Conversion Levels Research Articles

A comparative study of applying backscattering and transmission Raman spectroscopy to quantify solid-state form conversion in pharmaceutical tablets

Selecting appropriate Raman measurement and data processing method are of importance to enable effective quantification of solid form conversions upon processing or storage. Therefore, a comparative evaluation is presented herein on using backscattering and transmission Raman spectroscopy to quantify salt disproportionation in tablet matrices. The second part focuses on different spectra processing approaches and calibration models for quantifications. Finally, samples under different mechanical stresses were comprehensively analyzed using different Raman measurements. Much as transmission Raman spectrometry may provide accuracy on bulk measurements by having large sampling volume, it has the drawback of signal attenuation and may overlook process-induced phase transitions occurring on local regions of tablet surface. To overcome this limitation, backscattering Raman with deliberate subsampling can be used as an orthogonal method to probe the existence of low-level form conversion distributed over a tablet’s surface. In the present case, different levels of the form conversions were found at the edge and the center of tablets due to the uneven shear stress distribution invoked during tablet compression. In such a scenario, it would be beneficial to apply deliberate-focused backscattering and transmission Raman spectrometry together as complementary techniques to capture chemical information both locally and within the bulk of the tablet.

PALM OIL BIODIESEL: CHALLENGES, RISKS AND OPPORTUNITIES FOR REDUCING AND REPLACING THE NON-RENEWABLE FOSSIL FUEL DEPENDANCY - A REVIEW

Biodiesel is a renewable source of energy which is expected to play a signifi cant role for reducing andreplacing the existing non-renewable fossil fuels. Palm oil is one source of biodiesel feed stock which hasbeen used for many years and gave so many advantages such as high oil yield, cheap to produce and torefi ne, has similar characteristics with petroleum-derived diesel, and has lower emission. However, someissues, such as food stock security, land use changes, and biodiversity extinction, have arisen which needto be considered and solved wisely. Life cycle assessment (LCA) study shows a positive net energy and anet positive sequestration on GHG emission (up to some level of conversion from palm oil to biodiesel)which means biodiesel from palm oil has a high potential to replace fossil fuel and also an environmentalfriendly fuel.

Preliminary Evaluation of Automated Speech Recognition Apps for the Hearing Impaired and Deaf.

ObjectiveAutomated speech recognition (ASR) systems have become increasingly sophisticated, accurate, and deployable on many digital devices, including on a smartphone. This pilot study aims to examine the speech recognition performance of ASR apps using audiological speech tests. In addition, we compare ASR speech recognition performance to normal hearing and hearing impaired listeners and evaluate if standard clinical audiological tests are a meaningful and quick measure of the performance of ASR apps.MethodsFour apps have been tested on a smartphone, respectively AVA, Earfy, Live Transcribe, and Speechy. The Dutch audiological speech tests performed were speech audiometry in quiet (Dutch CNC-test), Digits-in-Noise (DIN)-test with steady-state speech-shaped noise, sentences in quiet and in averaged long-term speech-shaped spectrum noise (Plomp-test). For comparison, the app's ability to transcribe a spoken dialogue (Dutch and English) was tested.ResultsAll apps scored at least 50% phonemes correct on the Dutch CNC-test for a conversational speech intensity level (65 dB SPL) and achieved 90–100% phoneme recognition at higher intensity levels. On the DIN-test, AVA and Live Transcribe had the lowest (best) signal-to-noise ratio +8 dB. The lowest signal-to-noise measured with the Plomp-test was +8 to 9 dB for Earfy (Android) and Live Transcribe (Android). Overall, the word error rate for the dialogue in English (19–34%) was lower (better) than for the Dutch dialogue (25–66%).ConclusionThe performance of the apps was limited on audiological tests that provide little linguistic context or use low signal to noise levels. For Dutch audiological speech tests in quiet, ASR apps performed similarly to a person with a moderate hearing loss. In noise, the ASR apps performed more poorly than most profoundly deaf people using a hearing aid or cochlear implant. Adding new performance metrics including the semantic difference as a function of SNR and reverberation time could help to monitor and further improve ASR performance.

Compact ammonia reforming at low temperature using catalytic membrane reactors

Ammonia is a leading carrier for the storage and transport of renewable hydrogen, but its deployment requires scalable technologies for efficient decomposition and purification. In this work, we report on the efficient delivery of high purity hydrogen from ammonia decomposition using a catalytic membrane reactor (CMR). Improvements to the electroless plating process reduced the Pd membrane thickness by >35%, resulting in commensurate increases in hydrogen permeance without sacrificing selectivity. To increase throughput a commercial Ru/Al 2 O 3 catalyst was added to the lumen, and the CMR could process ammonia flowrates 10–50 times higher than an equivalent packed bed reactor while maintaining the same level of conversion. It is shown that the earth-abundant zeolite clinoptilolite could reduce ammonia impurities in the permeated H 2 to the levels required by PEM fuel cells (<25 ppb). Performance increased significantly across a >500-h durability test due to improvements in membrane permeability. The results show that CMRs are a viable technology for distributed production of hydrogen from ammonia. • Ultrasound-assisted plating enabled reduced thickness and defect density • CMR volumetric productivity >50 mol H 2 /m 3 *s and >500 h stability • CMR displays 10–20X higher throughput than equivalent PBR for NH 3 decomposition • Demonstrate ability to recycle, reuse CMR supports • Clinoptilolite adsorbent shown to reduce residual [NH 3 ] to <25 ppb

Time Metaphors in Film: Understanding the Representation of Time in Cinema

According to conceptual (cognitive) metaphor theory (CMT), there are two basic metaphorical models for conceptualising time in terms of space: the ego-moving model maps our movement through space onto our imagined movement through time, while the time-moving model represents time as an entity moving through spatial locations, the ego being just a passive observer. The aim of this article is to investigate how time is conceptualized in film where ego (character), movement, time and space also play basic roles. I compare the two linguistic models to Gilles Deleuze’s conceptualization of filmic time: the movement-image and the time-image. While the movement-image and the moving-ego metaphor directly map spatial structures onto the domain of time, the time-image and the moving-time metaphor correlate only in their basic structures and involve different levels of conceptual integrations and conversions. Due to film techniques such as a mobile camera, montage and image manipulation, the time-image seems to transcend the constraints of natural perception and maps onto mental rather than external space, thus giving rise to a new reverse metaphor where space acquires characteristics of the time domain.

Improving the performances of a simulated-moving-bed reactor for the synthesis of methyl acetate ester by using partial port-closing strategies

Simulated-moving-bed reactor (SMBR) is one of the trustworthy processes to achieve high levels of conversion, yield, and throughput for an equilibrium-limited reversible reaction. As one way of finding a practical method to significantly improve the performances of an SMBR, the applicability of a partial port-closing strategy and its potential impact on the SMBR performances were investigated for the first time in this study. To facilitate this work, the synthesis of methyl acetate (MeOAc) ester was employed as a model reaction system. There are two applicable modes for implementing the aforementioned strategy in the SMBR for MeOAc synthesis. The first one is a partial extract-closing (PEC) mode, in which an extract port (non-product port) remains closed during the time that MeOAc passes through two zones adjacent to the extract port. Such action occurs mostly during the beginning of each step. By contrast, the second one is a partial raffinate-closing (PRC) mode, in which a raffinate port (product port) remains closed during the time that unreacted and side-product components pass through two zones adjacent to the raffinate port, which happens mostly during the end of each step. A series of comprehensive optimizations for the considered SMBR revealed that both the PEC and PRC strategies were effective in making a significant improvement in reaction yield, throughput, and solvent usage. It was also found that the higher the required throughput, the more advantageous it was to use PEC rather than PRC mode. Finally, it was confirmed that the merit of PEC over PRC mode in the economic feasibility of the SMBR became greater as the target levels of reaction yield and throughput were set higher.

Bioenergy potential analysis of Brazil nut biomass residues through pyrolysis: Gas emission, kinetics, and thermodynamic parameters

The kinetics of the pyrolysis of Brazil nut residues (Bertholletia excelsa), in this case, shells (BNS) and husks (BNH), were investigated via a thermogravimetric analysis in an inert atmosphere. The Flynn–Wall–Ozawa, Kissinger-Akahira-Sunose, Starink and Vyazovkin isoconversional models were used to estimate kinetic and thermodynamic parameters. The mean activation energy values ranged from 135.59 to 138.51 kJ/mol for the shells and from 151.94 to 153.92 kJ/mol for the husks in the active pyrolysis region. High values of the pre-exponential factor (>108 s−1) indicated the presence of complex reactions for both samples, which was confirmed in the analysis of the reaction mechanism using the master-plot method, through the multiple types of behavior during the variation of the conversion levels. Thermodynamic parameters, such as the enthalpy change, Gibbs free energy change and entropy change, characterized a nonspontaneous endothermic process, with little energy required. TG-MS analyses revealed less harmful gas emission behavior for the environment compared to fossil fuels. The results of the study, with an emphasis on its satisfactory higher heating value (13.8 and 14.6 MJ/kg), showed that Brazil nut residues, an Amazon Forest waste, have great potential in pyrolysis applications for the generation of renewable energy, which can contribute to forest preservation through the development of the circular bioeconomy.

Wirksamkeit der Hörgeräteversorgung bei hochgradigem Hörverlust

HintergrundIn der Praxis liegt das unilaterale Einsilberverstehen mit Hörgerät bei 65 dB SPL (EV65(HG)) häufig unter dem maximalen Einsilberverstehen aus dem Sprachaudiogramm (mEV), insbesondere bei Hörgeräteträgern mit hochgradigem Hörverlust. Diese Arbeit zielte darauf ab, den Wirkungsgrad Q der Hörgeräteversorgung, den Quotienten aus EV65(HG) und mEV, bei Hörgeräteträgern mit hochgradigem bis an Taubheit grenzendem Hörverlust zu untersuchen.Material und MethodenEs wurden Daten aus In-situ-Messungen, dem Reinton- und Sprachaudiogramm und dem Sprachverstehen mit und ohne Hörgerät von 93 Ohren von 64 Patienten ausgewertet. Die Patienten stellten sich im Jahr 2019 für eine Hörgerätekontrolle in unserem Hörzentrum vor. Es wurden die Abweichung der in-situ gemessenen frequenzabhängigen Ausgangspegelwerte von den Zielvorgaben der präskriptiven Anpassformeln NAL-NL2 und DSL v5.0 analysiert. Für die Parameter EV65(HG) und Q wurden jeweils die Spearman-Korrelationskoeffizienten für den Sprachverständlichkeitsindex (SII) berechnet.ErgebnisseBei mehr als 67 % der Hörgeräteeinstellungen stimmten die Ausgangspegelwerte mit den Zielkurven für NAL-NL2 oder DSL v5.0 im Bereich von ±5 dB für Frequenzen von 0,5 bis 4 kHz für 65 dB SPL überein. Trotzdem wurde das mEV mit Hörgerät bei 65 dB SPL nicht erreicht (mittlere Abweichungen: 34,4 %). EV65(HG) und Q waren jedoch am besten, wenn Zielwerte für DSL v5.0 bei 65 dB SPL erreicht wurden, was mit einem höheren SII einhergeht.SchlussfolgerungFür Hörgeräteträger mit hochgradigem bis an Taubheit grenzendem Hörverlust führen die Anpassformeln NAL-NL2 und DSL v5.0 nicht zu einer solchen Verstärkung, dass bei Alltagssprache von 65 dB SPL das mEV erreicht wird. Es bleibt zu untersuchen, ob alternative Präskriptionen mit besserer Hörbarkeit für Eingangspegel von 50 und 65 dB SPL den Wirkungsgrad der Hörgeräteversorgung verbessern könnten.

Impact of aqueous micellar media on biocatalytic transformations involving transaminase (ATA); applications to chemoenzymatic catalysis

Surfactant-enabled asymmetric ATA-catalyzed reductive aminations in aqueous buffered media are described, representative of the enhanced levels of conversion made possible by the presence of a nonionic surfactant in the water, thereby enabling 1-pot chemoenzymatic catalysis.

Thermal analysis and phase changes of mechanochemically activated sodium carbonate

Sodium carbonate is a well-known material for being used as a good sorbent of carbon dioxide from the atmosphere, and as such has gained increasing importance in environmental protection. In order to enhance its sorption ability, mechanochemical activation of sodium carbonate was carried out in this study while the occurred changes after the activation and the relaxation time in a controlled environment were monitored. Activation was performed in a vibro-mill from 1 to 28 min. Based on the results of specific surface area, obtained by BET, the samples activated for 2 and 7 min were chosen and placed in a moist carbon dioxide atmosphere for 96 h, a period called the relaxation time. Differential thermal and thermogravimetric analyses were applied with the aim of determining the changes that occurred on the activated samples during the relaxation period. The decomposition temperature change of activated Na2CO3 samples, as well as mass loss and conversion level of Na2CO3 to NaHCO3 were monitored depending on activation and relaxation time periods. The conversion reactions of sodium carbonate to sodium bicarbonate under the specified environment of carbon dioxide and moisture were also studied, and the thermodynamic data such are changes in enthalpy, entropy, and Gibbs energy at the temperature range of 0–160 °C are given.

In situ configuration of dual S-scheme BP/(Ti3C2Tx@TiO2) heterojunction for broadband spectrum solar-driven photocatalytic H2 evolution in pure water

Artificial photocatalysis with high-efficiency is a promising route for storing sustainable energy from water splitting. Whereas it is challenging to broaden the solar-spectrum responsive window for harvesting high level of conversion. Herein, based on the band-matching engineering theory, a design of dual S-Scheme heterojunction system is proposed and established in a BP/(Ti3C2Tx@TiO2) composite photocatalyst. The complementary light response region between TiO2 and BP realizes the extension of solar energy utilization over a broad absorption window. Furthermore, this specific band-matching configuration endows spatially long-lived charge carriers with greater accumulation on the divided sub-systems, thereby maintaining the sufficient potential energy capacity associated with excellent photocatalytic properties (H2 evolution rate of 564.8 μmol h−1 g−1 and AQE of 2.7% at 380 nm in pure water). This work describes a promising protocol of designing advanced broadband light-activated photocatalytic systems for solar-chemical energy conversion applications.

Exploring the Irony in Japanese Popular Culture. A Cross-Cultural and Linguistic Analysis.

The present study addresses the status and use of irony in Japanese popular culture by closely examining its’ cultural variations on a corpus consisting of ironic utterances and situations from three popular culture media: Japanese drama, anime, and manga. While it is likely that Western popular culture abounds in ironic aesthetics and standpoints, the concept of “irony” faces cultural reconstruction within Japanese culture and society, a fact easily reflected in national media and cinematographic productions. In such cases, the cultural and linguistic distance between Japanese and English, and the striking difference, which exists between these two geographical and cultural contexts, increase the challenge interposed by the understanding and interpreting of irony. Moreover, on a conversational level, ironizing one’s communication partner is considered socially unacceptable and penalised accordingly. It stands against the much-expected politeness and traditional Japanese concepts such as “honne” and “tatemae,” which, if preserved, can create harmony in communication. In conclusion, the ambiguous definition of irony, together with the negative perception and reluctance of Japanese people towards its usage, has contributed to frequently branding irony strictly as a Western phenomenon. However, as the present research attempts to demonstrate, the usage of irony in Japanese popular culture embraces multifarious approaches, and it extends to reach the borders of semantics.

Comparative Microbial Conversion of Deoxynivalenol and Acetylated Deoxynivalenol in Different Parts of the Chicken Intestine as Detected In Vitro and Translated to the In Vivo Situation.

To assess potential differences in the intestinal microbial metabolism of deoxynivalenol (DON) and its acetylated forms 3-Ac-DON and 15-Ac-DON, in vitro anaerobic incubations with intestinal contents from chickens were conducted. Quantitative microbiota characterization was obtained by 16S rRNA sequencing. The data showed substantial differences in the level of different toxin conversions by the microbiota from the different intestinal segments. The transformation rate of DON to its metabolite DOM-1 decreased in the order of cecum > ileum > jejunum, and caecum contents could completely transform DON to DOM-1 within 24 h. However, no transformation appeared in the duodenum. For 3-Ac-DON, the deacetylation rate decreased as follows: duodenum > caecum > ileum > jejunum, and 100% deacetylation was observed in the duodenum within 24 h. The deacetylation of 15-Ac-DON decreased in the order of cecum > duodenum > ileum with no transformation in the jejunum. Some genera may contribute to the transformation of the toxins. Based on the in vitro kinetic parameters and their scaling to the in vivo situation, it was concluded that in the chicken small intestine, the deconjugation of both 3-Ac-DON and 15-Ac-DON will not likely be completed upon full transit. Whether this also holds for humans remains to be established.

Phase-Transition Process in the Hydrothermal Zeolitization of Volcanic Ash into LTA and FAU Structures

AbstractMinerals such as quartz, present widely in various volcanic ashes, remain unaltered throughout the low-temperature hydrothermal process currently used in industry to obtain zeolites, causing an incomplete hydrothermal transformation of the starting solid. This study presents a novel and cost-effective procedure which improves the reactivity of ash toward the generation of zeolite by increasing the availability of silica and alumina components. This method leads to a final product with a large zeolite content. The transformation consisted of an ash-activation step followed by hydrothermal zeolitization. The influence of the structural, chemical, and morphological characteristics of the volcanic ash as well as the effect of the activation procedure on the ash reactivity were studied. A collected sample (VA) and an amorphous fraction obtained after VA sieving (VA40, retained on #40 mesh) were used for zeolite production. These solids were alkaline-treated separately, aged, and reacted under controlled conditions of temperature at autogenous pressure. Throughout the process, the solid phases were characterized by X-ray diffraction, energy dispersive X-ray microanalysis, scanning electron microscopy, Fourier-transform infrared spectroscopy, and N2adsorption-desorption porosimetry measurements. After activation and alkaline aging, the presence of quartz and plagioclase minerals in the natural ash seemed to improve the growth of NaAlSiO4 polymorphs, which in turn were transformed easily to zeolite structures. Even under adequate pretreatment and suitable synthesis conditions, the coarse non-crystalline fraction led to low conversion, while the highest conversions to zeolites A and X were obtained from the natural ash. The outcomes of the present study could be used to improve the conversion levels of other non-conventional aluminosiliceous minerals into zeolites.

Combustion performance of fine screenings from municipal solid waste: Thermo-kinetic investigation and deep learning modeling via TG-FTIR

The combustion behavior, kinetics, thermodynamics and gas products of fine screenings (FS) classified from municipal solid waste (MSW) in an air atmosphere were explored by TG-FTIR. A deep learning model was established using 1D–CNN–LSTM algorithm to predict thermogravimetric data of FS combustion, with visualization technology (TensorBoard) applied to display the weights and biases in various cells. The thermogravimetric analysis (TG) and differential thermal gravity (DTG) curves indicated that the FS combustion process can be divided into four stages. The average activation energy (Ea) of FS combusted at different stages, exhibited different change tendencies with increasing levels of conversion (α). The highest enthalpy (ΔH) of 206.40 kJ/mol and free Gibbs energy (ΔG) of 55.03 kJ/mol emerged in stage Ⅳ, while the highest changes of entropy (ΔS) of 169.11 J/(mol·K) occurred in stage Ⅱ. The main gas products (CO2, H2O and CO) and functional groups (CO and phenols) were all detected. For the 1D–CNN–LSTM model, the optimal settings for the prediction of thermogravimetric data were a neuron number of 150, dropout of 0.003, epoch number of 200, and batch size of 25. The highest correlation coefficient (R2) of 94.41% was obtained using the optimum model parameters, achieving an excellent prediction performance.

20 years after To Err Is Human: A bibliometric analysis of ‘the IOM report’s’ impact on research on patient safety

Modern safety science owes much of its current theories and practical approaches to the critical analysis of socio-technological disasters in the nuclear, chemical, maritime, and aviation industries at the end of the 1970 s and in the 1980 s. The medical field by contrast, was not challenged by a single high profile event, but by the release of a single report by the Institute of Medicine in 1999: To Err is Human – Building a Safer Health System. The report expanded the level of conversation and concern about patient injuries in health care and led to an unprecedented provision of research grants in patient safety research, essentially launching the academic base for that work. Twenty years later, it is a good time to analyze how this seminal work was received in the academic literature, which authors and institutions had the greatest research activity, which national and international collaborations ensued, and how the ideas presented in To Err Is Human might have affected the academic discourse in the two decades to follow.To meet this aim, a bibliometric analysis was performed on all publications from 2000 to 2019 where the authors referenced To Err Is Human as part of their scientific argument. 20.494 documents were retrieved. The majority of patient safety related research was carried out by researchers from North America, with little international collaboration. Over the years, the thematic scope of the research diversified from the IOM report’s initial focus in many directions. Contrary to what might be expected from the IOM report’s central objectives, research on a systems approach to patient safety and on incident reporting were underrepresented. From a safety science perspective, the report narrowed the diversity of the patient safety discourse rather than enlarging it by favoring the theoretical framework proposed by James Reason over other, equally valid ones.

Effect of decalin as hydrogen-donor for in-situ upgrading of heavy crude oil in presence of nickel-based catalyst

The effect of decalin as hydrogen-donor on the catalytic and non-catalytic hydrothermal upgrading of heavy crude oil was studied. The donating (dehydrogenation) capacity and conversion of decalin in presence of nickel-based catalyst (nickel (II) stearate) were evaluated. In addition, the changes in composition of dehydrogenated products, release and consumption of hydrogen during decalin dehydrogenation in presence and absence of Ni-stearate and heavy crude oil were studied. All of the upgrading and dehydrogenation experiments were carried out at 300 °C, 72 bar (1044.27 psi) and 24 h of reaction time. The upgrading of heavy crude oil in presence of decalin and Ni-stearate exhibited a good performance for conversion of decalin as well as for promoting the in-situ upgrading of heavy crude oil. The maximum decalin conversion level was found to be 21.95% in the presence heavy crude oil, water and nickel stearate. Ni-stearate was mainly in-situ transformed into particles of NiO and Ni3S2, which took the role of active phases for catalyzing the dehydrogenation of decalin and promoting heavy crude oil upgrading. The use of decalin as a hydrogen-donor together with catalyst resulted in high viscosity reduction (69.2%), increase of saturates content (especially low molecule weight alkanes C10-C20), decrease of resins and asphaltenes content, and removal of sulfur and nitrogen.

Comparative Performance of PETase as a Function of Reaction Conditions, Substrate Properties, and Product Accumulation.

There is keen interest to develop new technologies to recycle the plastic poly(ethylene terephthalate) (PET). To this end, the use of PET-hydrolyzing enzymes has shown promise for PET deconstruction to its monomers, terephthalate (TPA) and ethylene glycol (EG). Here, the Ideonella sakaiensis PETase wild-type enzyme was compared to a previously reported improved variant (W159H/S238F). The thermostability of each enzyme was compared and a 1.45 Å resolution structure of the mutant was described, highlighting changes in the substrate binding cleft compared to the wild-type enzyme. Subsequently, the performance of the wild-type and variant enzyme was compared as a function of temperature, substrate morphology, and reaction mixture composition. These studies showed that reaction temperature had the strongest influence on performance between the two enzymes. It was also shown that both enzymes achieved higher levels of PET conversion for substrates with moderate crystallinity relative to amorphous substrates. Finally, the impact of product accumulation on reaction progress was assessed for the hydrolysis of both PET and bis(2-hydroxyethyl) terephthalate (BHET). Each enzyme displayed different inhibition profiles to mono(2-hydroxyethyl) terephthalate (MHET) and TPA, while both were sensitive to inhibition by EG. Overall, this study highlights the importance of reaction conditions, substrate selection, and product accumulation for catalytic performance of PET-hydrolyzing enzymes, which have implications for enzyme screening in the development of enzyme-based polyester recycling.

Fiscal Policy of Economic Development: Comparative Characteristics of Ukraine and Poland

In order to achieve the purpose outlined, this research uses the following methods: analysis and synthesis; economic and statistical analysis and comparison; economic and mathematical; generalization. The result shows that Poland's fiscal policy aims at developing economic infrastructure and building an economic model of the state based on the manufacture of products with a high share of value-added. However, the fiscal policy of Ukraine does not have significant effects on economic development due to the use of such instruments as public debt and capital expenditures. However, the external debt dependence of the state is relatively high. Nevertheless, it proves that the fiscal policy of Ukraine does not increase the level of economic complexity and development of the processing industry through the implementation of tax benefits. It proposes to increase the efficiency of tax authorities in Ukraine in terms of combating the shadow economy, boost the share of capital expenditures and raise the level of conversion of public debt into economic growth.JEL Classification: E62, F63, H21How to Cite:Petrunenko, I., Lavrov, R., Kuybida, V., Slatvinskyi, M., &amp; Zelenskyi, A. (2021). Fiscal Policy of Economic Development: Comparative Characteristics of Ukraine and Poland. Etikonomi, 20(2), xx– xx. https://doi.org/10.15408/etk.v20i2.22013.

Effect of a pulsating flow on hydrodynamics and fluid catalytic cracking chemical reaction in a circulating fluidized bed riser

The three-dimensional computational fluid dynamics (3D-CFD) of a pulsating flow applied to the fluid catalytic cracking (FCC) reaction was investigated in the riser of a circulating fluidized bed reactor. The kinetic parameters of the FCC and coke burning reactions for predicting the reactant conversion and product yield percentages were applied. To increase the reactant conversion level and product yield, the effect of the pulsating flow operating parameters was considered using a 2k statistical experimental design with four factors (amplitude, frequency, types of the waveform, and amplitude ratio). The 3D-CFD simulation was successfully validated from the experimental literature data. The frequency and type of the waveform were found to be the significant operating parameters. The expression of the fitted regression model and response surface contour were derived and revealed that the pulsating flow provides a higher reactant conversion level and product yield percentages compared to a non-pulsating or steady flow.