Biodiesel Production & Biodiesel Conversion
When you make biodiesel, slow reaction kinetics and poor mass transfer are lowering your biodiesel plant capacity as well as your biodiesel yield and quality. Hielscher ultrasonic reactors improve the transesterification kinetics significantly. Therefore lower excess methanol and less catalyst are required for biodiesel processing.
Biodiesel is commonly produced in batch reactors using heat and mechanical mixing as energy input. Ultrasonic cavitational mixing is an effective alternative to achieve a better mixing in commercial biodiesel processing. Ultrasonic cavitation provides the necessary activation energy for the industrial biodiesel transesterification.
Ultrasonic mixing improves biodiesel conversion rate, increases yield and saves excess methanol and catalyst.
Ultrasonically Improved Transesterification of Biodiesel
Biodiesel production typically involves a chemical reaction called transesterification, in which a triglyceride (such as vegetable oil, animal fat, spent cooking oils) reacts with an alcohol (such as methanol) in the presence of a catalyst to produce biodiesel (fatty acid methyl esters) and glycerol. Ultrasonic reactors can be used to enhance the transesterification process in several ways, leading to several benefits:
- Improved mixing: Ultrasonic waves can create cavitation bubbles that collapse violently, causing intense mixing and agitation of the reaction mixture. This leads to better contact between the reactants and the catalyst, resulting in faster and more complete transesterification.
- Accelerated reaction kinetics: The high-energy conditions generated by ultrasonic waves can activate the reaction, increasing the reaction rate and reducing the reaction time needed to reach a given level of conversion. This can result in higher yields and lower costs.
- Reduced catalyst usage: Ultrasonic reactors can improve the efficiency of catalyst use by providing more active sites for the reaction. This means that less catalyst is required to achieve the same level of conversion, reducing costs and environmental impact.
- Improved product quality: Ultrasonic reactors can produce biodiesel with lower free fatty acid content, higher purity, and better cold flow properties. This is due to the improved mixing and faster reaction kinetics, which minimize the formation of unwanted byproducts and impurities.
These advantages of ultrasonic biodiesel processing make the use of an ultrasound reactor setup highly economical since the use of ultrasonic reactors significantly improves the efficiency, speed, and quality of biodiesel transesterification. This means in summary that ultrasonication turns the transesterification into a more economically and environmentally sustainable process.
Problems of Conventional Biodiesel Mixing: The conventional esterification reaction in batch processing tends to be slow, and phase separation of the glycerin is time-consuming, often taking 5 hours or more.
Ultrasonic reactors help you to accelerate your biodiesel process and simultaneously increase your biodiesel yield and quality at lower processing costs!
Industrial-grade ultrasonicator UIP2000hdT with flow cell FC2T500k for inline biodiesel esterfication and transesterification.
The Advantages of Ultrasonic Biodiesel Transesterification
- Higher biodiesel yields due to improved mixing
- Increased biodiesel quality
- Use even poorest oil as feedstock
- Continuous inline processing
- Less methanol
- Less catalyst
- Time-saving due to high-speed conversion
- Energy-saving
- Simple and safe operation
- Robustness and low maintenance
- High performance: 24/7 operation under full load
“We’ve been very pleased with Hielscher’s equipment and service and we have every intention of including the Hielscher ultrasonication technology in all of our future endeavors.”
Todd Stephens, Tulsa Biofuels
Ultrasonics for Biodiesel Production
Biodiesel is often produced in batch reactors. Ultrasonic biodiesel conversion allows for the continuous inline processing. Ultrasonication can achieve a biodiesel yield in excess of 99%. Ultrasonic reactors reduce the processing time from the conventional 1 to 4 hour batch processing to less than 30 seconds. More important, ultrasonication reduces the separation time from 5 to 10 hours (using conventional agitation) to less than 60 minutes. The ultrasonication does also help to decrease to amount of catalyst required by up to 50% due to the increased chemical activity in the presence of cavitation. When using ultrasonication the amount of excess methanol required is reduced, too. Another benefit is the resulting increase in the purity of the glycerin.
Ultrasonic Biodiesel Production Step-by-Step:
- the vegetable oil or animal fat is being mixed with the methanol (which makes methyl esters) or ethanol (for ethyl esters) and sodium or potassium methoxide or hydroxide
- the mix is heated, e.g. to temperatures between 45 and 65degC
- the heated mix is being sonicated inline for 5 to 15 seconds
- glycerin drops out or is separated using centrifuges
- the converted biodiesel is washed with water
Most commonly, the sonication is performed at an elevated pressure (1 to 3bar, gauge pressure) using a feed pump and an adjustable back-pressure valve next to the flow cell.
Industrial biodiesel conversion does not need much ultrasonic energy. The actual energy requirement can be determined at benchtop scale using e.g., a 1kW ultrasonic processor such as the UIP1000hdT. All results from such bench-top trials can be scaled up linear and without any problems. If required, ATEX-certified ultrasonic devices are available, such as the UIP1000-Exd.
Hielscher supplies industrial ultrasonic biodiesel processing equipment, worldwide. With ultrasonic processors of up to 16kW power per single device, there is no limit in biodiesel plant size or processing capacity.
Costs of Ultrasonic Biodiesel Manufacturing
Ultrasonication is an effective means to increase the reaction speed and conversion rate in the commercial biodiesel production. Ultrasonic processing costs result mainly from the investment for ultrasonic equipment, utility costs and maintenance. The outstanding energy efficiency of Hielscher ultrasonicators helps to reduce the utility costs and by this to make this process even greener. The resulting costs for the ultrasonication vary between 0.1ct and 1.0ct per liter (0.4ct to 1.9ct/gallon) when used on commercial scale.
Read more about the process efficiency and economical benefits of ultrasonic biodiesel production!
Ultrasonic mixing reduces the specific energy consumption inbiodiesel manufacturing outperformin hydrodynamic magnetic mixing and high-shear mixers by far.
Small Scale Ultrasonic Biodiesel Setup
Ultrasonication can be used for the conversion of oil into biodiesel at any scale. The picture below shows a small scale setup for the processing of 60-70L (16 to 19 gallons). This is the typical setup for initial studies and process demonstration.
Ultrasonic esterification and transesterification can be run as batch or continuous inline process. This chart shows the ultrasonic batch process for biodiesel conversion.
3x 1kW ultrasonicators of the model 1000hdT with ultrasonic flow-through reactor with for highly efficient biodiesel conversion.
- one ultrasonicator (e.g., UIP500hdT or UIP1000hdT) with booster, sonotrode and flow cell
- power meter for metering power and energy
- 80L processing tank (plastic, e.g. HDPE)
- heating element (1 to 2kW)
- 10L catalyst premix tank (plastic, e.g. HDPE)
- catalyst premixer (stirrer)
- pump (centrifuge, mono or gear) for approx. 10 to 20L/min at 1 to 3 barg
- back-pressure valve for adjusting pressure in the flow cell
- pressure gauge for measuring feed pressure
Ultrasonic Reactors for Superior Biodiesel Processing
Hielscher Ultrasonics offers high-performance ultrasonic processors and reactors, which will improve your biodiesel production by higher biodiesel yields, improved biodiesel quality, reduced processing time and lower production costs.
Small and Medium Scale Ultrasonic Reactors for Biodiesel Transesterification
For small and medium size biodiesel production of up to 9ton/hr (2900 gal/hr), Hielscher offers you the UIP500hdT (500 watts), UIP1000hdT (1000 watts), UIP1500hdT (1500 watts), and UIP2000hdT (2000 watts) as ultrasonic high-shear mixers with flow-through reactors for reliable and efficient inline biodiesel processing. These four ultrasonic reactors are very compact, easy to integrate or retro-fit. They are built for heavy duty operation in harsh environments. Below you will find recommended reactor setups for a range of production rates.
|
ton/hr
|
gal/hr
|
|
|---|---|---|
| 1x UIP500hdT (500 watts) |
0.25 to 0.5
|
80 to 160
|
| 1x UIP1000hdT (1000 watts) |
0.5 to 1.0
|
160 to 320
|
| 1x UIP1500hdT (1500 watts) |
0.75 to 1.5
|
240 to 480
|
| 1x UIP2000hdT (2000 watts) |
1.0 to 2.0
|
320 to 640
|
| 2x UIP2000hdT (2000 watts) |
2.0 to 4.0
|
640 to 1280
|
| 4xUIP1500hdT (1500 watts) |
3.0 to 6.0
|
960 to 1920
|
| 6x UIP1500hdT (1500 watts) |
4.5 to 9.0
|
1440 to 2880
|
| 6x UIP2000hdT (2000 watts) |
6.0 to 12.0
|
1920 to 3840
|
Very Large-Throughput Industrial Biodiesel Reactors
For industrial processing biodiesel production plants Hielscher offers the UIP4000hdT (4kW), UIP6000hdT (6kW), 10000 (10kW), and UIP16000hdT (16kW) ultrasonic homogenizers! These ultrasonic processors are designed for the continuous processing of high flow rates. The UIP4000hdT, UIP6000hdT and UIP10000 can be integrated into standard sea freight containers. Alternatively, all four processor models are available in stainless steel cabinets. An upright installation requires minimal space. Below you find recommended setups for typical industrial processing rates.
|
ton/hr
|
gal/hr
|
1x UIP6000hdT (6000 watts) |
3.0 to 6.0
|
960 to 1920
|
|---|---|---|
| 3x UIP4000hdT (4000 watts) |
6.0 to 12.0
|
1920 to 3840
|
| 5x UIP4000hdT (4000 watts) |
10.0 to 20.0
|
3200 to 6400
|
3x UIP6000hdT (6000 watts) |
9.0 to 18.0
|
2880 to 5880
|
| 3x UIP10000 (10,000 watts) |
15.0 to 30.0
|
4800 to 9600
|
| 3x UIP16000hdT (16,000 watts) |
24.0 to 48.0
|
7680 to 15360
|
| 5x UIP16000hdT |
40.0 to 80.0
|
12800 to 25600
|
Contact Us! / Ask Us!
The ultrasonicator UIP16000hdT is capable to process 32MMGY biodiesel.
Frost & Sullivan Technology Innovation of the Year
Hielscher Ultrasonics received the prestigious Frost and Sullivan Technology Innovation of the Year Award in recognition of the company’s development of novel ultrasonics technology for bio-diesel production.
Click here to read more about the Frost and Sullivan Award for Hielscher Ultrasonics biodiesel reactors!
Transesterification – The Chemical Conversion of Biodiesel
Manufacturing biodiesel from vegetable oils (e.g. soy, canola, jatropha, sunflower seed), algae, animal fats as well as waste cooking oils, involves the base-catalyzed transesterification of fatty acids with methanol or ethanol to give the corresponding methyl esters or ethyl esters. Glycerin is an inevitable byproduct of this reaction.
Vegetable oils as animal fats are triglycerides composed of three chains of fatty acids bound by a glycerin molecule. Triglycerides are esters. Esters are acids, like fatty acids, combined with an alcohol. Glycerine (= glycerol) is a heavy alcohol. In the conversion process triglyceride esters are turned into alkyl esters (= biodiesel) using a catalyst (lye) and an alcohol reagent, e.g. methanol, which yields methyl esters biodiesel. The methanol replaces the glycerin. This chemical conversion process is called transesterification.
After transesterification, the glycerine, which is the heavier phase, will sink to the bottom. Biodiesel, which is the lighter phase, floats on top and can be separated, e.g. by decanters or centrifuges.
Biodiesel Preparation
Potassium Hydroxide (0.2 to 0.4kg, catalyst) is being dissolved into approx. 8.5L Methanol in the catalyst pre-mix tank. This requires stirring of the catalyst premix. The processing tank is being filled with 66L vegetable oil. The oil is being heated by the heating element to 45 to 65degC.
Biodiesel Conversion
When the catalyst is fully dissolved into the Methanol, the catalyst premix is mixed with the heated oil. The pump feeds the mixture to the flow cell. By means of the back-pressure valve, the pressure is adjusted to 1 to 3barg (15 to 45psig). Recirculation through the ultrasonic biodiesel reactor should performed for approx. 20 minutes. During this time, the oil is being converted into biodiesel. After this, the pump and the ultrasound are switched off. The glycerin (heavier phase) will separate from the biodiesel (lighter phase). The separation takes approx. 30 to 60 minutes. When the separation is finished, the glycerin can be drained.
Biodiesel Washing
As the converted biodiesel contains impurities, washing is required. For the washing, water is mixed into the biodiesel. Ultrasonication can benefit the mixing of the biodiesel with the water. This increases the active surface area as a result of the droplet size reduction. Please consider, that very intense sonication may reduce the water droplets to a size, that an almost stable emulsion is being formed that will require special means (e.g. centrifuge) to be separated.
Biodiesel Manufacturing Plant
The flow-chart below shows a typical setup for the in-line sonication of oil, methanol and catalyst for the conversion into biodiesel.
Ultrasonic esterification and transesterification can be run as batch or continuous inline process. The chart shows the ultrasonic inline process for biodiesel (FAME) transesterfication.
Continuous Biodiesel Processing and Separation
In a setup for the continuous biodiesel processing and continuous separation, the heated oil and the catalyst premix are mixed together continuously using adjustable pumps. An inline static mixer improves the homogeneity of the feed to the ultrasonic reactor. The oil/catalyst mixture passes the flow cell, where it is being exposed to ultrasonic cavitation for approx. 5 to 30 seconds. A back-pressure valve is used to control the pressure in the flow cell. The sonicated mix enters the reactor column on the top. The volume of the reactor column is designed to give approx. 1 hour retention time in the column. During that time, the transesterification reaction is completed. The reacted glycerin/biodiesel mix is pumped to the centrifuge where it is separated into the biodiesel and glycerin fractions. Post-processing involves methanol recovery, washing and drying and can be done continuously, too.
This setup eliminates biodiesel reactor batches, conventional agitators and large separator tanks.
Biodiesel Transesterification Reaction Speed
The diagrams below show typical results of the transesterification of rapeseed oil (industrial grade) with sodium methoxide (left) and potassium hydroxide (right). For both tests, a control sample (blue line) was exposed to intense mechanical mixing. The red line represents the sonicated sample of the identical formulation with respect to volume ratio, catalyst concentration and temperature. The horizontal axis shows the time after mixing or sonication, respectively. The vertical axis shows the volume of glycerin that settled at the bottom. This is a simple means of measuring the reaction speed. In both diagrams, the sonicated sample (red) reacts much faster than the control sample (blue).
Comparison of ultrasonic (red graph) vs conventional mixing (blue graph) for biodiesel production – using with sodium methoxide (left) and potassium hydroxide (right) as catalysts.
Links for Biodiesel Supplies
Click here for links to suppliers of pumps and tanks for the biodiesel industry.
Chemical and Safety Information
Please read the information below carefully, to prevent complications and adverse health effects.
Biodiesel Chemicals
Methanol is toxic. It can cause nerve deterioration as a result of prolonged usage. It can be adsorbed by the skin, too. If splashed into eyes it may cause blindness and Methanol can be fatal when swallowed. For this reason, take the necessary precautions when handling Methanol. It is recommended to use a good respirator, an apron and rubber gloves.
Potassium hydroxide (KOH) is toxic and causes skin burn upon contact. Good ventilation is required.
Make sure the workspace is generously and thoroughly ventilated to allow fumes to escape. Vapor cartridge respirators are not effective against methanol fumes. A supplied-air system (SCBA — Self-Contained Breathing Apparatus) gives better protection against methanol vapors.
Biodiesel and Rubber Parts
Running on 100% biodiesel for longer time may cause complications to wetted rubber parts (pump, hoses, O-rings) of the engine. Replacement by steel parts or heavy duty rubber can eliminate this problem. Alternatively you can mix approx. 25% conventional (fossil) diesel into your biodiesel to prevent complications.
Literature / References
- Ali Gholami, Fathollah Pourfayaz, Akbar Maleki (2021): Techno-economic assessment of biodiesel production from canola oil through ultrasonic cavitation. Energy Reports, Volume 7, 2021. 266-277.
- Abdullah, C. S.; Baluch, Nazim; Mohtar, Shahimi (2015): Ascendancy of ultrasonic reactor for micro biodiesel production. Jurnal Teknologi 77, 2015.
- Ramachandran, K.; Suganya, T.; Nagendra Gandhi, N.; Renganathan, S.(2013): Recent developments for biodiesel production by ultrasonic assist transesterification using different heterogeneous catalyst: A review. Renewable and Sustainable Energy Reviews, Volume 22, 2013. 410-418.
- Shinde, Kiran; Serge Kaliaguine (2019): A Comparative Study of Ultrasound Biodiesel Production Using Different Homogeneous Catalysts. ChemEngineering 3, No. 1: 18; 2019.
- Leonardo S.G. Teixeira, Júlio C.R. Assis, Daniel R. Mendonça, Iran T.V. Santos, Paulo R.B. Guimarães, Luiz A.M. Pontes, Josanaide S.R. Teixeira (2009): Comparison between conventional and ultrasonic preparation of beef tallow biodiesel. Fuel Processing Technology, Volume 90, Issue 9, 2009. 1164-1166.
- Hamed Mootabadi, Babak Salamatinia, Subhash Bhatia, Ahmad Zuhairi Abdullah (2010): Ultrasonic-assisted biodiesel production process from palm oil using alkaline earth metal oxides as the heterogeneous catalysts. Fuel, Volume 89, Issue 8; 2010. 1818-1825.
Hielscher Ultrasonics manufactures high-performance ultrasonic homogenizers from lab to industrial size.