biofuel

These feeds can introduce sulfur species. Distillation reduces sulfur content, with typical <15 ppm results for distilled biodiesel.

Adsorption Polishing for ULSD Biodiesel

Adding adsorption downstream of distillation achieves guaranteed <10 ppm sulfur with:

• Common, affordable adsorbent

• No impact on distilled biodiesel properties

• Better color in the final biodiesel

• Typical processing cost: USD 28–33/ton treated distilled biodiesel

  
  

Performance Snapshot

• Monoglycerides: ≤ 0.2 wt%

• FFA: ≤ 0.25 wt%

• Moisture: <100 ppm

• CSFT: ≤ 300 s

• Sulfur: <15 ppm (distillation)

• Sulfur: <10 ppm guaranteed (with adsorption)

  
  

Process Integration that De‑Risks Operations

• Biodiesel‑Glycerin Separation, Biodiesel Washing, and Biodiesel‑Water Separation

• Methanol Recovery from biodiesel and glycerin (highest recovery rate and purity)

• Glycerin Drying and Glycerin‑Fatty Matter Separation

• Methanol‑Water‑Biodiesel Separation for acid esterification routes

• Fatty Acids Removal and Biodiesel/FAME Fractionation

• No rotating separation equipment → fewer moving parts, lower maintenance

• Post‑distillation candle evaporator to maximize FAME yield

  
  

Delivery Options and Execution

• Full ISBL, skid supply, or customizable scope

• Testing facilities available to validate feedstock, sulfur targets, and CFPP goals

• Guaranteed performance with a long reference list and reference plant in operation

FAQ

Q1: How does distillation improve CFPP?

A: By separating out heavier or higher‑melting components (e.g., monoglycerides) that cause crystallization at low temperatures.

Q2: What’s the difference between distillation alone and distillation plus adsorption?A: Distillation typically achieves <15 ppm sulfur; with adsorption polishing, sulfur is guaranteed <10 ppm.

Q3: Does the adsorption media affect FAME properties?

A: No. The add‑on does not impact the distilled biodiesel, and it improves color.

Q4: What about methanol handling?

A: We provide highest methanol recovery rate and highest purity recovered methanol from biodiesel and glycerin streams.

Q5: What equipment philosophy reduces maintenance?

A: Static separation no rotating separation equipment is required.

Q6: Can you tailor the scope?

A: Yes—ISBL, skid, or custom scope, backed by testing and guaranteed performance.

Have a challenging feed or sulfur target? Let’s engineer a distillation + adsorption train that meets your specs. Speak to an engineer