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Low cost biodiesel production based on E90h (hydrous ethanol)

Verification of the DUOBIO Process

(A low-cost way to manufacture biodiesel in developing countries)

Ger Janssen, Eindhoven – november 2010

1. Background

The DUOBIO process for the production of Biodiesel from vegetable oils has been described briefly in a USA Patent Application and the subsequent Patent, which was granted in August 2010.

The DUOBIO process is interesting because it provides a relatively simple, relatively cheap, continuous way of manufacturing biodiesel using aqueous ethanol and any vegetable oil. This could be of great value to developing countries where hydrous ethanol is frequently produced and (waste) vegetable oil is readily available.

In the patent application, it is stated that the reaction time of the first step, the hydrolysis of the vegetable oil, takes about 2.5 seconds at 60 ºC. and atmospheric pressure and using a column of 1 m. length. Further details are scarce. It may be assumed that the column used for the second step, the esterification process, is also 1 m. length. Reaction-time and –temperature are not stated.

It would be interesting to obtain more process details and parameters by actually building a biodiesel reactor, according to the DUOBIO description and to gather experimental data. If the results are promising, FACT intends to consider the construction of a small scale, low cost

production unit.

2. Description of the proposed set-up and the process.

A vegetable oil is finely emulsified with water and heated to a temperature of 60 ºC. The emulsion is introduced at the top of a column (e.g. with a length of 1 m. and a diameter of 10 cm.). The column is filled with CaO.MgO (dolomite) stones, with a max size of approximately 6 mm.

The resulting reaction mixture, consisting of a fatty acid fraction and a water-glycerol fraction, is collected at the bottom of the column and allowed to separate by gravity.

The fatty acid fraction is then mixed with aqueous ethanol in a 1:2 molar ratio and introduced at the top of the second column. This column is identical to the first column and also filled with CaO.MgO stones. The optimal reaction temperature needs to be determined. The reaction mixture is collected at the bottom of the second column and allowed to separate by gravity. One fraction is the fatty acid-ethyl ester dissolved in ethanol. The other fraction consists of process water.

The ethanol-ethyl ester is collected and subjected to a fractionated distillation to yield the ethyl ester (biodiesel) and aqueous ethanol. This ethanol can be re-used for the second process step. 

3. Research questions

Initially, the process could be operated as a batch process, but the objective would be to design a continuous process.

For this purpose, and for the optimization of the process, a number of process parameters and variables have to be determined.

Important questions to be answered are:

• Does the process work as described in the patent
• What are the advantages and disadvantages
• Are there ways to eliminate disadvantages
• Is it feasible to operate with a continuous process
• What is the operational life time of the catalyst
• Is periodic regeneration of the catalyst required
• If regeneration and/or cleaning is needed, which procedure should be used
• What is the overall yield and efficiency of the process
• Is the process economically feasible

To obtain an answer on several of the above questions, the overall mass balance of the process will have to be investigated in terms of the input to the process (vegetable oil and aqueous ethanol) versus the output (aqueous glycerol, biodiesel and possibly other products).

4. Facilities

In cooperation with the businesses and universities (TU/e, WUR), FACT will provide access to a laboratory to carry out experiments. FACT will also provide the necessary equipment, materials and reagents and will make arrangements  to have reaction products chemically analyzed.

In addition, FACT will provide guidance of the student(s)  by a senior chemical engineer.

5. Qualification

It is envisaged that students interested to become involved in this project would need to have a basic (2-3 year) chemical education and also need to have practical experience with carrying out experiments in a chemical laboratory.

6. Contact

Ir. Ger Janssen.

FACT Foundation.

Ir. Ywe Jan Franken

FACT Foundation