Production of Electricity and Heat from Biomass Wastes Using a Converted Aircraft Turbine AI-20

Unlocking the potential: Evolving role of technical lignin in diverse applications and overcoming challenges

Recent advancements have transformed lignin from a byproduct into a valuable raw material for polymers, dyes, adhesives, and fertilizers. However, its structural heterogeneity, variable reactive group content, impurities, and high extraction costs pose challenges to industrial-scale adoption. Efficient separation technologies and selective bond cleavage are crucial. Advanced pretreatment methods have enhanced lignin purity and reduced contamination, while novel catalytic techniques have improved depolymerization efficiency and selectivity. This review compares catalytic depolymerization methodologies, highlighting their advantages and disadvantages, and noting challenges in comparing yield values due to variations in isolation methods and lignin sources. Recognizing "technical lignin" from pulping processes, the review emphasizes its diverse applications and the necessity of understanding its structural characteristics. Emerging trends focus on bio-based functional additives and nanostructured lignin materials, promising enhanced properties and functionalities. Innovations open possibilities in sustainable agriculture, high-performance foams and composites, and advanced medical applications like drug delivery and wound healing. Leveraging lignin's biocompatibility, abundance, and potential for high-value applications, it can significantly contribute to sustainable material development across various industries. Continuous research in bio-based additives and nanostructured materials underscores lignin's potential to revolutionize material science and promote environmentally friendly industrial applications.

Exploration of the Interrelationship within Biomass Pyrolysis Liquid Composition Based on Multivariate Analysis

The diverse utilization of pyrolysis liquid is closely related to its chemical compositions. Several factors affect PA compositions during the preparation. In this study, multivariate statistical analysis was conducted to assess PA compositions data obtained from published paper and experimental data. Results showed the chemical constituents were not significantly different in different feedstock materials. Acids and phenolics contents were 31.96% (CI: 25.30−38.62) and 26.50% (CI: 21.43−31.57), respectively, accounting for 58.46% (CI: 46.72−70.19) of the total relative contents. When pyrolysis temperatures range increased to above 350 °C, acids and ketones contents decreased by more than 5.2-fold and 1.53-fold, respectively, whereas phenolics content increased by more than 2.1-fold, and acetic acid content was the highest, reaching 34.16% (CI: 25.55−42.78). Correlation analysis demonstrated a significantly negative correlation between acids and phenolics (r2 = −0.43, p < 0.001) and significantly positive correlation between ketones and alcohols (r2 = 0.26, p < 0.05). The pyrolysis temperatures had a negative linear relationship with acids (slope = −0.07, r2 = 0.16, p < 0.001) and aldehydes (slope = −0.02, r2 = 0.09, p < 0.05) and positive linear relationship with phenolics (slope = 0.04, r2 = 0.07, p < 0.05). This study provides a theoretical reference of PA application.

Dispersed Power Production in Terms of the Potential of Briquettes Made from Straw and Willow as Renewable Sources of Energy

The rapid development of agricultural technologies has triggered new possibilities of using plant waste as fuel. Briquetting plant material is one of the methods of using crop residue as permanent energy carriers. Nevertheless, to maintain the normalised properties of briquettes, their small-scale production should follow an established and well-considered deliberate technological process limiting production costs. The material to be used for energy production should, in particular, be pre-prepared in terms of crushing and moisture content to ensure the right product parameters. The article aims to provide an analysis of briquettes with varied physicochemical parameters to determine and order homogenous groups for selected parameters characteristic for briquettes made from various bioenergy materials. The specific aim of the article required a statistical analysis as a tool for separating the selected factors. An analysis of variance (ANOVA) was involved, together with a post-hoc Duncan test. The analyses demonstrated that the briquette composition, such as bulk value, moisture, and ash content can enhance the briquette quality. In discussion, the straw used was compared with other kinds of agricultural biomass samples and considerable differences were identified. The chemical analysis showed a high content of carbon (from 42.64 to 45.66%) and oxygen (from 47.60 to 49.68%). The percentage share of hydrogen in the chemical structure of the materials accounted for approximately 6%. The ash content found while investigating various straw types ranged from 3.67 to 4.26%, making it lower than reported in the literature. The study also looked at the energetic potential of straw and wood biomass. It was noticed that bioenergetic sources are much potentially higher than the materials used in the traditional power sector. Especially where it concerns an unlimited source that can be provided to the bio-energetic sector. The study is intended to focus the future energy sector on the use of bioenergy in terms of applying straw to energy production purposes.

Gasification of Biomass: The Very Sensitive Monitoring of Tar in Syngas by the Determination of the Oxygen Demand—A Proof of Concept

A novel method for quasi-continuous tar monitoring in hot syngas from biomass gasification is reported. A very small syngas stream is extracted from the gasifier output, and the oxygen demand for tar combustion is determined by a well-defined dosage of synthetic air. Assuming the total oxidation of all of the combustible components at the Pt-electrode of a lambda-probe, the difference of the residual oxygen concentrations from successive operations with and without tar condensation represents the oxygen demand. From experiments in the laboratory with H2/N2/naphthalene model syngas, the linear sensitivity and a lower detection limit of about 70 ± 5 mg/m3 was estimated, and a very good long-term stability can be expected. This extremely sensitive and robust monitoring concept was evaluated further by the extraction of a small, constant flow of hot syngas as a sample (9 L/h) using a Laval nozzle combined with a metallic filter (a sintered metal plate (pore diameter 10 µm)) and a gas pump (in the cold zone). The first tests in the laboratory of this setup—which is appropriate for field applications—confirmed the excellent analysis results. However, the field tests concerning the monitoring of the tar in syngas from a woodchip-fueled gasifier demonstrated that the determination of the oxygen demand by the successive estimation of the oxygen concentration with/without tar trapping is not possible with enough accuracy due to continuous variation of the syngas composition. A method is proposed for how this constraint can be overcome.

Biochar Synthesis from Mineral- and Ash-Rich Waste Biomass, Part 1: Investigation of Thermal Decomposition Mechanism during Slow Pyrolysis

Synthesizing biochar from mineral- and ash-rich waste biomass (MWB), a by-product of human activities in urban areas, can result in renewable and versatile multi-functional materials, which can also cater to the need of solid waste management. Hybridizing biochar with minerals, silicates, and metals is widely investigated to improve parent functionalities. MWB intrinsically possesses such foreign materials. The pyrolysis of such MWB is kinetically complex and requires detailed investigation. Using TGA-FTIR, this study investigates and compares the kinetics and decomposition mechanism during pyrolysis of three types of MWB: (i) mineral-rich banana peduncle (BP), (ii) ash-rich sewage sludge (SS), and (iii) mineral and ash-rich anaerobic digestate (AD). The results show that the pyrolysis of BP, SS, and AD is exothermic, catalyzed by its mineral content, with heat of pyrolysis 5480, 4066, and 1286 kJ/kg, respectively. The pyrolysis favors char formation kinetics mainly releasing CO₂ and H₂O. The secondary tar reactions initiate from ≈318 °C (BP), 481 °C (SS), and 376 °C (AD). Moreover, negative apparent activation energies are intrinsic to their kinetics after 313 °C (BP), 448 °C (SS), and 339 °C (AD). The results can support in tailoring and controlling sustainable biochar synthesis from slow pyrolysis of MWB.

Hydrothermal Conversion of Waste Biomass from Greenhouses into Hydrochar for Energy, Soil Amendment, and Wastewater Treatment Applications

Solid hydrochar (HC) produced by hydrothermal carbonization (HTC) of tomato plant biomass from a greenhouse (GH) was assessed for different inhouse applications, including fuel, seed germination, and leached GH nutrient feed (GNF) wastewater treatment. Completed experiments showed encouraging results. HC was revealed to be an efficient renewable fuel, having peat-like characteristics with high heating value of about 26.0 MJ/kg and very low clinker forming potential. This would allow the use of HC as fuel for GH heating as a substitute to costly natural gas, or it could be commercialized after pelletizing. Experiments with soil application showed substantial potential for the produced HC in better seed germination of tomato plants. Another benefit from use of the produced HC is as a soil additive, which would also contribute to environmental emission reduction. Results suggest that the generated HC can remove about 6–30% of nutrients from leached-GNF wastewater. This would be an essential treatment in the reduction of nutrients from leached water from GH operations, and thus could prevent/reduce eutrophication. The exhausted HC after treatment application could then be reused for soil remediation. Overall, the paper highlights the potential applications of hydrothermal treatment in valorization of low-valued GH TPB waste, resulting in a circular economy.

Pyrolysis of Biomass Wastes into Carbon Materials

This study presents the results of the biomass pyrolysis process focusing on biochar production and its potential energetic (as solid fuel) and material (as adsorbent) applications. Three kinds of biomass waste were investigated: wheat straw, spent coffee grounds, and brewery grains. The pyrolysis process was carried out under nitrogen atmosphere at 400 and 500 °C (residence time of 20 min). A significant increase in the carbon content was observed in the biochars, e.g., from 45% to 73% (at 400 °C) and 77% (at 500 °C) for spent coffee grounds. In addition, the structure and morphology were investigated using scanning electron microscopy. Thermal properties were studied using a simultaneous thermal analysis under an oxidising atmosphere. The chemical activation was completed using KOH. The sorption properties of the obtained biochars were tested using chromium ion (Cr3+) adsorption from liquid solution. The specific surface area and average pore diameter of each sample were determined using the BET method. Finally, it was found that selected biochars can be applied as adsorbent or a fuel. In detail, brewery grains-activated carbon had the highest surface area, wheat straw-activated carbon adsorbed the highest amount of Cr3+, and wheat straw chars presented the best combustion properties.

Production Processes Related to Conventional and Renewable Energy in Enterprises and in the Circular Economy

In modern enterprises, all processes that are understood as structured activities intended for production, i [...]

Tribological Behavior of Biomass Fast Pyrolysis Fuel and Diesel Blends

The original biomass fast pyrolysis fuel was modified by an emulsification method to obtain emulsified biomass fast pyrolysis fuel with different proportions (the content of biomass fast pyrolysis fuel in the emulsified biomass fuel was 5 wt.%, 10 wt.%, and 20 wt.%, respectively). Taking commercial 0# diesel as the blank fuel, the friction and wear characteristics of tribo-pair material from an actual piston ring–cylinder liner lubricated by the varied fuels were investigated on a reciprocating friction and wear tester, respectively. The results showed that the friction coefficient and wear of tribo-pair material lubricated with emulsified biomass fuel increased with the biomass fuel content. In the case of 5 wt.% emulsified biomass fuel, the friction coefficient was smaller than 0# diesel, and the wear was not different from 0# diesel. At the same time, the friction coefficient and wear of 5 wt.% emulsified biomass fuel increased with the reciprocating frequency when the load was constant, while they increased with the load when the reciprocating frequency was constant.

Effects of Biomass Fast Pyrolysis Fuel on the Tribological Behaviour of Heavy-Duty Diesel Engine Lubricating Oil

The fuel type not only influences the engine power and exhaust emissions, but dilutes the lubricating oil. We studied the effects of biomass fast pyrolysis fuel, or biofuel, on the tribological behaviour of a fully formulated engine oil (FFEO) used for heavy-duty diesel engines by reciprocating a sliding tribometer, which simulated the tribological conditions of an engine cylinder liner and piston ring. We analysed the surface morphology, surface roughness, and elemental contents of countersurfaces through scanning electron microscopy/energy dispersant spectroscopy and surface roughness measurements. The wear mechanism was studied by analysing the compositions and kinematic viscosities of the oil samples. The results indicate that the friction coefficient increased along with the emulsified biomass fuel (EBF) content in FFEO. The wear mass loss and EBF content were simultaneously increased. The wear mechanism was mainly attributed to the corrosion function of the biofuel.

Utilization of Biomass to Ash: An Overview of the Potential Resources for Alternative Energy

Climate change and the potential depletion of fossil fuels have increased international demand for alternative and renewable energy sources. In terms of the energy sector, for example, most of the South-East Asian countries (SACs) have a large number of biomass sources due to their vast forest resources and agriculture-based economies. Thus, the critical review was aimed at highlighting the overview of biomass energy in South-East Asia as a dynamically developing region, in order to obtain economic and environmental benefits from the existing sources of biomass in the world. The current review analyzed the sources of biomass, as well as their energy potential, use, and management, based on reports from different countries, published studies, and scientific articles. In SAC, the main sources of biomass were found to be coconut residues, oil palm residues, sugar cane residues, rice straw, rice husks, wood waste, and firewood. The combined annual biomass potentials in the forestry and agricultural sectors in South-East Asia were approximately over 500 million tons per year and more than 8 gigajoule of total energy potentials. The study identified the challenges and barriers to using biomass in these countries to achieve sustainable use of biomass sources and recommended sustainable approaches to using biomass energy by comparing traditional uses of biomass. Smart grid technologies have ways for solutions for better electric power production and efficient ways for distribution and transmission of electricity. Smart grids require less space and can be more easily installed when compared to traditional grids because of their versatilities. Upcoming challenges include technology optimization for the following uses of biomass energy: direct combustion of woody biomass; pyrolysis and gasification of biomass; anaerobic digestion of organic waste to produce biogas; landfill gas production direct incineration of organic waste. The barriers in this technology are emissions of carbon and nitrogen oxides, unpleasant odors, as well as the uncontrolled harvesting of biomass, which can harm nature.

Smart Indoor Farms: Leveraging Technological Advancements to Power a Sustainable Agricultural Revolution

Conventional farming necessitates a large number of resources and infrastructure such as land, irrigation, manpower to manage farms, etc. Modern initiatives are required to automate conventional farms. Smart indoor farms offer the potential to remedy the shortfalls of conventional farms by providing a controlled, intelligent, and smart environment. This paper presents a three-dimensional perspective consisting of soilless farming, energy harvesting, and smart technologies, which could be considered as the three important characteristics of smart indoor farms. A six-layer smart indoor farms architecture has also been proposed, which explains how data are collected using various sensors and devices and then transmitted onto the cloud infrastructure for further analysis and control through various layers. Artificial lighting, smart nutrition management, and artificial climate control, to name a few, are some of the important requirements for smart indoor farms while considering control and service management factors. The major bottleneck in installing such systems is both the economical and the technical constraints. However, with the evolution of technology (and when they become widely available in the near future), a more favourable farming scenario may emerge. Furthermore, smart indoor farms could be viewed as a potential answer for meeting the demands of a sustainable agricultural revolution as we move closer to Agriculture 4.0. Finally, in order to adapt smart indoor farms and their study scope, our work has presented various research areas to potential researchers.

Thermal Analysis Technologies for Biomass Feedstocks: A State-of-the-Art Review

An effective analytical technique for biomass characterisation is inevitable for biomass utilisation in energy production. To improve biomass processing, various thermal conversion methods such as torrefaction, pyrolysis, combustion, hydrothermal liquefaction, and gasification have been widely used to improve biomass processing. Thermogravimetric analysers (TG) and gas chromatography (GC) are among the most fundamental analytical techniques utilised in biomass thermal analysis. Thus, GC and TG, in combination with MS, FTIR, or two-dimensional analysis, were used to examine the key parameters of biomass feedstock and increase the productivity of energy crops. We can also determine the optimal ratio for combining two separate biomass or coals during co-pyrolysis and co-gasification to achieve the best synergetic relationship. This review discusses thermochemical conversion processes such as torrefaction, combustion, hydrothermal liquefaction, pyrolysis, and gasification. Then, the thermochemical conversion of biomass using TG and GC is discussed in detail. The usual emphasis on the various applications of biomass or bacteria is also discussed in the comparison of the TG and GC. Finally, this study investigates the application of technologies for analysing the composition and developed gas from the thermochemical processing of biomass feedstocks.

GHG and NH3 Emissions vs. Energy Efficiency of Maize Production Technology: Evidence from Polish Farms; a Further Study

The paper determines the effect of selected cultivation technologies, including production chain energy inputs (growing, harvest, heap forming) on greenhouse gas emissions (GHGs) to the atmosphere. The data for the study was collected from 13 actually operating family farms ranging in size from 2 to 13 ha, located in the Podlaskie voivodship (Poland). GHG and ammonia (NH3) emissions from natural and mineral fertilisation as well as GHGs from energy carriers in a form of fuels (ON) were estimated. The average GHG emissions from the sources analysed were 1848.030 kg·CO2eq·ha−1 and 29.492 kg·CO2eq·t−1 of the green forage yield. The average NH3 emissions per hectare were 15,261.808 kg NH3 and 248.871 kg NH3·t−1 of yield. The strongest impact on the environment, due to the GHG emissions to the atmosphere, thus contributing to the greenhouse effect, is due nitrogen fertilisation, both mineral and natural. On average, in the technologies under study, 61% of the total GHG emissions came from fertilisation. The GHG emissions were correlated with the energy efficiency, calculated at the previous research stage, of the production technologies applied. There is a negative correlation (r = −0.80) between the features studied, which means that the higher the energy efficiency of the silage maize plantations, the lower the air pollution emissions in a form of the GHGs from the sources under study. It is so important to prevent environmental degradation to continue, conduct in-depth, interdisciplinary research on reducing the energy consumption of crop production technologies and striving to increase energy efficiency.

Spanish Poplar Biomass as a Precursor for Nanocellulose Extraction

The effect of acidic hydrolysis duration on nanocellulose size, morphology, and proper ties was investigated, which opens up a whole new horizon of versatility in poplar applications. This study aimed to examine Spanish poplar wastes as raw material to extract crystalline nanocellulose (CNC), which substantiates the importance of poplar wastes. Wastes were pulped using 1 L of 10% NaOH (wt./wt.) solution, and bleached several times by NaClO2; afterwards, white wastes were subjected to acidic hydrolysis by 60% H2SO4 for either 5, 10, or 15 min. Microcrystalline cellulose (MCC) underwent a similar hydrolysis protocol as poplar as control. TEM, IR, and XRD characterization techniques were performed. Poplar based nanocellulose sized 219 nm length and 69 nm width after 15 min acidic hydrolysis. MCC yielded 122 nm length and 12 nm width crystals after 10 min acidic hydrolysis. Hydrolysis resulted in a drastic change and intense peaks at 3500 and 2900 cm−1 for nanocellulose. Although pre-hydrolysis fiber treatment was not influencial on the crystallinity of poplar, acidic hydrolysis remarkably raised the crystallinity index (CI) by 7–8%. The more hydrolysis duration was prolonged, the size of the resulting crystal (whisker) decreased, and the aspect ratio increased. Hydrolysis was more impactful on MCC than poplar. However, for future work, it seems that longer duration of pulping and bleaching could have significantly removed unwanted components (hemicellulose and lignin), showcased in IR and XRD, and hence smoothened the following hydrolysis.

Evaluation and Characterization of Timber Residues of Pinus spp. as an Energy Resource for the Production of Solid Biofuels in an Indigenous Community in Mexico

This study shows the energy potential of pine wood waste for the production of solid biofuels, and was carried out in an indigenous community in the state of Michoacán. One of the main economic activities of this community is the production of handcrafted furniture, which generates a large amount of wood waste. The most relevant results obtained in this research show that the community generates approximately 2268 kg of sawdust and 5418 kg of shavings per week, and the estimated energy potential per year for both sawdust is 1.94 PJ and for shaving is 4.65 PJ. Based on the particle size observed, the wood residue can be used to generate pellets or briquettes. Other average results in sawdust and (shavings) are the following: initial moisture content 15.3% (16.8%), apparent density 169.23 kg/m3 (49.25 kg/m3), ash 0.43% (0.42%), volatile material 84.9% (83.60%), fixed carbon 14.65% (15.96%), hemicelluloses 12.89% (10.68%), cellulose 52.68% (52.82%), lignin 26.73% (25.98%), extractives 7.69% (10.51%), calorific value 17.6 MJ/kg (17.9 MJ/kg). The major chemical elements in the ash were Al, K. Fe, Ca, P, Na, and Mg. Finally, the results obtained indicate that this biomass can be used to generate pellets or briquettes in this indigenous community.

Influence of INGER and TORDIS Energetic Willow Clones Planted on Contaminated Soil on the Survival Rates, Yields and Calorific Value

The paper presents some forestry aspects of using Inger and Tordis willow clones to obtain woody biomass and remedy degraded soils. The methodological aspects regarding the planting of willow seedlings, the evaluation of the survival rate, the evaluation of the biomass quantity and the enrichment of the soil are analyzed. The results of the experiments showed that the degraded soil decreased the viability rate of the cuttings by 16.6% for the Tordis clone and 35.8 for the Inger clone. The analysis of the soil samples showed that it was enriched in nutrients after 2 years of cultivation, by the decomposition of the fallen leaves on the soil and by the absorption of the substances from the soil. Regarding the amount of biomass, its mass per hectare after the first year of cultivation was 0.64 t/ha for the Inger clone and 0.66 t/ha for the Tordis clone, while the calorific values of 19,376 kJ/kg for Inger and 19,355 kJ/kg for Tordis were good values. The final conclusion of the paper highlights that Osier willow is a viable solution for obtaining energetic biomass and putting it back into the productive circuit of degraded soils.

Evaluation of Mechanical and Energetic Properties of the Forest Residues Shredded Chips during Briquetting Process

The briquetting process is one of methods of solid biofuel production. During the briquetting of raw material, it can be noticed that material is viscoelastic, and reflects the effect on the volume and the final effect of the agglomerate during mentioned treatment. The research aimed to evaluate the mechanical and energetic properties of shredded pine forest residues during the briquetting process. The shredded fragments of the forest residues were compacted by the principal stresses with determination of the energy value consumed during the briquetting process. Tests were carried out using a specially designed compacting tube, with additional equipment directly mounted on the testing machine. The compaction process was carried out using the presented material and through continuous monitoring of the process parameters. During the study, it was estimated that the moisture content of the compacted material should be equal from 10 to 15%. The calculated average value of the unit energy consumption during the briquetting process (WB) was equal to 0.14 MJ·kg−1. In future research, the mathematical model can serve as an algorithm in a computer program in order to calculate the flow of biomass in the extrusion process.

An experimental study of sunflower husk pellets combustion

The thermogravimetric study of the sunflower husk pellets combustion was carried out at three heating rates: 5, 10, and 20 °C/min to increase the efficiency of agricultural waste disposal methods. The husk combustion process can be divided into several stages: the stage of moisture evaporation and the release of light fractions of volatile substances, the main stage of the release of volatiles and combustion, as well as the stage of the carbonaceous residue after-burning. The maximum mass loss was observed in the experiment with a heating rate of 10 °C/min, and it was equal to 91.99% of the total weight of organic matter. The average residual mass for all experiments was 3%. The higher heating value (HHV) of sunflower husk pellets was 19.2 MJ/kg. When implementing a biomass boiler with a capacity of 430 kW, the return period will be 3.43 years.