Film Reactor Research Articles

Application of Mathematical Modeling for Optimization of Linear Alkylbenzenes Sulphonation Modes in Film Reactor

The methodological aspects of development and application of mathematical modeling system for optimization of multistage petrochemical production on the example of linear alkylbenzene sulphuric acids obtaining complex processes at LLC “KINEF” were reviewed. It was shown that creation of mathematical modeling system includes a sequence of reaction network development stages, reactor kinetic modeling, model theoretical and experimental studies, studying regularities of reactor modes and proposing recommendations for raw material composition improving.

Performance evaluation of various bioreactors for methane fermentation of pretreated wheat straw with cattle manure

AbstractThis paper examines the performance results of configured semi-continuous mesophilic bioreactors for methane fermentation of pretreated wheat straw co-digested with cattle manure. The semi-continuous process was carried out in three different types of bioreactors, i.e. continuous stirred tank reactor (CSTR), fixed film reactor (FFR), and conventional floating drum reactor (CR), with an organic loading rate of 2.2 kg of volatile solids (VS)/day. The observed results revealed that the configuration of the FFR increased the methane production yield by 41.1%. However, the configuration of the CSTR had only a marginal effect on enhancement of methane production yield (yield increased only by 10.6%) compared to the CR. The VS removal for digesters did not vary much at the same organic loading rate. The study revealed that the pretreated wheat straw with the FFR had yield methane production of 0.342 m

Photonic contacting of gas–liquid phases in a falling film microreactor for continuous-flow photochemical catalysis with visible light

A microstructured falling film reactor was applied to the dye-sensitized photochemical conversion of 1,5-dihydroxynaphthalene to juglone for reactor and process evaluation.

Modeling of a falling-film photocatalytic reactor: Fluid dynamics for turbulent regime

The falling-film photocatalytic reactor is a photochemical device used for several environmental applications due to its simple buildup and its high solar radiation usage. As most of photocatalytic reactors, modeling the falling film photoreactor can be a challenging task. The most difficult aspect of modeling is the photon absorption by the solid catalyst. Nonetheless, modeling the fluid dynamics in turbulent regime of a falling film reactor can also be very demanding. In this work, the eddy viscosity approach was applied for estimating the average velocity profile and the film thickness for turbulent regime. Also, a sensitivity analysis was made for determining how different variables like: flow rate, tilting angle and fluid viscosity, affect to the average velocity profile and the film thickness. As remarkable results, it was found that the flow rate was the most significant operating variable and affects both considered parameters. The model was validated with experimental measurements of the film thickness at three different flow rates. The relative errors between the experimental values and the film thickness values estimated with the model can be considered as plausible, since the maximum was 13.06%. However, regarding to the local volumetric rate of photon absorption (LVRPA) estimation from the calculated and experimental values of the film thickness, the errors were negligible. According to previous works, high flow rates ensure the turbulent regime and therefore, the mass-transfer limitations due to catalyst settling can be avoided; but also with larger film thicknesses can reduce the photon absorption because of longer optical paths. So, the optimization of the photon absorption, based on the film thickness and restricted to the turbulent regime, is a necessary study that can be developed in a future work.

Investigation on the removal of the major cocaine metabolite (benzoylecgonine) in water matrices by UV254/H2O2 process by using a flow microcapillary film array photoreactor as an efficient experimental tool

A microcapillary film reactor (MCF) was adopted to evaluate and compare the removal efficiency of benzoylecgonine (BE), an emerging micropollutant deriving from illicit drug abuse (cocaine), in different aqueous matrices: milliQ water, synthetic and real wastewater and surface water. The removal processes investigated were the direct photolysis with UV radiation at 254 nm, and the advanced oxidation process (AOP) with the same UV radiation and hydrogen peroxide. As a result of the microfluidics approach developed through an innovative experimental apparatus, full conversion of BE was reached within a few seconds or minutes of residence time in the MCF depending on the process conditions adopted. The radiation dose was estimated to be approximately 5.5 J cm−2. The innovative MCF reactor was found to be an effective tool for photochemical studies, especially when using highly priced, uncommon, or regulated substances. The removal efficiency was affected by the nature of the aqueous matrix, due to the presence of different xenobiotics and natural compounds that act primarily as HO• radical scavengers and secondly as inner UV254 filters. Moreover, nano-liquid chromatography (LC)-high resolution-mass spectrometry analysis was utilized to identify the main reaction transformation products, showing the formation of hydroxylated aromatics during the photochemical treatment.

Kinetics of Chromium(VI) Reduction with Acetate Biodegradation byEscherichia coli33456 in a Fixed Biofilm Reactor

Abstract A kinetic model was developed to describe the Cr(VI) reduction with acetate biodegradation by Escherichia coli 33456 in a fixed film reactor. A laboratory-scale column reactor was used to verify the model system. Batch kinetic tests were independently performed to determine biokinetic parameters used in model simulation. With assumed values of initial biofilm thickness (Lf0), the mathematical model simulated well experimental results for effluent concentrations of Cr(VI) and acetate, suspended E. coli cells, and Cr(III) production. The concentration of suspended E. coli cells reached 11.4 mg cell/L while the thickness of attached E. coli cells was estimated to be 27.8 μm at a steady state condition. At steady state, removal efficiencies of Cr(VI) and acetate were about 92% and 90%, respectively, under influent Cr(VI) loading rate (11.3 g/[m3·day]) and acetate loading rate (664.4 g/[m3·day]) at a hydraulic retention time of 10.7 h, while the effluent concentration of Cr(III) was ∼1.65 mg/L. The ki...

English

Activated Carbon prepared from Sugarcane Bagasse(SC) was selected as the suitable adsorbent for CO2 sequestration and an experimental analysis was carried out to study the effectiveness of adsorption of the vehicular exhaust on the adsorbent. The adsorbent was prepared by slow pyrolysis of Sugarcane Bagasse at 600oC. Because of the increasing level of greenhouse gases in the atmosphere due to our dependence on fossil fuels, the need to create a cost efficient,reusable material with a high CO2 adsorption capacityhas become necessity. In this paper the FTIR analysis of the SC600oC was carried out. The vehicular exhaust was injected into a thin film reactor after H2S removal. The effectiveness of adsorption was tested at an emission testing centre while removal of H2S was tested by simple qualitative analysis.

Investigation on up-flow anaerobic sludge fixed film (UASFF) reactor for treating low-strength bilge water of Caspian Sea ships.

BackgroundIn order to meet the International Maritime Organization (IMO) objectives, the main purpose of this study was using the cheap and practical wastewater treatment system for low-strength bilge water of Caspian Sea ships; therefore, the low-strength bilge water of the Caspian Sea ships has been treated by up-flow anaerobic sludge fixed film (UASFF) reactor at the ambient temperature.ResultsThe reactor operated at two hydraulic retention times (HRTs) of 10 h and 8 h. The organic loading rates (OLR) ranged (0.12-0.6) g chemical oxygen demand (COD)/l.day. At the beginning of the experimental procedure, the sludge was immobilized on the surface of the support materials. After 10 days of batch feeding of the reactor with the wastewater as an acclimation period (with COD removal of 59%), the reactor operated continuously. At the end of the experiment, with the HRT of 8 h and OLR of 0.6 g COD/l.day, the COD and total suspended solid (TSS) removal efficiencies reached the amounts of 75% and 99%, respectively. In addition to the good features of the reactor in removing COD and TSS, the effluent oil concentration was significantly lower than the standard value (15 ppm) which has been laid down for the discharge of the bilge water from ships by the IMO.ConclusionsThe obtained data demonstrated that UASFF reactor is an appropriate system for treatment of a low-strength bilge water.

Effective denitrification process by a low voltage in a multi-cathode bio-electrode film reactor

An outstanding nitrate removal rate of 16.8 NO3−–N mg L−1 h−1 was achieved by applying voltage of 0.25 V in a multi-cathode bio-electrode film reactor.

Nanoporous gold film: fabrication and role as a catalytic reactor.

Nanoporous gold (NPG) is attractive due to its high catalytic activity. From an applied and economical point of view, fabricating thin NPG films is recognized to be an ideal approach. Herein, we report an interesting finding that a thin NPG film with a thickness of 90 nm can be prepared on various substrates conveniently by using seed-mediated growth. The film has a nanoporous character with 30-60 nm and 10-30 nm of ligament and pore size, respectively. The high cost-efficiency, adjustable substrates, easy and convenient operation make this film reactor a good candidate for catalyzing both oxidative and hydrogenation reactions.

Performance of up flow anaerobic sludge fixed film bioreactor for the treatment of high organic load and biogas production of cheese whey wastewater

Among various wastewater treatment technologies, biological wastewater treatment appears to be the most promising method. A pilot scale of hybrid anaerobic bioreactor was fabricated and used for the whey wastewater treatment. The top and bottom of the hybrid bioreactor known as up flow anaerobic sludge fixed film (UASFF); was a combination of up flow anaerobic sludge blanket (UASB) and up flow anaerobic fixed film reactor (UAFF), respectively. The effects of operating parameters such as temperature and hydraulic retention time (HRT) on chemical oxygen demand (COD) removal and biogas production in the hybrid bioreactor were investigated. Treatability of the samples at various HRTs of 12, 24, 36 and 48 hours was evaluated in the fabricated bioreactor. The desired conditions for COD removal such as HRT of 48 hours and operation temperature of 40 ?C were obtained. The maximum COD removal and biogas production were 80% and 2.40 (L/d), respectively. Kinetic models of Riccati, Monod and Verhalst were also evaluated for the living microorganisms in the treatment process. Among the above models, Riccati model was the best growth model fitted with the experimental data with R2 of about 0.99.

Gas–liquid dielectric barrier discharge falling film reactor for the decoloration of dyeing water

AbstractBACKGROUNDDecoloration of dyes is a top priority to enhance biodegradability in color‐free wastewater post‐treatment. A gas–liquid dielectric barrier discharge (DBD) falling film reactor has been developed as a promising approach to the decoloration of dyes.RESULTSRhodamine B was employed as a model compound. The effects of residence time of the liquid film with different initial concentrations, oxygen flow rates and oxygen concentrations (using different diluent gases, e.g. argon and nitrogen) were investigated. Longer liquid film residence time and lower oxygen flow rate resulted in higher decoloration efficiency. The decoloration efficiency in oxygen and nitrogen discharge was slightly higher than that in oxygen and argon discharge at the same oxygen concentration. The mechanisms of decoloration and the production of oxidative species are clearly revealed. The highest decoloration efficiency (up to 97.4%) with initial concentration of 50 mg L−1 was obtained in pure oxygen discharge with liquid residence time of 1.9 s at an oxygen flow rate of 100 mL min−1.CONCLUSIONThe proposed gas–liquid DBD falling film reactor is a promising alternative to advanced oxidation processes (AOPs) for effective treatment of dyes. These results are helpful for further real plasma wastewater treatment. © 2014 Society of Chemical Industry

CFD Simulation of UV Disinfection Reactor for Applesauce with a Low UV Absorption Coefficient

In this study, a Computational Fluid Dynamics (CFD) model was developed to evaluate ultraviolet disinfection applesauce reactor. To simulate UV reactors, three sets of equations, including hydrodynamics, radiation and species mass conservation were solved simultaneously. The Realizable k-e turbulence model and the discrete ordinate method were used to find the UV radiation profile through the reactor. Using the Chick-Watson kinetic model and the Eulerian framework, inactivation of applesauce microorganisms was simulated in the UV reactor. Simulation results for water disinfection in the UV reactor were evaluated by the reported experimental data. Simulation was extended for non-Newtonian fluid such as applesauce. Results show that the UV reactor is less effective in eliminating microorganisms from applesauce than from water because applesauce has a higher UV absorption rate. In order to achieve higher disinfection of the UV reactor for non-Newtonian fluids with high absorption, this study examined different parameters and makes suggestions for appropriate reactor design. Different designs for disinfection reactor were studied, due to higher UV absorption coefficient of applesauce, CFD simulations show that the inactivation of microorganisms in applesauce is less than water, consequently thin film or small radius reactors are appropriate design.

Mineralization of reactive azo dyes present in simulated textile waste water using down flow microaerophilic fixed film bioreactor

The present research emphasizes on degradation of azo dyes from simulated textile wastewater using down flow microaerophilic fixed film reactor. Degradation of simulated textile wastewater (COD 7200mg/L and dye concentration 300mg/L) was studied in a microaerophilic fixed film reactor using pumice stone as a support material under varying hydraulic retention time (HRT) and organic loading rate (OLR). The intense metabolic activity of the inoculated bacterial consortium in the reactor led to 97.5% COD reduction and 99.5% decolorization of simulated wastewater operated under OLR of 7.2kgCODm3/d and 24h of HRT. FTIR, 1H NMR and GC–MS studies revealed the formation of lower molecular weight aliphatic compounds under 24h of HRT, leading to complete mineralization of simulated wastewater. The detection of oxido-reductive enzyme activities suggested the enzymatic reduction of azo bonds prior to mineralization. Toxicity studies indicated that microbial treatment favors detoxification of simulated wastewater.

Understanding of the liquid overflow behavior inside micro-structured falling film reactors based on a wetting approach

This study investigates the behavior of gravity-driven liquid films inside falling film micro-reactors and focuses on the conditions necessary to obtain and break-up the complete liquid overflow from all of the channels. Micro-structured falling film reactors containing 6–10 straight parallel rectangular micro-channels were designed, constructed and tested. The main objective was to show experimentally the influence of liquid wettability on the hydrodynamic behavior. To achieve this, we explored the fluidic motion as a function of several parameters, including micro-channel size, the structural materials of the reactor (stainless steel, fluorocarbon and silicon oxide), liquid nature (water, water–ethanol mixtures and aqueous solutions of a ionic sodium dodecyl sulfate surfactant) and concentration levels. The major parameters that control the hydrodynamic behavior are the liquid/solid advancing and receding contact angles. The advancing contact angle governs the filling and the overflow of the channels, while the receding contact angle drives the characteristics of the break-up of the total overflow. Through experimentation, we identified a relationship between the contact angles and the resulting liquid flow patterns. We observed that spreading increases with higher ethanol content levels, surfactant concentration or by using a silicon oxide reactor. The flow rate required to achieve or break-up the total overflow decreased as a result. Finally, all of these results can be summarized by two master curves relating the critical flow rates to achieve and break-up the overflow with the advancing and receding contact angles, respectively. The channel dimensions also play a role in the hydrodynamic behavior, since the reduction of the channel width and distance between successive channels leads to a decrease in the critical flow rates.

Research on UV/TiO2 Photocatalytic Oxidation of Organic Matter in Drinking Water and its Influencing Factors

UV/TiO2 photocatalytic of filtrated water are conducted in S waterworks which take Yangtze River as its source water in Nanjing. Self-made glass supported nano-TiO2 film and photocatalytic reactor are used for the experiment. Results show that TOC removal efficiency can reached 45% -63% within 2h-3h, Organic matter removal efficiency is positively related with the • OH generated in photocatalytic process. The influence factors on TOC removal efficiency follows the sequence: light intensity, dissloved oxygen, reaction time and pH. Changes of UV absorption characteristics in photocatalytic process indicate that the saturation of organic matter increase significantly, this is conductive to control the risk taken by disinfection by-products. Results proved that UV/TiO2photocatalytic is a promising technology for the removal of organic pollutants in drinking water, it can improved the chemical safety of drinking water.

Microbial Treatment of Domestic and Industrial Wastes for Biological Hydrogen Production

In view of increasing rates of waste generation, managing waste by converting it into energy is a promising solution. Hydrogen, a high-level energy fuel (122KJ/g), shows the most potential as it can be produced from biological wastes. In the anaerobic digestion process, a large amount of hydrogen is produced by various microbes (potentially 400L to 100L of H2/kg dry matter), which is rarely detectable in final product that is biogas. This hydrogen gas needs to be extracted by allowing proper separation of the phases of this process. The efficiency of this process can also be enhanced through improved reactor designs like the Anaerobic Hybrid reactor, Fixed Film reactor and Upflow Sludge Bed reactor. National initiatives like MNES and NMP will also help in making this technology available for large-scale use.

Modeling and simulation of an industrial falling film reactor using the method of lines with adaptive mesh. Study case: Industrial sulfonation of tridecylbenzene

The method of lines with adaptive mesh was used to solve a falling film reactor model for the industrial sulfonation of tridecylbenzene. A model composed by three partial differential equations, three ordinary differential equations and several arithmetic ones was proposed. Using a discretization of 60 nodes in radial direction, the percentage of error respect to plant data in terms of exit liquid mean temperature and SO3 conversion was 0.03% and 1%, respectively. Temperature distribution in the liquid film aided to detect hot zones in the falling film near the entrance of the reactor, reaching an increase of ca. 36K in the hottest point. The behavior of the reaction along the reactor was also studied based on the conversion profile and concentration distribution in the liquid film. The model allows performing a complete analysis of the reactor operation, making the model and its results a useful tool for the industry.

High-rate fermentative hydrogen production from palm oil mill effluent in an up-flow anaerobic sludge blanket-fixed film reactor

The major problem associated with UASB reactors for biotransformation of organic matter to hydrogen is the long start-up period (2–4 months) required for the growth of the microbial granules. In this study, an integration of granular sludge system and a fixed film reactor in a single reactor was applied to overcome this problem. An up-flow anaerobic sludge blanket-fixed film (UASB-FF) reactor was initially inoculated with heat pretreated seed sludge as inoculum and operated as closed-loop fed-batch for five days (HRT=24h; 38°C; pH 5.5). The reactor was continuously fed with fresh pre-settled POME in order to shorten the start-up period. The organic loading was gradually increased from 4.7 to 51.8g/Ld. Granular sludge rapidly developed within 22 days. Specific hydrogen production rate was 0.514LH2/gVSSd at the end of the start-up period. Speedy development of bio-granules was attributed to biomass recirculation and the establishment of a fixed film at the upper section of the UASB-FF reactor that resulted in improved interactions among the bacterial consortium.

Green Photochemical Processes and Technologies for Research & Development, Scale‐up and Chemical Production

AbstractPhotochemistry is often viewed as a green chemical method since photons are regarded as a ‘clean and traceless reagent’. Despite this, photochemical transformations generally suffer from a variety of ‘non‐green’ drawbacks that have prevented their widespread adaptation in chemical manufacturing. These include the necessity for hazardous solvents, low quantum yields of photochemical transformations, high energy demands of traditional lamps and the need for high dilution due to the low penetration of light into the reaction mixture. As a result, photochemical operations generate large volumes of hazardous solvent waste, demand prolonged irradiation times and require high energy inputs. This highlight article shows recent examples of green photochemical processes and technologies that overcome these limitations. These include photodecarboxylations in water matrices with high quantum yields in an advanced 308‐nm excimer falling film reactor, solar photooxygenations utilizing concentrated sunlight generated in a parabolic trough loop and photosensitized additions in resource‐efficient microreactors under continuous flow conditions. The results show that photochemistry can be implemented as a truly green methodology across the entire chemical process spectrum from early R&D to scale‐up and subsequently production.