Pilot Plant Scale Reactor Research Articles

Improved creep performance of melt‐extruded polycaprolactone/organo‐bentonite nanocomposites

AbstractIn this work, biodegradable nanocomposites based on polycaprolactone reinforced with pristine and organo‐modified bentonites are prepared by melt extrusion. Bentonite is exchanged with benzalkonium chloride (CBK) in a pilot plant scale reactor. The influence of clay type and loading on morphology, rheology, mechanical properties, and creep performance of the resulting materials is analyzed. Besides, several theoretical models then applied to experimental creep data and master curves are used to relate time and temperature with the compliance of the materials. The morphology characterization of the nanocomposites show that the organo‐modification of the clay greatly improves its dispersion in the polymer matrix. As a consequence, it is demonstrated that reinforcement of PCL with 3 wt% loading of organoclay produces the strongest improvement in creep resistance. The instantaneous creep strain and the experimental creep rate decrease more than 9% and 27%, respectively, in the range of temperatures analyzed. Moreover, the experimental values are used to adequately fit theoretical creep models for different clay loadings. On the other hand, the material with optimal creep behavior also shows the greatest improvements in tensile mechanical properties.

Direct Phosphorylation of Psilocin Enables Optimized cGMP Kilogram-Scale Manufacture of Psilocybin.

A second-generation kilogram-scale synthesis of the psychedelic tryptamine psilocybin has been developed. The synthesis was designed to address several challenges first encountered with the scale-up of previously described literature procedures, which were not optimized for providing consistent yield and purity of products, atom economy, or being run in pilot plant-scale reactors. These challenges were addressed and circumvented with the design of the second-generation route, which featured an optimized cGMP large-scale Speeter–Anthony tryptamine synthesis to the intermediate psilocin with improved in-process control and impurity removal over the three steps. Psilocin was subsequently phosphorylated directly with phosphorous oxychloride for the first time, avoiding a tedious and poor atom economy benzyl-protecting group strategy common to all previously described methods for producing psilocybin. In this report, the challenges encountered in a 100 g scale first-generation literature-based synthesis are highlighted, followed by a detailed description of the newly developed second-generation synthesis to provide over one kilogram of high-purity psilocybin under cGMP.

Hydrogen generation by irradiation of commercial CuO + TiO2 mixtures at solar pilot plant scale and in presence of organic electron donors

A CuO + TiO2 mixture, based on two commercial and well characterized CuO and TiO2 photocatalyst, has been used to produce hydrogen by solar light irradiation and in presence of different organic compounds (methanol, glycerol, formic acid, and the components of a wastewater coming from the biodiesel industry) acting as sacrificial electron donors. The experiments have been conducted at Plataforma Solar de Almería (PSA, south of Spain) with a pilot plant scale reactor using a CPC (compound parabolic collector) configuration. The tested system has shown similar hydrogen generation capacity and energy efficiency than more expensive ones based on the use of noble metal/photocatalyst composites. Formic acid has shown to be the most effective electron donor, although very close amounts of hydrogen are also produced with glycerol, and this is found as a waste compound released in large quantities at the biodiesel industry wastewaters. As seen in previous similar studies, the increase of solution conductivity hampers the hydrogen generation, and a slightly basic solution pH (pH≈9) gives the best reaction conditions. Finally, the composite can be recovered and successfully reused giving the ensuing and sustained generation of H2 while removing more than 50% of TOC.

Comprehensive investigation and comparison of TFM, DenseDPM and CFD-DEM for dense fluidized beds

Eulerian-Eulerian and Eulerian-Lagrangian models are widely applied to numerically investigate dense solid-gas fluidized bed systems. However, only a few studies in the existing literature focus on a detailed analysis and comparison of the different modeling approaches. Therefore, the objective of this study is to investigate the Two Fluid Model (TFM), the Dense Discrete Phase Model (DDPM), and the Computational Fluid Dynamics-Discrete Element Method (CFD-DEM) with respect to a comprehensive independency study, a sensitivity analysis of the respective submodels and model parameters, a comparison of the simulation results between the different modeling approaches, as well as their computational demand. The simulations represent a test case of a pilot plant scale reactor (inner diameter up to 387 mm, height 900 mm), which is used within a thermochemical energy storage system (CaO+H2O↔CaOH2). Monodisperse Geldart B powder (particle diameter 200 μm, particle density 2500 kg/m3, sphericity factor 0.8) is fluidized with water vapor (ideal gas, temperature 400 °C, inlet velocity 0.495 m/s). Grid size, fluid and particle time step, and particle clustering are considered for the independency study. Different wall boundary conditions and calculation methods for the granular temperature are investigated for the TFM. For the DDPM, different wall boundary conditions are analyzed as well, while for the CFD-DEM, simulations with two different DEM submodels (Hertzian and Hookean collision model) and a sensitivity analysis of the respective model parameters are included. Results show that the TFM and the CFD-DEM are able to predict qualitatively and quantitatively similar gas and particle flow fields, if TFM model parameters are set appropriately. However, a quite different pressure drop and bed expansion is observed for each model. The DDPM does not result in realistic flow fields for the investigated test case, despite predicting a pressure drop and bed expansion similar to the TFM. The presented findings lead to the conclusion that model validation should not only be based on global observable values like pressure drop and bed expansion, but also on local particle flow fields and bubbling behavior.

Manufacturing demonstration of microbially mediated zinc sulfide nanoparticles in pilot-plant scale reactors.

The thermophilic anaerobic metal-reducing bacterium Thermoanaerobacter sp. X513 efficiently produces zinc sulfide (ZnS) nanoparticles (NPs) in laboratory-scale (≤24-L) reactors. To determine whether this process can be up-scaled and adapted for pilot-plant production while maintaining NP yield and quality, a series of pilot-plant scale experiments were performed using 100-L and 900-L reactors. Pasteurization and N2-sparging replaced autoclaving and boiling for deoxygenating media in the transition from small-scale to pilot plant reactors. Consecutive 100-L batches using new or recycled media produced ZnS NPs with highly reproducible ~2-nm average crystallite size (ACS) and yields of ~0.5gL(-1), similar to the small-scale batches. The 900-L pilot plant reactor produced ~320g ZnS without process optimization or replacement of used medium; this quantity would be sufficient to form a ZnS thin film with ~120nm thickness over 0.5m width × 13km length. At all scales, the bacteria produced significant amounts of acetic, lactic, and formic acids, which could be neutralized by the controlled addition of sodium hydroxide without the use of an organic pH buffer, eliminating 98% of the buffer chemical costs. The final NP products were characterized using XRD, ICP-OES, TEM, FTIR, PL, DLS, HPLC, and C/N analyses, which confirmed that the growth medium without organic buffer enhanced the ZnS NP properties by reducing carbon and nitrogen surface coatings and supporting better dispersivity with similar ACS.

Seeded Semibatch Emulsion Copolymerization of Styrene, Butadiene, and Carboxylic Acids in a Pilot Plant Reactor

The seeded semibatch emulsion terpolymerization of styrene–butadiene–acrylic acid is investigated in a pilot plant scale reactor of 151 L. The effect of the styrene–butadiene ratio (S/BD ratio), amount of tertiary-dodecyl mercaptan as chain transfer agent (CTA), and two temperature profiles on the kinetics of the process (solids content, styrene conversion, particle size, and acid partitioning), by-product formation (4-phenyl cyclohexane, 4-PCH, and 4-vinyl cyclohexane, 4-VCH) and the molar mass distribution of the sol and the fraction of gel are studied.

SCR catalyst coated on low-cost monolith support for flue gas denitration of industrial furnaces

NH3–SCR honeycomb catalyst was prepared by coating powdery active metal components on the surface of blank monolith supports and tested at the temperatures of 250–350°C, and superficial gas velocities of 5.3–6.3m/s. The tests were performed with a simulated gas mixture containing NO, SO2, O2, H2O and N2 or a real flue gas produced on line. The results showed that the coated honeycomb catalyst has an extraordinary high activity for low-temperature deNOx in the presence of 5vol.% steam and 1000ppm SO2. Its activity increased with increasing the coating thickness and reached at 110μm thickness as comparable as that of the 100% active components-molded catalyst, suggesting the deNOx reaction proceeded mainly in the surface layers of the honeycomb cell wall and hence coated honeycomb catalyst should be more cost-efficient than 100% active components-molded one. In a real coal-burned flue gas stream the catalyst maintained essentially its low temperature activity and stability, further verifying its high industrial applicability. Then, the effects of NO concentration and NH3/NO ratio on NO conversion were investigated to seek a suitable kinetic model for prediction of the catalyst’s deNOx rate and reactor design for pilot plant research. The data obtained showed that a simple power-law kinetic equation with first order in NO and zero order in ammonia can be applied to the coated honeycomb catalyst, and was used for determination of the kinetic parameters. Finally, simulation calculation was performed under arbitrary conditions to provide valuable information for design of pilot-plant scale reactors.

Understanding coal/hydrocarbons pyrolysis in thermal plasma reactors by thermodynamic analysis

This work aims to improve the understanding on the principles of coal/hydrocarbons pyrolysis to acetylene (C2H2) in thermal plasma reactors by thermodynamic analysis in association with the practical operation experience at lab- and pilot-plant scale reactors. The thermodynamic predictions agree well with the experimental data in the literature and the representative data in megawatts plasma reactors. Accordingly, it is summarized that the effective mass ratio of C/H (RC/H) in the gas phase and the quench temperature are the two key factors influencing the reactor performance. The C2H2 concentration is very sensitive to the quench temperature varying around 1500–1800 K, which is therefore suggested to maintain above 1800 K for a better yield of C2H2. Higher effective mass ratio of C/H would have a more positive effect on the reactor performance in terms of C2H2 concentration. The additional input of hydrocarbons to the reaction system provides an effective means to flexibly adjust the performance of the plasma reactor for the raised RC/H. The additional water/steam helps to inhibit coking on the wall but reduce the RC/H, leading to the trend from thermal pyrolysis to gasification process.

Energy Efficiency of Conventionally-Heated Pilot Plant Reactors Compared with Microwave Reactors

We report on the energy usage required for one organic reaction in two small pilot plant scale reactors of different vessel designs (both 50 L) conducted in a kilogram scale facility. The background energy consumption of the building and all supporting services was determined beforehand, and this figure used to compensate for the energy usage required for each of six pilot scale batches performed under different conditions at the 20 and 40 L scale. The energy usage data was compared between these large scale batches and with the equivalent laboratory scale batches, including several earlier microwave-heated batches (Moseley, J. D.; Woodman, E. K. Energy Fuels 2009, 23, 5438−5447). The results showed little difference in energy usage between the two pilot plant scale reactors under the different reaction conditions, except on doubling the scale which halved the energy usage per mole. However, the energy efficiency of the laboratory scale reactors was higher than the pilot scale reactors under all reaction conditions on a kilojoule/mole basis. Furthermore, the most efficient microwave reactor operating under optimal conditions was significantly more energy efficient than the pilot scale reactors even up to 40 L.

Modelling and experimental verification of a solar reactor for photo-Fenton treatment

In the present work, a novel design of a solar reactor is presented. This pilot plant scale reactor uses the UV-Visible and Near-Infrared solar radiation to promote the photo-Fenton treatment. A theoretical study and experimental verification were performed using formic acid as a model pollutant. The radiative transfer, thermal energy and mass balances equations were solved to compute the formic acid (F) and hydrogen peroxide (P) concentrations as a function of time. The spectral and broadband solar radiation incident on the reactor window was calculated from a computational code: the SMARTS2 program. Statistical estimators have been used to measure the departure of theoretical model from experimental data. A good agreement for formic acid and hydrogen peroxide concentrations, temperature and total and UV broadband solar radiation was obtained. The normalized root mean square errors (NRMSE) of the model for predicted variables were lower than 11%.

Safety aspects in modelling and operating of batch and semibatch stirred tank chemical reactors

Safety aspects in modelling of batch and semibatch stirred tank reactors as well as a model based safety analysis have been considered. Applicability of two basic types of models – i.e. the perfectly mixed reactor model and the CFD model, both formulated for laboratory scale as well as pilot plant scale reactors – has been discussed. A formulation of the appropriate reactor model, which is adequate to the considered case study has been demonstrated and tested experimentally. Particular attention has been devoted to the formulation of robust CFD models employed to simulate a performance of the stirred tank reactors. It has been found that models for perfectly mixed reactors may have quite wide range of application, while the CFD models should be definitely used in case of fast reactions, high viscosity of the reacting mixture as well as of failure leading to stopping of the impeller. The CFD models are able to predict a dynamic behaviour of reactors at any circumstances, so they can play a significant role in safety analysis carried out for industrial scale reactors, for which experimental safety tests are expensive and dangerous.

Mathematical Modelling of Catalytic Fixed-Bed Reactor for Carbon Dioxide Reforming of Methane over Rh/Al2O3 Catalyst

A one-dimensional mathematical model was developed to simulate the performance of catalytic fixed bed reactor for carbon dioxide reforming of methane over Rh/Al2O3 catalyst at atmospheric pressure. The reactions involved in the system are carbon dioxide reforming of methane (CORM) and reverse water gas shift reaction (RWGS). The profiles of CH4 and CO2 conversions, CO and H2 yields, molar flow rate and mole raction of all species as well as reactor temperature along the axial bed of catalyst were simulated. In addition, the effects of different reactor temperature on the reactor performance were also studied. The models can also be applied to analyze the performances of lab-scale micro reactor as well as pilot-plant scale reactor with certain modifications and model verification with experimental data. © 2008 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0)

Partial degradation of five pesticides and an industrial pollutant by ozonation in a pilot-plant scale reactor

Aqueous solutions of a mixture of several pesticides (alachlor, atrazine, chlorfenvinphos, diuron and isoproturon), considered PS (priority substances) by the European Commission, and an intermediate product of the pharmaceutical industry (α-methylphenylglycine, MPG) chosen as a model industrial pollutant, have been degraded at pilot-plant scale using ozonation. This study is part of a large research project [CADOX Project, A Coupled Advanced Oxidation-Biological Process for Recycling of Industrial Wastewater Containing Persistent Organic Contaminants, Contract No.: EVK1-CT-2002-00122, European Commission, http://www.psa.es/webeng/projects/cadox/index.html [1]] founded by the European Union that inquires into the potential coupling between chemical and biological oxidations for the removal of toxic or non-biodegradable contaminants from water. The evolution of pollutant concentration, TOC mineralization, generation of inorganic species and consumption of O 3 have been followed in order to visualize the chemical treatment effectiveness. Although complete mineralization is hard to accomplish, and large amounts of the oxidant are required to lower the organic content of the solutions, the possibility of ozonation cannot be ruled out if partial degradation is the final goal wanted. In this sense, Zahn–Wellens biodegradability tests of the ozonated MPG solutions have been performed, and the possibility of a further coupling with a secondary biological treatment for complete organic removal is envisaged.

Rubber tire thermal decomposition in a used oil environment

In this work several runs have been performed in order to achieve the decomposition of waste tires in a liquid medium. The liquid medium selected was used lubricant oils from different engines, i.e., another waste material that presents some problems for its disposal. Some experiments have been performed using a commercially available oil with known composition. The main objective of these runs is to perform a decomposition without emission of any possible pollutants, i.e., the products of tire decomposition being solved in used oils. In this work the process of decomposition–dissolution is studied mainly in a laboratory furnace, but some runs were performed in a pilot-plant scale reactor. The process is followed by means of the analysis of the oil at different stages.

Disinfecting E.coli Bacteria In Drinking Water Using A Novel Fluidized Bed Reactor.

Disinfecting microorganisms such as E.coli is a great concern in drinking water supply facilities around the world. Photocatalysis became an attractive technology to disinfect microorganisms due to its ability to degrade very low concentration of microorganisms without producing any harmful by-products. The use of optical fibre mesh reactors and slurry type photocatalytic reactors has been investigated by researchers around the world. It was shown that such reactors have low potential to be scaled up. An annular type fluidized bed reactor has been constructed and tested to disinfect E.coli bacteria. A specially prepared catalyst (TiO2 + Glass Bead + Zeolite) was used for this purpose. The proposed catalyst offered better degradation of E.coli compared to existing technology. Fluidization enhances the degradation of E-coli by moving the catalyst particles to the illuminated zone. E.coli degradation is tested in a similar arrangement in small scale with 100cm3 of contaminated water with the 106 E-coli/cm3. Repeated experiments were done with/without the presence of catalyst along with UV irradiation. With the presence of catalyst in the fluidized condition, the E-coli count is reduced to only 100/cm3 whereas the E-coli count after 30 minutes of UV irradiation only became 1800/cm3. The efficiency of E.coli removal is increased to 99.99% from 99.82% by using the proposed technology. Results of small scale prompted a construction of a pilot plant scale reactor and effectiveness of this reactor is being tested. Use of supported catalyst and the effective illumination of catalyst by fluidization help faster disinfection of microorganisms by this reactor. It has been found that the pilot scale is capable of degrading 84% of E.coli within 80minutes compared with 77.3% by using UV only which has capacity of handling 46 litre/min. E.coli degradation in larger scale is being tested for the first time and its result compared with only UV destruction is promising. The potential to use this method on a continuous reactor increases the potential for scale up.

NO Reduction Studies in the FCC Process. Evaluation of NO Reduction Additives for FCCU in Bench- and Pilot Plant-Scale Reactors

During FCC catalyst regeneration, part of the nitrogen in coke forms NOx, which makes up a significant part of the total NOx refinery emissions. The addition of a small percentage (≤1 wt %) of catalytic additive(s) in the FCC inventory can reduce the NOx emissions from the flue gases of the FCC regenerator. In this paper, experimental techniques are considered for evaluating, in laboratory reactors, the performance of two commercially available NOx removal additives. It has been shown that in an FCC regenerator the gas residence time and the concentration of CO in the flue gases are key parameters in controlling NOx emissions. For example, pilot plant experiments showed that the addition of a CO oxidation promoter (CP-3) in the catalytic inventory decreases the CO emissions significantly and increases the NOx emissions about 4 times. Replacement of the active CO oxidation promoter (CP-3) with an additive (XNOx) with moderate CO oxidation activity reduced the NOx emissions by 78%. Comparison of regeneratio...

Recent advances in ABE fermentation: hyper-butanol producing Clostridium beijerinckii BA101

This is an overview of the mutant strain Clostridium beijerinckii BA101 which produces solvents (acetone-butanol-ethanol, ABE) at elevated levels. This organism expresses high levels of amylases when grown on starch. C. beijerinckii BA101 hydrolyzes starch effectively and produces solvent in the concentration range of 27-29 g x l(-1). C. beijerinckii BA101 has been characterized for both substrate and butanol inhibition. Supplementing the fermentation medium (MP2) with sodium acetate enhances solvent production to 33 g x l(-1). The results of studies utilizing commercial fermentation medium and pilot plant-scale reactors are consistent with the results using small-scale reactors. Pervaporation, a technique to recover solvents, has been applied to fed-batch reactors containing C. beijerinckii BA101, and solvent production as high as 165 g x l(-1) has been achieved. Immobilization of C. beijerinckii BA101 by adsorption and use in a continuous reactor resulted in reactor productivity of 15.8 g x l(-1) x h(-1). Recent economic studies employing C. beijerinckii BA101 suggested that butanol can be produced at US$0.20-0.25 x lb(-1) by employing batch fermentation and distillative recovery. Application of new technologies such as pervaporation, fed-batch culture, and immobilized cell reactors is expected to further reduce these prices.

Hydroxylation of Phenol to Dihydroxybenzenes: Development of Artificial Neural-Network-Based Process Identification and Model Predictive Control Strategies for a Pilot Plant Scale Reactor

Experiments in a pilot-scale fixed-bed reactor system have been conducted to obtain the process input−output data for the titanium-based zeolite-catalyzed hydroxylation of phenol to dihydroxybenzenes. An artificial neural-network-based strategy has been used for identifying the process model covering the range of experimental conditions. The identified neural network model has been used to design a model predictive controller that has been tested on the experimental rig.

Effect of short chain branching on the blown film properties of linear low density polyethylene

Three linear low density polyethylene (LLDPE) resins of similar melt index and density were synthesized with different comonomers in the Unipol pilot-plant scale reactor. The molecular structure, blown film morphology, and film strength properties of the resins have been comprehensively characterized. The film dart drop impact strength of the LLDPEs increases in the order of ethylene/1-butene, ethylene/1-octene, and ethylene/1-hexene copolymers; whereas the Elmendorf tear strength of them increases in the order of ethylene/1-butene, ethylene/1-hexene, and ethylene/1-octene copolymers. The mechanical properties seem to be highly associated with the length and distribution of short chain branches and, consequently, the lamellar thickness distribution of the resins. © 1996 John Wiley & Sons, Inc.

Effect of short chain branching on the blown film properties of linear low density polyethylene

Three linear low density polyethylene (LLDPE) resins of similar melt index and density were synthesized with different comonomers in the Unipol pilot-plant scale reactor. The molecular structure, blown film morphology, and film strength properties of the resins have been comprehensively characterized. The film dart drop impact strength of the LLDPEs increases in the order of ethylene/1-butene, ethylene/1-octene, and ethylene/1-hexene copolymers; whereas the Elmendorf tear strength of them increases in the order of ethylene/1-butene, ethylene/1-hexene, and ethylene/1-octene copolymers. The mechanical properties seem to be highly associated with the length and distribution of short chain branches and, consequently, the lamellar thickness distribution of the resins. © 1996 John Wiley & Sons, Inc.