Reactors - Science topic

Hello everyone,

There are some problems in the operation of the alkylation unit that require a controlled shutdown of the unit, i.e. acid cleaning by circulating isobutane. When the aforementioned procedure was performed, the acid was not pushed up from the contactor to the settler. Why is this happening?

Thanks in advance,

Tihomir Kovacevic

I am currently working on my final year project titled "Design and Computational Study of a Radial Flow Reactor for Ammonia Synthesis." I have modeled the reactor in ANSYS Fluent (v2020) using a multiphase Eulerian model with iron catalyst as the solid phase and a gas mixture of N₂, H₂, NH₃, CH₄, and Ar.

I have written a UDF using DEFINE_VR_RATE to implement the detailed thermodynamics and kinetics for ammonia formation. The UDF compiles successfully, but when I run the simulation:

Here’s a quick summary of my setup:

If anyone has faced a similar issue or can suggest what to check or fix, I would be very grateful. I am sharing the UDF code too.

Thank you in advance!

We are feeding argon in a dielectric barrier discharge (DBD) reactor subjected to nanopulses with the parameters indicated in the attached figure. Is it possible to conclusively determine if there is plasma generation in the reactor by just looking at the V and I data produced by the oscilloscope? If not, what else would be required to confirm this?

Has climate change affected the formation of sulfate through the oxidation of copper SO2 by NO2 at aerosol levels? If so, in which regions? Is there a way to prevent it? What are the effects of humans and greenhouse gases?

Severe urban air pollution in China is driven by a synergistic conversion of SO2, NOx, and NH3 into fine particulate matter (PM2.5). Field studies indicated NO2 as an important oxidizer to SO2 in polluted atmospheres with low photochemical reactivity, but this rapid reaction cannot be explained by the aqueous reactive nitrogen chemistry in acidic urban aerosols. Here, using an aerosol optical tweezer and Raman spectroscopy, we show that the multiphase SO2 oxidation by NO2 is accelerated for twoorder-of-magnitude by a copper catalyst. This reaction occurs on aerosol surfaces, is independent of pH between 3 and 5, and produces sulfate by a rate of up to 10 µg m-3 air hr-1 when reactive copper reaches a millimolar concentration in aerosol water – typical of severe haze events in North China Plain. Since copper and NO2 are companion emitters in air pollution, they can act synergistically in converting SO2 into sulfate in China’s haze.Air pollution is a persistent problem in developing countries, such as China and other emerging economies experiencing rapid industrialization1–3 . Among the pollutants, the principal culprit is fine particulate matter (PM2.5), the airborne particles that can penetrate into human lungs, leading to premature deathsfrom cardiovascular and respiratory diseases and lung cancer4,5 . To mitigate PM2.5 and its public health impacts, the Chinese government renewed its air-quality policies in 2021, aiming for a 10% reduction of urban PM2.5 concentration by 20256 . Achieving this objective requires a clear understanding of the atmospheric chemistry producing PM2.5 in urban haze. China’s haze differs from London fog or Los Angeles smog in several ways. First, gas pollutants coexist at high concentrations3,7–9 , including SO2, NOx (NO and NO2), and NH3, emitted from industry, traffic, and agriculture10–12. These gases convert synergistically into PM2.5 through atmospheric multiphase reactions3,7–9 . Second, the multiphase reactions occur rapidly, much faster than what aqueous chemistry predicts8,13–15. Such rapid kinetics may result from many factors, including enhanced chemical reactivities at the air-water interface14,16,17, the catalytic effects of transition metal ions (TMI)13,18, or the salt effects in the oversaturated aerosol water15,19 – or all these factors acting simultaneously. Recognizing these characteristics, scientists coined the term haze chemistry to describe how PM2.5 is formed during the severe urban air pollution in China3,7–9,20. A decade-long debate in haze chemistry research concerns whether NO2 can effectively oxidize SO2 into sulfate, thereby contributing to PM2.5 formation. Why is NO2 considered an oxidizer of SO2? First, this redox reaction can occur in the atmospheric environments; NO2 can oxidize SO2 on the surfaces of primary particles (i.e., soot21 and dust9 ) and, more prevalently, in aerosol water7,22–24:2NO2 aq ð Þ þ HSO 3 aq ð Þ þ H2O ! Hþ ð Þ aq þ 2HONOð Þ aq þ SO2 4 aq ð Þ

Reaction Additionally, NO2 is abundant in the urban haze, especially when photochemical oxidizers such as O3, H2O2, and OH are inhibited in the polluted troposphere dimmed by haze8 or at night25. Field campaigns in China8,26,27 showed that sulfate and NO2 concentrations are positively correlated. A Beijing campaign25 found that the HONO produced by Reaction 1 can even further oxidize SO2. An air-quality model8 predicted that, at pH 5.8, the reaction between HSO 3 and NO2 (hereafter, the HSO 3 /NO2 reaction, and so forth) would produce sulfate by a rate of 10 µg m−3 air hr−1 . A laboratory study14 found that, at pH 6, a SO2 3 /NO2 reaction would produce sulfate by 90 µg m−3 air hr−1 .These studies suggested that sulfate PM2.5 in China’s haze was produced mainly through the NO2 reaction pathway. Yet equally compelling evidence indicates that NO2 contributed to SO2 oxidation negligibly. Although Reaction 1 can occur in the aqueous phase, it is unlikely to occur through a direct electron transfer, because the redox potentials between aqueous HSO 3 and NO2 are close28,29. The reaction instead occurs through the formation of [NO2-SO3] 2- adducts, which decompose to SO 3 radicals slowly28. This kinetic constraint rules out a rapid sulfate formation through Reaction 1. Additionally, the average pH of urban aerosols in China30 is approximately 4, which is more acidic than what previous studies have assumed8 . At acidic conditions, SO2 has limited solubility, leaving too few S(IV) ions (HSO 3 and SO2 3 ) to facilitate a rapid sulfate formation13,31. At pH 4, the sulfate formation rate via HSO 3 /NO2 8 and SO2 3 /NO2 14 reactions are respectively 0.04 and 0.15 µg m−3 air hr−1 . Recent air-quality models13,32 showed that the HSO 3 /NO2 reaction contributed approximately 0.1% of sulfate13; the SO2 3 /NO2 reaction, approximately 0.4%32. A source apportion study31 showed that the NO2 reaction pathway contributed at most 1% of sulfate in China haze. A recent globalscale study33 found that the NO2 reaction pathway is unimportant unless aerosol pH is above 5, a condition rarely met worldwide. These disagreements8,25–30,33 indicate a knowledge gap regarding how sulfate is produced in urban air pollution. Why does it matter whether NO2 contributes to sulfate formation? If so, then both SO2 and NO2 would be sulfate precursors, and effective abatement would require closer coordination between the industry and transportation sectors3,7–11. Bridging this knowledge gap requires us to answer the following question: Can the multiphase SO2 oxidation by NO2 occur rapidly at acidic conditions? Here, we show that NO2 can oxidize SO2 into sulfate rapidly at acidic conditions when the reaction is catalyzed by copper (hereafter, Cu). Cu, albeit a transition metal, is a weak catalystfor S(IV) oxidation by O2 34. But Cu is a strong catalyst for NO2 reduction by S(IV) in flue gas de-nitrification35,36. Additionally, Cu is ubiquitous in urban air pollution37. A field campaign38 reported that Cu elements were on the orders of hundreds of ng m−3 air during the air pollution in North China Plain (NCP). In Beijing, Cu mainly originates from traffic emissions, i.e., brake and tire wear39; in the broader NCP region, Cu mainly originates from coal combustions39. On the other hand, NO2 originates from both industrial and traffic emissions11,12, and its concentration can reach 40-to-80 ppb during heavy air pollution in NCP8 . In other words, Cu and NO2 are companion emitters, and they may synergistically convert SO2 into sulfate during urban haze. Furthermore, we show that the kinetics of the ternary Cu/SO2/NO2 reaction depends more sensitively on NO2 concentration, rather than on SO2 concentration. This may explain why, over the past decade, a substantial decrease in SO2 emission has not led to a proportional decrease in sulfate concentration in China. Results Method summary We studied the Cu-catalyzed reaction with Raman micro-spectrometry (hereafter, micro-Raman) and an aerosol optical tweezer (hereafter, AOT). The micro-Raman experiments provided information on the reaction mechanism, including the reaction products, the catalytic effect of Cu(II) ions, and kinetic dependence on droplet size (radius 5–30 µm) and acidity (pH 3–5). The AOT experiments provided kinetic data for the reactions in levitated droplets, under conditions closely mimicking urban air pollutions, such as droplet solute ((NH4)2SO4), acidity (pH 4), relative humidity (RH 60%), and reactant gases mixing ratio (SO2, 5–200 ppb; NO2, 50–500 ppb), and reaction time (hours). We designed these experiments based on literature values of aerosol pH13,30, gas concentrations8 , and RH conditions14. Specifically, the ranges of these parameters encompass their average values during severe pollution events in Beijing (i.e., pH 4, SO2 40 ppb, NO2 66 ppb). Refer to the Methods section for details. Copper-catalyzed SO2 oxidation by NO2 Figure 1A shows the Raman spectra of microdroplets, which served as reactors for the oxidation of SO2 (500 ppb) by NO2 (500 ppb). Droplet pH was buffered at approximately 4 with 400 ppb NH3 40. Ambient RH was approximately 80%. The left panel represents the reaction catalyzed by Cu(II) ions in the microdroplet seeded with a mixture of NH4Cl/HCl/CuCl2 (1:0.005:0.001). Here, the Raman spectrum exhibits a peak around 980 cm−1 , indicating SO2 4 formation (See Figure S1 for the full spectrum). This catalyzed reaction produced approximately 0.4 M sulfate in 240 min. Contrastingly, the right panel represents the uncatalyzed reaction in the microdroplet seeded with NH4Cl/HCl (1:0.005). This uncatalyzed reaction was too slow to be measured with the micro-Raman. In Figure S2, the AOT data shows that the reaction catalyzed by 0.1% Cu-in-solute was faster than the uncatalyzed reaction by two orders of magnitude. In both cases, the reaction did not produce NO 3 , which would exhibit a Raman peak at 1050 cm−3 . In other words, NO2 served only as an oxidizer of SO2 and did not undergo disproportionation at our experimental conditions. Figure S3 shows another control experiment, where NO2 was not applied, and no sulfate was produced within 240 min. Figure 1B–D show the kinetic dependence on droplet size and acidity. These experiments were conducted in NH4Cl/HCl/CuCl2 droplets (1:0.005:0.001), with a radius (hereafter, a) between 5 and 30 µm. Other conditions were 500 ppb SO2, 500 ppb NO2, 40-to-4000 ppb NH3, and 80% RH. Figure 1B shows that the reaction is faster in smaller droplets. Specifically, the SO2 4 formation rate, d SO2 4=dt, (unit: M s−1 ) is inversely proportional to droplet radius, a (See the dotted line in Fig.1C). This relationship indicates that the reaction rate is proportional to the droplet surface-area-to-volume ratio, such as A=V: Hereafter, we will normalize kinetic data as below:Droplet ambient conditions. The aerosolized droplets, led by an N2 flow, were then delivered to the optical trap inside the sample cell of the AOT system. This sampling process was considered successful when one of the droplets was captured by the optical trap. At this stage, the composition of the droplet is highly sensitive to the ambient gas phase, which should be maintained at stable conditions throughout the measurement. Specifically, the relative humidity (RH, 60 ± 1%) in the cell was controlled by mixing dry and humidified N2 gases. The RH was monitored with a hygrometer (CENTER-313, Qunte Technology Co., LTD). The temperature was maintained at room temperature (298 K) Reactant gases flowed through the sample cell with a prescribed mixing ratio. When investigating the Cu-catalyzed reaction, we applied the reaction gases per the following arrangements: SO2 was at 5, 10, 15, 25, 40, 50, 75, 100, 150, or 200 ppb; NO2 was at 50, 100, 250, or 500 ppb; NH3 was at 50, 100, 200, 400, or 800 ppb to buffer the (NH4)2SO4/NH4HSO4 droplets at pH 2.8, 3.1, 3.4, 3.7, or 4.0, respectively. When investigating the uncatalyzed reaction, we applied the gases per the following arrangements: SO2was at 0.1, 0.25, 0.5, 0.8, 1.0, 1.5, 2.0, 3.0, 5.0, 7.5, 10.0, or 20.0 ppm; NO2 was at 10 ppm; NH3 was at 0.8 or 8.0 ppm to buffer the droplets at pH 4.0 or 5.0 conditions, respectively. The detailed experimental conditions for the AOT study can be found in Table S7. Droplet pH was calculated with E-AIM40. Raman spectral data collection and analyzes. The backscattered Raman signal was collected with a time resolution of one second. During the reaction, the SO2 was continuously converted into SO2 4 , causing a continuous increase in droplet radius, a. Such droplet growth, albeit slight in magnitude, can be precisely determined by observing the redshift of the whispering gallery mode (WGM) in the stimulated Raman spectra. At each time step, t, we inverted the WGM wavelength λ to droplet size a, by using the Mie-scattering calculation algorithm provided in ref. 47. Next, the increase in droplet volume dV, during a time interval dt, can be quantified as: dV ¼ 4πa2 t atþdt a EquationS1Þ This increase in volume was contributed by the (NH4)2SO4 produced by the reaction, and the corresponding increase in the mole of (NH4)2SO4 is therefore: dn ¼ ðNH4Þ2SO4 dV ðEquationS2Þ Here, ðNH4Þ2SO4 is the molar concentration at an approximately 60% RH condition, calculated with E-AIM40. In summary, the reaction rate can be calculated from droplet growth rate per the following relationships: dn dt mols2 0da dt × L 1015μm3 ðEquationS3Þ and R mols1 μm1L 1015μm3 ðEquationS4Þ Here, a0 is the initial radius of droplets (unit, µm). The droplet growth rate da=dt (unit, µm s−1 ) was determined by linearly fitting the aðtÞ dataset. It is worth noting that Eqs. S1, S3, and S4 hold true only when the value of at a0 is much smaller than a0 (so that the curvature of the droplet surface can be ignored). In the AOT experiments, the at a0 did not exceed 50 nm, which is approximately 1% of the a0. For each experiment, the values of da=dt, the uncertainties (95% confidence interval values of the linear fitting), and the number of data points used in the fitting can be found in Table S7. Also, note that the treatment of Eqs. S3 and S4 requires that SO2 4 is the sole product remaining in the condensed phase. Such a condition has been confirmed in our Micro-Raman study (See Fig.S7). We also assumed that the productwas always (NH4)2SO4when NH3was in the ambient gases. Aqueous copper speciation model Visual MINTEQ. Following the method introduced in refs. 63,64, we estimated the chemical speciations of Cu(II) in the aqueous phase of Beijing PM2.5 by using Visual MINTEQ model version 3.1. The visual MINTEQ model, which was originally designed for chemical speciation analysis in natural aquatic systems, has also been successfully utilized for estimating metal speciation in aerosol water63,64. In other words, this model accounts for metal-organic complex formation and calculates the fraction of metals existing as organic complexes. The model input parameters included the aqueous concentrations of secondary inorganic matters (SO4 2−, NO3 −, and NH4 +), dicarboxylic acids (oxalate, malonate, succinate, and glutarate), and metal ions (Na+, K+, Mg2+, Ca2+, Al3+, Mn2+, As3+, Cr2+, Cu2+, Ni2+, Pb2+, Sb3+, Se4+, Zn2+, Fe2+, and Fe3+), as well as aqueous pH (fixed at 4) and temperature (fixed at 25 °C). These PM2.5 composition data were acquired from field campaigns conducted in Beijing38,66,67. Details of the composition data can be found in Table S4. Following that recommended in ref. 64, we adopted the specific interaction theory (SIT) for the ionic strength correction of the stability constants of the metal complexes. SIT correction was preferred because it is more appropriate for the high ionic strength condition (>1 M) of urban aerosols64. Sulfate, nitrate, and ammonium. We estimated the aqueous concentrations of inorganic matters with the E-AIM model40 according to the hygroscopicity of a SO4 2−/NO3 −/NH4 + mixture at a molar ratio of 1:1.5:3.5 and at an ambient RH of 80%. The molar ratio of the mixture was determined according to the mass fractions of SO4 2− (19.2%), NO3 − (18.5%), and NH4 + (12.6%) in Beijing PM2.5 at heavily polluted conditions67.

Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.

I have ionic liquid and H2, CO2 gas, catalysts. I want to do the hydrogenation reaction in a high pressure reactor but I dont know how to feed the reactants then start the experiments.

Thank you so much!

Hi everybody,

I am currently working on simulating a reactor that involves numerous known and unknown reactions. To tackle this, I am considering the use of the Lumped Kinetic Model in Aspen HYSYS. However, I don't know how I can approach this simulation in Aspen HYSYS.

Has anyone successfully implemented this model for similar simulations? I would greatly appreciate any insights or solutions you could share regarding this issue.

Best regards, Sadra Mahmoudi

Please share a video link if available

In Some kinetic modeling articles, a reaction network has been proposed , where in some components with similar properties ( but different molecular formula and structure), put in a hypothetical component that is named lumped group. for example:

C : C2H4 ,C4H8 ,C3H6.

M : MeOH , DME.

C + M >>>> C , (reaction rate constant and activation energy is specified)

………………..

How can apply such kinetic and reaction network in aspen plus for simulation the reactor and related plant?

Hello everyone,

I want to use a Fortran Subroutine for biomass gasification to implement improved kinetics for tar formation (kinetics from Abdelouahed.2012) using a RPLUG reactor. While the subroutines for conventional components work well, I am having trouble accessing and changing properties of the biomass (as a non-conventional component) in the subroutine. I tried using the stream structure from the "Aspen Plus User Models"-help, which should result in one array for all substreams (conventional, CISOLID, and non-conventional) listing each component flows and physical properties of each substream one after another. But after all data of the conventional substream, there are no more values in the array where the data of CISOLD and non-conventional substreams should be. So, how can I access the values? Do I need to include an additional command? It also does not seem to be a matrix structure (column for each substream).

Thanks a lot for your help!

Is doping NMC with Al through solid-state methods more effective than co-precipitation, as a coating layer generates on the particles? Is it necessary to have a spherical morphology with small primary particles?

I have recently synthesized NMC811, although I have encountered some problems. I would appreciate it if you could guide me. Specifically, I want to know if the synthesis conditions are appropriate. I have attached the SEM results for your reference.

My synthesis conditions are as follows:

I am working on photocatalytic water splitting from a suspended catalyst. I can measure the total volume of gas evolved from the water displacement method. But by this method, I cannot store my gas evolved and it will be lost. And I have to do a gas chromatography analysis to measure its composition. If I measure the total volume of gas, I can't do a gas analysis on that gas. If I do gas analysis by storing it in a bag, I can't measure the total volume of gas and I can't attach the gas chromatography apparatus directly to the reactor because I do not have access to that directly, I have to send a sample somewhere else for analysis.

What can I do please help me in this regard as soon as possible.

I'm interested in the idea of consent-based siting as a strategy to build local democratic capacity while also solving collective action problems of locating controversial infrastructure that is needed for social well-being, decarbonization, and climate mitigation/adaptation.

Consent-based siting is presently being promoted by the US Department of Energy to locate one or more consolidated interim storage facilities for spent nuclear fuel from commercial reactors. Attached is a file that includes definitions of consent-based siting in DOE publications.

Some assumptions for the biogas production plant.

1. Feedstock flows from the sisal processing plant to the AD system of a biogas plant through gravity,

2. The AD system operates on a continuous stirred tank reactor,

3. Digestate flows through a controlled system of pipes to the open lagoon, and

4. The purified biogas is burnt to generate electricity at the CHP unit.

Hello! I just wonder if there a free software to draw a graphical abstract where I want to draw a simple picture of a reactor and few chemical reactions

Thanks!

Our lab needs an upgrade to allow for a faster sample throughput, but also need to try to keep the price down. Does anyone know if there are refurbished microwave reactors? We're looking for something along the lines of a Biotage Initiator.

We have a closed system with reactor connected to that of a gas chromotography. From out catalyst, we expect only hydrogen peak, but there is oxygen and nitrogen peak detected also. The main issue is the area of the peaks keep increasing drastically for each run. We do not inject any gas manually, so that we can reduce the manual errors, but still we are facing issue with understanding from where these two peaks are coming from. If there is any leakage, we should be seeing change in the pressure inside the reactor, but there also it is not increasing drastically.

We have a closed system with reactor connected to that of a gas chromotography. From out catalyst, we expect only hydrogen peak, but there is oxygen and nitrogen peak detected also. The main issue is the area of the peaks keep increasing drastically for each run. We do not inject any gas manually, so that we can reduce the manual errors, but still we are facing issue with understanding from where these two peaks are coming from. If there is any leakage, we should be seeing change in the pressure inside the reactor, but there also it is not increasing drastically.

I am looking for the information on comparing properties of CCl₃Br vs CBr₄ for in situ etching of InP in the MOVPE reactor. I would appreciate for any input on this problem.

The future of nuclear power depends upon several factors. One of these factors is the use of small module reactor (SMR) for electricity generation and for other non-electric applications. Several prototypes of SMR are under development in several countries, but only four of them at this moment are under construction in three countries. This type of nuclear power reactor will receive the approval of the public opinion of those countries thinking to expand or to introduce nuclear energy for electricity generation in the coming years and will allow the construction of this type of reactor in their countries? Which are these countries?

I would like to measure the light intensity delivered to my solution inside the double-walled glass reactor, as shown in the attached picture. I am using a Thorlabs PM100A power meter, which measures light power in watts. The desired unit for light intensity is watts per square meter, but I am unsure how to measure this due to the curved geometry and the double-walled structure of the reactor. How can I accurately determine the light intensity in such a setup?

I have a question for those of you who frequently use microwave reactors. I recently acquired a rather older one and want to use it to accelerate the long reactions, which typically take 100 - 150 hours, but due to the microwaves, the reaction time may be reduced twice or more. As for the magnetron what should be better - is to use it on low power all the time (the reaction mix is maintained at optimum temperature at only 150W) or the reactor health should heat at maximum power and then have some time to cool down.

I wonder what you think. Do you have any other suggestions for reasonable microwave reactor use?

For example, let's say if I design a conversion reactor and give inlet temperature,pressure,composition and reaction kinetics then Hysys will show me the outlet conditions. It doesn't,however,show the process or how it got the results i.e calculations.

It will be very helpful if you can answer this.

Thanks in advance.

A typical reforming section in a large-scale Haber-Bosch process (Figure 1) comprises two reactors. A mixture of methane (CH4) and steam (H2O) is fed into a primary reformer to produce syngas via steam reforming (SMR). The gas product is then fed into a secondary reformer where it is mixed with air before going through a second steam reforming process. The air introduced into the secondary reformer (ATR) provides not only a suitable amount of nitrogen for ammonia synthesis but also some oxygen to exothermally oxidize part of the feed stream, thus decreasing the energy requirements of the steam reforming section of this reformer.

An alternative reforming process is proposed in Figure 2. Unlike the conventional approach, the first reactor is used to catalytically oxidize the methane feedstock at low temperatures using a sub-stoichiometric amount of air (CPOX) and consuming 100% of the oxygen. In the secondary reformer, a steam reforming process is performed to increase the amount of H2 produced.

Based on thermodynamic grounds, these two processes are expected to produce the same reformate; however, the use of low-temperature catalytic partial oxidation in the first reformer may lead to smaller reactor sizes as well as the reduction of potential fire hazards as flammable mixtures will not be exposed to high temperatures.

Is there any other foreseeable advantage of the alternative reforming approach?

After the fukushima accident, passive thermal shutdown seals were introduced in the reactor coolant pumps in many NPPs of Westinghouse design, or similar.

Do you know what improvements were made to the reactor coolant pumps of VVERs to minimise the leakage rate in case of SBO?

I am preparing ammonia cracking catalyst. I dont have a thermal reactor to study ammonia decomposition and the efficiency of my catalyst. Can you suggest me any alternative study to understand how my catalyst would act in a decomposition process. That I can check in my lab

Hi, I have established a bioreactor parameters mammalian cell process with the following parameters:

Setpoint Deadband PID settings

1) pH- 7.0 0.1 1.0,5.0,1.0

2) DO- 60% 1 1.0,1.0,1.0

3) Stirer- 127 0

4) PO2 cascade with oxygen at (10ml/min)

5) pH cascade with base and (acid CO2 at 10ml/min)

The issue here is still the oxygen doesn't stop at the given setpoint and reaches around 120-180 % DO.

what can I do to maintain the DO to the specific setpoint. The total volume of reactor is 250ml and WV is 100ml.

The other issue here is the stirrer speed at what rpm I should be keeping it. Can we calculate the rpm of the stirrer according to the volume of the working volume of the reactor. Tip speed was calculated as- 0.0376m/s.

please let me know if more information are needed.

I need a PET + Solvent mixture to feed it to a fixed bed reactor for steam reforming.

I am seeking your advice regarding the use of a 50L photosynthesis reactor for wastewater treatment. I intend to supply pure CO2 but am uncertain about the appropriate CO2 flow rate (L/min) for the reactor. How to determine this value based on reactor volume?

If you have any references or recommendations, please provide the titles. Your guidance would be greatly appreciated!

Thank you very much!

Can someone explain the difference between a monowave and a microwave reactor? I understood that a monowave reactor is a type of microwave reactor.

In the link below, it says: Monowave 50 performs typical lab experiments at a speed comparable to microwave synthesis reactors, yielding results of equal quality (i.e. same yields and product purities) for a fraction of the price of a microwave reactor.

So what is the fundamental difference?

A methanol production process combines tri-reforming of methane (TRM) with water electrolysis to utilize CO₂. The TRM reactor uses a Ni/Al₂O₃ catalyst, and the methanol synthesis reactor uses a Cu/ZnO/Al₂O₃ catalyst. The goal is to achieve a methanol production rate of 2095 tons per day, with a gas hourly space velocity (GHSV) of 3000 h⁻¹ in the TRM reactor. Calculating the required catalyst quantities involves considering the reaction conditions and catalyst efficiencies.

I am trying to do small scall experiments in which I mix 50 mL of liquid with a powder to leach the powder. The liquid is concentrated formic acid at 95 degrees C. Right after the experiment is over I need to be able to get everything out of the reactor, including a new powder that forms, very quickly before the liquid and powder cool. I can't use water to rinse the solids out of the reactor because I don't want to dissolve them and I would prefer not to rinse with anything at all. The question is what kind of flask should I use and how do I get all the solid out quickly that remains on the walls after I dump all the liquid. I was thinking of an 100 mL Erlenmeyer flask and a flexible Teflon scrapper/spatula but I can't find a scrapper that small and the small ones that I do find I don't think they are flexible. Any thoughts?

In uranium-hydrogen-zirconium materials, hydrogen is redistributed according to temperature distribution, which may affect reactor reactivity. Does the reactivity of the reactor increase or decrease after the redistribution of hydrogen, and is the change in reactivity negligible?

Just wondering if anyone has any experience in setting up a Getinge mini bioreactor? More specifically, autoclaving the reactor, the gel pH sensor, and the dO2 sensor.

I am having trouble understanding how to use the pH probe and "pressurize" in the autoclave before first use. The pH probe has a lifecycle of 10-15 autoclaves. Would I have to bathe the probe in ethanol as a method of sterilizing the probe between cell cultures?

Any advice is welcomed! Thanks so much in advance!

Can someone help me on response surface optimisation by state-ease design expert software for compositional responses [% composition of responses]

I want to decompose a particular type of biomass in a reactor under controlled conditions of temperature and residence time. I want to optimise the operating conditions of the reactor by varying the temperature from 200 to 500 degrees Celsius and residence time from 5 to 50 minutes. The responses are four decomposition parameters of biomass, which must sum up to 100%. Let say when heating the biomass at a certain temperature and residence time, the biomass decomposes to four products [X%, Y%, Z%, M%], sum of which should be 100%. So I want to optimise one of the product, let say X%.

I did the response surface methodology [two factors] and conducted the required number of experiments.

In the analysis, I can see the expected behaviour of responses with the variation of the two factors. But the problem comes on the optimisation side, the optimum conditions suggested by the software gives the responses that exceed 100% , which is not feasible.

Can you please comment on it, like what design I was supposed to use or what is the optimum responses suggested tells about.

Thank you

explain the calculations

I would like to know examples of reactors models/anaerobic digesters for biomethane production from highly lignocellulosic materials at pilot or industrial plant level.

I appreciate your collaboration.

Thanks in advance

For the investigation of the start-up of an alternating anaerobic-anoxic reactor, I would like compute the potential biomass decay for aerobic organisms (specifically autotrophic ammonia oxidizers (AOB, AOA)) in my inoculum. For this purpose, I am going to apply specific decay rates of AOB and AOA, but I am lacking knowledge about the autotrophic cell mass in my inoculum.

Can anybody provide average values or a ranges of the share of autotrophs in the MLVSS of typical conventional activated sludge systems?

Thank You already for advice!

I utilize a photosynthesis reactor for wastewater treatment. Within the reactor, I collect biomass and aim to establish its molecular equation of biomass, such as CxHyNzPtKi.... I would greatly appreciate any advice, techniques, or relevant papers you could provide on this matter.

Hello Everyone,

I am facing a challenge of determining reliable kinetics. I know ICTAC recommended multiple heating to perform to perform reliable results.

However, I am conducting single heating rate with various oxygen concentration. I was able to use THINKS to model non-linear fitting ( Especial thank to Dr Nikita) and got some results which close to literature. However, this is based on single heating rate which against the reccomndation ICTAC.

I can't do more experiments because I ran out of my sample and I am not able to get more.

I am using these kinetics to model a reactor in CFD. I want to see is their ideas or opinions that I can do to make my kinetics reliable. Or at least is this recommendation is solid one that cannot waived if I decided to publish a paper.

Maybe you can give me some recommendation on this matter. I have two reactors, one of them contains a solution of 90% water type 2 and 10% banana peels. On the other hand in reactor two there is a solution of 90% swine wastewater and 10% banana peels. The question is, to determine nitrogen in both samples should I do it in the liquid (previous filtration) or should I do it in the suspended solids contained in both liquids?

Where to determine nitrogen?

hello Everyone,

if I want to study, coal combustion in different atmospheres for example in O2/N2 and O2/CO2. I obtain the kinetics of both atmospheres using Hetrogenous models. ( Shrinking core model ) and Random pore model.

I was wondering if it’s possible in CFD to study particle profile. Does the heat transfer affect in CFD will calculated based on the Gas composition input or I should add something in UDF file.

FYI, the reaction models are based on conversion so I am not really sure how CFD will identify the differences in Atmospheres.

further, I wish If I found a sample UDF file that been used for Hetrogensous models.

Ahmad

Hlo I am trying to get kinetics of methanol to dimethyl ether kinetics on hzsm-5 si/al = 40 catalysts at 160 deg c I was unable to reach zeroth order kinetic regime. I doubt that the reaction will become mass transfer control before it reaches zero order kinetics. Please let me know what should be the partial pressure of methanol when the reaction reaches zero order . I am also using a fixed bed catalytic reactors where i change the flow rate of methanol to change the partial pressure and i am also injecting nitrogen along with the methanol where i am changing the methanol flow rate. Please let me know is this an ideal practice for getting kinetics. Please let me know

Thank you.

Vignesh

Hi, I am using FLUENT 19.2 to simulate a packed bed reactor of simple rectangular cross section. Solid inside the reactor (CaO) is porous and gas (Steam) enter the reactor from bottom. Product of the reaction is calcium hydroxide(which is also solid). The reaction is exothermic and the heat generated is transferred to fluid (HTF) flowing outside along the walls of the bed.

I need to know if it is possible to simulate this reaction using Ansys Fluent. If yes then which models/procedure should be used. Is there any tutorial available for this kind of reaction in fluent? Thanks

I simulate a reactor in MCNP. However I want to know the spectrum (energy) and flux in a specific surface (or cell) away from the nucleus (source). I thought using F2 tally, but I do not want the normilize value. I want the measured integral value. How do I do this?

Hello scientists

I am PhD student in united states workin in acid sites characterization in zeolites. I am using methanol as a probe molecule to investigate the acid sites in zeolites. I am using fix bed catalyst reactor along with k type thermocouple connected to a temperature programmer and outlet of the reactor is connected to the gc system. I am facing the issue of reproducibility in my reaction I am getting 30% increment and decrement in conversion each an every time I try to run the reaction with the same catalyst mass. Please suggest me what could be the possible cause for this problem.

I am trying to calculate power density in the reactor core using mesh tally. I have used the FM card & got the results. Instead of explicitly setting material number on FM card (61, in my case), I want MCNP to track the material itself based upon the mesh being sampled! Is that possible somehow?

snippet of my input file is, C TALLY FOR POWER DENSITY FMESH14:N GEOM=CYL      ORIGIN=0 0 -351.818           IMESH=6.5 13 19 25 39 50 60 70.5 83.5 90           IINTS=  1  1  1  1  1  1  1    1    1  1           JMESH=7.5 25.5 43.5 61.5 79.5 97.5 115.5 133.5 151.5 169.5 187.5               JINTS=  1    1    1    1    1    1     1     1     1     1     1           KMESH=1           KINTS=1           AXS=0 0 1               VEC=1 0 0 FM14 (1 61 -6)

Dear Friends,

I am looking for a faculty or Engineers or others who are interested in working on CFD of multiphase flow in chemical engineering reactors for collaboration research. Please contact me on Facebook messenger or text and call on +9647713171293.

Associate Prof Haidar Taofeeq

We have 1 gm SrSO4 of density 3.7 g/cc. It has 0.174 gm S32 in it. It is irradiated in 1.6E11 flux in KAMINI reactor. What will be the yield of P32 in Ci/g?

Reaction: S32(n,p)P32.

This is the statement of the problem.

Now we have the neutron flux spectrum of the irradiation location.

Our doubt is how to incorporate FM4 card to calculate the reaction rate i.e N*Sigma*Phi.

FM4 card uses a contant C. what should be this C for our calculation?

Hi 👋

I hope this message finds you well. I am currently collecting data on the design of a reactor system operating at 200 bar pressure and 300 degrees Celsius temperature, with a reactor volume of 100 liters. Specifically, I am looking for recommendations on the appropriate sealing solution for the mixer in this system.

Considering the challenging conditions, I am curious to know if anyone has experience with or can recommend a specific brand or model of seals that would be suitable for this application. I would appreciate any insights, suggestions, or firsthand experiences you may have in this area.

Thank you in advance for your time and expertise.

Best regards, 🙏

Respected sir/madam,

Let me introduce myself as Anjali, a research scholar from India who just started PhD work in the last 2 months. I have been given my tentative research title as "Photolysis induced Hydrogen generation from water by Graphitic Carbon Nitride and related hybrid" . During literature review for the above topic I have gone through some related papers and found interesting. However as a beginner i have some basic queries before starting my work which are the following;

1. Hydrogen generation is possible from pure water or some suitable activator has to be added and why. I have found article where Na2S and NaSO3 is added to water before starting the experiment.

2. Is it necessary to immerse the light source into the water or light can be sent from above also (as in our reactor we have the reactor vessel with a large capacity around 1L and thus if we want to place the light within the water it will require a very high quantity of material).

3. Our reactor has 3 outlets and I have planned to externally seal two of them and the third outlet will be released within the water taken in a beaker through a suitable connector. Can I expect a bubble formation in the beaker even when the quantity of the evolved gas is very less.

It will be very helpful for me if you kindly find a precious time to answer my above-mentioned queries at the earliest so that I can start my experimental work accordingly.

Waiting for your kind answer.

Humble Regards

Thank you

Anjali

I am working on the design of the anaerobic baffled reactor for the treatment of dairy wastewater. I need assistance to determine the HRT and OLR for the reactor.

I have this error message on my Aspen plus when simulating the reactor (REqul) simulation.

"WARNING WHILE CHECKING INPUT SPECIFICATIONS

BLOCK NAME: B1 MODEL NAME: REQUIL

PHYSICAL PROPERTY PARAMETER DGSFRM IS MISSING

FOR THE FOLLOWING COMPONENTS:

N2H8SO4

ABSENCE OF THIS PARAMETER WILL RESULT IN

INCORRECT CHEMICAL EQUILIBRIUM CALCULATIONS."

Can anyone help how to fix the problem, please?

I want to start the discussion.

Does the reaction occur more dominantly on the reactor wall due to the influence of the heating surface in the pyrolysis process without a catalyst?

Hello everyone,

I am trying to condense pure ethylene oxide in a reactor at 0 ºC containing an organic solvent. We have a bottle of pure ethylene oxide connected to a stainless steel reactor, but the ethylene oxide remains in the gaseous phase.

Does anyone have experience working with ethylene oxide in its liquid form?

Thanks in advance.

Please click the for further information. I just want what the community thinks/feedback.

Thanks.

Hello all dear

If you have any references, can you share me?

Thanks in advance

hello

I interface with an aspen plus error which I don't know why.

I chose a RGibbs reactor with inlet and outlet streams and enter 3 reactions.

just it but when I run this program, it gives me an error "encountered while processing input specifications. see the control panel?" I did the design from a book and that book was able to run from its design.

what should I do?

Panel Discussion, October 26, 2023--- 12 pm PST 7pm UTC

Free Registration: https://conta.cc/3RZD2uq

Hello all dear.

We have a CTRS reactor whose its temperature is measured by a transmitter and controlled by a PID controller.

As a result of entering a solvent into the reactor, its temperature fluctuates.

My question is, how can this temperature fluctuation be eliminated?

A dense Spirulina culture was split in half and used to start two identical photobioreactors. After one day of growth, both reactors were harvested (approx half the biomass removed). After two days of growth, one reactor has flocculated (left-hand sample in the photograph) and the other has not (right-hand sample in the photograph). What factor or combination of factors do you think could have caused this auto-flocculation?

The two reactors were identical in size and shape and both cultures had the same nutrient medium and agitation. The only differences we can think of were: the culture that flocculated had slightly higher light intensity, slightly higher temperature and part of the culture was passed through a pump.

As GHSV, gas hourly space velocity is basically the ratio of volumes of feed gas at STP/hr to the volume of the reactor or catalyst. Can we report the GHSV based on mL*gr-1cat h−1 because it would be difficult to calculate the exact volume of a catalyst powder?

Thank you.

At a medium-flux continuous neutron source (research reactor), and experimentally, the famous method that I know and already performed for determining "thermal neutron capture x-section and resonance integral" for some isotopes is:

>> Material irradiation and analysis using the Neutron Activation Analysis (NAA) technique at specific and known experimental conditions.

What else, please? what about possibilities using horizontal neutron beams, if any? Keeping in mind all types of neutron x-sections: Total & Absorption & Scattering.

I would like to simulate a process, I know T,p, and the selectivity. Can I calculate the reagent conversion in Aspen Plus?

In that case, what kind of reactor should I use?

Thank you in advance.

If you know any reference about that, please say me

If you know any reference, please say me

Hello all dear

Question data:

Solvent enthalpy, amount of condensate in terms of time, temperature before and after solvent evaporation

Hello all dear

The temperature of a reactor is 105 degrees Celsius and some solvent enters it. The temperature of the reactor decreases (98) and some solvent evaporates.

In this system, water vapor is also entered to control the temperature.

How can this system be cooled so that the solvent, which is valuable for us, condenses and returns to the liquid phase, but the water vapor does not condense and exits in the gas phase?

The temperature of the vessel before being filled with solvent is 105 degrees, and after the solvent enters it, a certain amount evaporates and the temperature of the vessel decreases to 98.

Knowing the enthalpy of the solvent, how to calculate the volume of evaporated solvent?

currently I am modeling the membrane reactor. hydrogen (reaction product) as a permeated substance. when modeling a packed bed reactor I use:

D=(U*Dp)/(11*(1+(19.4*((Dp/(d1*2))^2))))

D= diffusion coefficient

U=velocity

DP=catalyst diameter

d1=reactor diameter (to membrane line)

to calculate the effective radial diffusion coefficient in packed bed (m2/s) and the results are in accordance with experimental.

but when modeling the membrane packed bed reactor, the simulation experienced an error.

Are there any suggestions regarding the diffusion coefficient equation for permeated substances that is more suitable for me to use?

Your answer will be greatly appreciated.

The vessel is a CSTR

I have a electrooxidation setup that have 6 anodes and 7 cathodes in alternate arrangement. The surface area of the plate is 1m2 and the applied current is 100A. How to measure the current density across the reactor? Does the surface area for each plate count? Or we can assume a constant cross sectional area throughout the reactor? kindly advise

Hello all dear

The temperature of the vessel before being filled with solvent is 105 degrees, and after the solvent enters it, a certain amount evaporates and the temperature of the vessel decreases to 98.

Knowing the enthalpy of the solvent, how to calculate the volume of evaporated solvent?

I am using water plastic bottle cap as a biocarrier in MBBR reactor. how could I measure the surface area or SSA(m2/m3) of the cap that has three holes on top?

thank you for contribution

To prepare lithium battery cathode precursor material by hydrothermal method, a certain amount of nickel, manganese and cobalt metal salt with precipitant was poured into the reactor, after the process, the amount of nickel in the precursor material was lower than the amount that entered the reactor , what is the reason?

Do bacteria reproduce in microbial fuel cell reactors while generating electricity? If yes, how fast and how soon are the reactors getting full, especially as applied to wastewater treatment.