Biodiesel production from tallow

A focus area for this meeting was a discussion of new approaches to life cycle analyses of biobased processes is described in three papers. Anex reports an evaluation of processes for the production of 1,3-propanediol. Niederl describes an analysis of biodiesel production from tallow, while the paper from Bohimann reports on life cycle issues surrounding polyhydroxylalkanoate production. 

Apart from a few reports" on solid acid catalyzed esterification of model compounds, to our knowledge utilization of solid catalysts for biodiesel production from low quality real feedstocks have been explored only recently. 12-Tungstophosphoric acid (TPA) impregnated on hydrous zirconia was evaluated as a solid acid catalyst for biodiesel production from canola oil containing up to 20 wt % free fatty acids and was found to give ester yield of 90% at 200°C. Propylsulfonic acid-functionalized mesoporous silica catalyst for esterification of FFA in flotation beef tallow showed a superior initial catalytic activity (90% yield) relative to a... 

Chakraborty, R., Sahu, H., 2014. Intensification of biodiesel production from waste goat tallow using infrared radiation process evaluation through response surface methodology and artificial neural network. Applied Energy 114, 827—836. Available at http //www. sciencedirect.eom/science/article/pii/S030626191300319X (accessed 01.03.15.). 

Ecological Evaluation of Processes Based on By-Products or Waste from i riculture Life Cycle Assessment of Biodiesel from Tallow and Used... 

When starting a Life Cycle Assessment the first task is the definition of goal and scope. As already mentioned the setting of system boundaries for products based on renewable resources is not straightforward. In order to exemplify die influence of the question what shall be included on the result of the assessment three different scenarios will be compared for the life cycle of biodiesel from tallow and used vegetable oil (see Figure 1). 

The function of the products biodiesel from tallow (TME - tallow methyl ester) and biodiesel from used vegetable oil (UVO) is to serve as fuel for combustion in (unspecified) motor vehicles. The functional unit used to quantify this function is the combustion energy (calorific value) of biodiesel. The reference flow is 1 MJ combustion energy. 

The scope of this LCA study considers the provision of the product biodiesel from tallow (TME) and biodiesel from used vegetable oil (UVO) from raw material extraction to the usage of the finished product (resulting in vehicle emissions caused by fuel combustion). The scope here is therefore a cradle-to-wheel LCA. The production of energy, raw materials and auxiliary materials is included as is the waste disposal and the treatment of liquid and gaseous emissions during all steps of the life cycle. The production and operation of die infrastructure needed in the provision of the function is excluded from the LCA as it has turned out to be of minor influence (see Figure 1). 

Scenario II In contrast to the previous setting, the system boundaries for biodiesel from tallow are set outside the gate of the slaughtering house. Rendering products leaving the slaughtering process are considered as waste-stream comparable to UVO in scenario I. These render products are... 

Table 1. Multi-Output Processes in the Production of Biodiesel from Tallow...

Table I shows the multi output process of the biodiesel from tallow model. Four processes have more than one economic output. For the life cycle of biodiesel from used vegetable oil only the two letter processes (transesterification and KOH-production) are relevant.

When allocating the render products that come out of the slaughterhouse by mass compared to meat, hides or other by-products, the agrarian chain has the most important environmental impact for TME. Price allocation leads to a reduction in the overall footprint per MJ energy resulting from combustion of TME of 37.79 m2a/MJ to 8.28 m2a/MJ. The absolute footprint (as shown in Figure 4) of biodiesel from tallow in scenario III with mass-allocation applied would be higher than fossil diesel. 

Analysing scenario III the agrarian chain consists of the slaughtering process and cattle-breeding. Here the cattle-breeding plays an outstanding role in the production of biodiesel from tallow, where the main part of the cattle-breeding footprint can be attributed to fodder-production and emission of ammonia. 

Animal edible tallow is normally obtained from beef but also from sheep and goats, processed from suet. Unlike suet, tallow can be stored for extended periods without the need for refrigeration to prevent decomposition, provided it is kept in an airtight container to prevent oxidation. It is used in animal feed, to make soap, for cooking, as bird feed, and was used for making candles. It can be used as a raw material for the production of biodiesel and other oleochemicals. ... 

As mentioned earlier, the quality of the feedstock has a significant effect on the reaction yield, where FFAs and moisture contents are key parameters in defining feedstock feasibility. For example, the alkali-catalyzed production of biodiesel from duck tallow at 65°C and a 6 1 methanol-to-oil molar ratio resulted in a 62% conversion (Chung et al 2009), whereas sunflower resulted in an 86% conversion using the same catalyst under the same conditions (Vicente et al., 2004). 

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