From left to right: Andrés Barrera, student of the Chemical Engineering Academic Program; David Gómez-Ríos, professor and director of Chemical Engineering; Howard Ramírez Malule, professor and Director of the BIOQUIMAP Research Group. Credit: Édgar Bejarano, Communications Office, Faculty of Engineering.
As a result
of his undergraduate work, Andrés Barrera, from Chemical Engineering program at
the Universidad del Valle, developed a low-cost system to measure hydrogen
emissions produced from the treatment of sugarcane waste that seeks to be
useful for small producers in non-interconnected regions of the country. Being
a rare milestone among undergraduate students, the result of his work was
published in the international journal AgriEngineering, classified as Q1 in the
SJR bibliographic index and dedicated to make visible innovative technologies
in the field of agriculture in the world.
The search for other uses
It all started when Andrés Barrera shared with his professors his interest in working in biological processes derived from the reuse of materials considered waste, after being used in large-scale industrial activities. Among the options they considered, the one that most caught their attention was the one about developing a bioreactor that transforms the waste produced in Valle del Cauca into a source of energy. They decided to work with sugarcane vinasse and AHR –Agricultural Harvest Residues- because of the danger that could be caused to water sources, added to the current regulations on their use, have brought with them the big question about their subsequent uses.
After a long period of research, the idea was to convert waste into an energy vector that could contribute to the search for clean energy, within the framework of the global energy transition, as well as a future for income generation for small and large producers. Instead of methane, the form of energy usually generated from waste, Andrés turned it to hydrogen.
“It is something that has much greater potential in terms of capacity and in terms of the hydrogen route. Because in the country there is already a hydrogen route that tells us that Colombia wants to make that transition from fossil fuel to hydrogen,” says Andrés, adding that for this research the dark fermentation method was used.
Hydrogen production was, then, their starting point. They did all the research, agreed on what to do with the raw material, what kinds of pretreatments to do with it. It was not easy to work with these materials. On the one hand, the AHR, composed of dry leaves and similar residues –and which is usually burned, used as cattle feed or for land improvement- has a very rigid structure, so it had to be cracked to bring out its sugars, through diluted acid. On the contrary, the vinasse, being in such concentration in the region, had to go under a treatment that allowed both the existence of sufficient anaerobic bacteria to obtain the hydrogen, together with the carbohydrates and nutrients essential for the dark fermentation process.
MQ-8 sensor: low-cost measurement
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| Student Andrés Barrera explaining the operation of the developed measuring device. Credit: Édgar Bejarano, Communications Office, Faculty of Engineering. |
The next question posed by the experiment was how to measure the information obtained, and for it to be reliable and low-cost. Although there were known options for these measurements in the academy, being gas chromatography the most used for its infallible results, they preferred to look for others, since it requires large economic investments, which leaves aside an important sector of producers in non-interconnected areas of the country.
“Then Andrés, in his literature review, found that there were some very low-cost sensors that could be implemented. He set out the task of getting it and configuring it,” says David Gómez-Ríos, Professor, Director of the School of Chemical Engineering, and director of the degree project. It was an MQ-8 sensor, a meter with an electrical conductivity that increases proportionally to the concentration of hydrogen in the air increases, due to its high sensitivity for this type of gas, which allows valuable information to be captured, even though hydrogen is a very light gas that can easily leak.
The sensor was connected, on one side, to a container where the vinasse and the AHR were, and on the other one to a small Arduino board, which sent the data obtained to a computer in real time, for analysis. Once implemented, the whole experimental process was carried out with different concentrations of vinasse and AHR over six days.
Another of the benefits brought about this technology was the multiple areas in which it can be applied, not only for sugarcane and its derivates but also for other kinds of residues. “If you go to de Cundinamarca-Boyacá highlands, there may be potato residues. If you go to La Guajira there will be residues of other kinds (produced by agriculture activities). If you go to Putumayo, you’ll find the same situation. The same approach we used here with the vinasse can be applied in those places,” clarifies Professor Howard Ramírez Malule, Director of the BIOQUIMAP Research Group and director of Andrés work.
All the above are examples of the need to facilitate waste reuse processes, which also resonate with the desire for energy transition the world is currently trying to implement. According to Professor Gómez-Ríos, such transition implies a series of challenges, among them logistical, which entails certain responsibilities. “We must think about what we do, at the side of generation of a particular waste, so that this technology can be implemented there, without forcing the transportation of large numbers of substances.” Decentralizing the use of these technologies with in-site measurements that this device allows facilitates the use of farmers and small producers so that they can take charge of their productive waste. In this sense, and thanks to the fact that its cost in the market is below 12.000 pesos, the use of this sensor aims, in turn, to encourage the energy transition through more affordable paths, for all types of producers, regardless of where they are located.
Publication of research in the journal AgriEngineering: a milestone for David
The cases of undergraduate students who publish in a scientific journal at an international level are rare. In the case of Andrés Barrera, the idea arose when, during research analysis of the experimentation, they realized that the problems they had found when opting for a low-cost technology could also occur in other cases. In such scenario, they thought, the academic community could value the solution they had arrived at.
“Then, seeing the potential that the work had, in which a development was made and its information was validated, in this case in a smaller scale environment, we decided to look for a journal that was specialize,” recalls Professor Gómez-Ríos, adding that the scientific article was the work of Andrés, who faced the challenges of writing in another language, in addition to the statistical validation that accompanied the results.
After the article was submitted, then, after a short evaluation period, it received the respective feedback. “That also speaks, in a way, that the work was well received,” says Professor Gómez-Ríos.
For Andrés Barrera, the publication of the article was a great happiness. “Because you know that all the effort made over the course of a year is reflected. I liked what I did. I liked everything that was experienced. Despite the challenges and the inconveniences that there were, it was very pleasing for my professional course.” His medium-term objective is, according to him, to pursue a master's degree, which will allow him to continue expanding his knowledge in the bioprocess research study line.
Future improvements
“We are always thinking about low-cost materials. Thinking about the farmer who has waste, but not the technology to use it,” says Professor Howard Ramírez Malule. With these communities in mind, improvements to the hydrogen detection device have been proposed, ranging from the sophistication of its assembly, through a more accurate quantification of the data yielded, the calibration of the sensor, determining its useful lifetime, to the possibility of it becoming a bioreactor to produce both hydrogen and methane.
Such
improvements require investors which could see the potential of this type of
work, something that is already beginning to predict well for the future. “When
we made the disclosure of Andrés´s work (in AgriEngineering), a person from
Cenicaña wrote to me, telling us that what we are doing is very interesting,”
recalls Professor Ramírez, and adds that after that contact they set about the
task of exchanging information, hoping that this could materialize with a joint
work. “We believe that we can take this work to a second stage, on a pilot
scale, not only to remain laboratory research, but also to have a face-to-face
approach with the industry”, are his words.
If interested in being in touch with the student and professors or any further information about the scientific article published, please write the Faculty of Engineering Communications Office: comunicaingenieria@correounivalle.edu.co
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