Water Washing WVO with Baking Soda

Tim has been adding baking soda to his WVO wash water for the last six years. Most cleaning methods work better when you start with clean dry oil, but this one works just as well, if not better, on nasty rancid oil that most people avoid. He starts by adding one pound of baking soda to a cubie of clean water. This is poured into a clean drum after the baking soda has completely dissolved. Then, freshly collected oil is added to the drum stopping about 4 inches from the top. A paint stirrer powered by an electric drill mixes everything into a nice creamy peanut butter looking emulsion. At this point the oil is heated to 100°F and kept there until it is transferred to the filtration cart.

Baking soda neutralizes acids in the oil, giving off CO₂ gas as it does. The CO₂ rises to the surface, taking bits of food particles and other trash along with it to form a doughy scummy mat on top of the oil. The bubbling keeps everything mixed while it's still neutralizing acids. After about 7-10 days, it stops bubbling and the mat slowly settles to the bottom.

The Dieselcraft Centrifuge

The Diesecraft Centrifuge is a brand name for a pressure driven centrifuge. There are other brands available. A centrifuge will remove particulates that regular filters miss. It also does a good job of removing free. The evidence is in that it also removes some dissolved water. One of the biggest advantages is cost. If you are good at scrounging up used equipment, it can cost you as little as $200 to setup. If you buy everything new, it can cost you as much as $1000.

Centrifuging can reduce the volume of oil you have on your property, by reducing settling time.  For example if you cut your settling time from two weeks without a centrifuge to one week with a centrifuge, then you cut the volume of oil being settled in half. The main reason for reducing the volume of oil on hand is safety. Vegetable oil is a fuel and has a high energy content and is a fire accelerant, meaning it will cause fires to rapidly spread.

WVO and Water

Lubrication industry experts tell us there are three kinds of water-oil mixtures:

Dissolved Water
Free Water
Emulsified Water

Dissolved water is mixed with the oil on an atomic level. The solubility limit of water in vegetable oil is around 1000ppm to 2000ppm. It varies based on a couple of factors, the most important of which is temperature. The warmer the oil is, the more water it can hold dissolved.

Free water will settle to the bottom of vegetable oil in a reasonable amount of time.

Emulsified water is water that either will not settle out with gravity alone or will take an absurdly long time to settle out. Vegetable oil will not form a stable emulsion without an emulsifier being present. Emulsifiers are things like food particles, degraded oil, and hydrogenated oil.  Hydrogenated oil was actually designed to form a stable emulsion with water to make margarine and extend shelf life.

The Frybrid Still

This is Clay's filtration setup as he posted it on the Biofuels Technologies Forum under Filtration. It is based on the popular Frybrid Still. The Frybrid website has construction instructions including parts lists and diagrams.

Freshly collected oil goes in the prefilter drum on the right. Once the drum has enough in it to process, It is pumped into the water heater to be heated. Heating the oil frees up some of the emulsified water allowing it to settle to the bottom of the still where it is drained into a cubbie. The remaining dry oil is circulated through a filter to remove particulates and the water trapped in the particulates. The large tote is for storing clean dry oil until it is used. It has two pumps. One for the still, and one to pump oil from the tote to  the vehicle.

The Super Sucker

Submitted by Dana Linscott

Well water pressure tanks (sometimes referred to as captive air pressure tanks) are what is recommended for use as the collection tank. This is mainly because they can often be obtained for free (or scrap value) from plumbers and domestic well drillers/installers in areas not served by a municipal water system. The ones made of steel are also lighter than most of the alternatives yet capable of holding a very high vacuum. Be aware that some fiberglass pressure tanks have been known to delaminate and implode under vacuum. An imploding tank is not dangerous but IS messy.  Nearly any other steel pressure tank will work but thin wall water heaters have been known to crush under vacuum as do common steel or plastic storage drums.