TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: The basic solution is an aqueous solution of lithium hydroxide (LiOH), magnesium hydroxide (Mg(OH)2) or calcium hydroxide (Ca(OH)2) (preferably calcium hydroxide or lithium hydroxide. The acid catalyst is selected from sulphuric acid (H2SO4), sulphamic acid (H2NSO3H), hydrochloric acid (HCl), phosphoric acid (H3PO4), or sulphated metal oxides such as sulphated zirconia. The inert gas is nitrogen. The catalyst is silica sand.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Method: The thermal cracking is conducted at 390 - 460 (preferably 410 - 430)degreesC. The middle distillate fraction is esterified in the presence of alcohol (preferably methanol) and an acid catalyst. The esterifying is conducted at 70 - 120 (preferably 85 - 110)degreesC. The method further comprises filtering the triglyceride feedstock before thermal cracking to remove macroscopic contaminant particles. The rapid pyrolysis is conducted at 480 - 600 (preferably 550 - 600, especially 565 - 585)degreesC. The triglyceride feedstock is fluidized with steam, where the steam to triglyceride feedstock ratio of 0.5 - 1.5 (preferably 0.9). An inert gas is used to purge any oxidizing agents during rapid pyrolysis. A catalyst is used during rapid pyrolysis to enhance the cracking of triglycerides to largely free fatty acids. Preferred Components: The triglyceride feedstock is selected from restaurant trap grease, rendered animal fats, waste greases and/or low-quality vegetable oils. The acid catalyst is selected from formic acid (HCO2H), acetic acid (CH3CO2H), propionic acid (CH3CH2CO2H) or styrene divinylbenzne copolymers having SO3H functional groups (preferably the styrene divinylbenzene copolymer). The catalyst is selected from acid washed activated carbon or calcined sewage sludge solids. EXAMPLE - Conversion of restaurant trap grease into mixed biodiesel/diesel product as follows: Restaurant trap grease having an average density of 0.925 g/ml was fed to a thermal cracking unit and cracked at 418.5degreesC. and a pressure of 29 psig (301 kPa) for 40 minutes. Thermal cracking produced a gas stream, a naphtha stream, a middle distillate stream with a maximum boiling point of 343degreesC, as well as water and residue. The middle distillates stream made up 63.0 wt.% of the total cracked product and had an acid number of 83.93 mg KOH/g. The middle distillate stream was then fed to an acid esterification unit, where it was contacted with methanol in the presence of an amberlyst 36 catalyst. Esterification was conducted at 90degreesC nd at atmospheric pressure for 20 hours. Esterification produced a raw diesel stream which was then treated with a calcium hydroxide solution to produce a final mixed biodiesel/diesel product having an acid number of 0.45 mg KOH/g. The final product have nitrogen (0.22 wt.%), sulphur (136 parts per million) and a viscosity of 5.02 cSt. The sulphur content and viscosity being well within ASTM 6751 standards for biodiesel.