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Biodiesel Production from Waste Cooking Oil by Enzymatic Catalysis Process

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Journal of Chemistry and Chemical Engineering 2013年第10期7卷 993-1000页

作者： ignacio contreras andrade Fabio Emiro Sierra Vargas Carlos Alberto Guerrero Fajardo Department of Biology and Chemistry University of Sinaloa Culiacan 80007 Mexico Department of Chemistry National University of Colombia Bogota 11001 Colombia

Biodiesel is an excellent option for reducing dependence on fossil fuels with environmental advantages by reducing hazardous emissions. The enzymatic transesterification has attracted the attention of researchers in the last decade and the advantages of enzymatic catalysis show that the production of biodiesel by this route has good potential, mainly because it is friendly environment. For biodiesel, production process by enzyme catalysis is chosen the response surface methodology. It is an experimental strategy to find the best operating conditions oftransesterification reaction to improve the biodiesel quality. The Process has three variables： temperature, molar ratio oil-alcohol and catalyst quantity. The process was monitored by GC-FID （gas chromatography with flame ionization detector）. The yield of the transesterification reaction by enzymatic catalysis decreases with increasing temperature, and may be due to inactivation of the enzyme by denaturation at temperatures above 50 ℃. The second-order design used was the ＂CDC （central design composition）＂ which produced a maximum yield of 95.5% in the transesterification reaction by enzymatic catalysis obtained at a temperature of 45 ℃, molar ratio methanol：oil of 8：1 and a catalyst loading of 8% wt.

关键词： Biodiesel waste cooking oil transesterification reaction enzymatic catalysis biofuel

Computational Simulation to Predict the Syngas Composition Produced during Charcoal Gasification

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Journal of Chemistry and Chemical Engineering 2014年第9期8卷 889-897页

作者： ignacio contreras-andrade Santiago Ramirez-Rubio Jonathan Parra-Santiago Fabio Sierra-Vargas Carlos Alberto Guerrero-Fajardo Doctor Chemical Engineering Autonomous University of Sinaloa Culiacan Rosales 80040 Mexico Department of Aeronautical Engineering San Buenaventura University Bogota 11001 Colombia Chemical Engineering (C) National University of Colombia Bogota 11001 Colombia Oepartment of Mechanical Engineering National University of Colombia Bogota 11001 Colombia Chemical Engineering and Mechanical Master in Environmental Engineering PhD in Chemical Engineering National Universityof Colombia Bogota 11001 Colombia

Charcoal gasification could mitigate the energetic problems in the rural zones since these regions have considerable amounts of wood, which is the base of such a fuel available. This paper presents some CFD （computational fluid dynamic） predictions of the experimental results obtained from the fixed bed gasification of charcoal made in a pilot-scale downdraft reactor using air, which was designed and built by the Research Group in Clean Development Mechanisms and Energy Management, from the National University of Colombia. The quality of the syngas obtained from the process was evaluated through the CO and CO2 percentages measured in its composition. The performance at various air flow rates （measured at the system entrance, through an analog flow meter） is evaluated with the help of 11 thermocouples, which give the information to create a temperature profile, and three load cells to measure the solid fuel conversion rate. To simulate the process, the information from temperature profile, charcoal proximate analysis, air flow meter and load cells were taken as inputs and the syngas composition was obtained as the result from the calculation. The domain was defined as 2D with an axis-symmetric description, using quads as mesh elements. The calculation and results were performed in a CFD commercial code widely used for this type of simulations： ANSYS FLUENT. The predictions made by the software were validated with the experimental results obtained in the laboratory.

关键词： Biomass charcoal fixed bed gasification syngas CFD.

Biodiesel Production by Enzymatic Catalysis Process Using Two Analytical Ways： Gas Chromatography and Total Glycerol Determination

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Journal of Chemistry and Chemical Engineering 2014年第7期8卷 717-726页

作者： ignacio contreras andrade Jonathan Parra Santiago Jose Ricardo Sodre Joseph Sebastian Pathiyamattom Carlos Alberto Guerrero-Fajardo Doctor Chemical Engineering Universidad Autonoma de Sinaloa Culiacan 80040 Mexico Chemical Engineering (C) Universidad Nacional de Colombia Bogota11001 Colombia Coordinator of the Postgraduate Program in Mechanical Engineering Pontifical Catholic University of Minas Gerais BeloHorizonte 30130 Brazil Center forEnergy Research Universidad Nacional Autonoma de Mexico Temixco 62580 Mexico Chemical Engineering and Mechanical Universidad Nacional de Colombia Bogota 11001 Colombia

Currently, biodiesel is presented as one of the best alternatives for gradually replacing the use of fossil fuels, but it has some factors that make it economically impractical if it does not have a government support. For this reason, research efforts focused on this area have been responsible for optimizing the process of biodiesel production by different catalytic routes to achieve greater efficiency at a lower cost. In this case, the biggest problem has been the high cost generated by an investigation, which in many occasions is the main factor to decide if an investigation could be carried out. Trying to reduce these costs, in the current study, we are using a technique of glycerol quantification by volumetric methods and comparing obtained results with the chromatographic method, which is conventionally used and comparatively much more expensive. Biodiesel employee was obtained by an enzymatic catalysis process varying one of three process variables：oil：alcohol molar ratio, temperature and proportion of catalyst. The numerical differences obtained between the two quantification methods generated relative errors lower than 10%, resulting in some occasions lower than 1%. By gas chromatography analysis the best yield was obtained at the same conditions of the volumetric method, a temperature of 45 ℃, an oil：alcohol ratio 1：4 and 8 wt.% of catalyst, but a yield of 95.5% and 97.1%, respectively. Due to the high precision of gas chromatography, this method is used to carry out a surface response analysis obtaining as ideal operating conditions a temperature of 43.5 ℃, 8.9 wt.%. of catalyst and an oil：alcohol ratio 1：4.

关键词： Biodiesel production glycerol determination gas chromatography enzymatic catalysis.

Modeling of Liquid-Liquid Extraction Process for Glycerol Purification from Biodiesel Production

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Journal of Chemistry and Chemical Engineering 2014年第10期8卷 971-977页

作者： ignacio contreras-andrade Maicol Martinez-Gonzalez Luis Figueroa-Casallas Jonathan Parra-Santiago Carlos Alberto Guerrero-Fajardo Universidad Autonoma de Sinaloa Culiacan Rosales 80040 Mexico Universidad Nacional de Colombia Bogota 11001 Colombia

This paper shows some generalities about the glycerin byproduct obtained from biodiesel production process, presents an analysis of the ternary equilibrium between methanol, water and glycerol, and shows the influence that temperature has on the balance. This phase diagram illustrates ternary equilibrium at 10, 20 and 50 ℃, keeping the pressure constant at 1 atm （atmosphere） to standardize the analysis. The purpose of it is to establish the best temperature for the purification of glycerol by liquid-liquid extraction method under the ＂extraction in several stages cross flow＂ taking an initial mixture of glycerol with composition 15 wt.% water, 25 wt.% methanol and 60 wt.% glycerol. Water was used as liquid-liquid extraction solvent in order to remove as much methanol as possible from the initial solution due to the existence of a zone of insolubility between the glycerol and water in the ternary equilibrium. By this reason, two solutions are obtained, one consisting of water and methanol containing a trace of glycerin and the other consisting of water, glycerine and traces of methanol, which contain only 4.62% of the total methanol which enter in the process of liquid-liquid extraction, with 60.62% of the total glycerol, which is sent to a fractional distillation process to purify glycerin up to 98% by weight.

关键词： Ternary equilibrium liquid-liquid extraction glycerin purification.

Natural Composite Material from Steelwool or Luffa cylindrica under Natural, Rigid and Flexible Resin

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Journal of Chemistry and Chemical Engineering 2014年第9期8卷 906-917页

作者： ignacio contreras-andrade Daniela Rincon-Pardo Carlos Alberto Guerrero-Fajardo Jonathan Parra-Santiago Eliana Guerrero-Romero Doctor Chemical Engineering Autonomous University of Sinaloa Culiacan Rosales 80040 Mexico Industrial Designer Master (C) in Materials and Process Engineering National University of Colombia Bogota 11001 Colombia Chemical Engineering and Mechanical Master in Environmental Engineering PhD in Chemical Engineering National Universityof Colombia Bogota 11001 Colombia Chemical Engineering (C) National University of Colombia Bogota 11001 Colombia Industrial Designer Master of lnformation Technology Central Queensland University Rockhampton QLD 4702 Australia

In a changing world with a high interest in new ecomaterials, natural fibers such as the steelwool or Luffa cylindriea appear in new presentations and mixing with other materials to develop better opportunities to replace synthetic fibers. This work presents a research on the use of steelwool fiber for composite materials, on the basis of the physical properties, that generate conditions of mixing with three binders （matrix） natural： the rosin, artificial hard： polyurethane resin and artificial flexible： flexible twin resin （epoxy） and finally a polyester resin to make a comparison with other major resins. A testing of compression and tension is carried out to the materials analyzed, obtaining three types of composite materials by the above mentioned binders and three proposed presentations of fiber （complete, tissue and ground）. The test tube in tension with polyester resin presented a high rigidity and a percentage of deformation of 14%, resulting in less distortion than the woven with resin polyurethane with 12% of deformation. The presentation with resin polyurethane presented greater resistance to compression, because the resin acts as a sponge absorbing the energy of charge and the join of particles is larger than the other presentations generating greater cohesion among them and avoiding its rupture easily for a load of 2,000 kg. The presentation that is least resisted was the woven in two resins in the stage of energy absorption of load where polyurethane is 800 kg and the flexible twin is 850 kg, because the form of woven fiber distribution creates spaces where there are more resin than fiber.

关键词： Natural fibers steelwool industrial design binder matrix composite materials reinforced polymer.

Transesterification Reaction of Waste Cooking Oil and Chicken Fat by Homogeneous Catalysis

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Journal of Chemistry and Chemical Engineering 2014年第7期8卷 736-743页

作者： ignacio contreras andrade Jonathan Parra Santiago Jose Ricardo Sodre Joseph Sebastian Pathiyamattom Carlos Alberto Guerrero-Fajardo Doctor Chemical Engineering Universidad Autonoma de Sinaloa Culiacan Rosales 80040 Mexico Chemical Engineering (C) Universidad Nacional de Colombia Bogota 11001 Colombia Doctor Mechanical Engineering Coordenador Programa de Pos-Graduaao em Engenharia Mecdnica Pontificia Universidade Catolica de Minas Gerais Belo Horizonte 30130 Brazil Center for Energy Research Universidad Nacional Autonoma de Mexico Temixco 62580 Mexico Chemical Engineering and Mechanical Universidad Nacional de Colombia Bogota 11001 Colombia

In the last years, biodiesel production has been on a steady increase due to it is renewable and biodegradable fuel. The process to obtain biodiesel can be carried out using different raw materials. It is conlmonly performed by transesterification reaction of vegetable oils with methanol and using a homogeneous or heterogeneous catalyst. This work seeks to compare the results produced in transesterification of wasted cooking oil and chicken fat by homogeneous catalysis with NaOH. Due to in each case triglyceride comes from different raw materials, operation conditions differ slightly, which is more evident in the values used for the temperature. For chicken fat was used temperature variations between 35 ℃ and 55 ℃, varying catalyst in percentages between 0.3% and 0.7% with a molar ratio 6：1 in all cases and a reaction time of I h. Likewise, the conditions used in the tmnsesterification process of waste cooking oil were temperature between 50 ℃ and 60 ℃ with a molar ratio 6/1 and 9/1 for alcohol and oil, and catalyst percentage between 0.5% and 0.7% by weight. The yields obtained were between 78% and 94%, or 83% and 95%, for chicken fat and wasted cooking oil, respectively.

关键词： Biodiesel transesterification homogeneous catalysis cooking oil chicken fat.

Endotoxin-induced alterations of adipose tissue function:a pathway to bovine metabolic stress

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Journal of Animal Science and Biotechnology 2024年第4期15卷 1391-1407页

作者： Miguel Chirivi G.Andres contreras Department of Large Animal Clinical Sciences Michigan State UniversityEast LansingMIUSA

During the periparturient period, dairy cows exhibit negative energy balance due to limited appetite and increased energy requirements for lactogenesis. The delicate equilibrium between energy availability and expenditure puts cows in a state of metabolic stress characterized by excessive lipolysis in white adipose tissues(AT), increased production of reactive oxygen species, and immune cell dysfunction. Metabolic stress, especially in AT, increases the risk for metabolic and inflammatory diseases. Around parturition, cows are also susceptible to endotoxemia. Bacterial-derived toxins cause endotoxemia by promoting inflammatory processes and immune cell infiltration in different organs and systems while impacting metabolic function by altering lipolysis, mitochondrial activity, and insulin sensitivity. In dairy cows, endotoxins enter the bloodstream after overcoming the defense mechanisms of the epithelial barriers, particularly during common periparturient conditions such as mastitis, metritis, and pneumonia, or after abrupt changes in the gut microbiome. In the bovine AT, endotoxins induce a pro-inflammatory response and stimulate lipolysis in AT, leading to the release of free fatty acids into the bloodstream. When excessive and protracted, endotoxin-induced lipolysis can impair adipocyte's insulin signaling pathways and lipid synthesis. Endotoxin exposure can also induce oxidative stress in AT through the production of reactive oxygen species by inflammatory cells and other cellular components. This review provides insights into endotoxins' impact on AT function, highlighting the gaps in our knowledge of the mechanisms underlying AT dysfunction, its connection with periparturient cows' disease risk, and the need to develop effective interventions to prevent and treat endotoxemia-related inflammatory conditions in dairy cattle.

关键词： Adipose tissue dysfunction Endotoxin Inflammation Insulin resistance

Inversion of walkaway VSP data in the presence of lateral velocity heterogeneity

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Energy Geoscience 2024年第2期5卷 304-313页

作者： Vladimir Grechka Ilya Tsvankin Pedro contreras CWP Department of GeophysicsColorado School of MinesGoldenCO80401USA PDVSA-INTEVEP Apartado 76343Caracas1070AVenezuela Borehole Seismic LLC USA Department of Physics ULAVenezuela

Multi-azimuth walkaway vertical seismic profiling is an established technique for the estimation of in situ slowness surfaces and inferring anisotropy ***,this technique requires the assumption of lateral homogeneity,which makes the horizontal slowness components at depths of downhole receivers equal to those measured at the *** violations of this assumption,such as lateral heterogeneity or nonzero dip of intermediate interfaces,lead to distortions in reconstructed slowness surfaces and,consequently,to errors in estimated anisotropic *** this work,we relax the assumption of lateral homogeneity and discuss how to correct vertical seismic profile data for weak lateral *** describe a procedure of downward continuation of recorded traveltimes that accounts for the presence of both vertical inhomogeneity and weak lateral heterogeneity,which produces correct slowness surfaces at depths of downhole receivers,noticing that sufficiently dense receiver coverage along a borehole is required to separate influences of vertical and lateral heterogeneity on measured traveltimes and obtain accurate estimates of the slowness *** the slowness surfaces are found and a desired type of anisotropic model to be inverted is selected,the corresponding anisotropic parameters,providing the best fit to the estimated slownesses,can be *** invert the slowness surfaces of P-waves for parameters of the simplest anisotropic model describing dipping fractures(transversely isotropic medium with a tilted symmetry axis).Five parameters of this model,namely,the P-wave velocity V0 in the direction of the symmetry axis,Thomsen's anisotropic coefficients e and d,the tilt n,and the azimuth b of the symmetry axis,can be estimated in a stable manner when maximum source offset is greater than half of receiver depth.

关键词： Walkaway vertical seismic profile Lateral velocity heterogeneity Anisotropic parameter estimation Vertical inhomogeneity

Corrosion testing of X52 and X80 steels immersed in stimulated emulsions using a real petroleum sample

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Petroleum Research 2024年第2期9卷 304-316页

作者： L.M.Quej-Ake J.L.Alamilla A.contreras Instituto Mexicano del Petróleo Eje Central Lázaro CárdenasNorte 152San Bartolo AtepehuacanGustavo A.MaderoCiudad de MéxicoC.P.07730México

The aim of this study is to evaluate the internal corrosion process on X52 and X80 steels/real petroleum interfaces containing condensed hydrocarbon plus oilfield-produced water,which were subjected to stimulated emulsions using 50/50 vol ratio mixtures at 45℃,different hydrodynamic conditions,1 h,and 24 h.A washing process by using deionized water was proposed to simulate and identify the corrosiveness of the hydrocarbon phase after 24 h of exposure *** characterization by electrochemical impedance spectroscopy and the monitoring of the polarization curves indicated that X80 steel/oilfield-produced water interfaces were more susceptible to corrosion than X52 steel exposed to oilfield-produced *** combined speed rotation of 600 rpm using a magnetic stirrer+600 rpm using a rotating disk electrode decreased the corrosion rate on X52 *** stimulated emulsions made of hydrocarbon+oilfield-produced water and hydrocarbon+deionized water at 24 h increased the corrosion rate on X80 steel(0.34 mm/year and 0.43 mm/year,respectively),promoting the formation of erosion and pitting *** types of corrosion depended mainly on the physicochemical properties of the hydrocarbon,oilfield-produced water,exposure times,and hydrodynamic systems in which the hydrocarbon was studied.

关键词： Corrosion Emulsions X52 steel X80 steel