One of the fastest growing areas of usage of such ultra sonic devices is in the transesterification of oil to biodiesel

Hielscher offer ultrasonic mixing reactors for the production of biodiesel at any scale. The ultrasonic mixing improves mass transfer and reaction kinetics leading to faster transesterification and higher yield. It also reduces catalyst and methanol requirements.

Fig 1. A typical Bio-diesel production

A conventional transesterification reaction in traditional bio-diesel batch processing such as in Fig. 1 tends to be slow, and phase separation of the glycerin is time-consuming, often taking five hours or more. Ultrasonication significantly increases the chemical reaction speed and yield of the transesterification process of vegetable oils and animal fats into biodiesel. This affords the opportunity of switching the production from a time consuming batch processing to a much more rapid continuous flow processing and also reduces investment and operational costs.

Improving this process with Hielscher ultrasonication devices.

The manufacturing of biodiesel from vegetable oils or animal fats, involves the base-catalyzed transesterification of fatty acids with methanol or ethanol to give the corresponding methyl esters or ethyl esters respectively. Ultrasonication can achieve a biodiesel yield in excess of 99%. Ultrasound reduces the processing time and the separation time significantly.

Fig 2. Use of ultrasonic technology in bio-fuel production

Excess methanol and catalyst are significant cost factors in biodiesel production. Hielscher ultrasonic reactors add cavitational shear to the mixing process. This produces much smaller methanol droplets resulting in improved methanol and catalyst utilization. Consequently, less methanol and catalyst are required. In addition to that, the cavitation influences the reaction kinetics, leading to faster and more complete transesterification.

Fig 3. More efficient dispersal of methanol droplets

What are the overall benefits? Quantify them please! And how would my production process change?

• Ultrasonic reactors reduce the processing time from a conventional 1 to 4 hour batch processing time to less than 30 seconds!
• More importantly, ultrasonication reduces the separation time from 5 to 10 hours (using conventional agitation) to less than 60 minutes!
• Ultrasonication also helps to decrease to amount of catalyst required by up to 50%
• When using ultrasonication the amount of excess methanol required is reduced.

An Ultrasonic processing of biodiesel involves the following steps:

1. 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
2. the mix is heated, e.g. to temperatures between 45 and 65degC
3. the heated mix is being sonicated inline for 5 to 15 seconds
4. glycerin drops out or is separated using centrifuges
5. the converted biodiesel is washed with water

Click here to read more about ultrasonics and biodiesel processing efficiency.

Analysis of your final product?

Once you have produced your biodiesel, you will want to examine it before you use it in your engine. There are a number of test you may which to conduct including:

• Calorific Value (CV). This is the measurement of how much energy your fuel holds in terms of MJ/Kg (Mega Joules per Kilogram). This is crucial to the power output of any engine running on your fuel. If you can refine your process to produce fuels with a higher CV, then the efficiency of your engine and power output will also improve! This is essential for anyone thinking about producing biodiesel. We stock a range of calorimeters for measuring CV. Please click here to see our calorimeter homepage.

Please add any comments as to other instruments you think would be useful to link here that fit in with Scimeds portfolio.