Feedstock Type Research Articles

Effect of Biochar Type and Amendment Rates on Soil Physicochemical Properties: Potential Application in Bioengineered Structures

Abstract Biochar has recently gained attention as a potential soil amendment for its usage in bioengineered structures, e.g., landfill cover system, green slopes, green corridor, etc., that usually comprises compacted soil with vegetation. In literature, many studies have explored the effect of biochar sourced from plant (agri-residues, wood)- and animal-based biomass on physicochemical properties of soil suitable for agricultural application. However, systematic study rarely has been conducted for soil suitable for bioengineered structures, and contradictory results have been reported. The objective of the present study is to explore the effects of biochar produced from different feedstock types (poultry litter, water hyacinth, and sawdust) on physicochemical properties of soil for bioengineered structures application. The results revealed that the amendment of biochar increased the liquid limit (14–52 %), plastic limit (PL, 2–66 %), optimum moisture content (OMC, 4–50 %), pH (29–59 %), cation exchange capacity (20–428 %), and water absorption capacity (12–94 %), whereas it decreased the maximum dry density (7–17 %), specific gravity (3–17 %), and shrinkage area ratio (SAR, 22–57 %) of the soil. Among the different biochar types tested, water hyacinth biochar (WHB) exhibited the highest increase in PL, OMC, and pH, and decrease in specific gravity and SAR of the soil after amendment, whereas poultry litter biochar showed the lowest variation of the same. These changes in the soil physicochemical properties after biochar amendment are likely attributed to the presence of intrapores and active chemicals in biochar, which are highly dependent on feedstock types. The findings of the present study could be useful in understanding the hydro-mechanical and plant interaction of biochar-amended soil (BAS), and potential implementation of BAS in bioengineered structures.

Life Cycle Assessment of Biofuels using Monte Carlo Simulation

Biofuels are a viable alternative to fossil fuels, providing potential advantages in mitigating greenhouse gas emissions and improving energy security. Nonetheless, the environmental sustainability of biofuels requires thorough evaluation across their whole life cycle. This report provides a thorough Life Cycle Assessment (LCA) of biofuels, emphasizing greenhouse gas emissions, energy use, and resource depletion. Monte Carlo simulation is used to address variability and uncertainty in critical parameters, yielding a reliable assessment of environmental consequences. Findings demonstrate that biofuels may decrease greenhouse gas emissions by 45-60% relative to fossil fuels; however, considerable heterogeneity is seen based on feedstock type, agricultural methods, and conversion technology.

Life Cycle Assessment of Biofuels using Monte Carlo Simulation

Biofuels are a viable alternative to fossil fuels, providing potential advantages in mitigating greenhouse gas emissions and improving energy security. Nonetheless, the environmental sustainability of biofuels requires thorough evaluation across their whole life cycle. This report provides a thorough Life Cycle Assessment (LCA) of biofuels, emphasizing greenhouse gas emissions, energy use, and resource depletion. Monte Carlo simulation is used to address variability and uncertainty in critical parameters, yielding a reliable assessment of environmental consequences. Findings demonstrate that biofuels may decrease greenhouse gas emissions by 45-60% relative to fossil fuels; however, considerable heterogeneity is seen based on feedstock type, agricultural methods, and conversion technology.

Integration of food raw materials, food microbiology, and food additives: systematic research and comprehensive insights into sweet sorghum juice, Clostridium tyrobutyricum TGL-A236 and bio-butyric acid.

Sweet sorghum juice is a typical production feedstock for natural, eco-friendly sweeteners and beverages. Clostridium tyrobutyricum is one of the widely used microorganisms in the food industry, and its principal product, bio-butyric acid is an important food additive. There are no published reports of Clostridium tyrobutyricum producing butyric acid using SSJ as the sole substrate without adding exogenous substances, which could reach a food-additive grade. This study focuses on tailoring a cost-effective, safe, and sustainable process and strategy for their production and application. This study modeled the enzymolysis of non-reducing sugars via the first/second-order kinetics and added food-grade diatomite to the hydrolysate. Qualitative and quantitative analysis were performed using high-performance liquid chromatography, gas chromatography-mass spectrometer, full-scale laser diffraction method, ultra-performance liquid chromatography-tandem mass spectrometry, the cell double-staining assay, transmission electron microscopy, and Oxford nanopore technology sequencing. Quantitative real-time polymerase chain reaction, pathway and process enrichment analysis, and homology modeling were conducted for mutant genes. The treated sweet sorghum juice showed promising results, containing 70.60 g/L glucose and 63.09 g/L fructose, with a sucrose hydrolysis rate of 98.29% and a minimal sucrose loss rate of 0.87%. Furthermore, 99.62% of the colloidal particles and 82.13% of the starch particles were removed, and the concentrations of hazardous substances were effectively reduced. A food microorganism Clostridium tyrobutyricum TGL-A236 with deep utilization value was developed, which showed superior performance by converting 30.65% glucose and 37.22% fructose to 24.1364 g/L bio-butyric acid in a treated sweet sorghum juice (1:1 dilution) fermentation broth. This titer was 2.12 times higher than that of the original strain, with a butyric acid selectivity of 86.36%. Finally, the Genome atlas view, Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and evolutionary genealogy of genes: Non-supervised Orthologous (eggNOG) functional annotations, three-dimensional structure and protein cavity prediction of five non-synonymous variant genes were obtained. This study not only includes a systematic process flow and in-depth elucidation of relevant mechanisms but also provides a new strategy for green processing of food raw materials, improving food microbial performance, and ensuring the safe production of food additives.

Analysis of approaches to the use of intermediate crops as feedstock for biomethane production in Ukraine

The wide use of renewable energy sources, in particular biomass, makes a significant contribution to the decarbonization of the energy and transport sectors. Today, one of the most promising directions for the development of European and Ukrainian bioenergy is the production and consumption of biomethane. Biomethane can be used both, as a direct substitute for natural gas in the production of heat and electricity, and as motor fuel. The priority development of biogas/biomethane production is indicated in the European Green Deal, which the EU has been following since the end of 2019. Special attention is paid to the issues of sustainable development of bioenergy, including the use of sustainable feedstock for obtaining all types of biofuels. Because of this, the new version of the EU Renewable Energy Directive of 2023 (RED III) strengthened the sustainability requirements for the production of liquid biofuels and biogas for transport. One of the sustainable types of feedstocks for the production of biomethane can be biomass of intermediate crops, which are plants that are grown in the time interval free from the cultivation of main crops in the crop rotation. All the mentioned issues are relevant and important for Ukraine as a member of the Energy Community and a potential member of the EU, which will join the implementation of the European Green Deal in the future. The purpose of the work is to assess the potential of biomethane production from intermediate crops in Ukraine and to develop some preliminary recommendations for the development of this sector. The assessment of the potential was carried out using the conservative approach described in the study by experts of Ghent University (Belgium). It is assumed that 20% of the total sown area can be allocated for the cultivation of intermediate crops. The obtained results show that even with a conservative approach, the potential for biomethane production from intermediate crops is the largest component of the total potential for obtaining biomethane from various feedstocks in Ukraine, namely 9.29 billion m3 CH4/y, which is 47% of the total potential. This points to very good prospects for the development of this bioenergy sector in the country. When elaborating preliminary recommendations for the introduction of biomethane production from intermediate crops in Ukraine, main principles of Biogasdoneright, the European model of sustainable agriculture development were taken into account. Ukraine’s natural-climatic and soil-water conditions have been analysed from the viewpoint of possibility and effectiveness of growing intermediate crops for bioenergy. Some types of agricultural crops for sequential cultivation and possible crop rotations have been suggested. The directions of further research, scientific and practical work necessary for the development of this bioenergy sector in Ukraine have been determined.

Unlocking the secrets of porous silicon formation: insights into magnesiothermic reduction mechanism using in situ powder X-ray diffraction studies.

The magnesiothermic reduction of SiO2 is an important reaction as it is a bulk method that produces porous Si for a wide range of applications directly from SiO2. While its main advantage is potential tunability, the reaction behavior and final product properties are heavily dependent on many parameters including feedstock type. However, a complete understanding of the reaction pathway has not yet been achieved. Here, using in situ X-ray diffraction analysis, for the first time, various pathways through which the magnesiothermic reduction reaction proceeds were mapped. Further, the key parameters and conditions that determine which pathways are favored were determined. It was discovered that the reaction onset temperatures can be as low as 348 ± 7 °C, which is significantly lower when compared to previously reported values. The onset temperature is dependent on the size of Mg particles used in the reaction. Further, Mg2Si was identified as a key intermediate rather than a reaction byproduct during the reduction process. Its rate of consumption is determined by the reaction temperature which needs to be >561 °C. These findings can enable process and product optimization of the magnesiothermic reduction process to manufacture and tune porous Si for a range of applications.

Synergetic Effect of Digestate Dissolved Organic Matter and Phosphogypsum Properties on Heavy Metals Immobilization in Soils

The main idea was to justify the natural, technological, and ecological aspects of digestate-based composite for heavy metals (HMs) binding in soil due to organic matter content and mineral additives’ biosorption properties. The study aimed to determine the potential of a composite made from digestate and phosphogypsum for remediation of HMs polluted soils and the role of dissolved organic matter (DOM) in binding HMs. Methods used included a literature review to identify the mechanisms for HM binding to digestate DOM, a laboratory setup for producing a digestate-based composite with digestate (from manure or sewage sludge) mixed with phosphogypsum, and an analysis of digestate fluorescence properties. Results show that a composite based on digestate from manure as feedstock had a higher fluorescence complexity index than a composite with sewage sludge digestate (2.2 and 1.71, respectively). However, the DOM stability in the sewage sludge digestate composite was higher than reported in the literature, probably due to the mineral composition of phosphogypsum, which resulted in a high HMs sorption capacity and its positive effect on soil microbial activity. Based on the theoretical substantiation of DOM content and its binding properties, manure was the most effective feedstock type out of the two tested if digestate was used for HM remediation. Using a digestate-based composite with phosphogypsum can potentially reduce the ecological risk levels imposed by HM-contaminated soils from considerably too low.

Synergizing Sustainability: Recycling Food Waste for Plant Fertilizer Production and Unveiling Ecological Dynamics

Abstract: This research presents a comprehensive investigation into the environmental sustainability of recycling practices, plant health dynamics, soil composition variations, and water quality parameters. Utilizing synthetic data generated through a Google Form, the study explores the intricate relationships among these factors. The first segment focuses on recycling efficiency, employing an independent samples t-test to discern mean differences between 'Kitchen Waste' and 'Sawdust,' followed by a oneway ANOVA that delves into recycling efficiency variations among diverse feedstock types. The second segment elucidates plant variations, employing a one-way ANOVA to uncover patterns in nutrient content across different plant types and a regression analysis to unveil the quantitative relationships between plant characteristics and nutrient content. The third segment scrutinizes soil composition, utilizing a one-way ANOVA to identify significant differences in organic carbon content among various soil types. A cross-tabulation explores the intricate relationships between soil texture and soil type, while a correlation analysis delves into interdependencies among organic carbon, moisture content, water holding capacity, and pH level in the soil. The fourth segment investigates water quality parameters, employing a one-way ANOVA to unveil differences in BOD among distinct water sources and a correlation analysis that provides a holistic exploration of interrelationships among key water quality parameters. The synthesis of these analyses contributes to a nuanced understanding of environmental dynamics, paving the way for informed sustainability practices. The research not only advances our knowledge of individual factors but also provides a holistic perspective on their interplay, offering valuable insights for policymakers, environmental scientists, and practitioners aiming to enhance ecological well-being.

THERMAL SHOCK BEHAVIOR OF LANTHANUM ZIRCONATE-BASED THERMAL BARRIER COATINGS

In this study, La2Zr2O7, Yb2O3 and Gd2O3-doped La[Formula: see text](Gd, Yb)[Formula: see text]Zr2O7 thermal barrier coatings have been manufactured from the crystalline and amorphous feedstock by plasma spraying. The thickness of the bond coat is 100±25 [Formula: see text]m and the thickness of the top coat is 250±25 [Formula: see text]m. Thermal shock tests were carried out in furnace temperature of 1200∘C. The thermal shock tests indicate that lifetime of the La[Formula: see text]Gd[Formula: see text]Zr2O7 coating has 55 cycles which is the highest thermal shock lifetime compared to other coatings in this study. The type of feedstock, amorphous or crystalline, strongly affects the thermal shock lifetime of La2Zr2O7 coatings. Coating damage after thermal shock tests was investigated using scanning electron microscope to observe the microstructure and X-ray diffraction techniques to analyze the phase composition. The failure of coatings is mainly in consequence of the accumulation of stress between bond coat–ceramic coat interface due to thermal expansion coefficient differences and thermally grown oxide layer formation during thermal shock cycling tests.

Study on the Co-gasification characteristics of biomass and municipal solid waste based on machine learning

Co-gasification of biomass and municipal solid waste (MSW) exhibits synergistic effects by improving the quality of syngas while reducing environmental pollution from MSW. In this study, Machine learning (ML) techniques were employed to investigate the co-gasification process of biomass and MSW. A comprehensive dataset was constructed using existing data, including different feedstock types and operating conditions, with 18 input features and 9 output features. Four advanced ML models were utilized to model and analyze the co-gasification process. By leveraging feedstock characteristics and operating parameters, key gasification parameters such as syngas composition, lower heating value (LHV) of syngas, tar yield, and carbon conversion efficiency were predicted. The results showed that all four models exhibited excellent predictive performance, with R2 values greater than 0.9 in both the training and testing stage. Specifically, Histogram-based gradient boosting regression (HGBR) exhibited the lowest root mean square error (RMSE) in predicting CO, while the gradient boosting regressor (GBR) achieved the best performance in H2 prediction with a RMSE of 1.6. The most influential input features for CO concentration were equivalence ratio (ER), oxygen content in biomass and hydrogen content in biomass. The key features affecting H2 concentration were steam/fuel and ER.

THERMOCATALYTIC DESTRUCTION OF HEAVY PETROLEUM FOODS IN THE PRESENCE OF A METAL COMPLEX CATALYST

The oil and gas refining industry in Russia and other countries is faced with the challenge of searching for new highly active catalytic systems and innovative methods for processing various types of petroleum feedstocks, including heavy petroleum feedstocks. One of the main tasks of this industry is to increase the depth of processing of petroleum raw materials to obtain more valuable petrochemical products.The purpose of the work is to study the dependence of the thermal destruction of heavy petroleum feedstock – heavy vacuum gas oil from the AVT-5 unit of PJSC «Bashneft-Novoil» in the presence of a new metal-complex catalytic system, where the active component is a chlorferrate complex (NaFeCl4) in an amount of 10 %, deposited on a carrier representing is a deeply decationized Ymmm zeolite of the acidic form (H-form), when varying process conditions, temperature in the range from 450 to 550 °C and volumetric feed rate of raw materials – 1,75–2,50 h-1. The physicochemical characteristics of the metal complex catalyst – 10 % NaFeCl4 / HYmmm zeolite were studied: characteristics of the porous structure, study of the phase composition, study of the morphology of the surfaces of catalytic systems.During experimental studies, it was established that the 10 % NaFeCl4/HYmmm zeolite catalytic system has a highly developed surface with a pore distribution of micro-, meso- and macropore sizes (total pore volume ~ 0,64 cm3/g); preserves the degree of crystallinity of the lattices relative to the original support Ymmm. It has been established that thermocatalytic destruction of heavy vacuum gas oil in the presence of a metal complex catalyst leads to its deep and selective conversion. The data obtained indicate that in the studied modes of the thermal destruction process, it is possible to achieve the formation of unsaturated olefinic hydrocarbons of the composition C2-C4 ~ 20 % wt., gasoline fraction ~ 45 % wt., total light ~ 68 % wt.

Comparative analysis of biochar carbon stability methods and implications for carbon credits

Biochar is an emerging negative emission technology. Its ability to sequester carbon and subsequent carbon credit valuation hinge on the stability of its carbon structure. The widely used indicators of carbon stability H:Corg and O:Corg provide conservative results as these are based on limited incubation experiments and associated modeling results. The results from these accepted methods and other derived methods have not been compared as indicators of carbon stability in a variety of biochar samples. Furthermore, the influence of contrasting feedstock and production techniques on biochar carbon stability is not well explored. Therefore, to address these challenges, a comprehensive stability analysis of 21 different biochar samples with contrasting feedstocks and pyrolysis techniques was conducted using a combination of instrumental methods and derived indicators of carbon stability. Methods such as biochar carbon half-life, thermo-stable fraction, oxidation resistance (R50), and carbon sequestration potential (CS) were used. Based on the initial carbon content of the biochar, simple pyrolysis techniques have similar potential for carbon credits as biochar produced from advanced pyrolysis techniques. Results indicate that the carbon stability of a biochar product is primarily a factor of feedstock type. We found that biochar carbon stability is not related to volatile matter or fixed carbon content for biochar produced using a simple pyrolysis technique and mixed feedstock. Biochars with H:Corg < 0.4 were deemed to have lower carbon stability when compared using different methods. No correlation was observed between the carbon stability of biochar using H:Corg and other methods, however, correlations were observed between half-life, O:Corg, fixed carbon, number of aromatic peaks in FTIR spectrum, R50, and CS. Therefore, it is recommended that data from additional incubation and modeling studies need to be considered to increase the confidence in carbon stability results having major implications to carbon credits.

(Corrosion Division Rusty Award for Mid-Career Excellence) Enhancing the Corrosion Resistance of Additively Manufactured Metallic Materials: The Role of Feedstock Modification

The properties of metallic materials produced through additive manufacturing (AM), including their corrosion behavior, depend on various parameters such as the type of AM technique, processing parameters, built environment, and the feedstock used [1]. These factors collectively influence the occurrence of processing defects and the microstructure of the alloy, which can be controlled through feedstock modifications. To illustrate the impact of feedstock modification on both microstructure and corrosion, two examples will be presented. These examples will compare the corrosion behavior of additively manufactured 316L stainless steel (SS) produced using three different types of feedstocks: the as-received feedstock, feedstock modified with CrN, and feedstock modified with carbon nanotubes. The feedstock modification was carried out by ball milling of commercial 316L SS powder with the selected additive [2-4]. Test coupons were produced by laser powder bed fusion of the commercial feedstock and modified feedstock. Corrosion resistance was evaluated using cyclic potentiodynamic polarization tests in NaCl solution. The pitting and repassivation potentials of the 316L SS produced by modified feedstock were significantly higher compared to those of 316L SS produced using as-received feedstock [2-4]. The mechanistic aspects of the feedstock modifications and their influence on corrosion behavior will be discussed in detail.1. V.B. Vukkum, R.K. Gupta, Review on Corrosion Performance of Laser Powder-Bed Fusion Printed 316L Stainless Steel: Processing Parameters, Manufacturing Defects, Post-Processing, Feedstock, and Microstructure, Materials & Design, 221, 110874 (2022)2. A. Nieto, V. B. Vukkum, P. Jalagam, K. Nema, J. Budan, R.K. Gupta, T.Y. Ansell, 3D Printed Carbon Nanotube Reinforced Stainless Steel via Selective Laser Melting, MRS Communications 12, 578, 20223. V.B. Vukkum, J. Christudasjustus, A.A. Darwish, S.M. Storck, R.K. Gupta, Enhanced corrosion resistance of additively manufactured stainless steel by modification of feedstock, npj Materials Degradation 6, 1 (2022)4. V.B. Vukkum, F. Ozdemir, S. Storck, R.K. Gupta, Corrosion performance of feedstock modified - Additively manufactured stainless steel. Corrosion Science, 209, 110724 (2022).

Qualitative and quantitative chemometric modelling of nanostructured carbon samples based on infrared spectroscopy

Rapid population growth necessitates a continuous increase in industrial productivity, with a concomitant environmental burden. During the past few years, nanostructured carbon materials have proved their effectiveness in reducing the usage of several hazardous substances, owing to their distinct characteristics. These properties depend on the type of feedstock and the parameters of pyrolysis. We have developed multivariate prediction models to determine several physical properties of nanostructured carbon samples, which are usually calculated from the adsorption isotherms. Adsorption measurement is a time-consuming and exhaustive process. Therefore, our goal was to provide a fast and environmentally friendly alternative to current methods to determine micropore volume, specific surface area and total pore volume, based on FTIR spectroscopy coupled with chemometric methods. Moreover, we have created classification models, which are capable of predicting the used feedstock materials from IR spectra. Our support vector machine–based classification model had the best accuracy values, above 0.86. Our classification and regression models have excellent performance and were properly validated, thus they are good alternatives for the robust and fast determination of the important qualitative and quantitative features of carbon samples.

Insights into the behavior and kinetics of purun tikus degradation during slow pyrolysis

Purun tikus (Elocharis dulcis), a type of wetland biomass feedstock, is a challenge to the swamp ecosystem as it contributes to pollution in the area. Hence, integrating the use of purun tikus as a source of bioenergy, particularly in the form of bio-oil, is of the highest priority. Nevertheless, there is a lack of research on the degradation rate of purun tikus conversion to bio-oil through pyrolysis. Thus, this study aims to evaluate the rate of destruction of purun tikus in the process of conversion into bio-oil via pyrolysis. In the experiment, a batch reaction vessel was used to carry out slow pyrolysis at temperatures ranging from 300 to 500 °C, and the reaction times ranged from 60 to 120 min. By assuming a first-order process and using the Arrhenius equation, it was possible to figure out the activation energy and the preexponential factort. To determine whether purun tikus destroyed during pyrolysis, an activation energy of 43.317 kJ mol-1 and a pre-exponential factor of 0.351 s-1 were identified.

Proportion of Nonindustrial Private Forest Lands That Potentially Can Be Leased to Bioenergy Enterprises to Grow Short Rotation Woody Crops

Abstract Determining how much nonindustrial private forest (NIPF) land could potentially be allocated to growing short rotation woody crops (SRWCs) is critical for estimating the future supply of woody biomass for biofuels and overall bioenergy production. This study estimated the proportion of the land NIPF landowners would be willing to allocate to SRWC cultivation. In view of the bounded nature of the dependent binary variable [0,1] and model performance, a fractional logit regression model was used to estimate model parameters. The estimated proportion of land allocated to SRWCs was positively influenced by the rental rate per acre, owning land for investment or fee-access hunting purposes, and the landowner’s age. In contrast, size of the ownership, owning land for the production of agricultural products, and residing on the land negatively influenced the proportion of land allocated to SRWCs. Lease contract duration, location of the largest tract owned, owning land for personal recreation or ecosystem services, and landowner familiarity with the concept of alternative fuels production did not influence the proportion of land allocated to SRWCs. These results will contribute to a better understanding of SRWC biomass supply from NIPF land and provide important benchmark information for conducting feasibility analyses of biofuel and biopower manufacturing in Mississippi and other states with abundant woody feedstocks. Study Implications: To achieve targeted levels of bioenergy production and carbon dioxide (CO2) emission reductions and diversify NIPF landowner income, participation of NIPF landowners in woody biomass feedstock production will be critical, because they own a majority of forestland in the region. Moreover, they have diverse reasons for owning land which has extensive implications not only in terms of incentive types or monetary compensation levels they might require for cultivating SRWCs but also policies related to the development of the bioenergy sector in Mississippi, the location of individual bioenergy processing facilities, and feedstock types that will be developed. Thus, forest managers and biomass procurement foresters might need to decide whether to focus their efforts on maximizing the land area allocated to growing SRWCs or considering a mix of SRWCs at lower lease rates per acre and material obtained from thinnings, which might be more amenable to landowners who value environmental amenities.

Multi-level framework for optimal operation of gasifier system utilising crop residues from small and medium-scale farms

Lack of techno-economic framework for optimal gasification and the identification of critical parameters for optimal operations is one of the major challenges restricting the gasification of crop residues. This study aims to develop an optimal techno-economic framework for the gasification of crop residues from clustered small/medium-scale farms. The developed model was applied to a case study in Adiembra, a farming community for a 10-kW gasifier engine system. Eight scenarios of individual feedstock and their blends were considered. The results revealed specific fuel consumption ranging from 1.79 – 3.53 kg/kWh. The economic analysis showed marginal profitability except for rice husk and straw which are not profitable. At the current grid electricity price, the minimum level of subsidies required to ensure the financial viability of the feedstocks is within the range of 30 – 70 % of the investment cost based on the various feedstock scenarios considered. The study revealed individual feedstocks with the best technical and economic prospects for optimal gasification to be cocoa pod husk, maize stalk and husk, maize cobs, rice straw and rice husk in the order of best to worst. The use of feedstock blends generally improved the overall syngas characteristics and financial viability. A total number of farms ranging between 107 – 532 are required to be clustered within a radius of 0.74 – 2.12 km with a cluster radius greater than 3.91 km not being financially viable. The fraction of each feedstock type in the blends were optimised with corresponding increase in syngas generation within the range of 9 – 35 % and decrease in the required number of farms within the range of 30 – 57 %. The outcome of the study demonstrates that sustainable gasification of crop residues for minigrid electricity generation requires co-gasification of various residue types, valorisation of by-products and increase in the current feed-in-tariff rate in Ghana.

Methane Production from a Rendering Waste Covered Anaerobic Digester: Greenhouse Gas Reduction and Energy Production

Livestock wastes can serve as the feedstock for biogas production (mainly methane) that could be used as an alternative energy source. The green energy derived from animal wastes is considered to be carbon neutral and offsetting the emissions generated from fossil fuels. In this study, an evaluation of methane production from anaerobic digesters utilizing different livestock residues (e.g., poultry rendering wastewater and dairy manure) was carried out. An anaerobic continuous flow system (15 million gallons, polyethylene-covered) subjected to natural conditions (i.e., high flow rate, seasonal temperatures, etc.) containing poultry rendering wastewater was set up to evaluate methane potential and energy production. A parallel pilot-scale plug-flow anaerobic digestion system (9 m3) was also set up to test different feedstocks and operating parameters. Biogas production was sampled and monitored by gas chromatography over several months of operation. The results showed that methane production increased as the temperature increased as well as depending on the type of feedstock utilized. The covered rendering wastewater lagoon achieved an upward of 80% (v/v) methane production. The rates of methane production were 0.0478 g per g of COD for the poultry rendering wastewater and 0.0141 g per g of COD for dairy manure as feedstock. Hence, a poultry processing plant with a rendering wastewater flow rate of about 4.5 million liters per day has the potential to capture about two million kilograms of methane for energy production per year from a waste retention pond, potentially reducing global warming potential by about 50,000 tons of CO2 equivalent annually.

Processes and Challenges for the Manufacturing of Lyocell Fibres with Alternative Agricultural Feedstocks

Lyocell man-made cellulosic fibres (L-MMCF) have been commercially available since the mid-1990’s, with the typical feedstock prepared from tree pulp or cotton linters. In recent years, there have been advancements in the utilisation of high alpha-cellulose agricultural biomass for L-MMCF feedstock. Industrial hemp stalks offer a unique opportunity for L-MMCF since hemp is considered an environmentally conscious crop that can also help to bridge the gap in worldwide cellulose shortages; additionally, industrial hemp stalks are high in alpha-cellulose, making this an ideal feedstock for L-MMCF manufacturing. This review paper outlines the lyocell process in detail, including processes for preparation of feedstocks, pulp processing, removal of contaminants and nonessential plant components, pulp dissolution, dope preparation, and fibre spinning. Opportunities and challenges associated with the utilisation of industrial hemp stalks as an alternative feedstock are addressed through all steps of the manufacturing process. Incorporating alternative feedstock opens new perspectives for manufacturing sustainable L-MMCF.

Characterization of spray dried cellulose nanofibrils produced by a disk refining process at different fineness levels

Three types of wood pulp feedstocks including bleached softwood kraft, unbleached softwood kraft and old corrugated containers were disk refined to produce cellulose nanofibrils at different fineness levels ranging from 50 to 100%, and the resulting aqueous suspensions of cellulose nanofibrils were spray dried. The spray drying experiments were carried out to examine different processing conditions for the different CNF feedstock types and fines level at various suspension concentrations to produce dry samples with free-flowing powder morphologies. The fineness levels and solids contents of CNF suspensions were set to 80% or more and 1.8% or less, respectively. If the solids content of the CNF solutions was high and the fibrillation level was low, plugging was experienced in the spray head because of the high viscosity of the suspensions, resulting in production of poor-quality powders. In terms of reduction in processing energy, even if the CNF suspension solids content was increased to 1.5 wt.%, the powder quality and the production yields were excellent. It was confirmed that high-quality powder under 20 µm were produced at a 90% fibrillation level of all CNF feedstocks. The resulting dry CNF powders were characterized to determine particle size distributions and morphological properties via a scanning electron microscope and a laser diffraction particle size analyzer. The particle sizes were smaller at higher fibrillation levels and lower solids content of the CNF suspensions. The CNF suspension derived from bleached kraft pulp, the average particle size decreased by 43% and 33% with the lowered solids contents from 1.8 to 1%, and the increased fineness levels from 80 to 100%, respectively.