Coal-biomass Blends Research Articles

Power generation with negative CO2 emissions through bio-electricity with CCS using dry co-gasification of coal-biomass blends

Power generation with negative CO2 emissions through bio-electricity with CCS using dry co-gasification of coal-biomass blends

Experimental Combustion of Different Biomass Wastes, Coals and Two Fuel Mixtures on a Fire Bench

When designing settlements according to the “Green Building” principle, it is necessary to develop a heating system based on climatic conditions. For example, in areas with a sharply continental climate (cold and prolonged winters), it is sometimes necessary to use solid fuel boilers (in the absence of gas). However, to use these, it is necessary to use biomass or biomass-coal blends as fuel to increase their combustion heat. The addition of biomass waste to coal can be aimed at achieving various objectives: utilization of biomass waste; reduction of solid fossil fuel consumption; improvement of environmental performance at coal-fired boiler houses; improvement of the reactivity of coals or to improve the technical and economic performance of heat-generating plants due to the fact that biomass is a waste from various types of production, and its cost depends only on the distance of its transportation to the boiler house. In this work, combustion of various biomass wastes, including sewage sludge, was carried out on a fire bench emulating the operation of a boiler furnace. Fuel particles were ignited by convective heat transfer in a stream of hot air at a velocity of 5 m/s in the temperature range of 500–800 °C, and the experimental process was recorded on a high-speed, color video camera. The obtained values were compared with the characteristics of different coals used in thermal power generation (lignite and bituminous coal). The aim of the work is to determine the reactivity of various types of biomass, including fuel mixtures based on coal and food waste. The work presents the results of technical and elemental analysis of the researched fuels. Scanning electron microscopy was used to analyze the fuel particle surfaces for the presence of pores, cracks and channels. It was found that the lowest ignition delay is characteristic of cedar needles and hydrolyzed lignin; it is four times less than that of lignite coal and nine times less than that of bituminous coal. The addition of hydrolysis lignin to coal improves its combustion characteristics, while the addition of brewer’s spent grain, on the contrary, reduces it, increasing the ignition time delay due to the high moisture content of the fuel particles.

Investigations on co-gasification and combustion characteristics of coal biomass blend as an alternative transport fuel for tri-cycles

Investigations on co-gasification and combustion characteristics of coal biomass blend as an alternative transport fuel for tri-cycles

Characterization of fuel composite obtained by the mixing of biomass and coal

ABSTRACT This research investigates the potential of biomass-coal blends as an alternative fuel source, focusing on coal from Darra Adam Khel, Cherat, Harnoi, and Daola in the KPK province of Pakistan and Parthenium weed biomass. The study assesses the impact of varying biomass ratios on proximate analysis (net calorific value (NCV), sulfur content, volatile matter, ash content, and moisture content) and calorific values of the composite fuel. Results reveal a linear NCV decline with increasing biomass, affecting high NCV coals less. Daola and Darra coal, starting at 30.43 and 31.32 MJ/kg, decreased to 20.15 MJ/kg and 19.71 MJ/kg with 66% biomass. Sulfur content, notably high in high NCV coals, significantly reduces with biomass; Darra coal decreases from 3.31% to below 1% with 66% biomass. Volatile matter uniformly increases with incremental biomass, enhancing combustibility. Cherat coal, initially at 8% volatile matter, rises to 50% with 66% biomass. Biomass effectively reduces ash content, particularly beneficial for low NCV coals. Harnoi coal, starting with 73% ash content, decreases to 30% with 66% biomass. However, biomass addition raises moisture content due to challenges in removing moisture from Parthenium weed. In summary, these findings optimize biomass-coal blends for enhanced fuel performance, address environmental concerns, and improve combustion efficiency, highlighting their potential as sustainable and eco-friendly energy sources.

Synergistic reduction of SO2 emissions while co-firing biomass with coal in pilot-scale (1.5 MWth) and full-scale (471 MWe) combustors

The objective of this study was to understand the synergistic effect of sulfur dioxide (SO2) emission reduction during the combustion of biomass-coal blends in comparison to pure coal by recording the gaseous SO2 concentrations, analyzing the composition of combustion ash by energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD), and simulating and verifying the fate of sulfur by a thermodynamic equilibrium software (FactSage). In Set A experiments, five combinations of coal and steam-exploded biomass (100/0, 75/25, 50/50, 25/75, 0/100 in percentages by mass) were co-fired in a 1.5 MWth pilot-scale combustor. In Set B, pure coal (100/0) and an 85/15 percent mass blend of coal and torrefied biomass were co-fired in a 471 MWe utility boiler. Woody biomass contains lower amounts of sulfur compared to coal and the linear lowering of SO2 emissions as a result of co-firing is called the dilution effect. For Set A tests, FactSage predicted, and ash analysis confirmed that calcium was primarily responsible for the synergistic emission reduction (beyond dilution effect) in all the blends, except in pure biomass, where potassium was responsible. During pure coal combustion, 41.1% of the sulfur in the system was absorbed in the ash, compared to 97.0% during pure biomass testing. In Set B tests, the 85/15 coal-biomass blend, showed a 28.1% reduction in SO2 emissions along with a 22.1% reduction in the lime slurry utilization at flue gas desulfurization (FGD) towers compared to pure coal, which is equivalent to saving 7.4 L of lime slurry per MWe-hour. The results suggest that blending woody biomass with coal can help coal-fired utility boilers meet environmental emission standards and reduce desulfurization costs. These results are important since the current literature is deficient in research conducted at suspension-fired full-scale boilers to reduce SO2 emissions by co-firing coal and biomass blends.

Study of Ash Sintering Temperature and Ash Deposition Behavior during Co-Firing of Polish Bituminous Coal with Barley Straw Using Non-Standard Tests

The need to reduce CO2 emissions forces the use of biomass as a fuel in the conventional energy conversion process implemented by combustion. Burning biomass alone can be problematic because of the high potential for slugging and fouling on boiler heating surfaces. Therefore, co-firing of biomass with coal is used. This article presents the results of a study of biomass blends of barley, straw, and hard coal biomass from the Polish Makoszowy mine. The sintering of ash from biomass-coal blends was studied by experimental non-standard methods, such as the fracture stress and the pressure drop test. The results were confirmed with the result of thermodynamic modeling using FactSage 8.0 software. Additionally, ash deposition tests were performed in a 3.5 m boiler. The tests conducted showed a significant effect of the addition of biomass to hard coal on the formation of ash deposits on the heating surfaces of the boiler. In addition, the usefulness of non-standard methods in the assessment of the degree of fouling and slugging hazard was confirmed.

Comparison of synchronous generators for autonomous gasoline installation system

There are many power plants like thermal, solar, hydro, nuclear etc. but there are some disadvantage of it like CO2 emission pollution, problem of global warming requirement of fuels cost etc. To avoid such factors we developed system is biomass power plant to meet the demands of electricity and environment concern day by day price of fuels that fact to which motivate to use renewable energy. Biomass is renewable in nature, carbon neutral and has the potential to provide large productive employment in rural areas. It is considered as one of the promising sources for generation of power / energy using commercially available thermal and biological conversion technologies. The fossil fuels are depleting very fast, it is very important to replace fossil fuels with best alternative fuel modes which will be available for requirement in abundance at the same time if it is ready at one’s disposal is a eminent balance to the environment. The sanctification for this need is the bio mass power plant; on finding the major advantage of bio mass power plant is the fuel which is agricultural waste (rice husk, wood, etc.) segregation available in unnumbered tons around the world. It is very important to utilize this in the context of energy. It is also found that the sulphur content in the biomass is very less when compared with coal. The wood fuels contains very little ash (-1% or less), so increasing the ratio of wood in biomass coal blends can reduce the amount of ash that must be disposed. In biomass power plants, wood waste or other waste is burned to produce steam that runs a turbine to make electricity, or that provides heat to industries and homes. Fortunately, new technologies including pollution controls and combustion engineering have advanced to the point that any emissions from burning biomass in industrial facilities are generally less than emissions produced when using fossil fuels (coal, natural gas, oil), biomass is burned in a combustor or furnace to generate hot gas, which is fed into a boiler to generate steam, which is expanded through a steam turbine or steam engine to produce mechanical or electrical energy. In this paper were performed comparison of traditional synchronous generator with electromagnetic excitation and permanent magnet generator for autonomous gasoline installation system.

In depth thermokinetic investigation on Co-pyrolysis of low-rank coal and algae consortium blends over CeO2 loaded hydrotalcite (MgNiAl) catalyst

This study investigates the co-pyrolysis behavior of bituminous coal (100%BC), algae consortium (100%AC), and their blends at various blending ratios. The pure and coal-biomass blends were characterized using CHN-S, GCV, and FTIR analysis. Whereas, the co-pyrolysis of blends were performed in a TGA. The deviation between the experimental and calculated values of weight loss (WL%), the residue left (RL%), and the maximum rate of weight loss (wt%/min) was used to calculate the synergistic effects. Kinetic parameters were investigated using the Coats-Redfern integral method through eighteen (18) reaction mechanistic models. The activation energy (Ea) for 100%BC was 85.04 kJ/mol through the F3 model, whilst for 100%AC showed 78.22 kJ/mol using the D3 model. Thermodynamic parameters such as Enthalpy (∆H) and Gibbs free energy (∆G) showed positive values, while Entropy (∆S) was negative for each coal-biomass blend. The catalytic co-pyrolysis of the optimum blend (20BCE-80AC) was studied using CeO2 loaded MgNiAl (CeO2 @MNA) as a multifunctional catalyst. The increased WL% displayed a positive effect toward a higher yield of volatile matter. Ea of the optimum blend in co-pyrolysis was further reduced through catalytic co-pyrolysis and Ea in the first and second stages was 72.48 kJ/mol and 13.76 kJ/mol, while 3 wt% catalyst loading further reduced its Ea in both stages to 67.82 kJ/mol and 41.21 kJ/mol. The use of CeO2 @MNA at 3 wt% loading showed a reduction in the peak devolatilization temperature (Tp) of the optimum blend substantially increasing the reaction rate, and reducing the Ea required for the decomposition process.

Investigating the characterisation, kinetic mechanism, and thermodynamic behaviour of coal-biomass blends in co-pyrolysis process

The integration of biomass into existing thermochemical conversion processes for bioenergy production is expected to play a key role in the energy transition to reduce the reliance on depleting fossil fuels and mitigate fossil carbon emissions. In this study coal-biomass blends containing hemp and sawdust were prepared with various blending ratios for co-pyrolysis. The coal-biomass blends were characterised using ultimate analysis (CHN), gross calorific value (GCV), FTIR, and TGA. Co-pyrolysis was performed in TGA that was applied to study the thermokinetic behaviour of the respective blends. The deviation between the experimental and calculated values of TGA mass loss (ML), the residue left (RL), and maximum mass loss rate (DTGmax) were calculated to observe the synergistic effect. The positive deviation in the ML and DTGmax values indicated the presence of a synergistic effect during co-pyrolysis. Kinetic parameters were analysed by employing the Coats-Redfern method with thirteen integral functions. The activation energy (Ea) for individual coal was 39 kJ/mol through a one and a half chemical reaction (F3/2), while individual sawdust and hemp showed 60 kJ/mol through a deceleratory reaction mechanism for contracting sphere (R3) and 44 kJ/mol through the second-order chemical reaction (F2), respectively. Thermodynamic parameters such as the change in enthalpy (ΔH) and change in Gibbs free energy (ΔG) showed positive values that indicate the reaction was non-spontaneous. Additionally, the change in entropy (ΔS) was negative that suggested a more ordered state. The coal-sawdust blends were found to be suitable for the production of bio-oil as the individual sawdust contained a higher number of volatiles, whereas the coal-hemp blends were better suited for the production of biochar since the individual hemp produced more residue after co-pyrolysis. Hemp biochar was further characterised by FTIR, TGA, GCV, and SEM-EDX analysis to investigate its potential in environmental and energy applications.

A Comparison of Combustion Properties in Biomass-Coal Blends Using Characteristic and Kinetic Analyses.

This paper presents comparative research on the combustion of coal, wheat, corn straw (CS), beet residues after extracting sugar (BR), and their blends, coal–corn straw blends (CCSBs), coal–wheat blends (CWBs), and coal–beet residue blends (CBRBs), using thermogravimetric (TG) analysis under 10, 20, 30, 40 and 50 °C/min. The test results indicate that CS and wheat show better combustion properties than BR, which are recommended to be used in biomass combustion. Under the heating rate of 20 °C/min, the coal has the longest thermal reaction time when compared with 10 and 30 °C/min. Adding coal to the biomass can improve the burnout level of biomass materials (BM), reduce the burning speed, and make the reaction more thorough. The authors employed the Flynn–Wall–Ozawa (FWO) method and the Kissinger–Akahira–Sunose (KAS) method to calculate kinetics parameters. It was proven that overall, the FWO method is better than the KAS method for coal, BM, and coal–biomass blends (CBBs), as it provides higher correlations in this study. It is shown that adding coal to wheat and BR decreases the activation energy and makes conversion more stable under particular α. The authors selected a wider range of biomass raw materials, made more kinds of CBB, and conducted more studies on different heating rates. This research can provide useful insights into how to choose agricultural residuals and how to use them.

Evaluation of the effect of high sulfur subbituminous coal on the devolatilization of biomass residue by using model free, model fitting and combined kinetic methods

In order to sustainably utilize waste biomass and low-grade coal for energy generation, a comprehensive thermo-kinetic investigation was done to understand the effect of addition of a high sulfur subbituminous coal on the devolatilization behaviour of a biomass residue. At first, kinetics, mechanisms and thermodynamic parameters were evaluated by model-free and model-fitting methods. Combine kinetic model (CK-model) was then used to corroborate the results obtained from these methods. Results reveal that the addition of coal improves biomass devolatilization behaviour and best performance is observed when 50% biomass is replaced by coal. Mean activation energies (Eo) and Arrhenius constants (Ao) of biomass determined by KAS/DAE method are 197.6 kJ.mol−1 and 5.5 × 1014 s−1, respectively. Similarly, Eo and Ao values are respectively 161.7 kJ mol−1 and 3.01 × 106 s−1 for 50% coal containing blend and 169.0 kJ mol−1 and 2.0 × 107 s−1 for 75% blend. A positive synergistic effect of coal addition on biomass pyrolysis is observed from the kinetic behaviour, which is also dependent on the biomass to coal ratios. Pyrolysis of biomass with or without coal initially follow order-based model which gradually changes to diffusion model at later stage of conversion. Single-step CK-model based pyrolysis mechanisms of plain, 50 and 75% coal blended biomass are f(α) = (1 − α)1.109.α−2.9037.[−ln(1 − α)]1.1035, f(α) = (1 − α)1.0725.α−2.4681.[−ln(1-α)]0.9967, and f(α) = (1 − α)1.1256.α−2.9990.[−ln(1 − α)]1.2453, respectively. Activation energies and reaction orders predicted by CK-model are similar to the values predicted by isoconversional- and CR-methods, respectively. Results also show that the kinetic parameters obtained from CK-model satisfactorily explains the devolatilization kinetics of biomass-coal blends. Therefore, the results obtained from this comprehensive investigation are helpful in the designing of pyrolysis reactor systems for co-conversion of biomass-coal mixture to liquid and gaseous products.

Co-Combustion Characteristics of Typical Biomass and Coal Blends by Thermogravimetric Analysis

In this study, the co-combustion characteristics of coal and biomass blends (20, 40, 60, 80, and 100 wt%) were investigated by thermogravimetric analysis. All the samples were operated under an oxidative atmosphere, with a heating rate of 20 C/min. The reaction stages, ignition and burnout temperature, maximum weight loss rate, and different combustion indices were determined. When the percentage of biomass in the blends was increased, the maximum mass loss rate was enhanced in the second region, and the ignition and burnout temperature was lowered, indicating the higher reactivity and better combustion performance of the samples. The comprehensive performance index presented an N shape with the increasing biomass blending ratio. Based on various combustion indices, 20% was an optimum percentage for the co-utilization of coal-biomass blends. A significant promoting interaction was observed between corn straw and rice straw blends, while inhibiting effects occurred between rice husk and coal. The kinetic parameters of the blends were evaluated by the Coats and Redfern method using the nth-order reaction model. The value of activation energy and the pre-exponential factor increased with the decreasing biomass percentage in the blends.

Study on chemical characteristics of coal and biomass blend and the tendency of its ash deposition

A coal and biomasses of empty fruit bunch (EFB), mesocarp fiber (MF) and palm kernel shell (PKS) were characterized in terms of its proximate, ultimate, calorific value and ash chemical composition. Ash fusion temperature (AFT) was carried out on coal and biomass blends with a composition in weight % of 95-5; 90-10 and 85-15. The coal used in this research has high calorific value of 6,106 cal/g. Results indicate that based on the AFT, the coal-biomass blends at some composition shows a medium tendency to ash deposition. While based on the chemical composition, generally the coal-biomass blends have a low tendency to slagging but have a high tendency to fouling. Coal-biomass blend at the coal composition of 85 wt% and PKS of 15 wt% (85-15) is recommended to be applied. The less the coal is used, the less the CO2 emission, so it is expected to reduce the GHG significantly.

Life cycle meta-analysis of carbon capture pathways in power plants: Implications for bioenergy with carbon capture and storage

Bioenergy with carbon capture and storage (BECCS) based electricity generation is one possible approach for delivering large-scale carbon dioxide removal from the atmosphere. This study evaluates the environmental impacts of leveraging existing power plants for BECCS. We performed a life cycle meta-analysis of eight carbon capture technologies, including five previously simulated only for coal and natural gas, for both steam cycle and integrated gasification combined cycle (IGCC) power plants. We found that IGCC plants offer the best balance of negative emissions, energy return on investment (EROI) and low water use irrespective of capture technologies. Planned IGCC plants tend to be large whereas biomass-fired power plants are often small and distributed in the landscape because of the distributed nature of the fuel. Steam cycle plants had larger negative emissions, but also lower EROI, and so blending with coal may be necessary to achieve a suitable EROI. Steam cycles were sensitive to capture technology type, and results found membrane and calcium looping capture technologies offer a balance between negative emissions, EROI and water use when fired using coal-biomass blends. These results suggest that steam cycle power plants may be the most desirable candidates to support early-stage deployment of BECCS.

Influence of biomass thermal pre-treatment on the particulate matter formation during pulverized co-combustion with lignite coal

This work investigated the particulate matter formation during co-combustion of thermally pre-treated biomass with coal. Olive residue was chosen as agricultural waste biomass, and Tunçbilek lignite as the coal. The biomass was thermally pretreated to assess the influence of the pretreatment temperature on particulate matter formation during co-combustion. Specifically, the olive residue was torrefied (at 275 °C) and pyrolyzed (at 500 °C) using a tubular oven. The biomass-coal blends in a 50:50 wt% ratio were co-fired in a drop tube furnace operated at 1200 °C, heating rate of ∼ 104 °C/s, residence time of ∼ 3 s, and dry air atmospheric conditions. The particulate matter was collected at the bottom of the reactor using a three-stage stack impactor which allowed to quantify the relevant levels of PM2.5, PM2.5-10, and PM10. The results showed that co-combustion resulted in clear reduction of PM2.5 emission to values close to those of the biomass fuel. Specifically, combustion of blends of Tunçbilek lignite with olive residue, torrefied olive residue, and olive residue char resulted in 646, 408, and 559 mg/MJ input, respectively. Moreover, the mechanisms responsible for the formation of PM2.5 during biomass and coal combustion were found applicable to biomass-coal blends. The shift from fine to coarser particles with co-firing is likely to allow the capture of PM from biomass-coal co-firing by conventional coal-PM traps in existing coal power plants.

Thermochemical Conversion of Coal and Coal-Biomass Blends in an Autothermal Moving Bed Gasifier: Experimental Investigation

A unique laboratory scale auto-thermal moving bed gasifier was designed for studying the thermochemical conversion of coal-biomass blends. For this purpose, two coals (lignite and sub-bituminous), two biomass materials (corn stover and switchgrass), and their respective blends were used. Gasification characteristics of the fuels were evaluated with an emphasis on improving the producer gas composition. The efficiency and product gas compositions reveal that utilizing the inner stainless-steel tubing better promotes heat transfer upwards in the axial direction when compared to utilizing quartz insulation. The H2/CO ratio at the same operating conditions is much higher due to the increase in bed temperature and heat transfer upwards in the axial direction. This improved the overall efficiency by at least 20%. Using pure oxygen and steam, efficiency greater than 50% was obtained for blends with corn stover at steam to oxygen ratio of 2:1. Also, using air as the gasifying agent greatly improved the H2/CO ratios and overall efficiency in blends with corn stover. In contrast, blends with switchgrass were not very effective with respect to the overall gasification characteristics. Blending switchgrass with coal may not be viable option from the viewpoint of generating high quality producer gas for downstream operations.

Dataset from estimation of gasification system efficiency using artificial neural network technique

Abstract The dataset contained in this article supplements the data information contained in the performance evaluation of gasification system efficiency using artificial neural network technique. The dataset was obtained from investigating efficiency of a gasification system using 315 fuel samples containing biomass, coal, and coal-biomass blends via the application of Levenberg–Marquardt (LM) back-propagation and Bayesian Regularization (BR) training algorithms in Artificial Neural Networks (ANN) domain. Input Variables Representation Technique-by-Visual Inspection method (IVRT-VIM) and Output Variables Representation Technique –by-Visual Inspection Method (OVRT-VIM) were developed as well to improve results from the ANN models. Sensitivity analysis on the prediction of the product gas compositions (CO, CO2, H2, and CH4) was carried out using partial derivatives (PaD) method. There was a considerable decrease in the MSE and an increase in the R2 of around 93 – 96% and 94 – 96% using 10 & 23 number of neurons in the hidden layer and IVRT-VIM technique, respectively. The L -M algorithm offered a better result than the BR algorithm, and with Sulphur as the most important input variable that affected the outputs.

Co-gasification of high ash Indian coal-biomass blends in a pilot-scale fluidized bed gasifier

Conventional coal-based technologies are experiencing several disadvantages due to its high ash content as well as a significant amount of greenhouse gas emission. Focus is shifting towards the utilization of renewable resources like biomass. The efficient use of coal and biomass in a clean manner has been the driving force in developing gasification technologies. In the present investigation, an effort has been made to study the gasification performance of selected coal with two types of biomass, namely rice husk and sawdust in different proportions in a pilot-scale bubbling fluidized bed gasifier. Gasification was conducted with a mixture of air and steam at a temperature between 900–950 °C and atmospheric pressure. Mainly, three blends were prepared by adding 10, 20, and 40% of biomass with the selected coal. It was found that up to 40% of biomass loading, gasifier is operated in a trouble-free manner without the formation of tar or any agglomerate by maintaining proper fluidization with smooth and controlled variation in the process parameters like temperature, airflow, and steam flow rate. Due to the synergistic influence between coal and biomass, overall carbon conversion, gas yield, and gas heat value were found to increase with increasing biomass loading.

Ash Formation and Deposition in Oxy-fuel Combustion of Rice Husk, Coal, and Their Blend with 70% Inlet O2

Managing the risk of ash deposition is still a priority for oxy-fuel combustion of biomass–coal blends. This is especially a concern when high inlet O2 concentrations are adopted to reduce the amou...

Gasification of coal, Chenopodium Album biomass, and co-gasification of a coal-biomass mixture by thermogravimetric-gas analysis

Gasification studies were performed on sub-bituminous coal of the province Centro in Boyacá state of Colombia, vegetable biomass Chenopodium album (cenizo) and co-gasification of coal-biomass mixtures agglomerated with paraffin in a thermogravimetric analyzer. Biomass synergistically promoted thermochemical transformation of the coal was observed. Experimental results were compared to equilibrium composition simulations. Ash fusibility tests of the coal-biomass mixture were carried out, which allowed to clarify its behavior, such as dry or fluid ash according to own chemical composition, during the gasification process. The experimental tests allowed determining the differences in thermal decomposition, between coal, cenizo and coal-biomass blend, which are attributable to the physicochemical properties of each one solid fuel. During the tests, gas chromatography analyses were performed to establish the compositions of the syngas. The syngas obtained from biomass had the highest concentration of CO and the lowest H2; the coal and the coal-biomass mixture were slightly minor respectively. Concentrations of CH4, CO2 and C2H4 were similar between coal and biomass. This result is consistent with the higher calorific value of the coal syngas. The production of syngas from the coal-biomass mixture had the lowest contents of H2 and CO due to synergistic phenomena that occur with the fuel mixture. The co-gasification of the mixture gave the highest syngas production, carbon conversion, and thermal efficiency. These results indicate the viability of co-gasification of coal-Chenopodium album agglomerated mixtures. In gasification of non-agglomerated mixtures of coal-cenizo, the biomass can be burned directly without producing syngas.