Processor - with methanol condenser (GL design)

This page is Work In Progress and therefore may not be complete.

Graham Laming with GL processor. Source GL

The GL Processor is a design by Graham Laming (hence the GL) and has probably become most popular processor design for homebrew biodiesel production in the UK. The processor features built in dewatering and Methanol recovery capabilities, as well as protection against user exposure to Methanol vapour. The design also lends itself to a variety of production techniques.

Basic design

The design has been in existence for many years. It has been supplemented and improved by various users during this time. Below is a schematic of Graham’s basic design (with sight glass added) along with instructions on its use. Reproduced with kind permission from Graham. Although the design has been modified by others, Graham’s basic design is capable producing high quality Biodiesel and due to its simplicity of design is suitable for those new to home production.

This is a compact home made biodiesel processor which avoids water-washing and limits methanol release to very small amounts. You can also recover surplus Methanol from your biodiesel, which would otherwise be lost in the wash water.

You can de-water your oil in the processor and you can start to recover methanol from as low as 40 degrees C.

Here's a diagram of the system. It includes a simple venturi to recirculate vapour through a condenser. The venturi also sucks methoxide (or water, if you do the 5% prewash) from the methoxide container and mixes it into the oil flow.

Allow a straight horizontal run of around 30cm after the venturi outlet to ensure the venturi will perform properly. This is because the momentum of the out-flowing liquid acts to "pull" on the inlet vapour.

You can mount the Methoxide tank up, nearer the venturi, if your venturi's performance is marginal. Make sure it is not too high - you don't want to drop the container, spill the methoxide, or hurt your back.

State diagram for the Basic GL processor

State diagram: Green = open valve, or power applied
Step	Heater	Pump	V11	V2	V3	V4	V5	V6	V7	Notes
Oil in										Pre-filtered
Heat Oil	50C									Check level before applying heat
Dewater oil	90C									Switch to 50C when O/P slows
Cool oil	50C									Titrate oil now. Empty collector. I use NaOH
Inject Methoxide						Adj.				Allow 20 mins to inject.
Reaction Stage										Allow 90 mins at 50C
5% Prewash										Mix 15 mins
Settle Glycerol										Wait 90 mins
Drain Glycerol										Drain slowly to avoid whirlpool
Distil methanol	90C
Drain Biodiesel	off						Adj.			Ensure heater is OFF first! Caution - Hot! Wear breathing apparatus. Take sample and perform 23/7 test before discharging whole batch.

Step	Heater	Pump	V1	V2	V3	V4	V5	V6	V7	Notes
Oil in										Pre-filtered
Heat Oil	50°C									Check level before applying heat
Dewater oil	90°C									Switch to 50°C when O/P slows
Cool oil	50°C									Titrate oil now. Empty collector.
Inject Methoxide						Adj.				Allow 20 mins to inject.
Reaction Stage										Allow 90 mins at 50C
5% Prewash										Mix 15 mins
Settle Glycerol										Wait 90 mins
Drain Glycerol										Drain slowly to avoid whirlpool
Distil methanol	90°C
Drain Biodiesel	Off						Adj.			Ensure heater is OFF first! Caution - Hot! Wear breathing apparatus. Take sample and perform 23/7 test before discharging whole batch.