Journal of Analytical and Applied Pyrolysis最新文献

The co-pyrolysis of Chlorella vulgaris (CV) and tea oilseed residue (TR) is beneficial for improving the pyrolysis characteristics and bio-oil quality. In this study, the effects of different added amounts (5 %, 10 %, 15 %, and 20 %) of metal-organic frameworks (MOFs) derived catalysts (Cu/C, Co/C, Cu-Co/C) on the co-pyrolysis of CV and TR were investigated using microwave pyrolysis oven. The results showed that the MOFs derived catalysts improved the co-pyrolysis reaction; the maximum average reaction rate (R_v, 0.02466 wt%/s), and the minimum reaction time (T_s, 2900 s) were obtained at 20 % Cu-Co/C. In addition, 15 % Co/C obtained the highest bio-oil yield, which reached 23.26 wt%. In the case of bio-char, the highest yield (29.83 wt%) was obtained at 5 % Cu-Co/C. Finally, GC-MS analysis showed that compared to C1T1 (CV:TR = 1:1), the Cu/C and Cu-Co/C catalysts increased the hydrocarbon content in bio-oil by 7.68 % and 9.68 % respectively, while reducing the contents of phenols and amines, whereas Co/C reduced the ester content of bio-oil by 19.14 %.

Waste liquid crystal display (LCD) panels contain a significant amount of rare precious metal In, and In extraction is also the industry's driving force There are currently many reports on the recovery of In from waste LCD panels, but there are not many on the recovery of organic components from waste LCD panels, particularly polarizing film recovery. Pyrolysis is one of the most promising technologies for organic waste recycling. This work utilized TG, TG-FTIR, and Py-GC/MS to examine the pyrolysis properties and product distribution of the polarizing film. Additionally, a range of kinetic analysis methods and density functional theory calculation were utilized to examine the pyrolysis kinetics and mechanism of the polarizing film. Polarizing film are mainly composed of cellulose triacetate (CTA), triphenyl phosphate (TPHP), polyvinyl alcohol (PVA) and polyacrylate. The results showed that CTA first breaks the glycosidic bond through a synergistic reaction to form an active CTA with a low degree of polymerization, and then forms small molecule compounds such as glucan triacetate analog, methylglyoxal, and allyl benzoate, among others, through free radical reactions. PVA first forms long-chain olefins through a dehydration process, and then short-chain olefins by a free radical reaction. TPHP may merely undergo melting and evaporation rather than undergoing a chemical reaction. Polyacrylate generates esters and aldehydes mainly through free radical reactions. This study provides a theoretical foundation and comprehensive reference for the pyrolysis and recycling of waste LCD panels.

The purpose of this research is to evaluate the effectiveness of pyrolyzed hydrochar functionalized with nitrogen containing deep eutectic solvent (DES) in the absorption of CO₂ under low- and high-pressure conditions. Pyrolyzed hydrochars were synthesized by hydrothermally carbonizing pine at the temperature of 200°C and 260°C, followed by pyrolysis at 600°C. These pyrolyzed hydrochars were impregnated with 3 different nitrogen containing DES namely choline chloride: urea, choline chloride: glycerol, and tetrabutylammonium bromide: glycerol all in 1:2 molar ratio. It was found that the functionalized pyrolyzed hydrochars were enhanced with nitrogen and oxygen functionalities (N-H, C-N, and CO). The results also show a substantial reduction in surface area for the functionalized pyrolyzed hydrochars, ranging from 10.19 to 227.74 m²g⁻¹, compared to the surface areas of pyrolyzed hydrochars of 306–337 m²g⁻¹. On the other hand, an increase in N content up to 38 % was identified after functionalization of pyrolyzed hydrochars. Upon conducting CO₂ uptake at low (0.1–1 bar) and high (2.5–3.5 bar) pressure, the functionalized pyrolyzed hydrochars exhibited an CO₂ uptake of up to 9.5 mmol/g at high pressure, which was attributed to the increased total nitrogen content, enhanced surface functionalities, and available micropore volume. The low-pressure isotherm for functionalized pyrolyzed hydrochars showed Langmuir-type isotherm, suggesting a monolayer adsorption. In contrast, the high-pressure isotherms were better fitted to the Freundlich isotherm, suggesting a multilayer adsorption behavior. It was concluded that the enhanced CO₂ uptake is the result of the combined impact of increased surface functionalities and porosity, which results in improved physical and chemical adsorption mechanisms at the high pressure.

Pyrolysis integrated with KOH activation is the most frequently used and efficient method for microalgae to produce N-doped porous biochar. However, the effects of KOH to the pyrolysis process of microalgae are still unclear. Thus, the pyrolysis behavior, kinetics and the release of volatiles especially the nitrogen-containing components during Chlorella pyrolysis with KOH addition were investigated in this study. Results showed that KOH significantly changed the pyrolysis behavior by lowering the initial decomposition temperature and reducing the weight mean activation energy. KOH reacted with the solid matrix even at room temperature. CO₂ was the dominant gas product, the release of which was postponed by KOH addition. KOH inspired the release of NH₃ to lower temperatures (< 400 °C) while the reverse for HNCO. With the increase of KOH, the formation of hydrocarbons in volatiles shifted to higher temperatures while the yield of acids dramatically reduced and even vanished. The release of nitrogen-containing components was greatly inhibited at 600 °C by converting nitrogen in the feedstock to harmless N₂. This study provided insights into the pyrolysis mechanisms of microalgae over KOH for biochar production and the essential environmental impact during the process.

Chlorinated aromatic hydrocarbons like polychlorinated dibenzo-p-dioxins and -furans (PCDD/F) and polychlorinated biphenyls (PCB) are omnipresent in the environment due to historic production, use, and (unintended) release. Nowadays, their emission and maximum concentration in environmental compartments is strictly regulated. During biochar production, PCDD/F and PCB may be formed and retained on the solid pyrolysis product. Industrial biochars certified, e.g., under the European Biochar Certificate (EBC), exhibit concentrations that were always well below threshold values for soil application and even animal feed. However, this has not been sufficiently tested for chlorine (Cl) rich organic material such as marine biomass or polyvinyl chloride (PVC) contaminated feedstock. Here, we analyzed PCDD/F and PCB contamination in biochars produced at different temperatures from different biomasses with comparatively high Cl contents in the range from 0.2 % to 3.8 % (w/w, seagrass, two types of saltwater macroalgae, tobacco stalks, and PVC contaminated wood). All of the biochars produced showed PCDD/F and PCB contents well below the applicable threshold values given by the EBC (< 20 ng TEQ kg⁻¹ for PCDD/F and < 2×10⁵ ng kg⁻¹ for PCB). The EBC thresholds were undershot by a minimum of factor 1.5 for PCDD/F (mostly factor 20) and by a minimum of factor 90 for PCB. Between 1 and 27 ppb of feedstock Cl were transformed to Cl bound in PCDD/F and PCB in the biochars. No consistent correlation between biomass Cl contents and contents of PCDD/F and PCB were found but higher Cl contents in the feedstock led to a more diverse PCDD/F congener pattern in the biochars. Pyrolysis of PVC-amended wood resulted in consistently higher contamination of PCDD/F and PCB in the biochars compared to pyrolysis of the other biomasses, potentially due to differences in Cl speciation in the feedstocks i.e., Cl in PVC is already covalently bound to an organic carbon backbone. A high contamination in PCDD/F and PCB in biochar was intentionally triggered by separation of pyrogas and biochar in the reactor at < 300 °C to promote condensation of contaminants on the solid product. Between 20 % and 80 % of feedstock Cl was released via the pyrogas, i.e., neutralization of HCl in burnt pyrogas might be necessary when pyrolyzing Cl-rich feedstock in industrial biochar production. Our results indicate that biochars produced from Cl-rich feedstocks with proper biochar production process control are conform with European certification guidelines for PCDD/F and PCB contamination. The results open the opportunity to exploit and valorize so far non-used marine or otherwise Cl enriched biomasses for the production of biochar and carbon sinks.

Understanding the synergistic effect of co-pyrolysis between coal and different plastics is very important to reveal the matching between coal and waste plastics, and the influence of plastics with different structures and properties on the synergistic effect can be recognized based on the composition and distribution of co-pyrolysis products. In this study, the co-pyrolysis of low-rank Naomaohu coal (NMH) with thermoplastic polyethylene (PE), polypropylene (PP), polystyrene (PS), and thermosetting phenol-formaldehyde resin (PF) were carried out in a fixed-bed reactor to investigate the synergistic effect of co-pyrolysis between NMH with different plastics. The results showed that the product distribution of NMH co-pyrolysis with different thermoplastics are similar, showing the highest tar yield, while co-pyrolysis with thermoset PF showed the highest solid yield. The addition of PE and PF to NMH had a positive synergistic effect on the tar yield, with an added value of 3.2 wt% and 2.9 wt%, respectively, which was related to the large overlap interval of the weight-loss temperatures of NMH with PE and PF as exhibited by the TG results. In addition, the co-pyrolysis of NMH with polyolefin plastics PE and PP increased the content of aliphatic hydrocarbons such as alkanes and alkenes in the tar, while the co-pyrolysis with polyaromatic plastics PS and PF significantly increased the aromatic compounds such as aromatics and phenols of the tar. Therefore, suitable plastics can be selected for co-pyrolysis with coal to improve tar yield and tar quality.

In this paper, porous activated carbon is successfully prepared from waste apple pruning branches (PGZ), which demonstrates an ultra-high specific capacity of 505 F g ⁻¹ at a current density of 1 A g ⁻¹ with excellent rate performance (215 F g ⁻¹ at 50 A g⁻¹). The assembled supercapacitor also exhibits excellent specific capacitance of 320 F g ⁻¹ (at 0.5 A g⁻¹) and 160 F g ⁻¹ (at 20 A g⁻¹), with a high energy density of 12.03 Wh kg ⁻¹ at a power density of 250.45 W kg ⁻¹ in 6 M KOH. In 1 M Na₂SO ₄ and 1 M Et₄ NBF₄/AC electrolytes, high energy densities of 18.8 Wh kg ⁻¹ and 44.1 Wh kg ⁻¹ could be achieved. It also exhibits high reversible lithium storage capacity of 636.2 mAh g ⁻¹ at 0.2 C and retains 390 mAh g ⁻¹ after 1000 cycles. Even at 0.8 C, the storage capacity is still as high as 327 mAh g ⁻¹, with 282 mAh g ⁻¹ retained after 1000 cycles. These excellent electrochemical properties are attributed to the hierarchical porous structure of the sample prepared under the optimum conditions. The large pores in the hierarchical structure will lead to high-speed capacitive properties due to their low ion transport resistance while the small mesopore and micropore provide a large electrode and electrolyte interface, which can facilitate charge transfer reaction. These outstanding performances highlights the first example of using waste apple pruning branches as a sustainable source of raw materials for the preparation of high value-added porous carbon materials with multiple energy storage functions.

Hydrothermal upgrading is a promising technology for heavy oil, yet the impact of reservoir conditions on the catalytic effect of catalysts and the pathway are not clear. In this study, the effect of the formation environment on the catalytic upgrading process was investigated through simulating the reservoir conditions (2000 mD permeability, 25 % porosity) for catalytic hydrothermal cracking of heavy oil. Under the hydrothermal upgrading conditions（240 ℃, 24 h, 50 wt%, 0.1 wt% nano-Fe₂O₃）, 9.15 % of the heavy component(5.1 % resin and 4.05 % asphaltene) was converted to light component. The content of hydrocarbons below C17 in the saturated fraction increased from 36.29 % to 59.85 %. The structure of the asphaltene was disrupted resulting in a lower level of asphaltene stacking, and N_C/N_H ratio increased 13.61 % compared to heavy oil. In addition, the reservoir condition with quartz as the supporting medium improved the catalytic ability of iron oxide nanoparticles. When injected into the reservoir medium, nano-size facilitated dispersion on the surface of the proppant and inhibited the aggregation of nanoparticles, which ensured the continuous operation of the active sites on the surface of the catalyst. Electron transfer of Fe²⁺/Fe³⁺ catalyzed the heterolytic cleavage of covalent bonds of H₂O/heavy oil molecules was the mechanism for heavy oil upgrading. These findings demonstrated the feasibility of in-situ upgrading of heavy oil through the use of nano-catalysts under reservoir conditions.

Methane pyrolysis is now considered a promising process for producing clean hydrogen and high-value carbon materials. However, it requires very high temperatures (above 1000 °C) due to the kinetic barriers posed by the stable C-H bond, and the production of carbon presents a significant challenge. While solid catalysts can lower the operational temperatures to some extent, they are hindered by carbon accumulation, which deactivates the catalysts and clogs reactors, thus limiting process scalability. Recently, molten media have emerged as potential catalysts for methane pyrolysis. These media offer numerous advantages, including high thermal conductivity and resistance to deactivation via sintering or coking. Despite these advantages, a comprehensive understanding of how the physical properties and intrinsic catalytic activities of molten media influence methane pyrolysis is lacking. This review addresses this gap by examining the roles of physical properties, mainly surface tension, and catalytic activity in methane conversion and carbon morphology. The analysis of apparent activation energies across various molten media indicates that their physical properties significantly impact methane reactivity, challenging the conventional notion of catalytic activity. In summary, this review explores the synergistic effects of molten media's physical and catalytic properties on methane pyrolysis, highlighting the potential for these systems to revolutionize the process by enhancing efficiency and reducing operational challenges. Understanding these interactions is key to advancing the scalability and applicability of methane pyrolysis technologies for sustainable hydrogen production.