Biomass Blends Research Articles

Enhancing the fuel properties of beverage wastes as non-edible feedstock for biofuel production

A few industries, such as the beverage industry, have experienced some growth in sales during the COVID-19 pandemic. Globally, beverage companies alone generate over 200 million tonnes of biomass annually, which largely ends up as animal feed or in landfills. With the UK government’s commitment to reduce its carbon footprint by at least 68% in 2030, many companies, especially small and medium enterprises (SMEs), are exploring options to reduce carbon emissions and develop roadmaps to become carbon neutral. It has thus become imperative for beverage companies to find value in or repurpose their waste. This paper unlocks the potential for improving the fuel properties of beverage waste through a blending process and explores the determination of optimal fractions for the blends via characterization. With an initial moisture content of 82 and 58 wt.% brewery spent grain (BSG) and spent coffee grounds (SCG), respectively, the pre-treatment process reduced moisture content by approximately 10–15 wt.%. The study concludes that biomass blending improved the fuel properties of the biomass, providing a competitive comparison with coal for energy applications.

Gasification investigations of coal and biomass blends for high purity H2 production with carbon capture potential

Biomass is carbon-neutral and has the carbon-negative potential if combined with carbon capture and storage (CCS). This study investigated the thermochemical conversion to high-purity hydrogen of a typical lignite (BYH) and seaweed biomass (BS) with carbon capture in a designed fixed-bed reactor at moderate conditions (1atm, 873K). High-purity hydrogen of 486.91–801.5ml/g-blends with suppressed CO2 formation was produced in the alkaline gasification. The alkali can decompose the coal/biomass molecular structures, in-situ capture CO2 and control the gases to high-purity H2 (80.1%–93.2%). The synergistic effect of coal and biomass changes the gas evolution behaviors and impacts the chemical structures of the char. The abundant SiO2 and Al2O3 in the coal can inhibit the catalytic activities of earth alkali metals in the biomass, but not much. These results are significant to the future development of low-carbon renewable energy techniques.

Investigation of co-pyrolysis characteristics of high-ash Indian coal and rice husk

This study investigates the non-isothermal pyrolysis characteristics of a low-grade, high ash Indian coal, and rice husk using a thermogravimetric analyzer (TGA). A series of thermo-gravimetric experiments are conducted to examine the effects of coal and biomass blending on their thermal degradation behavior and synergetic effects in the nitrogen atmosphere. The thermo-gravimetric (TG) curves show two distinct tips where the larger tip is obtained for biomass as compared to the coal. The thermogravimetric study does not demonstrate any significant synergetic interaction between the biomass and high ash coal in the blends, and the additive rule describes the behavior of their combined pyrolysis. The activation energy and preexponential factor for coal and biomass are calculated based on the TGA data using the Friedman method. the corresponding calculated mean activation energy values for the biomass and Indian low-rank coal were found to be 203.463 KJ/mol, and 66.97 KJ/mol respectively.

TG-DSC investigation of co-combustion characteristics of blends sawdust and coal

Co-combustion of biomass and coal in coal fired power plant could reduce CO2 emissions and utilize renewable energy resources. To understand the co-combustion characteristics of biomass and coal blends, thermogravimetry-differential scanning calorimetry (TG-DSC) analysis, as well as proximate, ultimate and heating value have been conducted. TG-DSC measures both weight changes (TG) and heat flow (DSC) in a material as a function of temperature or time in a controlled atmosphere. The combustion profiles can be used to study some combustion properties of fuels and fuel blends. The biomass that used in this study was sawdust in its origin and torrefied sawdust which blend with a low rank coal. The composition of the biomass and coal were 1:3; 1:1 and 3:1 in weight ratio. Results indicated that the blend of coal and torrefied sawdust in weight ratio of 1:3 was the best combustion performance compared to the other composition, indicated by the highest of ignition temperature (Tig), maximum combustion rate (Rmax) and heating value.

Co-Combustion of Blends of Coal and Underutilised Biomass Residues for Environmental Friendly Electrical Energy Production

This study investigated the co-combustion of the blends of coal and biomass residues from poplar sawdust, rice husk, pine nut shells, and sunflower residues for ecofriendly energy production. Proximate and ultimate analyses and calorific values of the coal and biomass residues were also carried out to evaluate the properties of the coal and biomass residues. The volatile matter in coal was reported as 43.38 wt% and ranged from 56.76 wt% to 80.95 wt% in the biomass residues. The ultimate analysis reported the carbon and sulfur content of coal as 68.7 wt% and 5.5 wt%, respectively. The coal and biomass blends were prepared using different ratios on the thermal basis of coal and biomass given as 100:0, 90:10, 80:20, 70:30, 60:40, and 50:50 by weight percentage. The consequent stoichiometric air requirements for all the blends were also calculated. The results revealed that the combustion of 60:40 of coal and sunflower residue blend was the most efficient blend, resulting in less emission of NOx, SOx, and CO2 in the flue gas compared to the combustion of pure coal. The study revealed a great perspective of the selected biomass residues to blend with coal for environmentally friendly and sustainable energy production.

Experimental Study and Design of Biomass Co-Firing in a Full-Scale Coal-Fired Furnace with Storage Pulverizing System

Co-firing coal and biomass in existing power plants facilitates influential advancement in the use of renewable energy resources and carbon emissions reduction. Biomass is intended as a CO2-zero net emission because, during its rise, it uses the same fraction of CO2 from the air as that released during its combustion. In addition, the content of nitrogen and sulfur in biomass is lower than in coal. Therefore, the emissions of NOx and SOx can be minimized by co-firing it with coal. In general, the effect of biomass direct co-firing on safety, pulverizing system performance, furnace efficiency, and NOx emission in full-scale furnaces is rarely studied. In this study, biomass direct co-firing was carried out in a 55 MW tangentially fired pulverized coal furnace. The effects of biomass co-firing on safety, the performance of the pulverizing system, furnace efficiency, and pollutant emissions (unburned carbon and NOx) are studied. The results show that the blending of biomass fuel with less than 20% of coal has no issue with respect to auto-ignition and safety. The performance of the pulverizing system is affected up to a certain limit due to the difficulty of grinding the biomass particles into required fineness. The biomass co-firing up to 20% is feasible, but greater than this percentage will severely affect the furnace efficiency. The co-firing of biomass enhanced the NOx reduction significantly and further improved the performance of the SNCR process. This study could provide guidance for the application of biomass co-firing in industrial furnaces.

Combustion behavior and mechanical properties of pellets derived from blends of animal manure and lignocellulosic biomass

This paper presents the possibility of valorization of animal manure (camel and cow) by mixing it with agro-industrial biomass (cotton stalk and rapeseed oil cake) to produce pellets for use in power generation processes. Feedstocks were mixed in specific proportions based on certain assumptions concerning the energy and mechanical parameters of pellets. The assessment concerned both the combustion behavior as well as mechanical properties of four types of pellets derived from blends of animal manure and agro-industrial biomass.Thermogravimetry (TGA) and Differential Scanning Calorimetry (DSC) techniques are applied to analyze the reaction areas, characteristic temperatures as well as heat flow rates of raw materials and their blends. Results showed that addition of agro-industrial biomass (even 10%) to animal manure changed the specific combustion parameters: initiation and burn-out temperature and combustion time. For blends of cow manure (COM) and rapeseed oil cake (ROC), a reduction in the initiation temperature was achieved compared to the combustion of raw cow manure, and the combustion time increased by 1/3. In the case of camel manure (CAM) with the addition of cotton stalk (CS) the burn-out temperature and combustion time decreased.The addition of agro-biomass also causes a change in the heat release profiles, for the blends no pronounced DSC peaks are obtained in the area of devolatilization as it happens animal manure alone and in the area of fixed carbon combustion as for cotton stalk and rapeseed oil cake. The heat released from camel manure blends was 9.2–9.3 kJ/kg and from cow manure blends 10.2–10.4 kJ/kg.An evaluation of the physical and mechanical properties showed that all types of pellets at a moisture content of 10–15% have a similar drop strength in the range of 80–85%, while this strength decreases to 40–60% after the pellets have absorbed water.

Wet oxy-combustion of blends of coal and biomass

Oxy-fuel combustion of blends of coal and biomass has been experimentally investigated, largely replacing CO2 with H2O as temperature moderator in the firing atmosphere. The novel concept of the so-called oxy-steam combustion, i.e. combustion in O2/H2O atmospheres, merges the advantages of reducing auxiliary consumptions and lowering air in-leakages. Two blends of coal and biomass have been tested, in 80:20 mass ratio. Forestry wood residues from pine and raw residues from vineyard pruning have been selected. The experiments have been carried out in lab-scale electrically-heated entrained flow reactor for a set of O2/CO2 and O2/CO2/H2O atmospheres, with steam contents up to 40 % and oxygen contents up to 35%. When 20% of coal is substituted with biomass, fuel conversion rates increase and NO formation rates decrease, with a different extent depending on the biomass type. The higher volatile and lower nitrogen contents of the biomass determine that observation. As regards the effect of CO2 replacement by H2O, it can be observed that particular steam concentrations lead to the maximum fuel conversion and the minimum NO formation rates. This behavior is related to the effects of steam when replacing carbon dioxide: increase of flame temperature, oxidant diffusivity and char gasification, as well as active participation in NOx reduction mechanisms in the gas-phase.

Influence of composition and compaction pressure on the physical quality of wood residue and bottom ash mixture briquettes

Woody biomass is briquette-densified to enhance its physical and mechanical properties during handling and storage. However, Limited study on the physical consistency of briquettes made from wood biomass and bottom ash blends has been carried out. The bottom ash used in this study is a residue from burning coal for the powerplant. The physical quality was evaluated for three different compositions (70:30, 50:50, and 30:70). The piston press type machine (laboratory scale) was employed to produce a briquette. This work aims to evaluated the effect of mixing ratio (wood residue and bottom ash) and compaction pressure on the physical quality (water content, ash content, VM, calorific value) and combustion behavior. The compaction pressure was varied between 100 kg/cm 2 and 150 kg/cm 2. The result revealed that the compaction pressure affected the physical quality of the briquette. Lower moisture content (MC), ash content (AC), and calorific value (CV) were obtained at the higher compaction pressure. The moisture content of 1.6% was better for the wood residue and bottom ash mixture’s compaction pressure. The calorific value of briquette ranged from 5200 kal/g to 5700 kal/g. In conclusion, the combination of low-cost and abundant forest biomass mixed bottom ash available with wood biomass could lead to better physical quality and help meet the demand for the briquette in the future.

Electrospun Carbon Nanofibers from Biomass and Biomass Blends-Current Trends.

In recent years, ecological issues have led to the search for new green materials from biomass as precursors for producing carbon materials (CNFs). Such green materials are more attractive than traditional petroleum-based materials, which are environmentally harmful and non-biodegradable. Biomass could be ideal precursors for nanofibers since they stem from renewable sources and are low-cost. Recently, many authors have focused intensively on nanofibers’ production from biomass using microwave-assisted pyrolysis, hydrothermal treatment, ultrasonication method, but only a few on electrospinning methods. Moreover, still few studies deal with the production of electrospun carbon nanofibers from biomass. This review focuses on the new developments and trends of electrospun carbon nanofibers from biomass and aims to fill this research gap. The review is focusing on recollecting the most recent investigations about the preparation of carbon nanofiber from biomass and biopolymers as precursors using electrospinning as the manufacturing method, and the most important applications, such as energy storage that include fuel cells, electrochemical batteries and supercapacitors, as well as wastewater treatment, CO2 capture, and medicine.

Higher heating value, exergy, pyrolysis kinetics and thermodynamic analysis of ultrasound-assisted deep eutectic solvent pretreated watermelon rind biomass

The higher heating value (HHV) and exergy of ultrasound-assisted deep eutectic solvent pretreated watermelon rind (WMR) biomass were investigated. Thereafter, the co-pyrolysis of the WMR biomass and coal blends was studied. The pyrolysis kinetics and thermodynamic parameters of the WMR-coal blends were determined using four isoconversional models (Flynn-Wall-Ozawa, Kissinger-Akahira-Sunose, Friedman and Starink). The HHVs of the pretreated WMR ranged between 12.73 and 19.28 MJ/kg, while the exergy value for the raw and pretreated WMR were 16.08 and 21.55 MJ/kg, respectively. The lower heating value related exergy had the greatest influence on the overall exergy of the WMR. The values of the pre-exponential factor showed variations in wide range, and the change in entropy of the system displayed both negative and positive entropies. The activation energy and enthalpy varied directly with the amount of coal in the blends. Amongst the isoconversional model methods, Friedman model was the best predictor of the kinetic parameters.

Torrefaction Characteristics of Blended Ratio of Sewage Sludge and Sugarcane Bagasse for Energy Production

Torrefaction is a thermal pretreatment technique usually adopted for improving biomass properties to be on par with that of coal for energy production. In this study, the torrefaction characteristics of blended fuel of sewage sludge (SS) and sugarcane bagasse (BG) biomass were investigated for the purpose of gasification. The thermal degradation behavior of the blended biomass sample was tested in an inert atmosphere from ambient temperature to 900 °C using thermogravimetric analysis (TGA). The obtained TGA data aided in the determination of thermochemical parameters that are of necessity in gasification. Morphological changes in the blended torrefied samples were examined through scanning electron microscopy. Further changes in the chemical structure of the samples were investigated through Fourier-transform infrared analysis. The blend ratio of 75% SS + 25% BG torrefied at 350 °C gave the highest energy value (HHV) of 23.62 MJ/kg, fixed carbon of 51.37 wt % and fuel ratio of 1.70. The obtained fuel ratio is comparable to that required for optimum combustion performance of coal. The morphological structure of the samples showed that there was an aggregation of the biomass particles into small lumps at higher torrefaction temperature for 50% SS + 50% BG and 75% SS + 25% BG blend indicating a better grind ability of the biomass material. Thus, it can be concluded that the blend and torrefaction enhanced the properties of the biomass materials.

Techno-Economic Analysis of decentralized preprocessing systems for fast pyrolysis biorefineries with blended feedstocks in the southeastern United States

This study evaluated the economic feasibility of fast pyrolysis biorefineries fed with blended pine residues and switchgrass in the Southeastern U.S. with different supply chain design. Previous techno-economic analyses (TEA) have focused on either blended biomass or decentralized preprocessing without investigating the impacts of varied process parameters, technology options, and real-world biomass distribution. This study fills the literature gap by modeling scenarios for different biomass blending ratios, biorefinery and preprocessing site (so-called depot) capacities, and alternative preprocessing technologies. High-resolution, real-world geospatial data were analyzed using Geographic Information Systems to facilitate supply chain design and TEA. For a decentralized system, the minimum fuel selling price (MFSP) of biofuel was $3.92–$4.33 per gallon gasoline equivalent (GGE), while the MFSP for the centralized biorefinery at the same capacities ranged between $3.75–$4.02/GGE. Implementing a high moisture pelleting process depot rather than a conventional pelleting process lowered the MFSP by $0.03–$0.17/GGE. Scenario analysis indicated decreased MFSP with increasing biorefinery capacities but not necessarily with increasing depot size. Medium-size depots (500 OMDT/day) achieved the lowest MFSP. This analysis identified the optimal blending ratios for two preprocessing technologies at varied depot sizes. Counterintuitively, increasing the proportion of higher cost switchgrass reduced the MFSP for large biorefineries (>5000 ODMT/day), but increased the MFSP for small biorefineries (1000–2500 ODMT/day). Although the decentralized systems have a higher MFSP based on current analysis, it has other potential benefits such as mitigated supply chain risks and improved feedstock quality that are difficult to be quantified in this TEA.

Co-gasification of high-density polyethylene and pretreated pine wood

Co-gasification of biomass and plastic blends has been extensively studied, however the effect of AAEMs (alkali and alkaline earth metals) in biomass on the co-gasification behavior still remains unknown. Acid and alkali pretreatment were used here to remove or introduce the AAEMs in biomass by ion-exchange method. SEM was used to obtain morphological characteristics of three pretreated pine wood (PW) samples; TG analysis of pure and blend feedstocks was used to examine the decomposition behavior. CO2 assisted co-gasification of high-density polyethylene (HDPE) and pretreated PW samples at different blend ratios were conducted in a fixed bed reactor, and the resulting flow rate and yields of H2, CO, light hydrocarbons (HC), total syngas, and output energy determined. Synergetic effects from these blends during co-gasification were evaluated by comparing the experimental results with the weighted results from individual components. Results showed that the presence of AAEMs in biomass resulted in increased char yield and char reactivity, that enhanced the syngas yield and energy output. However, acid pretreatment with low AAEM content showed the opposite trend. Irrespective of the biomass pretreatment, synergistic effect was found in the yield of each syngas component, total syngas, and energy yield during its co-gasification with HDPE plastic. The synergy during co-gasification of HDPE and alkali treated PW was more pronounced at high PW content, while those from acid pretreatment preferred low PW fraction. The highest energy yields of 28.1, 34.3 and 30.1 kJ/g were obtained from co-gasification of HDPE and water, acid and alkali pretreated PW samples at PW fraction of 44%, 22% and 55%, respectively. Maximum synergistic effect with energy yield of 69% was obtained from the gasification of HDPE and acid pretreated PW at 27% PW fraction. These results help to our understanding of the influence of biomass pretreatment on co-gasification of biomass-plastic mixtures. The results also help to achieve relatively stable energy output for varying mixtures of plastic and biomass.

A stochastic biomass blending problem in decentralized supply chains

AbstractBlending biomass materials of different physical or chemical properties provides an opportunity to adjust the quality of the feedstock to meet the specifications of the conversion platform. We propose a model which identifies the right mix of biomass to optimize the performance of the thermochemical conversion process at the minimum cost. This is a chance‐constraint programming (CCP) model which takes into account the stochastic nature of biomass quality. The proposed CCP model ensures that process requirements, which are impacted by physical and chemical properties of biomass, are met most of the time. We consider two problem settings, a centralized and a decentralized supply chain. We propose a mixed‐integer linear program to model the blending problem in the centralized setting and a bilevel program to model the blending problem in the decentralized setting. We use the sample average approximation method to approximate the chance constraints, and propose solution algorithms to solve this approximation. We develop a case study for South Carolina using data provided by the Billion Ton Study. Based on our results, the blends identified consist mainly of pine and softwood residues. The blends identified and the suppliers selected by both models are different. The cost of the centralized supply chain is 2%–6% lower. The implications of these results are twofold. First, these results could lead to improved collaborations in the supply chain. Second, these results provide an estimate of the approximation error from assuming centralized decision making in the supply chain.

Effects of Algal Biomass Blending on Coal Decomposition Behaviour and Kinetics at Intermediate Pyrolysis Regimes

Co-pyrolysis of coal with biomass is becoming a popular method of reducing the net carbon dioxide emissions associated with the process. In present work, the pyrolysis of coal and algae was studied using thermogravimetric methods and the kinetics were analyzed using the Coats-Redfern integral method. The kinetics were evaluated for 1st and 2nd order reaction models. The effect brought by blending coal with algae on kinetics was studied via the analysis of pyrolysis of different coal-algae blends. The results revealed that the pyrolysis of coal and algae follows 2nd and 1st order kinetics with activation energy evaluated in the range 213.4-241.8 and 108.9-122.8 kJ/mol, respectively. It was observed that for coal-algae blending of 20-40% algae, intermediate pyrolysis, typical heating rates of 50-200 ºC/min was characterized by two distinct stages (ignoring the drying stage) that correspond to the individual decomposition of algae and coal. However, there was an evidence of coal-algae interactions during co-pyrolysis, which made the kinetics of the two distinct stages not to correspond to the kinetics of the individual materials.

The Impact of Coal and Biomass Co-Firing on the Economy of Power Plant Carbon Capture

A detailed economic evaluation was carried out to determine the impact of biomass and coal co-firing on power plant carbon capture by methods of plants equipment designing factors and performance, and the sum up of the associated breakdowns of CAPEX and OPEX. Based on the assumptions of the CO2 neutrality of biomass and likely governmental incentives to reduce CO2 emissions, the study results show that biomass and coal co-firing would result in both lower cost of carbon avoided (carbon capture) and lower incremental cost of electricity generation when MEA solvent carbon capture is applied. Two scenarios for co-firing with carbon capture, 30% biomass blending and 90% or 60% CO2 capture from stack, indicate different preference depending on lower or higher incentives.

Thermochemical conversion of coal and biomass blends in a top-lit updraft fixed bed reactor: Experimental assessment of the ignition front propagation velocity

Co-thermochemical conversion of coal and biomass can potentially decrease the use of fossil carbon and pollutant emissions. This work presents experimental results for the so-called top-lit updraft fixed bed reactor, in which the ignition front starts at the top and propagates downward while the gas product flows upwards. The study focuses on the ignition front propagation velocity for the co-thermochemical conversion of palm kernel shell and high-volatile bituminous coal. Within the range of assessed air superficial velocities, the process occurred under gasification and near stoichiometric conditions. Under gasification conditions increasing coal particle size from 7.1 to 22 mm decreased ignition front velocity by around 26% regardless of the coal volume percentage. Furthermore, increasing coal volume percentage and decreasing coal particle size result in product gas with higher energy content. For the operation near stoichiometric conditions, increasing coal volume percentage from 10 to 30% negatively affected the ignition front velocity directly proportional to its particle size. Additional experiments confirmed a linear dependence of ignition front velocity on air superficial velocity. Further steps in the development of the top-lit updraft technology are implementing continuous solids feeding and variable cross-sectional area and optimizing coal particle size distribution.

Numerical study of preheating primary air on pinewood and corn straw co-combustion in a fixed bed using Eulerian-Eulerian approach

The effect of preheating primary air on the co-combustion characteristics of a 50–50% blend of pinewood and corn straw in a fixed bed. The primary air temperatures were assessed from 20 to 130 °C. The co-combustion characteristics were included the co-combustion behaviors and emissions. In order to reveal the features of the combustion process in the porous bed, a two-dimensional unsteady state model was employed to investigate the combustion process in a fixed bed of blended biomass on the combustion process in a fixed bed reactor. Conservation equations of the bed were implemented to describe the combustion process. The gas phase turbulence was modeled using the k-ε turbulent model and the particle phase was modeled using the kinetic theory of granular flow. Results showed that by increasing primary air temperature the residual mass on bed decreased, while the average burning rates and ignition front propagation velocity increased At the primary air temperature of 85 °C the smallest unburned carbon was left in the ash, and the emissions of nitrogen-compounds were relatively small. In contrast, the primary air temperature of 85 °C was found to be well-operating condition, which can be suggested for industrial boiler during blend co-combustion. The simulation results were then compared with experimental data for different temperature, which shows that the combustion process in the fixed bed is reasonably simulated. The simulation results of solid temperature, gas species and process rate in the bed are accordant with experimental data.

Modeling and parametric optimization of air catalytic co-gasification of wood-oil palm fronds blend for clean syngas (H2+CO) production

Syngas production from biomass gasification is a potentially sustainable and alternative means of conventional fuels. The current challenges for biomass gasification process are biomass storage and tar contamination in syngas. Co-gasification of two biomass and use of mineral catalysts as tar reformer in downdraft gasifier is addressed the issues. The optimized and parametric study of key parameters such as temperature, biomass blending ratio, and catalyst loading were made using Response Surface Methodology (RSM) and Artificial Neural Network (ANN) on tar reduction and syngas. The maximum H2 was produced when Portland cement used as catalyst at optimum conditions, temperature of 900 °C, catalyst-loading of 30%, and biomass blending-ratio of W52:OPF48. Higher CO was yielded from dolomite catalyst and lowest tar content obtained from limestone catalyst. Both RSM and ANN are satisfactory to validate and predict the response for each type of catalytic co-gasification of two biomass for clean syngas production.