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Este trabajo investiga varios escenarios de gestión de residuos en el departamento de Boyacá, Colombia. Investigaciones anteriores han identificado los riesgos potenciales de una gestión inadecuada de los residuos, incluyendo la disposición de grandes cantidades de materia orgánica que aumentan los niveles de CH4 , NOx , SOx , O3 , CO2 , carbono negro (CN) y carbono orgánico (CO). A pesar de la relativamente vida corta de estos contaminantes, cambios en el sector de los residuos sólidos y las políticas de disposición final generan un impacto significativo en la calidad del aire urbano, los ecosistemas y la salud. De esta forma, este trabajo propone un método de estimación de contaminantes climáticos de vida corta desde el año 2000 hasta el año 2050 basado en la recolección de datos disponibles en el sector de residuos de Boyacá. Los modelos de estimación se han realizado utilizando la herramienta SWEET 2.0, una iniciativa de la Coalición para el Clima y el Aire Limpio del Programa de las Naciones Unidas para el Medio Ambiente. Cada modelo incluye una línea base y el análisis de tres escenarios: (1) nueva instalación de compostaje; (2) mejora del vertedero y (3) ampliación del reciclaje. Los resultados indican que para el año 2050 los niveles de contaminación atmosférica seguirán mostrando una tendencia creciente, por lo que debería realizarse un análisis detallado de la situación actual de la gestión de residuos. En el futuro, se debe

The co-processing of Jatropha curcas L oil (JC) and gasoil in mixtures of 20:80 and 50:50 volume percentages, respectively, was carried out in a batch reactor by using a commercial NiMo/Al2O3 (5wt%) catalyst at 750 rpm, 70 bar of initial pressure and 80/100 mesh particle size. The effect of temperature (370-390 °C) at fixed reaction time of 4 h in the oxygen and sulfur removals were followed with Fourier Transform Infrared Spectroscopy, Proton Nuclear Magnetic Resonance and Energy Dispersive X-ray Fluorescence Spectroscopy. Also we use simulated distillation to determine the boiling point distributions. It was found that 98 and 99 % conversions of vegetable oils were obtained for 20 and 50 vol% JC feedstocks and similar ∼ 83 and 87 % hydrodesulfuration (HDS) conversions for both fossil-vegetable mixtures at 380 and 390 °C. However at 370 °C the attained HDS conversion was more than 10% lower in mixture with 50 vol% JC. Regarding boiling point distributions, yields averaging 58 vol% and 70 vol% of cut with boiling range 157-343 °C, were obtained with 20 vol% and 50 vol% JC feed mixtures, respectively.

To obtain some insights into the transport of macroemulsions prepared outside of the reservoir for oil recovery through porous media, laboratory experiments were run by injecting different formulations of diluted oil in water emulsions through sandstone cores. Emulsions, whose disperse phase was 70%, were stable for one year. Mathematical model parameters were fitted with data from emulsion transport experiments. According to this model, it is enough to inject 0.1 pore volume of emulsion slug for its adequate transportation through porous media. Oil displacement tests were carried out as part of a secondary recovery process, followed by the injection of an emulsion slug, and then again by water flooding to obtain additional oil recovery up to 23.5%. At the same concentration, emulsions based on a hydrophobic compound were more effective than emulsions prepared from crude oil, obtaining a difference of cumulative residual oil recovery of around 12%. The injection of an emulsion slug at 1 wt.% of concentration and 0.1 pore volume after waterflooding is both a promising alternative and technically viable additional recovery method. Emulsions were stable for a long time and easyly diluted with water, which can be very useful in mature oilfields.

A dynamic, plug-flow, one-dimensional, and heterogeneous mathematical model for a trickle-bed reactor is described and used to simulate the catalytic hydrocracking of non-edible vegetable oil with countercurrent operation mode. The reactor model considers the hydrocracking reaction of triglycerides towards renewable fuels, which is present in the hydrotreatment process of vegetable oils. The dynamic model was first validated using experimental data reported in the literature, which were obtained in an isothermal micro-scale reactor with cocurrent downflow during hydrocracking of Jatropha oil over a commercial CoMo catalyst. Then, the three-phase reactor model was applied to predict the dynamic behavior of an industrial hydrocracking reactor in order to gain some insight into the transient behavior of the liquid molar concentration, partial pressure, and temperature profiles, which were obtained and discussed as a function of time and axial position of the catalytic bed. The simulations obtained with the proposed dynamic model showed good agreement with the experimental data and trends previously reported for the operation variables profiles at steady-state and relevant findings at industrial scale were obtained. One of the main challenges to produce biofuels by vegetable oils hydroprocessing is to control the high-temperature gradients along the catalyst bed because of the high reaction heat released; therefore, the development of dynamic trickle-bed reactor models, as shown in this work, can be used as a tool to predict the operational behavior of the unit under different reaction conditions and layouts to found the best scheme to control the effects by high-temperature rise.

The silicon composition effect on acidic properties of Ni[sbond]Mo catalysts was investigated for hydrocracking reaction, where an optimal Si and Al ratio is required for the formation of B...

Renewable biodiesel with a high content of n-C17 alkanes was prepared through the catalytic hydrodeoxygenation of oleic acid under optimum conditions of temperature, reaction time and weight percentage of Ni deposited in γ-Al2O3. The hydrotreated vegetable oil (HVO) was blended with petrodiesel (20 % and 40 % of HVO) to evaluate its behaviour in a diesel engine. Comparative studies of power and emission of atmospheric pollutants such as NOx, CO, HC and smoke were evaluated under prepared blends and petrodiesel. The presence of HVO biodiesel at full load generated a slight decrease in power compared to petrodiesel; however, the decrease in emission of pollutants when using the blends containing HVO was significant. In the case of 40 % HVO were able to reduce more of 20 % of CO and HC emissions, and more than 40 % reduction in smoke when compared with petrodiesel. The NOx emissions of the blends with HVO had a significant slightly decrease. Further, the properties of Ni/γ-Al2O3 catalysts are justified by the results of EDS characterization, surface area (SBET), XRD, XPS, HR-TEM and it’s capacity to produce biodiesel.

Asphaltenes were precipitated from atmospheric residue and divided into two fractions. One of them was left as such and the second one was submitted to washing under reflux. Characterization of both fractions was carried out through elemental analysis and X-ray diffraction. Diffractograms were analyzed in order to obtain crystallite parameters by smoothing processes previous to deconvolution and then local maxima of a polynomial function were detected. Major peaks were found at around 20°, 25°, and 41° corresponding to γ, (002) and (10) bands. Bragg and Scherrer equations were used to determine the aromatic interlayer and aliphatic distances, as well as thickness and diameter of aromatic sheets. The full-width at half-maximum (FWHM) of the main peaks was firstly estimated using the corrector formula, and therefore the corrector procedure was applied to improve the initial guesses of FWHM. Differences in crystallite parameters between both analyzed samples were observed when using this mathematical...

The aim of this work is to estimate some nitrogen (N)-adsorption properties and the N-adsorption capacity (q) required for commercial application in the ultra-low sulfur diesel production. Hydroxyl (OH) groups and interactions among the commercial adsorbent Selexsorb® CDX (CDX) and pyridine and indole were studied by means of Fourier transform infrared spectroscopy. The adsorption of N-compounds from three diesel fuels over CDX was estimated at CDX/fuel ratio: 0.01–0.09 g/g, Contact time: 1–60 m, 303 K, and 0.078 MPa in a batch setup. It was concluded that an appropriate N-adsorbent should have high densities of suface OH groups and Lewis and Bronsted strong-acid sites and a q ≥ 0.70 mmol/g.

In recent years, many studies have been published on the hydrotreating of non-edible vegetable oils, however, a limited number of them deal with the hydroprocessing of their corresponding fatty acid methyl esters for the productions of renewable fuels. In this study is outlined the production of renewable fuels from castor bean seeds (Ricinus communis L.) in two stages, the first one is to obtain the respective castor oil methyl esters by reactive extraction and the second one is to apply the hydrotreating process to these methyl esters by using a commercial NiMo/γ-Al2O3 catalyst in an isothermal batch reactor. A method was used to characterize the feedstock and the hydrotreating products from their TGA data by applying a proposed correlation equation for converting thermogravimetric measurements into simulated distillation results. Then, these estimated simulated distillation curves were used to obtain finally their characterization by composition based on real components. A chemical reaction network of four lumps along with its lumped kinetic model representing the hydrotreating of castor oil methyl esters was obtained from experiments conducted in a batch reactor operating under isothermal conditions at 395, 410, and 425 °C, 50 barg, and with reaction times from 2 to 4 h, and it was found that at severe operating conditions the yield and product selectivity of kerosene fraction increases, therefore, in order to obtain a higher production of renewable diesel fraction in this reaction system, the hydrotreating reaction time and temperature must be moderate.

The aim of this work was to study the removal of nitrogen (N-) compounds for ultra-low sulfur diesel (ULSD) production purposes by using three commercial materials: selexsorb® CDX (CDX), silica gel (SG), and activated carbon VG-077 (VG-077). The experiments were conducted in three steps: (1) Adsorption of quinoline, indole, or carbazole from model fuels (300wppm in a 1:1g/g nhexadecane:toluene mixture) in a batch setup; adsorption of N- compounds from straight run gas oil (SRGO): (2) in a batch setup, and (3) in a fixed-bed column (FBC). Langmuir and Freundlich models were considered for modeling the adsorption isotherms of quinoline, indole, carbazole from model fuels and N-compounds from SRGO. Clark and Thomas models were employed for fitting the FBC

A review of the state of art in the denitrogenation process of middle distillates using adsorbent materials is discussed. More stringent environmental laws enforce refiners to produce cleaner fuels from heavy feeds. Sulfur compounds reduce fuel quality and release pollutants to the atmosphere by which its elimination is mandatory. Typical hydrodesulfurization (HDS) catalytic processes in refineries are limited to meet the required specifications for Ultra Low Sulfur Diesel (ULSD) and new processes and materials need to be developed. Removal of nitrogen compounds (N-compounds) from real feedstocks improves sulfur elimination because irreversible adsorption of N-compounds on acidic sites in HDS catalysts may be avoided. Research and development during the last decade is reviewed in this work, including results obtained with different types of N-compounds, adsorptive systems and adsorbents commercially available.

Due to the depletion of crude reserves and the increasing demand for clean hydrocarbon fuels the production of renewable materials-based fuels has emerged to solve at least partially this problem in the past decade and it is expected to continue [1,2]. Green fuels can be classified as naphtha, jet fuel, and diesel. In the case of green diesel, its increasing demand could reach 900 million tons by 2020 [3].