Purification Of Glycerol Research Articles

Purification of Crude Glycerol Recovered From Fish Processing Waste Biodiesel Process

Biodiesel and crude glycerol are byproducts of the esterification and transesterification reactions that occur between triglyceride molecules and alcohol in the presence of acid and base catalysts. Purification of crude glycerol is necessary to increase the economic sustainability of the biodiesel industry. This study was carried out for pre-treatment of crude glycerol sourced from fish processing waste during biodiesel manufacturing, treated through an acidification process using phosphoric acid (H3PO4), and then using further purification treatment with Jatropha curcas bio-adsorbent. Based on the measurement, the quantity of 0.1% phosphoric acid (H3PO4) solution was required to treat the crude glycerin. The reaction conditions include heating solution to 60°C and stirring it at 40 rpm for varying treatment periods such as 15, 30, 45, and 60 min. The crude glycerol's pH was adjusted to begin the acidification process, and soap was then converted into fatty acids and salts using phosphoric acid. The maximum purified glycerol yield of 76.6% by weight was obtained with treatment time of 15min using vacuum distillation at 120°C. The crude and purified glycerol’s density was measured as 1.013 g/mL and 1.001 g/mL, respectively. However, after bio-adsorbent treatment at temperature of 50°C and 10% loading weight of the Jatropha curcas bio-adsorbent, the best impurity elimination was accomplished in 15 min. The research findings demonstrated that, following acidification and bio-adsorbent treatments, the FFA% decreased from 2.82% to 2.24%, while its density increased from 1.002 g/mL to 1.032 g/mL, respectively. The purified glycerol properties were found in accordance with BS 2621-1979 standard, showing that the acidification method for purifying of crude glycerol, in conjunction with bio-adsorbent treatment is efficient in enhancing the glycerol purity. It also improves glycerol's application in generating high-value products that enhance revenue streams for the biodiesel production.

Purification of biodiesel-derived crude glycerol and its application in plasticizing cassava starch bioplastics

This study focused on purifying crude glycerol, a by-product of biodiesel production, using acid-precipitation, methanol extraction, and adsorption with acid-activated charcoal. Among the acids tested—sulfuric, phosphoric, and hydrochloric—phosphoric acid proved most effective, producing the clearest glycerol with minimal salt deposition. The purified glycerol was then used to produce bioplastics, which were tested for mechanical properties. The results indicated that Phosphoric acid yielded the clearest glycerol with minimal salt deposition. The resultant salt, potassium phosphate (K2PO4), has potential as a fertilizer. The purified glycerol showed increased density and viscosity, indicating higher purity compared to crude glycerol. The density of the purified glycerol was closer to that of analytical-grade glycerol. Bioplastic 1 (using analytical-grade glycerol) exhibited the highest tensile strength, withstanding up to 4.3N and extending about 104mm before breaking. Bioplastic 2 (using glycerol purified with hydrochloric acid) withstood up to 4.1N, while Bioplastic 3 (using glycerol purified with acetic acid) endured the least stress, withstanding up to 3.8N and extending up to 87mm before breaking. The study demonstrates that phosphoric acid is an effective agent for purifying crude glycerol, significantly enhancing its quality. The purified glycerol, in turn, improves the mechanical properties of bioplastics, making them more durable and suitable for a range of applications. This process not only adds value to the biodiesel production by-product but also contributes to the development of stronger, more versatile bioplastics.

Purification of crude glycerol derived from biodiesel production process using ceramic membranes: Experimental studies and modeling of flux behavior

Large-scale biodiesel production generates large quantities of glycerol with high impurities levels, and new purification processes are needed to add value to this by-product of biodiesel production. Thus, this study evaluated the application of ceramic membranes for glycerol purification from biodiesel production and the influence of the mean pore diameter of the membrane, pressure, temperature, and the addition of acidified water to the mixture to be purified. The experiments were carried out in a tangential filtration module with ceramic membranes of 5 kDa, 20 kDa, 0.05 μm, and 0.2 μm, varying the pressure by 1, 2, and 3 bar and the temperature by 25, 40, and 60 °C. The results showed that increasing the pressure, average pore diameter and temperature caused an increase in the permeate flux. Furthermore, adding acidified water increased permeate fluxes and glycerol concentrations for all membranes and pressures used. A higher glycerol content (91.13 %) was obtained with the 5 kDa membrane at 3 bar and 60 °C. The traditional fouling mechanism models failed to fit most of the experimental data. On the other hand, the proposed generalized model adequately predicted the experimental permeate flux data for the different types of fouling mechanisms observed.

Optimization of crude glycerol purification from grease trap waste biodiesel production: exploring the synergistic effect of mixed extraction alcohols on enhanced glycerol purity

AbstractBACKGROUNDThe purification of crude glycerol, a byproduct of biodiesel production and grease trap waste, is essential for its utilization in high‐value applications. Achieving exceptionally pure glycerol without relying on energy‐intensive vacuum distillation during transesterification is of substantial economic interest.RESULTSThis investigation focuses on crafting a purification process involving chemical treatment (neutralization), adsorption and extraction. The assessment of the neutralization process using sodium hydroxide (NaOH) and potassium hydroxide (KOH) revealed their comparative efficacy. Activated carbon adsorption was used to reduce coloration in crude glycerol, with weights set at 4 and 8 wt%. Efficient salt extraction from crude glycerol was explored using solvents such as methanol, ethanol and isopropyl alcohol in varying mass ratios to crude glycerol (1:1 and 2:1). The study also examined the synergistic effects and impact of mixing alcohol solvents. Optimal conditions for achieving high purity (92.44%) were identified as the combination of KOH, 8 wt% activated carbon and a 2:1 ratio of a mixture of the three alcohols.CONCLUSIONThe combined effects of employing a mixture of alcohols significantly enhance the extraction process, resulting in the efficient and successful purification of glycerol. These outcomes offer valuable insights into improving the extraction process in industrial settings, leading to the production of high‐quality glycerol products. © 2024 Society of Chemical Industry (SCI).

Simulation and optimization of crude glycerol refining process as a co-product of biodiesel

Glycerol is an essential chemical raw material widely used in industries such as food, pharmaceuticals, cosmetics, tobacco, and textiles. With the increasing production of biodiesel, a considerable amount of crude glycerol co-product is generated. Purification of crude glycerol by separating it from biodiesel co-products can lead to the production of high-purity glycerol, thus enabling the synthesis of high-value-added chemicals to reduce the production cost of biodiesel. This paper proposes a new glycerol purification process based on the acidification of potassium oleate soap using sulphuric acid. The composition of crude glycerol is complex. The presence of salts can affect the binary interaction parameters of glycerol and water. The ion forms resulting from the ionization of potassium fatty acid soaps are not available in the database and require important data to be provided through physical property estimation. Additionally, the dissociation of sulphuric acid is involved in the system. These issues make it challenging to propose a complete process based on the characteristics of crude glycerol. In this study, the vapor–liquid equilibrium data of the glycerol-water system containing potassium sulphate under reduced pressure were experimentally determined, and the binary interaction parameters of the glycerol-water system were regressed and used in the subsequent process simulation. The entire process of crude glycerol refining from biodiesel co-products was simulated and optimized using Aspen Plus software, proposing an optimized complete refining process for crude glycerol and designing a crude glycerol refining process with a production scale of 100,000 tons per year. The potassium oleate soap is first acidified with sulphuric acid, then removed by centrifugation, with the resulting lower layer entering the distillation process. We compared two different distillation processes and identified the more optimal separation sequence. Glycerol products with a mass concentration of 99.2% were obtained, with glycerol and methanol yields of 98.83% and 99.79%, respectively. Based on the above research, energy integration and optimization of the process were further investigated through pinch analysis. Overall, energy savings of 7.192 Gcal/h were achieved, resulting in a reduction in energy consumption of 40.65%. This paper proposes a new purification scheme for crude glycerol and an energy integration scheme to reduce the purification cost of high-purity glycerol. This is significant for the rational utilization of crude glycerol, a co-product of biodiesel.

Waste‐derived low‐grade glycerol purification and recovery from biorefineries: an experimental investigation

AbstractA combination of different physio‐chemical treatment steps was applied to purify industrially derived crude glycerol at laboratory scale. The full process included acid–base treatments, phase separation, and adsorption, and the glycerol purity and recovery were optimized by varying the pH during saponification and acidification, the solvent‐to‐glycerol ratio, and type of base used in the process to enhance both. The testing campaign resulted in a final purity of up to 87% wt starting from a very low‐quality ‘end‐of‐life’ waste glycerol sampled from different refineries. The net glycerol recovery at laboratory scale reached 42% of the initial glycerol in the feedstock and the maximum ash removal exceeded 90% given the low quality of the feedstock and high content of impurities and the attempt to achieve high glycerol recovery. The experiment showed that mild operations such as saponification with KOH (pH of 8), acidification with H3PO4 (pH of 6), an ideal 2‐propanol to glycerol volume ratio equal to 3 and potassium hydroxide as a base for the neutralisation step were the optimum conditions despite the differences between samples. The sequence of the processes proposed was therefore considered a viable option to treat any kind of crude glycerol to make it profitable for fuel and chemical applications.

Experimental Scale-Up and Technoeconomic Assessment of Low-Grade Glycerol Purification from Waste-Based Biorefinery.

The purification of waste-derived crude glycerol to the 2000 g scale is presented to provide a consolidated proof of concept. Starting from unprecedented low-quality glycerol from a second-generation biodiesel plant, currently disposed of at cost, a series of physiochemical steps are implemented to improve glycerol purity and recovery under relevant conditions. The study is carried out on two samples with initial purities of 38-57 wt % and ash contents of up to 16 wt %. Under the optimal process conditions, glycerol exhibits a remarkable increase to 85 wt % purity while preserving the overall glycerol recovery of the process of up to 71%. Among different purification steps, neutralization contributes to increasing the purity to 69 wt % while the remaining water and methanol evaporation have further increased the purity to >80 wt %. The adsorption step shows the smallest increase in glycerol purity despite it being required to decolorize and deodorize the final product. The developed process is further designed for industrial-scale application using Aspen Plus for a plant size of 1630 kg/h of purified glycerol which could achieve 82 wt % final purity and a maximum recovery of 77%. In addition, the process yields 315 kg/h of salable byproduct salts suitable as fertilizer and an overall CO2 emission of 0.70 ton per ton of purified glycerol mainly due to the unrecovered feedstock and solvent combustion. As a result, the proposed process implementation could generate positive revenues with a cost of the final products of €19.2 per ton.

Environmental impacts of valorisation of crude glycerol from biodiesel production – A life cycle perspective

Biodiesel production produces significant quantities of impure crude glycerol as a by-product. Recent increases in the global biodiesel production have led to a surplus of crude glycerol, rendering it a waste. As a result, different methods for its valorisation are currently being investigated. This paper assesses the life cycle environmental impacts of an emerging technology for purification of crude glycerol – a multi-step physico-chemical treatment – in comparison to incineration with energy recovery commonly used for its disposal. For the former, three different acids (H3PO4, H2SO4 and HCl) are considered for the acidification step in the purification process. The results suggest that the H2SO4-based treatment is the best option with 17 net-negative impacts out of the 18 categories considered; this is due to system credits for the production of purified glycerol, heat and potassium salts. In comparison to incineration with energy recovery, the H2SO4-based process has lower savings for the climate change impact (−311 versus −504 kg CO2 eq./t crude glycerol) but it performs better in ten other categories. Sensitivity analyses suggest that that the impacts of the physico-chemical treatment are highly dependent on crude glycerol composition, allocation of burdens to crude glycerol and credits for glycerol production. For example, treating crude glycerol with lower glycerol content would increase all impacts except climate change and fossil depletion due to the higher consumption of chemicals and lower production of purified glycerol. Considering crude glycerol as a useful product rather than waste and allocating to it burdens from biodiesel production would increase most impacts significantly, including climate change (22–40 %), while fossil depletion, freshwater and marine eutrophication would become net-positive. The findings of this research will be of interest to the biodiesel industry and other industrial sectors that generate crude glycerol as a by-product.

Purification and use of crude green glycerol from the transesterification of triglycerides in the formulation of an alcohol gel hand sanitizer

The aim of this study was to produce an alcohol gel hand sanitizer containing green glycerol. Crude glycerol was purified using chemical and physical treatments. The sanitizer was prepared using 71.100 g of 99.3° GL ethanol, 28.0 g H2O, 0.5 g of Carboxypolymethylene [Carbopol 940® or Carbomer], 5 drops of triethanolamine (pH 5–7), and glycerol (1.5% w/w). The thermal behavior of the ethanol, carbopol, triethanolamine, glycerol, and alcohol gels were evaluated using Thermogravimetry and Differential Thermal Analysis. The apparent viscosity was obtained using a rotary viscometer. The determination of in vitro spreadability was achieved by an adaptation of the Knorst method. The ethanol content was measured by headspace gas chromatography using a flame ionization detector. The thermal behavior of the gels was influenced by the presence of glycerol, which confirms the possible network interactions formed. The relative densities of the samples were between 0.887 and 0.890 g/cm3. No alteration of the pH of the formulation resulted from the incorporation of glycerol. The apparent viscosities of the alcohol gels were greater than 20,000 cP. No alteration in the in vitro spreadability of the gel alcohol (530.6 mm2) resulted from the addition of glycerol. Hand sanitizer was produced using glycerol from a transesterification reaction. It represents an alternative use for the glycerol being produced in biodiesel processes. The product satisfied the requirements of WHO that preconize a formulation containing 1.45% glycerol as an humectant to protect skin against dryness and dermatitis.

Purification of glycerol as a by-product of biodiesel based on palm oil and castor oil

The government program requires the use of biodiesel B35, which is 35% fatty acid methyl ester and 65% diesel oil from petroleum, which would impact the rise of biodiesel production and is accompanied by an increase in the by-product of crude glycerol. Crude glycerol requires purification to increase its selling value. This product still contains a lot of impurities such as methanol, soap, catalyst, fatty acids, and water. Crude glycerol, a by-product of making biodiesel based on palm oil and castor oil, has a purity of 39.10 and 37.30%. In this research, purification of crude glycerol was carried out using 10% w/v activated carbon. The results of glycerol after purification were 64.90 and 66.90%, it shows that the addition of activated carbon can absorb impurities contained in glycerol. The increase in levels from 37.30 to 64.90% and 66.90% due to the loss of water, alcohol, residue base (KOH), soap and fatty acids. It can be concluded that activated carbon is quite effective for the glycerol purification process with an addition of 10% (w/v). A further process is required, namely separation by distillation, to obtain glycerol with a purity above 80% to comply with SNI 7182-2015 standards.

Evaluating the environmental impact of crude glycerol purification derived from biodiesel production: A comparative life cycle assessment study

In recent decades, surplus crude glycerol has been generated in large amounts as a waste product of biodiesel production, leading to bottlenecks in the supply chain of the biodiesel industry. This waste glycerol represents an important potential renewable feedstock and platform chemical; however, its purification is often needed for further processing. Advancements towards glycerol purification are being made using sustainable purification techniques aimed at improving the biodiesel industry's environmental footprint. Many studies focussing on various techniques to purify glycerol can be found in the literature; however, very few studies to evaluate the environmental impacts of the purification processes have been reported. This paper provides a critical investigation on the cradle-to-gate life cycle assessment (LCA) of three different processes for purifying crude glycerol, namely, physicochemical treatment and membrane purification (PMP) processes, vacuum distillation purification (VDP) processes and ion exchange purification (IEP) processes having a functional unit (FU) of 1000 kg of purified glycerol. These purification processes were modelled using Aspen plus software v12.1 in combination with Super Pro Designer v13. CCaLC2 (Carbon Calculations over the Life Cycle of Industrial Activities) was used to measure the environmental impacts associated with each process. By following the ISO 14044:2006 methodology and utilising the CCaLC2 tool, seven different types of potential environmental impacts have been investigated, which include carbon footprint, water footprint, acidification, eutrophication, ozone layer depletion, photochemical smog and human toxicity. Sensitivity analysis of the LCA was carried out using the response surface method (RSM) to determine the most effective parameter within the LCA. The total carbon footprint of the PMP, VDP and IEP processes are 3466.82, 1745.72 and 2239.71 kg CO2 eq. FU−1 respectively. The LCA study determined that waste generated as a result of crude glycerol impurities from the three processes had one of the highest environmental impacts on the overall process. For the PMP and IEP processes, the raw materials used in the physicochemical treatment also contribute significantly to the carbon footprint and other environmental impacts. Lastly, aspects concerning the environmental impacts from the PMP glycerol purification process have been addressed by analysing the raw materials from different sources accompanied by altered waste disposal methods (i.e. the incineration of generated wastes as opposed to landfilling) in an attempt to reduce the overall environmental impacts. For the PMP process, which has the highest carbon footprint, usage of differently sourced raw materials and altered waste disposal treatments resulted in 39% reduction in total carbon footprint and 54% reduction in the total ozone layer depletion. Sensitivity analysis of the LCA shows that the glycerol content within the crude glycerol was the most significant parameter.

Vapor-Liquid Equilibrium Measurement of Systems Containing Glycerol for Separation Process of Glycerol as a By-Product of Biodiesel

The most popular technique to produce biodiesel were uses alcohol as a catalyst to transesterify triglycerides. The biodiesel transesterification process has a by-product in the form of glycerol which has a high selling value. Equilibrium data of glycerol and alcohol mixtures is limited in equilibrium conditions and systems which causes the glycerol purification process may not be designed and operated optimally. This research aims to obtain experimentally isobaric vapor-liquid equilibrium of methanol + glycerol binary system at 31.3, 61.3, and 100.8 kPa. A modified Glass Othmer-Still was utilised to carry out the experiment. Refractometer index type Bausch and Lomb ABBE was used to examine the equilibrium composition of the liquid and vapor phases. Using the L-W thermodynamic consistency test method, the experimental data used in this work were shown to be thermodynamically consistent. The experimental data were correlated well with the Wilson, Non-Random Two Liquid (NRTL), and Universal Quasi-Chemical (UNIQUAC) models with absolute average deviation in temperatures (AADT) and that in vapor compositions (AADy) smaller than 0.3% and 0.2%, respectively. The Universal Chemical Functional Group Activity Coefficient (UNIFAC) in predicting VLE the system studied showed good performance giving AADT and AADy smaller than 7.4% and 0.04%, respectively.

Ultrasonic-assisted synthesis of mono- and diacylglycerols and purification of crude glycerol derived from biodiesel production

Production of monoacylglycerols (MAGs) and diacylglycerols (DAGs) via glycerolysis of fatty acid methyl esters (FAME) with glycerol (G) using an ultrasonic bath and probe was investigated. The glycerolysis using an ultrasonic bath at the optimum condition: KOH 3 wt% of glycerol, ethanol 5.5% v/v solution, and ultrasonic frequency 35 kHz yielded only 3.30% MAGs and 11.47% DAGs because the temperature was limited at 80 °C. The effect of four variables including the molar ratio of G:FAME (2.5:1–3.5:1), KOH (2.5–3.5 wt% of G), time (45–75 min), and temperature (140–160 °C) for glycerolysis utilizing an ultrasonic probe was studied and optimized by response surface methodology (RSM) and box-Behnken design (BBD). The condition: 2.82:1 G:FAME mol:mol, KOH 3.18 wt% of glycerol, 46.33 min, and 155.66 °C was recommended to achieve the highest MAGs (53.32%). To produce the most DAGs, a lower molar ratio, higher temperature, and longer time were suggested. Purification of crude glycerol by a simple multi-step process was proposed and a yield of 45 ± 0.34% was obtained with glycerol purity up to 95%. Glycerolysis of the purified and pure glycerol gave identical contents of MAGs and DAGs. Crystallization was operated to purify MAGs by investigating crystallization temperatures and solvents. Two-step crystallization obtained up to 96% MAG content and the major product was mono-palmitin. The synthesis of MAGs and DAGs was successful through the utilization of an ultrasonic probe, and crystallization was an effective method for MAG purification.

Experimental and Simulation Studies for Purification and Etherification of Glycerol from the Biodiesel Industry

In this study, a purification route was applied to crude glycerol and its valorization via etherification was evaluated. Crude glycerol samples were obtained through transesterification reactions of soybean oil with methanol using potassium hydroxide as catalyst. A set of separation steps (acidification, neutralization, salt precipitation, evaporation and removal of contaminants using ion-exchange resins) was performed for purification of crude glycerol. The glycerol contents of crude samples were 46% wt., and for purified samples they were above 98% wt. The etherification reactions were carried out with purified samples and different alcohols (ethanol, isopropanol and 3-methyl-1-butanol) placed into a batch reactor, using a small amount of Amberlyst 15 as a catalyst, with autogenous pressure and solvent-free conditions. The glycerol conversion, selectivity and yield to ethers were evaluated. A glycerol conversion of up to 97% wt. was obtained when using ethanol. For isopropanol, the glycerol conversion rate was 85% (97.1% of monoether and 2.8% of diether). However, the selectivity to ethers for 3-methyl-1-butanol was negligible (<3% wt.). A process simulation for the purification and etherification steps integrated with a biodiesel production process was assessed in terms of productivity and energy consumption, considering different scenarios of glycerol/alcohol molar ratios. Finally, main impacts on the overall energy consumption were evaluated for the purification processes (glycerol and ethers).

Continuous separation and purification of glycerol distillation residues in the sense of circular economy: Experimental proof-of-concept and techno-economic assessment

The residue obtained in the course of the distillative purification of crude glycerol from biodiesel production contains mainly inorganic salts like sodium chloride and potassium sulphate, glycerol and matter-organic-non-glycerol. This residue is often discarded, since organic matter is present in the salts which prohibits further use where higher salt purities are needed. However, separation and purification of the residue is of interest, from an environmental but also economic point of view. Here, we demonstrate an experimental proof-of-concept for the separation and purification of glycerol-salt mixtures with ethanol as solvent in continuous counter-current solid-liquid operation in a stirred extraction column, the Taylor-Couette disc contactor. The Taylor-Couette disc contactor proves to be a viable apparatus for this application, especially in view of its simple and robust design with absence of static internals, which limits fouling and prevents accumulation of solids. Furthermore, a techno-economic assessment of the process based on a simulation in AspenPlus was conducted. Economics were evaluated on the basis of capital and operating expenditures, also taking into account waste disposal costs and profits from the sale of value-added products such as purified salt.

Optimized conditions for the design and operation of a vacuum distillation column for the purification of crude glycerol from biodiesel production

AbstractDue to the growth in global demand for biodiesel, there is a tendency for the volume of its main by‐product, glycerol, available on the market to increase. This has led to a search for new uses for this by‐product and the development of new processes that use glycerol as a raw material because it has wide industrial applications. However, to be used in many of these processes, the glycerol must go through a purification stage before reaching the purity required for the application (which can reach 99.7% w/w). Taking this into account, the optimization of the parameters for the main glycerol purification stage (vacuum distillation) is essential to reduce the cost of this stage as much as possible. In this article, optimization of the vacuum distillation column was carried out using an artificial neural network (ANN) and a genetic algorithm (GA) together. With the optimization, it was found that four theoretical stages of equilibrium (separation) is the optimal value, in economics terms, for the distillation column on an industrial scale, leading to better performance (in terms of glycerol purity) than patents that used a smaller number of theoretical stages and an equal performance in relation to the patents that used a greater number of stages, which in this case reduces the cost with the size of the column. This result helps to increase the financially viability of using glycerol as a raw material, which can make several processes cheaper, thus generating greater added value to this sustainable by‐product. © 2023 Society of Industrial Chemistry and John Wiley & Sons Ltd.

New trends on crude glycerol purification: A review

The increasing effort of the global community to reduce dependency on fossil fuels led to an increase in the production of biodiesel and therefore the oversupply of crude glycerol. Different steps are necessary to ensure this oversupply of highly impure, waste-based crude glycerol (approximately 680,000 tonnes by 2024) can be made suitable for applications. This review paper aims to give an overview of the recent developments of the global glycerol market and discusses advanced crude glycerol purification technologies (as compared to physio-chemical treatments). The market overview involves information on the relevance of the global glycerol market and the different grades of glycerol which are produced. Additionally, different application areas for glycerol are detailed; including current industrial solutions, challenges, and outlooks. The second part reports newly proposed crude glycerol purification technologies from industry and recent research since 2014, their advantages and disadvantages, and feasibility in terms of industrial implementation at scale. The results of this review suggest that pressure-, thermally- and electrochemically-driven membrane-based separation technologies could solve the issue of expensive large scale vacuum distillation columns lowering capital and operating expenditures reaching > 99 % of glycerol purity. However, the increase of lower quality glycerol generated resulting from 2nd generation bio-diesel plants presents challenges due to the increasing ash and matter organic non-glycerol (MONG) impurities (due to the use of waste-based feedstocks in biodiesel production). As result, hybrid solutions may be needed since advanced purification technologies cannot be used as stand-alone solutions but need to be accompanied by a proper pre-treatment.

Purification of glycerol from biodiesel by-product by using kitchen vinegar

Indonesia is a country that produces large amounts of palm oil. Oil palm plantations are often found in Sumatra and Kalimantan. Palm oil is usually used as a raw material for making cooking oil. Apart from that, it can be used as a raw material for biodiesel production from vegetable oil taken from palm oil. The production of biodiesel from palm cooking oil produces a by-product in the form of glycerol, where the glycerol is still in the form of crude glycerol which cannot be utilized. Glycerol purification is carried out by the method of acidification and evaporation to remove the KOH catalyst and methanol that are still present in the crude glycerol. The acid used was 2 ml of kitchen vinegar and was carried out 3 times. The purpose of this study was to obtain glycerol and water content. The results of this study showed that the highest glycerol content was 83.47%, the lowest water content was 1.83%, the lowest pH was 12.00 and the color of glycerol was blackish brown.

Purification of Residual Glycerol from Biodiesel Production as a Value-Added Raw Material for Glycerolysis of Free Fatty Acids in Waste Cooking Oil

The crude glycerol produced as a byproduct of transesterification synthesis has very few applications because it comprises of significant amounts of methanol, catalyst, and soap. On the other hand, transesterifications of highly acidic oil in the presence of an alkaline catalyst are problematic due to the presence of high amounts of free fatty acids. In this study, the free fatty acid level of high acid oil, which was initially determined to be 19.25%, was decreased to permit the direct production of biodiesel via glycerolysis with pure glycerol, making direct transesterification feasible. Through a process of purification, crude glycerol was refined to 92.5% purity. It was revealed that the physiochemical parameters of density, moisture content, ash content, matter organic non-glycerol content, pH, and Na/K concentrations of generated purified glycerol are equal to those of commercially available glycerol. In contrast, glycerolysis treatment successfully decreased the free fatty acid level to less than 2% under optimal conditions, which were determined to be 200 °C, a glycerol-to-oil molar ratio of 4:1, and a KOH catalyst concentration of 1.6 wt.% at 350 rpm. The inclusion of hexane as a co-solvent accelerated the glycerolysis process, and the weight ratio of oil-to-hexane was 8:1. Moreover, it was viable to use waste methanol for biodiesel synthesis and purified crude glycerol as a raw material in a variety of industries, including biodiesel production. In addition, compared to acid esterification, the FFA concentration of oil with a high acid value fell significantly.

Simultaneous refining of biodiesel-derived crude glycerol and synthesis of value-added powdered catalysts for biodiesel production: A green chemistry approach for sustainable biodiesel industries

Glycerol is one of the industrially important chemicals having a wide range of applications in many fields. One of the important processes to obtain glycerol is during the biodiesel production, where it is formed as a by-product. However, it is crude and needs to be purified. Interestingly, the purification process of glycerol can be versatile, where it is possible to purify the crude glycerol and synthesize value-added chemical simultaneously. In this context, herein, we have developed an acidification-based process and demonstrated the concurrent purification of biodiesel-derived glycerol and the synthesis of sodium sulphate (Na2SO4) and potassium sulphate (K2SO4) as value-added chemicals. . The obtained results reveal that the established process is promising and yields commercial-grade glycerol (with ∼95% purity) along with the value-added chemicals Na2SO4 and K2SO4 with a purity of ∼95 and 98%, respectively. In addition, these synthesized powders have also been utilized as catalyst in biodiesel production with a yield of 96.1 and 94.8%, respectively with 3.5 wt% catalyst concentration. From the kinetic study, which is the pseudo-first order reaction, the activation-energy and frequency-factor for Na2SO4 and K2SO4 are estimated to be 38.27 kJ/mol and 2.2 × 104 min−1 and 44.69 kJ/mol and 2.4 × 105 min−1, respectively. The thermodynamic parameters of enthalpy (ΔH), entropy (ΔS) and Gibbs free energy (ΔG) of Na2SO4 and K2SO4 catalysed process suggested the endothermic, endergonic, and non-spontaneous nature of the reaction. Further, the recovered Na2SO4 and K2SO4 were reused for four times in biodiesel production, which showed a consistent yield of biodiesel in all the four cycles.