The temperature gradient of cereals as an optimization parameter of the milling process in hammermills

The wear degree of knives in hammermills strongly influences electricity consumption, productivity, and total operating costs. Currently, the timely replacement of the knives set is decided based on visual inspections, a feedstock load or a lifespan defined, the electric demand of the mill as compared to the limit of the motor driving it, or the vibrations of the hammermill. These approaches present different shortcomings. This study proposes the temperature gradient of the feedstock during the milling process as an indicator to monitor the wear degree of knives. The temperature gradient was implemented in a hammermill milling maize to compare two operating modes. In the conventional operating mode, the knives set mills with one edge during its lifespan, replacing the set once the electricity demand approaches the limit capacity of the electric motor driving the mill, or until the vibrations increase over safety limits. Moreover, in the proposed operating mode the temperature gradient is used to define the timely replacement/rotation of the knives edge. In this case, the four edges of the knives are used. The electricity consumption, productivity, and temperature gradient of the process were measured during the milling of ten maize loads of 2500 tons each. These data were used to characterize the performance of the hammermill, and the influence of the temperature gradient on its operational performance. As a result, a temperature gradient of 6.5 °C was defined as the optimal value to change the rotational direction or replacing the knives set in the hammermill assessed. As compared to the traditional operation approach, the use of the temperature gradient resulted in a reduction of the electricity consumption of 32%, and the greenhouse gas emissions by 37%, while reducing the total costs by 33%, and increasing productivity by 20%. Therefore, this approach stands as a significant opportunity to upgrade the operation of hammermills

Caso Cuba. Un camino al desarrollo sostenible.

En el trabajo analiza el modelo cubano de desarrollo sostenible y se explican las causas de que sea el único país del mundo que según el World Wide Fund for Nature cumpla con los requisitos para ser sostenible. Se exponen los resultados alcanzados en la educación y la salud que explican los altos resultados del Indice de Desarrollo Humano (IDH) y se analiza la Huella Ecológica (HE) del país y las políticas que se han aplicado en sus dos componentes fundamentales, la huella de carbono y la de las tierras cultivables. Que han permitido una recuperación económica sin incrementos notables de la huella ecológica

Evaluación de producción más limpia en la empresa productora de Piensos Cienfuegos

En el trabajo se realizara una Evaluación de Producción Más Limpia en la Empresa Productora de Piensos Cienfuegos. Se realizó un estudio detallado de las entradas y salidas del proceso, para identificar las opciones de mejoras e implementar un Plan de Producción Más Limpia. Se propone un plan de medidas, al cual previamente se le ha fundamentado su factibilidad técnica y económica, que incluye acciones de aplicación inmediata que proponen aplicar buenas prácticas operativas para el uso eficiente de las materias primas, otras que requieren cambios tecnológicos en el proceso y cambio de materias primas, las cuales permiten mejorar el desempeño de la empresa al obtener un beneficio económico, a la vez que se disminuyen los impactos negativos al medioambiente al: Reducir el consumo de materias primas en 2778.53 T y $1 146653.71 Reducir los residuos sólidos en 298.66 T y$ 158887.12 Reducir el costo de energía eléctrica en $$ 71178.

A look to the Electricity Generation from Non-Conventional Renewable Energy Sources in Colombia

This study discusses the potentialities and current situation of the electricity generation from non-conventional renewable energy sources (NCRES) in Colombia. In particular, three scenarios considering the increment of NCRES electricity based generation installed capacity are discussed. The three scenarios are compared to the 2020 forecast of the Energy and Mining Planning Unit ((UPME). Overall, it id shown that Colombia has a significant unused NCRES potential, which makes possible to realize the 6% target for NCRE based electricity generation capacity installed by 2020. In particular, the photovoltaic energy is foresee to account for over half of the NCRE mix. Even though the law 1715 is a progress towards integrating NCRE to the National Electric System, more policies and developments are required, to further the NCRE based installed generation capacities

Energy and exergy assessment of heavy-duty mining trucks. Discussion of saving opportunities

Heavy-duty mining trucks are essential for open-pit mining and are significant energy consumers, stressing the need for the mining industry to improve the fuel economy of mining trucks. However, there is a limited discussion on this topic in the specialized literature, mainly focusing on light-duty vehicles. This article discusses the energy and exergy balances of heavy-duty mining trucks operating in an open pit mine in Colombia. Results show saving opportunities by either using batteries or producing hydrogen with the power from regenerative brakes, reducing heat losses in the engine, recovering heat losses with combustion gases using thermoelectric generators, and replacing mechanical pumps with electrical pumps. The assessment shows that reducing engine heat losses by coating the cylinder, cylinder head, and piston crown can reduce fuel consumption between 1.8 % and 9.1 %. Moreover, the production of hydrogen, while economically feasible, needs to assess the implementation of electrolyzers in mining trucks. Other measures are not economically viable. Using batteries, which requires adding 12 t of weight to the truck, reduces truck productivity. Finally, using thermoelectric generators and replacing mechanical pumps shows marginal opportunities to reduce fuel consumption

Data supporting the assessment of biomass based electricity and reduced GHG emissions in Cuba

Assessing the biomass based electricity potential of developing nations like Cuba can help to reduce the fossil fuels dependency and the greenhouse gas emissions. The data included in this study present the evolution of electricity production and greenhouse gas emissions in Cuba. Additionally, the potentialities to produce biomass based electricity by using the most significant biomass sources in Cuba are estimated. Furthermore, estimations of the potential reductions of greenhouse gas emissions, resulting from implementing the biomass based electricity potential of the different sources discussed in the study, are included. Results point to the most promising biomass sources for electricity generation and their potential to reduce GHG emissions

Experiencias en la utilización de información meteorológica para el pronóstico y control del consumo de electricidad en hoteles

Ponencia presentada en: XI Congreso de la Asociación Española de Climatología celebrado en Cartagena entre el 17 y el 19 de octubre de 2018.[ES]Los hoteles se encuentran entre las instalaciones turísticas de mayor consumo de energía. Para supervisar y controlar el consumo mensual y anual de energía en los hoteles se han propuesto diferentes indicadores. Estos indicadores, desarrollados en base anual, no permiten la rápida detección y mitigación de las malas prácticas y sobreconsumos en las instalaciones del hotel. Este estudio analiza el uso de indicadores de desempeño energético para evaluar y controlar el consumo de electricidad en los hoteles. Para este fin se introduce un nuevo indicador teniendo en cuenta la temperatura exterior. Sobre la base de este indicador se desarrollan las gráficas de control diarios, lo que permite una detección más rápida de sobreconsumos y malas prácticas hacia una mayor eficiencia de la electricidad. Una ventaja de este enfoque es que no se requieren inversiones para ponerlo en práctica. Las herramientas se aplicaron en dos hoteles cubanos de diferentes características, donde se alcanzaron importantes reducciones del consumo de electricidad.[EN]Hotels are among the most energy intensive tourism facilities. To monitor and control the monthly and yearly energy consumption in hotels, different indicators have been proposed. These indicators do not consider the influence of physical parameters such as outdoor temperature, or, when they do, rather complex coefficients are used, precluding implementation in hotel facilities. This study discusses the use of Energy Performance Indicators to assess and control the electricity consumption in hotels. To this end a new indicator considering the outdoor temperature is introduced. Based on this indicator daily control graphs are developed, allowing a more rapid detection of overconsumptions and malpractices towards higher electricity efficiency. The tools were implemented in two Cuban hotels of different characteristics, where significant reductions of the electricity consumption were achieved

Assessment criteria of the feasibility of replacement standard efficiency electric motors with high-efficiency motors

Currently, the feasibility to replace standard efficiency electric motors with higher efficiency ones is assessed with considerations differing from real operating conditions in the industry. This study compares the feasibility of replacing 26 standard efficiency motors (IE1) with high-efficiency efficiency ones (IE2 and IE3) in a sugar plant, based on three different energy scenarios and considering the incremental costs or depreciated costs of motors. Energy scenario 1 consider that motors operate for 6000 h/year at full load and nominal efficiency. While scenarios 2 and 3 consider the measured operating time and the load factor of motors. The results show that scenario 1 overestimates electricity consumption between 2 and 18 times, contrasted with a difference of 1e7% in scenarios 2 and 3, leading to saving potentials in scenario 1 between 1.2 and 33.4 times higher than for scenarios 2 and 3. Considering the incremental costs in scenario 1, it is feasibly to replace all the motors in the plant, while it is only feasibly to replace three motors in scenarios 2 and 3 with the depreciated costs. Therefore, the use of scenario 1 based on unrealistic conditions and leading to economic loss, should be avoided in future studies