The Purification Feasibilityof GlycerinProduced During BiodieselProduction S. Soulayman, F. Mustafa, and A. Hadbah Higher Institute for Applied Sciences and technology, Damascus, P.O. Box 31983, Syria, E-mail: ssoulayman@hiast.edu.sy ١
Contents INTRODUCTION Typical composition of crude glycerin from biodiesel production Crude Glycerol Refining Problems regarding the decision Glycerol Applications The chemistry of glycerol First proposal Second proposal: enzymatic trans-esterification process Acknowledgments ٢
What is Glycerin? Glycerin (Glycerol) is a clear, odorless, viscous liquid with a naturally sweet taste. It is derived from both natural and petrochemical feedstocks. Glycerin occurs in combined form (triglycerides) in animal fats and vegetable oils and is obtained from these fats and oils during transesterification, such as in biodiesel production. Glycerin currently has over 1500 known uses in many different industries ranging from foods, pharmaceuticals, and cosmetics (USP grade glycerin) to paints, coatings and other industrial types of applications (technical grade glycerin). It continues to be one of the most versatile and valuable byproducts created during biodiesel production. ٣
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Properties Crude Glycerin Technical Glycerin 99.7 -USP Glycerin Glycerol Content 40-88% 98.0 Min 99.70% Ash 2.0% Max N/A N/A Moisture Content N/A 2.0% Max 0.3% Max Chlorides N/A 10 ppm Max 10 ppm Ma Color N/A 40 Max (Pt - Co) 10 Max. (APHA) Specific Gravity N/A 1.262 (@25C) 1.2612 Min Sulfate N/A N/A 20 ppm Max Assay N/A N/A 99.0-101.0% (on dry basis) Heavy Metals N/A 5 ppm Max 5 ppm Max Chlorinated Compounds N/A 30 ppm Max 30 ppm Max Residue on Ignition N/A N/A 100 ppm Max Fatty Acid & Ester N/A 1.00 Max 1.000 Max Water 12.0% Max 5.0% Max 0.5% Max ph (10% Solution) 4.0-9.0 4.0-9.1 N/A DEG and Related Compounds N/A N/A Pass Organic Volatile Impurities N/A N/A Pass Organic Residue 2.0% Max 2.0% Max N/A ٧
Introduction-0-Base Equation 100 kg vegetable oil + 15 kg methanol + 2 kg NaOH = 100 kg biodiesel (methyl ester) + 15 kg glycerol (raw) + 2 kg irresponsive components ٨
Introduction-1-Prospects ٩
Typical composition of crude glycerin from biodiesel production Property Value Unit Genetically modified origin Possible Glycerol content 77 90% wt% A.R. Ash content 3,5 7% wt% A.R. Moisture content 0,1 13,5% wt% A.R. Lower calorific value 14,9 17,5 MJ/kg A.R. Kinematic viscosity 120 mm 2 /s 3-monopropylenediol 200 13.500 ppm Methanol 0,01 3,0% wt% Matter organic non glycerol 1,6 7,5% wt% ph 4,5 7,4 Sulphate 0,01 1,04 wt% Phosphate 0,02 1,45 wt% Acetate 0,01 6,0 wt% Na 0,4 20 g/kg K 0,03 40 g/kg Ca 0,1 65 mg/kg Mg 0,02 55 mg/kg Fe 0,1 30 mg/kg Mn <0,5 mg/kg ١٠
Crude Glycerol Refining Typically produced glycerol is about 50% glycerol or less in composition and mainly contains water, salts, un-reacted alcohol, and unused catalyst (see table). The unused alkali catalyst is usually neutralized by an acid. In some cases, hydrochloric or sulphuric acids are added into the glycerol phase during the re-neutralization step and produce salts such as sodium chloride or potassium sulphate, the latter can be recovered for use as a fertilizer. Generally, water and alcohol are removed to produce 80 88% pure glycerol that can be sold as crude glycerol. In more sophisticated operations, the glycerol is distilled to 99% or higher purity and sold in different markets. After the re-neutralization step, the alcohol in the glycerol phase can be removed through a vacuum flash process or by other types of evaporators. Usually, the alcohol vapor is condensed back into liquid and reused in the process ١١
Problems regarding the decision It can be concluded that the current problems around glycerin are (and with increasing severity): Refinement of glycerin currently is very expensive and complex, which disqualifies the product for high-quality use. The market is overwhelmed with crude glycerin with a price window of 0 to +150 Euro/tonne, with a low-quality application in combustion, digestion and a sharply increasing export to USA and China. 440-580 /tonne glycerin (99,5%) The amount of glycerin production from biodiesel is at 1,9 Mtonnes/yr so high, compared to the current market of 0,9 Mtonnes/yr, that additional high-quality chemical and pharmaceutical applications need to be identified. ١٢
Glycerol Applications Although biodiesel is the desired product from the reactions, the refining of glycerol is also important due to its numerous applications in different industrial products such as moisturizers, soaps, cosmetics, medicines, and other glycerol products. It is one of the few products that has a good reactivity on sump oil, and is extremely effective for washing shearing shed floor, so it can be used as a heavy duty detergent and degreaser. It was reported also that glycerol can even be fermented to produce ethanol, which means more biofuel can be produced. ١٣
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The chemistry of glycerol Glycerol will play a crucial role in future biorefineries ١٥
First proposal In Germany, it is allowed to both use crude and refined glycerin as a feed (pellet) ingredient. The quality demands for the crude glycerin are max. 0,5% methanol and min. 80% glycerin while it is common to use only 2-5% of crude glycerin in the animal feed mix for poultry and pigs. Proposal: Accept these conditions for crude glycerin. ١٦
Second proposal: enzymatic transesterification process -1 ١٧
Second proposal-2 ١٨
CONCLUSIONS Finally, one can mention the following: The production of high purity grade of crude glycerol is economically feasible in local Syrian Conditions. The utilization of produced glycerol in different aspects is urgently important. The presented information are really devoted to open official eye on perspectives of Glycerol Industry. Further studies should be developed to produce high purity glycerolin a pilot scale with meeting the International standards. ١٩
Acknowledgments The authors wish to thank Higher Commission for Scientific Researches for financing a part of this study. They wish also to thank the Directory of Higher Institute for Applied Sciences and Technology for accepting the financing of this project. ٢٠
THANK YOU ٢١