Semi-industrial Scale Research Articles

Catalytic Biolubricant Production from Canola Oil Through Double Transesterification with Methanol and Neopentyl Glycol

In the current environmental scenario, the proposal of alternatives for petroleum-based products has considerably increased, with the aim of looking for bioproducts with interesting properties such as biodegradability, sustainability and efficiency, among others. In this sense, the role of biolubricants is promising, offering a wide range of possibilities through different methods and operating conditions. Specifically, double transesterification could be a suitable process in a biorefinery context. The aim of this work was to produce a biolubricant through double transesterification with methanol and neopentyl glycol (NPG) under different reaction conditions by using homogeneous catalysis (sodium methoxide). Different catalyst concentrations, among other changes in reaction conditions (temperature ranging between 100 and 140 °C and NPG/FAME ratios between 0.5 and 2), were used, obtaining high conversion values (96%) and a final product with a high viscosity (20.7 cSt), which allows for its use as engine oil (SAE 5W). In conclusion, biodiesel and biolubricant production was feasible through homogeneous catalysis, proving the feasibility of this process at the laboratory scale. Further studies, including the use of different heterogeneous catalysts, as well as the implementation of this process at a semi-industrial scale, are recommended.

Effect of volumetric concentration factor on virus removal for low-pressure reverse osmosis membrane in drinking water production: A study on different scales

Reverse osmosis membranes are intended to constitute a complete physical barrier against nanometric-sized pathogens such as enteric viruses. Literature describes that low-pressure reverse osmosis achieves high viral removal rates (above 5 log), surpassing those of ultrafiltration (1 to 3 log). However, these studies often used individual viruses and high feed viral concentrations (above 109 virus L-1), greater than typical viral concentrations present in the environment like groundwater, to promote virus detection in the permeate. These high concentrations can promote viral aggregation, potentially affecting the observed retention. This work evaluates the simultaneous elimination of three viruses during the production of drinking water by low-pressure reverse osmosis: two enteric viruses (adenovirus 41 and coxsackievirus-B5) and bacteriophage MS2, a widely used virus surrogate in the literature. The permeates produced by low-pressure reverse osmosis were concentrated to allow virus detection in permeate at lower feed concentrations (106 virus L-1) while staying above the limits of detection and quantification. Experiments were carried out on two pilot plants of different scales (laboratory and semi-industrial) to assess the potential effect of the number of membranes and O-rings on virus retention. The effect of the volume concentration factor on low-pressure reverse osmosis efficiency was evaluated for each scale. Results indicate an average viral reduction of 6 log (up to 7 log), regardless of the size of the virus and/or the scale of LPRO pilot. For the semi-industrial scale, better retention was observed as the volume concentration factor increased. However, viruses were still present in the permeate for each scale (even if close to the detection limit), indicating that retention was not complete. At the same feed viral concentrations, the number of viruses recovered in the semi-industrial scale permeates was higher than in the laboratory scale. A 24-fold greater number of membranes and O-rings used for the semi-industrial scale showed that micro-leaks through O-rings could be responsible for the passage of viruses into the permeate.

Microencapsulation by Complex Coacervation of Lavender Oil Obtained by Steam Distillation at Semi-Industrial Scale.

Lavender oil (LEO) is one of the most well-known essential oils worldwide which, besides its extensive application in aromatherapy, serves as raw material for various fields, including the food, cosmetic, and pharmaceutical industries. Accordingly, several global requirements were established to warrant its quality. Microencapsulation represents an emerging technology widely applied for the preservation of essential oils, simultaneously providing new ways of application. In the current study, lavender oil was obtained from the flowering tops of Lavandula angustifolia Mill. on a semi-industrial-scale steam distillation system. According to the GC-MS investigation, lavender oil obtained in the third year of cultivation met the European Pharmacopoeia standards for linalyl acetate and linalool contents ≈38% and ≈26%, respectively. Microcapsules (MCs) containing the so-obtained essential oil were successfully produced by complex coacervation technology between gum arabic (GA) and three different grades of type-A gelatin (GE). Optical microscopic investigations revealed a significant difference in particle size depending on the gelatin grade used. The variation observed for coacervates was well reflected on the scanning electron micrographs of the freeze-dried form. The highest encapsulation efficiency values were obtained by UV-VIS spectrophotometry for microcapsules produced using gelatin with the medium gel strength. FT-IR spectra confirmed the structural modifications attributed to microencapsulation. According to the GC-MS analysis of the freeze-dried form, the characteristic components of lavender oil were present in the composition of the encapsulated essential oil.

Pyrolysis of End-Of-Life Tires: Moving from a Pilot Prototype to a Semi-Industrial Plant Using Auger Technology.

This work, carried out within the framework of the BlackCycle project, demonstrates the robustness of an auger reactor for the pyrolysis of end-of-life tires (ELTs) to be considered within the seventh level of technology readiness (TRL-7). For this purpose, the resulting pyrolysis products are compared with those obtained from a pilot scale facility ranging within the fifth technology readiness level (TRL-5). Using the same type of ELTs, tire trucks (TTs), operating conditions used at the TRL-5 plant are attempted to mimic those expected at a semi-industrial plant: tailored temperature profile (450, 550, and 775 °C) and residence time for vapors (30 s) and solids (15 min). The feed mass rate is 4 and 400 kg/h for the pilot and semi-industrial plants, respectively. The yields of tire pyrolysis oil (TPO), tire pyrolysis gas (TPG), and raw recovered carbon black (RRCB) from both plants, as well as their key properties and characteristics, are in good agreement with each other. The TPO produced by both plants contains comparable concentrations of value-added chemicals such as benzene, toluene, xylene, ethylbenzene, and limonene. There is also a very similar pattern between the simulated distillation curves. The TPG obtained from both plants is also very rich in H2 and CH4 and has a lower calorific value of 52-54 MJ/Nm3 (N2 free basis). Although the RRCBs produced by the two plants are more demanding and require more labor, they do have a number of comparable characteristics. All this information demonstrates not only the reliability of the experimental campaigns to scale up the pyrolysis process but also the robustness of the semi-industrial scale plant based on the auger technology to be classified at TRL-7.

Upgrading hazelnut skins: Green extraction of polyphenols from lab to semi-industrial scale

Hazelnut skins (HS) are usually managed as waste; however, this by-product is a source of bioactive compounds, with potential applications in feed and food sectors. Phenolic compounds can be extracted using green protocols combining enabling technologies and green solvents. This work investigates subcritical water extraction (SWE) of bioactive compounds from HS. A laboratory-scale study was performed on four different batches, with significant batch-to-batch heterogeneity. The evaluation of polyphenolic profiles and antioxidant activities afforded promising results compared to the benchmark of reflux maceration. To evaluate process effectiveness, the extraction protocol was replicated on a semi-industrial plant that processed 8 kg of matrix. Downstream processes have been optimized for scale-up, demonstrating the effectiveness of SWE in retaining product concentration and bioactivity avoiding excipients in spray-drying phase. Hazelnut extracts exhibited antibacterial properties against animal- and food-borne pathogens, supporting their potential use as sustainable feed ingredients for improved hazelnut production and animal farming practices.

Scale-up of plug-flow reactors in anaerobic treatment of agro-industrial wastes

This study is aiming to evaluate the optimization potential of anaerobic digestion systems for the treatment of complex agro-industrial wastes at an industrial scale. In previous work, the performance of a 20 L pilot-scale Plug Flow Reactor (PFR) that was able to operate at Organic Loading Rates (OLRs) of up to 25 kg Chemical Oxygen Demand (COD) m−3 d−1, was demonstrated. This concept was then successfully transferred in a semi-industrial scale PFR of a volume equal to 50 m3, and the optimal operational parameters were evaluated. The construction of a full industrial scale facility followed, utilizing initially a 380 m3 PFR. Since PFR systems in practice do not behave ideally, due to short Length to Diameter ratio (L/D) and/or higher axial dispersion, the ideal PFR behavior was compared with real data of the non-ideal industrial-scale system; a performance reduction of 25–30 % was detected. However, the disadvantage of the non-ideal behavior of PFRs can be overcome by the cascaded arrangement of two such reactors (2 × 380 m3 PFRs), leading to a total volume reduction of 35 %, as depicted by experimentation on the industrial scale cascaded PFRs. The optimal design parameters for the PFRs are provided.

Scaling up gaseous chlorine dioxide (ClO2) treatment in the cold storage of fresh apples

Novel interventions are needed to mitigate microbial risks, like Listeria monocytogenes, before shipping fresh apples to retail markets. Batch gaseous chlorine dioxide (ClO2) in-storage treatments were conducted to assess the inactivation of Listeria innocua, reduction of spoilage microorganisms, and changes in quality. Gaseous ClO2 was generated using equal amounts of dry precursors inside the modified commercial refrigerator with 82 kg and 330 kg apples for pilot and semi-industrial scale experiments, respectively. A cocktail of L. innocua was spot inoculated on the calyx of fresh Fuji apples and treated with an initial ClO2 input of 1.2 g of each precursor/kg of produce at a pilot scale for 30 d and semi-industrial scale for 90 d. Headspace ClO2 concentrations, temperature, and relative humidity were measured during the batch treatments. Reductions of 1.4±0.2 and 1.2 log CFU/mL of Listeria innocua were achieved by pilot-scale and semi-industrial scale trials, respectively. The presence of spoilage microorganisms was not significantly (P>0.05) impacted, and apples displayed no signs of deterioration. This study confirms that ClO2 can significantly inhibit foodborne pathogens, such as Listeria, during prolonged cold storage and reduce the risk of contamination for apple growers.

In vitro and in vivo antimicrobial activity of the fumigant, ethyl formate, against bacteria and fungi of date fruits in postharvest phase

The search is on for safer alternatives to fumigants like methyl bromide and phosphine, which harm the ozone layer and pose other risks. Ethyl formate is a promising candidate due to its potential antimicrobial and insecticidal action in stored products like date fruits. The susceptibility of date fruits to microbial spoilage is significantly influenced by factors such as moisture content, storage practices, and environmental conditions. In the present study, the in vitro antimicrobial effect of ethyl formate against three microbial species, namely Aspergillus niger F4, Mucor circinelloides YMM22, and Pseudomonas aeruginosa B1 was tested under laboratory conditions. In addition, two common date fruit varieties, semi-dry El-Wady I and the dry Frehi, were fumigated with ethyl formate alone in a laboratory-scale prototype and with a mixture of ethyl formate and CO2 at a semi-industrial scale prototype. Both varieties had an initial moisture content of around 13.40 and 12.48% for El-Wady I and Frehi, respectively. The fumigation was conducted using the optimal concentration of 70 mg/L air for 24 h incubation period. Fumigation with ethyl formate alone or in combination with CO2 significantly reduced the number of viable bacteria and fungi (CFU/g), but the potential for a combined effect with CO2 was not investigated. The percentages of reduction in the fungal count were 78.18 and 90.76% for Frehi and El-Wady I varieties, respectively in a semi-industrial scale prototype. Moreover, the percentages of reduction in the bacterial count were 53.31 and 65.20%, respectively for Frehi and El-Wady I varieties. Ethyl formate showed promise as a natural alternative to control microbial contamination of stored date fruits. Further research suggests that increasing fumigation duration or concentration could provide comprehensive control of microbial pathogens at all stages of development.

Protein Ingredient Quality within Infant Formulas Impacts Plasma Amino Acid Concentrations in Neonatal Minipiglets

BackgroundInfant formulas (IFs), the only adequate substitute to human milk, are complex matrices that require numerous ingredients and processing steps that may impact protein digestion and subsequent amino acid (AA) absorption. ObjectivesThe objective was to understand the impact of the protein ingredient quality within IFs on postprandial plasma AA profiles. MethodsFour isonitrogenous and isocaloric IFs were produced at a semi-industrial scale using whey proteins from different origins (cheese compared with ideal whey) and denaturation levels (IF-A, -B, -C), and caseins with different supramolecular organizations (IF-C, -D). Ten Yucatan minipiglets (12- to 27-d-old) were used as a human infant model and received each IF for 3 d according to a Williams Latin square followed by a 2-d wash-out period. Jugular plasma was regularly sampled from 10 min preprandial to 4 h postprandial on the third day to measure free AAs, urea, insulin, and glucose concentrations. Data were statistically analyzed using a mixed linear model with diet (IFs), time, and sex as fixed factors and piglet as random factor. ResultsIFs made with cheese whey (IF-A and -B) elicited significantly higher plasma total and essential AA concentrations than IFs made with ideal whey (IF-C and -D), regardless of the pre- and postprandial times. Most of the differences observed postprandially were explained by AA homeostasis modifications. IFs based on cheese whey induced an increased plasma concentration of Thr due to both a higher Thr content in these IFs and a Thr-limiting degrading capability in piglets. The use of a nonmicellar casein ingredient led to reduced plasma content of AA catabolism markers (IF-D compared with IF-C). ConclusionsOverall, our results highlight the importance of the protein ingredient quality (composition and structure) within IFs on neonatal plasma AA profiles, which may further impact infant protein metabolism.

The effect of slag variability in the attempted manufacture of AYF (alite-ye'elimite-ferrite) cement clinker at both laboratory and pilot scale

The production of AYF (alite-ye'elimite-ferrite) clinker was tested at laboratory and semi-industrial scale using by-products from the metallurgical industry: AOD slag; ladle slag; and fayalitic slag. Alite could be produced with ye'elimite using fluorine originating from AOD (argon oxygen decarburisation) slag as a mineraliser. After a successful laboratory demonstration, the clinker production was scaled to a semi-industrial trial. It was discovered that the reason for the absence of alite formation in a semi-industrial demonstration was that the AOD slag from the specific batch did not perform the designed mineralisation effect for alite formation. This study demonstrates that alite-ye'elimite can be produced at 1260 °C at laboratory scale by using fluorine mineralisation originating from an industrial by-product – in this case, AOD slag. However, the utilisation of by-products for delicate reactions requires detailed determination of the properties of the slag, as the variability from the same source yields different clinker chemistries and mineral phases.

Performance and cost–benefit analyses of an integrated process for advanced treatment of highly saline textile wastewater at a semi-industrial scale

Performance and cost–benefit analyses of an integrated process for advanced treatment of highly saline textile wastewater at a semi-industrial scale

Experimental investigation of hydrogen enriched natural gas combustion with a focus on nitrogen oxide formation on a semi-industrial scale

Combustion of hydrogen-enriched natural gas is a valuable short-term strategy for reducing CO2 emissions from high temperature industrial heating. This paper presents several experiments on combustion characteristics and the formation of nitrogen oxides. The experiments included hydrogen contents up to 100% and fuel heat inputs up to 75 kW. Water-cooled lances were used to influence the furnace temperature. The analysis includes the distribution of furnace temperatures, the composition of flue gas, the cooling capacity of the lances under steady-state operating conditions, and OH*-chemiluminescence imaging of the near burner region. The presented results demonstrate the dependence of furnace conditions and NOX formation on various factors, such as different air inlet fluxes, furnace temperature, and fuel composition, for constant heat inputs. Efficiency increased by up to 5.5% and significant changes in flame shaped along with a maximum increase in NOX emissions when comparing natural gas to hydrogen was measured at 167%.

Preconcentration of a Medium-Grade Celestine Ore by Dense Medium Cyclone Using a Factorial Design

A semi-industrial scale hydrocyclone with a 250 mm internal diameter was used to concentrate medium-grade celestine ore (75%–85% celestine) from the Montevive deposit of Granada (Spain) using a dense ferrosilicon (FeSi) medium. For this purpose, a Box–Behnken factorial design (BBD) was carried out, with the response variable being the Sr concentration measured by X-ray fluorescence (XRF), as well as the concentration of celestine measured by X-ray diffraction (XRD) of the mineral collected from the under (sunk) stream of the hydrocyclone. The experimental factors to be optimised were the density of the medium in the mixing tank (water, FeSi, and feed mineral) varying from 2.7 to 2.9 kg/L, the hydrocyclone inlet pressure from 0.8 to 1.2 bar, and the hydrocyclone inclination (from 15° to 25° from the horizontal). The range of densities of the dense medium to be tested was determined from previous sink–float experiments using medium-grade ore, in which the distribution of mineral phases with different particle size fractions was determined. To evaluate the separation behaviour, the following parameters were considered: the enrichment ratio (E), the tailings discarding ratio (R), and the mineral processing recovery (ε). From the factorial design and the response surface, the optimum parameters maximising celestine concentration in the under stream (78%), were determined. These optimised parameters were: a density of 2.75 kg/L for the dense medium, an inlet pressure of 1.05 bar, and a hydrocyclone inclination varying from 18° to 20°. Under these conditions, a 94% recovery of celestine (68% Sr) can be achieved. These results show that medium-grade celestine ore, accumulated in mine tailings dumps, can be effectively concentrated using DMS hydrocyclones and that the operating parameters can be optimised using a factorial experiment design. This study can contribute to reducing overexploitation of strategic mineral resources, avoiding blasting and environmentally damaging clearing, by applying a simple and sustainable technique.

Bacteria Associated with Spores of Arbuscular Mycorrhizal Fungi Improve the Effectiveness of Fungal Inocula for Red Raspberry Biotization

Intensive crop production leads to the disruption of the symbiosis between plants and their associated microorganisms, resulting in suboptimal plant productivity and lower yield quality. Therefore, it is necessary to improve existing methods and explore modern, environmentally friendly approaches to crop production. One of these methods is biotization, which involves the inoculation of plants with appropriately selected symbiotic microorganisms which play a beneficial role in plant adaptation to the environment. In this study, we tested the possibility of using a multi-microorganismal inoculum composed of arbuscular mycorrhizal fungi (AMF) and AMF spore-associated bacteria for biotization of the red raspberry. Bacteria were isolated from the spores of AMF, and their plant growth-promoting properties were tested. AMF inocula were supplemented with selected bacterial strains to investigate their effect on the growth and vitality of the raspberry. The investigations were carried out in the laboratory and on a semi-industrial scale in a polytunnel where commercial production of seedlings is carried out. In the semi-industrial experiment, we tested the growth parameters of plants and physiological response of the plant to temporary water shortage. We isolated over fifty strains of bacteria associated with spores of AMF. Only part of them showed plant growth-promoting properties, and six of these (belonging to the Paenibacillus genus) were used for the inoculum. AMF inoculation and co-inoculation of AMF and bacteria isolated from AMF spores improved plant growth and vitality in both experimental setups. Plant dry weight was improved by 70%, and selected chlorophyll fluorescence parameters (the contribution of light to primary photochemistry and fraction of reaction centre chlorophyll per chlorophyll of the antennae) were increased. The inoculum improved carbon assimilation, photosynthetic rate, stomatal conductance and transpiration after temporary water shortage. Raspberry biotization with AMF and bacteria associated with spores has potential applications in horticulture where ecological methods based on plant microorganism interaction are in demand.

Preparation and Characterization of Soluble Dextrin Fibre from Potato Starch Obtained on a Semi-Industrial Scale

Currently, dietary fibre intake is low, which is one of the reasons for the global obesity epidemic and other metabolic disorders. Dietary fibre has many documented health-promoting properties, such as a prebiotic effect, inducing feelings of satiety and reducing postprandial glucose. Therefore, there is an increasing interest in the search for new products rich in dietary fibre. One of the sources of dietary fibre may be resistant dextrins obtained as a result of dextrinization of starch. In this study, soluble dextrin fibre (SDexF) was prepared by heating potato starch in the presence of hydrochloric and citric acids on a semi-industrial scale in the prototype dextriniser. The aim of the study was the optimisation of the preparation of SDexF on a semi-industrial scale and the physicochemical characterisation of the obtained product. Also, the molecular structure of the prepared product was analysed by using SEM and FTIR. The semi-industrial production of SDexF was successfully implemented, achieving approximately 100 times higher product quantities in one process cycle. SDexF was characterised by over 30% total dietary fibre (TDF) content, almost 100% water solubility, low viscosity and no retrogradation tendency. The physicochemical and functional properties of the obtained product indicate the possibility of implementing SDexF to enrich food products.

Authorizing of Immunogenicity of Concentrated and Purified Newcastle Disease Virus V4 Strain using Downstream Processing.

Newcastle disease virus (NVD) from the Paramyxoviridae family is a single-stranded negative-sense RNA virus. This infection can affect both domestic poultry and almost all other bird species. It has been considered a very severe difficulty for the poultry industry all over the world. Even though it remains a potential threat to poultry industries, this virus is a powerful oncolytic virus as well. In this study, a process was accomplished to achieve concentrated and highly purified NDV V4 strain particles. Downstream processing of Newcastle virus strain V4 was characterized by amplifying virus in embryonated chicken eggs. Through a sequence of steps, harvesting allantoic fluid, clarification by centrifuge, concentration by ultrafiltration, and size exclusion separation, the reduced volume and pure virus particles were considered for the amount of ovalbumin, hemagglutinin activity, transmission electron microscopy (TEM), electrophoresis, and additionally immunogenicity of prepared antigens. The results presented a high recovery of HA activity in concentrated and purified virus with the removal of ovalbumin and the typical morphology based on TEM. Sepharose CL-4B was determined as the best media among all used resins to purify the virus. Prepared formulations as vaccines demonstrated positive hemagglutinin inhibition for 6 months and stability for 2 years. Strong evidence from organized studies supports the effectiveness of this method in concentrating and purifying intact NDV, which could be valuable in vaccine research, antiserum preparation, or even as an alternative oncotic agent to traditional methods. Despite further studies being conducted, this method can be utilized particularly on a semi-industrial scale to produce various vaccine components.

Semi-industrial Bio-fabrication of ZnO/MnO2 Nanocomposite Using Endophytic Streptomyces coelicolor: Characterization, Statistical Design, Exponential Pulse Fed-Batch Fermentation, and Its Antimicrobial Application

In our study, we examined how well six Streptomyces strains bio-fabricated ZnONPs, MnONPs, and/or ZnO/MnO2 nanocomposite. The most potent strain that generated efficient antimicrobial nanoparticles was then picked to increase the production of those particles in a semi-industrial pilot plant unit. Consequently, the intracellular extract of endophytic Streptomyces coelicolor strain E72 was used to achieve the bio-fabrication reaction of the spherical ZnO/MnO2 nanocomposite (6–18 nm). The bio-fabricated ZnO/MnO2 nanocomposite was validated and characterized using FTIR, XRD, SEM, TEM, TGA, and EDS analyses. Additionally, the production of this ZnO/MnO2 nanocomponent was scaled up to a pilot plant unit with a semi-industrial size. The Plackett–Burman experimental method was used to maximize the production of ZnO/MnO2 nanocomposites, which had increased 2.7-fold from their initial state. The bio-fabricated ZnO/MnO2 nanocomposite was subsequently scaled up 31.25 times using an exponential pulse-feeding fermentation technique in a 70-L bioreactor. This ZnO/MnO2 nanocomposite exhibited effective antimicrobial efficacy against all tested antibiotic-resistant human pathogens. The antimicrobial effects against Salmonella paratyphi (53.17 ± 2.8 mm) and Candida albicans (50.2 ± 1.01 mm) were the most potent at 90 and 130 µg/ml of ZnO/MnO2 nanocomposite, respectively. This is the first full explanation of the ZnO/MnO2 nanocomposite bio-fabrication at a semi-industrial scale employing endophytic strain E72 extract as a reducing/capping agent that reacted with MnCl2·4H2O and Zn (CH3COO)2·2H2O as precursors. This bio-fabricated ZnO/MnO2 nanocomposite has the potential to be utilized in the development of pharmaceuticals, cosmetics, wound dressings, and burn therapy due to its powerful antimicrobial capabilities.

Method development and evaluation of product gas mixture from a semi-industrial scale fluidized bed steam cracker with GC-VUV

Steam cracking in fluidized beds offers an alternative to conventional steam cracking for sustainable hydrocarbon production. This approach has gained interest, particularly in the context of recycling plastics to generate valuable hydrocarbons. Integrating this process into existing petrochemical clusters necessitates a thorough characterization of the products derived from this new feedstock. This work focuses on addressing the challenges associated with species quantification and characterization time for assessing the product mixture resulting from a steam cracking process. The experiments were conducted in a semi-industrial scale dual fluidized bed steam cracker, utilizing polyethylene as the feedstock. To sample species spanning from C1 to C18, cooling, scrubbing, and adsorption were introduced. These steps were integrated with GC-VUV (Gas Chromatography with Vacuum Ultraviolet Spectroscopy) and other widely recognized analytical methods to quantify the sampled species. The primary focus was on GC-VUV analysis as a suitable characterization method for identifying and quantifying C4 to C18 species, which can constitute up to 35% of the product mixture obtained from polyethylene steam cracking (750 °C to 850 °C). Quantifying C6 to C18 hydrocarbons becomes the time-critical step, with GC-VUV potentially achieving this in 1/6th of the analysis time and with relatively optimal quantification compared to the traditional characterization methods.

Enhancing pure NH3 combustion: Impacts of O2 enrichment under MILD conditions in a 20-kW semi-industrial scale furnace

This experimental work provides insights into the effects of oxygen (O2) enrichment on pure ammonia (NH3) combustion in a 20-kW semi-industrial scale furnace featuring an industrial-grade burner operated under MILD/Flameless conditions. The impact of O2 enrichment on the NH3 combustion stabilization, the flame and furnace temperature, the exhaust emissions, and the OH* chemiluminescence were explored. The tests were conducted by varying O2 concentration in the oxidizer stream from 21 % to 50 % and using two different oxidizer injectors to achieve average inlet velocities of 80 m/s and 150 m/s while keeping the inlet power and the total oxidizer mass flow rate constant. Stable flameless combustion with a distributed reaction zone and a consistent and uniform temperature profile throughout the combustion chamber was achieved with O2 enrichments higher than 34 %. Nevertheless, high levels of NH3 slips were observed, which were drastically reduced to negligible concentrations at higher O2 enrichments. On the contrary, NO emissions increased with the O2 fraction with an opposite non-linear trend compared to that of NH3 slip. An optimum trade-off between NOx emissions and NH3 slip was achieved by co-firing NH3 with O2=37 % with ID16 and 36 % with ID20 injector. This study also compares the behavior of pure O2-enriched NH3 combustion under flame and MILD combustion conditions to highlight the advantages of oxygen-enhanced NH3 flameless combustion. While operating in flame mode ensured a stable ammonia oxidation process already at low O2 enrichment=30 %, NO emissions and NH3 slips were significantly higher than those measured under MILD conditions. Finally, the impact of varying industrial load and the related heat balance on the NH3 slip was assessed at different levels of O2 enrichments at a fixed equivalence ratio. The overall results show that O2-enriched flameless ammonia combustion can simultaneously expand the range of stable combustion and reduce NO and NH3 emissions.

Production of antimicrobial nonwoven fabrics based on recycled polyethylene terephthalate (R-PET) fibers on industrial scale

One of the ultimate goals of this article is to produce antimicrobial polyester nonwoven fabrics on industrial scale. Therefore, the adaptation and development of pilot conditions for imparting polyester textile materials antimicrobial properties is highly needed. This will pave the way for establishment a technological package for the production of antimicrobial polyester nonwoven fabrics on industrial scale. The effect of semi-industrial scale treatment conditions, mainly antimicrobial substrate (AS) concentration, duration, and temperature on the (%) colony forming unit (CFU) reduction after treatment with aqueous solutions of AS was examined. The antimicrobial activity of treated with AS fibers against S. aureus, E. coli, and C. albicans was investigated using the shake flask method. All PET fibers bounded with AS showed outstanding antimicrobial activities against the previously mentioned three microorganisms. In fact the % of CFU reduction for all PET samples were significant, whereas it was null for the parent fibers.