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1.
  • Ahmad, Waqar, et al. (författare)
  • Investigation of different configurations of alumina packed bed reactor for coke free conversion of benzene
  • 2024
  • Ingår i: Chemical engineering research & design. - : Elsevier. - 0263-8762 .- 1744-3563. ; 201, s. 433-445
  • Tidskriftsartikel (refereegranskat)abstract
    • Conversion of producer gas tar without coke generation is a great challenge. This study investigates conversion of tar model benzene using different configurations of highly non-porous ɣ-Al2O3 packed bed reactor at 1000–1100 0C. The configurations comprised of different positions (relative to top (P1), center (P2) and bottom (P3) of reactor furnace), heights (5, 13 and 25 cm) and particles sizes (0.5, 3 and 5 mm) of alumina packed bed. Steam and CO2 were used as reforming media for tested benzene concentrations (0.4–1.8 vol%). The results showed benzene conversions of 48–91% with negligible steady thin coke generation using a packed bed (height: 25 cm, particles size: 3 mm) at P1. Whereas, relative high benzene conversions of 63–93 and 68–95% at P2 and P3 respectively with unsteady thick coke generation at benzene concentrations greater than 0.4 vol% increased differential upstream pressures (DUPs) of beds. Similar unsteady coke generation at benzene concentrations greater than 0.8 vol% and temperature of 1100 0C was observed with packed beds of heights of 5 and 13 cm, and particles size of 0.5 mm at P1. Generation of unsteady coke with condensed structure as evidenced by its characterization was attributable to increased benzene polymerization and reduced bed surface gasification reactions due to improperly installed packed bed. Developed kinetic model predicted well the generated coke. As conclusion, properly installed alumina packed bed pertaining to tar concentration and other experimental conditions may inhibit coke generation during tar conversion.
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2.
  • Albero Caro, Jesus, et al. (författare)
  • Semibatch reaction crystallization of salicylic acid
  • 2014
  • Ingår i: Chemical engineering research & design. - : Elsevier BV. - 0263-8762 .- 1744-3563. ; 92:3, s. 522-533
  • Tidskriftsartikel (refereegranskat)abstract
    • Reaction crystallization of salicylic acid has been investigated by experiments and modeling. In the experimental work, dilute hydrochloric acid has been added to an agitated aqueous solution of sodium salicylate in 1 L scale, and product crystals have been characterized by image analysis. The results show that the product crystal number mean size at first increases with increasing agitation rate but then gradually decreases again at further increase in stirring rate. At lower stirring rate, larger crystals are obtained when the feeding point is located close to the agitator instead of being located out in the bulk solution. The mean crystal size increases with decreasing feeding rate and with decreasing reactant concentrations. There is a decrease in mean size with increasing feed pipe diameter. These trends in the experimental results show great similarity with previous results on benzoic acid. The experimental results have been examined by a population balance model accounting for meso and micro mixing, and crystal nucleation and growth rate dispersion. It is found that the crystallization kinetic parameter estimation is quite complex, and the objective function hyper surface contains many different minima. Hence, parameter estimation has to rely on a combination of mathematical optimization strategies and a scientific understanding of the physical meaning of the parameters and their relation to current theories. As opposed to our previous work on benzoic acid, it has not been possible to find a set of kinetic parameters that provides for a good description of all experimental data.
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3.
  • Arvidsson, Maria, 1984, et al. (författare)
  • Comparative thermodynamic analysis of biomass gasification-based light olefin production using methanol or DME as the platform chemical
  • 2016
  • Ingår i: Chemical Engineering Research and Design. - : Elsevier BV. - 0263-8762 .- 1744-3563. ; 115, s. 182-194
  • Tidskriftsartikel (refereegranskat)abstract
    • This work investigates and compares the thermodynamic performance of alternative platform chemicals for the production of light olefins (i.e., ethylene, propylene, and mixed butylenes) via gasification of lignocellulosic biomass (forest residues). Two concepts based on the same general process layout are considered: (i) via methanol synthesis and methanol-to-olefins (MTO) synthesis; (ii) via direct dimethyl ether (DME) synthesis and DME-to-olefins (DTO) synthesis. The work is based on process models established in Aspen Plus to obtain mass and energy balances. Heat recovery targets for integration of a steam network for combined heat and power production are investigated using pinch analysis tools. The different process alternatives are compared in terms of energy efficiency. Additionally, to identify key process differences, the cold gas efficiency and carbon conversion from biomass feedstock to various intermediate products along the process value chain are compared. The results show that light olefins could be produced with an energy efficiency of approximately 52–54% (higher heating value (HHV) basis) using methanol and DME as platform chemicals. The two investigated concepts had similar cold gas efficiency along the process value chain and overall electricity balance. Accordingly, no significant thermodynamic difference could be identified for the two investigated cases. One interesting feature that is identified is that the same amount of the renewable carbon in the feedstock is lost, mainly as CO2, regardless of whether the methanol or DME route is adopted. The difference is where in the process value chain most of the CO2 is formed and removed.
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4.
  • Azis, Muhammad Mufti, 1983, et al. (författare)
  • On evaluation of synthetic and natural ilmenite using syngas as fuel in chemical-looping combustion (CLC)
  • 2010
  • Ingår i: Chemical Engineering Research and Design. - : Elsevier BV. - 0263-8762 .- 1744-3563. ; 88:11A, s. 1505-1514
  • Tidskriftsartikel (refereegranskat)abstract
    • Chemical-looping combustion (CLC) is a combustion technique where the CO2 produced is inherently separated fromthe rest of the flue gases with a considerably low energy penalty. For this reason, CLC has emerged as one of the moreattractive options to capture CO2 from fossil fuel combustion. When applying CLC with solid fuels, the use of a lowcost oxygen carrier is highly important, and one such low cost oxygen carrier is the mineral ilmenite. The currentwork investigates the reactivity of several ilmenites, some which are synthetically produced by freeze granulationand two natural minerals, one Norwegian ilmenite and one South African ilmenite.A laboratory fluidized bed reactor made of quartz was used to simulate a two reactor CLC system by alternatingthe reduction and oxidation phase. The fuel was syngas containing 50% CO and 50% H2. A mixture of 6 g of ilmenitewith 9 g inert quartz of diameter 125–180μm was exposed to a flow of 900mLn/min syngas in the reduction phase.During the oxidation phase, a 900mLn/min flow of 10% O2 diluted in N2 was used.The experimental results showed that all ilmenites give higher conversion of H2 than of CO. Generally, syntheticilmenites have better CO and H2 conversion than natural ilmenites and synthetic ilmenites prepared with an excessof Fe generally showed higher total conversion of CO than synthetic ilmenites with an excess of Ti. Most syntheticilmenites and the Norwegian ilmenite showed good fluidization properties during the experiments. However, for twoof the synthetically produced materials, and for the South African ilmenite, particle agglomerations were visible atthe end of the experiment.
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5.
  • Bebelis, S., et al. (författare)
  • Highlights during the development of electrochemical engineering
  • 2013
  • Ingår i: Chemical engineering research & design. - : Elsevier BV. - 0263-8762 .- 1744-3563. ; 91:10, s. 1998-2020
  • Tidskriftsartikel (refereegranskat)abstract
    • Over the last century, electrochemical engineering has contributed significantly to societal progress by enabling development of industrial processes for manufacturing chemicals, such as chlorine and the Nylon precursor adiponitrile, as well as a wide range of metals including aluminium and zinc. In 2011, ca. 17 M tonne Cu p.a. was electro-refined to 99.99%+ purity required by electrical and electronic engineering applications, such as for electrodepositing with exquisite resolution multi-layer inter-connections in microprocessors. Surface engineering is widely practised industrially e.g. to protect steels against corrosion e.g. by electroplating nickel or using more recent novel self-healing coatings. Complex shapes of hard alloys that are difficult to machine can be fabricated by selective dissolution in electrochemical machining processes. Electric fields can be used to drive desalination of brackish water for urban supplies and irrigation by electrodialysis with ion-permeable membranes; such fields can also be used in electrokinetic soil remediation processes. Rising concerns about the consequences of CO2 emissions has led to the rapidly increasing development and deployment of renewable energy systems, the intermittency of which can be mitigated by energy storage in e.g. redox flow batteries for stationary storage and novel lithium batteries with increased specific energies for powering electric vehicles, or when economically viable, in electrolyser-fuel cells. The interface between electrochemical technology and biotechnology is also developing rapidly, with applications such as microbial fuel cells.Some of these applications are reviewed, the challenges assessed and current trends elucidated in the very active area of Chemical Engineering bordering with material science and electrochemistry.
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6.
  • Bijok, Nicolaus, et al. (författare)
  • Chip scale modelling of the kraft pulping process by considering the heterogeneous nature of the lignocellulosic feedstock
  • 2023
  • Ingår i: Chemical engineering research & design. - : Elsevier BV. - 0263-8762 .- 1744-3563. ; 193, s. 13-27
  • Tidskriftsartikel (refereegranskat)abstract
    • This article focuses on a multiscale modelling approach to describe the delignification of softwood during the kraft pulping process. A framework for modelling the lignocellulosic feedstock on a fibre scale which considered the fundamental chemical components of wood as a distributed variable is re-assessed and extended to include chip-level phenomena such as diffusion limitations and initial component distributions within a softwood chip mixture. A new description of the wood chip is presented using a finite volume discretisation along one spatial dimension by simultaneously considering the anisotropic structural differences of the wood. Additionally, based on literature data, a distinction between the softwood chips' early- and latewood regions with their differences in densities and chemical composition is suggested. The presented model framework uses published sub-models for kinetics, diffusion etc. The validation and estimation of the remaining parameters are conducted from experimental data that quantifies the kappa number distribution of individual softwood fibres after kraft pulping. The investigation hypothesises a Gaussian distribution for the initial chemical component distribution within wood chips from a well-defined region. In contrast, a Log-normal distribution is used to describe the initial chemical distribution within a softwood chip mixture. The established sub-models for the kraft pulping process's kinetics and mass transfer phenomena could not predict the experimental data satisfactorily. However, modifying the sub-models by including a change in lignin reactivity and a temperature dependency of the lignin reactivity decline during the delignification progress could predict the essence of the observed experimental kappa number distribution. 
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7.
  • Bouaifi, M., et al. (författare)
  • Experimental and numerical investigations of jet mixing in a multifunctional channel reactor: Passive and reactive systems
  • 2004
  • Ingår i: Chemical Engineering Research and Design. - : Elsevier BV. - 0263-8762 .- 1744-3563. ; 82:A2, s. 274-283
  • Tidskriftsartikel (refereegranskat)abstract
    • Mixing of two liquids in a new multifunctional channel reactor developed by AlfaLaval has been studied both experimentally and through computational fluid dynamics (CFD). As the channels are quite narrow the Reynolds numbers are low and the bulk of the channel is within the turbulent boundary layer. This makes accurate a priori predictions of the flowfield difficult and experimental validation necessary. Particle image velocimetry (PIV) was used to measure the flowfield, whereas planar laser-induced fluorescence was used for a scalar concentration field. CFD simulations were performed with the commercial software Fluent 5.5. Different turbulence models were tested and compared with PIV. The best predictions were obtained with a low Reynolds boundary layer k-ε turbulence model. Mixing of a passive tracer, including mean concentration and concentration variance, was calculated with the turbulent mixer model of Baldyga. A reactive system with diazo coupling between 1-naphthols, 2-naphthols and diazotized sulphanilic acid was studied both experimentally and theoretically due to its sensitivity to mixing conditions. The interpolation model of Baldyga was used to predict the evolution of the species. Good agreement was found between simulations and experiments for both the flow field and the reactive system.
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8.
  • Darkins, Christopher Luke, et al. (författare)
  • Design of large-scale manufacturing of induced pluripotent stem cell derived cardiomyocytes
  • 2014
  • Ingår i: Chemical engineering research & design. - : Elsevier. - 0263-8762 .- 1744-3563. ; 92:6, s. 1142-1152
  • Tidskriftsartikel (refereegranskat)abstract
    • A new approach for design of large-scale manufacture of stem cell derived cells by using the biomechatronic methodology and computer-aided-design tools is described. The systematic conceptual design methodology for systems composed of active mechanical, electronic and biological components, here referred to as biomechatronics, is combined with the methodology for computer-aided design of bioprocesses. The objective has been to systematically investigate and compare by the combination of the methodologies what are favourable design alternatives in terms of equipment configuration and economic parameters. A demonstration case has been used for the manufacture of cardiomyocytes from human induced pluripotent stem cells. The results show how certain configurations are more favourable than others under given boundary conditions. The study indicates that the approach is possible to apply on other related bio-manufacturing systems.
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9.
  • Eng, Matthias, 1983, et al. (författare)
  • Influence of solids on macro-instabilities in a stirred tank
  • 2012
  • Ingår i: Chemical Engineering Research and Design. - : Elsevier BV. - 0263-8762 .- 1744-3563. ; 90:8, s. 1052-1062
  • Tidskriftsartikel (refereegranskat)abstract
    • Measurements were conducted in a cylindrical tank stirred with a PBT in order to study the effect of varying amounts of suspended solids, up to 11.8% by volume, on the frequency and amplitude of macro-instabilities (MI). Solid glass particles of three different sizes were used in order to investigate the influence of the particle Stokes number. Measurements were made at 18 different locations in the vessel using laser Doppler anemometry (LDA) and were evaluated with the Lomb algorithm to obtain the frequency spectrum of the liquid flow. The results showed that the MI frequency is not influenced by the addition of solids. However, the MI amplitude was reduced by the addition of the solid phase although still detectable up to the highest concentration measured (11.8 vol.%). In the studied system there seems to be a difference dependent on the particle Stokes number.
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10.
  • Gamero, Rafael, et al. (författare)
  • The use of drying experiments in the study of the effective thermal conductivity in a solid containing a multicomponent liquid mixture
  • 2012
  • Ingår i: Chemical engineering research & design. - : Elsevier BV. - 0263-8762 .- 1744-3563. ; 90:11, s. 1765-1778
  • Tidskriftsartikel (refereegranskat)abstract
    • The effective thermal conductivity of a porous solid containing multicomponent liquid mixtures has been studied. To achieve this, the liquid composition, liquid content and temperature distributions have been measured in a cylindrical sample dried by convection from the open upper side and heated by contact with a hot source at the bottom side. A quasi-steady state reached at high source temperatures permits to calculate the total heat flux from temperatures measured on the surface and the gas stream. The simulations performed and compared with experimental data made it possible to estimate the adjusting geometric parameter of Krischer's model for the effective thermal conductivity. The effective thermal conductivity has been widely studied for two-phase systems, mostly with regard to thermal insulation elements. The calculation of this transport parameter includes the contribution to heat transfer of the evaporation–diffusion–condensation mechanism undergone by the multicomponent mixture. The influence of liquid composition and temperature on the thermal conductivity due to the evaporation–diffusion–condensation mechanism and the effective thermal conductivity is described. The results reveal that in this case the resistance to heat transfer seems to correspond to a parallel arrangement between the phases.
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11.
  • Heckötter, Ulrich, et al. (författare)
  • Effect of annealing time and addition of lactose on release of a model substance from Eudragit® RS coated pellets produced by a fluidized bed coater
  • 2011
  • Ingår i: Chemical Engineering Research and Design. - : Elsevier BV. - 0263-8762 .- 1744-3563. ; 89:6A, s. 697-705
  • Tidskriftsartikel (refereegranskat)abstract
    • The aim of this study was to investigate the effects of annealing time and addition of lactose in coating liquid formulations on the release of a model substance, methylene blue (MB), from pellets coated with Eudragit (R) RS 30 D. The microcrystalline cellulose pellets were layered with MB before coating with aqueous dispersions of Eudragit (R) RS 30 D using a Wurster-type fluidized bed coater. The coating processes and conditions were validated and optimized before the final coating. The uncoated and coated pellets were characterized for their size, MB content, morphology and MB release. The results demonstrated that a stable coating process can be developed to produce repeatable batches of pellets. The film thickness was calculated and found to be similar to those observed from scanning electron microscope. The increased annealing time led to a more coherent film. The drug release was found to vary depending on the duration of annealing time and the addition of lactose. Addition of lactose gave a faster MB release and without any initial lag period in the release profile whereas the increased annealing time slowed down the MB release and increased the lag period.
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12.
  • Hermansson, Sven, 1978, et al. (författare)
  • On-line monitoring of fuel moisture-content in biomass-fired furnaces by measuring relative humidity of the flue gases
  • 2011
  • Ingår i: Chemical Engineering Research and Design. - : Elsevier BV. - 0263-8762 .- 1744-3563. ; 89:11, s. 2470-2476
  • Tidskriftsartikel (refereegranskat)abstract
    • Combustion of biomass for heat and power production is continuously growing in importance, because of incentivesfor replacing fossil energy resources with renewable ones. In biomass combustion, the moisture content of the fuel isan essential operation parameter, which often fluctuates for biomass fuels. Variation in moisture content complicatesthe operation of the furnaces and results in an uncertainty in the energy content of the fuel delivered to a plant.The fuel moisture-content in a furnace may be determined either by direct measurement on the entering fuel or bymeasuring the moisture and oxygen contents of the flue gases deriving the moisture content of the fuel. However,reliable methods of a motivated cost for the small to medium-scale furnaces are today not available. An exception isif the furnace is equipped with flue-gas condenser, which can be used to estimate the moisture content of the fluegases. A limitation of this method is, though, that not all furnaces have flue-gas condensers and that the measuredsignal has an inherent time delay.In thiswork, measurement of the relative humidity (RH) of the flue gases froma furnace is investigated as the centralcomponent in the on-line monitoring of the moisture content of the fuel in a furnace. The method was analysedwith humid air in a laboratory environment and tested for accuracy and dynamical behaviour in two biomass-firedheat-production units, one circulating fluidised-bed boiler (CFB) and one grate furnace. The results show that themethod, which is easy to calibrate on site, can be used to predict the moisture content of the biomass fuel in thegrate furnace with very good precision (
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13.
  • Ho, Hoang Phuoc, 1983, et al. (författare)
  • Facile coating of Co3O4 on open-cell metallic foam for N2O catalytic decomposition
  • 2022
  • Ingår i: Chemical Engineering Research and Design. - : Elsevier BV. - 0263-8762 .- 1744-3563. ; 188, s. 166-178
  • Tidskriftsartikel (refereegranskat)abstract
    • Co3O4 coated on open-cell metallic foams, which can merge the catalytic activity of Co3O4 and advantages derived from the geometry of the support, are promising for environ-mental applications such as the decomposition of N2O (deN(2)O). This study demonstrates how it is possible to easily and reproducibly prepare a well-adhered layer of Co3O4 with a similar specific surface area as the materials prepared with the precipitation method (similar to 23 m(2) g(-1) c(oating)) and controlled thickness on FeCrAlloy open-cell foams of different porosity and dimension by the electrosynthesis of Co(OH)(2) followed by thermal treatment (600 degrees C). The obtained structured catalysts show stable performance after three cycles of catalytic decomposition of N2O between 250 and 550 degrees C, with a similar T-50 of approximately 460 degrees C, which is comparable to the combustion or precipitated catalysts but pro-vides a lower pressure drop. Under the operating conditions with a sequential test, the presence of NO and/or O-2 in the feed gas inhibits partially the catalytic activity of the structured catalysts while the presence of H2O shows a slight enhancement in the N2O conversion at a temperature above 450 degrees C.(c) 2022 Institution of Chemical Engineers. Published by Elsevier Ltd. All rights reserved.
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14.
  • Jareteg, Adam, 1989, et al. (författare)
  • On the roles of interstitial liquid and particle shape in modulating microstructural effects in packed-bed adsorbers
  • 2022
  • Ingår i: Chemical Engineering Research and Design. - : Elsevier BV. - 0263-8762 .- 1744-3563. ; 177, s. 682-693
  • Tidskriftsartikel (refereegranskat)abstract
    • Several industrial applications use packed-bed reactors for heterogeneous processes with intermittent presence of interstitial liquid. One such example is steam-regenerated adsorption systems. Here, we computationally generate two randomly packed beds of the same voidage – one with spheres and one with cylinders – to study the role of particle shape in such a process. We analyze the geometrical characteristics and determine the flow, transport and reaction properties at the same driving pressure difference. We also establish the effect of liquid on these characteristics. The bed of spheres exhibits 69% higher permeability due to differences in microstructure, and its shorter retention time and lower specific surface yields lower conversion in a first-order heterogeneous reaction. However, at the same flow rate, the spheres could be expected to outperform the cylinders. The bed of cylinders exhibits more pronounced local concentration variations due to a dominance of smaller pores, which are not as readily accessible to the flow. The presence of interstitial liquid reduces the permeability and significantly changes the streamwise velocity distributions inside both beds, effectively homogenizing the geometries by filling up the smaller pores. The implications of the present findings for reduced-order modelling of packed-bed adsorbers are discussed.
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15.
  • Jerndal, Erik, 1980, et al. (författare)
  • Thermal analysis of chemical-looping combustion
  • 2006
  • Ingår i: Chemical Engineering Research and Design. - : Elsevier BV. - 0263-8762 .- 1744-3563. ; 84:A9, s. 795-806
  • Tidskriftsartikel (refereegranskat)abstract
    • In chemical-looping combustion, a gaseous fuel is burnt with inherent separation of the greenhouse gas CO2. Oxygen is transferred from the combustion air to the fuel by an oxygen carrier, which is usually a metal oxide, and therefore direct contact between the fuel and the combustion air is avoided. Thus, the products of combustion, i.e., CO2 and H2O, are not mixed with the rest of the flue gases and after condensation almost pure CO2 is obtained, without any energy lost for the separation. A thermal analysis of the process using a large number of possible oxygen carriers was performed by simulating reactions using the HSC Chemistry 5.0 software. Three fuels were used in the investigation, CH4, CO and H2. Based on the ability of the oxygen carriers to convert the fuel to the combustion products CO2 and H2O, stability in air and the melting temperatures of the solid material some metal oxides based on Ni, Cu, Fe, Mn, Co, W and sulphates of Ba and Sr showed good ther-modynamic properties and could be feasible oxygen carriers. Only a few of these possible oxygen carrier systems, based on Cu, Fe and Mn, showed complete conversion of the fuel gas, but still the other systems had limited equilibrium restrictions, with only small and acceptable amounts of unreacted CO and H2 released from the fuel reactor. The promising systems were investigated further with respect to temperature changes in the fuel reactor as well as possible carbon, sulphide and sulphate formation in the fuel reactor. For some systems the reactions in the fuel reactor were endothermic, resulting in a temperature drop in the fuel reactor. However, this drop can be limited by applying a sufficient circulation of particles from the air reactor to the fuel reactor. When Ni or Co is used as oxygen carrier the fuel may need to be desulphurized prior to combustion to avoid formation of solid or liquid sulphides or sulphates. On the other hand, to prevent decomposition of the sulphates BaSO4 and SrSO4, in the fuel reactor, to sulphur-containing gases and metal oxides, it is necessary that some sulphur is present in the fuel and that high temperatures are avoided. Formation of carbon should not be a problem as long as the process is run under conditions of high fuel conversion.
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16.
  • Jiao, Yingqi, et al. (författare)
  • Integration optimization of production and transportation of refined oil : A case study from China
  • 2022
  • Ingår i: Chemical engineering research & design. - : Institution of Chemical Engineers. - 0263-8762 .- 1744-3563. ; 188, s. 39-49
  • Tidskriftsartikel (refereegranskat)abstract
    • The logistics management of refined oil under a separation of production and transportation leads to high logistics costs and a mismatch between the supply and demand sides. This paper intends to develop a general framework to assess the impact of the integration of the production and transportation in terms of economic, environmental, and energy benefits. Firstly, this paper proposes a tactical-level mathematical model for optimizing the integration of production and transportation of refined oil to minimize the total cost. In the model, several factors, such as level of market demand, production capacity limits, transportation modes, and transportation capacity, are taken into consideration. Then, the energy, economy, and environment analysis method are applied to assess the impact of the integration on the field of refined oil logistics. Four scenarios are set up and a comparative analysis is carried out in detail in China. The optimal resource allocation scheme and production adjustment scheme for each scenario are obtained. The results show that after the integration, the logistics cost is reduced by 6.8 %− 11 %, the greenhouse gas emission is reduced by 7.3 %− 17.7 %, and the energy consumption per unit turnover is reduced by 4.4 %− 7.4 %. This proves that the integration of production and transportation guided by the proposed method performs positive economic, environmental, and energy benefits. Finally, policy implications are provided.
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17.
  • Keller, Martin, 1985, et al. (författare)
  • Interaction of mineral matter of coal with oxygen carriers in chemical-looping combustion (CLC)
  • 2014
  • Ingår i: Chemical Engineering Research and Design. - : Elsevier BV. - 0263-8762 .- 1744-3563. ; 92:9, s. 1753-1770
  • Tidskriftsartikel (refereegranskat)abstract
    • The chemical-looping combustion (CLC) and chemical-looping with oxygen uncoupling (CLOU) processes are novel solutions for efficient combustion with direct separation of carbon dioxide. These processes use a metal oxide as an oxygen carrier to transfer oxygen from an air to a fuel reactor, where the fuel reacts with the solid oxygen carrier. When utilizing coal in CLC, the oxygen carrier particles could be affected through interaction with the ash-forming mineral matter found in coal, causing deactivation and/or agglomeration. In this work, possible interactions between minerals commonly encountered in coal and several promising oxygen carriers that are currently under investigation for their use in CLC are studied by both experiment and thermodynamic equilibrium calculations. Possible interaction was studied for both highly reducing and oxidizing conditions at 900 °C. Under highly reducing conditions pyrite was found to have by far the most deteriorating effect on the oxygen carrier particles, as the sulfur in the pyrite reacted with the oxygen carrier to form sulfides. Quartz and clay minerals were found to have a rather low influence on the oxygen carriers. Out of the oxygen carriers investigated, CuO/MgAl2O4 and the Mn3O4/ZrO2 oxygen carriers tended to be quite reactive towards mineral matter whereas ilmenite has been shown to be the most robust oxygen carrier. Although sulfur can clearly deactivate Ni, Cu and Mn based oxygen carriers under sub-stoichiometric conditions, when the fuel is converted fully to CO2 and H2O, sulfides are only expected for Ni-based oxygen carriers.
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18.
  • Larsson, Sylvia, et al. (författare)
  • Deformation and breakage of biofuel wood pellets
  • 2020
  • Ingår i: Chemical Engineering Research and Design. - : Elsevier BV. - 0263-8762 .- 1744-3563. ; 153, s. 419-426
  • Tidskriftsartikel (refereegranskat)abstract
    • A convenient approach to employ an elliptic load-deformation elastoplastic approximation has been proposed and used to evaluate the mechanical behavior of pinewood biofuel pellets from lab-scale compressive load-deformation measurements. Verification of model predictions has been attempted against apparent finite element method based simulations. A database of essential mechanical properties has been established. This submission is intended as a model for being able to study the deformation and breakage behavior using lab-scale compression tests. (C) 2019 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.
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19.
  • Le, Q.K., et al. (författare)
  • Dividing wall columns for heterogeneous azeotropic distillation
  • 2015
  • Ingår i: Chemical Engineering Research and Design. - : Elsevier BV. - 0263-8762 .- 1744-3563. ; 99, s. 111-119
  • Tidskriftsartikel (refereegranskat)abstract
    • The aim of this work is to implement heterogeneous azeotropic distillation schemes in a dividing wall column (DWC) for a feed mixture of water (W), acetic acid (HAC) and an organic component (X). The original design makes use of X to act as an entrainer to facilitate the separation of water and HAC, and we also propose a DWC design based on this idea. This DWC design reduces the capital cost, but the energy usage is almost unchanged. To achieve energy savings and further reductions in capital costs, we need to use a Petlyuk DWC. We introduce isobutyl acetate (IBA) as an additional entrainer for the Petlyuk DWC, and achieve energy savings of about 20%.
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20.
  • Leion, Henrik, 1976, et al. (författare)
  • Solid fuels in chemical-looping combustion using a NiO-based oxygen carrier
  • 2009
  • Ingår i: Chemical Engineering Research and Design. - : Elsevier BV. - 0263-8762 .- 1744-3563. ; 87:11, s. 1543-1550
  • Tidskriftsartikel (refereegranskat)abstract
    • The feasibility of using three different solid fuels in chemical-looping combustion (CLC) has been investigated using NiO as oxygen carrier. A laboratory fluidized-bed reactor system for solid fuel was used, simulating a chemical-looping combustion system by exposing the sample to alternating reducing and oxidizing conditions. In each reducing phase 0.2 g of fuel was added to the reactor containing 20 g oxygen carrier. The experiments were performed at 970°C. Compared to previously published results with other oxygen carriers the reactivity of the used Ni-particles was considerably lower for the high-sulphur fuel and higher for the low-sulphur fuel. Much more unconverted CO was released and the fuel conversion was much slower for high-sulphur fuel such as petroleum coke, suggesting that the nickel-based oxygen carrier was deactivated by the presence of sulphur. The NiO particles also showed good reactivity with methane and a syngas mixture of 50% H2 and 50% CO. For all experiments the oxygen carrier showed good fluidizing properties without any signs of agglomeration.
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21.
  • Leion, Henrik, 1976, et al. (författare)
  • The use of ilmenite as an oxygen carrier in chemical-looping combustion
  • 2008
  • Ingår i: Chemical Engineering Research and Design. - 0263-8762 .- 1744-3563. ; 86, s. 1017-1026
  • Tidskriftsartikel (refereegranskat)abstract
    • The feasibility of using ilmenite as oxygen carrier in chemical-looping combustion has been investigated. Itwas found that ilmenite is an attractive and inexpensive oxygen carrier for chemical-looping combustion.Alaboratory fluidizedbed reactor system, simulating chemical-looping combustion by exposing the sample to alternating reducing and oxidizing conditions,was used to investigate the reactivity. During the reducing phase, 15 g of ilmenite with a particlesize of 125–180μm was exposed to a flow of 450mLn/min of either methane or syngas (50% CO, 50% H2) and during the oxidizing phase to a flow of 1000mLn/min of 5% O2 in nitrogen. The ilmenite particles showed no decrease in reactivity in the laboratory experiments after 37 cycles of oxidation and reduction. Equilibrium calculations indicate that the reduced ilmenite is in the form FeTiO3 and the oxidized carrier is in the form Fe2TiO5 +TiO2. The theoretical oxygen transfer capacity between these oxidation states is 5%. The same oxygen transfer capacity was obtained in the laboratory experiments with syngas. Equilibrium calculations indicate that ilmenite should be able to give high conversion of the gases with the equilibrium ratios CO/(CO2 + CO) and H2/(H2O+H2) of 0.0006 and 0.0004, respectively. Laboratory experiments suggest a similar ratio for CO. The equilibrium calculations give a reaction enthalpy of the overall oxidation that is 11% higher than for the oxidation of methane per kmol of oxygen. Thus, the reduction fromFe2TiO5 +TiO2 to FeTiO3 with methane is endothermic, but less endothermic compared to NiO/Ni and Fe2O3/Fe3O4, and almost similar to Mn3O4/MnO.
  •  
22.
  • Linderholm, Carl Johan, 1976, et al. (författare)
  • Investigation of NiO-based mixed oxides in a 300-W chemical-looping combustor
  • 2010
  • Ingår i: Chemical Engineering Research and Design. - : Elsevier BV. - 0263-8762 .- 1744-3563. ; 88:5-6A, s. 661-672
  • Tidskriftsartikel (refereegranskat)abstract
    • Chemical-looping combustion, CLC, is a novel combustion concept with inherent separation of CO2. This study evaluates the performance of spray-dried nickel-based oxygen carrier particles prepared from commercially available materials. The possibility to optimize the methane conversion while retaining the oxygen transport capacity by mixing different NiO-based oxygen carriers was evaluated and results showed that such optimization was indeed possible. Experiments were carried out in a batch reactor as well as in a continuous 300-W unit. Experiments in the batch reactor evaluated the performance of two different spray-dried particles, individually and mixed, at two different temperatures, 850°C and 950°C. The reference particle, referred to as N-VITO in this study, contained only NiO and NiAl2O4 while the other spray-dried particle was similar to the reference but contained a small amount of MgO as additive in the starting material. It was found that the reference particle had good oxygen-transport characteristics, but that methane conversion left room for improvement. The particle with MgO addition, on the other hand, showed excellent methane conversion, but poor oxygen transport capability, especially at the lower temperature. The 50/50mass-mixture of the two particles resulted in a potent oxygen-carrier batch with the desired qualities. Three experimental series were conducted in the 300-W CLC-unit; (i) using only the reference particle, (ii) using a mixture of the reference particle and the particle with MgO-addition, and (iii) using the previous mixed oxide system together with a small quantity of a high-surface impregnated oxygen-carrier based on NiO and Al2O3. It is shown that the methane conversion to CO2 is dependent primarily on the solids flux in the reactor system, but also on the temperature in the fuel reactor. Results showed that the operation was more stable and that it was possible to obtain better fuel conversion when the mixtures of two or three different oxygen carrier particles were used. With these mixtures, the methane fraction could be brought down to
  •  
23.
  • Malafronte, Loredana, 1986, et al. (författare)
  • Prediction of regions of coalescence and agglomeration along a spray dryer-Application to skim milk powder
  • 2015
  • Ingår i: Chemical Engineering Research and Design. - : Elsevier BV. - 0263-8762 .- 1744-3563. ; 104, s. 703-712
  • Tidskriftsartikel (refereegranskat)abstract
    • Spray drying is a well-established method used in the food industry for production of powders, such as dry milk, coffee, tea, and soup. The operating conditions of spray dryers depend on the product and chamber design. Thus scaling up the process is complex, and simulation tools are needed to reduce time and cost, and to enhance quality of the final product. In this study a validated distributed-parameter model for predicting drying of single particles was combined with a CFD simulation model of an eight-meter pilot dryer to investigate drying kinetics of skim milk powders. A qualitative assessment of the effect of water diffusivity values on preconditions for agglomeration and a multi-scale analysis of coalescence and agglomeration regions were performed. Results showed that accurate water diffusivity values and sticky conditions have to be implemented when modelling spray drying to investigate preconditions for coalescence and agglomeration. The results also showed the need to simulate surface conditions of particles during spray drying to predict probable regions of coalescence and agglomeration. In conclusion, the applied methodology allows understanding of the stickiness ability of a product and size of the chamber. The methodology can be used to support preliminary design of spray dryers.
  •  
24.
  • Mattsson, Tuve, 1979, et al. (författare)
  • Local solidosity of microcrystalline cellulose during dead-end filtration and sedimentation
  • 2013
  • Ingår i: Chemical engineering research & design. - : Elsevier. - 0263-8762 .- 1744-3563. ; 91:6, s. 1155-1162
  • Tidskriftsartikel (refereegranskat)abstract
    • Solid-liquid separation by filtration and sedimentation are important operations used in a wide range of industries. One important characteristic of both the filtration and sedimentation processes is the solidosity of the filter cake/sediment that is formed, affecting the efficiency and design of the separation. In this study local solidosity was investigated using a gamma-attenuation method during both filtration and sedimentation experiments for microcrystalline cellulose, a highly crystalline cellulose with particles of about 2-80 mu m in diameter. Constitutive relationships for the solidosity were investigated using both filtration (i.e. cake build-up and expression) and sedimentation data for experiments at different pH and suspension concentrations. The sedimentation behaviour under these different conditions was also investigated. It was found that a three parameter empirical model could be used to describe the constitutive relationship between local solidosity and local solid compressible pressure for the sediment formed and the filter cake after both cake build-up and expression. This correlation worked well for the material investigated even at low solid compressible pressures.
  •  
25.
  • Menya, E., et al. (författare)
  • Production and performance of activated carbon from rice husks for removal of natural organic matter from water : A review
  • 2018
  • Ingår i: Chemical engineering research & design. - : Institution of Chemical Engineers. - 0263-8762 .- 1744-3563. ; 129, s. 271-296
  • Forskningsöversikt (refereegranskat)abstract
    • Adsorption by activated carbon has great potential to improve natural organic matter (NOM) removal from water. However, the high production and regeneration costs limit its wide scale application. To address these limitations, research efforts have been focused on finding low cost materials that can be transformed into activated carbon. Rice husk is one of such materials of research focus, especially in the developing countries, where over 96% of rice husks are generated globally. Although numerous investigations have been made concerning the production of activated carbon from rice husks, the existing scientific information still remains widely scattered in literature. Furthermore, the scientific information regarding performance of rice husk activated carbon during NOM removal from water still remains poorly documented. This review article therefore provides ample information on efforts made by various researchers concerning production of activated carbon from rice husks and its adsorption performance in relation to NOM removal from water. Properties and pretreatment of rice husks in relation to production of activated carbon are discussed. Activation of rice husks by physical and chemical methods under numerous conditions is reviewed. Factors affecting NOM adsorption by activated carbon are briefly discussed. Adsorption performance of rice husk activated carbon is also reviewed with respect to NOM removal from water, and where possible compared with other source derived activated carbons. The data from literature revealed that NOM removal by rice husk activated carbon can be as effective as commercial activated carbon. Consequently, rice husk activated carbon has potential to serve as an alternative to commercial activated carbon.
  •  
26.
  • Misiulia, Dzmitry, et al. (författare)
  • Effects of the inlet angle on the flow pattern and pressure drop of a cyclone with helical-roof inlet
  • 2015
  • Ingår i: Chemical engineering research & design. - : Elsevier BV. - 0263-8762 .- 1744-3563. ; 102, s. 307-321
  • Tidskriftsartikel (refereegranskat)abstract
    • The effects of inlet angle on the flow pattern and pressure drop in cyclones have been numerically investigated using Large Eddy Simulations with the dynamic Smagorinsky-Lilly subgrid-scale. Five cyclones with helical-roof inlets of different inlet angles and five cyclones with tangential inlets of different inlet heights at the same other geometric dimensions are considered. The results show that, increasing the inlet angle as well as the inlet height (inlet area) decreases the absolute values of positive (close to the cyclone wall) and negative (in the central region) static pressure and tangential velocity in the cyclone body that will probably reduce the collection efficiency. Also, increasing the inlet angle reduces the gas flow rates along the cyclone axis in both downward (outer) and upward (inner) vortices and increases the maximum radial velocity under the vortex finder that can enhance the number of small particles entrained by the gas flow and transferred from that region into the vortex finder and negatively affect the overall collection efficiency. The cyclone pressure drop is mainly generated by the losses in the cyclone body (under the vortex finder) and in the vortex finder. There is a significant decrease in pressure drop with increase of inlet angle. Based on the simulations an expression for the dimensionless pressure drop normalized by the inlet velocity for the cyclone with helical-roof inlet of different inlet angles is derived. Cyclones with helical-roof inlets have a higher aerodynamic efficiency as compared to cyclones with tangential inlets, and the highest aerodynamic efficiency was reached with an inlet angle of 20°.
  •  
27.
  • Mortensen, Hans Henrik, et al. (författare)
  • Local levels of dissipation rate of turbulent kinetic energy in a rotor–stator mixer with different stator slot widths—An experimental investigation
  • 2018
  • Ingår i: Chemical Engineering Research and Design. - : Elsevier BV. - 0263-8762 .- 1744-3563. ; 130, s. 52-62
  • Tidskriftsartikel (refereegranskat)abstract
    • Rotor–stator mixers (RSMs) are widely used for emulsification and mixing. However, relatively little is known about the relationship between RSM design, hydrodynamics and performance. Previous studies have investigated shaft power draw as a function of design. However, power draw alone is not sufficient to predict efficiency. In order to understand the effect on performance it is important to investigate how the local turbulent stress is influenced by design parameters. This study investigates the effect of stator slot width on the local dissipation rate of turbulent kinetic energy using particle image velocimetry coupled with a sub-resolution modeling approach suggested in previous studies. Results are compared to traditional shaft power draw measurements and a set of emulsification experiments. It is concluded that wider slots, although requiring less total shaft power, provide a higher maximal (time-averaged) dissipation rate of TKE, which explains why they give rise to more efficient drop breakup. Apparently, more of the power input is transformed into pumping for the narrower slots which leaves less energy for turbulent dissipation. The study illustrates the need for supplementing traditional power draw measurements with local flow characterization in order to better understand the relationship between RSM hydrodynamics and dispersion performance.
  •  
28.
  • Mortensen, Hans Henrik, et al. (författare)
  • The effect of stator design on flowrate and velocity fields in a rotor-stator mixer : an experimental investigation
  • 2017
  • Ingår i: Chemical engineering research & design. - 0263-8762 .- 1744-3563. ; 121, s. 245-254
  • Tidskriftsartikel (refereegranskat)abstract
    • Rotor-stator mixers (RSMs) are available in different designs, e.g. with different number of stator slots and slot dimensions. However, the relationship between stator design and the RSM hydrodynamics is not well understood. Consequently, manufacturers still base design and stator screen recommendations on trial-and-error.This study reports experimental measurements of how the flowrate through the stator slots, and velocity profiles in the region of relevance for mixing and breakup, is influenced by the stator slot width, using particle image velocimetry. It is concluded that the flowrate can be described by a design dependent flow number for all investigated geometries and that the flow number decreases with increasing slot width. Moreover, by studying the velocity profiles at different rotor speeds and designs, it is concluded that the velocity profile, its skewness and the proportion of back-flow (fluid re-entering the slot) scales with the flow number of the design. This suggests that the flow number, in addition to rotor speed, is a highly relevant parameter for describing the effect of design on batch RSM hydrodynamics.
  •  
29.
  • Nurdiawati, Anissa, et al. (författare)
  • Microalgae-based coproduction of ammonia and power employing chemical looping process
  • 2019
  • Ingår i: Chemical engineering research & design. - : Elsevier. - 0263-8762 .- 1744-3563. ; 146, s. 311-323
  • Tidskriftsartikel (refereegranskat)abstract
    • Hydrogen (H-2) production and storage technologies are the main challenges in the realization of H-2 utilization in which the goal is to achieve high conversion efficiencies and a high storage density. In this study, microalgae gasification and ammonia (NH3) production are proposed to efficiently convert microalgae to NH3 for efficient H-2 storage. The integrated system comprises drying, gasification, syngas chemical looping (SCL), NH3 synthesis, and power generation. Microalgae are converted to syngas in the gasification module and then introduced into the SCL module to produce high-purity H-2 and a separated carbon dioxide (CO2) stream. SCL is also employed to produce a nitrogen (N-2)-rich stream, which can replace a conventional air separation unit (ASU) system. The three operating parameters that are evaluated in this study include the steam to biomass (S/B) ratio during gasification, reducer operating temperature during chemical looping, and recycle to feed streams ratio. An increase in the S/B ratio has a negative effect on the total energy efficiency because the efficiency decreases owing to the reduced production of H-2 in the oxidizer. To maximize the efficiency of NH3 production, a higher recycle ratio is favorable. The proposed integrated system can obtain high total energy efficiency of up to 64.3%, comprising 63.8% NH3 production efficiency and 0.05% power generation efficiency. 
  •  
30.
  • Perdana, Indra, 1973, et al. (författare)
  • Effect of external mass transport on permeation in a Wicke-Kallenbach cell
  • 2009
  • Ingår i: Chemical Engineering Research and Design. - : Elsevier BV. - 0263-8762 .- 1744-3563. ; 87:10, s. 1438-1447
  • Tidskriftsartikel (refereegranskat)abstract
    • Wicke-Kallenbach (WK) cells are often used for studying separation and component transport in porous material. In order to obtain important transport parameters, mathematical models are frequently developed but they generally consider the fluid phase in the WK compartments to be free of concentration gradients and thus external mass transport resistance is neglected. The present work is a detailed study of how the external transport influences permeation through porous material in a WK cell. External mass transfer effects were demonstrated experimentally and they were further studied from three-dimensional (3-D) model simulations. Film theory was applied to develop an appropriate Sherwood number correlation for the external mass transport coefficient. It was shown that the flow in the compartment and geometrical factors of the WK cell had significant influences on the permeation. It was found that introducing the proposed external mass transport correlation into a simplified one-dimensional (1-D) model was adequate to reproduce results from both the experimental data and the 3-D model.
  •  
31.
  • Persson, Ann-Sofie, et al. (författare)
  • Compression analysis for assessment of pellet plasticity : Identification of reactant pores and comparison between Heckel, Kawakita, and Adams equations
  • 2016
  • Ingår i: Chemical engineering research & design. - : Elsevier BV. - 0263-8762 .- 1744-3563. ; 110, s. 183-191
  • Tidskriftsartikel (refereegranskat)abstract
    • The issue of accurate derivation of a granule yield stress by the traditional procedure using the Heckel equation in addition to the Kawakita and Adams equations has been addressed. The accuracy of the derived parameters was assessed from comparison of single-particle yield pressures from uniaxial compressions. The single-particle yield pressure was nearly four-fold higher for microcrystalline pellets of low (LP) compared to of high (HP) porosity. Heckel profiles were derived using in situ (in-die) and ex situ (out-of-die) global porosities and ex situ voidage porosities derived from mercury porosimetry of pellets and retrieved pellets from tablets. The voidage Heckel profiles enabled a clear distinction between the LP and HP pellets in contrast to the global Heckel profiles. Thus, the voidage was concluded as a better descriptor of the effective porosity of the reactant pore system than the global porosity for calculations of the Heckel numbers. Due to the challenging and tedious work of deriving precise voidage data, derivation of Kawakita b(-1) and Adams parameters remains an interesting approach for assessing granule plasticity. These clearly differentiated between the HP and LP plasticity, thus suggesting that both parameters can be used as a descriptor of pellet plasticity in analytical powder compression analysis.
  •  
32.
  • Poulsen, Mathias, et al. (författare)
  • Development and calibration of a model for packed bed marine scrubbers aboard ocean-going vessels
  • 2023
  • Ingår i: Chemical Engineering Research and Design. - : Elsevier BV. - 0263-8762 .- 1744-3563. ; 191, s. 50-65
  • Tidskriftsartikel (refereegranskat)abstract
    • Scrubbers have gained importance in the maritime sector following recent tightening of the emission legislation regarding sulphur. In this work, a model framework based on an Eulerian-Eulerian multiphase model for a packed bed marine scrubber has been developed. The framework account for both dispersed droplets and a packed bed, where sub-models for interfacial forces and heat- and mass transfer are applied for the respective regions. Additionally, a chemistry model and boundary conditions for the nozzles injecting seawater into the scrubber are also implemented. The model framework is calibrated using data from an ocean-going vessel, where the model predictions were within 3% of the measured pressure loss while the discrepancy in the gas and liquid temperatures were between 0.5% and 3.5%. The sulphur concentration predicted by the model varies between − 24% and 25%. However, the concentrations were within 5 ppm of the measured values for all but a single data set.
  •  
33.
  • Schwebel, Georg, 1983, et al. (författare)
  • Comparison of natural ilmenites as oxygen carriers in chemical-looping combustion and influence of water gas shift reaction on gas composition
  • 2012
  • Ingår i: Chemical Engineering Research and Design. - : Elsevier BV. - 0263-8762 .- 1744-3563. ; 90:9, s. 1351-1360
  • Tidskriftsartikel (refereegranskat)abstract
    • Chemical-looping combustion (CLC) is a promising technology for CO2-capture for storage or reuse as a method to mitigate CO2 emissions from the use of fossil fuels. In a CLC system the oxygen carrier is of great importance. Environmentally sound and low cost materials seem to be preferable especially for CLC of solid fuels. The natural occurring ore ilmenite has already been the target of different studies in order to work out its feasibility as oxygen carrier for different fuels. The initial part of this work is a screening of five commercial available ilmenite minerals as oxygen carrier, crushed and sieved to 125-180 mu m. The screening includes an examination of the sulfur released during the first heat up and the activation of the oxygen carrier, indicated by the fuel conversion using alternating reduction (syngas 50 vol.% CO in H-2) and oxidation conditions (10 vol.% O-2 in N-2). The five first cycles were carried out at 850 degrees C to avoid initial agglomeration whereas the main activation cycles have been performed at 950 degrees C in a tubular quartz reactor under fluidized bed conditions. From these experiments it is concluded that rock ilmenites are preferable as oxygen carriers since they revealed an improved fuel conversion, although offering a higher sulfur content, which is released during the initial heat up. One ilmenite mineral was used to investigate the influence of the catalyzed and non-catalyzed water gas shift reaction (WGS) on the fuel gas conversion at 950 degrees C. It was shown, that the WGS has an influence on the final gas composition. Experiments with only H-2 or CO separately as fuel diluted with N-2 have been performed to eliminate the effect of the WGS. Experiments with syngas and therefore activated WGS allow determining its influence on gas composition. To quantify the reaction progress, the law of mass action for the gas consumption is compared to the equilibrium constant at the corresponding temperature. The results from these experiments agree with the results from catalyzed WGS experiments. Therefore, CaO in the size fraction 180-250 mu m was added to the oxygen carrier since it is a well-known WGS catalyst. As a result the overall conversion of hydrogen and carbon monoxide were improved.
  •  
34.
  • Sedin, Peter, et al. (författare)
  • On the measurement and evaluation of pressure and solidosity in filtration
  • 2003
  • Ingår i: Chemical engineering research & design. - : Elsevier BV. - 0263-8762 .- 1744-3563. ; 81:10, s. 1393-1405
  • Tidskriftsartikel (refereegranskat)abstract
    • New test filtration equipment has been constructed that makes simultaneous measurement of local solid compressive pressure and local solidosity possible. Four materials were used to evaluate the new equipment. In this equipment the solidosity was measured with resolution of 1 mm in height (i.e. in the direction of the liquid flow). The experimental error was estimated to be 0.005-0.04 m3 m-3, depending on the properties of the slurry. Constitutive relationships for solidosity, permeability and specific filtration resistance were estimated and an overall good fit was obtained. Furthermore, it was found that the average specific filtration resistance based on the classical filtration equation could differ by as much as 20% compared to corresponding values based on local measurements.
  •  
35.
  • Simões Dos Reis, Glaydson (författare)
  • Pore volume and surface diffusion model (PVSDM) applied for single and binary dye adsorption systems
  • 2022
  • Ingår i: Chemical Engineering Research and Design. - : Elsevier BV. - 0263-8762 .- 1744-3563. ; 182, s. 645-658
  • Tidskriftsartikel (refereegranskat)abstract
    • The PVSDM model was used for single and binary dye adsorption systems. This model is commonly used for adsorption in single systems, but this is the first time used in a binary mixture of dyes in the literature. To that end, a new adsorbent derived from Bauhinia forficata waste was created and described for eventual use in the treatment of a dye combination (methylene blue and crystal violet). The single and binary isotherms revealed that increasing the temperature decreases the methylene blue adsorption capacity while increasing the crystal violet adsorption capacity. The Langmuir and extended Langmuir models described the single and binary systems, respectively. Maximum adsorption capacities of 229.13 mg g(-1) at 298 K for methylene blue and 324.12 mg g(-1) at 328 K for crystal violet were obtained. The thermodynamic parameters showed that the adsorption process for both dyes is spontaneous, being exothermic for the methylene blue and endothermic for the crystal violet. Similar decay curves for the single and binary systems were observed. The PVSDM was able to describe both single and binary adsorption systems. The external mass transfer and the surface diffusion change according to the initial dye concentration and the system type (single or binary). (C) 2022 Institution of Chemical Engineers. Published by Elsevier Ltd. All rights reserved.
  •  
36.
  • Soltani, Soheil, 1984, et al. (författare)
  • Counter-current spray drying with stream separation: Computational modeling of a noveldryer design
  • 2015
  • Ingår i: Chemical Engineering Research and Design. - : Elsevier BV. - 0263-8762 .- 1744-3563. ; 93, s. 163-173
  • Tidskriftsartikel (refereegranskat)abstract
    • Spray drying has been in use for producing fine powder of pharmaceuticals in order to make the drug respirable and thus accessible to the large absorptive area of the lungs. However, traditional designs for spray dryers have turned out to be inappropriate for processing very fine particles. Therefore, a novel design has been suggested in which the drying agent is separated from the moisture-containing material by using a vapor-permeable membrane (Gerde, 2009). A computational model of the new design has been developed for design and optimization purposes. The model has been shown to satisfactorily reproduce the experimental measurements. A linear correlation has been obtained between the swirl flow rate and the outflow concentrations, predicting a maximum possible flow rate of1 L/min in order to meet the required quality of the product. The performance of the dryer has been shown to be very sensitive to the injection flow rate as well as the effective diffusivity of the membrane. Using ethanol as the solvent,the model predicts a maximum injection of 12 mg/min. Based on the simulation results, a fairly low probability of wall deposition is expected.
  •  
37.
  • Stanicic, Ivana, 1994, et al. (författare)
  • Combined manganese oxides as oxygen carriers for biomass combustion — Ash interactions
  • 2019
  • Ingår i: Chemical Engineering Research and Design. - : Elsevier BV. - 0263-8762 .- 1744-3563. ; 149, s. 104-120
  • Tidskriftsartikel (refereegranskat)abstract
    • © 2019 Institution of Chemical Engineers Carbon capture and storage (CCS) has been acknowledged as an important strategy for mitigation of climate change. Although highly applicable for fossil fuels, CCS with biomass could have the added advantage of resulting in negative emissions of carbon dioxide. One promising carbon capture technology is chemical-looping combustion (CLC). In CLC the reactors are filled with metal oxide bed material called oxygen carriers. Before CLC can be implemented for biomass combustion at a large scale, biomass ash components interaction with oxygen carriers needs to be further understood. Four combined manganese oxides Mn3O4-SiO2, Mn3O4-SiO2-TiO2, Mn3O4-Fe2O3 and Mn3O4-Fe2O3-Al2O3 were exposed to common biomass ash components K, Ca and P. The ash components can exist in many forms, but here the compounds CaCO3, K2CO3 and CaHPO4 were used. Exposures were performed at 900 °C for six hours in oxidising, reducing and inert conditions. Crystalline phases were analysed by XRD and morphology examined with SEM-EDX. Results show that oxygen carrier particles containing silicon were more likely to form agglomerates, especially in combination with potassium, whereas the particles including iron were more stable. MnFeAl was the oxygen carrier that showed least agglomerating behaviour while simultaneously showing a propensity to absorb some ash components. Some inconsistencies between thermodynamic predictions and experimental results is observed. This may be explained by lack of relevant data in the used databases, were only a few of the oxygen carrier-ash systems and subsystems have been optimised. Further optimisation related to manganese rich systems should be performed to obtain reliable results.
  •  
38.
  • Sultana, Nazmun, et al. (författare)
  • Synthesis and kinetic analysis of green AA-type monomers using linoleic acid through bromide promoted transition metal-catalyzed oxidation with air
  • 2023
  • Ingår i: Chemical engineering research & design. - : Elsevier BV. - 0263-8762 .- 1744-3563. ; 190, s. 536-549
  • Tidskriftsartikel (refereegranskat)abstract
    • The present study explores the renewable route to synthesize AA-type monomers for condensation polymerization, namely adipic and azelaic acid, from linoleic acid (LA) using a bromide-promoted transition metal catalyst. For this, liquid-phase catalytic oxidation of LA is carried out using a catalyst system involving the acetates of Cobalt(II) and Manganese(II) and hydrogen bromide in an acetic acid green solvent at temperature: 393-423 K and a pressure of 5.8-8.8 bar in the air. The oxidation products are confirmed by a gas chromatography-mass spectrometer and carbon dioxide analyzer. At the early stage of LA oxidation (i.e., < 5.0 h), the identified major products are malonic acid, azelaic acid, and adipic acid, whereas malonic acid decomposes to carbon dioxide after increasing oxidation time. The influence of process variables, i.e., (i) the loading of LA, bromide, Cobalt(II), and Manganese(II), (ii) temperature, and (iii) pressure on LA conversion and yield of adipic acid and azelaic acid have also been carried out, and the loading of catalyst, pressure, and temperature plays a vital role on the LA conversion and product yields. The temperature-dependent kinetic parameters are also determined, and the rate-controlling step for LA oxidation is analyzed and further extended by evaluating the Hatta number and enhancement factor. The lower values of the Hatta numbers and enhancement fac-tors suggest that the oxidation using air is controlled by the diffusion of oxygen and re-action in the film, and adequate gas-liquid mixing will improve the rate of LA oxidation.
  •  
39.
  • Svensson, Elin, 1980, et al. (författare)
  • The effect of high solids loading in ethanol production integrated with a pulp mill
  • 2016
  • Ingår i: Chemical Engineering Research and Design. - : Elsevier BV. - 0263-8762 .- 1744-3563. ; 111, s. 387-402
  • Tidskriftsartikel (refereegranskat)abstract
    • In this paper, two ethanol processes integrated with a softwood pulp mill are compared with regard to their steam demand, process integration potential and profitability. The processes differ in the solids loading in the simultaneous saccharification and fermentation step and in the resulting ethanol concentration. The results show that a higher ethanol concentration does not necessarily lead to significant reductions in steam demand. Instead, it is demonstrated that the steam demand for distillation is highly dependent on the design of the distillation plant. Nevertheless, a higher solids loading (high gravity) can be beneficial for the treatment of the stillage from the distillation plant. A higher solids loading results either in a lower steam demand for evaporation of the stillage or possibly in a reduced demand for effluent treatment compared to a conventional solids loading process. While the results show that a higher ethanol concentration leads to advantages in energy costs and investment costs for the distillation plant, they also show that the potential benefits of a high-gravity process are offset by the expected decrease in ethanol yield, which leads to higher raw material costs. (C) 2016 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.
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40.
  • Tumsa, Tefera Zelalem, et al. (författare)
  • Concomitant removal of NOx and SOx from a pressurized oxy-fuel combustion process using a direct contact column
  • 2018
  • Ingår i: Chemical Engineering Research and Design. - : Elsevier BV. - 0263-8762 .- 1744-3563. ; 131, s. 626-634
  • Tidskriftsartikel (refereegranskat)abstract
    • The simultaneous removal of NO x and SO x using a direct contact column has potential for efficient treatment of the flue gases arising from pressurized oxy-fuel combustion. This study focuses on a parametric analysis of the efficiency of NO x and SO x removal from the flue gas of an oxy-fuel combustion process using an Aspen Plus direct contact column model. The chemistry implemented in this model reflects the state-of-the-art NO x and SO x reaction mechanisms, with particular emphasis on the liquid-phase chemistry, including pH-dependency. The effects of pressure, water flow rate, and recycle ratio on the removal efficiencies of NO x and SO x were evaluated. The evaluation was conducted based on the base case pressurized (15 bar) flue gas with a feed rate of 120 kg/s and inlet temperature of 40 °C before it was supplied to the column. NO x removal efficiency increased from 70% to 97% when the pressure increased from 15 bar to 30 bar, whereas 99.9% of the SO 2 was absorbed from the flue gas at 15 bar. We show that the removal efficiency is pH-sensitive and it is directly influenced by the recycle ratio and liquid-to-gas ratio (L/G). As the L/G ratio was increased, the removal efficiency of SO x and NO x increased. On the other hand, when the recycle ratio of bottom liquid was increased, the removal efficiency of SO x and NO x decreased.
  •  
41.
  • Uus-Penttila, M. S., et al. (författare)
  • Experimental study for agglomeration behaviour of paracetamol in acetone-toluene-water systems
  • 2003
  • Ingår i: Chemical engineering research & design. - 0263-8762 .- 1744-3563. ; 81:A4, s. 489-495
  • Tidskriftsartikel (refereegranskat)abstract
    • Agglomeration behaviour of paracetamol was studied in acetone-toluene-water systems. The aim was to experimentally determine how the solvent composition influences the agglomeration tendency of paracetamol. It was found that for the chosen solvent system there is one main region where paracetamol agglomerates: the region with large amounts of acetone (>65 wt%) and very small amounts of water (<4 wt%). The same behaviour can be observed both within the one-phase region and within the two-phase region. The experimental agglomeration results were compared with molecular simulations from literature. Both methods indicate that it is more likely for paracetamol crystals to agglomerate in organic systems than in aqueous systems.
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42.
  •  
43.
  • Vendel, M., et al. (författare)
  • Initiation of incrustation by crystal collision
  • 2000
  • Ingår i: Chemical engineering research & design. - : Elsevier BV. - 0263-8762 .- 1744-3563. ; 78:A5, s. 749-755
  • Tidskriftsartikel (refereegranskat)abstract
    • Initiation of incrustation by collision between crystals and a solid surface is investigated. The suspension flow towards the vessel wall in a crystallizer is simulated by laboratory experiments. A liquid jet of supersaturated suspension impinges on a plate at well defined hydrodynamics, supersaturation and parent crystal size. Experiments have been carried out with succinic acid/water. The results indicate that crusts may be initiated at supersaturation well below the metastable limit. Crusts are initiated on both Teflon(TM) and steel. More crust nuclei are formed by collision initiation on sanded stainless steel than on polished stainless steel or Teflon(TM). The results support the hypothesis that collision initiation of crusts is of industrial importance, and suggest that attention should be devoted to the hydrodynamics of crystallizers.
  •  
44.
  • Vikash, Vikash, 1987, et al. (författare)
  • Turbulent statistics of flow fields using large eddy simulations in batch high shear mixers
  • 2019
  • Ingår i: Chemical Engineering Research and Design. - : Elsevier BV. - 0263-8762 .- 1744-3563. ; 147, s. 561-569
  • Tidskriftsartikel (refereegranskat)abstract
    • Large eddy simulations (LES) have been carried out for the first time to characterize the flow and turbulent characteristics in three different batch high shear mixers (HSMs) at a constant rotor speed of 4000 rpm. Three HSMs having different stator heads such as circular, square and inclined stator head with 6, 92 and 210 numbers of stator holes, respectively have been investigated. Dynamic Smagorinsky model with sliding mesh method is used for the sub-grid scale stresses at a Reynolds number of 52,000, to overcome the prediction of RANS models. Numerical methodology is validated, in terms of Power number with the available numerical and experimental studies and found in fairly good agreement. The velocity flow patterns and fluctuations at different planes are predicted and vortexes have been observed within the stator holes and bulk fluid. It is observed that velocity magnitude fluctuation isa function of rotor rotations and stator holes size, and fluctuations in one jets emerging from stator holes affect the fluctuations in other plane jets. Further, it is found that smaller the stator holes size, greater is the energy distribution and hence greater will be the drop size distribution in the mixer. Therefore, the inclined stator head HSM can be used for the uniform size distribution in application to de-agglomeration and dispersion. It is found that the energy spectrum of Kolmogorov is followed over the entire length scale for all HSMs and LES provided the richer flow and turbulent information as compared to RANS model.
  •  
45.
  • Virdung, Torbjörn, 1974, et al. (författare)
  • Measurements using LDV of continuous phase velocities of solid-liquid flow at elevated concentrations in a stirred vessel
  • 2007
  • Ingår i: Chemical Engineering Research and Design. - : Elsevier BV. - 0263-8762 .- 1744-3563. ; 85:A2, s. 193-200
  • Tidskriftsartikel (refereegranskat)abstract
    • Laser Doppler velocimetry was used to evaluate liquid axial velocities and turbulence levels in a stirred vessel equipped with a standard 45° pitch blade turbine. The measurements were conducted utilizing the method of matching refractive indices. Three different solid particle sizes were studied; 1.0 mm, 1.5 mm and 2.0 mm, and the maximum mean volume fractions for which measurements could be performed were 6%, 9% and 9%, respectively. The axial velocities were found to decrease with increasing solid content while the liquid r.m.s. velocities were higher in the suppensions than in a single phase flow, an effect that increases with increasing particle size.
  •  
46.
  • Westerberg, Niklas, 1981, et al. (författare)
  • Chromatographic separation of wood model constituents-Mathematical modeling and parameter estimation
  • 2014
  • Ingår i: Chemical Engineering Research and Design. - : Elsevier BV. - 0263-8762 .- 1744-3563. ; 92:7, s. 1363-1370
  • Tidskriftsartikel (refereegranskat)abstract
    • A mathematical model of the hydrophobic adsorption chromatographic separation of wood model constituents has been developed. Veratryl alcohol was selected to illustrate a lignin molecule and salicin was selected to illustrate a lignin-carbohydrate complex. A variety of available experimental methods in combination with parameter fitting was used to estimate the parameters of packed bed porosity, axial dispersion, film mass transfer, diffusivities and adsorption equilibria with a phenylic silica stationary phase. The model was verified to simulate the separation to within an accuracy of 95%. The model was, however, unable to predict the phenomenon of elution curve fronting, caused by the channeling of the packed bed.
  •  
47.
  • Yamanee-Nolin, Mikael, et al. (författare)
  • Trajectory optimization of an oscillating industrial two-stage evaporator utilizing a Python-Aspen Plus Dynamics toolchain
  • 2020
  • Ingår i: Chemical Engineering Research and Design. - : Elsevier BV. - 0263-8762 .- 1744-3563. ; 155, s. 12-17
  • Tidskriftsartikel (refereegranskat)abstract
    • Evaporators are integral parts of many separation processes across production industries, and they need to be well understood in order to be operated well, thereby enabling high resource-efficiency and productivity. In a previous investigation, the effects of disturbing oscillations in a two-stage evaporator system were quantified. In the current study, these oscillations were reduced through trajectory optimization using steam consumption as a temporally discretized decision variable, taking advantage of a dynamic process flowsheet model in Aspen Plus Dynamics (APD) employed as if it were a black-box model. The optimization was performed utilizing a Python-APD toolchain with the SciPy implementation of COBYLA. The optimal trajectory was able to successfully reduce the objective function value (including the product stream mass flow variance and a bang-bang penalty on the trajectory itself) to slightly less than 0.3 % of that of the nominal case, in which a time-invariant steam consumption was employed. This in turn grants opportunities to increase throughput of the process, leading to significant financial gains.
  •  
48.
  • Yu, Cunming, et al. (författare)
  • Nature–Inspired self–cleaning surfaces: Mechanisms, modelling, and manufacturing
  • 2020
  • Ingår i: Chemical Engineering Research and Design. - : Elsevier BV. - 0263-8762 .- 1744-3563. ; 155, s. 48-65
  • Tidskriftsartikel (refereegranskat)abstract
    • Nature-inspired self-cleaning surfaces have attracted considerable attention from both fundamental research and practical applications. This review adopts a chemical-engineering point of view and focuses on mechanisms, modelling, and manufacturing (M3) of nature-inspired self-cleaning surfaces. We will introduce six nature-inspired self-cleaning mechanisms: The Lotus-effect, superhydrophobic-induced droplet jumping, superhydrophobic-induced unidirectional movement of water droplet, underwater-superoleophobic-based self-cleaning, slippery-based self-cleaning, and dry self-cleaning. These mechanisms of nature self-cleaning examples are popular and well-known as well as have been widely applied or exhibited potential applications in our daily life and industrial productions. The mathematical and numerical modelling of the identified self-cleaning mechanisms will be carefully introduced, which will contribute to the rational design and reproducible construction of these functional self-cleaning surfaces. Finally, we will discuss how these materials can be produced, with a focus on scalable manufacturing. We hope this review will strengthen the understanding on nature-inspired self-cleaning surfaces and stimulate interdisciplinary collaboration of material science, biology and engineering.
  •  
49.
  • Zhou, Jiale, et al. (författare)
  • Effect of spray operation conditions on Nox emission control in a power station
  • 2023
  • Ingår i: Chemical engineering research & design. - : Institution of Chemical Engineers. - 0263-8762 .- 1744-3563. ; 191, s. 214-225
  • Tidskriftsartikel (refereegranskat)abstract
    • Adequately mixing of reactants is an important factor for efficient deNOx process in power station NOx emission control system. In this study, an experimental validated CFD simulation is conducted to investigate the effect of spray operation conditions on the mixing uniformity of reactant ammonia vapor in deNOx process occurring in a power station's furnace. According to the CFD simulation results, it is found that spray momentum ratio, initial droplet size and initial ammonia concentration all affect the mixing uniformity of ammonia vapor. Overall, a larger spray momentum ratio, larger initial droplet size and lower ammonia concentration contributes positively to the mixing uniformity. By comparing the same spray momentum ratio but different nozzle inlet velocity and furnace inlet velocity, it is found that the impact of spray momentum ratio mainly comes from furnace inlet velocity not nozzle inlet velocity. In addition, gravity should not be neglected. In the end, the method described in this study could provide a systematic way to study the effects of nozzle operation conditions on deNOx process.
  •  
50.
  • Zhou, Mi, 1985, et al. (författare)
  • Investigation of the cohesive strength of membrane fouling layers formed during cross-flow microfiltration: The effects of pH adjustment on the properties and fouling characteristics of microcrystalline cellulose
  • 2019
  • Ingår i: Chemical Engineering Research and Design. - : Elsevier BV. - 0263-8762 .- 1744-3563. ; 149, s. 52-64
  • Tidskriftsartikel (refereegranskat)abstract
    • Fluid dynamic gauging was used to investigate the cohesive strength of the membrane fouling layer formed during cross-flow microfiltration of microcrystalline cellulose. Fouling behaviour was compared at two pH levels (i.e. different surface charges of the particles and membranes) with two membranes (i.e. regenerated cellulose and polyethersulphone). It was found that a suspension at low pH, where the surface charge of the particles is close to zero, resulted in thicker and stronger surface fouling layers (668 ± 66 μm thick at a shear stress of 36 Pa for the regenerated cellulose membrane). The permeate flux was reduced by 62% during the first 1000 s. For close-to-neutral pH, where the particles are negatively charged, the fouling layers were thinner and less resistant to shear stress (290 ± 77 μm thick at a shear stress of 36 Pa) and the decline of the flux was faster: a 90% decrease was recorded during the initial 1000 s. The differences in flux decline behaviour suggest a more pronounced blocking of the pore openings for the membranes at the higher pH. Similar fouling behaviour was observed for the two membranes. An atomic force microscope equipped with a colloid probe was used to evaluate particle/particle and particle/membrane interactions.
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