Welcome to Imerys Performance Minerals

Biodiesel Filtration

Biodiesel Filtration

1. A perlite filter solution for improved cold soak in biodiesel production

Imerys is leading the way to facilitate more throughput from filtration absorbents in biodiesel production to help producers meet high market demand and environmental policies to use more waste-based feedstocks.

The challenge

While traditional filtration methods tend to work, any impurities that carry over can cause the batches to fail testing standards from sterol glucosides (SG) remaining in solution. Sterol Glucosides (SG), even at low concentration, catalyze the formation of waxy particles in the biodiesel, increasing cold soak times.

The solution: Harborlite 900S-SG

Replacing existing biodiesel filtration systems with one using Harborlite™ 900S-SG (perlite) as a drop-in filter aid can significantly enhance the quality results of biodiesel with superior SG removal where other means fail or when temperatures are not conducive to bring SG impurities out of solution.


Biodiesel plants using soy or canola oil feedstocks to make biodiesel can benefit from using Harborlite 900S-SG by enabling the cold soak process to be held at higher temperatures versus conventional filter aids (up to 20o Fahrenheit with similar SG removal in tests). The reduction in chilling temperatures can help to save on energy costs and reduce times in the chilling process leading to higher throughput where chill times are a constraint. In the process where there is no cold soak chilling step, flexibility is added by allowing removal of sterol glucosides at much higher temperatures during summer months than conventional means with filter aids leading to higher first pass quality and reduces need for blending off.

Features and Benefits

  • Forms a thick permeable filter cake
  • Low bulk density
  • High void volume and porosity
  • Relatively inert in most solvents
  • Neutral pH
  • Hydrophilic
  • Low crystalline silica

2. A two-in-one diatomite based solution for biodiesel refining

Imerys has developed a surface-engineered diatomite to replace silica gels and magnesium silicates in biodiesel refining, simplifying the process and reducing spent filter cake and oil loss.

The issue

Previously used edible oils, cooking oils and recycled animal fats are used for the production of biodiesel and oleochemicals and often contain soaps/phospholipids, glycerol and trace metals that need to be removed as part of the refining process. Typically, this is done during a filtration stage via the addition of a synthetic amorphous silica gel or a magnesium silicate. These products have excellent adsorption characteristics but are poor filter aids causing premature filter blockage and reduced refining capacity. Often, a diatomite filter aid is added to compensate and to keep the filter bed ‘open’. While this achieves the required increase in filtration capacity, it also adds process complexity and results in additional spent filter cake and associated oil loss.

The solution: CynerSorb®

Imerys CynerSorb® has been developed as a two-in-one solution to replace silica gels and magnesium silicates in the refining process. 

CynerSorb® utilizes a diatomite filter aid ‘base’ meaning it has all the filtration characteristics of a diatomite. However, our engineers have successfully surface-engineered the individual diatomite particles so they also provide the necessary adsorption functionality. As a result, CynerSorb® can be used as a two-in-one solution fulfilling both the absorption and filtration functions.

CynerSorb® can also be used to eliminate bleaching earth where no color removal is required, or to significantly reduce dosing rates where some bleaching is necessary.

Application specific benefits

  • Excellent filtration characteristics: allows reduction/removal of current filter aid and increases production capacity
  • More effective at breaking down soaps, phospholipids, trace metals and polar contaminants than current solutions
  • Works synergistically with bleaching earth: allows significant reduction of bleaching earth addition
  • Reduces oil loss
  • Can be used with a number of feedstocks, including used cooking oil (UCO), refined vegetable oil or animal fat/tallow.
  • Are as versatile as pretreatment of feedstock material to reduce impurities, or post treatment to replace current adsorption solution.

We offer a full range of custom formulation and technical and process support services to help you match the right mineral grade to your application requirement.

Please contact us, we will be only too happy to help.

Contact us Contact

Energy & Environment