Reply #8: Well, I can give you the experimental details from the paper, but I don't know

[NNadir]

that it would be particularly useful.

You should know that not all oils are created equal. Rapeseed has a different chemical composition than soy oil. The source oil does have an effect on cloud point. Thus if you are using rapeseed oil you may have a different result than if you are using soy oil. Some of these differences have lead to some difficulties. Volkswagen at one time - I don't know if it is still the case - was voiding warranties on vehicles fueled with American soy based biodiesel based on the American fuel specifications. European biodiesel tends to be rapeseed derived or, many times, imported palm oil based.

The paper refers to soy oil prepared by the traditional lye method.

The best zeolite catalyst was a synthetic zirconium based zeolite. Here is a description of the catalyst preparation.

Zirconium hydroxide was prepared by precipitation of ZrOCl2â8H2O (Strem Chemicals, 99.99%) first dissolved in water. Ammonia was added dropwise until a pH of 10 was reached. The Zr(OH)4 gel formed was then filtered and dried overnight at 110 °C. The dried xerogel was sulfated by immersing it in a 2 N H2SO4 (10 mL gcat -1) solution for 1 h. Then, it was calcined in air (10 mL min-1, 600 °C, 3 h). The thus produced SO4 2--ZrO2
catalyst was dried overnight and finally ground and sieved to 35-80 meshes.

According to the paper, the best result was obtained by stirring this catalyst vigorously with nitrogen flushing in a stainless steel autoclave at 150C for 1 hour. The catalyst was filtered and the biodiesel's cloud point was reduced to -2C, just below the freezing point of water. I'm sure you have colder days than that in Montana.

If I were you, I wouldn't necessarily try this at home. It might be simpler to use B100 in summer and B20 or B5 in winter.

If you do try this, come back and let us know how it worked out. My guess is that biodiesel is overall a better deal than ethanol, but officially I'm agnostic about biofuels.