Microwave pyrolysis of polypropylene, and high-density polyethylene, and catalytic gasification of waste coffee pods to hydrogen-rich gas.

Plastic waste poses a critical environmental challenge for the world. The proliferation of waste plastic coffee pods exacerbates this issue. Traditional disposal methods such as incineration and landfills are environmentally unfriendly, necessitating the exploration of alternative management strategies. One promising avenue is the pyrolysis in-line reforming process, which converts plastic waste into hydrogen. However, traditional pyrolysis methods are costly due to inefficiencies and heat losses. To address this, for the first time, our study investigates the use of microwave to enhance the pyrolysis process. We explored microwave pyrolysis for polypropylene (PP), high-density polypropylene (HDPE), and waste coffee pods, with the latter primarily comprising polypropylene. Additionally, catalytic ex-situ pyrolysis of coffee pod pyrolysis over a nickel-based catalyst was investigated to convert the evolved gas into hydrogen. The single-stage microwave pyrolysis results revealed the highest gas yield at 500 °C for HDPE, and 41 % and 58 % (by mass) for waste coffee pods and polypropylene at 700 °C, respectively. Polypropylene exhibited the highest gaseous yield, suggesting its readiness for pyrolytic degradation. Waste coffee pods uniquely produced carbon dioxide and carbon monoxide gases because of the oxygen present in their structure. Catalytic reforming of evolved gas from waste coffee pods using a 5 % nickel loaded activated carbon catalyst, yielded 76 % (by volume) hydrogen at 900 °C. These observed results were supported by elemental balance analysis. These findings highlight that two-stage microwave and catalysis assisted pyrolysis could be a promising method for the efficient management of waste coffee pods, particularly for producing clean energy.

Routine method for the analysis of microplastics in natural and drinking water by pyrolysis coupled to gas chromatography-mass spectrometry.

The presence of microplastics (MPs) in water intended for human consumption represents a growing concern due to their ubiquity in the aquatic environments and the potential adverse effects on human health. In this context, validated and standardized analytical methods are required to minimize uncertainties associated with the determination of MPs in water, especially during the drinking water treatment process. In this study, a simple water sampling and extraction procedure and analysis using pyrolysis with gas chromatography coupled to mass spectrometry (Py-GC-MS) was developed to determine 7 types of polymers in water. Quality parameters associated with the method were evaluated, including limits of detection (MDL) and quantitation (MQL), linearity, precision, accuracy, and extended uncertainty. The developed methodology was validated by participating in the EUROQCHARM interlaboratory exercise, and the Z-scores were within the acceptable range for 4 of the 5 polymers tested. Finally, MPs were determined in river water, reclaimed water, and drinking water from the urban area of Barcelona and total concentrations ranged from 11.3 µg/L to 77.1 µg/L. The proposed methodology allows for simple (direct filtration of 100-500 mL of water with a 13 mm glass fiber filter), quantitative (µg/L), and rapid (with a total analysis time of 20 min per sample, including both pyrolysis and GC-MS) analysis of MPs in water intended for drinking.

Selective recovery of pyrolyzates of biodegradable (PLA, PHBH) and common plastics (HDPE, PP, PS) during co-pyrolysis under slow heating.

Pyrolytic synergistic interactions, in which the production of pyrolyzates is enhanced or inhibited, commonly occur during the co-pyrolysis of different polymeric materials, such as plastics and biomass. Although these interactions can increase the yield of desired pyrolysis products under controlled degradation conditions, the desired compounds must be separated from complex pyrolyzates and further purified. To balance these dual effects, this study was aimed at examining pyrolytic synergistic interactions during slow heating co-pyrolysis of biodegradable plastics including polylactic acid (PLA) and poly(3-hydroxybutyrate-co-3-hydroxyhexaoate) (PHBH) and petroleum-based plastics including high-density polyethylene (HDPE), polypropylene (PP), and polystyrene (PS). Comprehensive investigations based on thermogravimetric analysis, pyrolysis-gas chromatography/mass spectrometry, and evolved gas analysis-mass spectrometry revealed that PLA and PHBH decompose at lower temperatures (273-378 °C) than HDPE, PP, and PS (386-499 °C), with each polymer undergoing independent decomposition without any pyrolytic interactions. Thus, the independent pyrolysis of biodegradable plastics, such as PLA and PHBH, with common plastics, such as HDPE, PP, and PS, can theoretically be realized through temperature control, enabling the selective recovery of their pyrolyzates in different temperature ranges. Thus, pyrolytic approaches can facilitate the treatment of mixed biodegradable and common plastics.

Py-GC-MS analysis for microplastics: Unlocking matrix challenges and sample recovery when analyzing wastewater for polypropylene and polystyrene.

Matrix interference and recovery when using pyrolysis gas chromatography (Py-GC-MS) to analyze wastewater for polystyrene (PS) and polypropylene (PP) microplastics (MP) was studied. Raw wastewater underwent a sample preparation train commonly applied for such matrix. The train consisted of six discrete steps to reduce the organic matter content without affecting MP in the sample. One large wastewater sample was collected, homogenized, and subdivided into 21 subsamples. Three samples were analyzed without further sample preparation. The remaining samples were divided in sets of three, and each set underwent an increasing number of steps of the procedure, up to the last set, which underwent the full treatment. The matrix effect on the determination of PS and PP was statistically evaluated by comparing in-matrix and external calibration curves at each step. Recovery of MP was assessed after each step by adding deuterated PS to the samples. A main finding was that there was no significant matrix effect for these polymers throughout the preparation train, suggesting that matrix components did not interfere with the analytical method. However, a significant loss of polymer mass was found between the steps, which may result in MPs falling below detection limits. Therefore, Py-GC-MS could be used for MP quantification before analysis by other techniques which require more extensive matrix removal. A downside of this approach is that analyzing such samples without matrix reduction will increase the need for instrumental maintenance.

Investigating a new approach for magnetic ionic liquids: Dispersive liquid-liquid microextraction coupled to pyrolysis gas-chromatography-mass spectrometry to determine flame retardants in sewage sludge samples.

This study addresses the analysis of emerging contaminants, often using chromatographic techniques coupled to mass spectrometry. However, sample preparation is often required prior to instrumental analysis, and dispersive liquid-liquid microextraction (DLLME) is a viable strategy in this context. DLLME stands out for its ability to reduce sample and solvent volumes. Notably, dispersive liquid-liquid microextraction using magnetic ionic liquids (MILs) has gained relevance due to the incorporation of paramagnetic components in the chemical structure, thereby eliminating the centrifugation step. A pyrolizer was selected in this work to introduce sample onto the GC column, since the MIL is extremely viscous and incompatible with direct introduction through an autosampler. This study is the first to report the use of a DLLME/MIL technique for sample introduction through a pyrolizer in gas chromatography coupled to mass spectrometry (GC-MS). This approach enables the MIL to be compatible with gas chromatography systems, resulting in optimized analytical and instrument performance. The analysis of polybrominated diphenyl ether flame retardants (PBDEs) was focused on the PBDE congeners 28, 47, 99, 100, and 153 in sewage sludge samples. The [P6,6,6,14+]2[MnCl42-] MIL was thoroughly characterized using UV-Vis, Fourier transform infrared spectroscopy (FTIR), and Raman spectroscopy, as well as thermal analysis. In the chromatographic method, a pyrolyzer was used in the sample introduction step (Py-GC-MS), and critical injection settings were optimized using multivariate approaches. Optimized conditions were achieved with a temperature of 220 °C, a pyrolysis time of 0.60 min, and an injection volume of 9.00 µL. DLLME optimization was performed through central compound planning (CCD), and optimized training conditions were achieved with 10.0 mg of MIL, 3.00 µL of acetonitrile (ACN) as dispersive solvent, extraction time of 60 s, and volume of a sample of 8.50 mL. Precision was observed to range from 0.11 % to 12.5 %, with limits of detection (LOD) of 44.4 µg L-1 for PBDE 28, 16.9 µg L-1 for PBDE 47 and PBDE 99, 33.0 µg L-1 for PBDE 100 and 375 µg L-1 for PBDE 153. PBDE 28 was identified and analyzed in the sludge sample at a concentration of 800 µg L-1. The use of MIL in dispersive liquid-liquid microextraction combined with pyrolysis gas chromatography-mass spectrometry enables identification and quantification of PBDEs in sewage sludge samples at concentrations down to the µg L-1 level.

Walnut shell oil-bath torrefaction coupled with fast pyrolysis: Effect of torrefaction heating modes.

Lignocellulosic biomass, renewable with short growth cycle and diverse sources, can be substituted fossil fuel. However, low effective hydrogen-to-carbon ratio (H/Ceff) limits its applications. Torrefaction and co-pyrolysis with high H/Ceff feedstocks are promising technology. This paper investigated the effect of heating modes on oil-bath torrefaction of walnut shells, followed by fast co-pyrolysis. Six heating modes during oil-bath torrefaction were evaluated. Com1 (Microwave 67 %, Lightwave 33 %) yielded the lowest residual yield 84 wt%, while the highest gas production 495.47 mL/g which mainly composed of CO and CO2. Torrefied feedstock under Com1 had the highest H/Ceff. Decarboxylation and decarbonylation reactions dominated among oil-bath torrefaction. Com1 produced the most hydrocarbons and least oxygen-containing compounds. As microwave ratio decreased, the content of olefins, acids and phenols decreased, monocyclic aromatic hydrocarbons and alcohols was showed opposite tend. This study offers new ideas for microwave and lightwave torrefaction and promoting hydrocarbon production from lignocellulosic biomass.

Catalytic pyrolysis of fish waste oil using ZSM-5 catalyst for the production of renewable biofuel.

This present study enlightens the eco-friendly green synthesis of ZSM-5 from natural clay montmorillonite, and its proper incorporation with 'Ni'. Nickle (Ni) was wet impregnated onto HZSM-5 and the resulting catalyst was characterized by various techniques including XRD, BET, N2 Sorption Studies, TPD, SEM and TEM techniques. The SEM images revealed the uniform distribution of Ni over HZSM-5 zeolite catalyst and the XRD results indicated the undistorted crystalline structure of HZSM-5 even after impregnation of Ni. The latter part of the work concentrates on the strength of the catalyst in cracking oil derived from discarded fish parts. Discarded fish waste was pyrolyzed to obtain the fish oil, which was then used for cracking studies. The fish oil was efficiently converted (99% conversion) by Ni/ZSM5 (50 wt %) and yielded 70% liquid fractions, which formed gasoline (78.6%), kerosene (12.3%) and diesel (9.1%). The research is a complete parcel to examine the working potential of the produced biofuel in pre-existing engines. The quality of gasoline fraction was tested according to ASTM standards, which showed that the heating value was slightly lower compared to fossil gasoline. The torque and brake fuel consumption were also examined and it indicated that the fish oil derived gasoline fuel may need to be mixed with the commercial gasoline to optimize its performance.

Continuous rotary kiln pyrolysis of cassava plant shoot system and wide speciation of oxygenated and nitrogen-containing compounds in bio-oil by HESI and APPI-Orbitrap MS.

This work proposes the pyrolysis of the cassava plant shoot system biomass and a comprehensive chemical characterization of the resulting bio-oil. The highest yields of liquid products were obtained at 600 °C, with 12.6 % bio-oil (organic fraction), which presented the lowest total acid number of 65.7 mg KOH g-1. The bio-oil produced at 500 °C exhibited the highest total phenolic content of approximately 41 % GAE, confirmed by GC/MS analysis (33.8 % of the total area). FT-Orbitrap MS analysis found hundreds of oxygenated constituents in the bio-oils, belonging to the O2-7 classes, as well as nitrogen compounds from the Ny and OxNy classes. Higher pyrolysis temperatures resulted in more oxygenated phenolics (O4-7) undergoing secondary degradation and deoxygenation reactions, generating O2-3 compounds. Additional classes affected were O3-5N2-3, while O1-2N1 presented more stable compounds. These findings show that cassava bio-oils are promising sources of renewable chemicals.

Forecasting vaping health risks through neural network model prediction of flavour pyrolysis reactions.

Vaping involves the heating of chemical solutions (e-liquids) to high temperatures prior to lung inhalation. A risk exists that these chemicals undergo thermal decomposition to new chemical entities, the composition and health implications of which are largely unknown. To address this concern, a graph-convolutional neural network (NN) model was used to predict pyrolysis reactivity of 180 e-liquid chemical flavours. The output of this supervised machine learning approach was a dataset of probability ranked pyrolysis transformations and their associated 7307 products. To refine this dataset, the molecular weight of each NN predicted product was automatically correlated with experimental mass spectrometry (MS) fragmentation data for each flavour chemical. This blending of deep learning methods with experimental MS data identified 1169 molecular weight matches that prioritized these compounds for further analysis. The average number of discrete matches per flavour between NN predictions and MS fragmentation was 6.4 with 92.8% of flavours having at least one match. Globally harmonized system classifications for NN/MS matches were extracted from PubChem, revealing that 127 acute toxic, 153 health hazard and 225 irritant classifications were predicted. This approach may reveal the longer-term health risks of vaping in advance of clinical diseases emerging in the general population.

Oil recovery from microwave co-pyrolysis of polystyrene and polypropylene plastic particles for pollution mitigation.

Addressing the mounting environmental challenge of non-degradable polymeric waste, the world grapples with escalating production driven by population growth, modernization, and industrialization. Pyrolysis has emerged as a promising and strategic solution for transforming non-degradable polymeric waste into valuable fuels and other chemical products. This study detailed the high-quality oil recovery from microwave co-pyrolysis of polystyrene (PS) and polypropylene (PP) mixtures. The effects of PS/PP ratio (30:0, 10:20, 15:15, 20:10, and 30:0 g), microwave power (400, 500, 600, 700, and 800 W), and pyrolysis temperature (450, 500, 550, 600, and 650 °C) on oil yield and components were studied, and the synergistic effect, higher heating value (HHV) and thermal efficiency were also detailed. The results revealed that the highest oil yield was 93.84 wt% when PS/PP ratio, microwave power, and pyrolysis temperature were adjusted at 20:10 g, 600 W, and 550 °C, respectively. And the maximum higher heating value and thermal efficiency were 45.67 MJ/kg and 56.53%, respectively. The contents of aromatic hydrocarbons, cyclic hydrocarbons, and oxygenated hydrocarbons varied in the ranges of 1.92-58.88 area%, 10.47-41.76 area%, and 5.06-24.36 area%, respectively. The contents of the major carbon numbers were C8 and C9, and they varied in 2.51-43.66 area% and 7.31-20.09 area%, respectively. The results presented in this study showed that high-quality oil can be recovered from polystyrene and polypropylene plastics by using microwave irradiation, contributing to cleaner ways for plastics recycling.

Se-Pair Search for Deciphering Selenium-Encoded Peptide and a Pyrolysis-Thermolysis Dietary Model for Minimizing Loss of "KKSe(M)R" during Processing.

Dietary deficiency of selenium is a global health hazard. Supplementation of organic selenopeptides via food crops is a relatively safe approach. Selenopeptides with heterogeneous selenium-encoded isotopes or a poorly fragmented peptide backbone remain unidentified in site-specific selenoproteomic analysis. Herein, we developed the Se-Pair Search, a UniProtKB-FASTA-independent peptide-matching strategy, exploiting the fragmentation patterns of shared peptide backbones in selenopeptides to optimize spectral interpretation, along with developing new selenosite assignment schemes (steps 1-3) to standardize selenium-localization data reporting for the selenoproteome community and thereby facilitating the discovery of unexpected selenopeptides. Using selenium-biofortified rice under cooking, fermentation, and high-temperature and high-pressure processing conditions as a pyrolysis-thermolysis dietary model, we probed the single-molecule-level kinetic evolution of the novel selenopeptide "KKSe(M)R" with qual-quantitative information on graph-theory-oriented localization calculations, abundance patterns, activation energy, and rate constants at a selenoproteome-wide scale. We ground-truth-annotated thirteen pyrolysis-thermolysis products and inferred four pyrolysis-thermolysis pathways to characterize the formation reactivity of the main intermediate variables of KKSe(M)R and constructed an advanced probe-type ultrasound technique prior to pyrolysis-thermolysis conditions for minimizing loss of KKSe(M)R during processing. Importantly, we reveal the unappreciated pyro-excitation diversion of KKSe(M)R at pyrolysis-thermolysis time and temperature matrices. These findings provide pioneering theoretical guidance for controlling dietary selenium supplementation within the safety thresholds.

Endogenous iron-enriched biochar derived from steel mill wastewater sludge for tetracycline removal: Heavy metals stabilization, adsorption performance and mechanism.

Steel mill wastewater sludge, as an iron-enriched solid waste, was expected to be converted into iron-enriched biochar with acceptable environmental risk by pyrolysis. The purpose of our study was to evaluate the chemical speciation transformation of heavy metals in biochar under various pyrolysis temperatures and its reutilization for tetracycline (TC) removal. The experimental data indicated that pyrolysis temperature was a key factor affecting the heavy metals speciation and bioavailability in biochar, and biochar with pyrolysis temperature at 450 °C was the most feasible for reutilization without potential risk. The endogenous iron-enriched biochar (FSB450) showed highly efficient adsorption towards TC, and its maximum adsorption capacity could reach 240.38 mg g-1, which should be attributed to its excellent mesoporous structure, abundant functional groups and endogenous iron cycling. The endogenous iron was converted to a stable iron oxide crystalline phase (Fe3O4 and MgFe2O4) by pyrolysis, which underwent a valence transition to form a coordination complex with TC by electron shuttling in the FSB450 matrix. The study provides a win-win approach for resource utilization of steel wastewater sludge and treatment of antibiotic contamination in wastewater.

Thermo-catalytic pyrolysis of sewage sludge and techno-economic analysis: The effect of synthetic zeolites and natural sourced catalysts.

This work focuses to the value added utilization of animal sewage sludge into gases, bio-oil and char using synthetic zeolite (ZSM-5 and Y-zeolite) and natural sourced (diatomite, kaolin, perlite) materials as catalysts. Pyrolysis was performed in a one-stage bench-scale reactor at temperatures of 400 and 600 °C. The catalyst was mixed with the raw material before the pyrolysis. Catalysts had a significant effect on the yield of products, because the amount of volatile products was higher in their presence, than without them. In case of kaolin, due to the structural transformation occurring between 500-600 °C, a significant increase in activity was observed in terms of pyrolysis reactions resulting in volatiles. The hydrogen content of the gas products increased significantly at a temperature of 600 °C and in thermo-catalysts pyrolysis. In the presence of catalysts, bio-oil had more favourable properties.

Mechanism of soot and particulate matter formation during high temperature pyrolysis and gasification of waste derived from MSW.

This research investigates the formation mechanism of soot and particulate matter during the pyrolysis and gasification of waste derived from Municipal Solid Waste (MSW) in a laboratory scale drop tube furnace. Compared with CO2 gasification atmosphere, more ultrafine particles (PM0.2, aerodynamic diameter less than 0.2 µm) were generated in N2 atmosphere at 1200℃, which were mainly composed of polycyclic aromatic hydrocarbons (PAHs), graphitic carbonaceous soot and volatile alkali salts. High reaction temperatures promote the formation of hydrocarbon gaseous products and their conversion to PAHs, which ultimately leads to the formation of soot particles. The soot particles generated by waste derived from MSW pyrolysis and gasification both have high specific surface area and well-developed pore structure. Compared with pyrolysis, the soot generated by gasification of waste derived from MSW had smaller size and higher proportion of inorganic components. The higher pyrolysis temperature led to the collapse of the mesoporous structure of submicron particles, resulting in a decrease in total pore volume and an increase in specific surface area. Innovatively, this research provides an explanation for the effect of reaction temperature/ CO2 on the formation pathways and physicochemical properties of soot and fine particulate matter.

Desulfurization and upgrade of pyrolytic oil and gas during waste tires pyrolysis: The role of metal oxides.

Pyrolysis can effectively convert waste tires into high-value products. However, the sulfur-containing compounds in pyrolysis oil and gas would significantly reduce the environmental and economic feasibility of this technology. Here, the desulfurization and upgrade of waste tire pyrolysis oil and gas were performed by adding different metal oxides (Fe2O3, CuO, and CaO). Results showed that Fe2O3 exhibited the highest removal efficiency of 87.7 % for the sulfur-containing gas at 600 °C with an outstanding removal efficiency of 99.5 % for H2S. CuO and CaO were slightly inferior to Fe2O3, with desulfurization efficiencies of 75.9 % and 45.2 % in the gas when added at 5 %. Fe2O3 also demonstrated a notable efficacy in eliminating benzothiophene, the most abundant sulfur compound in pyrolysis oil, with a removal efficiency of 78.1 %. Molecular dynamics simulations and experiments showed that the desulfurization mechanism of Fe2O3 involved the bonding of Fe-S, the breakage of C-S, dehydrogenation and oxygen migration process, which promoted the conversion of Fe2O3 to FeO, FeS and Fe2(SO4)3. Meanwhile, Fe2O3 enhanced the cyclization and dehydrogenation reaction, facilitating the upgrade of oil and gas (monocyclic aromatics to 57.4 % and H2 to 22.3 %). This study may be helpful for the clean and high-value conversion of waste tires.

Optimizing invasive plant biomass valorization: Deep eutectic solvents pre-treatment coupled with ZSM-5 catalyzed fast pyrolysis for superior bio-oil quality.

The primary objective of this study is to explore the application of a deep eutectic solvent, synthesized from lactic acid and choline chloride, in combination with a pre-treatment involving ZSM-5 catalytic fast pyrolysis, aimed at upgrading the quality of bio-oil. Characterization results demonstrate a reduction in lignin content post-treatment, alongside a significant decrease in carboxyls and carbonyls, leading to an increase in the C/O ratio and noticeable enhancement in crystallinity. During catalytic fast pyrolysis experiments, the pre-treatment facilitates the production of oil fractions, achieving yields of 54.53% for total hydrocarbons and 39.99% for aromatics hydrocarbons under optimized conditions. These findings validate the positive influence of the deep eutectic solvent pre-treatment combined with ZSM-5 catalytic fast pyrolysis on the efficient production of bio-oil and high-value chemical derivatives. .

Design expert based optimization of the pyrolysis process for the production of cattle dung bio-oil and properties characterization.

This study aimed to optimize pyrolysis conditions to maximize bio-oil yield from cattle dung, a waste product of livestock practices. Pyrolysis of cattle dung was carried out in batch type reactor. The pyrolysis process was optimized using a central composite design in response surface methodology, with conversion parameters such as pyrolysis temperature, vapor cooling temperature, residence time, and gas flow rate taken into account. The cattle dung bio-oil was analyzed using gas chromatography/mass spectroscopy (GC/MS), an elemental analyzer, a pH probe, and a bomb calorimeter. Furthermore, the ASTM standard procedures were used to determine the bio-fuel characteristics. The optimized conditions were found to be a pyrolysis temperature of 402 °C, a vapor cooling temperature of 2.25 °C, a residence time of 30.72 min, and a gas flow rate of 1.81 l min-1, resulting in a maximum bio-oil yield of 18.9%. According to the findings, the yield of bio-oil was predominantly affected by pyrolysis temperature and vapor cooling temperature. Moreover, the bio-oil that was retrieved was discovered to be similar to conventional liquid fuels in numerous ways.

Fuel properties and incineration behavior of poultry litter blended with sweet sorghum bagasse and pyrolysis oil.

The incineration of poultry litter (PL) effectively reduces the volume of waste in line with the United Nations Sustainable Development Goal of "affordable and clean energy". However, mono-incineration is associated with considerable challenges due to the varying moisture, structural and chemical composition and low energy yield. The aim of the present work was to investigate the influence of sweet sorghum bagasse (SS) and pyrolysis oil (PO) on improving the fuel properties of PL and mitigating ash related burdens during incineration. The different biomass feedstocks were produced by combining PL with SS at 0.0% (T0), 25% (T1), 50% (T2), 75% (T3) and compared with 100% SS (T4). In order to achieve high energy potential and low ash deposition, the parallel samples were additionally mixed with 10% PO to improve the energy value. The experimental results show that increasing the proportion of SS and adding PO to the mixtures increases the volatile matter and decreases the moisture and ash content. The addition of PO also increases the carbon and hydrogen content. The use of SS and PO thus increased the values of the ignitability index and apparently also the flammability by 30.0%-49.4% compared to pure PL. SS and PO shifted the HHV of the starting material from 16.90 to 18.78 MJ kg-1. In addition, SS + PO improved the flame volume and red color intensity of the PL blends based on the image analysis method. However, the presence of SS and PO did not sufficiently improve the ash-related index values, which requires further investigation.

Energy and economic analysis of alternatives for the valorization of hydrogen rich stream produced in the aqueous phase reforming of pyrolysis bio-oil aqueous fraction.

Aqueous phase reforming has been explored for renewable H2 production from waste biomass. Promising results have been reported for pyrolysis bio-oil aqueous fractions (AFB), but economical assessments are needed to determine process feasibility, which requires both energy consumption minimization and optimal H2 valorization. This work compares different alternatives using process simulation and economic evaluation computational tools. Experimental results and a specific thermodynamic model are used to set mass balances. An adequate heat integration allows to reduce the process energy demand, covering the 100 % of the reactor duty. Optimal H2 unit cost is achieved if part of the produced H2 is valorized for energy self-covering and the rest is commercialized. Renewable H2 net production of c.a. 3.3 kgH2/m3 of treated AFB at a preliminary 1-2 €/kg unit cost is estimated, which can be considered as competitive with green H2, even though a case of diluted AFB is considered.

Production of hydrogen-rich fuel gas from waste plastics using continuous plasma pyrolysis reactor.

There is a serious concern about the large amount of accumulated plastic waste all around the world. Synthetic polymers such as polyethylene terephthalate (PET), polypropylene (PP), and polyethylene (HDPE, LDPE) are substantially present in the plastic waste generated. There are various methods reported to minimise such plastics waste with certain limitations. To overcome such limitations the present study have been carried out in which thermal decomposition of plastic waste of PET, PP, HDPE, and LDPE studied using a novel plasma pyrolysis reactor. The major objective of this work is to investigate the viability of the continuous plasma pyrolysis process for the treatment of various plastic wastes with respect to waste volume reduction and production of combustible hydrogen-rich fuel gas. The effect of temperature and feed flow rate on product gas yield, product gas efficiency, solid residue yield, and H2/CO ratio has been evaluated. The experiments have been carried out at different temperatures within the range of 700-1000 °C. Plasma pyrolysis system exhibited combustible hydrogen-rich gas as a product and solid residue. Liquid products have not been observed during plasma pyrolysis, unlike conventional pyrolysis. The reaction mechanism of plastic cracking has been discussed based on literature and products obtained in the present work. The effects of feed flow rate and temperature on exergy efficiency were studied using the response surface method. The mass, energy, and exergy analyses have also been carried out for all the experiments, which are in the range of 0.95-0.99, 0.48 to 0.77, and 0.30 to 0.69, respectively.