Biomass Pellets Research Articles

Application of computational fluid dynamics and response surface methodology in downdraft gasification using multiple biomass pellets

Downdraft gasifier is a promising technology converting biomass into synthesis gas (syngas) for decentralized heat and power generation. As biomass is seasonal variation and diversity, the design of the gasifier should consider a variety of biomass feedstock. This study investigated a single-designed downdraft gasifier of different biomass pellets using computational fluid dynamics and optimized for producer gas quality and gasifier efficiencies. Three biomass pellets, i.e., wood, bagasse, and palm-oil empty fruit bunch (PEFB), were considered the primary qualitative variable in addition to the main process variables, i.e., air-inlet temperature and equivalence ratio (ER). Response surface methodology (RSM) and multi-objective genetic algorithm (MOGA) were carried out for process and biomass optimization. Tar yield is considered a response for optimization along with carbon conversion (CCE) and cold gas efficiencies (CGE). The results showed that ER and biomass type are crucial. The range of ER for each biomass should be carefully selected. The maximum efficiencies of the gasifier can be achieved using PEFB pellets, whereas the minimum tar yield was attained using wood pellets. The CCE and CGE of 93.11% and 65.16%, respectively, and the tar yield of 12.36 mg Nm−3, were obtained at an optimum ER of 0.28 and air-inlet temperature of 1272.8 K using PEFB pellets.

Biomass for dual-fuel syngas diesel power plants. Part I: The effect of preheating on characteristics of the syngas gasification of municipal solid waste and wood pellets

Indonesia has the potential to develop biomass, such as MSW and wood pellets, as a source of energy. Syngas from biomass gasification can be used as fuel for dual-fuel diesel engines in order to transition energy. We investigated the gasification of MSW and wood pellets using a downdraft reactor with a capacity of 130–144 kg in order to determine the properties of the produced syngas for use in dual-fuel syngas diesel engines. Four days are dedicated to the process of preheating biomass with sunlight. The experiment was designed with an equivalent ratio of 0.22 and an oxidation zone temperature between 700 and 900 degrees Celsius. According to the experimental results, the average lower heating value of syngas produced by the air gasification of MSW biomass was 5.85 MJ/Nm3, the cold gas efficiency was 56.6%, and the carbon conversion efficiency was 94.77%. The average lower heating value from wood pellet biomass air gasification was 5.95 MJ/Nm3, the cold gas efficiency was 67.7%, and the carbon conversion efficiency was 94.28%. Solar heating of biomass has been shown to increase the calorific value of biomass gasification to syngas.

Design and control concept of a 1 MWth chemical looping gasifier allowing for efficient autothermal syngas production

Chemical looping gasification (CLG) is a novel gasification concept, allowing for the efficient production of a high calorific, N₂-free syngas with low tar content. Previous studies showed that the inherent process characteristics require a dedicated process control concept in order to allow for sufficient solid and thus heat transport between the two reactors (air and fuel reactor) of the gasification unit, while at the same time being able to accurately tailor the air-to-fuel equivalence ratio (λ), thus obtaining stable gasification conditions. To demonstrate its viability, a suitable control concept was implemented in the 1 MWth modular pilot plant located at the Technical University Darmstadt. In this paper, results obtained during the first ever autothermal CLG operation, achieved in this unit using biomass pellets as the feedstock, are presented, highlighting important process fundamentals. It is demonstrated that the novel process control concept allows for an accurate control of λ in semi-industrial scale, while at the same time guaranteeing stable hydrodynamics and thus solid and heat transport between the air and fuel reactor, making it a suitable control concept for large-scale implementation. Moreover, it is demonstrated that the underlying phenomena of the CLG process lead to substantial system inertia, as the solid bed inventory of the gasifier acts as an oxygen storage during transient periods, evoked by changes in the air-to-fuel equivalence ratio.

Effect of pelleting on the enzymatic digestibility of corn stover

Pelleting of lignocellulosic biomass to improve its transportation, storage and handling impacts subsequent processing and conversion. This work reports the role of high moisture pelleting in the enzymatic digestibility of corn stover prior to pretreatment, together with associated substrate characteristics. Pelleting increases the digestibility of unpretreated corn stover, from 8.2 to 15.5% glucan conversion, at 5% solid loading using 1 FPU Cellic® CTec2 per g solids. Compositional analysis indicates that loose and pelleted corn stover have similar non-dissolvable compositions, although their extractives are different. Enzymatic hydrolysis of corn stover after size reduction to normalize particle sizes and removal of extractives confirms that pelleting improves corn stover digestibility. Such differences may be explained by the decreased particle size, improved substrate accessibility, and hydrolysis of cross-linking structures induced by pelleting. These findings are useful for the development of processing schemes for sustainable and efficient use of lignocellulose.

Optimal composition of biomass pellet for enhancing calorific value using MOGA-ANN: a mixture of paddy straw, sawdust, cow dung, and paper pulp

Optimal composition of biomass pellet for enhancing calorific value using MOGA-ANN: a mixture of paddy straw, sawdust, cow dung, and paper pulp

STUDY OF THE APPLICATION OF PELLETS FROM TEXTILE MATERIAL WASTE AND BIOMASS MIXTURE IN INDUSTRIAL AND RESIDENTAL HEATING SYSTEMS

The efficient waste management hierarchy is based on four priorities, reuse, recycle, energy recovery, deposit.Efficient energy recovery from non-recyclable textile materials (waste to energy) principles we study in this paper. Energy recovery from the fuel pellets consisting of waste textile materials and biomass depends on many factors. One of the main is to create a competitive form for the newly offered fuel (pellets from a mixture of biomass and textile), as well using a new generation of small-scale energy production facilities. Using already existing applications for efficient waste management is one of the circular economy aspects we lay on in this paper.Roughly estimated that the quantities of textiles separately collected will increased from 65 000 to 90 000 tons per year across the EU-27 from 2025. Reuse and recycling outlets will need to be created, as the current sorting and recycling capacities are not sufficient to process the anticipated volumes. However, it is also expected that at least half of these additional volumes will comprise non-reusable textile waste with specific flame retardant (FR) treatment. It is known that flame retardant is hazard by its adverse environmental impacts of FRs in their production and disposal phases.The objective of the paper is to review opportunities of elaboration a new type of the fuel pellets, and using them in industrial heat pellet boilers and combined heat and power CHP systems.Elaborated the new pellets from biomass (prepared by plasticization method) and chopped textile waste sized till 2-3 mm (by method separative milling) were tested in controlled combustion processes.Experiments were carried out by adding different proportions of textile waste to biomass pellets and the results obtained are summarized in the article

Effect of pretreatment parameters and binder concentration on the densification of wood residue

AbstractPakistan is a farming and agricultural country facing energy issues from many years due to an increase in population and lack of technological development. Biomass is usually considered a waste. It is a major renewable energy source that is abundantly present in Pakistan. The wood residue is one of the potential biomasses to be used for energy purposes. Wood residue densification is considered a source of energy in this article. The effect of different pretreatments and binders (natural and synthetic) concentrations (5%, 10%, and 15%) on the densification of wood residue are analyzed. In addition to this, densified biomass pellets are characterized by physical, mechanical, thermal, and structural properties. The results indicated that densified pellets with 5% natural binder (rice binder) are found to be better in physical, mechanical, and thermal properties (IRI = 316, HV = 5396.3 Cal/g). The durability of the pellets with binder concentration is found to be linked with the bonding characteristics. It shows insights into the use of different biomass materials for energy generation to fulfill the demands of increasing commercialization and population. It indicates future prospects for better access to energy, reliable quality of air, and security of energy simultaneously while avoiding the harmful effects of climate change.

Evolution of biomass particles during pelletization process

Pulverizing is an essential unit operation in co-firing biomass with coal. Pulverizers are only compatible with pellet forms of fibrous biomass materials and crush them down to their original forming particle sizes. That is why the data on the size distribution of the particles forming a biomass pellet is crucial to achieving optimum combustion conditions. The current study determines the internal particle size distribution of pellets after wet disintegration, following ISO 17830 standard, and aims to suggest improvements to the mentioned standard based on new measured evidence. Experiments were carried out on white wood pellets (no bark) and brown wood pellets containing bark at four water temperatures: 20, 40, 60, and 95 °C, with or without stirring. The particle size distribution of the pre-pelletizer wood particles was also measured and compared with particles in the formed pellets. Ambient water temperature of 20 °C was found to be adequate for the complete disintegration of pellets, and no mechanical stirring was required. About 30% of particles in the disintegrated pellets were 0.5–1.0 mm. Pelletization changes the particle size distribution to smaller particles. The disintegrated bark pellets contained more fines than white pellets.

Road widening in west Papua: A design and economic feasibility analysis of urban green infrastructure

Planned road expansion in Manokwari, West Papua, along 6.5 km of the Maruni - - Dr. Esau Sesa in phase I of 2024 will prioritize low-carbon development and climate resilience. Road design enhancement and economic and financial analysis are conducted in this research. In the economic analysis, the National Road Administration Agency, the Head of Public Works and Spatial Planning, and the Regional Development Planning Agency from the regency and provincial collaborated on budget tagging. The proposed design incorporates bicycle lanes, green infrastructure in tree-based pedestrian areas as an energy source for biomass pellets, solar panel-based street lights, drainage along pedestrians to anticipate extreme weather and flooding, rehabilitation of mangroves whose ecosystem function has diminished, and retaining buildings erosion for damaged mangroves. The economic analysis begins with the calculation of the Vehicle Operating Cost (VOC) for large cities using the ratios 1:7 (Light Vehicle, LV) and 1:4 (Heavy Vehicle, HV). Time savings of up to 10 minutes and total VOC contribute to the total savings. Furthermore, an analysis of NPV > 0, IRR > 15%, BEP in the fifth and sixth year, and net B/C ratio > 0 indicates that road improvement is feasible based on economic analysis.

Comparison Moisture of Biopellet from Sugarcane Bagasse and Coconut Dregs as Raw Materials for Co-Firing Power Plant

This study investigated the use of locally-grown sugarcane bagasse and coconut dregs as raw materials for producing biomass pellets, which can be burned in the coarse form to generate heat energy. The proximate properties, such as moisture content, of the fuel pellets produced from sugarcane bagasse and coconut dregs were analyzed to determine the performance of the pelletizer equipment used in producing the biomass pellets. Moisture content was measured to evaluate the fuel pellet properties of the bagasse and coconut biomass and to, determine their durability and optimize the performance of the pelletizer equipment. The ideal pelleting moisture values for sugarcane bagasse and coconut dregs were found to be under 10%. In general, the physical and chemical properties of coconut biomass pellets were within the recommended limits. However, the pellets exhibited a relatively high ash level compared to wood biomass.

Biomass pellet fueled chemical looping gasification: Reaction kinetics study with a fluidized bed - thermogravimetric analysis

Biomass pellets show the advantages of higher energy density, lower transportation and storage costs compared to powder biomass, making them attractive for future industrial applications. In this work, a fluidized bed-thermogravimetric analysis (FB-TGA) is developed. The gas-solid process for gram-scale biomass pellets under fluidization state at high temperature is characterized. The effects of gasification agents, bed material components and operating conditions on devolatilization and char gasification are investigated. The devolatilization is revealed to be a rapid phase transition process of volatiles, of which the rate is mainly affected by the intense heat and mass transfer with increasing temperature. While the char gasification is significantly slower, taking more than 600 s for all conditions, therefore be considered as the rate-control step. The hematite oxygen carrier can effectively promote the char gasification by breaking the concentration balance of gas components near the char surface. The char reaction kinetics is fitted based on the isothermal differential method. Results show that the cylindrical geometrical contraction model exhibits an excellent linear correlation. With a mass ratio of oxygen carrier/quartz sand of 1:9, the average activation energies of 130.58 kJ/mol and 104.17 kJ/mol are obtained when CO2 and steam as gasifying agents.

Biomass Fuel Production through Fermentation of Lysinibacillus sp. LC 556247 in Various Ratios of Palm Oil Mill Effluent and Empty Fruit Bunch

Biomass wastes originating from palm oil milling activities can be characterized by their high biochemical oxygen demand (BOD), chemical oxygen demand (COD), total suspended solid (TSS), and oil and grease content. The utilization of oil palm wastes such as palm oil mill effluent (POME) and empty fruit bunch (EFB) has great potential for a sustainable energy biomass pellet as it reduces the reliance on conventional materials for energy production. A mixture of POME and EFB in various ratios ranging between 7:3, 8:2, 9:1, and 10:0 was fermented in the presence of Lysinibacillus sp. LC 556247 for 120 h at 37 ± 2 °C and 180 rpm with the aim of elucidating the biodegradation of complex organic material in terms of BOD, COD, TSS, total organic carbon, inorganic carbon, and total carbon content. After fermentation, the mixtures were oven dried at 105 °C overnight and then subjected to calorific energy value (CEV) determination. The highest CEV of 20.26 MJ/kg was achieved for a ratio of 10:0 (slightly higher than the control experiment with the value of 18.67 MJ/kg), with maximum removal efficiencies of COD (12.19%), BOD (11.72%), TSS (93.94%), and oil reduction of 17.43%. The addition of EFB did not positively increase the CEV.

Hybrid sol-gel coatings for reducing wettability and storage degradation of biomass pellets

Long transport distances and extended storage of biomass pellets especially in humid environments provide a suitable setting for enhanced degradation in the form of moisture sorption, cracking and attrition. We developed an optically transparent, low-cost and environmentally friendly coating to reduce moisture sorption and storage degradation of pellets. The developed coating is a hybrid sol–gel, based on tetraethoxysilane (TEOS) and 3-glycidoxypropyl-trimethoxysilane (GPTMS) precursors. We coated two types of untreated and one type of torrefied wood pellets and stored them in a climate chamber during 1 month simulating a ship's hold, at a constant condition of 40 °C and 85% relative humidity. After 1 month of storage, the mean water contact angle increased by a factor of two compared to the uncoated ones. The lower wettability of the sol-gel coated untreated pellets compared to the non-coated torrefied pellets might provide an alternative to torrefaction.

Influence of oscillating water content on the structure of biomass pellets

When handling wood pellets, the main challenge arises during storage, where the physical properties of the pellets are affected by fluctuating relative humidity (RH). With increasing RH, the water content of the pellets increases, which leads to swelling and higher porosity as well as crack formation on the surface. However, these changes are reversible to a certain extent and the pellets can recover fully or to a certain extent when the RH subsequently decreases again. The permanent damage caused by fluctuating RH is shown in the form of larger gaps between the wood chips within the pellets. As a result, the pellets have a larger volume and higher porosity as well as higher surface roughness than in their initial state before storage. In particular, when the saturation vapor pressure was exceeded to reach a water content of over 12 wt.-%, the reversibility of the structural changes appeared to be lower.

Interpreting Highly Variable Indoor PM2.5 in Rural North China Using Machine Learning.

Household air pollution associated with solid fuel use is a long-standing public concern. The global population mainly using solid fuels for cooking remains large. Besides cooking, large amounts of coal and biomass fuels are burned for space heating during cold seasons in many regions. In this study, a wintertime multiple-region field campaign was carried out in north China to evaluate indoor PM2.5 variations. With hourly resolved data from ∼1600 households, key influencing factors of indoor PM2.5 were identified from a machine learning approach, and a random forest regression (RFR) model was further developed to quantitatively assess the impacts of household energy transition on indoor PM2.5. The indoor PM2.5 concentration averaged at 120 μg/m3 but ranged from 16 to ∼400 μg/m3. Indoor PM2.5 was ∼60% lower in families using clean heating approaches compared to those burning traditional coal or biomass fuels. The RFR model had a good performance (R2 = 0.85), and the interpretation was consistent with the field observation. A transition to clean coals or biomass pellets can reduce indoor PM2.5 by 20%, and further switching to clean modern energies would reduce it an additional 30%, suggesting many significant benefits in promoting clean transitions in household heating activities.

Pelletization Temperature and Pressure Effects on the Mechanical Properties of Khaya senegalensis Biomass Energy Pellets

Biomass pellets are one of the most crucial feedstocks for bioenergy production on a global scale due to their numerous advantages over raw biomass resources. Pellets provide improved energy density, bulk density, moisture content, and homogeneity thereby reducing storage, handling, and transportation costs. To produce high-quality solid fuel, it is necessary to comprehend the properties of wood fuel. This study explored the potential of Khaya senegalensis (khaya) as a dedicated energy crop (DEC) for the production of green energy. It thrives in less-than-ideal conditions and grows rapidly. The low durability of energy pellets raises the risk of dust and fire during handling and storage. In addition, the potential for fines and dust formation is strongly correlated with the mechanical strength of materials. Due to this necessity, the current study examines the effects of pelletization factors, including temperature and pressure, on pellet properties, particularly on its mechanical properties. The durability and compressive strength of pellets were determined using a sieve shaker and a universal testing machine, respectively. The highest mechanical durability was observed at 3 tons of pressure and 75 degrees Celsius, each with a value of 99.6%. The maximum axial compressive strength was measured at 57.53 MPa under 5 tons of pressure. When pelletized at 125 °C, the axial compressive strength increased by 13.8037% to 66.06 MPa compared to the strength obtained at 5 tons of pressure. Pelletizing Khaya feedstocks at 4 tons of pressure, on the other hand, produced a slightly lower diametral compressive strength of 7.08 MPa compared to 7.59 MPa at 125 °C. The experimental results revealed that the aforementioned factors significantly affect the mechanical properties of pellets. The elucidation of wood biomass, solid fuel qualities and pelletization parameters of this potential energy crop may facilitate the production of high-quality pellets from Khaya senegalensis wood to meet the increasing local and worldwide energy demands.

Effect of Moisture Content and Particle Size on Characteristics of Fuel Pellets Using Flat Die Type Pelleting Machine

Fuel pellets are a popular form of biomass energy due to their high energy density, ease of handling, and reduced emissions. The quality of fuel pellets is influenced by various factors, including the moisture content and particle size of the raw materials (Soybean straw and cotton stalk) used during the pelletization process. In this study, the effect of moisture content and particle size on the characteristics of fuel pellets produced using a flat die type pelleting machine was investigated. Different moisture content levels (ranging from 20 to 30%) and particle sizes (ranging from 4 to 8 mm) were used to pelletize a biomass feedstock. The pellet characteristics, including pellet durability, bulk density and water resistance and energy consumption were evaluated. The results showed that both moisture content and particle size significantly influenced the characteristics of the fuel pellets as well as energy consumption. Based on the findings, an optimal moisture content of 25% and particle size of 6 mm were determined for producing fuel pellets with desirable characteristics and low energy consumption was required using the flat die type pelleting machine. These results can provide valuable insights for biomass pellet producers and researchers in optimizing the pelletization process to achieve high-quality fuel pellets with improved properties.

Pelletization Process for the Production of Fuel Pellets from Various Surplus Biomass: A Review

The increasing demand for renewable and sustainable energy sources has led to a growing interest in utilizing surplus biomass for the production of fuel pellets. Pelletization is a promising process that converts biomass into compact and uniform fuel pellets, which can be used as an alternative to fossil fuels. Biomass is an important renewable energy source, and surplus biomass can be used to produce fuel pellets. The review also discusses the different types of biomass feedstocks that can be used for pelletization, including their availability, properties, and suitability for pellet production. The review further delves into the pelletization process, covering the key steps, such as size reduction, drying, conditioning, pelletization, and cooling. The influence of process parameters on pellet quality, including pellet durability, density, moisture content, and energy content, is also discussed in detail. The information presented in this review can serve as a valuable resource for researchers, engineers, and policymakers interested in biomass pelletization for renewable energy production.

Thermogravimetric assessment for combustion characteristic of torrefied pellet biomass from agricultural solid waste

This present paper is focused on the investigation of combustion characteristics of torrefied pellet biomass from agricultural waste. Four biomass pellet samples such as sugarcane bagasse, Napier grass, Palm Empty Fruit Bunches, and Cassava stem were torrefied in a designed cylinder tubular pyrolysis reactor. The reactor was set up under 30 min of residence time, and the temperature reaction was varied at 200, 250, and 300 °C in an inert atmosphere. The torrefied products were then characterized in terms of their psychochemical properties such as proximate, ultimate, calorific value, and combustion properties. The combustion properties of raw and torrefied biomass pellets during the combustion process were investigated by the thermogravimetric analyzer Exstar SII TG/DTA7300. The samples were heated at an ambient temperature up to 800 °C at a constant heating rate of airflow at 10 °C/min in airflow. The results showed that the moisture content and volatile matter of torrefied pellets decreased by 2 to 5% and 8 to 14%, subsequently. Otherwise, the fixed carbon content is up to three times higher than the raw material. The study conclusively that torrefaction can also able to enhance combustion performance in terms of ignition and burnout temperature, ignition and burnout index, and combustion rate. The results shows that, the ignition and burnout temperatures of torrefied pellets are higher than raw material. The ignition and combustion index of torrefied pellets are lower than raw material, and the torrefied pellets have a longer burning time and a higher combustion temperature.

Algae Pyrolysis in Molten NaOH-Na2CO3 for Hydrogen Production.

Biomass pyrolysis within the alkaline molten salt is attractive due to its ability to achieve high hydrogen yield under relatively mild conditions. However, poor contact between biomass, especially the biomass pellet, and hydroxide during the slow heating process, as well as low reaction temperatures, become key factors limiting the hydrogen production. To address these challenges, fast pyrolysis of the algae pellet in molten NaOH-Na2CO3 was conducted at 550, 650, and 750 °C. Algae were chosen as feedstock for their high photosynthetic efficiency and growth rate, and the concept of coupling molten salt with concentrated solar energy was proposed to address the issue of high energy consumption at high temperatures. At 750 °C, the pollutant gases containing Cl and S were completely removed, and the HCN removal rate reached 44.92%. During the continuous pyrolysis process, after a slight increase, the hydrogen yield remained stable at 71.48 mmol/g-algae and constituted 86.10% of the gas products, and a minimum theoretical hydrogen production efficiency of algae can reach 84.86%. Most importantly, the evolution of physicochemical properties of molten NaOH-Na2CO3 was revealed for the first time. Combined with the conversion characteristics of feedstock and gas products, this study provides practical guidance for large-scale application of molten salt including feedstock, operation parameters, and post-treatment process.