Feedstock Characteristics Research Articles

Stone tools of the Neolithic settlement of Mergen 8

In this paper, stone tools of the Neolithic settlement of Mergen 8, located in the forest-steppe zone of Wes-tern Siberia in the Lower Ishim river basin, are analyzed. The mixed cultural layer of the settlement contained materials from two periods of its inhabitation, associated with the Boborykino Culture of the early Neolithic period and with the pottery ornamented with comb stamp of the late Neolithic period. The identification of the two chrono-logically different types of pottery raised the question of possibility of separating the stone implements. The aim of this work is to attempt differentiation from the mixed cultural layer of the groups of stone tools associated with a certain cultural and chronological section of the settlement. The peculiarity of the cultural layer of the Mergen 8 settle-ment was the presence of the dwelling 1 and some pits unimpaired by the upper horizons. In the methodological aspect of this work, stratigraphic and planigraphic analyzes with the aid of the feedstock characteristics of stone formed the basis, on which a relatively clean complex of quartz sandstone and flint was isolated, associated with the filling of the dwelling 1, in which pottery of the Boborykino Culture was found. The differentiation of the stone tools from the mixed layer was based upon the raw material that was found in the bottom part of the dwelling’s ditch, undisturbed by other layers. The complex of the stone tools made of jasper quartzite and schist, established during the field fixation, is associated with the comb-type pottery. Thus, in the course of our study, out of 417 finds of the stone tools 276 (66 % of the entire complex) were assigned to the Boborykino complex, 50 (12 %) to the comb complex, and 91 finds (22 %) were not possible to attribute to any type of pottery. Bearing in mind that separation by feedstock has a cer-tain degree of conventionality, it should be noted that the stone taken from the undisturbed near-bottom part of the Boborykino dwelling 1 reflects the most plausible nature of the stone industry of this period of inhabitation. In addi-tion, in our opinion, attempts to link stone implements and their features with a certain type of pottery facilitate the formation of a clear concept of the development of the stone industry in the region in the Neolithic.

Physics-informed machine learning methods for biomass gasification modeling by considering monotonic relationships

Machine learning methods have recently shown a broad application prospect in biomass gasification modeling. However, a significant drawback of the machine learning approaches is their poor physical interpretability when relying on limited experimental data. In the present work, a physics-informed neural network method (PINN) is developed to predict biomass gasification products (N2, H2, CO, CO2, and CH4). PINN simultaneously considers regression, structure, and physical monotonicity constraints in the loss function, providing physically feasible predictions. Specifically, the PINN models have outperformed prediction capability (average test R2 0.91–0.97) compared to five other machine learning methods through 50 times random sample classifications. Furthermore, it is demonstrated that the developed models can maintain correct monotonicity even if the feedstock characteristics or gasification conditions are outside the training data. By using a reliable physical mechanism to guide machine learning, the model can ensure better generalizability and scientific interpretability.

Subcritical Water Hydrolysis of Fresh and Waste Cooking Oils to Fatty Acids Followed by Esterification to Fatty Acid Methyl Esters: Detailed Characterization of Feedstocks and Products.

In this present work, the hydrolysis of a sample of rapeseed oil (RSO) and two waste cooking oil (WCO) samples in subcritical water has been carried out in a stirred batch stainless-steel reactor to produce fatty acids. Using RSO as a model triglyceride, the effects of reaction parameters on the yields of fatty acids were investigated to determine the optimum set of hydrolysis conditions to be a temperature of 300 °C, a reaction time of 60 min, and a vegetable oil-water mass ratio of 1:2. The set of optimum conditions was applied to the hydrolysis of the WCOs. Oleic acid was the dominant fatty acid with yields of 74.4 wt % from RSO and 57.5 and 72.4 wt % from the two WCOs, respectively, while palmitic acid was the second most abundant fatty acid with yields of up to 31 wt %. The feedstocks and fatty acid products were characterized by acid-base titration and thermogravimetric analysis (TGA). Thereafter, the hydrolysis products from the optimum conditions were esterified to their fatty acid methyl esters (FAMEs), which were further characterized by gas chromatography-mass spectrometry (GC/MS) and TGA. With RSO at the optimum hydrolysis conditions, acid-base titration gave a fatty acid yield of 97.2 wt %, while TGA gave 86 wt %. Under the same conditions, the yield of FAMEs from GC/MS analysis was 88.6 wt %, while TGA gave a FAMEs' yield of 91 wt %. This study showed that the simple TGA method provided detailed and complete characterization of lipid feedstocks and their conversion products. In addition, subcritical water hydrolysis can be used to valorize WCOs to fatty acids, with little or no extensive feedstock purification, for various applications including biodiesel production.

Exposing and understanding synergistic effects in co-pyrolysis of biomass and plastic waste via machine learning

During co-pyrolysis of biomass with plastic waste, bio-oil yields (BOY) could be either induced or reduced significantly via synergistic effects (SE). However, investigating/ interpreting the SE and BOY in multidimensional domains is complicated and limited. This work applied XGBoost machine-learning and Shapley additive explanation (SHAP) to develop interpretable/ explainable models for predicting BOY and SE from co-pyrolysis of biomass and plastic waste using 26 input features. Imbalanced training datasets were improved by synthetic minority over-sampling technique. The prediction accuracy of XGBoost models was nearly 0.90 R2 for BOY while greater than 0.85 R2 for SE. By SHAP, individual impact and interaction of input features on the XGBoost models can be achieved. Although reaction temperature and biomass-to-plastic ratio were the top two important features, overall contributions of feedstock characteristics were more than 60 % in the system of co-pyrolysis. The finding provides a better understanding of co-pyrolysis and a way of further improvements.

Catalytical thermal conversion of waste fishing nets for a higher added value energy products generation and caprolactam recovery

The ongoing eutrophication processes and water pollution caused by marine plastic waste are relevant ecological problem. Collected wastes are possible alternative feedstock for additional higher added value energy product generation. Moreover, caprolactamis the main compound of nylon-6 waste fishing nets and its recovery conserves natural resources, maximizes waste economic performance, and closes the circular economy loop of the fishing net industry. In order to contribute to the creation of circular economy, investigation of pyrolysis process and the effect of catalyst synergy with different temperatures on the formulated products has been performed. This work aims to analyse the used fishing nets (FN), using TGA-DTG-FTIR systems and mini pyrolysis plant. Experiments were conducted with Y-type zeolite and ZSM-5 as catalysts with a ratio of 1 by 3 and 1 by 8, respectively. Micro-thermal analysis using the TGA-DTG-FTIR system was processed for feedstock characterization purposes, which showed that the fishing gear has one minor decomposition peak around 200 °C, and the major one around 450 °C, with a total weight loss of 88 wt%. Pyro-oils analysis showed that the main fractions could be assigned to aromatic and aliphatic hydrocarbons, such as naphthalene, styrene, and toluene. Moreover, the recovery of caprolactam shows a possibility to obtain not only energy products, but also higher added value chemical derivatives. Temperature and catalyst synergetic approach influence for the recovered products investigation showed the optimum conditions as 700 °C for the highest purity and quality products generation. Based on the results, catalytic thermal treatment at 700 °C with Y-Type could be adapted as a promising technique for extracting of caprolactam with a high yield (96 %).

An inclusive numerical framework to assess the role of feedstock features on the quality of cold spray deposits

Cold spray technology provides unique capabilities for coating, repair, and additive manufacturing. However experimental trial and error to optimize deposit quality indexes, that rely on powder characteristics, can be costly and tedious. In this research, multiple finite element modelling approaches were compared regarding their capability and shortcomings to analyze the role of major powder features on deposit properties. Lagrangian and CEL methods were selected as the most robust approaches for analyzing the single/multi-particle impact condition, respectively. An intricate algorithm was introduced to accurately evaluate the effect of parameters including particle size, shape, oxidation extent, and impact angle on the deposition indicators such as critical velocity, particle flattening, and deposit porosity. The results exhibited a good agreement with the reported experimental data, confirming the capacity of the proposed numerical framework to tune the deposit properties as a function of a wide range of feedstock characteristics. It was concluded that for successful deposition, the effect of various powder properties and their respective effect and contribution towards plastic deformation should be taken into account. The results indicated that for a given particle velocity, smaller particle, more irregular morphology, thicker oxide layer, and smaller impact angle will result in limited particle deformation and a lower possibility of successful adhesion.

Solvent extraction and characterization of Brassica carinata oils as promising alternative feedstock for bio-jet fuel production.

As a fossil fuel substitute, bio-jet fuel derived from inedible oilseed crops has the potential to improve energy security, decrease carbon footprint, and promote agricultural economy and social development. The efficient production of bio-jet fuels depends on the identification and characterization of eco-friendly and sustainable feedstocks. Brassica carinata (Arun Braun) cultivars are among the most significant industrial oilseeds that can be utilized as alternative feedstocks in the aviation industry. The study thoroughly evaluated four non-food Brassica carinata cultivars that are indigenous to Ethiopia to determine their suitability as substitute feedstocks for the production of bio-jet fuel. The effects of solvent extraction parameters were studied using response surface methodology with Box-Behnken design in an isothermal batch reactor. Physicochemical characterization, fatty acids profiling, ultimate analysis, analysis of metals and phosphorus concentration, Fourier-transform infrared spectroscopy characterization, and calorific value analyses were performed to characterize the properties of oils. Accordingly, oil yields ranged from 35.93 to 45.25%. Erucic acid (EA) was the most predominant fatty acid in all oils, accounting for 42-50%, of Derash and Yellow Dodolla oils, respectively, making Yellow Dodolla oil a super-high erucic acid oil. In comparison to the other oils, Yellow Dodolla was observed to be the least oxygenated oil, with a 7.80% oxygen content and oxygen to carbon ratio of 0.07, which may enable it to consume a very limited amount of hydrogen gas during hydrodeoxygenation in bio-jet fuel production. It was determined that, except for calcium and phosphorous levels in Tesfa, the concentrations of the metals and phosphorous were very small. Alkanes, alkenes, carboxylic acids, esters, alcohols, aromatics, and olefins were among the most significant and main functional groups identified. Our extraction and characterization results revealed that the Brassica carinata cultivars have very high oil contents, better physicochemical properties, excellent fatty acid profiles, and very low concentrations of heteroatoms (nitrogen, sulfur), metals and phosphorous concentrations, and very low level of oxygen to carbon ratios, making the oils, notably Yellow Dodolla oil, very high quality and promising alternative feedstocks for upgrading of the oils into bio-jet fuels through hydroprocessing pathway.

Reviewing the effect of pyrolysis temperature on the fourier-transform infrared spectra of biochars

Abstract Pyrolysis of feedstocks to produce biochar for soil remediation employed to be a convenient method regarding improvement of soil fertility, increasing carbon stability and decreasing greenhouse gas emissions. Biochar properties and its effect after incorporation into the soils vary depending on the characteristics of feedstocks and pyrolysis process. This paper aims to compare the effect of pyrolysis temperature on the frequency of functional groups in different biochars made from plant feedstocks over the temperature range from 300 °C to 700 °C. An increase in pyrolysis temperature positively affects biochar surface properties until the deformation step in C = O, –COOH, and OH groups and as a result, the surface area of biochar decreases at high temperature (more than 600 °C). The breakdown of hemicellulose, cellulose, and lignin also occurs at temperatures more than 600 °C. Consequently, the biochar quality is reduced with increasing pyrolysis temperature although such biochar may be suitable for rising the content of stable carbon in the soils. Over the long-term, the stability of biochar can contribute to carbon sequestration, retention of water and ions in the soil.

Microbial life strategy with high rRNA operon copy number facilitates the energy and nutrient flux in anaerobic digestion

Microbial life strategy, reflected by rRNA operon (rrn) copy number, determines microbial ecological roles. However, the relationship between microbial life strategy and the energy and nutrient flux in anaerobic digestion (AD) remains elusive. This study investigated microbial rrn copy number and expression ratio using amplicon sequencing of 16S rRNA gene and 16S rRNA, and monitored CH4 daily production to approximate the status of energy and nutrient flux in semi-continuous AD. A significantly positive correlation between the mean rrn copy number of microbial communities in digestate and CH4 daily production was detected in the control treatment fed swine manure. The reduced feedstock complexity, by replacing parts of swine manure with fructose or apple waste, weakened the correlation. When feedstock complexity was increased again, the correlation was strengthened again. Similar results were detected in mean rrn expression ratio of microbial communities. The responses of mean rrn copy number and expression ratio of communities to feedstock addition differed between the reduced feedstock complexity and the control treatment, as well as between in digestate and in straw. Our findings reveal a novel relationship between microbial community life strategy and the energy and nutrient flux, and the roles of feedstock characteristics therein in AD.

Recycling of post-consumption food waste through pyrolysis: Feedstock characteristics, products analysis, reactor performance, and assessment of worldwide implementation potentials

Food waste produced in households, public restaurants, and hospitality sectors is causing serious concerns due to its negative environmental impact and the associated cost of disposal in landfills. This paper presents a comprehensive experimental assessment of post-consumption food waste characteristics, its conversion to added-value products through pyrolysis, and its potentials for worldwide large-scale processing. Analysis of the food waste samples revealed highly desirable features (e.g., volatile = 75.2%, lipid = 15.4%, and HHV = 20.1 MJ kg−1). The overall pyrolysis yield was 37.2% bio-oil, 14.2% aqueous phase, 27.6% biochar, and 21.0% non-condensable gas. The bio-oil showed attractive fuel characteristics (HHV = 28.2 MJ kg−1, water content = 4.6%, and pH = 6), however, the viscosity was high (136 cSt). The most abundant compounds in the bio-oil were major fatty acids commonly found in dairy fats, meat, and hydrogenated vegetable oils. The biochar has an improved characteristic (HHV = 26.3 MJ kg−1 and O/C = 0.065), which makes it potentially useful for energy applications as well as for long-term carbon sequestration if used in soil amendment. The non-condensable gas has an energy content of 15.8 MJ kg−1, nearly 30% that of natural gas. In assessing the worldwide potential implementation of food waste pyrolysis, the calculations indicate that Eastern and Southern Asia, followed by sub-Saharan Africa, respectively, are of the highest potential for large-scale processing. The estimated world’s energy output is 1376.2 GW and this is predicted to contribute to around 30% to the world’s demand of renewable energies by 2026, if this feedstock is fully utilized. Most importantly, the outcome of this study is highly encouraging for the development of bioenergy technology in regions where conventional biomass resources are limited, such as arid and semi-arid regions.

Lignocellulose degradation by Penicillium janthinellum enzymes is influenced by its variable secretome and a unique set of feedstock characteristics

Substrate characteristics and proteins that affect lignocellulose-hydrolysis by the hypercellulolytic fungus Penicillium janthinellum NCIM 1366 (PJ-1366) were investigated. The hydrolysis rate of PJ-1366 enzymes was very high, with upto 75 % of the reaction being completed in initial 4 h. Comparison of the hydrolytic efficiencies on differently pretreated biomass indicated that the greatest (negative) effect was imparted by lignin, suggesting that improving ligninase activity of the PJ-1366 enzymes may help to improve hydrolysis. Larger pore sizes and higher crystallinity of substrates, which favor enzyme penetration and processive hydrolysis, positively influenced hydrolysis efficiency. For alkali-pretreated substrates, 16 FPU/g of PJ-1366 cellulases released the sugar-equivalent of using 10 FPU/g of a commercial biomass hydrolyzing enzyme. By correlation analysis, 41 proteins, including 20 CAZymes were identified, whose abundance in the secretome positively correlated with the cellulase activities of the culture filtrate. These proteins may be considered as the primary drivers of FPase/CMCase/pNPGase/xylanase activity in PJ-1366.

Phosphorus retention and agronomic efficiency of refined manure-based digestate—A review

Digestate, a by-product from anaerobic digestion of organic materials such as animal manure, is considered a suitable plant fertilizer. However, due to its bulkiness and low economic value, it is costly to transport over long distances and store for long periods. Refinement processes to valorize digestate and facilitate its handling as a fertilizer include precipitation of phosphorus-rich mineral compounds, such as struvite and calcium phosphates, membrane filtration methods that concentrate plant nutrients in organic products, and carbonization processes. However, phosphorus retention efficiency in output products from these processes can vary considerably depending on technological settings and characteristics of the digestate feedstock. The effects of phosphorus in plant fertilizers (including those analogous or comparable to refined digestate products) on agronomic productivity have been evaluated in multiple experiments. In this review, we synthesized knowledge about different refinement methods for manure-based digestate as a means to produce phosphorus fertilizers, thereby providing the potential to increase phosphorus retention in the food production chain, by combining information about phosphorus flows in digestate refinement studies and agronomic fertilizer studies. It was also sought to identify the range, uncertainty, and potential retention efficiency by agricultural crops of the original phosphorus amount in manure-based digestate. Refinement chains with solid/wet phase separation followed by struvite or calcium phosphate precipitation or membrane filtration of the wet phase and carbonization treatments of the solid phase were included. Several methods with high potential to extract phosphorus from manure-based wet phase digestate in such a way that it could be used as an efficient plant fertilizer were identified, with struvite precipitation being the most promising method. Synthesis of results from digestate refinement studies and agronomic fertilizer experiments did not support the hypothesis that solid/wet separation followed by struvite precipitation, or any other refinement combination, results in higher phosphorus retention than found for unrefined digestate. Further studies are needed on the use of the phosphorus in the solid phase digestate, primarily on phosphorus-rich soils representative of animal-dense regions, to increase understanding of the role of digestate refinement (particularly struvite precipitation) in phosphorus recycling in agricultural systems.

Injection Molding and Sintering of ZrO2 Ceramic Powder Modified by a Zirconate Coupling Agent.

Ceramic injection molding is a near-net shape-processing technique, producing ceramic components with low tooling costs and complex shapes. In this paper, ZrO2 ceramics with high loading content in the green part were prepared by powder modification using zirconate coupling agent, injection molding and sintering, which benefited decreasing the usage of binders and deformation of ceramics. The rheological characteristics of feedstocks, densities, microstructures and mechanical properties of green and sintered parts with the different coupling media and sintering temperatures were studied. The results showed that the addition of a zirconate coupling agent with ethanol medium obviously increased the flowability of feedstocks and benefited achieving the green parts with high powder loading (86.5 wt.%) and bending strength (12.9 MPa) and the final unbroken ceramics. In addition, the sintering temperatures from 1500–1575 °C had no significant effects on the density, hardness, and surface morphology of the ceramic samples. However, the bending strength increased and some large grains with transgranular fracture occurred on the fractural surface at the sintering temperature of 1575 °C.

Investigation of the potential of greenhouse post-harvest wastes for bioenergy production and utilization for heating and carbon dioxide application

In this study, raw biomass feedstock characterization of greenhouse post-harvest residues of tomato, pepper, and eggplant has been investigated using the wastes of stem and leaves as a source of energy gained from palletization. The characterization was compared to both sawdust and the relevant ISO and EU pellet standards. The proximate and ultimate analyses results of all the tested feedstock materials have proven to be successful candidates for pelletizing and combustion process. The bulk density of tomato, pepper, and eggplant pellets were found to be 568 kg/m3, 575 kg/m3, 589 kg/m3, respectively, and the higher heating values of these produces were found to be 17.25 MJ/kg, 17.45 MJ/kg, and 17.80 MJ/kg, respectively. Based on the results, it is possible to generate 10 tons of waste per hectare capable of producing almost 50 MWh of heating energy. Furthermore, this waste could generate more than 6.5 tons of CO2 per hectare. The study results suggest that the heating energy potential and the amount of CO2 emitted could be used in greenhouses to support photosynthesis during low temperature and low solar radiation periods.

Elucidating the microbiome of the sustainable peat replacers composts and nature management residues.

Sustainable peat alternatives, such as composts and management residues, are considered to have beneficial microbiological characteristics compared to peat-based substrates. Studies comparing microbiological characteristics of these three types of biomass are, however, lacking. This study examined if and how microbiological characteristics of subtypes of composts and management residues differ from peat-based substrates, and how feedstock and (bio)chemical characteristics drive these characteristics. In addition, microbiome characteristics were evaluated that may contribute to plant growth and health. These characteristics include: genera associated with known beneficial or harmful microorganisms, microbial diversity, functional diversity/activity, microbial biomass, fungal to bacterial ratio and inoculation efficiency with the biocontrol fungus Trichoderma harzianum. Bacterial and fungal communities were studied using 16S rRNA and ITS2 gene metabarcoding, community-level physiological profiling (Biolog EcoPlates) and PLFA analysis. Inoculation with T. harzianum was assessed using qPCR. Samples of feedstock-based subtypes of composts and peat-based substrates showed similar microbial community compositions, while subtypes based on management residues were more variable in their microbial community composition. For management residues, a classification based on pH and hemicellulose content may be relevant for bacterial and fungal communities, respectively. Green composts, vegetable, fruit and garden composts and woody composts show the most potential to enhance plant growth or to suppress pathogens for non-acidophilic plants, while grass clippings, chopped heath and woody fractions of compost show the most potential for blends for calcifuge plants. Fungal biomass was a suitable predictor for inoculation efficiency of composts and management residues.

Condition Monitoring of a Three-Cathode Cascaded Plasma Spray Torch Regarding Process Reliability.

The TriplexPro™-210 plasma spray torch (Oerlikon Metco) is a three-cathode plasma generator. It became a kind of workhorse for the wide range of tasks handled at the Jülich Thermal Spray Center (JTSC). Compared to conventional single-cathode torches, the cascaded design of the nozzle suggests low fluctuations of the arc and thus high stability. However, after a certain time, degradation sets in even with such a torch, impairing the reliability of the process. It is therefore important to detect indications of performance loss in time and not only during the inspection of the deposited layer. In this study, standard samples of YSZ thermal barrier coatings were sprayed regularly over a period of two years. Operational data and feedstock characteristics were collected and correlated with the area-specific mass deposition. It turned out that the measured substrate surface temperature showed a distinct correlation. Searching for the reasons for the temperature variations, several process parameters could be ruled out as they are monitored by calibrated sensors, controlled, and their time course is recorded by the control unit. Moreover, there are other parameters, which can have a considerable impact such as the robot alignment or the substrate cooling conditions. However, the purposeful experimental variation of such variables resulted in a variability of the mass deposition being considerably smaller than observed over the two years. Thus, it can be concluded that torch degradation had a pronounced effect, too. The substrate surface temperature can be used as indicator for the torch status and the reliability of the spray process.

A Short Review on Feedstock Characteristics in Methane Production from Municipal Solid Waste

Abstract The increase in population and industrialization leads to an increase in the solid waste year by year. The limited availability, increasing cost and adverse effect of climate change on fossil fuel leads to encouraging the research in the field of finding alternatives for energy sources. The organic fraction of municipal solid waste (OFMSW) can be utilized as a bio-energy source, which reduces the environmental impact and the requirement of landfill areas to dispose of municipal solid waste. Anaerobic digestion is the widely used sustainable approach to treat OFMSW. In recent years, the generation of methane from municipal solid waste has received increasing attention in research. This paper reviews literature published in recent years considering various characteristics of input feedstock parameters like pH, total solids, volatile solids, and water content which affect the digestion quality of the OFMSW and increase the production of methane. A regression model is developed to identify the relationship between methane production and various feedstock parameters. When the chemical compositions of feedstock were used as independent variables, the percentage variation accounted for by the model is low (r2 = 0.63) and also the important observation from the analysis is that the pH of the feedstock influences majorly methane production.

Microwave-assisted pyrolysis spent bleaching clay for aromatic bio-oil production: Exploration of heating pathway based on microwave response characteristics of feedstock

Spent bleaching clay (SBC) is a waste generated from the refining process of edible oils. SBC contains some residual oils, with excellent potential to produce aromatic bio-oil. For the first time, microwave-assisted pyrolysis was used to treat SBC, which has unique microwave response characteristics. The products of microwave heating and electric heating were investigated, under three conditions: no catalyst, in-situ catalysis, and ex-situ catalysis. Microwave heating saved 50% of the reaction time and up to 53% of the energy consumption, compared to electric heating. Microwave heating facilitated the formation of aromatic hydrocarbons by promoting hydrogen transfer and cyclization reactions. In comparison with electric heating, the aromatic hydrocarbons relative content was increased by 15.46% under no catalyst. In addition, the optimal pyrolysis temperature, catalytic temperature, feedstock to catalyst mass ratio (F/C) and nitrogen flow rate based on microwave heating pathway were 500 °C, 500 °C, 10/1, and 50 mL/min, respectively. Under these conditions, the relative content of aromatic hydrocarbons was 87.89%. Microwave-assisted catalytic pyrolysis is a fast and energy efficient pathway to produce aromatic bio-oil from SBC, which can provide a theoretical basis for resource utilization of SBC.

Optimization of substrate mixing ratios for wet anaerobic digestion of selected organic waste streams for productive biogas systems

In order to realize the objective of productive biogas systems, which is to provide waste management and modern renewable energy services, sustainable biogas production is paramount. While there are several factors that affect sustainability, quality of substrate for biogas production is one key anaerobic digestion (AD) parameter that should be optimized for improved and sustainable biogas yield. Since heterogeneity is an inherent characteristic of biomass, it is important that before application of any given biomass material for AD, its key characteristics are first examined to guide further processing to meet standards for optimal biogas recovery. In this study, physical and chemical characteristics of selected feedstocks were examined with intent to develop optimal substrate mixing ratios to improve quality of substrate for optimal biogas yield. Mathematical modeling of the required substrate moisture concentration was done, which gave way to the determination of optimal substrate mixing ratios. Results indicate that characteristics of feedstock vary widely according to source and type, as well as their substrate mixing ratios. However, for chicken litter with rice hull, the substrate mixing ratio was statistically not different from that of chicken litter with coffee husks and wood shavings, and therefore can be used on all the three feedstocks without significant effects on biogas yield.

The conversion of biomass to fuels via cutting-edge technologies: Explorations from natural utilization systems

Biomass can be used to manufacture both hydrocarbon fuels and chemical compounds such as rubber, alcohols, lipid-based products, sugars, etc. Due to their abundant supply and lower greenhouse gas emissions, fuels derived from biomass have received much attention in recent years. Biofuels can be made from grasses, agricultural waste, animal waste and trash, old oils, and other organic things. The characteristics of various feedstocks and fuels, as well as the techniques for converting biomass to biofuels, physical and chemical parameters, and limitations that affect biomass to fuel conversion, are all discussed. pH, temperature, and residence time are all process parameters. Other chemical factors include the availability of carbon, nutrients, acid and alkaline hydrolysis agents, phenolic inhibitors, and sugars produced throughout the process. The list of obstacles to biomass bioconversion includes reduced particle size, crystallinity, fermentation inhibitory byproducts, cellulase deactivation, yeast ethanol tolerance, and sugar co-fermentation. The research and development of biomass-to-energy conversion technology have been accelerating significantly, according to this review. The choice of the conversion method depends on the type and quality of the biomass, the final energy form, environmental requirements, economic conditions, and project-specific considerations. Biowaste is initially improved (depending on the conditions). This process includes size reduction, densification, drying, and torrefaction. The two most popular conversion methods for biomass to energy are thermochemical and biochemical. Utilizing the power of microorganisms, biochemical conversion transforms biomass into liquid or gaseous fuels. The processes of anaerobic digestion, fermentation, and photobiological hydrogen generation are currently the most widely used biochemical technologies. Recent advancements in recombinant DNA technology and protein engineering, as well as future technology like extraction, and application towards green, are targeted at addressing bioconversion restrictions.