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The Davison circulating riser (DCR) is the National Renewable Energy Laboratory's (NREL's) pilot-scale recirculating riser reactor system. Coupled with an upstream fluid-bed pyrolysis system, it permits evaluation of catalytic cracking of biogenic feedstocks, as well as coprocessing of biogenic and fossil feedstocks in a commercially relevant pilot fluid catalytic cracker.
Rapid molecular weight growth of hydrocarbons occurs in flames, in industrial synthesis, and potentially in cold astrochemical environments. A variety of high- and low-temperature chemical mechanisms have been proposed and confirmed, but more facile pathways may be needed to explain observations. Here, we provide laboratory confirmation in a controlled pyrolysis environment of a recently proposed mechanism, radical-radical chain reactions of resonance-stabilized species. The recombination reaction of phenyl (c-C 6 H 5 ) and benzyl (c-C 6 H 5 CH 2 ) radicals produces both diphenylmethane and diphenylmethyl radicals, the concentration of the latter increasing with rising temperature. A second phenyl addition to the product radical forms both triphenylmethane and triphenylmethyl radicals, confirming the propagation of radical-radical chain reactions under the experimental conditions of high temperature (1100-1600 K) and low pressure (~3 kPa). Similar chain reactions may contribute to particle growth in flames, the interstellar medium, and industrial reactors.
Modern proteomics requires reagents for exact quantification of peptides in complex mixtures. Peptide labelling is most typically achieved with isobaric tags that consist of a balancer and a reporter part that separate in the gas phase. An ingenious distribution of stable isotopes offers multiple reagents with identical molecular weight but a different mass of the reporter groups, allowing relative quantification of multiple samples in one measurement. In this work, we discuss a new isobaric labelling reagent, where the balancer and the reporter are linked by a sulfoxide group, which, based on the sulfoxide pyrolysis, leads to easy and asymmetric cleavage at low fragmentation energy. The fragmentation of our new design is significantly improved, yielding more intense complementary ion signals, allowing complementary ion cluster analysis as well.
Drop-in biofuels have been defined as functionally equivalent to petroleum-based transportation fuels and are fully compatible with the existing petroleum infrastructure. They will be essential in sectors such as aviation if we are to achieve emission reduction and climate mitigation goals. Currently, 'conventional' drop-in biofuels, which are primarily based on upgrading of lipids / oleochemicals, are the only significant source of commercial volumes of drop-in biofuels. However, the necessary increased, future volumes will likely come from 'advanced' drop-in biofuels based on biomass feedstocks such as forest and agriculture residues. Biocrudes / bio-oils produced from lignocellulosic feedstocks using thermochemical technologies such as gasification, pyrolysis, and hydrothermal liquefaction need to be further upgraded to drop-in biofuels. However, advanced drop-in biofuels have been slow to reach commercial maturity due to significant technical challenges, high capital costs, and the challenge of generally lower oil prices. It is likely that the co-processing of drop-in biofuels with conventional petroleum refining could considerably reduce capital costs. Initially, co-processing is likely to be established through the upgrading of conventional / oleochemical feedstocks (lipids). Lipids are readily available in large volumes (global production in 2017 was ~185 million metric tonnes) and can be more easily integrated into oil-refinery processes. In contrast, lignocellulose-derived biocrudes / bio-oils are not yet available in significant volumes and are more complex to co-process in a refinery. The likely strategies for co-processing of oleochemicals (lipids) and bio-oil and biocrude feedstocks based on different insertion points within the refinery infrastructure are discussed.
Plastic waste is an emerging environmental issue for our society. Critical action to tackle this problem is to upcycle plastic waste as valuable feedstock. Thermochemical conversion of plastic waste has received growing attention. Although thermochemical conversion is promising for handling mixed plastic waste, it typically occurs at high temperatures (300–800 °C). Catalysts can play a critical role in improving the energy efficiency of thermochemical conversion, promoting targeted reactions, and improving product selectivity. Here this Review aims to summarize the state-of-the-art of catalytic thermochemical conversions of various types of plastic waste. First, general trends and recent development of catalytic thermochemical conversions including pyrolysis, gasification, hydrothermal processes, and chemolysis of plastic waste into fuels, chemicals, and value-added materials were reviewed. Second, the status quo for the commercial implementation of thermochemical conversion of plastic waste was summarized. Finally, the current challenges and future perspectives of catalytic thermochemical conversion of plastic waste including the design of sustainable and robust catalysts were discussed.
We have investigated in this work the physical, optical, electronic, and the magnetic behavior (Curie temperature, magnetic moment) of Zn.1-x.MxO (M = Fe 5%, Co 1%, Cr 5%, and Mn 5%), diluted magnetic semiconductors (DMSs). The samples were deposited on glass substrate by the spray pyrolysis technique, and the results of the x-ray diffraction (XRD) of the prepared substrates was used to prove the incorporation of the dopants into the ZnO lattice host; the ferromagnetic and the antiferromagnetic state competitions and their effects on the physical, magnetic, and optical properties, were investigated. The electronic structure and magnetic properties of transition metal (TM) defects, were investigated in detail, by using the Korringa–Kohn–Rostoker (KKR) method combined with the coherent potential approximation (CPA). As a result, doping by TM impurities induce the ferromagnetism with different competitions between the ferromagnetic and antiferromagnetic states, which affects the physical properties of the TM (Fe, Fe/Co, Cr, and Mn)-doped ZnO, with a Curie temperature closer to room-temperature ferromagnetic.
Herein, we limelight the key features of SnS thin films coated by spray pyrolysis process with different Al doping concentrations. The SnS thin films coated with different Al concentration (0, 2, 4, 6 at wt%) were characterized by various techniques. Structural parameters studied by XRD data revealed that all the prepared films were orthorhombic crystal structure with (111) as a preferential direction. Raman spectroscopy showed the presence of Ag, B{sub 1g}, B{sub 2g}, and B{sub 3g} vibration modes at their corresponding wave numbers. Concentration dependent granular change of Al:SnS films were shown by AFM images. The presence of Sn, S and Al element without any other impurities was confirmed through EDAX picture. UV studies revealed the shrinkage of band gap from 1.97 to 1.72 eV on increasing the Al doping concentration from 0% to 4 at wt%. Room temperature PL showed a high intense red shift, as emission observed at 722 nm for 4% of Al doped SnS thin film. Hall measurements exhibited p-type conducting nature of undoped and Al doped SnS films. The films showed a lowest resistivity of 2.695×10{sup −1} Ω cm for 4 at wt% Al doping concentration. 0.093% efficiency was obtained for the solar cell device fabricated by 4 at wt% of Al doped SnS thin film.
ZnO/MWCNT composite thin films were prepared on glass substrates by spray pyrolysis, and their structural and optical behavior were investigated. X-ray diffraction analysis revealed the films hexagonal wurtzite phase with a preferred (002) growth orientation. Photoluminescence spectra of the ZnO film showed two main bands, a UV emission band at 377 nm (3.28 eV) and a broad blue-yellow band at 439–546 nm with a band at 503 nm. Optical transmittance of 80–85% in the visible range was observed in all the films. In the I–V curves, conductivity was improved when incorporating the MWCNT into the zinc oxide. ZnO/MWCNT, at a value of 2 V and irradiated with visible light presented an increased current from 0.6 to 3.2 nA, and a similar pattern was observed when impinging UV light. Film thickness was measured by profilometry, obtaining thicknesses in the range from 143 to 257 nm.
In this paper, a porous silicon (Psi) surface modification process, including the incorporating of pure and CuO mixed SnO{sub 2} within a Psi layer, was investigated. A Psi layer with a pore-like structure prepared via laser-assisted etching process with a laser illumination intensity of (40) mW/cm{sup 2} was employed as a substrate for materialization SnO{sub 2}/CuO/Psi nanocomposites for gas sensing application. Pure SnO{sub 2} and SnO{sub 2}:CuO nanoparticles were synthesized via a chemical spray pyrolysis process on the Psi surface at 350 °C. The materialization of SnO{sub 2}:CuO/Psi nanocomposites were recognized through Field-Emission Scanning Electron Microscopy, X-ray Diffraction, Atomic Force Microscopy, and Energy-dispersive X-ray Analysis. The results displayed that the morphological properties of SnO{sub 2}:CuO nanoparticles were definitely controlled by varying the CuO contents. Different shapes (nearly cubic shape and spherical shape) with various sizes of SnO{sub 2} and SnO{sub 2}:CuO within the Psi surface were achieved by increasing the CuO content. SnO{sub 2}:CuO/Psi nanocomposites, plans, grain size, average surface roughness, homogeneity and specific surface area of SnO{sub 2}:CuO nanoparticles were considerably influenced by CuO content. The lower grain size and higher average surface roughness and specific surface area were attained when the percentage of CuO was about 30% within the structure of 70% SnO{sub 2}:30% CuO, and the performance of the NH{sub 3} gas sensor revealed a short response time with a high sensitivity of (88%).
Modern agriculture is driving the release of excessive amounts of reactive nitrogen (N) from the soils to the environment, thereby threatening ecological balances and functions. The amendment of soils with biochar has been suggested as a promising solution to regulate the soil N cycle and reduce N effluxes. However, a comprehensive and quantitative understanding of biochar impacts on soil N cycle remains elusive. A meta-analysis was conducted to assess the influence of biochar on different variables involved in soil N cycle using data compiled across 208 peer-reviewed studies. On average, biochar beneficially increases symbiotic biological N2 fixation (63%), improves plant N uptake (11%), reduces soil N2O emissions (32%), and decreases soil N leaching (26%), but it poses a risk of increased soil NH3 volatilization (19%). Biochar-induced increase in soil NH3 volatilization commonly occurs in studies with soils of low buffering capacity (soil pH = 5, organic carbon = 10 g/kg, or clay texture), the application of high alkaline biochar (straw- or manure-derived biochar), or biochar at high application rate (>40 t/ha). Besides, if the pyrolytic syngas is not purified, the biochar production process may be a potential source of N2O and NOx emissions which correspond to 2–4% and 3–24% of the feedstock-N, respectively. This study suggests that to make biochar beneficial for decreasing soil N effluxes, clean advanced pyrolysis technique and adapted use of biochar are of great importance.
For carbothermal reduction (CTR) to be an economic and clean process for magnesium metal production, operational challenges must be overcome. Strong and reactive precursor pellets are necessary to effectively and selectively produce Mg{sub (g)} from any feedstock. In this study, the effects of ore (magnesia and dolime), carbon (petroleum coke, charcoal, algal char, and carbon black), and binder (organic and inorganic) on pellet strength and reactivity, product yield and purity, and reduction selectivity were analyzed. Theoretically and experimentally, the CTR of dolime (MgO·CaO) favored MgO reduction over CaO reduction; however, with enough carbon and heat, both oxides could be reduced. CaO carbothermal reduction produced CaC{sub 2} and Ca{sub (g).} The selectivity to CaC{sub 2} remained constant (7 ± 4 pct) for all C/MgO·CaO ratios analyzed, while the selectivity to Ca{sub (g)} increased (5 pct → 40 pct) when C/MgO·CaO was increased from 0.5 to 2.0. As the overall metal yield decreased (77.6 pct → 59.7 pct) with increasing CaO reduction (38.2 pct → 78.1 pct), Ca{sub (g)} reverted faster than Mg{sub (g).} Heavy metal impurities primarily remained in the residue (< 30 pct volatilized) and, when volatilized, condensed at high temperatures (700 °C to 1450 °C), relative to light metal impurities (350 °C to 1000 °C, > 78 pct volatilized). Organic binders added reducing power to the pellets but produced frail pellets (radial crush strength = 9.1 ± 0.7 N) after pyrolysis, relative to pellets with inorganic binders (15.1 ± 3.2 N). Kinetic parameters were determined for extruded pellets to predict the reaction rate as a continuous function of pressure and temperature.
The state of the interface between slag and carbon determines the slag foaming behavior and thus the effectiveness of carbon in electric arc furnace (EAF) steelmaking. This paper explores the interaction between synthetic slag and carbonaceous materials derived from various sources, including bio-char produced by two different technologies, graphite, coke, and char from tire pyrolysis. Different interfacial phenomena were found between slag and the carbonaceous materials examined. The interactions between bio-char and slag are found to be poor in comparison with other carbonaceous materials. Carbonaceous materials were characterized in terms of their chemical composition and the results obtained suggested that interfacial phenomena were not dominated by ash in the carbonaceous material. The effects of carbon crystalline structure on interaction with slag were evaluated by Raman spectroscopy and X-ray diffraction. Surface properties of the samples were evaluated using scanning electron microscopy, and surface morphology was identified as the principal factor affecting the interaction of slag on carbonaceous particles. The smooth surface of bio-char results in reduced slag foaming. This finding forms the basis for future research on the production of bio-char to be used as a slag foaming agent in EAF steelmaking.
The optimal conditions for preparing composites, in which tar-derived carbonaceous materials completely fill the pores in Indonesian limonite(IL), were investigated using the vapor deposition (VD) method of tar. Characterization of the composites and their reactivity (reduction/combustion/gasification) during heat treatment was examined. The specific surface area and pore volume of the as-received-IL and dehydrated-IL decreased after the VD treatment for different combinations of tar pyrolysis temperature (TPT) and VD temperature (VDT). It was also noted that the carbon content and crushing strength of the samples increased after the VD treatment, and the optimal values for the TPT-VDT are 700 °C and 350 °C. The C content and the crushing strengths of the composites prepared at TPT-VDT = 700 °C to 350 °C increased with an increase of the VD time to 50 pct carbon content and 10 daN at 240 minutes, respectively. The strength was similar to that of commercial metallurgical coke used in blast furnaces. The reduction of the composite prepared at TPT-VDT = 700 °C to 350 °C for 240 minutes started above 400 °C and was almost completed at 1000 °C. This reduction rate was higher than that of commercial cold-bonded pellets or a coke/IL mixture. The combustion and gasification rates of the composites prepared under different conditions depended on the preparation condition of composites, and the rates were higher than those of commercial metallurgical coke used in blast furnaces.
Utilizing pyrolysis chars as the injection fuel in a blast furnace can reduce the dependence on high-quality pulverized coal injection (PCI) coal. In this study, the physical properties and reaction characteristics of chars prepared from two different industrial-scale pyrolyzers (fluidized bed and moving bed) are investigated. The results reveal remarkable component segregation in the char particles with different particle sizes. The properties of large-size char particles are found to better satisfy the PCI fuel requirement in a blast furnace. Compared with PCI coal, the char particles exhibit a rough surface, well-developed pore structure, and less-ordered chemical structure of carbon. Results from isothermal combustion, isothermal gasification, and drop tube furnace experiments show that both types of chars exhibit a better reactivity than PCI coal. The excellent reactivity of chars is closely related to its high Brunauer–Emmett–Teller surface area and relatively poor chemical ordering during conversion. Based on these characteristics, both fluidized bed char (FBC) and moving bed char (MBC) have a great potential to be used as PCI fuels. The application method of chars for PCI in a blast furnace is proposed finally.
A simple design for an open port sampling interface coupled to electrospray ionization (OPSI-ESI) is presented for the analysis of organic aerosols. The design uses minimal modifications to a Bruker electrospray (ESI) emitter to create a continuous flow, self-aspirating open port sampling interface. Considerations are presented for introducing aerosol to the open port sampling interface including aerosol gas flow and solvent flow rates. The device has been demonstrated for use with an aerosol of nicotine as well as aerosol formed in the pyrolysis of biomass. Upon comparison with extractive electrospray ionization (EESI), this device has similar sensitivity with increased reproducibility by nearly a factor of three. The device has the form factor of a standard Bruker/Agilent ESI emitter and can be used without any further instrument modifications. .
Ammonia is well suited to favor deprotonation process in electrospray ionization mass spectrometry (ESI-MS) to increase the formation of [M – H]{sup –}. Nevertheless, NH{sub 3} may react with carbonyl compounds (aldehyde, ketone) and bias the composition description of the investigated sample. This is of significant importance in the study of complex mixture such as oil or bio-oil. To assess the ability of primary amines to form imines with carbonyl compounds during the ESI-MS process, two aldehydes (vanillin and cinnamaldehyde) and two ketones (butyrophenone and trihydroxyacetophenone) have been infused in an ESI source with ammonia and two different amines (aniline and 3-chloronaniline). The (+) ESI-MS analyses have demonstrated the formation of imine whatever the considered carbonyl compound and the used primary amine, the structure of which was extensively studied by tandem mass spectrometry. Thus, it has been established that the addition of ammonia, in the solution infused in an ESI source, may alter the composition description of a complex mixture and leads to misinterpretations due to the formation of imines. Nevertheless, this experimental bias can be used to identify the carbonyl compounds in a pyrolysis bio-oil. As we demonstrated, infusion of the bio-oil with 3-chloroaniline in ESI source leads to specifically derivatized carbonyl compounds. Thanks to their chlorine isotopic pattern and the high mass measurement accuracy, (+) ESI Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) unambiguously highlighted them from the numerous C{sub x}H{sub y}O{sub z} bio-oil components. These results offer a new perspective into the detailed molecular structure of complex mixtures such as bio-oils. .
Methanesulfonic acid (MSA) exhibits several advantageous properties rendering it a promising candidate for circular hydrometallurgical processes. These properties include a high acidity (pKa = - 1.9) comparable to that of classical mineral acids as well as biodegradability, high stability, and high solubility of metal-MSA complexes in aqueous solutions. In this study, MSA was employed as a lixiviant for the leaching of metals (lithium, nickel, cobalt, and manganese) from the black mass of spent lithium-ion batteries (LIBs). The effect of various parameters, including MSA concentration, H 2 O 2 concentration, temperature, and pulp density, was systematically investigated. Under the optimized conditions (1.5 M MSA, 0.2 M H 2 O 2 , 60 °C, and 50 g/L pulp density), quantitative leaching of lithium was achieved within 30 min, while for nickel and cobalt it was after 2 h, and 4 h for manganese leaching. The leaching kinetics of Li, Ni, Co, and Mn were studies using the shrinking particle models (SPM) and the Avrami model. The results indicated that the Avrami model provided the best fit to the kinetic data, with apparent activation energies of 46.81 kJ/mol for Li, 58.61 kJ/mol for Ni, 59.69 kJ/mol for Co, and 58.86 kJ/mol for Mn, within the temperature range of 25-70 °C (except for Li, which was analyzed in the range of 25-60 °C), consistent with chemical reaction control. Subsequently, residual contaminants in the leaching residue were eliminated through pyrolysis. The quantitative leaching of metals in MSA solution (a green lixiviant), combined with the pyrolytic treatment of leaching residues, represents a circular strategy for the total recovery of valuable components from the black mass of spent LIBs.
Analytical Methods for Biomass Characterization and Conversion is a thorough resource for researchers, students and professors who investigate the use of biomass for fuels, chemicals and products. Advanced analytical chemistry methods and techniques can now provide detailed compositional and chemical measurements of biomass, biomass conversion process streams, intermediates and products. This volume from the Emerging Issues in Analytical Chemistry series brings together the current knowledge on each of these methods, including spectroscopic methods (Fourier Transform Infrared Spectroscopy, Near-infrared Spectroscopy, Solid State Nuclear Magnetic Resonance), pyrolysis (Gas Chromatography/Mass Spectrometry), Liquid Chromatography/High Performance Liquid Chromatography, Liquid Chromatography/Mass Spectrometry, and so on.