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Records with Subject: Reaction Engineering
Showing records 264 to 288 of 288. [First] Page: 1 8 9 10 11 12 Last
Generation of Hydrogen, Lignin and Sodium Hydroxide from Pulping Black Liquor by Electrolysis
Guangzai Nong, Zongwen Zhou, Shuangfei Wang
October 22, 2018 (v1)
Keywords: black liquor, electrolysis, Energy, Hydrogen, lignin
Black liquor is generated in Kraft pulping of wood or non-wood raw material in pulp mills, and regarded as a renewable resource. The objective of this paper was to develop an effective means to remove the water pollutants by recovery of both lignin and sodium hydroxide from black liquor, based on electrolysis. The treatment of a 1000 mL of black liquor (122 g/L solid contents) consumed 345.6 kJ of electric energy, and led to the generation of 30.7 g of sodium hydroxide, 0.82 g of hydrogen gas and 52.1 g of biomass solids. Therefore, the recovery ratios of elemental sodium and biomass solids are 80.4% and 76%, respectively. Treating black liquor by electrolysis is an environmentally friendly technology that can, in particular, be an alternative process in addressing the environmental issues of pulping waste liquor to the small-scale mills without black liquor recovery.
Low-Cost Feedstock Conversion to Biodiesel via Ultrasound Technology
Omotola Babajide, Leslie Petrik, Bamikole Amigun, Farouk Ameer
October 22, 2018 (v1)
Keywords: biodiesel, conversion efficiency, glycerol, transesterification, ultrasound
Biodiesel has attracted increasing interest and has proved to be a good substitute for fossil-based fuels due to its environmental advantages and availability from renewable resources such as refined and waste vegetable oils. Several studies have shown that biodiesel is a better fuel than the fossil-derived diesel in terms of engine performance, emissions reduction, lubricity and environmental benefits. The increasing popularity of biodiesel has generated great demand for its commercial production methods, which in turn calls for the development of technically and economically sound process technologies. This paper explores the applicability of ultrasound in the optimization of low-cost feedstock ⁻ in this case waste cooking oil ⁻ in the transesterification conversion to biodiesel. It was found that the conversion efficiency of the waste oil using ultrasound was higher than with the mechanical stirring method. The optimized variables of 6:1 methanol/oil ratio at a reaction temperature... [more]
Recent Advances in Direct Coal Liquefaction
Hengfu Shui, Zhenyi Cai, Chunbao Xu
October 22, 2018 (v1)
Keywords: Biomass, catalysts, co-liquefaction, coal pre-treatment, direct coal liquefaction (DCL), influencing factors, processes
The growing demand for petroleum, accompanied by the declining petroleum reserves and the concerns over energy security, has intensified the interest in direct coal liquefaction (DCL), particularly in countries such as China which is rich in coal resources, but short of petroleum. In addition to a general introduction on the mechanisms and processes of DCL, this paper overviews some recent advances in DCL technology with respect to the influencing factors for DCL reactions (temperature, solvent, pressure, atmospheres, etc.), the effects of coal pre-treatments for DCL (swelling, thermal treatment, hydrothermal treatment, etc.), as well as recent development in multi-staged DCL processes, DCL catalysts and co-liquefaction of coal with biomass.
Esterification of Oleic Acid for Biodiesel Production Catalyzed by SnCl₂: A Kinetic Investigation
Abiney L. Cardoso, Soraia Cristina Gonzaga Neves, Marcio J. Da Silva
October 15, 2018 (v1)
Keywords: Biodiesel, ethanolysis, free fatty acids, Tin chloride catalyst
The production of biodiesel from low-cost raw materials which generally contain high amounts of free fatty acids (FFAs) is a valuable alternative that would make their production costs more competitive than petroleum-derived fuel. Currently, the production of biodiesel from this kind of raw materials comprises a two-stage process, which requires an initial acid-catalyzed esterification of the FFA, followed by a basecatalyzed transesterification of the triglycerides. Commonly, the acid H₂SO₄ is the catalyst on the first step of this process. It must be said, however, that major drawbacks such as substantial reactor corrosion and the great generation of wastes, including the salts formed due to neutralization of the mineral acid, are negative and virtually unsurmountable aspects of this protocol. In this paper, tin(II) chloride dihydrate (SnCl₂·2H₂O), an inexpensive Lewis acid, was evaluated as catalyst on the ethanolysis of oleic acid, which is the major component of several fat and veg... [more]
Waste Cooking Oil as an Alternate Feedstock for Biodiesel Production
Arjun B. Chhetri, K. Chris Watts, M. Rafiqul Islam
October 15, 2018 (v1)
Keywords: alternate energy, biodiesel, feedstock, fuel characterization, Waste cooking oil
As crude oil price reach a new high, the need for developing alternate fuels has become acute. Alternate fuels should be economically attractive in order to compete with currently used fossil fuels. In this work, biodiesel (ethyl ester) was prepared from waste cooking oil collected from a local restaurant in Halifax, Nova Scotia, Canada. Ethyl alcohol with sodium hydroxide as a catalyst was used for the transesterification process. The fatty acid composition of the final biodiesel esters was determined by gas chromatography. The biodiesel was characterized by its physical and fuel properties including density, viscosity, acid value, flash point, cloud point, pour point, cetane index, water and sediment content, total and free glycerin content, diglycerides and monoglycerides, phosphorus content and sulfur content according to ASTM standards. The viscosity of the biodiesel ethyl ester was found to be 5.03 mm²/sec at 40oC. The viscosity of waste cooking oil measured in room temperature (... [more]
Combustion Characteristics and NOx Emission through a Swirling Burner with Adjustable Flaring Angle
Yafei Zhang, Rui Luo, Yihua Dou, Qulan Zhou
September 21, 2018 (v1)
Keywords: combustion adjustment, flaring angle, fuel rich/lean combustion, low load, swirling burner
A swirling burner with a variable inner secondary air (ISA) flaring angle β is proposed and a laboratory scale opposed-firing furnace is built. Temperature distribution and NOx emission are designedly measured. The combustion characteristics affected by variable β are experimentally evaluated from ignition and burnout data. Meanwhile, NOx reduction by the variable β is analyzed through emissions measurements. Different inner/outer primary coal-air concentration ratios γ, thermal loads and coal types are considered in this study. Results indicate that β variation provides a new approach to promote ignition and burnout, as well as NOx emission reduction under conditions of fuel rich/lean combustion and load variation. The recommended β of a swirling burner under different conditions is not always constant. The optimal βopt of the swirling burner under all conditions for different burning performance are summarized in the form of curves, which could provide reference for exquisite combust... [more]
Autoignition Behavior of an Ethanol-Methylcellulose Gel Droplet in a Hot Environment
Donggi Lee, Jonghan Won, Seung Wook Baek, Hyemin Kim
September 21, 2018 (v1)
Keywords: autoignition, combustion, droplet, Ethanol, gel propellant
Autoignition of an ethanol-based gel droplet was experimentally investigated by adding 10 wt % of methylcellulose as gellant to liquid ethanol. Experimental studies of the ignition behavior of the gel droplet were found to be quite rare. The initial droplet diameter was 1.17 ± 0.23 mm. The gel droplet was suspended on a K-type thermocouple and its evaporation, ignition and combustion characteristics were evaluated and compared with pure ethanol at an ambient temperature of 600, 700, and 800 °C under atmospheric pressure conditions. The gel droplet exhibited swelling and vapor jetting phenomena. Before ignition, a linear decrease in droplet diameter followed by a sudden increase was repeatedly observed, which was caused by evaporation and swelling processes, respectively. Major droplet swelling was detected just before the onset of ignition at all temperatures. But no further swelling was detected after ignition. For the gel droplet, the ignition delay accounted for 93% of the droplet l... [more]
Migration and Transformation of Vanadium and Nickel in High Sulfur Petroleum Coke during Gasification Processes
Wei Li, Ben Wang, Jun Nie, Wu Yang, Linlin Xu, Lushi Sun
September 21, 2018 (v1)
Keywords: gasification, high sulfur petcoke, migration, nickel, sequential extraction, vanadium
The volatilization characteristics and occurrence forms of V and Ni in petroleum coke (petcoke) were investigated during steam (H₂O) and carbon dioxide (CO₂) gasification on a fixed bed reactor at 800⁻1100 °C. The Tessier sequential chemical extraction procedure was employed to determine the different forms of V and Ni. The results showed their volatilities were not dependent on the gasification atmosphere, but rather relied mainly on the reaction temperature. The CO₂ atmosphere accelerated the conversion of organic-bound nickel to residual form at low temperature and promoted Fe-Mn oxides formation at high temperature. However, the H₂O atmosphere was conducive to form vanadium bound to Fe-Mn oxides and promoted the decomposition of residual forms. In addition, the thermodynamic equilibrium calculations showed the volatilization of Ni mainly released Ni₃S₂ between 800⁻1100 °C. The H₂O atmosphere was favorable to generate the more stable NixSy compound, thereby suppressing the volatiliz... [more]
Nitric Acid Pretreatment of Jerusalem Artichoke Stalks for Enzymatic Saccharification and Bioethanol Production
Urszula Dziekońska-Kubczak, Joanna Berłowska, Piotr Dziugan, Piotr Patelski, Katarzyna Pielech-Przybylska, Maria Balcerek
September 21, 2018 (v1)
Keywords: acid pretreatment, alkali pretreatment, enzymatic hydrolysis, ethanol fermentation, Jerusalem artichoke, lignocellulose, nitric acid
This paper evaluated the effectiveness of nitric acid pretreatment on the hydrolysis and subsequent fermentation of Jerusalem artichoke stalks (JAS). Jerusalem artichoke is considered a potential candidate for producing bioethanol due to its low soil and climate requirements, and high biomass yield. However, its stalks have a complexed lignocellulosic structure, so appropriate pretreatment is necessary prior to enzymatic hydrolysis, to enhance the amount of sugar that can be obtained. Nitric acid is a promising catalyst for the pretreatment of lignocellulosic biomass due to the high efficiency with which it removes hemicelluloses. Nitric acid was found to be the most effective catalyst of JAS biomass. A higher concentration of glucose and ethanol was achieved after hydrolysis and fermentation of 5% (w/v) HNO₃-pretreated JAS, leading to 38.5 g/L of glucose after saccharification, which corresponds to 89% of theoretical enzymatic hydrolysis yield, and 9.5 g/L of ethanol. However, after f... [more]
Combustion of Flax Shives, Beech Wood, Pure Woody Pseudo-Components and Their Chars: A Thermal and Kinetic Study
Nourelhouda Boukaous, Lokmane Abdelouahed, Mustapha Chikhi, Abdeslam-Hassen Meniai, Chetna Mohabeer, Taouk Bechara
September 21, 2018 (v1)
Keywords: Biomass, combustion, kinetic parameters, thermal characteristics, thermogravimetric analysis
Thermogravimetric analysis was employed to investigate the combustion characteristics of flax shives, beech wood, hemicellulose, cellulose, lignin, and their chars. The chars were prepared from raw materials in a fixed-bed reactor at 850 °C. In this study, the thermal behavior based on characteristic temperatures (ignition, maximum, and final temperatures), burnout time and maximum rate was investigated. The kinetic parameters for the combustion of different materials were determined based on the Coats-Redfern approach. The results of our study revealed that the combustion of pure pseudo-components behaved differently from that of biomass. Indeed, principal component analysis showed that the thermal behavior of both biomasses was generally similar to that of pure hemicellulose. However, pure cellulose and lignin showed different behaviors compared to flax shives, beech wood, and hemicellulose. Hemicellulose and cellulose chars had almost the same behaviors, while being different from b... [more]
Experimental Study of a Bubble Mode Absorption with an Inner Vapor Distributor in a Plate Heat Exchanger-Type Absorber with NH₃-LiNO₃
Jorge J. Chan, Roberto Best, Jesús Cerezo, Mario A. Barrera, Francisco R. Lezama
September 21, 2018 (v1)
Keywords: absorption cooling, ammonia-lithium nitrate, bubble absorber, plate heat exchanger
Absorption systems are a sustainable solution as solar driven air conditioning devices in places with warm climatic conditions, however, the reliability of these systems must be improved. The absorbing component has a significant effect on the cycle performance, as this process is complex and needs efficient heat exchangers. This paper presents an experimental study of a bubble mode absorption in a plate heat exchanger (PHE)-type absorber with NH₃-LiNO₃ using a vapor distributor in order to increase the mass transfer at solar cooling operating conditions. The vapor distributor had a diameter of 0.005 m with five perforations distributed uniformly along the tube. Experiments were carried out using a corrugated plate heat exchanger model NB51, with three channels, where the ammonia vapor was injected in a bubble mode into the solution in the central channel. The range of solution concentrations and mass flow rates of the dilute solution were from 35 to 50% weight and 11.69 to 35.46 × 10−... [more]
Biodiesel Production from Palm Oil, Its By-Products, and Mill Effluent: A Review
Khairul Azly Zahan, Manabu Kano
September 21, 2018 (v1)
Keywords: biodiesel, by-products, mill effluent, palm oil, properties, sustainability
The sustainability of petroleum-based fuel supply has gained broad attention from the global community due to the increase of usage in various sectors, depletion of petroleum resources, and uncertain around crude oil market prices. Additionally, environmental problems have also arisen from the increasing emissions of harmful pollutants and greenhouse gases. Therefore, the use of clean energy sources including biodiesel is crucial. Biodiesel is mainly produced from unlimited natural resources through a transesterification process. It presents various advantages over petro-diesel; for instance, it is non-toxic, biodegradable, and contains less air pollutant per net energy produced with low sulphur and aromatic content, apart from being safe. Considering the importance of this topic, this paper focuses on the use of palm oil, its by-products, and mill effluent for biodiesel production. Palm oil is known as an excellent raw material because biodiesel has similar properties to the regular p... [more]
The Influence of Char Preparation and Biomass Type on Char Steam Gasification Kinetics
Tilia Dahou, Françoise Defoort, Sébastien Thiéry, Maguelone Grateau, Matthieu Campargue, Simona Bennici, Mejdi Jeguirim, Capucine Dupont
September 21, 2018 (v1)
Keywords: Biomass, characteristic time analysis, kinetics, pyrolysis conditions, steam gasification, thermogravimetric analysis
A study was conducted to investigate the parameter that has influence on steam gasification kinetics between the biomass type and char preparation. Thermogravimetric analysis (TGA) was carried out on steam gasification of seven biomass samples as well as chars from three of these samples. Chars were prepared using three different sets of low heating rate (LHR) pyrolysis conditions including temperature and biomass bed geometry. It was shown by a characteristic time analysis that these pyrolysis conditions were not associated with a chemical regime in a large amount of devices. However, it has been shown experimentally that conditions used to prepare the char had a much lower influence on steam gasification kinetics than the biomass type.
Enhancing Biochemical Methane Potential and Enrichment of Specific Electroactive Communities from Nixtamalization Wastewater using Granular Activated Carbon as a Conductive Material
David Valero, Carlos Rico, Blondy Canto-Canché, Jorge Arturo Domínguez-Maldonado, Raul Tapia-Tussell, Alberto Cortes-Velazquez, Liliana Alzate-Gaviria
September 21, 2018 (v1)
Keywords: biochemical methane potential, direct interspecies electron transfer, electroactive biofilm, granular activated carbon, Nejayote, redox potential reduction
Nejayote (corn step liquor) production in Mexico is approximately 1.4 × 1010 m³ per year and anaerobic digestion is an effective process to transform this waste into green energy. The biochemical methane potential (BMP) test is one of the most important tests for evaluating the biodegradability and methane production capacity of any organic waste. Previous research confirms that the addition of conductive materials significantly enhances the methane production yield. This study concludes that the addition of granular activated carbon (GAC) increases methane yield by 34% in the first instance. Furthermore, results show that methane production is increased by 54% when a GAC biofilm is developed 10 days before undertaking the BMP test. In addition, the electroactive population was 30% higher when attached to the GAC than in control reactors. Moreover, results show that electroactive communities attached to the GAC increased by 38% when a GAC biofilm is developed 10 days before undertaking... [more]
The Efficiency of Nitrogen and Flue Gas as Operating Gases in Explosive Decompression Pretreatment
Merlin Raud, Vahur Rooni, Timo Kikas
September 21, 2018 (v1)
Keywords: bioethanol, lignocellulose, mass balance, pretreatment, second generation biofuel
As the pretreatment process is the most expensive and energy-consuming step in the overall second generation bioethanol production process, it is vital that it is studied and optimized in order to be able to develop the most efficient production process. The aim of this paper was to investigate chemical and physical changes in biomass during the process of applying the explosive decompression pretreatment method using two different gases—N₂ and synthetic flue gas. The explosive decompression method is economically and environmentally attractive since no chemicals are used—rather it is pressure that is applied—and water is used to break down the biomass structure. Both pre-treatment methods were used at different temperatures. To be able to compare the effects of the pretreatment, samples from different process steps were gathered together and analysed. The results were used to assess the efficiency of the pretreatment, the chemical and physical changes in the biomass and, finally, the... [more]
Thermophilic Anaerobic Digestion: Enhanced and Sustainable Methane Production from Co-Digestion of Food and Lignocellulosic Wastes
Aditi David, Tanvi Govil, Abhilash Kumar Tripathi, Julie McGeary, Kylie Farrar, Rajesh Kumar Sani
September 21, 2018 (v1)
Keywords: corn stover, digester performance, Methanothermobacter, microbial community, prairie cord grass, process stability, synergistic effects, thermophilic anaerobic digestion, unbleached paper
This article aims to study the codigestion of food waste (FW) and three different lignocellulosic wastes (LW) (Corn stover (CS), Prairie cordgrass (PCG), and Unbleached paper (UBP)) for thermophilic anaerobic digestion to overcome the limitations of digesting food waste alone (volatile fatty acids accumulation and low C:N ratio). Using an enriched thermophilic methanogenic consortium, all the food and lignocellulosic waste mixtures showed positive synergistic effects of codigestion. After 30 days of incubation at 60 °C (100 rpm), the highest methane yield of 305.45 L·kg−1 volatile solids (VS) was achieved with a combination of FW-PCG-CS followed by 279.31 L·kg−1 VS with a mixture of FW-PCG. The corresponding volatile solids reduction for these two co-digestion mixtures was 68% and 58%, respectively. This study demonstrated a reduced hydraulic retention time for methane production using FW and LW.
Macroscopic and Microscopic Spray Characteristics of Diesel and Gasoline in a Constant Volume Chamber
Moo-Yeon Lee, Gee-Soo Lee, Chan-Jung Kim, Jae-Hyeong Seo, Ki-Hyun Kim
September 21, 2018 (v1)
Keywords: Diesel, Gasoline, liquid penetration, microscopic spray visualization, vapor penetration
The aim of this study is to investigate the spray characteristics of diesel and gasoline under various ambient conditions. Ambient conditions were simulated, ranging from atmospheric conditions to high pressure and temperature conditions such as those inside a combustion chamber of an internal combustion engine. Spray tip penetration and spray cross-sectional area were calculated in liquid and vapor spray development. In addition, initial spray development and end of injection near nozzle were visualized microscopically, to study spray atomization characteristics. Three injection pressures of 50 MPa, 100 MPa, and 150 MPa were tested. The ambient temperature was varied from 300 K to 950 K, and the ambient density was maintained between 1 kg/m³ and 20 kg/m³. Gasoline and diesel exhibited similar liquid penetration and spray cross-sectional area at every ambient density condition under non-evaporation. As the ambient temperature increased, liquid penetration length and spray area of both... [more]
Lifetime Prediction of a Polymer Electrolyte Membrane Fuel Cell under Automotive Load Cycling Using a Physically-Based Catalyst Degradation Model
Manik Mayur, Mathias Gerard, Pascal Schott, Wolfgang G. Bessler
September 21, 2018 (v1)
Keywords: catalyst degradation, driving cycle, durability estimation, Modelling, polymer electrolyte membrane fuel cell (PEMFC)
One of the bottlenecks hindering the usage of polymer electrolyte membrane fuel cell technology in automotive applications is the highly load-sensitive degradation of the cell components. The cell failure cases reported in the literature show localized cell component degradation, mainly caused by flow-field dependent non-uniform distribution of reactants. The existing methodologies for diagnostics of localized cell failure are either invasive or require sophisticated and expensive apparatus. In this study, with the help of a multiscale simulation framework, a single polymer electrolyte membrane fuel cell (PEMFC) model is exposed to a standardized drive cycle provided by a system model of a fuel cell car. A 2D multiphysics model of the PEMFC is used to investigate catalyst degradation due to spatio-temporal variations in the fuel cell state variables under the highly transient load cycles. A three-step (extraction, oxidation, and dissolution) model of platinum loss in the cathode cataly... [more]
Production of Hydrogen by Methane Steam Reforming Coupled with Catalytic Combustion in Integrated Microchannel Reactors
Junjie Chen, Baofang Liu, Xuhui Gao, Deguang Xu
September 21, 2018 (v1)
Keywords: catalytic combustion, Computational Fluid Dynamics, hydrogen production, Process Intensification, process optimization, Steam Reforming, thermal management, thermally integrated microchannel reactors
This paper addresses the issues related to the rapid production of hydrogen from methane steam reforming by means of process intensification. Methane steam reforming coupled with catalytic combustion in thermally integrated microchannel reactors for the production of hydrogen was investigated numerically. The effect of the catalyst, flow arrangement, and reactor dimension was assessed to optimize the design of the system. The thermal interaction between reforming and combustion was investigated for the purpose of the rapid production of hydrogen. The importance of thermal management was discussed in detail, and a theoretical analysis was made on the transport phenomena during each of the reforming and combustion processes. The results indicated that the design of a thermally integrated system operated at millisecond contact times is feasible. The design benefits from the miniaturization of the reactors, but the improvement in catalyst performance is also required to ensure the rapid pr... [more]
Hydrothermal Carbonization of Fruit Wastes: A Promising Technique for Generating Hydrochar
Bide Zhang, Mohammad Heidari, Bharat Regmi, Shakirudeen Salaudeen, Precious Arku, Mahendra Thimmannagari, Animesh Dutta
September 21, 2018 (v1)
Keywords: characterization, energy density, fruit waste, hydrothermal carbonization, mass yield
Hydrothermal carbonization (HTC) is a useful method to convert wet biomass to value-added products. Fruit waste generated in juice industries is a huge source of moist feedstock for such conversion to produce hydrochar. This paper deals with four types of fruit wastes as feedstocks for HTC; namely, rotten apple (RA), apple chip pomace (ACP), apple juice pomace (AJP), and grape pomace (GP). The operating conditions for HTC processing were 190 °C, 225 °C, and 260 °C for 15 min. For all samples, higher heating value and fixed carbon increased, while volatile matter and oxygen content decreased after HTC. Except for ACP, the ash content of all samples increased after 225 °C. For RA, AJP, and GP, the possible explanation for increased ash content above 225 °C is that the hydrochar increases in porosity after 230 °C. It was observed that an increase in HTC temperature resulted in an increase in the mass yield for RA and GP, which is in contrast with increasing HTC temperature for lignocellul... [more]
Experimental Study of Mixed Gas Hydrates from Gas Feed Containing CH₄, CO₂ and N₂: Phase Equilibrium in the Presence of Excess Water and Gas Exchange
Ludovic Nicolas Legoix, Livio Ruffine, Christian Deusner, Matthias Haeckel
September 21, 2018 (v1)
Keywords: Carbon Dioxide, CH4, gas exchange, gas hydrates, high-pressure experiments, N2, phase equilibrium
This article presents gas hydrate experimental measurements for mixtures containing methane (CH₄), carbon dioxide (CO₂) and nitrogen (N₂) with the aim to better understand the impact of water (H₂O) on the phase equilibrium. Some of these phase equilibrium experiments were carried out with a very high water-to-gas ratio that shifts the gas hydrate dissociation points to higher pressures. This is due to the significantly different solubilities of the different guest molecules in liquid H₂O. A second experiment focused on CH₄-CO₂ exchange between the hydrate and the vapor phases at moderate pressures. The results show a high retention of CO₂ in the gas hydrate phase with small pressure variations within the first hours. However, for our system containing 10.2 g of H₂O full conversion of the CH₄ hydrate grains to CO₂ hydrate is estimated to require 40 days. This delay is attributed to the shrinking core effect, where initially an outer layer of CO₂-rich hydrate is formed that effectively s... [more]
Possible Interactions and Interferences of Copper, Chromium, and Arsenic during the Gasification of Contaminated Waste Wood
Shurooq Badri Al-Badri, Ying Jiang, Stuart Thomas Wagland
September 21, 2018 (v1)
Keywords: Boudouard reaction in gasification, interactions, interferences, MTDATA, partial combustion reaction in gasification, waste wood
A considerable proportion (about 64%) of biomass energy is produced from woody biomass (wood and its wastes). However, waste wood (WW) is very often contaminated with metal(loid) elements at concentrations leading to toxicity emissions and damages to facilities during thermal conversion. Therefore, procedures for preventing and/or alleviating the negative impacts of these elements require further development, particularly by providing informative and supportive information regarding the phase transformations of the metal(loid)s during thermal conversion processes. Although it is well known that phase transformation depends on different factors such as elements’ vaporization characteristics, operational conditions, and process configuration; however, the influences of reaction atmosphere composition in terms of interactions and interferences are rarely addressed. In response, since Cu, Cr, and As (CCA-elements) are the most regulated elements in woody biomass, this paper aims to explore... [more]
Investigation of the Olive Mill Solid Wastes Pellets Combustion in a Counter-Current Fixed Bed Reactor
Mohamed Ali Mami, Hartmut Mätzing, Hans-Joachim Gehrmann, Dieter Stapf, Rainer Bolduan, Marzouk Lajili
September 21, 2018 (v1)
Keywords: combustion parameters, fixed bed combustor, gaseous emissions, olive mill solid wastes (OMSWs), pellets
Combustion tests and gaseous emissions of olive mill solid wastes pellets (olive pomace (OP), and olive pits (OPi)) were carried out in an updraft counter-current fixed bed reactor. Along the combustion chamber axis and under a constant primary air flow rate, the bed temperatures and the mass loss rate were measured as functions of time. Moreover, the gas mixture components such as O₂, organic carbon (Corg), CO, CO₂, H₂O, H₂, SO₂, and NOx (NO + NO₂) were analyzed and measured. The reaction front positions were determined as well as the ignition rate and the reaction front velocity. We have found that the exhaust gases are emitted in acceptable concentrations compared to the combustion of standard wood pellets reported in the literature (EN 303-5). It is shown that the bed temperature increased from the ambient value to a maximum value ranging from 750 to 1000 °C as previously reported in the literature. The results demonstrate the promise of using olive mill solid waste pellets as an a... [more]
Correction: Study of n-Butyl Acrylate Self-Initiation Reaction Experimentally and via Macroscopic Mechanistic Modeling Processes 2016, 4, 15
Ahmad Arabi Shamsabadi, Nazanin Moghadam, Sriraj Srinivasan, Patrick Corcoran, Michael C. Grady, Andrew M. Rappe, Masoud Soroush
July 30, 2018 (v1)
Keywords: 10.3390/pr4020015, doi
We wish to correct Table 5 of the published paper in Processes [1].[...]
Study of n-Butyl Acrylate Self-Initiation Reaction Experimentally and via Macroscopic Mechanistic Modeling
Ahmad Arabi Shamsabadi, Nazanin Moghadam, Sriraj Srinivasan, Patrick Corcoran, Michael C. Grady, Andrew M. Rappe, Masoud Soroush
July 30, 2018 (v1)
Keywords: free-radical polymerization, method of moments, monomer self-initiation, n-butyl acrylate, spontaneous thermal polymerization
This paper presents an experimental study of the self-initiation reaction of n-butyl acrylate (n-BA) in free-radical polymerization. For the first time, the frequency factor and activation energy of the monomer self-initiation reaction are estimated from measurements of n-BA conversion in free-radical homo-polymerization initiated only by the monomer. The estimation was carried out using a macroscopic mechanistic mathematical model of the reactor. In addition to already-known reactions that contribute to the polymerization, the model considers a n-BA self-initiation reaction mechanism that is based on our previous electronic-level first-principles theoretical study of the self-initiation reaction. Reaction rate equations are derived using the method of moments. The reaction-rate parameter estimates obtained from conversion measurements agree well with estimates obtained via our purely-theoretical quantum chemical calculations.
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