Biodiesel process

Smaller plant footprint compared to conventional biodiesel processes. 

World-wide demand for glycerol is projected to be 0.2 Mt in 2007 and is forecasted to grow by 2.2% per year, driven mainly by personal care and food products [10]. If the target of the European Union directive is achieved, European biodiesel demand could increase to 10 Mt per year by 2010, resulting in 1 Mt of glycerol [2]. The price of glycerol has already fallen by 50% over the past ten years [10, 11]. Thus, the application of glycerol, obtained from the biodiesel process,... 

Modifications in the production of biodiesel can result in valuable glycerol as a byproduct and in fewer separation steps. The modifications studied or considered include combining etherification of glycerol into the biodiesel production process, etherification in situ within the biodiesel process and a biodiesel process with heterogeneous catalyst. 

Van Gerpen, J. 2005. Biodiesel processing and production. Fuel Process Teehnol 86 1097-1107. 

Figure 4.32 Simplified schematic of the IFP Esterfif biodiesel process, based on two consecutive reactor/separator stages.

Figure 1.3 The biodiesel process - an example of a phase I biorefinery...

Older biodiesel processes are essentially batchwise. The oil is submitted to transesterification in a stirred-tank reactor in the presence of a large amount of methanol, and base catalyst, mostly NaOH or KOH. An excess of methanol is necessary chiefly to ensure full solubility of triglyceride and keep the viscosity of the reaction mixture low, but also for shifting the chemical equilibrium. A minimum molar ratio methanoktriglyceride of 6 1 is generally accepted [16, 17, 29], The reaction... 

Conventional industrial biodiesel processes are based on homogeneous alkaline catalysts. Sodium hydroxide or sodium methylate are the most often used catalyst in... 

In all cases, for batch homogeneous biodiesel processes, the neutralization step leads to the formation of salts, carried in the glycerol phase, but which need to be disposed of Glycerol from homogeneous biodiesel processes can to some extent be considered as a waste stream. 

Homogeneous biodiesel process Heterogeneous biodiesel process... 

One Oil Extraction Unit (OEU) would be set up for each cluster, and would be responsible for processing the seeds collected from the cluster village as well as extended villages. Each cluster village would support the oil mill to exceed the maximum production capacity. Oil would then be transported to distriets and then to a provincial biodiesel plant. Oil cake would be distributed to farmers to fulfill the loeal supply of organic fertilizer. Exeess cake would be transported to distriets and further to a Provincial Biodiesel Processing Plant for selling to other farmers. 

The small scale or farm-size oil expressing machines are intended for use by individual farmers or groups of farmers (cooperatives) who produce oilseeds such as jatropha, castor beans, sunflower and soya beans. The idea is to extract oil at the farms and then transport it to a biodiesel processing plant located at some centre in a district or province where it would then processed into biodiesel. The farm set-up will comprise an oil expressing machine and filter press to clean the oil. 

The primary soybean oil quality issues for biodiesel production are free fatty acids, moisture, and phosphorus. These correspond well to the requirements for edible oil but bleaching and deodorization are generally not required for biodiesel. It is desirable to have levels of free fatty acid and moisture as low as possible. If both contaminants are <0.1%, there will be no effect on the biodiesel process (Van Gerpen, 2005). In fact, levels of free fatty acids and moisture of 0.5%, as is common for crude as-pressed oil, can be used directly for biodiesel production. However, there will be some additional soap formation during processing that will need to be removed. 

Figure 16.1 shows a schematic diagram of the processes in a biodiesel production facility. It is assumed that the oil has been extracted, degummed and neutralized before entering the biodiesel process. 

---