Enrique Velo

Pyrolysis of blends of biomass with poor coals

This paper reports on the pyrolytic behaviour of three different kinds of solid fuel and their blends in order to understand and further improve the performance of fluidized bed gasification of biomass-poor coal blends. Individual feedstocks consisting of pine chips, black coal and waste coal and several biomass-coal blends were pyrolysed in a thermobalance apparatus at atmospheric pressure. Experiments were carried out dynamically by increasing the temperature from 110 to 900°C with a heating rate of 100 K min−1. The data show very poor behaviour of the waste coal compared with pine chips and even black coal. Nevertheless, when a minimum of 40% of pine chips was blended with 60% waste coal and pyrolysed under the same conditions, the rate of mass loss increased sharply and was similar to that of black coal. D.t.g. results indicate that the main pyrolysis processes can be quantitatively expressed in terms of C0 = Cwe−kt for both the individual fuels and the blends. Additional studies showed that no interaction takes place between biomass and coal in a blend during pyrolysis.

Thermogravimetric study of the pyrolysis of waste wood

Abstract A thermogravimetric study of the pyrolysis of three different types of waste wood (forest wood, old furniture and used pallets) is carried out in a TGA equipment using dynamic and isothermal techniques. Isothermal runs were carried out at two temperature levels, one between 225° and 325°C (low range) and the other, between 700° and 900°C (high range). Results show a good agreement between the kinetic parameters obtained from either dynamic or isothermal techniques. It must be remarked that the own chemical composition of each type of wood together with the compounds added to the wood for each application, play a fundamental role in the kinetic behavior of their thermal decomposition.

Predicting the minimum fluidization velocity of polydisperse mixtures of scrap-wood particles

Abstract A new relationship for the prediction of the apparent minimum fluidization velocity of polydisperse systems of scrap-wood particles is proposed. This method takes into account the relationship between the shape factor and the bed porosity with the minimum fluidization velocity. The equation proposed by Otero and Corella [A.R. Otero, J. Corella, An. Soc. Esp. Fis. Quim. 67 (1971) 1207.] has been generalized for mixtures with more than two components and then combined with the Ergun equation for the system under study. The hydrodynamic behavior observed for all types of particles corresponds to Geldart C-type powders. The nature of the particle has remarkable influence on such behavior.

Safe storage temperature of peroxide initiators: prediction of self-accelerated decomposition temperature based on a runaway heuristics

Abstract Organic peroxides are slightly stable substances that can self-decompose under favourable conditions. During storage there can be a loss of activity if the temperature is above the recommended storage temperature. At higher temperatures this decomposition is self-accelerating. Many peroxides, are extremely shock sensitive or unstable in pure form and are, therefore, only commercially available in diluted solution. In this work, the thermal stability of 44 compounds is evaluated. The method suggested here for predicting the self-accelerating decomposition temperature (SADT) is based on the numerical solution of the equations derived from the mass and energy balances coupled to a heuristics to recognise parameter sets that produce runaway.

Optimizing microwind rural electrification projects. A case study in Peru

Electrification systems based on the use of renewable energy sources are suitable for providing electricity to isolated communities autonomously. Specifically, electrification by wind power is one of the technological options that have been used recently in projects implemented in the Andean highlands of Peru. To date, these projects have tended to install individual microwind turbines at each demand point. Alternatively, we propose a solution that considers both individual generators and microgrids. We develop a mathematical model that gives the location and size or type of the wind turbines and the design of the microgrids, taking into account the demand of the consumption points and the wind potential. The criterion is the minimization of the initial investment cost required to meet the demand. The model is validated by application to a real case in the northern highlands of Peru. Results show that microgrids are used despite the village dispersion, and the solutions significantly reduce the initial investment costs.

Identification of a pilot scale fluidised-bed coal gasification unit by using neural networks

This work is under the general framework of advanced control system application to a pilot scale gasification reactor. In this paper the identification step of the system and the dynamic analysis have been studied. For system identification the artificial neural network (ANN) has been used and an ANN model was developed.

How Do Energy Engineers of the Future Think. Analysis of Master Students’ Proposals

The future of energy largely depends on the creativity and innovation capacity of energy engineers. Projects on renewable energy developed by master’s students can be significant to know the vision of the new generation of energy engineers. The projects of 168 international students pursuing EIT KIC InnoEnergy masters, more specifically MSc RENE and MSc SELECT, were analysed. The students were gathered in 25 teams and worked on projects and challenges following their own ideas. The students’ proposals were listed and classified according to technologies, degree of radical innovation, complexity, scope, TRL and agents that would develop the solutions. The typical proposal is based on solar energy, involves several elements, has, at least initially, a limited scope, uses commercially available technology, and is adapted to the case in all other respects. This vision seems to be very promising to spread renewable energy solutions.

Active learning in sustainable energy master degrees: A multiple challenge approach

The analysis presented here starts from the experience in challenge-based education developed in the master degrees MSc RENE and MSc SELECT. These MSc programs are offered by InnoEnergy partner universities, funded by the EU through the European Institute of Innovation and Technology (EIT). We analyse how a total 32 challenges addressed by the students take into account a list of 9 competences and characteristics of the projects and the diversity of the own characteristics and the solutions adopted. Our final objective is to test the effectiveness of the development by the students of a diversity ofprojects. We concluded that, as expected, most of the competences and other characteristics of the projects as market approach are addressed. The diversity of characteristics and solutions adopted is high in relation with technologies, innovation and entrepreneurship we can observe a considerable diversity. Social commitment and connection with the industry are less involved that expected with the levels of development and again the connection with the industry are scarcely diversified. In spite of this, we think that the multiple-challenge approach is effective in developing a diversity of competences in the different areas involved We also observe that because of the open character of these activities the control and management of the competences developed is not immediate. As a future suggestion we propose to extend the use of the multiple-challenge approach in sustainable energy programs and the development of a systematic monitoring of the kind of challenges addressed and the competences developed by each student.