Análisis termodinámico de un sistema para generar energía eléctrica a partir de la energía mecánica de un gas natural

The objective of this work is to design a system for generating electricity from the mechanical energy of a natural gas at high pressure. The main motivation for the development of the research is based on the need to detect by the natural gas distribution industry, where it is considered that the use of the mechanical energy of natural gas (flow energy and kinetic energy) can be used for the Electric power generation, through a turbo expander, and thus power the electromechanical components of a substation. In this way, energy consumption costs are reduced, which translates into unquestionable gains in energy efficiency. The methodology applied is based on the use of physical principles such as the conservation of mass and energy in a control volume. Likewise, the guidelines established in the guideline for the expression of measurement uncertainty allowed us to estimate an interval where the real value of the mechanical power generated at the output of the turboexpander is found. Based on experimental data in a natural gas distribution substation, the consolidated results allowed quantifying the average mechanical power at the inlet of a turboexpander (8155 W) and, in the typical situation where the turboexpander reduces its outlet pressure to 50% , an average mechanical power is generated at the output of the turboexpander equal to 4893 W, which translates into an efficiency of 40%. This research work allowed us to conclude that the design of a system for electric power generation is viable based on the thermodynamic and dimensional parameters associated with the natural gas distribution system, as well as the mechanical power that can be generated at the exit of a turboexpander.Este trabajo tiene por objetivo diseñar un sistema de generación de energía eléctrica a partir de la energía mecánica de un gas natural a alta presión. La motivación principal para el desarrollo de la investigación se fundamenta en la necesidad detectar por la industria de distribución de gas natural, donde se considera que el aprovechamiento de la energía mecánica del gas natural (energía de flujo y energía cinética) puede ser aprovechado para la generación de energía eléctrica, a través de un turbo expansor, y así alimentar los componentes electromecánicos de una subestación. De esta forma se disminuyen costos de consumo de energía lo que se traduce en incuestionables ganancias de eficiencia energética. La metodología aplicada se basa en la utilización de principios físicos como lo son la conservación de masa y energía en un volumen de control. De igual forma, lo lineamiento establecidos en la guía para la expresión de la incertidumbre de medición, permitió estimar un intervalo donde se encuentra el valor real de la potencia mecánica generada a la salida del turbo expansor. A partir de datos experimentales en una subestación de distribución de gas natural, los resultados consolidados permitieron cuantificar la potencia mecánica promedio en la entrada de un turbo expansor (8155 W) y, en la situación típica donde el turbo expansor reduce su presión de salida al 50%, se genera una potencia mecánica promedio a la salida del turbo expansor igual a 4893 W, lo que se traduce en una eficiencia de 40%. Este trabajo de investigación permitió concluir que el diseño de un sistema para generación de energía eléctrica es viable a partir de los parámetros termodinámicos y dimensionales asociadas al sistema de distribución de gas natural, así como la potencia mecánica que puede ser generada a la salida de un turbo expansor

Thermodynamic Analysis of aSystem to Generate Electrical Energy from the Mechanical Energy of aNatural Gas

The objective of this work is to design a system for generating electricity from the mechanical energy of anatural gas at high pressure. The main motivation for the development of the research is based on the need to detect by the natural gas distribution industry, where it is considered that the use of the mechanical energy of natural gas (flow energy and kinetic energy) can be used for the Electric power generation, through a turbo expander, and thus power the electromechanical components of a substation. In this way, energy consumption costs are reduced, which translates into unquestionable gains in energy efficiency. The methodology applied is based on the use of physical principles such as the conservation of mass and energy in a control volume. Likewise, the guidelines established in the guideline for the expression of measurement uncertainty allowed us toestimate an interval where the real value of the mechanical power generated at the output of the turboexpanderis found. Based on experimental data in a natural gas distribution substation, the consolidated results allowed quantifying the average mechanical power at the inlet of a turboexpander(8155 W) and, in the typical situation where the turboexpanderreducesits outlet pressure to 50% , an average mechanical power is generated at the output of the turboexpanderequal to 4893 W, which translates into an efficiency of 40%. This research work allowed us to conclude that the design of a system for electric power generation is viable based on the thermodynamic and dimensional parameters associated with the natural gas distribution system, as well as the mechanical power that can be generated at the exit of a turboexpanderEste trabajo tiene por objetivo diseñar un sistema de generación de energía eléctrica a partir de la energía mecánica de un gas natural a alta presión. La motivación principal para el desarrollo de la investigación se fundamenta en la necesidad detectar por la industria de distribución de gas natural, donde se considera que el aprovechamiento de la energía mecánica del gas natural (energía de flujo y energía cinética) puede ser aprovechado para la generación de energía eléctrica, a través de un turbo expansor, y así alimentar los componentes electromecánicos de una subestación. De esta forma se disminuyen costos de consumo de energía lo que se traduce en incuestionables ganancias de eficiencia energética. La metodología aplicada se basa en la utilización de principios físicos como lo son la conservación de masa y energía en un volumen de control. De igual forma, lo lineamiento establecidos en la guía para la expresión de la incertidumbre de medición, permitió estimar un intervalo donde se encuentra el valor real de la potencia mecánica generada a la salida del turbo expansor. A partir de datos experimentales en una subestación de distribución de gas natural, los resultados consolidados permitieron cuantificar la potencia mecánica promedio en la entrada de un turbo expansor (8155 W) y, en la situación típica donde el turbo expansor reduce su presión de salida al 50%, se genera una potencia mecánica promedio a la salida del turbo expansor igual a 4893 W, lo que se traduce en una eficiencia de 40%. Este trabajo de investigación permitió concluir que el diseño de un sistema para generación de energía eléctrica es viable a partir de los parámetros termodinámicos y dimensionales asociadas al sistema de distribución de gas natural, así como la potencia mecánica que puede ser generada a la salida de un turbo expansor

NEOTROPICAL CARNIVORES: a data set on carnivore distribution in the Neotropics

Mammalian carnivores are considered a key group in maintaining ecological health and can indicate potential ecological integrity in landscapes where they occur. Carnivores also hold high conservation value and their habitat requirements can guide management and conservation plans. The order Carnivora has 84 species from 8 families in the Neotropical region: Canidae; Felidae; Mephitidae; Mustelidae; Otariidae; Phocidae; Procyonidae; and Ursidae. Herein, we include published and unpublished data on native terrestrial Neotropical carnivores (Canidae; Felidae; Mephitidae; Mustelidae; Procyonidae; and Ursidae). NEOTROPICAL CARNIVORES is a publicly available data set that includes 99,605 data entries from 35,511 unique georeferenced coordinates. Detection/non-detection and quantitative data were obtained from 1818 to 2018 by researchers, governmental agencies, non-governmental organizations, and private consultants. Data were collected using several methods including camera trapping, museum collections, roadkill, line transect, and opportunistic records. Literature (peer-reviewed and grey literature) from Portuguese, Spanish and English were incorporated in this compilation. Most of the data set consists of detection data entries (n = 79,343; 79.7%) but also includes non-detection data (n = 20,262; 20.3%). Of those, 43.3% also include count data (n = 43,151). The information available in NEOTROPICAL CARNIVORES will contribute to macroecological, ecological, and conservation questions in multiple spatio-temporal perspectives. As carnivores play key roles in trophic interactions, a better understanding of their distribution and habitat requirements are essential to establish conservation management plans and safeguard the future ecological health of Neotropical ecosystems. Our data paper, combined with other large-scale data sets, has great potential to clarify species distribution and related ecological processes within the Neotropics. There are no copyright restrictions and no restriction for using data from this data paper, as long as the data paper is cited as the source of the information used. We also request that users inform us of how they intend to use the data

Global economic burden of unmet surgical need for appendicitis

Background There is a substantial gap in provision of adequate surgical care in many low- and middle-income countries. This study aimed to identify the economic burden of unmet surgical need for the common condition of appendicitis. Methods Data on the incidence of appendicitis from 170 countries and two different approaches were used to estimate numbers of patients who do not receive surgery: as a fixed proportion of the total unmet surgical need per country (approach 1); and based on country income status (approach 2). Indirect costs with current levels of access and local quality, and those if quality were at the standards of high-income countries, were estimated. A human capital approach was applied, focusing on the economic burden resulting from premature death and absenteeism. Results Excess mortality was 4185 per 100 000 cases of appendicitis using approach 1 and 3448 per 100 000 using approach 2. The economic burden of continuing current levels of access and local quality was US $92 492 million using approach 1 and$73 141 million using approach 2. The economic burden of not providing surgical care to the standards of high-income countries was $95 004 million using approach 1 and$75 666 million using approach 2. The largest share of these costs resulted from premature death (97.7 per cent) and lack of access (97.0 per cent) in contrast to lack of quality. Conclusion For a comparatively non-complex emergency condition such as appendicitis, increasing access to care should be prioritized. Although improving quality of care should not be neglected, increasing provision of care at current standards could reduce societal costs substantially