Parent Feedstock Research Articles

Characteristics of chars formed during rapid pyrolysis of biomass model components at high temperature

This paper reports char formation and inherent inorganic transformation during rapid pyrolysis of various biomass model components under simulated pulverized fuel (PF) conditions at 1300 °C. A drop-tube furnace with a novel double-tube configuration was deployed to achieve direct determination of char yield. The results show that rapid pyrolysis of xylan and water-washed lignin (W-L) under the conditions results in char yields of 3.4 wt.% and 12.6 wt.%, respectively, while no char was founded during rapid pyrolysis of water-washed cellulose (W-C). After loading K2CO3 into the W-C (i.e. KW-C) and W-L (i.e. KW-L), the char yields increase to 2.1 wt.% and 15.6 wt.%, respectively. The retentions of Na and S are low in chars after pyrolysis. After rapid pyrolysis, W-L and KW-L chars have higher retentions of AAEM species than xylan, W-C and KW-C chars. Micromorphology analysis shows char particles formed after rapid pyrolysis of all biomass components have a cenospheric structure and a rough surface with many bubbles and pores, demonstrating strong melting processes. For xylan and KW-L, the abundant inorganics accelerate char formation with swelling and reduce the extent of particle shrinkage, resulting in char particles with apparent sizes bigger than the parent feedstock particles. Oppositely, for KW-C and W-L that have low contents of inorganic species, the pyrolyzing particles experience significant shrinkage, resulting in formed char particles with apparent sizes that are much smaller than feedstock particles.

Pyrolysis kinetics of hydrochar using distributed activation energy model

AbstractProducing hydrochar from landfill municipal solid wastes (MSW) is a sustainable alternative to existing waste management practices in low‐ and middle‐income countries. In this study, mixed MSW feedstock (sent for landfilling) was subjected to hydrothermal carbonization to produce hydrochars. The hydrochar showing the highest heating value was subjected to pyrolysis at 5, 10, and 20 K min−1 heating rates. Based on the pyrolysis characteristics, a three pseudo‐component‐based distributed activation energy model was employed to describe the pyrolysis kinetics. The activation energy distributions for the three pseudo‐components were 140 ± 8.7 kJ mol−1, 190 ± 1 kJ mol−1 and 175.9 ± 24.9 kJ mol−1, which were able to predict the pyrolysis profile at all heating rates with R2 > 0.999. Differential thermogravimetric profiles of the hydrochar revealed its pyrolytic reactivity to resemble lignocellulosic constituents. Fourier‐transform infrared analysis of the hydrochar showed retention of oxygen‐containing functional groups (associated with lignocellulosic constituents) from the parent feedstock. © 2022 Society of Chemical Industry and John Wiley & Sons, Ltd.

EFFECTS OF SALTS IN BIODIESEL DERIVED CRUDE GLYCEROL ON VANCOMYCIN PRODUCTION FROM AMYCOLATOPSIS ORIENTALIS ATCC® 19795™

Bioconversion of crude glycerol (CG), the primary byproduct in biodiesel generation, is currently of great interest due to its promising potential in producing chemicals of high commercial interest. The efficient use of CG is still limited primarily due to the presence of impurities that may vary in composition based on the parent feedstock, biodiesel generation process, and any recovery/ purification conducted. In this study, laboratory scale fermentation of vancomycin using Amycolatopsis orientalis ATCC® 19795™ was analyzed based on the presence of salts as an impurity in biodiesel derived CG. Results showed that CG as the sole carbon source inhibited the cell growth, but the vancomycin production was approximately the same (158±2 mg L-1) as that of refined glycerol (RG)-based media at varying initial glycerol concentrations studied (5 g L-1 to 40 g L-1). NaCl as an impurity in biodiesel derived CG reduced both the growth yield coefficient (YX/S) and vancomycin formation at high concentrations. Among other salts tested are NaNO3 and KCl. NaNO3 (0.8 g L-1) supplemented media generated a higher YX/S (1.1 g biomass (g glycerol consumed)-1) and a similar vancomycin concentration (193 mg L-1) compared to the media with added NaCl (YX/S of 0.4 g biomass (g glycerol consumed)-1 and a vancomycin concentration of (190 mg L-1)). Relatively, both the YX/S (0.55 g biomass (g glycerol consumed)-1) and vancomycin concentration (135 mg L-1) was reduced in KCl (0.7 g L-1) supplemented media. The results suggest the potential of using CG (with salts i.e., NaCl as impurities) as an excellent low-cost alternative for RG in fermentation of vancomycin using Amycolatopsis orientalis ATCC® 19795™.

Automated Testing and Characterization of Additive Manufacturing (ATCAM)

The sensitivity of additive manufacturing (AM) to the variability of feedstock quality, machine calibration, and accuracy drives the need for frequent characterization of fabricated objects for a robust material process. The constant testing is fiscally and logistically intensive, often requiring coupons that are manufactured and tested in independent facilities. As a step toward integrating testing and characterization into the AM process while reducing cost, we propose the automated testing and characterization of AM (ATCAM). ATCAM is configured for fused deposition modeling (FDM) and introduces the concept of dynamic coupons to generate large quantities of basic AM samples. An in situ actuator is printed on the build surface to deploy coupons through impact, which is sensed by a load cell system utilizing machine learning (ML) to correlate AM data. We test ATCAM’s ability to distinguish the quality of three PLA feedstock at differing price points by generating and comparing 3000 dynamic coupons in 10 repetitions of 100 coupon cycles per material. ATCAM correlated the quality of each feedstock and visualized fatigue of in situ actuators over each testing cycle. Three ML algorithms were then compared, with Gradient Boost regression demonstrating a 71% correlation of dynamic coupons to their parent feedstock and provided confidence for the quality of AM data ATCAM generates.

Proteins in dried distillers' grains with solubles: A review of animal feed value and potential non‐food uses

AbstractDried distillers' grains with solubles (DDGS) are the main byproduct from bioethanol production and are commonly used as livestock feed. This work aims to provide an overview of animal feed value (protein and amino acid profiles and protein fractionation approaches) and potential non‐food uses of DDGS proteins, particularly those from corn, sorghum, and wheat. Crude protein and amino acids (essential and nonessential) composition vary among different DDGS due to the variation in chemical composition of parent feedstock and processing condition. Extraction or fractionation approaches such as physical/mechanical (sieving and winnowing), chemical (ethanol, acid, and alkaline), and enzymatic (protease) treatments have been explored to isolate specific proteins of corn (zein), sorghum (kafirin), and wheat (gluten protein) from respective DDGS. In addition, valorization of DDGS proteins for biomaterials (biodegradable films and bioadhesives) was evaluated. Due to the heterogeneous nature of DDGS, multi‐stream processes with economic and environmental benefits should be taken into consideration before the commercialization of DDGS proteins. This review will benefit future research and development activities on value‐added and more specific utilizations of DDGS.

Photochemistry after fire: Structural transformations of pyrogenic dissolved organic matter elucidated by advanced analytical techniques

Pyrogenic organic matter (pyOM) is the solid residue left after pyrolysis of organic matter, a process occurring in nature during forest fires. Upon rain events, pyrogenic dissolved organic matter (pyDOM) leaches into the rain water and is transferred to the aquatic environment where it has been identified as an important component of the global carbon cycle. Overall, pyDOM consists of highly condensed aromatic compounds (ConAC) and poorly characterized aliphatic molecules. While the ConAC are thought to be persistent in the environment, a large ConAC accumulation that would match the calculated fluxes of pyDOM formation and export has not been observed. Photo-degradation has been identified as a major pyDOM sink, and it can potentially account for the discrepancy in the global mass balance of pyDOM.Photochemistry of pyDOM has been studied to a certain extent, but neither the structural transformation pathways of pyDOM nor how they relate to pyrolysis temperature and parent feedstocks are well understood. In response to this need, we have examined the products after photo-irradiation of pyDOM derived from a temperature series (250, 400, 525, 650 °C) of oak biochars made under controlled laboratory conditions, which can be considered model pyrogenic substances. Ultrahigh resolution mass spectrometry (FT-ICR-MS), one-dimensional 1H NMR, and two-dimensional 1H-1H total correlation spectroscopy (TOCSY) NMR were used to evaluate the compositional changes that occurred with photo-irradiation.In agreement with previous studies, pyDOM aryl groups were the most photo-labile, and alkyl and O-alkyl groups were photo-produced. A new finding is that polysubstituted olefinic moieties of pyDOM were also photo-degraded. Using TOCSY we identified several small molecular weight compounds whose abundances changed non-linearly across the combustion continuum which suggests that different radical processes occur in the different char leachates. Using mass spectrometric data we observed that pyDOM from oak chars made at lower temperatures (250 and 400 °C), as well as pyDOM from a grass char prepared at 650 °C, photo-transformed to a more hydrogenated and oxygenated composition. In contrast, pyDOM from higher temperature char leachates (525 and 650 °C) transformed predominantly into smaller aliphatic compounds. To explain these differences, we propose a photo-transformation mechanism for ConAC which includes oxygenation of ConAC, ring-opening reactions, and sequential decarboxylation yielding small aliphatic N-rich molecules (marine-like composition). These structures could be further polymerized by reactive oxygen species to form straight-chain alkanes if not consumed by microorganisms. Results from these controlled experiments reveal that the extent of photo-transformation appears to be a function of production temperature and parent feedstock. This study enhances our understanding of ConAC and pyDOM, their terrestrial-to-marine transfers, geochemical stability, and eventual fate in sunlit environments. Here we also show the value of structural characterization of pyDOM, and reveal the many unknowns left to be answered for this complex and analytically challenging type of organic matter.

Environmental impacts of biodiesel production from waste spent coffee grounds and its implementation in a compression ignition engine

This study explores the environmental, economic, and technical feasibility of using spent coffee grounds as parent feedstock for biodiesel production. Biodiesel is produced from the spent coffee grounds, and four blends are prepared—B5, B10, B15, and B20. The effects of two extraction solvents (hexane and petroleum ether) on oil yields of the spent coffee grounds are investigated, employing the Soxhlet extraction technique. The properties of any intermediate yield throughout the production process are characterised and adjusted by post processes to ensure the conformity of the final biodiesel product with the standards (ASTM D6751 and ISO EN14214). The major part of the study investigates the effects of blends on tailpipe emissions and performance of a naturally aspirated single-cylinder compression ignition engine. A wide range of engine speeds (1600–3600rpm at 200-rpm increments) has been considered at three engine loads (100, 75, and 50%). The standard diesel fuel is set as a basis for comparison. Results show that the post processes on the extracted oil yielded water content of 0.038%, free fatty acid fraction of 0.41%, and acid number of <2mg KOH/g. The highest oil extraction (14.12%) was obtained over a 45-min extraction time using a hexane solvent. Biodiesel blends produced lower levels of CO2, CO, and HC. Blend B5 showed average reductions of 0.34, 12.5, and 4.23% at full load for the three aforementioned emissions, respectively; B10 reductions were 3.12, 29.85, and 19.14%, respectively. Higher levels of NOx emissions were detected from all blends. At full load, the average NOx increments of B5, B10, B15, and B20 were 0.35, 1.28, 1.8, and 2.3%, respectively. The outstanding environmental and ecological benefits of using the spent coffee grounds as a potential feedstock for biodiesel production are apparent.

Bio-oil yield potential of some tropical woody biomass

Six tropical biomass samples namely: Ogbono wood (Irvingia wombolu), Mango wood (Mangifera indica), Neem wood (Azadiracta indica), Ogbono shell (Irvingia wombolu), Ogirisi wood (Neubouldia laevis) and Tropical Almond wood (Terminalia catappa) were pyrolyzed in a bench scale screw reactor at 450oC. The physicochemical properties of the samples were determined prior to the pyrolysis experiments. The bio-oil and bio-char produced were similarly characterized using standard procedures established by American Standard and Test Methods (ASTM). The highest bio-oil yield of 66 wt% and least bio-oil yield of 53 wt% were obtained from Neem wood and Tropical Almond wood respectively. The characterization results of the products show that even though the moisture content of the bio-oil was quite higher than those of the original feedstock, their higher heating values were higher than those of the parent feedstock. Both characterization results show that the feedstock and their fast pyrolysis products are good materials for bioenergy production. The Gas Chromatography Mass Spectroscopy (GC-MS) analysis of the bio-oil shows the presence of useful chemicals such as phenols and levoglucosan, which could be harnessed for industrial applications.

Thermal cracking of Athabasca VR and bitumen and their maltene fraction in a closed reactor system

Thermal cracking of Athabasca vacuum residue (AVR) and Athabasca bitumen (AB) and their maltene fraction was investigated at 400°C in a closed system, i.e. autoclave. The effect of the following variables on the product yield and the properties of the liquid fraction and its maltene extract was evaluated: residence time, pressure of the reactor unit, stirring, temperature and asphaltenes content of the feedstock. The yield of the different fractions, the total energy consumption, the pressure buildup in the batch reactor and the °API gravity and viscosity of the liquid fraction and its maltene extract were used to evaluate the impact of a given parameter. In addition, high-temperature simulated distillation (HTSD) analysis of the liquid product and gas chromatography (GC) analysis for gas product were performed. The effect of reaction time, mixing and pressure on the yield of toluene insolubles (TI) depended on the presence of asphaltenes in the feedstock. TI yield increased at the expense of the asphaltenic fraction when reaction time, mixing and pressure increased. There is an inverse relationship between the initial asphaltenes content in the feedstock and the overall asphaltenes yield base on the parent feedstock. Moreover, increasing asphaltenes content of the feedstock did not introduce significant changes in the total energy input to the reactor.

A study on the structural features of the water-insoluble fraction (WIF) isolated from biomass slow steam pyrolysis liquids

This work focuses on the isolation and characterization of the water-insoluble fraction (WIF) of liquids obtained from biomass pyrolysis. This fraction, usually referred to as pyrolytic lignin, contributes significantly to the viscosity, reactivity and instability of the pyrolysis liquids. The WIF isolated from pyrolysis liquid produced by the slow steam-assisted pyrolysis of A. donax canes was compared to the WIFs isolated from pyrolysis liquids of model biomass single components (cellulose, xylan and lignin). The WIFs were characterized by gas chromatography-mass spectrometry, thermogravimetry, infrared spectroscopy and photoionization mass spectrometry coupled with an ion trap analyzer. Overall the data allowed to define the structure of the WIF most abundant components and to relate the WIF composition to the structure of the parent feedstock. Evidence for synergistic effects among the components was also found in real biomass suggesting that biomass acts differently than the sum of its main components.

Biochar persistence, priming and microbial responses to pyrolysis temperature series

Biochar and its properties can be significantly altered according to how it is produced, and this has ramifications towards how biochar behaves once added to soil. We produced biochars from corncob and miscanthus straw via different methods (slow pyrolysis, hydrothermal and flash carbonization) and temperatures to assess how carbon cycling and soil microbial communities were affected. Mineralization of biochar, its parent feedstock, and native soil organic matter were monitored using 13C natural abundance during a 1-year lab incubation. Bacterial and fungal community compositions were studied using T-RFLP and ARISA, respectively. We found that persistent biochar-C with a half-life 60 times higher than the parent feedstock can be achieved at pyrolysis temperatures of as low as 370 °C, with no further gains to be made at higher temperatures. Biochar re-applied to soil previously incubated with our highest temperature biochar mineralized faster than when applied to unamended soil. Positive priming of native SOC was observed for all amendments but subsided by the end of the incubation. Fungal and bacterial community composition of the soil-biochar mixture changed increasingly with the application of biochars produced at higher temperatures as compared to unamended soil. Those changes were significantly (P < 0.005) related to biochar properties (mainly pH and O/C) and thus were correlated to pyrolysis temperature. In conclusion, our results suggest that biochar produced at temperatures as low as 370 °C can be utilized to sequester C in soil for more than 100 years while having less impact on soil microbial activities than high-temperature biochars.

Upgrade of citrus waste as a biofuel via slow pyrolysis

Slow pyrolysis (200–650°C) experiments on citrus residues (orange peel waste “OP” and lemon peel waste “LP”) were carried out in lab scale fixed bed batch reactor. Bio-oil and bio-char obtained by thermal degradation are more stable, more homogeneous and higher energy content fuels when compared to the parent feedstock. Thermogravimetric analysis (TGA) showed higher stability of LP waste, which appears related to the higher lignin content . Mass and energy yields of solid and liquid products (i.e., char and oil) were measured to determine the effects of peak temperature on feedstock. A linear correlation between Gross Calorific Value (GCV), peak temperatures and mass loss (ML) allows easy analytical calculation of energy properties of residues in the range between 200°C and 325°C (peak temperatures). Highest GCV and energy density (ED) of bio-chars are obtained at 500°C peak temperature for both LP and OP residues: EDLP_CHAR=1.70, EDOP_CHAR=1.75. Char reactivities were measured in TGA in a nitrogen atmosphere. High temperature chars (500 and 600°C) showed a higher reactivity than low temperature ones, between 100°C and 400°C. This higher reactivity may be explained by the higher thermal conductivity due to higher ash content and higher surface area of high temperature chars. The tars extracted from pyrolytic bio-oil showed GCVs of approximately 19,700 and 17,000J/g for LP and OP, respectively, independently of pyrolysis peak temperature. Despite the difference in the GCVs, both LP and OP tars show nearly identical FT-IR spectra denoting the presence of very similar chemical species, mainly phenolic, polyaromatics, ketones, ethers and carboxylic acids.

Polyester Fibres in 2012

In 2012, the global polyester (PE) complex yarn and staple fibre production was 43.3 million tons, i.e., 7% higher than in the preceding year, with increased volumes of all major types of products. The increment was the highest in China, USA, Latin America, and Eastern Europe. The production continues to fall perceptibly in Western Europe, Japan, Taiwan, South Korea, and elsewhere. New parent feedstock capacities for PE fibre production are emerging essentially in the Asian region, mainly in China. PE fibre production and consumption in Russia remains extremely low, falling much below the global level on all counts. In spite of staple fibre output growth by 18%, the volumes and quality of this fibre are far from the optimal, and production of textile fibres is very low and of technical fibres is altogether absent. Because of this, import makes a weighty contribution (73%) to the consumption of all types of PE fibres. The outlook for their production growth in the country, judging by the strategy developed for the period until 2030, is so far bleak.

Catalytic conversion of biomass to biofuels

Biomass has received considerable attention as a sustainable feedstock that can replace diminishing fossil fuels for the production of energy, especially for the transportation sector. The overall strategy in the production of hydrocarbon fuels from biomass is (i) to reduce the substantial oxygen content of the parent feedstock to improve energy density and (ii) to create C–C bonds between biomass-derived intermediates to increase the molecular weight of the final hydrocarbon product. We begin this review with a brief overview of first-generation biofuels, specifically bioethanol and biodiesel. We consider the implications of utilizing starchy and triglyceride feedstocks from traditional food crops, and we provide an overview of second-generation technologies to process the major constituents of more abundant lignocellulosic biomass, such as thermochemical routes (gasification, pyrolysis, liquefaction) which directly process whole lignocellulose to upgradeable platforms (e.g., synthesis gas and bio-oil). The primary focus of this review is an overview of catalytic strategies to produce biofuels from aqueous solutions of carbohydrates, which are isolated through biomass pretreatment and hydrolysis. Although hydrolysis-based platforms are associated with higher upstream costs arising from pretreatment and hydrolysis, the aqueous solutions of biomass-derived compounds can be processed selectively to yield hydrocarbons with targeted molecular weights and structures. For example, sugars can be used as reforming feedstocks for the production of renewable hydrogen, or they can be dehydrated to yield furfurals or levulinic acid. For each of the platforms discussed, we have suggested relevant strategies for the formation of C–C bonds, such as aldol condensation of ketones and oligomerization of alkenes, to enable the production of gasoline, jet, and Diesel fuel range hydrocarbons. Finally, we address the importance of hydrogen in biorefining and discuss strategies for managing its consumption to ensure independence from fossil fuels.

CHARACTERIZATION OF CRUDE GLYCEROL FROM BIODIESEL PRODUCTION FROM MULTIPLE FEEDSTOCKS

Glycerol is the principal by-product of biodiesel production. For each gallon of biodiesel produced, approximately0.3 kg of crude glycerol accompanies. Such crude glycerol possesses very low value because of the impurities contained. Asthe demand and production of biodiesel grow exponentially, the utilization of the glycerol becomes an urgent topic. Themake-up of crude glycerol varies depending on the parent feedstock and the biodiesel production process. Before the crudeglycerol could be considered for possible value-added utilizations, it is necessary to characterize it on its physical, chemical,and nutritional properties. This article reports the characterization of crude glycerol obtained from different seed oilfeedstocks of mustard, rapeseed, canola, crambe, soybean, and waste cooking oils. Batch processes of biodiesel productionwere used as the means of crude glycerol preparation using unrefined vegetable oils, methanol, and sodium methylate as thecatalyst. After separation from biodiesel, the crude glycerol from each of the oils was analyzed using ASTM and other standardtest methods. Elemental impurities, nutritional value, and other chemical properties were tested.

Improvement of the thermal stability of lignocellulosic materials by treatment with sulphuric acid and potassium hydroxide

In this study, a lignocellulosic feedstock obtained from Scandinavian pine wood was thermally treated in the presence of sulphuric acid or potassium hydroxide in order to improve its thermal stability. The thermal decomposition of the reaction products was monitored by thermogravimetric analysis and the microstructure of the chars obtained at 900 °C was analysed by optical microscopy. The results show that sulphuric acid and potassium hydroxide transform the lignocellulosic feedstock via different mechanisms of reaction. Sulphuric acid reacts without the incorporation of sulphur, while potassium hydroxide is incorporated into the lignocellulosic feedstock. In both cases, the resultant reaction products are more thermally stable and yield higher residues at 1000 °C than the parent feedstock in thermobalance. Observation by optical microscopy of the chars obtained at 900 °C evidences that sulphuric acid preserves the honeycomb structure of the parent feedstock, while potassium hydroxide yields a reaction product that passes through a fused stage during carbonization.