Distillation Columns for Glycerol Treatment

Distillation Columns for Glycerol Treatment

In biodiesel production, glycerol (or glycerin) is a primary by-product of the transesterification process. However, the glycerol obtained directly from this process isn’t pure; it contains impurities like methanol, water, catalyst residues, and soaps. To make this glycerol a valuable co-product, it needs to be refined and purified. Distillation columns play a pivotal role in this purification process.

The Role of Distillation in Glycerol Treatment

  • Methanol Recovery: One of the most crucial steps in glycerol refining is the removal of excess methanol. This is achieved by utilizing a distillation column since methanol has a lower boiling point than glycerol. Recovered methanol can be reused in the biodiesel production process.
  • Water Removal: Water is another contaminant in raw glycerol. Through distillation, water is separated due to its different boiling point.
  • Purification: High-grade glycerol, suitable for pharmaceutical, cosmetic, or food applications, requires further purification. Distillation columns help in achieving the required purity by separating glycerol from other impurities based on their boiling points.

Types of Distillation Columns Used in Glycerol Treatment

  • Batch Distillation Columns: Operate in batches and are especially useful for small-scale operations or where product specifications change frequently.
  • Continuous Distillation Columns: Suitable for large-scale, continuous operations. They offer consistent outputs and are more energy-efficient for high-volume operations.
  • Fractionating Columns: These columns have multiple trays or packing, allowing for the separation of various components in a single column based on their boiling point differences.

Factors to Consider for Distillation of Glycerol

  • Feed Composition: The initial concentration of impurities in the glycerol affects the distillation process. A higher concentration of volatile components like methanol might require more energy for separation.
  • Desired Purity: Glycerol for industrial use might not need as rigorous purification as glycerol for pharmaceutical or food applications. The desired purity level influences the distillation process and the type of column used.
  • Energy Consumption: Distillation is energy-intensive. Optimizing column operations and integrating heat exchangers can enhance energy efficiency.
  • Equipment Material: Glycerol and its contaminants can be corrosive. Hence, distillation equipment should be made of materials resistant to corrosion, like stainless steel.

Advantages of Distillation in Glycerol Treatment

  • Value Addition: Purified glycerol fetches a higher market price compared to crude glycerol.
  • Sustainability: Recovering and recycling methanol makes the biodiesel production process more sustainable and cost-effective.
  • Versatility: Distillation offers the flexibility to treat glycerol with varying levels of impurities and achieve desired purity levels.


Distillation columns are vital for transforming crude glycerol, a by-product of biodiesel production, into a high-value product. Through effective distillation, impurities are separated, making glycerol suitable for various applications, from industrial to pharmaceutical. Ensuring an optimized and efficient distillation process is crucial for maximizing the profitability and sustainability of biodiesel operations.