Papers by Victor Marulanda
La mezcla de combustible diésel con biodiesel se ha venido usando el en país hace varios años. Su... more La mezcla de combustible diésel con biodiesel se ha venido usando el en país hace varios años. Su implementación tiene que ver con la mayor eficiencia de combustión, reducción de material particulado, monóxido de carbono e hidrocarburos, con un leve aumento de emisiones de NOx. Diversas investigaciones han mostrado las ventajas de usar mezclas diésel-biodiesel-etanol y diésel-biodiesel-etanol-agua para la mejora de propiedades del combustible tales como lubricidad y punto de niebla, así como una mayor sustentabilidad por la reducción adicional de emisiones, incluso las de NOx. Las investigaciones se han centrado en hallar una proporción adecuada de tal forma que la mezcla sea estable. En estas mezclas, el biodiesel actúa como emulsionante del etanol y agua y la reducción en emisiones de NOx se atribuye a la temperatura de reacción más baja por la presencia de agua. A pesar de que el biodiesel puede producirse a partir de etanol, haciéndolo 100% renovable, limitaciones técnicas relac...
CT&F - Ciencia, Tecnología y Futuro, 2017
A subcritical hydrolysis of Kikuyu grass lignocellulose residues was carried out in batch and sem... more A subcritical hydrolysis of Kikuyu grass lignocellulose residues was carried out in batch and semi batch mode operations. Experiments assessed the effect of temperature (250-300 °C), mass ratio (6:1-30:1), pressure (1 490-3 190 psi), and water flow rate (3-9 ml/min) in reducing sugars (RS) yield. Reducing sugar production was measured by means of the DNS method, and efficiency was calculated as the ratio between the mass of produced reducing sugars and the total mass of the residue fed to the reactor. A maximum RS of 9.7% was measured in batch hydrolysis experiments at 300 °C, 30:1 mass ratio and 3 190 psi, whereas 22% accumulated RS yield was obtained in semi batch experiments at 300 °C, 2 000 psi and 9 ml/min. The lower yield was attributed to the extended reaction time in batch experiments in comparison to semi batch experiments, in which the reaction time is not only shorter but also the hydrolysis products are continuously removed from the reactor. Analysis of Variance of data for batch experiments showed only the interaction between temperature and mass ratio to be significant, whereas the pressure had no significant effect. A notorious decrease in pH was measured with increasing reaction times due to the formation of acidic degradation products. The results showed the feasibility of producing reducing sugars from lignocellulosic residues available in large amounts and currently discarded without any utilization through subcritical hydrolysis.
CT&F - Ciencia, Tecnología y Futuro, 2015
S upercritical transesterification experiments of beef tallow with ethanol were carried out in a ... more S upercritical transesterification experiments of beef tallow with ethanol were carried out in a batch reactor in order to assess the effect of temperature (350-400°C), reactant molar ratio (9:1-15:1) and reaction time (8-40 min). Composition of the produced biofuel was assessed in terms of the percentage of peak area of the long chain Fatty Acid Ethyl Esters (FAEEs) identified, including also the decomposition products generated as a result of thermal cracking or cis-trans isomerization reactions. Thermal decomposition of FAEEs produced from beef tallow included short chain ethyl esters (C8-C13), ethyl pentadecanoate (C15:0), heptadecanoate (C17:0), not initially present or prevalent in triglycerides sources, as well as ethyl stearate (C18:0) and n-alkanes. Glycerol decomposition reactions were also verified by the presence of glycerol ethers and water content in the produced biodiesel. The highest conversion of triglycerides was verified at 400°C, 15:1 triglycerides to ethanol molar ratio and 40-minute reaction time. At these conditions, ethyl oleate (C18:1) decomposed completely to form cis-trans isomers as well as ethyl octadecanoate (C18:0), which was attributed to double bond hydrogenation reactions. Short chain ethyl esters and glycerol decomposition products have the potential to benefit certain properties of the fuel such as viscosity and cold flow.
Brazilian Journal of Chemical Engineering, 2011
The scale-up of a supercritical water oxidation process, based on recent advancements in kinetic ... more The scale-up of a supercritical water oxidation process, based on recent advancements in kinetic aspects, reactor configuration and optimal operational conditions, depends on the research and development of simulation tools, which allow the designer not only to understand the complex multiphysics phenomena that describe the system, but also to optimize the operational parameters to attain the best profit for the process and guarantee its safe operation. Accordingly, this paper reports a multiphysics simulation with the CFD software Comsol Multiphysics 3.3 of a pilot plant reactor for the supercritical water oxidation of a heavily PCBcontaminated mineral transformer oil. The proposed model was based on available information for the kinetic aspects of the complex mixture and the optimal operational conditions obtained in a lab-scale continuous supercritical water oxidation unit. The pilot plant simulation results indicate that it is not feasible to scale-up directly the optimal operational conditions obtained in the isothermal lab-scale experiments, due to the excess heat released by the exothermic oxidation reactions that result in outlet temperatures higher than 600°C, even at reactor inlet temperatures as low as 400°C. Consequently, different alternatives such as decreasing organic flowrates or a new reactor setup with multiple oxidant injections should be considered to guarantee a safe operation.
Revista Colombiana De Gastroenterologia, Dec 1, 2008
Biodiesel production by means of supercritical transesterification has proved to be an efficient ... more Biodiesel production by means of supercritical transesterification has proved to be an efficient method to overcome the triglycerides feedstock and catalyst related drawbacks of the conventional acid and base catalyzed biodiesel production processes. However, the supercritical process still struggles with the expectedly high environmental and production costs burdens derived of the use of high alcohol to oil molar ratios, usually around 42:1. More recently, several authors have conducted studies of supercritical transesterification using lower molar ratios (6:1 to 18:1) and higher reaction temperatures (350 to 400 °C), in order to decrease the alcohol recovery energy consumption. In this work, a supercritical transesterification process carried out at 400°C and a 9:1 reactants molar ratio is simulated in Aspen plus 2006, based on available experimental information on process conditions and reaction products. As a result of the decreased molar ratio, the calculated energy consumption...
Chemical engineering transactions, 2019
Second generation biofuels are those produced from lignocellulosic biomass or crops that do not c... more Second generation biofuels are those produced from lignocellulosic biomass or crops that do not compete with food production. Cellulose and hemicellulose in plants can be transformed to building blocks, pentoses and hexoses, by hydrolysis. However, most processes require a physic-chemical pretreatment to remove lignin, which acts as a barrier for chemicals during hydrolysis. In fact, pretreatment for removal of lignin or lignin byproducts formed during hydrolysis can be considered as limiting steps for subsequent sugar transformation processes. Alternatively, industrial cellulosic residues, in which lignin and most of hemicellulose have been previously removed through chemical treatment, could be used as raw material for the production of reducing sugars without the drawbacks related to pretreatment and purification steps. Such is the case for diaper industry, which generates a polyacrylate-cellulose dust (POCEL), which cannot be recycled to the process. POCEL is comprised by around...
In this work, the supercritical transesterification of fat with methanol was studied at temperatu... more In this work, the supercritical transesterification of fat with methanol was studied at temperatures 350 to 400 °C, pressures to 300 bars and methanol to fat molar ratios 3:1 to 12:1 in a continuous unit. The identified products in the biodiesel phase included not only the long chain methylesters but also small chain methylesters originated in the decomposition reactions of long chain methylesters, as well as linear alkanes and alkenes. In the aqueous phase several glycerol decomposition products were identified. Glycerol methanolysis and dehydration reactions originated several byproducts such as glycerol ethers and polyglycerols. Some of these products have been used as fuel or fuel additives and therefore could increase the yield of the biodiesel and improve certain properties of the fuel.
Ciencia Tecnologia y Futuro, 2015
espanolLos experimentos de transesterificacion supercritica de sebo vacuno con etanol se llevaron... more espanolLos experimentos de transesterificacion supercritica de sebo vacuno con etanol se llevaron a cabo en un reactor batch con el fin de evaluar el efecto de la temperatura (350 - 400°C), relacion molar de reactantes (9:1-15:1) y tiempo de reaccion (8 - 40 min). La composicion del biocombustible producido se evaluo en terminos del porcentaje de area de picos de los esteres etilicos de acidos grasos o FAEEs (Fatty Acid Ethyl Esters) asi como los productos de descomposicion generados de reacciones de cracking o isomerizacion. La descomposicion termica de los FAEEs producidos incluyo esteres etilicos de cadena corta (C8 - C13), etil pentadecanoato (C15:0), heptadecanoato (C17:0), los cuales no proceden de acidos grasos presentes en el sebo, asi como etil estearato (C18:0) y n-alcanos. De la misma forma, se verifico la ocurrencia de reacciones de descomposicion de la glicerina por medio de la identificacion de eteres y del contenido de agua en el biodiesel. La maxima conversion de tri...
Process for the destruction of toxic residues via oxidation in (21) Appl. No.: 13/133,195 the pre... more Process for the destruction of toxic residues via oxidation in (21) Appl. No.: 13/133,195 the presence of water and oxygen developed in homogenous phase at temperatures over 374° C. and pressure of at least (22) PCT Filed: Dec. 17, 2009 220 atmospheres and a continuous mobile unit easily trans ferred to treat effluents or contaminated media. This mobile (86). PCT No.: PCT/B09/55831 unit is composed of a reactor, which includes pressurization, reaction, cooling, depressurization and sampling Zones for S371 (c)(1), the destruction of toxic residues like polychloride biphenyls (2), (4) Date: Jun. 7, 2011 (PCBs), pyridines, and other hazardous compounds.
ABStra Ct PCBs are one of the best known of the twelve compound classes defined as persistent org... more ABStra Ct PCBs are one of the best known of the twelve compound classes defined as persistent organic pollutants (POP) by the Stockholm Convention and, therefore, actions are required to reduce the utilization of, and to eliminate, in an environmentally sound manner, all wastes contaminated with PCBs as soon as possible, but before 2028. An initial inventory of PCBs in Colombia, according to the guidelines of the Stockholm Convention, accounts for the existence of approximately 13,000 tons of PCBs wastes. However, there are no available state-of-theart incineration facilities that can deal with PCBs in the region, and thus local PCBs wastes must be exported. Accordingly, this paper presents a critical, not necessarily exhaustive, review of catalytic and supercritical technologies for the destruction of PCB wastes. Data concerning the destruction of PCBs reported during the period 2000-2010 are evaluated in this review. The possibility of application of such technologies is assessed ...
Journal of Cleaner Production, 2012
A simulation of a biodiesel production process by supercritical transesterification was carried o... more A simulation of a biodiesel production process by supercritical transesterification was carried out in Aspen PlusÒ 2006, based on lab scale experimental results obtained at a continuous reactor working at a 9:1 methanol to triglycerides molar ratio and 400 C. Simulation results showed that for a specified biodiesel production plant capacity set at 10,000 tons/year the total energy consumption of this process (573 kW) was considerably lower than that of a previously reported supercritical process working at a 42:1 molar ratio and 300 C (2407 kW), and the conventional base catalyzed process (2326 kW). Mass flow rates, stream compositions and energy consumption of each process were used to assess the potential environmental impact (PEI) output of each alternative, in order to select the most environmentally friendly one, through a process design tool developed by the Environmental Protection Agency (EPA), the generalized Waste Reduction (WAR) algorithm. The environmental assessment results indicated the supercritical process, even when working at a 42:1 molar ratio, has a lower output PEI per mass of product than the conventional base catalyzed process. The supercritical process working at a 9:1 molar ratio and 400 C had the lowest PEI per mass of product. This can be attributed to reduced energy consumption and the possibility of producing more biofuel through glycerol decomposition reactions that form ethers, which have the potential to be used as part of the fuel.
Energy & Fuels, 2010
ABSTRACT
Journal of Supercritical Fluids, 2010
Batch experiments on chicken fat reactions with methanol were performed at supercritical conditio... more Batch experiments on chicken fat reactions with methanol were performed at supercritical conditions to answer basic questions regarding the transesterification characteristics such as reactant ratios, lipid and reaction product thermal stability, reaction reversibility, nature of the intermediates, and glycerol consumption. The experiments were conducted at temperatures of 300–400°C, pressures up to 41.1MPa, methanol to triglyceride molar ratios of 3:1 and
Journal of Supercritical Fluids, 2010
... Although this process has for decades been thought to cause increased emissions of PCDD/PCDFs... more ... Although this process has for decades been thought to cause increased emissions of PCDD/PCDFs, Karstensen [16] reports a great deal of experimental data of PCDD/PCDFs measurements by the cement industry that do not support this perception, and indicates that most ...
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Papers by Victor Marulanda