bluuebunny/crossref_metadata_2025_split huggingface dataset:
A new process for toxic metal uptake by a kraft lignin
Authors: Crist DeLanson R , Crist Ray H , Martin J Robert 
Published: February 2003

AbstractA new approach toward removing toxic metals from industrial process water has been investigated using kraft lignin, a by‐product of paper production. A detailed study on a kraft pine lignin powder (Indulin AT from MeadWestvaco), which has acid functions that can act as ion‐exchange sites, has shown that uptake of divalent toxic metals is accompanied by a release of protons or existing metals from the lignin. Equilibrium constants for displacement of protons decreased with pH, and equilibrium constants for metal–metal exchange showed that binding strengths follow the order (highest to lowest): Pb, Cu, Zn, Cd, Ca, Sr. A demonstrated stoichiometry of one mole Ca displaced for one mole of metal (Sr or Cd) sorbed is fully consistent with a chemical reaction of ion exchange and difficult to explain by frequently used adsorption models (Langmuir adsorption isotherm and biotic ligand model). Since the powder after metal uptake is hard to separate from purified water on a large scale, a novel formulation has been investigated for toxic metal removal.© 2003 Society of Chemical Industry
Non‐traditional three‐phase reactor setup for simultaneous acoustic irradiation and hydrogenation
Authors: Mikkola Jyri‐Pekka , Kubicka David , Kuusisto Jyrki , Granholm Nina , Salmi Tapio , Holmbom Bjarne 
Published: February 2003

AbstractA tailor‐made autoclave setup for simultaneous acoustic irradiation and hydrogenation was used in the hydrogenation of fatty acids and carbohydrates. The aim was not to perform actual sonochemistry but to retard deactivation of the catalyst by means of acoustic irradiation. The catalyst used was a Raney nickel one that tends to deactivate quite rapidly from batch to batch. The results indicated that in the case of the aqueous system (xylose hydrogenation to xylitol) the effect is clear. In the case of the fatty acids one actually observed an enhancement of the reaction rate: with recycled catalyst the second and third batch proceeded somewhat faster than the first one.© 2003 Society of Chemical Industry
Gluconic acid production under varying fermentation conditions by Aspergillus niger
Authors: Singh Om V , Jain Rakesh K , Singh Rajesh P 
Published: February 2003

AbstractThe production of gluconic acid with respect to varying substrate concentrations in submerged (SmF), semisolid‐state (SmSF), surface (SF), and solid‐state surface (SSF) fermentations was analyzed. Under the various fermentation conditions the biomass and specific growth rate varied with different concentrations of glucose. The highest level of gluconic acid (106.5 g dm−3) with 94.7% yield was obtained under SSF conditions. In all cases the maximum degree of gluconic acid conversion was observed at on initial substrate concentration of 120 g dm−3. The rate of glucose uptake increased on increasing the initial glucose concentration and glucose utilization was observed to be highest (89–94%) in the SmSF process and was comparable with the SSF and SF processes. The maximum rate of cell growth was obtained in all processes at an initial glucose concentration of 120 g dm−3. The gluconic acid production and change in pH were analyzed at varying time intervals and it was observed that the SmF and SmSF processes were completed within 6 days of incubation whereas the highest yield was observed after 12 days of incubation and continued thereafter in the SSF process.© 2003 Society of Chemical Industry
Adsorption of dioxins and furans from flue gases in an entrained flow or fixed/moving bed reactor
Authors: Everaert Kim , Baeyens Jan , Creemers Claude 
Published: February 2003

AbstractUnder certain operating conditions, polychlorinated dioxins and furans occur in the flue gases of thermal processing plants. Current EU Directives limit the concentration of these emissions to less than 0.1 ng toxicity equivalents (TEQ) per standard cubic metre of dry gas at 11 vol% O2. These Directives have been included in the emission regulations of most of the EU countries. Dioxins and furans are not particular to incinerators; they can also originate from metallurgical and other thermal processes when these are operated under unfavourable conditions. Adsorption methods employing non‐flammable carbonaceous adsorbents (activated carbon, lignite) are particularly well suited for removing PCDD/Fs. For adsorption, which requires the sorbent to be brought in contact with the gas to be cleaned, various processes are currently available, ie classical adsorption in moving/fixed bed filters or the technique of adsorption in an entrained dust cloud with a downstream fabric filter or electrostatic precipitator to remove the spent sorbent from the waste gas (entrained process). The paper will firstly assess both adsorption concepts; it will then use results obtained from operational tests in incineration plants for municipal and industrial waste to describe the efficiency of the dioxin‐sorption in an entrained bed (pneumatic transport of pulverized adsorbent) and a fixed/moving bed (granular adsorbent). Variations in the dosing rate and the use of different adsorbents, as well as the operating temperature, identify the selection criteria for determining the process‐engineering optimum for flue gas cleaning. The paper will demonstrate that the PCDD/F emissions can be reduced to below 0.1 ng TEQ Nm−3 and will identify the operating conditions required to achieve this standard.© 2003 Society of Chemical Industry
A study of velocity and residence time of single bubbles in a gassed oscillatory baffled column: effect of oscillation amplitude
Authors: Oliveira Mónica S N , Fitch Andrew W , Ni Xiong‐Wei 
Published: February 2003

AbstractIn this paper, the experimental evaluation of velocity and residence time of single bubbles of different sizes in a gassed oscillatory baffled column (OBC) using a high‐speed imaging technique is reported. This work is particularly concentrated on the effect of oscillatory amplitude. The results show that the instantaneous axial bubble velocities vary up to four times with respect to the mean value at an oscillatory amplitude greater than 2 mm. The ratio of the radial to axial bubble velocity increases beyond unity for the highest oscillation amplitude investigated. The direct measurement of residence time of the bubbles within a baffled cell is also reported.© 2003 Society of Chemical Industry
A review on combustion synthesis of novel materials: recent experimental and modeling results
Authors: Cincotti Alberto , Licheri Roberta , Locci Antonio Mario , Orrù Roberto , Cao Giacomo 
Published: February 2003

AbstractSolid–solid and gas–solid self‐propagating high temperature reactions are exploited for interesting and relatively new technological applications in the field of combustion synthesis. This paper describes the characteristics of this technique by focusing on the synthesis of some reacting systems recently investigated by Cao and coworkers, such as Ti3Al, TiAl, and ZrO2/SiC. Experimental as well as modeling issues are tackled by pointing out the need of a proper comparison between the corresponding results related to their dynamic behavior, in the framework of a structural dynamics approach. This methodological procedure seems to be able to determine a reliable set of model parameters necessary for successful scaling up and industrial applicability of combustion synthesis‐based technology.© 2003 Society of Chemical Industry
Modelling of mixing in a Taylor‐Couette reactor with axial flow
Authors: Syed Amjad , Früh Wolf‐Gerrit 
Published: February 2003

AbstractTaylor–Couette flow with superimposed axial flow is becoming increasingly accepted as a novel reactor type offering a wide range of mixing regimes within a single reactor vessel, depending on the operating conditions of the reactor. To exploit the potential of such a reactor fully, the mixing processes in the reactor have to be well understood. A variant of an established model to simulate flow in a Taylor–Couette reactor with axial flow is presented. The model, which is based on the description of the flow as a linked network of stirred tanks, attempts to develop a parameterisation of the mass exchange processes between Taylor vortices and the by‐pass stream on a rational basis. Some numerical results are presented and compared with results from the literature.© 2003 Society of Chemical Industry
TNO's work on intensification: practical examples
Authors: Walpot Jan I 
Published: February 2003

AbstractTNO, a Dutch organisation for contract research, is and has been involved in numerous process intensification projects in close collaboration with national and international process industries. TNO has different facilities available to fulfil the demands of intensification projects. Depending on the focus of a project, a multidisciplinary team conducts experimental research, feasibility studies, process modelling, process design, pilot research and/or E‐evaluations (economics, environment, energy). In this conference paper practical cases are described concerning novel processing techniques as well as novel reactors.© 2003 Society of Chemical Industry
Internal heat integration – the key to an energy‐conserving distillation column
Authors: Olujic Z , Fakhri F , de Rijke A , de Graauw J , Jansens P J 
Published: February 2003

AbstractThis paper illustrates the thermal energy conservation potential of the so‐called heat integrated distillation column (HIDiC), which combines advantages of direct vapour recompression and diabatic operation at half of the normal column height. In a typical close boiling mixture separation, compared with a column utilising the usual vapour recompression scheme, HIDiC halved the consumption of exergy at approximately the same capital cost, indicating a strikingly short pay‐off time. The complexities of integrating the heat transfer equipment in the stripping section with proven gas/liquid contacting devices, which may work adversely to practical implementation of HIDiC concept, are also addressed.© 2003 Society of Chemical Industry
Simplified protein purification using engineered self‐cleaving affinity tags
Authors: Wood David W 
Published: February 2003

AbstractThe biological revolution, spurred on by the completion of the human genome project, will increase the demand for inexpensive and reliable methods for protein expression and purification. Over the past 20 years, several technologies have been developed where target proteins or expression systems are manipulated at the genetic level to increase productivity. The use of genetically‐fused affinity tags has been particularly successful, and this technique has become ubiquitous in research. However, the high cost of this approach, along with some regulatory issues, have prevented it from becoming more widely adopted at large scale. Recently, self‐cleaving protein elements have been developed that can effectively make affinity tags self‐cleaving, allowing the release of the product directly from the affinity column under extremely mild conditions. The low cost of this approach, combined with the power of an affinity separation, promise to make this an exciting new purification technology for future research and manufacturing applications.© 2003 Society of Chemical Industry
Enhancement of ultrafiltration using gas sparging: a comparison of different membrane modules
Authors: Cui Zhanfeng , Taha Taha 
Published: February 2003

AbstractUltrafiltration is widely used in the chemical, pharmaceutical, food and water industries. Practical difficulties arise in designing and operating the process due to concentration polarisation and membrane fouling. Enhancement of ultrafiltration is highly desirable to achieve a higher permeate flux at a fixed energy input, or a reduced energy input whilst maintaining the level of permeate flux, or an improved selectivity of the membrane. One effective, simple, and economic technique used to enhance ultrafiltration is the use of gas bubbles, ie injecting gas into the feed stream to create a gas–liquid two‐phase cross‐flow operation. In this paper, an attempt is made to compare the effect of ‘bubbling’ on the ultrafiltration performance, using different membrane modules (in particular, tubular and hollow fibre membrane modules). The difference in performance can be related to the feature of two‐phase flow hydrodynamics and its respective effect on mass transfer. The advantages and drawbacks of using this technique to enhance ultrafiltration are discussed.© 2003 Society of Chemical Industry
Using process intensification in the actinide processing industry
Authors: Yarbro Stephen L , Schreiber Stephen B 
Published: February 2003

AbstractAll industrially significant actinides have hazards associated with their storage and handling. All are radioactive and potentially fissile which limits the amount of material that can be processed in a given unit operation to prevent a criticality accident. To protect workers from the radiation and direct exposure to these toxic elements, processing is done in remote‐handling facilities or within engineered barriers like glove boxes. Such facilities are expensive to build, operate, and maintain. Actinides also have high waste handling, storage and disposal costs due to their radioactivity and toxicity. These processing constraints make actinide processing an excellent candidate for process intensification as they are separated from undesirable fission products or purified to usable product. Using specially designed equipment that enhances the mixing and mass transfer or combining several unit operations in single unit are typical of process intensification. Annular centrifugal contactors are an excellent example of applying Taylor–Couette type flow to mix two immiscible fluids and then separating them centrifugally. Hence, two operations are combined in one unit.© 2003 Society of Chemical Industry
Production of pullulan using an oscillatory baffled bioreactor
Authors: Gaidhani Hemraj K , McNeil B , Ni Xiong‐Wei 
Published: February 2003

AbstractPullulan is a well‐known extracellular polysaccharide produced by the aerobically growing yeast‐like fungus Aureobasidium pullulans (A pullulans). Pullulan has a wide range of commercial and industrial applications, eg it is used in adhesives, in laminates or nylon‐like fibres and fabrics, and in various foods as a low calorie ingredient. Pullulan itself is produced and deposited on the outside of the fungal cells, and because of the low oxygen permeability of the pullulan, this layer acts as a barrier for the transfer of oxygen from the medium to the fungus. This could be detrimental to the survival of the cells and, in turn, restrict the cultivation of the pullulan. In pullulan fermentation it is therefore desirable to break up and remove this layer of pullulan adherent to the cells. The conventional impeller‐driven vessels often exhibit a gradient in mixing capabilities, with high intensities at and near the impeller but low intensities in peripheral regions. Such gradients increase significantly with the scale. The existence of the mixing gradient in a given vessel can potentially inhibit the process of pullulan generation in regions distant from the impeller, leading to reduced productivity. The oscillatory baffled bioreactor (OBB) offers enhanced and uniform mixing at very low shear rate compared with conventional mixing vessels; this would provide better control over the cultivation of pullulan. In this paper, the production of pullulan in the OBB is reported and compared with the fermentation process carried out in a conventional stirred tank fermenter.© 2003 Society of Chemical Industry
Development of nickel‐activated catalytic filters for tar removal in H2S‐containing biomass gasification gas
Authors: Zhang Yuhong , Draelants Dirk J , Engelen Karen , Baron Gino V 
Published: February 2003

AbstractThe urea method was applied to deposit a nickel–calcium catalyst inside porous filter discs to develop a gas cleaning technique involving the combined removal of tars and particles from hot biomass gasification gas. Some catalytic filter discs were tested in typical filtration conditions for the decomposition of the model tar compound benzene in a simulated biomass gasification gas containing representative amounts of H2S. H2S‐deactivation studies showed a significant improvement in the sulfur resistance of the nickel catalyst on the filter discs by the addition of CaO to the catalyst formulation. The optimisation of the ratio between Ni and CaO and the effect of nickel content in the catalyst formulation on the catalytic performance were investigated.© 2003 Society of Chemical Industry
Increasing gas–liquid contacting using a confined plunging liquid jet
Authors: Atkinson B W , Jameson G J , Nguyen A V , Evans G M 
Published: February 2003

AbstractThe plunging liquid jet bubble column is an effective device for gas–liquid contacting. Small bubbles are formed in a high‐shear region surrounding the plunging jet, leading to high interfacial area per unit volume of gas. At the same time, the counter‐current flow downstream of the jet leads to regions of high gas holdup, producing high interfacial area per unit volume of reactor. This paper presents a study of the void fraction in the pipe‐flow zone of the downcomer in a plunging jet reactor. It was found that the Ergun equation, using the standard constants derived from data for pressure drop in packed beds of solids, successfully predicted the gas void fraction for both bubbly and churn‐turbulent flow conditions provided the increase in bubble size, with increasing gas input, was taken into consideration. Drift‐flux analysis was also applied to the pipe‐flow zone, and highlighted the transition from bubbly to churn‐turbulent flow and a maximum gas void fraction operating condition of approximately 0.55. From the analysis the distribution coeffient for the downflowing system was found to be in the range 0.99–1.04, which was consistent with the measured radial void fraction profile and developed pipe flow for the two‐phase mixture.© 2003 Society of Chemical Industry
Optimising activated sludge growth rate by intensifying hydrodynamic forces
Authors: Evans G M , Liu G 
Published: February 2003

AbstractIn this study a Couette device was used to examine the influence of hydrodynamic forces on the overall behaviour of activated sludge. The specific growth rate of activated sludge increased with increasing specific energy dissipation rate, reaching a maximum rate at an energy input of approximately 40 m2 s−3, beyond which any further increases resulted in a reduction in the overall growth. At levels above about 250 m2 s−3 the specific growth rate was negligible. Experimental growth rates in the range 0.04–0.20 h−1 were obtained, depending on the energy input levels and substrate (glucose) concentration. A theoretical model successfully predicted both the decrease in the floc radius and microbial activity with increasing energy input into the system, and when combined was able to provide a reasonable prediction for the optimum specific energy dissipation rate to maximise the specific growth rate.© 2003 Society of Chemical Industry
Genetic strategy for solving chemical engineering problems in biochemical engineering
Authors: Yu Huimin , Shi Yue , Yin Jin , Shen Zhongyao , Yang Shengli 
Published: February 2003

AbstractGenetic manipulation can be used to solve some traditional chemical engineering problems in biochemical engineering such as in poly(β‐hydroxybutyrate) (PHB) production. To reduce the high production costs of PHB resulting from expensive raw materials, low productivity of the process and complexity of recovery steps, PHB biosynthetic genes (phbCAB), Vitreoscilla globin gene (vgb) and lytic genes of phage λ with an S amber mutation (S−RRz) were simultaneously introduced into the same recombinant Escherichia coli, VG1 (pTU14). This will have the advantages of using phbCAB with cheap raw materials and accumulating a high content of PHB, with the ability of vgb to enable a higher specific oxygen uptake rate by the cells, and the characteristics of S−RRz to realize controllable cell lysis. In the fermentation of VG1 (pTU14), starch hydrolysate was used in place of glucose as a cheaper carbon source, and a PHB concentration and productivity as high as 167.6 g dm−3 and 3.05 g dm−3 h−1 were easily realized at almost zero levels of dissolved oxygen (DO), and with a simple temperature‐inducing treatment for recovery PHB with a purity of at least 95% was easily harvested.© 2003 Society of Chemical Industry
Optimal operation of reactive simulated moving bed and Varicol systems
Authors: Yu Weifang , Hidajat K , Ray Ajay K 
Published: February 2003

AbstractIn this article, the performance of a reactive Simulated Moving Bed (SMB) and its modification, the more flexible Varicol process, is improved for the synthesis of methyl acetate (MeOAc) ester by multi‐objective optimization using Non‐dominated Sorting Genetic Algorithm (NSGA). The Varicol process is based on a non‐synchronous shift of the inlet and outlet ports instead of the synchronous one used in the traditional SMB technology. The optimization problems considered are both two‐ and three‐objective function problems. In one case, optimization was aimed at simultaneous maximization of the purity of MeOAc and minimization of adsorbent (and catalyst) requirement for the reactive SMB; while in the other case, maximization of purity and yield of MeOAc together with minimization of eluent (methanol) consumption for both reactive SMB and Varicol systems were considered. When the optimal solutions were compared, it was found that reactive Varicol systems could produce a higher purity product for a fixed yield, and consume slightly less eluent in the high purity region than more rigid SMB systems.© 2003 Society of Chemical Industry
VOC–air separations using gas membranes
Authors: Everaert Kim , Degreve J , Baeyens Jan 
Published: February 2003

AbstractVolatile organic components (VOC) are commonly emitted from chemical processes, ranging from dilute to concentrated streams. Membrane separation techniques are gaining increasing interest and acceptance for the recovery of VOCs. Various thin film composite membranes were experimentally assessed for the separation of gases and vapours. The membranes were used in a flat sheet configuration with a dense elastomeric silicone as the top layer on a porous polyether‐imide (PEI) or polyvinylidene‐fluoride (PVDF) support. Experimental results for pure substances and for binary mixtures were used to determine the permeability as a function of temperature and to calculate the selectivity towards nitrogen. Different models are available in the literature to predict the permeability of hydrocarbons and in this paper the free‐volume model is evaluated. The predictions from this model overestimate the experimental permeabilities, even after corrections through integrating the concentration polarisation and resistance of the porous support. A design method is developed to calculate the necessary surface area of the membrane separation module for a given flow rate, concentration, operating temperature and pressure, and the characteristic (experimental) permeability and selectivity of the membrane. This design is applied as an example to a butane–air system. Finally, current industrial applications are briefly reviewed.© 2003 Society of Chemical Industry