In 1993, the influence of 3-30% rapeseed oil in vacuum distillate FCC feed on product slate and quality both at laboratory and at a continu­ously operated bench-scale apparatus was reported for the first time [41]. On the one hand, results showed decreasing yields of liquid hydro­carbons with increasing rapeseed oil concentrations. On the other hand,

the gasoline portion in the liquid product increased. Considering propenes, butanes, and i-butenes as gasoline potentials, low rapeseed oil portions in the FCC feed seem to result in an optimum yield of gaso­line plus gasoline potentials. Most interestingly, the gasoline fraction recovered from a 500-h bench scale run using a feed with 30% rapeseed oil proved suitable for standardized gasoline blending. Calcium con­centration c(Ca) > 2 ppm gradually decreases FCC catalyst activity. Oxygen contained in the vegetable oil was mainly converted to water. Moreover, traces of phenols and carboxylic acid were detected in the liquid reaction product.

MAT with animal fat. In a laboratory scale, mixtures of vacuum gas oil and up to 15% of animal fat were converted in a Micro-Activity Test (MAT) unit [37]. Results are given in Figs. 8.16 and 8.17. Two aspects are of special interest. First, yields of propene and butene increase with animal fat as a co-substrate. This is an advantageous finding as C-3 and C-4 are gasoline potentials. C-3 and C-4 liquefied petroleum gas can be used for the manufacture of isoparaffins for motor gasoline through alkylation and polymerization processes.

Second, a higher yield of gasoline fraction is observed. This is a con­sequence of the high hydrogen:carbon ratio of about 2 and the low het­eroatom content. For this reason, biomaterials with a hydrocarbon-like structure are particularly interesting candidates for conversion to low — molecular-weight fuels or chemical raw materials. Problems to be inves­tigated are possible calcium and phosphate deposits on the catalyst particles which may impair catalyst activity and process stability of the riser. Therefore, the process must include a regeneration step. The market will decide whether or not animal fat can substitute a bit of non­renewable resources in petroleum refining.

Animal fat (%) in VGO