Biodiesel Production PDF

Biodiesel production Dr. Srijoni Banerjee DEPARTMENT OF BIOTECHNOLOGY Adamas University 1  Biodiesel  ASTM International defines biodiesel as a mixture of long-chain monoalkylic esters from f...

Biodiesel production Dr. Srijoni Banerjee DEPARTMENT OF BIOTECHNOLOGY Adamas University 1  Biodiesel  ASTM International defines biodiesel as a mixture of long-chain monoalkylic esters from fatty acids obtained from renewable resources, to be used in diesel engines, alone or blended with diesel oil  Blends with diesel fuel are indicated as ‘‘Bx’’, where ‘‘x’’ is the percentage of biodiesel in the blend.  For instance, ‘‘B5’’ indicates a blend with 5% biodiesel and 95% diesel fuel http://www.aa1car.com/blog/biodiesel.htm  Advantages of the use of Biodiesel  Renewable fuel, obtained from vegetable oils or animal fats.  Low toxicity, in comparison with diesel fuel.  Degrades more rapidly than diesel fuel, minimizing the environmental consequences of biofuel spills.  Lower emissions of contaminants: carbon monoxide, particulate matter, polycyclic aromatic hydrocarbons, aldehydes.  Lower health risk, due to reduced emissions of carcinogenic substances.  No sulfur dioxide (SO2) emissions.  Advantages of the Use of Biodiesel  Higher flash point (100°C minimum).  It is the only alternative fuel that can be used in a conventional diesel engine, without modifications.  Used cooking oils and fat residues from meat processing may be used as raw materials http://efmychem.blogspot.in/2016/05/biodiesel-research.html https://metaefficient.com/uncategorized/biodiesel-faq.html  Raw materials for biodiesel production  Feedstock:  Non-edible and recycle cooking vegetable oils, animal fats  Vegetable oils are rapeseed (EU), soybean (Argentina and USA), palm (Asian and Central American) and sunflower  Although other oils are also used, including peanut, linseed, safflower, used vegetable oils  Microalgae appear to be a very important alternative for future biodiesel production due to their very high oil yield  Raw Materials for Biodiesel Production rapeseed soybean palm sunflower https://en.wikipedia.org/wiki/  Raw Materials for Biodiesel Production  Alcohols:  Methanol: Most widely used, in spite of its toxicity. It is a substance of petrochemical origin.  Ethanol: Less used, requires more complex production technology and the reaction speeds Difficulties ariseare in lower. It can the phase be produced separation from biomass and purification of biodiesel when ethanol is used in the reaction  Raw Materials for Biodiesel Production  Catalyst:  Basic: Most frequently used at all production scales. Like sodium hydroxide (NaOH), potassium hydroxide (KOH), carbonates and their corresponding alcoxides  Acid: Less frequent in industrial production, sometimes used a first stage with highly acidic raw materials. Like sulfuric acid, sulfonic acids and hydrochloric acid  Enzymatic: Less used; the enzymes are usually lipases. Characteristics of oils and fats used in biodiesel production  Oils and fats, known as lipids, are hydrophobic substances insoluble in water and are of animal or vegetal origin  From a chemical viewpoint, lipids are fatty glycerol esters known as Triglycerides  R1, R2 and R3 represent hydrocarbon chains of fatty acids Characteristics of Oils and Fats Used in Biodiesel Production  Fatty acids may be saturated fatty acids (SFA) or non-saturated fatty acids (NSFA)  The most frequent fatty acids in oils are lauric, palmitic, estearic, linoleic and linolenic, although others may also be present  Vegetable oils may also contain small percentages of monoglycerides and diglycerides  Characteristics of Alcohols Used in Biodiesel Production  Alcohols that can be used in biodiesel production are those with short chains, including methanol, ethanol, butanol, and amylic alcohol  The most widely used alcohols are methanol (CH3OH) and ethanol (C2H5OH) because of their low cost and properties  Methanol: Most widely used, in spite of its toxicity. It is a substance of petrochemical origin.  Ethanol: Less used, requires more complex production technology and the reaction speeds are lower. It can be produced from biomass.  Biodiesel production process  Biodiesel is produced from vegetable oils or animal fats and an alcohol, through a transesterification reaction.  This chemical reaction converts an ester (vegetable oil or animal fat) into a mixture of esters of the fatty acids that makes up the oil (or fat).  Biodiesel is obtained from the purification of the mixture of fatty acid methyl esters (FAME).  A catalyst is used to accelerate the reaction.  According to the catalyst used, transesterification can be basic, acidic or enzymatic Steps involved in biodiesel production process  Treatment of raw materials  Alcohol-catalyst mixing  Chemical reaction (transesterification)  Separation of the reaction products  Purification of the reaction products  Treatment of Raw Materials  Some feedstocks must be pretreated before they can go through the transesterification process.  Feedstocks with less than 4% free fatty acids, which include vegetable oils and some food-grade animal fats, do not require pretreatment.  Feedstocks with more than 4% free fatty acids, which include inedible animal fats and recycled greases, must be pretreated in an acid esterification process.  Treatment of Raw Materials  In this step, the feedstock is reacted with an alcohol (like methanol) in the presence of a strong acid catalyst (sulfuric acid), converting the free fatty acids into biodiesel.  The remaining triglycerides are converted to biodiesel in the transesterification reaction  Alcohol-Catalyst mixing  The alcohol used for biodiesel production must be mixed with the catalyst before adding the oil.  The alcohol must be water-free (anhydrous)  The alcohol-to-oil volume ratio, R, is another key variable of the transesterification process.  Advisable alcohol-to-oil volume ratio is 1:4  The necessary amount of catalyst is determined taking into account the acidity of the oil, by titration  Chemical reaction (transesterification)  A generic transesterification reaction is presented as follows RCOOR' + R"OH ↔Catalyst R'OH + RCOOR"  When methanol is the alcohol used in the transesterification process, the product of the reaction is a mixture of methyl esters  If ethanol were used, the reaction product would be a mixture of ethyl esters  In both cases, glycerin will be the co-product of the reaction Chemical reaction (transesterification) KOH ↔ KOH ↔  Chemical reaction (transesterification)  The temperature for transesterification at atmospheric pressure is usually in the range between 50 and 60°C.  The absence of mono- and diglycerides at the beginning of the chemical reaction, the reaction confirm that the production of esters from the triglycerides takes place in three steps  Where MOH indicates methanol, ME are the methyl esters, TG, DG and MG are tri-, di- and monoglycerides, respectively, and G is the glycerol  Separation of the Reaction Products  The separation of reaction products takes place by decantation: the mixture of fatty acids methyl esters (FAME) separates from glycerol forming two phases (because of different densities)  FAME floats up at the top while glycerol settles down at the bottom. the two phases may be physically separated  In some cases, a centrifuge is used to separate the two materials faster.  Purification of the reaction products  After the separation of glycerol, the FAME mixture contains impurities such as remnants of alcohol, catalyst and unreacted oil  These impurities confer undesirable characteristics to FAME, for instance, increased cloud point and pour point, lower flash point, etc.  In consequence a purification process is necessary for the final product to comply with standards  The FAME mixture (Biodiesel) first washed gently with warm water to remove residual catalyst or soaps, dried and then sent to the distillation section for further purification  Purification of the reaction products  Separated glycerin contains usually 50% glycerine, 40% methanol and 10% soap and catalyst  First it is washed then sent to salt removal unit and then distillation unit  Non- Free Fatty CH3OH Biodies Unreacte edible Acid el d oil oil/fat Acid+CH Pre- 3O processing Acid Distillation H Base unit catalyst Transesterificati Neutralizati Washin + Phase on on & g& CH3OH Separation Reactor Settling Washin drying Oil/fat g Salt Removal Salt Steps involved for CH3OH Biodiesel production Distillation unit Fertilizer Pharmaceutic Glycerol al industries Steps for mixotrophic biodiesel production from algal biomass Biohydrogen Production in 20L bench scale reactor Spent Media Biomass production in customized Airlift Shake flaskphotobioreactors Flat panel Biodiesel Lipid Extraction Algal Production Biomass Harvesti ng  Glycerol  Main by-product of biodiesel production  Glycerol is the usual name of 1,2,3-propanetriol; it is also referred to as glycerin or glycyl alcohol  Uses of Glycerol  In the pharmaceutical industry, for the manufacture of ointments, creams and lotions  In the food industry, for the manufacture of sweets, soft drinks, and pet foods and in the conservation of canned fruit  As an additive in the manufacture of soaps, to improve their properties  In the manufacture of nitroglycerin for the production of explosives  Concluding Remarks  A key environmental benefit of using biofuels as an additive to petroleum- based transportation fuels is a reduction in harmful emissions  Making biodiesel from soybeans reduces net emissions nearly 80%.  Microalgae grown in ponds and photobiological reactors have also great potential for the production of oils for biodiesel production  The stages of the biodiesel production process are the same for all the production scales (laboratory, pilot plant, small-, medium-, and large-scale industrial). However, the necessary equipment will be significantly different  Biodiesel Economics  According to industry sources back in 2007, biodiesel costs about $1 a gallon more to produce than conventional diesel fuel when soybean oil is used as the primary ingredient.  This makes the fuel about 10% more expensive than conventional diesel ($3.13 a gallon for biodiesel versus $2.70 a gallon for conventional diesel 2007 prices).  It needed tax breaks to compete with petroleum-based diesel fuel. http://www.aa1car.com/blog/biodiesel.htm  Biodiesel Economics  As of October 2013, diesel fuel is selling around $3.85 per gallon and biodiesel is less expensive to produce than conventional diesel.  Consequently, many truck stops are selling biodiesel blends because they are more profitable than straight diesel fuel.  Biodiesel has relied on federal tax breaks to make it economically viable. As long as the tax breaks continue, biodiesel probably has a strong future http://www.aa1car.com/blog/biodiesel.htm Thank You!! 31