Food Waste and Catering Waste; Focus on Valorisation of Used Cooking Oil and Recovered Triglycerides - The Economic Utilisation of Food Co-Products - page 102

biodiesel and has been commercially demonstrated by Neste Oil. 62,63 A recent
study from Norwegian researchers has reviewed and compared environmental
impact, life-cycle assessments and costs between different biodiesel fuels
(transesterified lipids, hydrotreated vegetable oils and woody biomass-to-liquid
Fischer-Tropsch diesel) and come to the conclusion that hydrotreated oils from
waste or by-products including tall oil, tallow or waste cooking oils outperform
any other diesel product in terms of environmental LCA impact and costs. 64
In Greece, Bezergianni et al. have recently described how the production of
hydrogenated green diesel from waste oils can take place in high yields (495%)
using typical commercially sulfided Ni-Mo catalysts. 61 Low-pressure values
generally maximise biohydrogenated diesel production as opposed to high
temperatures that favour cracking reactions. In all cases, the heteroatom
removal in the systems was quite ecient, exceeding 99% for sulfur and
nitrogen and over 90% for oxygen.
The main drawback of this methodology is the use of hydrogen in systems
that generally require high pressures. Unless it can be obtained from a
renewable resource (e.g. via aqueous phase reforming of another waste residue/
renewable feedstock), the proposed approach cannot be commercially feasible.
In this regard, coupling an APR approach with oil hydrotreatment processes
could be the ideal sustainable solution for the valorisation of waste oils.

d n 9 r 3 n g | 0

d y y f n n 3 .

6.5.4 Beyond Fuels, Use of Recovered Triglycerides as Chemical
Feedstocks
Biodiesel and the use of UCO as a fuel precursor, are the most common
valorisation routes for UCO, however cost, availability and the properties of
this food coproduct and other recovered triglycerides have facilitated the
development of alternative technical uses to the transformation into biofuel in
many industrialised countries (Figure 6.11).

Figure 6.11 Volumes of lipid-derived technical products in Germany. 69