Biodiesel methanol

Fig. 7.7 Biodiesel, methanol, ethanol, glueose and glycerol to electricity via biofuel cell...

In order to convert the raw oils into useful material, transesterification technology is used. The oil is reacted with a low molecular weight alcohol, commonly methanol, in the presence of a catalyst to form the fatty acid ester and glycerol (Scheme 6.1). The ester is subsequently separated from the glycerol and used as biodiesel, the glycerol being used as a raw material for fine chemicals production. Although the chemistry is simple, in order to make biodiesel commercially viable the process must be... 

The transesterification reactions were conducted in a sealed 250 ml autoclave equipped with a stirrer. The molar ratio of methanol to oil was 12 1, reaction temperature was 200 C-230°C, and the ratio of catalyst to oil was about 2 wt%. Samples were taken out from the reaction mixture and biodiesel portions were separated by centrifuge. 

In our first experiment we decided to test the conversion of sunflower oil into biodiesel (16). Treatment of sunflower oil (1) with NaOMe in MeOH results in formation of a mixtme of fatty acid methyl esters (FAME), also known as biodiesel, and glycerol (2) (Figme 4.3). The reaction was performed with a six-fold molar excess of methanol with respect to sunflower oil at elevated temperatures (60°C) using a basic catalyst (NaOMe, 1% w/w with respect to sunflower oil). The CCS was equipped with a heating jacket to ensure isothermal conditions. The sunflower oil was preheated to 60°C and was pumped at 12.6 ml/min into one entrance of the CCS. Subsequently, a solution of NaOMe in MeOH was introduced through the other entrance at a flow rate of 3.1 ml per minute. After about 40 minutes, the system reaches steady state and the FAME containing some residual sunflower oil is coming... 

Biodiesel is a fuel derived from renewable natural resources such as soybean and rapeseed and consists of alkyl esters derived from transesterification of triglycerides with methanol. In spite of all the advantages of biodiesel, such as low emissiotts, biodegradability, non-toxicity, and lubricity, the major hurdle in penetration of biodiesel is its high cost because of the expensive food grade refined vegetable oil feedstock. 

To produce biodiesel, refined vegetable oils are reacted with methanol in the presence of alkali catalysts such as sodium hydroxide, potassium hydroxide, and sodium methylate. The overall base-catalyzed process has several problems that also... 

Fatty acid methyl esters (FAME) are currently manufactured mainly by trans-esterification with an alcohol, using a homogeneous base catalyst (NaOH/KOH). Methanol is more suitable for biodiesel manufacturing, but other alcohols can in principle also be used, depending on the feedstock available. The... 

Fig. 5.6 C02-savings by use of biofuels made from energy crops according to Schmitz (2003), Quirin et al. (2004), CONCAWE (2006), Hill (2007) and BMELV (2007b). Conversion pathways 1 Straight oil —> Drive 2 Biodiesel —> Drive 3 Grain —> Heat 4 Ethanol —> Drive 5 Ethanol —> Heat Power 6 Ethanol —> Drive 7 Bales —> Heat Power 8 BtL —> Drive 9 Methanol —> Drive 10 Ethanol —> Drive 11 Biogas —> Drive 12 Biogas —> Heat Power 13 Chips — Heat 14 Chips —> Heat Power 15 BtL —> Drive...

The United States passed the Energy Policy Act in 1992. One goal was to reduce the amount of petroleum used for transportation by promoting the use of alternative fuels in cars and light trucks. These fuels included natural gas, methanol, ethanol, propane, electricity, and biodiesel. Alternative fuel vehicles (AFVs) can operate on these fuels and many are dual fueled also running on gasoline. 

Biodiesel (fatty acid methyl ester (FAME)) production is based on transesterification of vegetable oils and fats through the addition of methanol (or other alcohols) and a catalyst, giving glycerol as a by-product (which can be used for cosmetics, medicines and food). Oil-seed crops include rapeseeds, sunflower seeds, soy beans and palm oil seeds, from which the oil is extracted chemically or mechanically. Biodiesel can be used in 5%-20% blends with conventional diesel, or even in pure form, which requires slight modifications in the vehicle. 

Biodiesel is a mixture of methyl esters of fatty acids and is produced from vegetable oils by transesterification with methanol (Fig. 10.1). For every three moles of methyl esters one mole of glycerol is produced as a by-product, which is roughly 10 wt.% of the total product. Transesterification is usually catalyzed with base catalysts but there are also processes with acid catalysts. The base catalysts are the hydroxides and alkoxides of alkaline and alkaline earth metals. The acid catalysts are hydrochloride, sulfuric or sulfonic acid. Some metal-based catalysts can also be exploited, such as titanium alcoholates or oxides of tin, magnesium and zinc. All these catalyst acts as homogeneous catalysts and need to be removed from the product [16, 17]. The advantages of biodiesel as fuel are transportability, heat content (80% of diesel fuel), ready availability and renewability. The... 

Current biodiesel can not be considered as a 100% biomass-based fuel as long as methanol is derived from petrochemical resources. A clean way to solve the biorelated problem is the conversion of glycerol waste from the transesterification process into syngas. In this context, glycerol reforming is a suitable target reaction worthy of study. 

Notably, several types of liquid biofuels exist or are under development and have the potential to replace fossil fuels, especially in the transportation sector. The focus is on organic fuels such as ethanol, butanol, methanol and their derivatives ETBE, MTBE, which can be produced by fermentation, but also biodiesel and liquid biogas, which can provide interesting biomass-based alternatives to diesel and LPG. 

Alternative fuels Liquefied petroleum gases (LPG), Ethanol, 85% (E85), Ethanol, 95% (E95), Methanol, 85% (M85), Methanol, neat (MlOO), Compressed natural gas (CNG), Liquefied natural gas (LNG), Biodiesel (BD), Hydrogen, and Electricity... 

The standard analytical methods for biodiesel methyl ester are time-consuming and often require multiple physical analyzes per sample. NIRS allows for the simple set up of calibrations for multiple important biodiesel qualities such as mono-, di- and triglycerides, residual methanol, glycerol and moisture as well as... 

The transesterification of triglycerides with methanol is a simple and straightforward process. It is commercially practiced worldwide in the production of FAMEs, which have become popular as a replacement for diesel known as biodiesel . The process consists of three separate equilibrium reactions that can be catalyzed by both acids and bases. (4) The overall process is described in Figure 3. Phase separation of the glycerin is the predominant driving force for this process. 

Figure 7 depicts a simplified block flow diagram (BFD) for a typical biodiesel production process using base catalysis. In the first step, methanol and catalyst (NaOH) are mixed with the aim to create the active methoxide ions (Figure 4, step 1(b)). Then, the oil and the methanol-catalyst solution are transferred to the main reactor where the transesterification reaction occurs. Once the reaction has finished, two distinct phases are formed with the less dense (top) phase containing the ester products and unreacted oil as well as some residual methanol, glycerol, and catalyst. The denser (bottom) layer is mainly composed of glycerin and methanol, but ester residues as well as most of the catalyst, water, and soap can also be found in this layer. 

In general, alcohols, such as methanol, ethanol, propanol, butanol, amyl alcohol, etc., can be used with acid-catalyzed transesterifications to obtain high biodiesel yields. " Methanol is preferred due to its low cost and wide availability, but bioderived ethanol would be ideal for the synthesis of a fully biogenerated fuel. On the other hand, the use of heavier alcohols like butanol... 

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