The helical electrode area was 0.101 m 2 . The anode and cathode were isolated using rubber gaskets. Six standard piezo-composite transducers having a resonance frequency of 40 kHz were driven by an ultrasonic generator of 300 W. In order to create the ultrasonic field inside the reactor, the transducers were bonded to a carbon steel plate attached to the anode (fig. 1b). An evaluation of the flow patterns of the electrochemical flow reactor (ER) and the sonoelectrochemical reactor (SER) was performed by instantaneously adding an input pulse of a non reactive tracer (KCl) to the influent while recording the conductivity of the effluent. The concentrations of tracer in the reactor effluent were recorded using a conductivity meter. The experiments were performed to obtain the exit age distribution function (E). This method is reliable when the dispersion number (N d = ) < 1.0 ;
12 Read more
Despite hydroformylation being a very efficient method for the transforma- tion of alkenes, it is not commonly employed in laboratories owing to the flammable/toxic nature of hydrogen and carbon monoxide gases and the ne- cessity of high-pressure equipment in a batch system. Flow chemistry often raises the safety profiles against high-pressure and toxic gases because the diameter of the flow reactor is small. Herein, we show that aliphatic alkenes can be safely hydroformylated in a flow reactor. In our flow method, although the target hydroformylated product was obtained in a low yield (19%), toxic gases were safely treated using a flow reactor. Better yields could possibly be achieved by recycling of the unreacted alkene.
Hydrodeoxygenation (HDO) of 5-hydroxymethylfurfural (HMF) has received a great deal of attention in the past few years because of its importance for converting biomass into petrochemical replacements. Previously, most studies on liquid-phase HDO have been performed only in batch reactors. The present work investigates the HDO reaction in a self-designed flow reacting system, which is demonstrated to be a powerful tool for kinetic studies. The data indicate that the HDO of HMF follows a sequential scheme, with HMF first reacting to partially hydrogenated intermediates. These intermediate products then form DMF, which in turn reacts further to undesired products. The HDO performance has been investigated over a large number catalysts in the flow reactor. Monometallic catalysts (Pt, Pd, Ni, Co, Ru, Ir, etc.) are generally found to be unselective, due to the over-hydrogenation of DMF through ring-opening or ring-hydrogenation. By contrast, bimetallic catalysts, especially with well-controlled particle size and metal composition, are observed to be highly selective in the HDO of HMF. Nearly 100% yields of DMF can be achieved over Pt3Co2, Pt3Ni, Pt2Zn and PtCu nanocrystal catalysts. Theoretical calculations indicate that the binding configuration of furanic intermediates change on bimetallic surfaces compared to monometallic catalyst, leading to different reaction pathways. This thesis work provides a general strategy for improving the HDO selectivity from HMF.
215 Read more
In conclusion, we have developed the monotetrahydropyranylation of symme- trical diols in a flow reactor. Stirring 1,4-butanediol, DHP, and CSA in a batch reactor for 6 - 10 min resulted in the selective formation of the monoprotected diol. However, the selectivity for monotetrahydropyranylation improved when the reaction was carried out in a flow reactor. The flow method can be applied directly to large-scale synthesis by simply numbering up the flow reactor without affecting the selectivity and yield. Studies are currently underway to develop a method to remove unreacted starting diol from flow reactors.
This study investigated the numerical simulation and experiment of a continuous indium removal process from wastewater by using an electrochemical flow reactor. The competition between hydrogen evolution and indium reduction was taken into consideration. The simulated residual indium distribution accompanying with flow field corresponds to the removal performance of experiments. The concentration field indicates a two-stage development between the electrodes. In the second stage, an apparent removal of indium takes place, but a steady state reached after a long-term incubation at a low flow rate. However, the removal ratio rises quickly and levels off after a short-term incubation at a high flow rate. At 762 mL/min, 90% or more of indium in wastewater can be removed, but only 50% or less of indium can be reduced at 7620 mL/min. The flow cell takes a compromise between throughput and efficiency if an optimal operation is adopted. The optimization on the basis of energy consumption and equipment cost shows that two flow cells in series operated at 3810 mL/min may be more economical than a unit cell at any flow rate in the influence of hydrogen evolution.
21 Read more
Figure 1 shows the temperature profiles obtained at the middle of cycle number 15 for two experiments (3600 ppm methane and switching times 100 and 300 s, respectively). In the same plots, the equivalent experiments carried out in the reactor without adsorbent and in the absence of water have also been depicted. As it has been explained, water produces an inhibitory effect on the catalyst, reducing the reaction rate. Thus, methane conversion decreases, resulting in a decrease in bed temperature, as observed when the experiment without adsorbent is compared to the experiment with no water. This effect reduces the stability of the reactor, as will be discussed later. On the other hand, the reverse flow reactor with water and integrated adsorption exhibits a temperature profile very close to the corresponding to the absence of water. This indicates that a similar amount of heat is being released by the reaction and hence the reaction is taking place at a similar reaction rate, and suggests that the adsorbent is trapping the water and preventing catalyst inhibition. These experiments demonstrate in a practical application and at bench-scale that the concept of the reverse flow reactor with integrated adsorption can be successfully implemented.
33 Read more
Wouter Stam (Flowid) gave his presentation showing the ’The benefits of Using SpinPro for Multiphase Reactions’. The SpinPro Reactor is a continuous reactor that allows chemical reactions to take place in seconds in a highly controlled and safe manner. The claim is that it performs reactions under process intensified conditions resulting in high energy and resource efficiency, improved product quality and flexibility in production and development. He did emphasise that the SpinPro Reactor is not to be confused with a ‘thin film spinning disc reactor’. The SpinPro Reactor is another type of spinning disc reactor (rotor-stator type). Significantly large shear rates in the gasses and liquid can be induced, which in turn leads to a much larger interfacial area available for mass transfer and a higher degree of turbulence and micro mixing. In addition, the volume of the reactor is completely filled with liquid. The SpinPro technology is well suited for multiphase chemistry, liquid-gas, liquid-liquid or combinations. Furthermore, it can handle precipitation reactions and controlled emulsifications.
discrepancy ( ∼ 11 % difference) in bulk SOA hydroxyl and carbonyl functionalities, possibly a result of the high VOC mixing ratios used. However, aliphatic, nitrate and aromatic nitro functionalities all displayed relatively good agreement. It is important to note that the objective of this study was not to mimic atmospheric conditions but to provide a tool that allowed the use of highly accurate techniques to gain greater insights into the chemical and physical properties of SOA. Nevertheless, the elemental composition of the gen- erated SOA displayed good agreement with literature val- ues, suggesting that, for the experimental conditions inves- tigated, the bulk elemental composition is largely unaffected by the use of high VOC mixing ratios. The SOA generated from two replicate experiments displayed excellent agree- ment, with measured O/C and H/C ratios within the error of the analytical instrumentation. Using the methods described, we were able to quantify up to 36 % of α-pinene SOA, which is a considerable improvement from most previous studies. We must stress that the developed CFR design will require modification to the UV light source for applications focused on replicating atmospheric conditions. The current UV light source is not sufficient for the reactor size, resulting in pho- tochemically dark space within the reactor. The CFR costs GBP ∼ 8000 to build, including the reactor housing. A con- siderable proportion of this cost is attributed to use of several mass flow controllers costing GBP ∼ 6500. The mass flow controllers can be substituted for cheaper alternatives (e.g. ball flow meters), which will significantly reduce the cost. However, due to the reduced accuracy in the flow rates of these alternatives methods, the CFR will need to be oper- ated at low flow rates (less than ∼ 4 L m −1 ) and the reactor volume closely monitored. The CFR is incredibly versatile. Multiple instruments can be connected to the reactor and eas- ily interchanged. Different oxidants and/or scavengers can be introduced into the reactor and mixed VOC experiments can be performed (i.e. introduction of two VOCs). The CFR can also be designed to be more sophisticated with a simple ad- dition of a software program (using DAQFactory, or simi- lar) for the automated control of the mass flow controllers. This work demonstrates how the unconventional use of a newly built CFR can be used to gain considerable insights into the chemical and physical properties of SOA, providing a greater understanding of the relationship between SOA for- mation conditions, chemical composition and physicochem- ical properties.
23 Read more
and inlet manifolds, spirals and flow channels of the five cells that form the stack. p was measured at mean linear flow rate within the range of 0.26–12.5 cm s − 1 for the bromine compart- ment. Pressure sensors were located in T-pieces in the external manifold of the cell (see Fig. 2) and the data were monitored and stored with a purpose built data acquisition program run from a PC. Fig. 6 shows the logarithmic plot of pressure drop as a func- tion of the logarithm of the mean flow velocity. p across the bromine compartment was higher than the pressure drop across commercially available reactor, such as the FM01-LC; this is mainly due to the flow restrictions imposed by the spirals in the manifold which are important in minimizing bypass currents [40,41].
A sensitivity analysis was done in Aspen Plus model to investigate the effect of reactant flow rates towards the how the mole fractions of sodium acetate vary for different flow rates of NaOH and ethyl acetate. It shows that in each case the highest mole fraction of sodium acetate can be achieved when equal flow rates of NaOH and flow reactor. According  it is clear that equal amounts of reactants are needed to obtain the highest yield. 3. Volume Comparison of CSTR and PFR
To investigate the efficiency of the reactors, the Electrical Energy per contaminant degradation Order (EEO) is computed for different contaminant rates. Fig. 9 shows the EEO for annular and cross flow reactors with different contaminant rates. As it is expected, it is shown that the EEO reduces significantly by increasing the contaminant rate constant. Moreover it is found that the EEO of annular reactor is about 3 times greater than the cross flow reactor. This is due to the fact that the cross flow reactor have larger cross section (the volume of the cross flow reactor is greater than the annular reactor) and thus the velocity of the water in the cross flow reactor is smaller than the annular flow reactor. So the residence time of the particles in cross flow reactor is greater and the contaminants are disinfected more efficiently. Also it is found that unlike TCEP ( k TCEP = 5.6 10 × 8 M s − − 1 1 ) which at 50 mg/L initial hydrogen peroxide concentration requires an EEO ranging from 0.511 (cross-flow reactor) kWh/m 3 to 1.407 (parallel-flow reactor) log TCEP -1 , the
The Fischer-Tropsch synthesis in a packed-bed reactor over an industrial Fe- Cu-K catalyst was modeled using a non- isothermal, one-dimensional flow reactor intrinsic reaction kinetics for both the Fischer-Tropsch and water-gas shift reactions over the above catalyst were obtained from literature and tested against the reported experimental data. Genetic algorithm optimization method was used to obtain the optimum conditions that would maximize the C 5+ product yield. The
11 Read more
Abstract— in this study dairy waste water is collected from belagavi milk union limited (BMUL) located at belagavi district. The dairy waste water industry effluents have high pH, BOD, Total solids, organic and inorganic contents such wastewater, if discharged without proper treatment, severely pollutes receiving water bodies. To treat this dairy wastewater, the Hybrid Down flow Aerobic Trickling Filter Bed (DATFB) reactor is developed. In this study packing Medias are used such as recycle coarse aggregate, polypropylene pall rings, and steel scrubber. The pilot scale setup was operated for varying different HRT’s of 72hours, 48hours, 24hours, 18hours, 12hours, 06hours with the different flow rate. The results obtained from this experimental study showed removal efficiency for BOD as 87.54%, alkalinity 47.11%, chlorides 49.68% , Total solids 78.64% , Total dissolved solids 79.08% , Total suspended solids 77.47%, for optimum HRT 24hours and the pH ranges from 7-10 in the final concentration. From the above results it is concluded that the Hybrid DATFB reactor gives more efficiency and good results. The filter media which is used in this reactor gives more than 80-90% efficiency in these results.
10 Read more
“Excitable” or “active” media occur widely in biological systems. Waves of “excitation” are used for signal transmission or for synchronising reaction events. Important examples of excitable media include cardiac muscle and neuronal tissue. Methods for studying biological systems in vivo are developing, but in many cases it is possible to determine generic features by investigating model systems such as chemical analogue systems. The Belousov-Zhabotinsky (BZ) reaction is widely used in this respect. Several groups in the REACTOR programme have experience of such studies both in experiment and modelling. Re- cently, certain “universal relation- ships” underlying the dynamics of “spiral wave” structures (thought to be important in the onset of ventricu- lar fibrillation, for instance) have been proposed and tested. The influ- ence of electric and magnetic fields on wave propagation in these systems is one of the features being investigated.
4.1. Effect of Relative Resin Velocity Factor The value of may be increased by either increasing the superficial resin velocity; i.e. the amount of resin flowing per unit cross sectional area per unit time, or by either decreasing the resin density or the fractional holdup of solids in the reactor. This in turn means either higher resin velocity (i.e. smaller contact time between solute and resin) or the presence of fewer resin particles in the column in a specific time so that less ions will be adsorbed on the resin surface. This is shown in Figure 2 as the conversion extent decreases with increasing the relative resin velocity factor, which in turn requires lar- ger column height. For example at a four-meter column height the estimated percentage conversion reached with a relative resin velocity factor of 7.1 × 10 −3 m/s is 33.4%,
10 Read more
The FBBR, the attached growth type of reactor (system), is a recent process innovation in wastewater treatment, which utilizes small, fluidized media for cell immobilization and retention [37, 54]. Main application of the FBBR is in the field of biological treatment of wastewater. Aerobic as well as anaerobic FBBRs have received increasing attention for being an effective technology to treat water and wastewater [55, 51, 50, 35, 26, 38, 18, 52, 4, 42, 8]. Its most important features are - the fixation of microorganisms on the surface of small- sized particles, leading to high content of active microorganisms and large surface area available for reaction with the liquid; the high flow rate (low residence time) which can be achieved, leading to high degree of mixing (decreased external mass transfer resistances) and to large reduction in size of the plant; and the removal of risk of clogging .
10 Read more
along the reactor where heat and mass transfer and chemical transformation processes take place. At the end of the heat treatment zone with a help of a heat exchanger, heat recovery of the dust-gas mixture is realized. After that the cooled mixture of dust and gas is separated into a solid target product SiO 2 and gaseous products of PPRH heat treatment.
There are mainly two excitation mechanisms for flow-induced vibration of thermowell in reactor coolant pipe under the cross flow: turbulence excitation and vortex shedding. The natural frequencies of the G1and G1 1/4 thermowell, and also the vortex shedding frequencies are calculated respectively in this paper. The vortex shedding lock-in is analyzed to the two different size thermowells, and then the study on flow induced vibratory fatigue analyses of the thermowell is performed using a simplified engineering approach.
Cathode chamber was also made of the same dimension. It has also two valves, the two valves for the electrodes connection. Anode compartment (depth 40 cm) was placed at top. The reactor has a cap of four openings for pH, gas collection, air inlet and temperature respectively. Other one is stand by to check the energy production of electrode at different distance. The effluent outlet is at the cathode chamber. Aeration is provided from the top of the reactor to the cathode chamber.
Reactor modelling that takes into account non-ideality at the design stage requires theoretical understanding of all the factors and phenomena that contribute to the reaction. The convection and diffusion effects of reacting and product species are computationally very intensive. Ideal reactor models make use of only macro mass conservation principles and some simplifying assumptions to arrive at equations called performance equations. Therefore though mixing contributes to the reaction, it does not play any role in the performance equations. The validity of assumptions to the real reactors plays an important role in the accuracy of performance prediction of the reactors using these equations. The simplest way of quantifying mixing adequate enough to incorporate kinetics in the evaluation of reactor is conventionally carried by using Residence Time Distribution (RTD) studies .