Biodiesel processor

A Biodiesel processor is a combination reaction vessel and still for producing biodiesel from vegetable oil.

Additional recommended knowledge

Daily Sensitivity Test

Essential Laboratory Skills Guide

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Industrial processors

Batch processing is convenient for small production volumes (no more than 10,000 t/year).

In the industrial continuous machines, the reaction and distillation of the alcohol is a batch processing and the decantation is continuous.

• In the static mixer, the esterification catalyst (most commonly sulphuric acid), the methanol and vegetable oil are mixed.
• In the reactor, esterification of free fatty acids occurs.
• In the second static mixer an alkaline catalyst (most commonly potassium hydroxide) is added to the methanol-oil mix for the transesterification.
• In the second reactor, transesterification occurs.
• In the third mixer, the product of the reaction (biodiesel, glycerol and methanol solvent) is neutralized by introducing a mineral acid.
• In the flash vaporizer (distillation unit), the alcohol is separated. The vapors of methanol are condensed and sent to the reception unit to be introduced again in the cycle.
• The remaining products in the flash vaporizer (biodiesel, glycerol, salts and water) are sent to the continuous decanter, to separate biodiesel from the rest of the by-products.
• The light phase of the solution in the decanter is sent to the storage tank and the heavy phase (impure glycerol and salts) is sent to another storage tank for later purification. It contains 80-90% pure glycerol, water and salts.
• Industrial scale purification of biodiesel and glycerin can be accomplished in high vacuum evaporators. A typical design is a "wiped-film evaporator" where the products are cleanly separated from the salts by both thermal and mechanical means.

Raw materials

These are the typical values of raw materials and consumables to produce 1,000 kg of biodiesel and 112 kg of glycerol (85% min.)

• Refined vegetable oil: 1030 kg.
• Methanol: 102 kg.
• Catalyst (sodium hydroxide or potassium hydroxide): 6.2 kg.
• Mineral acid: 6 kg

• SERVICES

• Cooling water: 20 m³
• Steam (at 400 kPa): 350 kg.
• Electricity: 50 kW·h.
• Nitrogen: 3.2 m³

Biodiesel processors for home brew users

Biodiesel can be made at home. The required ingredients are any triglyceride fat or oil (animal tallow or vegetable oil, as used in cooking), a strong base (for example sodium hydroxide (NaOH) or potassium hydroxide (KOH)), and relatively pure alcohol (either methanol or ethanol). Higher (longer carbon chain) alcohols, longer than isopropyl alcohol (commonly the main ingredient in rubbing alcohol), do not work so well. Used oil for processing is often obtained from restaurants.

A number of different variations on methods of making biodiesel exist. It is usually made in small batch processors in the garage but some have adapted processors to fit in the backs of vans and to be transportable.

One of the difficulties faced by potential biodiesel homebrewers is making a mid-scale biodiesel processor sufficiently simple to be cheap, safe, easy to make, appropriate and that produces biodiesel of sufficient quality for their requirements. Advice can be found on many biodiesel forums dedicated to users and producers of biodiesel.

See also

• Biodiesel production