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1.
Waste Manag ; 183: 53-62, 2024 Jun 30.
Article in English | MEDLINE | ID: mdl-38718627

ABSTRACT

Advanced thermochemical technologies for plastic waste valorization represent an interesting alternative to waste-to-energy options. They are particularly appealing for waste-to-hydrogen and waste-to-chemicals applications, with autothermal steam-oxygen gasification in fluidized bed reactors showing the greatest market potential. The study describes a series of experimental tests carried out on a large pilot-scale fluidized bed gasifier, using steam and O2-enriched air, with increasing fractions of oxygen. Different values of the main operating parameters are varied: equivalence ratio (0.22-0.25), steam-to-carbon ratio (0.7-1.13), and steam-to-oxygen ratio (up to 3.2). The fuel consists of real mixed plastic waste coming from separate collection of municipal solid wastes. The data obtained are used to investigate in depth the role of the main operating parameters and to improve and validate a recently developed one-dimensional kinetic model for waste gasification. The validation shows a good agreement between experimental data and model results, suggesting the reliability of the model to predict the reactor behavior under conditions of pure steam-oxygen gasification, relevant to many industrial applications. It has been found that the equivalence ratio is the parameter that most affects the syngas composition. At a constant equivalent ratio, the molar fraction of oxygen in the enriched air shows a limited influence on syngas composition while the steam is crucial in controlling the temperature along the reactor. Provided that the steam-to-carbon molar ratio is larger than 1.5, steam affects mainly the reactor temperature rather than the syngas composition, qualifying the steam-to-oxygen molar ratio as an instrumental parameter for smooth plant operation.


Subject(s)
Oxygen , Plastics , Refuse Disposal , Steam , Oxygen/analysis , Refuse Disposal/methods , Pilot Projects , Solid Waste/analysis , Models, Theoretical , Gases/analysis
2.
Membranes (Basel) ; 14(4)2024 Apr 14.
Article in English | MEDLINE | ID: mdl-38668118

ABSTRACT

Pervaporation is a membrane-based process used for the separation of liquid mixtures. As this membrane process is governed by the differences in the sorption and diffusivities of separated components, close boiling mixtures and azeotropic mixtures can effectively be separated. The dehydration of ethanol is the most common application of hydrophilic pervaporation. The pilot scale properties of hydrophilic composite poly(vinyl alcohol) PVA membrane (PERVAPTM 2200) in contact with wet raw bioethanol are presented. The wet raw bioethanol was composed of ethanol (82.4-89.6 wt%), water (5.9-8.5 wt%), methanol (2.3-6.9 wt%), cyclohexane (0.2-2.4 wt%), higher alcohols (0.2-1.3 wt%), and acetaldehyde (0.004-0.030 wt%). All experiments were performed using a SULZER ECO-001 plant equipped with a 1.5 m2 membrane module. The efficiency of the dehydration process (i.e., membrane selectivity, permeate flux, degree of dehydration) was discussed as a function of the following parameters: the feed temperature, the feed composition, and the feed flow rate through the module. It was found that the low feed flow rate influenced the dehydration efficiency as the enthalpy of evaporation caused a high temperature drop in the module (around 25 °C at a feed flow rate equal to 5 kg h-1). The separation coefficient during pervaporation was in the range of 600-1200, depending on the feed composition. The increase in temperature augmented the permeation flux and shortened the time needed to reach the assumed level of dehydration. It was revealed that dehydration by pervaporation using ECO-001 pilot plant is an efficient process, allowing also to investigate the influence of various parameters on the process efficiency.

3.
Environ Sci Pollut Res Int ; 31(13): 20556-20567, 2024 Mar.
Article in English | MEDLINE | ID: mdl-38376776

ABSTRACT

In this contribution, the performance of powdered titanium dioxide (TiO2)-based photocatalysts was evaluated in a pilot photocatalytic plant for the degradation of different dyes, with an investigated volume of 1 L and solar simulated light as irradiation source. Five different samples, synthesized in our laboratories, were tested in the pilot plant, each consisting of TiO2 nanoparticles (NPs) coupled with a different material (persistent luminescent material and semiconductor material) and treated in different thermal conditions. All synthesized samples have been subjected to X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Brunauer-Emmett-Teller analysis (BET), and transmission electron microscopy (TEM) characterization, to shed light on the influence of introducing other materials on titania characteristics. To study and evaluate the significance of the parameters affecting the process in the pilot plant, a chemometric approach was applied, by selecting a mathematical model (D-Optimal) to simultaneously monitor a large number of variables (i.e., 7), both qualitative and quantitative, over a wide range of levels. At the same time, the recovery of the synthesized photocatalysts was studied following a novel promising recuperation method, i.e., annulling the surface charge of the suspended samples by reaching the isoelectric point (pHPZC) of each sample, for the quantitative precipitation of TiO2 nanoparticles.


Subject(s)
Chemometrics , Nanoparticles , Microscopy, Electron, Transmission , Nanoparticles/chemistry , Coloring Agents/chemistry , Titanium/chemistry , Catalysis
4.
Bioprocess Biosyst Eng ; 47(2): 235-247, 2024 Feb.
Article in English | MEDLINE | ID: mdl-38170236

ABSTRACT

This paper presents the analysis of a pilot anaerobic digestion plant that operates with organic fraction of municipal solid waste (OFMSW) from a wholesale market and can treat up to 500 kg d-1. The process was monitored for a period of 524 days during which the residue was characterized and the biogas production and methane content were recorded. The organic load rate (OLR) of volatile solids (VS) was 0.89 kg m-3 d-1 and the Hydraulic Retention Time (HRT) was 25 d during the process. The yield was 82 Nm3 tons OFMSW-1 biogas, equivalent to 586 Nm3 tons CH4 VS-1. The results obtained in the pilot plant were used to carry out a technical-economic evaluation of a plant that treats 50 tons of OFMSW from wholesale markets. A production of 3769 Nm3 d-1 of biogas and 2080 Nm3 d-1 of methane is estimated, generating 35.1 MWh d-1 when converted to electricity.


Subject(s)
Refuse Disposal , Solid Waste , Solid Waste/analysis , Refuse Disposal/methods , Anaerobiosis , Biofuels , Bioreactors , Methane
5.
Environ Res ; 245: 118080, 2024 Mar 15.
Article in English | MEDLINE | ID: mdl-38171469

ABSTRACT

In the present work, the construction, and operation of a pilot-scale biogas upgrading system is presented, employing 2 commercial polyimide (PI) membranes. The Upgrading system treats biogas produced via anaerobic digestion of the sludge, produced from the treatment of municipal wastewater in the facilities of Thessaloniki's Wastewater Treatment Plant. The goal of the separation unit is the production of high purity biomethane (>95%) for potential reuse in terms of energy. The fabrication of the pilot scale system includes the scale up of a laboratory setup separating CO2 from binary CH4-CO2 gas mixture. After the stability tests of the process, for the operation of 5 months (February to June 2023) the purity and recovery of CH4 in the final gas product. The experimental results showed an average recovery of CH4 of 95.7% for an average 55% feed composition, whereas the average purity in the final product was equal to 82.4%. The purity results were lower because of the N2 presence in the product stream (average 17.5%). After normalization with the help of the lab-scale binary results, the expected results assuming N2 absence would be 99.8% CH4 purity and 67% CH4 recovery. Finally, 3 different membrane configurations are compared in terms of their energy production, concluding to the efficiency of 2-stage configuration with recycling stream for the optimal combination of theoretical stage cut fractions.


Subject(s)
Biofuels , Carbon Dioxide , Anaerobiosis , Bioreactors , Methane
6.
Data Brief ; 52: 109798, 2024 Feb.
Article in English | MEDLINE | ID: mdl-38076480

ABSTRACT

The data reported here was prepared to study the effects of calendering process on NMC622 cathodes using a 3-3-2 full factorial design of experiments. The data set consists of 18 unique combinations of calender roll temperature (85 °C, 120 °C, or 145 °C), electrode porosity (30%, 35%, or 40%), and electrode mass loading (120 g/m² or 180 g/m²). The reported physical characteristics of the electrodes include thickness, coating weight, maximum tensile strength, and density. The electrochemical performances of the electrodes were obtained by testing coin cells. In this context, 54 half-cells were produced, 3 per each calendering experiment to ensure repeatability and reliability of the results. The responses of interest included, charge energy capacity at C/2, C/5, discharge energy capacity at C/20, C/5, C/2, C, 2C, 5C, 10C, gravimetric capacity (charge at C/2, C/5, discharge at C/20, C/5, C/2, C, 2C, 5C, 10C), volumetric capacity (charge at C/2, C/5, discharge at C/20, C/5, C/2, C, 2C, 5C, 10C), rate performance (5C:0.2C), area specific impedance (at 10% to 90% state of charge (SoC) in 10 breakpoints), long-term cycling capacity (charge at C/5 for 50 cycles, discharge at C/2 for 50 cycles), long-term cycling degradation (at C/2 during 50 cycles of charge and discharge), and cycling columbic efficiency (50 cycles of C/2 charge and discharge). The details of the experimental design that has led to this data as well as comprehensive statistical analysis, and machine learning-based models can be found in the recently published manuscripts by Hidalgo et al. and Faraji-Niri et al. [1,2].

7.
Chemosphere ; 341: 139978, 2023 Nov.
Article in English | MEDLINE | ID: mdl-37660793

ABSTRACT

Simultaneous contaminants of emerging concern (CECs) removal and wild microorganisms' inactivation was evaluated by applying solar photoelectro-Fenton (SPEF) process in actual secondary effluent collected from a real municipal wastewater treatment plant (MWWTP). 20 L of a mixture of four CECs was used as model pollutants (200 µg/L of acetaminophen, caffeine, sulfamethazine, and sulfamethoxazole each one). The SPEF process was carried out on fully sunny days, at circumneutral pH using the complex Fe3+-EDDS, in a solar electrochemical - raceway pond reactor (SEC-RPR). Initially, the optimal conditions for CECs degradation were determined using a response surface model based on current density, iron complex concentration and Fe3+-EDDS addition time (to allow previous accumulation of H2O2) as model inputs. A current density of 24.6 mA/cm2, a Fe3+-EDDS complex concentration of 0.089 mM and 3.8 min of previous H2O2 accumulation were the resulting optimum conditions that were afterwards applied for the simultaneous degradation of the CECs synthetic mixture and wild microorganisms inactivation in actual secondary effluent. About 85% CECs removal and complete E. coli inactivation were achieved in 30 min, approximately, while E. faecalis and total coliforms could be inactivated under detection limit in 60 min and 75 min, respectively.


Subject(s)
Disinfection , Escherichia coli , Hydrogen Peroxide , Acetaminophen , Hydrogen-Ion Concentration
8.
Bioresour Technol ; 387: 129571, 2023 Nov.
Article in English | MEDLINE | ID: mdl-37506935

ABSTRACT

The high levels of free ammonia (FA) challenge the application of partial nitritation (PN) and denitrification (DN) in the treatment of ammonia-rich wastewater. This study explored the impact of high levels of FA on the PN and DN stability and microbial community dynamics. By reducing reflux and increasing influent load, the concentrations of FA in PN and DN reactors increased from 28.9 mg/L and 140.0 mg/L to 1099.8 mg/L and 868.4 mg/L, respectively. During this process, the performance of PN and DN remained stable. The microbial analysis revealed that the Nitrosomonas exhibited strong tolerance to high levels of FA, and its relative abundance was positively correlated with amoABC (R2 0.984) and hao (R2 0.999) genes. The increase in microbial diversity could enhance the resistance ability of PN against the FA impact. In contrast, high levels of FA had scant influence on the microbial community and performance of DN.


Subject(s)
Microbiota , Water Pollutants, Chemical , Ammonia , Denitrification , Bioreactors , Nitrogen
9.
Materials (Basel) ; 16(9)2023 May 08.
Article in English | MEDLINE | ID: mdl-37176474

ABSTRACT

This study aims to improve the economic efficiency of the pitch synthesis reaction on the pilot plant by optimizing the pitch synthesis reaction and utilization of the byproduct. The pitch was synthesized using a 150 L pilot plant with pyrolyzed fuel oil as a precursor. The pitch synthesis reaction is carried out through volatilization and polycondensation, which occur at 300 and 400 °C. Volatilization is terminated during heating; thus, additional soaking time is meaningless and reduces the process efficiency. Soaking time is a major variable when the synthesis temperature exceeds 400 °C. The byproduct is generated through volatilization; thus, its chemical characteristics are only influenced by the reaction temperature. The byproduct consists of various polycyclic aromatic hydrocarbons. The average molecular weight and yield of the byproduct increase with the reaction temperature. Carbon black was synthesized using chemical vapor deposition from the byproduct. The particle size of carbon black was controlled by the used precursor (byproduct), and the electrical conductivity of prepared carbon black has a maximum of 58.0 S/cm. Therefore, carbon black, which is synthesized from the byproduct of pitch synthesis, is expected to be used as a precursor for conductive material used in lithium-ion batteries or supercapacitors.

10.
Food Res Int ; 168: 112764, 2023 06.
Article in English | MEDLINE | ID: mdl-37120213

ABSTRACT

Eutectic freeze crystallization is explored as an alternative to the state-of-the-art evaporation process for the recovery of lactose from whey permeate. At the so-called eutectic freezing point, both water (the solvent) and lactose (the solute) crystallize and can be removed continuously while continuously feeding whey permeate. This continuous process is demonstrated on a pilot scale at sub-zero temperatures. In the first instance, only freeze concentration of whey permeate took place at -4 °C. It was possible to reach a lactose concentration of 30 wt% and hardly any nucleation was observed. The resulting ice had high purity, with a lactose concentration of ±2 wt%. Next, the eutectic phase was reached, and lactose and ice crystallized simultaneously and were continuously removed from the system, the resulting crystals had parallelogram morphology with an average size of 10 µm. Ice was recovered at a rate of 60 kg/h and lactose was recovered at a rate of 16 kg/h, yielding over 80% of the feed lactose. A conceptional design was proposed for an improved yield and reduction of energy. Yields of at least 80% and up till 95% could be achieved. Compared to the state-of-the-art mechanical vapor recompression (MVR), EFC is 80% more energy efficient.


Subject(s)
Lactose , Whey , Whey/chemistry , Lactose/chemistry , Freezing , Temperature , Ice/analysis , Crystallization/methods , Whey Proteins/chemistry
11.
Molecules ; 28(3)2023 Jan 25.
Article in English | MEDLINE | ID: mdl-36770837

ABSTRACT

The objective of this work was to evaluate the efficiency of a solar photocatalytic process using g-C3N4 as photocatalyst on the degradation of pharmaceutical compounds detected in hospital wastewater treatment plant secondary effluents. A compound parabolic collector pilot plant, established in the secondary effluent stream of the Ioannina city hospital wastewater treatment plant, was used for the photocatalytic experiments. The analysis of the samples before and after the photocatalytic treatment was accomplished using solid phase extraction (SPE), followed by UHPLC-LTQ/Orbitrap HRMS. Initial effluent characterization revealed the presence of ten pharmaceutical compounds. Among these, amisulpride, O-desmethyl venlafaxine, venlafaxine and carbamazepine were detected in all experiments. Initial concentrations ranged from 73 ng L-1 for citalopram to 2924.53 ng L-1 for O-desmethyl venlafaxine. The evolution of BOD5 and COD values were determined before and after the photocatalytic treatment. All detected pharmaceuticals were removed in percentages higher than 54% at an optimum catalyst loading ranging between 200 and 300 mg L-1. The potential of the catalyst to be reused without any treatment for two consecutive cycles was studied, showing a significant efficiency decrease.


Subject(s)
Waste Disposal, Fluid , Water Pollutants, Chemical , Venlafaxine Hydrochloride , Water Pollutants, Chemical/analysis , Hospitals , Desvenlafaxine Succinate/analysis , Pharmaceutical Preparations
12.
Water Res ; 231: 119610, 2023 Mar 01.
Article in English | MEDLINE | ID: mdl-36680828

ABSTRACT

In high-rate activated sludge (HRAS) processes, reducing the solid retention time (SRT) minimizes COD oxidation and allows to obtain the maximum energy recovery. The aim of this research was to operate a pilot plant with an automatic control strategy to assure the HRAS process stability and high COD fractions removal at very low SRT. This study combines simulation and experimental tools (pilot plant 35 m3·d - 1) operating at SRT (0.2 d), HRT (0.6 h) and DO (0.5 mg·L - 1) treating high-strength raw wastewater, at 18-26°C, at variable flow. The research includes the effects of temperature, influent concentration and MLSS reactor concentration over the sCOD, cCOD and pCOD removal. The study points out that the best parameter to control the HRAS at a low SRT is not strictly the SRT but rather the reactor MLSS concentration: operating at 2,000±200mg·L - 1 assured a stable process despite the large influents variation. Low SVI values of 50-70ml·g - 1 indicated the good settling properties of the biomass. With only a 6.9% COD oxidation, a high organic matter removal (57±9% for COD and 56±10% for BOD5), was reached. The high removal efficiencies for pCOD (74%) compared to the (29%) for sCOD and (12%) for cCOD also confirmed the importance of settling efficiency and stability in the HRAS. The direct correlation between COD influent and COD removal makes advisable to use the HRAS as a replacement of the primary clarifier. The HRAS acted efficiently as a filter for COD and pCOD peak loads and, in a lesser extent, for BOD5, while sCOD peaks were not buffered. The adopted model presented a good fit for COD fractions except for pCOD when the temperature exceeds 23 °C.


Subject(s)
Sewage , Waste Disposal, Fluid , Bioreactors , Wastewater , Temperature
13.
Sci Total Environ ; 870: 161877, 2023 Apr 20.
Article in English | MEDLINE | ID: mdl-36716886

ABSTRACT

Nowadays, the increased consumption of antibiotics, such as metronidazole (MTZ), leads to their introduction in wastewater as well as in the receiving surface waters due to their incomplete removal by conventional wastewater treatment plants. Heterogeneous photocatalysis is a versatile technology that can efficiently degrade such organic contaminants. In the present research, the photocatalytic degradation of MTZ with TiO2 P25 was studied under lab and pilot (CPC reactor) conditions. The antibiotic was efficiently removed at high rates in both cases (100 % and 91 %) following pseudo-first order kinetics with rate constants equal to 0.0452 min-1 (±RSD% = 0.68 % - 2.57 %) and 0.0462 L KJ-1 (±RSD% = 8.94 % - 21.64 %) respectively. Also, by scavenging lab scale experiments, the contribution of the generated reactive species was investigated and hydroxy radicals (HO•) were proposed as the predominant species. By applying high resolution mass spectrometry techniques, the transformation products (TPs) were identified and possible transformation pathways were proposed. The ecotoxicity of the TPs was assessed in silico using the ECOSAR software with the results revealing that most of them were less toxic than the parent compound. Similarly, the mutagenicity, developmental toxicity and bioconcentration factors of the TPs were predicted by utilizing the T.E.S.T. software and in their majority, were found to be less mutagenic and developmentally toxic than MTZ. The ecotoxicity monitoring with the Vibrio fischeri bioassay in both laboratory and pilot scale experiments indicated that through heterogeneous photocatalysis it is possible to reduce the toxicity of wastewater containing MTZ. Finally, the stability and reusability of the photocatalyst was investigated through three consecutive catalytic cycles with the results showing that the performance of TiO2 decreased after each use. For the heterogeneous photocatalysis with TiO2 to be a "real life" applicable technique, further studies focusing on catalyst regeneration and optimization of the catalytic conditions must be conducted.


Subject(s)
Anti-Bacterial Agents , Water Pollutants, Chemical , Metronidazole/analysis , Wastewater , Titanium/chemistry , Catalysis , Water Pollutants, Chemical/analysis
14.
Foods ; 11(23)2022 Nov 23.
Article in English | MEDLINE | ID: mdl-36496583

ABSTRACT

The lack of adequate guidance and control of the extraction conditions as well as the gap between bench- and industrial-scale production, contributes to the poor functionality of commercial pea protein isolate (cPPI). Therefore, pea protein extraction conditions were evaluated and scaled up to maximize protein purity and yield, while maintaining structural integrity, following mild alkaline solubilization with isoelectric precipitation and salt solubilization coupled with membrane filtration. Both extraction methods resulted in high protein yield (>64%) and purity (>87%). Structure-function characterization illustrated the preserved structural integrity of PPI samples and their superior solubility, gelation, and emulsification properties compared to cPPI. Results confirmed, for the first time, that double solubilization at mild pH (7.5) can replace single solubilization at high alkalinity and achieve a similar yield while preserving structural integrity. Additionally, this study demonstrated, the scalability of the benchtop salt extraction coupled with ultrafiltration/diafiltration. Scaling up the production eliminated some structural and functional differences between the salt-extracted PPI and pH-extracted PPI. Scaling-up under mild and controlled conditions resulted in partial denaturation and a low degree of polymerization, coupled with the superior functionality of the produced isolates compared to cPPI. Results of this work can be used as a benchmark to guide the industrial production of functional pea protein ingredients.

15.
HardwareX ; 12: e00362, 2022 Oct.
Article in English | MEDLINE | ID: mdl-36204425

ABSTRACT

Extruders are necessary equipment for 3D filament manufacturing, which is considered a clean technology because it has less scrap and can reuse materials, increasing its life cycle. Open source extruders are less expensive than industrial extruders. However, they have little instrumentation, which limits processing analysis and thus the development of new materials, screw design and process control. Therefore, this project aims to develop a low-cost extruder with a high degree of instrumentation for in-situ process analysis. To achieve this, equipment was developed with an integrated circuit board, both with modularity, machine and peripheral control, process stability, and data acquisition. To validate the equipment, processing was done at constant temperature and with flow variation. The data obtained were the temperatures at different points in the barrel, the rotation speed of the extruder motor, the current consumed by the motor and the resistances, and the speed of the extruder motor. Thermal images of the components were obtained during processing, validating the type of material used in the parts manufactured by additive manufacturing. The ABS filament produced was analyzed by flow and surface analysis using a confocal microscope. Higher flow rates had a better surface quality of the filament.

16.
Bioresour Technol ; 364: 128019, 2022 Nov.
Article in English | MEDLINE | ID: mdl-36162784

ABSTRACT

Despite decades of research and industrial applications of Trichoderma reesei, the development of industrially relevant strains for enzyme production including a low-cost and scalable bioprocess remains elusive. Herein, bioprocess optimization, pilot plant scale-up, techno-economic analysis and life-cycle assessment for enzyme production by an engineered T. reesei strain are reported. The developed bioprocess increased in âˆ¼ 2-fold protein productivity (0.39 g.L-1.h-1) and 1.6-fold FPase activity (196 FPU.L-1.h-1), reducing the fermentation in 4 days. Cultivation in a 65-L pilot plant bioreactor resulted in 54 g.L-1 protein in 7 days, highlighting the robustness and scalability of this bioprocess. Techno-economic analysis indicates an enzyme cost of âˆ¼ 3.2 USD.kg-1, which is below to the target proposed (4.24 USD.kg-1) in the NREL/TP-5100-47764 report, while life-cycle assessment shows a carbon footprint reduction of approximately 50% compared to a typical commercial enzyme. This study provides the fundamental knowledge for the design of economically competitive Trichoderma technologies for industrial use.


Subject(s)
Cellulase , Trichoderma , Animals , Trichoderma/metabolism , Cellulase/metabolism , Bioreactors , Fermentation , Life Cycle Stages
17.
Sci Total Environ ; 849: 157626, 2022 Nov 25.
Article in English | MEDLINE | ID: mdl-35901871

ABSTRACT

The wastewater sector paradigm is shifting from wastewater treatment to resource recovery. In addition, concerns regarding sustainability during the operation have increased. In this sense, many water utilities have become aware of the potential GHG emissions during the operation of wastewater treatment. This study assesses the nitrous oxide and methane emissions during the long-term operation of a novel wastewater resource recovery facility (WRRF) configuration: the mainstream SCEPPHAR. The long-term N2O and CH4 emission factors calculated were in the low range of the literature, 1 % and 0.1 %, respectively, even with high nitrite accumulation in the case of N2O. The dynamics and possible sources of production of these emissions are discussed. Finally, different aeration strategies were implemented to study the impact on the N2O emissions in the nitrifying reactor. Results showed that operating the pilot-plant under different dissolved oxygen concentrations (between 1 and 3 g O2 m-3) did not have an effect on the N2O emission factor. Intermittent aeration was the aeration strategy that most mitigated the N2O emissions in the nitrifying reactor, obtaining a reduction of 40 % compared to the normal operation of the pilot plant.


Subject(s)
Nitrous Oxide , Wastewater , Methane , Nitrites , Nitrous Oxide/analysis , Oxygen/analysis , Wastewater/analysis , Water
18.
Food Res Int ; 156: 111137, 2022 06.
Article in English | MEDLINE | ID: mdl-35651009

ABSTRACT

Esters of 3-monochloro-1,2-propanediol (3-MCPDE), 2-monochloro-1,3-propanediol (2-MCPDE), and glycidyl esters (GE) are processing contaminants that can be found in refined edible fats and oils. Recently, the European Commission has implemented maximum limits for the presence of free and bound 3-MCPDE in vegetable fats and oils and in marine and fish oils. This boosted the necessity of oil producers to develop refining methods to limit the concentration of both 3-MCPDE and GE in their final products. Physical refining may lack the potential to mitigate the formation of 2- and 3-MCPDE. Therefore, in this study, the chemical refining method were explored to provide a viable mitigation strategy aimed at industrial application. Several pilot plant treatments with organic palm oil were performed. The investigated refining methods included a neutralization, a water washing process, reduced deodorization temperature, and a combination of them. The best performing chemical refining treatment achieved a final concentration of 0.42 (-49%), 0.78 (-52%), and 0.99 (-73%) mg/kg for 2-MCPDE, 3-MCPDE, and GE in organic palm oil, respectively. Results thus showed chemical refining has great potential for the simultaneous mitigation of 2-, 3-MCPDE, and GE.


Subject(s)
alpha-Chlorohydrin , Epoxy Compounds , Esters , Glycerol/analogs & derivatives , Palm Oil , Plant Oils , alpha-Chlorohydrin/analogs & derivatives
19.
J Environ Manage ; 317: 115489, 2022 Sep 01.
Article in English | MEDLINE | ID: mdl-35751283

ABSTRACT

The proliferation of industrial-scale CO2 capture technologies requires improvements in existing systems. Absorption/desorption capture processes that employ phase-change solvents (PCS) are promising for energy and cost reduction. Several PCSs have been investigated at bench scale, but very few have been tested in pilot-scale plants. The novel PCS mixture S1N (N1- cyclohexylpropane-1,3-diamine)/DMCA (Dimethylcyclohexylamine) has previously exhibited desirable performance in equilibrium experiments, economic and sustainability studies. This work presents the pilot-scale evaluation of S1N/DMCA for the first time, at two different concentrations and various liquid-to-gas ratios. Experimental evidence on key performance indicators is brought forward, including absorption efficiency, cyclic capacity, distance from equilibrium and regeneration energy in comparison to benchmark solvent MEA (monoethanolamine). S1N/DMCA enables robust operation as it maintains a cyclic capacity of 0.63 mol/kg at different liquid-to-gas ratios, which is about two times higher than that of MEA. It achieves operating loadings close to equilibrium, reaching 1.6 mol/kg, and a regeneration energy of 2.3 GJ/tn CO2, representing 45% reduction compared to MEA.

20.
Bioresour Technol ; 354: 127173, 2022 Jun.
Article in English | MEDLINE | ID: mdl-35452822

ABSTRACT

The biomass of microalgae and cyanobacteria yields a variety of products. Outdoor pilot plant trials typically grow a single species at circumneutral pH and provide CO2 by gas sparging. Here a cyanobacterial consortium was grown at high pH (beyond 11) and high dissolved carbonate concentrations (0.5 M) in an outdoor 1,150 L tubular photobioreactor for 130 days in Calgary, Canada. The aim was to assess the productivity and robustness of the consortium. Importantly, the system was designed to enable future integration of air capture of CO2. Productivity was between 3.1 and 5.8 g ash-free dry weight per square metre per day, depending on biomass density and month. 16S rRNA amplicon sequencing showed that cyanobacterium Candidatus "Phormidium alkaliphilum" made up 80% of the consortium. The consortium displayed robust growth and adapted to environmental conditions. Bicarbonate uptake pushed medium pH past 11, demonstrating the ability to achieve CO2 delivery by air capture.


Subject(s)
Cyanobacteria , Microalgae , Biomass , Carbon Dioxide , Cyanobacteria/genetics , Hydrogen-Ion Concentration , Photobioreactors , RNA, Ribosomal, 16S/genetics
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