Lower Heating Value Research Articles

Numerical and Experimental Investigation on Combustion Characteristics and Pollutant Emissions of Pulverized Coal and Biomass Co-Firing in a 500 kW Burner

The global shift towards clean energy has been driven by the need to address global warming, which is exacerbated by economic expansion and rising energy demands. Traditional fossil fuels, particularly coal, emit more pollutants than other fuels. Recent studies have shown significant efforts in using biomass as a replacement or co-firing it with coal. This is because biomass, being a solid fuel, has a combustion mechanism similar to that of coal. This study investigates the co-firing behavior of pulverized coal and biomass in a semi-combustion furnace with a 500 kW heat input, comprising a pre-chamber and a main combustion chamber. Using computational fluid dynamics (CFD) simulations with ANSYS Fluent 2020 R1, the study employs species transport models to predict combustion reactions and discrete phase models (DPM) to track fuel particle movement. These models are validated against experimental data to ensure accurate predictions of mixed fuel combustion. The research examines various biomass-to-coal ratios (0%, 25%, 50%, 75%, and 100%) to understand their impact on combustion temperature and emissions. Results show that increasing the biomass ratio reduces combustion temperature due to biomass’s lower heating value, higher moisture content, and larger particle size, leading to less efficient combustion and higher CO emissions. However, this temperature reduction also correlates with lower NOx emissions. Additionally, biomass’s lower nitrogen and sulfur content contributes to further reductions in NOx and SO2 emissions. Despite biomass having higher volatile matter content, which results in quicker combustion, coal demonstrates a higher carbon burnout rate, indicating more efficient carbon combustion. The study concludes that while pure coal combustion efficiency is higher at 87.7%, pure biomass achieves only 77.3% efficiency. Nonetheless, increasing biomass proportions positively impacts emissions, reducing harmful NOx and SO2 levels.

α-Al2O3 Functionalized with Lithium Ions Especially Useful as Inert Catalyst Bed Supports

The alumina, in the form of α-Al2O3 tabular balls, considered in this study is a high-purity form of aluminum oxide that has been fired at high temperatures (well above 1900 °C), virtually removing porosity. However, the purity and inertness of the surface of the Al2O3 tabular balls minimize the catalytic activity, which is why lithium doping was tried. Thus, the target of this study was the effect of doping with lithium ions in some tabular balls of Al2O3 (the crystalline structure is corundum) on the improvement of the catalytic properties of alumina. This study examined the impact of a lithium catalyst on the combustion of various fuels within a porous inert medium (PIM) burner. This study specifically compared low calorific gaseous fuel (e.g., biogas) combustion in a PIM burner with and without the lithium catalyst. The experimental setup comprised a gas preparation unit for mixing CNG and CO2 to simulate biogas and a PIM burner. The PIM burner comprised Al2O3 spheres (13 mm diameter, 45% porosity) in a random packing configuration. Three fuels, varying in composition and lower heating value (LHV ranging from 20.771 to 27.695 MJ/m3), were combusted at air ratios ranging from 1.67 to 1.79. The results indicated that the catalyst increased peak combustion temperatures by 23.2 °C to 51.4 °C, depending on the fuel type and air ratio. Significantly higher carbon monoxide (CO) concentrations were observed without the catalyst, particularly with fuel type F1, while nitrous oxide (NOx) levels remained consistently low. Upstream flame propagation was observed in the presence of the catalyst. These findings demonstrate the potential of lithium catalysts to enhance combustion stability and reduce emissions in porous media combustion burners. Following these studies, it can be stated that Li(I) has the role of promoter of the catalytic process.

Enhanced water removal from low-rank coal via flash evaporation: Insights into dewatering performance, upgrading effects, and energy analysis

ABSTRACT Low-rank coal has vast reserves and is widely used in power plants. Nevertheless, its high moisture content reduces coal’s heating value and power generation efficiency. This study explores an innovative steam flash-drying method, examining the impact of temperature, particle sizes, and heating duration on moisture removal. Investigations were conducted to assess the reabsorption behavior and changes in the heating value of the dried products, aiming to validate the method’s suitability for coal upgrading applications. Additionally, the energy consumption of the drying process was thoroughly analyzed. The results showed that the drying effect exhibited a positive correlation with the steam pressure/temperature, and the particle size was an important factor affecting the dewatering effect, among which the drying effect of the 13–0 mm particles was the best, with a dewatering ratio of 70%. The holding pressure time exhibits minimal influence on dehydration effectiveness. Steam flash drying removed 73.5% of free water and 23.5% of bound water. Moisture reabsorption was virtually nonexistent within 96 hours of storage. The lower heating value of the coal was increased from 19.9 MJ/kg to 23.65 MJ/kg by drying. The energy consumption of steam drying was 1711 kJ/kg H2O. The results of this study verified the feasibility of steam flash steaming for low-rank coal drying and provided technical support for the safe, efficient, and low-energy quality improvement of low-rank coal resources.

Influences of ternary ethanol methanol gasoline mixtures on the performance of a spark ignition engine

The principal aim of this study is to determine the influence of ternary mixtures of gasoline, ethanol and methanol as fuels, on a spark ignition engine performance. Four samples of fuels were prepared with varying concentrations of each constituent. The different fuels studied are: EM0 (gasoline), EM5 (2.5% ethanol, 2.5% methanol, 95% gasoline), EM10 (5% ethanol, 5% methanol, 90% gasoline) and EM15 (7.5% ethanol, 7.5% methanol, 85% gasoline). A battery of tests (appearance, color, odor, lower heating value, density, research octane number, vapor pressure, total sulfur content and distillation curve) was carried out on these mixtures in order to determine their physicochemical properties and their ability to be used as fuel. Then, the different prepared mixtures were used as fuels to determine the performance of the 4-stroke, carbureted Renault 4 engine. These tests show that these additions give rise to a fuel with a lower sulfur level, a higher RON and a lower low heating value compared to unleaded gasoline and therefore improve, depending on the circumstances, the power of the fuel engine, its specific consumption, its speed and combustion. At the end of this study, it was concluded that the use of fuel mixtures was relevant for high speeds and also more suitable for total loads.

Investigation on Syngas production from forest Biomass (Sapele, Sypo and Ayous) wood in the downdraft gasifier using Aspen plus and IC engine integration

This study aims to evaluate the potential for syngas production from three types of equatorial forestry biomass Sapele, Sipo, and Ayous using a downdraft gasifier. The main objective is to assess the energy potential of the produced syngas when used in an internal combustion engine with a 30% efficiency, coupled with a DC generator operating at 93% efficiency. The research focuses on determining the composition and energy output of syngas from these biomass types, as well as exploring the integration of downdraft gasification with internal combustion engines for localized energy production, particularly in decentralized power systems and microgrids. The research involved modeling and simulating the gasification process using Aspen Plus software. Proximate and ultimate analyses of the biomass samples were used to simulate gasification in a downdraft gasifier. The gasifier's performance was assessed through syngas composition analysis, focusing on energy output and overall system efficiency. The integration of downdraft gasification with an internal combustion engine was simulated to determine its feasibility in decentralized power systems and microgrids. The study revealed that all three biomass types produced syngas with high concentrations of carbon monoxide (CO) and hydrogen (H2), which are critical for energy generation. The lower heating value (LHV) of the syngas remained consistent among the samples, with Sapele at 13.51 MJ/Nm³, Sipo at 13.63 MJ/Nm³, and Ayous at 13.54 MJ/Nm³. Ayous achieved the highest gasification efficiency at 79.36%, followed by Sipo at 78.89% and Sapele at 76.05%. The simulation performed in Aspen Plus showed that Ayous produced the highest electric power output at 53.55 kW, followed by Sapele at 51.86 kW and Sipo at 49.18 kW. The results highlight the potential of equatorial forestry biomass, particularly Ayous, as a renewable energy source. All three biomass types can generate syngas of comparable quality in terms of energy content, with Ayous showing the highest efficiency. This research emphasizes the feasibility of using equatorial biomass for syngas production and its integration into internal combustion engines, supporting decentralized energy generation and reducing reliance on fossil fuels.

Utilization of Cocoa Pod Husk Waste as Fuel for Downdraft Type Gasification Reactor of 960 Liters Capacity in Berau Regency

This experiment aims to investigate the performance characteristics of a downdraft gasification reactor fueled by cocoa pod husk as a technological solution for obtaining alternative renewable energy sources to replace fossil fuels and natural gas. The research was conducted experimentally on a gasification reactor made of SS310 thermal resistant carbon steel material. The reactor has dimensions of 35 centimeter in diameter and 250 centimeter in height. Measurement of gasification zone using 7 units of K-type thermocouples that was installed along the reactor wall. Fuel was feeding continuously at a rate of 4kg/hour. The research was conducted by varying the temperature in oxidation zone, specifically at 900 ºC, 950 ºC, 1000 ºC, 1050 ºC, and 1100 ºC. Data collection was carried out in different temperature variations and processed to determine the performance parameters of the gasification reactor, including gas composition, temperature distribution on the reactor wall, and the lower heating value (LHV) of the syngas production. The results showed the highest temperature distribution of the reactor in the drying zone 205ºC, pyrolysis zone 575ºC and reduction zone 520 ºC that be obtained at the oxidation temperature of 1100 ºC . Meanwhile the optimum value of syngas quality was obtained at the oxidation temperature of 1000 ºC with the composition of flamable syngas CO, H2, and CH4 are 27.08%, 8.53% and 2.41% , with the highest LHV 5206 kJ/m3. In general the increasing of the oxidation temperature lead to a positive contribution to the performance of the gasification reactor using cocoa pod husk waste.

Distillation, Characterizations, and Testing of Distillation Products from Waste Lubricant Oil (WLO) using Compression-Ignition Engine

Waste lubricant oil is always found in motor vehicle repair shops. Utilizing waste lubricant oil by distilling it will provide benefits. For this reason, waste lubricant oil was distilled in this research. Several characterizations were conducted to determine the viscosity, density, low heat value (LHV), and flash point of waste lubricant oil and distillation products. The distillation product is less viscous, denser, LHV, and flash point than lubricant oil waste. The distillation product was mixed with Pertamina DEX (0, 5, 10, and 15 vol.%) and then filled into the fuel tank for the engine performance test. The present experiment utilized a compression-ignition (CI) engine to measure performance. CI engine speed variations were carried out at 1000, 1500, 2000, and 2500 to see the influence of the mixed fuel on torque, power, specific fuel consumption (SFC), thermal efficiency, and smoke opacity. The increase in CI engine speed leads to an increase in torque, power, thermal efficiency, and smoke opacity, but at the same time, SFC decreases to 2500 rpm. Increasing the distillation product content in the mixed fuel decreased torque, power, SFC, thermal efficiency, and increased smoke opacity.

Performance and Emission Characteristics of a Small Gas Turbine Engine Using Hexanol as a Biomass-Derived Fuel.

The global transition to renewable energy has amplified the need for sustainable aviation fuels. This study investigates hexanol, a biomass-derived alcohol, as an alternative fuel for small-scale gas turbines. Experimental trials were conducted on a JETPOL GTM-160 turbine, assessing blends of 25% (He25) and 50% (He50) hexanol with kerosene (JET A) under rotational velocities ranging from 40,000 to 110,000 RPM. The parameters measured included thrust-specific fuel consumption (TSFC), turbine inlet and outlet velocities, and the emission indices of NOx and CO. The results demonstrated that the He25 and He50 blends achieved comparable thermal efficiency to pure JET A at high rotational velocities, despite requiring higher fuel flows due to hexanol's lower heating value. CO emissions decreased significantly at higher velocities, reflecting improved combustion efficiency with hexanol blends, while NOx emissions exhibited a slight increase, attributed to the oxygen content of the fuel. This study contributes a novel analysis of hexanol-kerosene blends in gas turbines, offering insights into their operational and emission characteristics. These findings underscore hexanol's potential as an environmentally friendly alternative fuel, aligning with global efforts to reduce fossil fuel dependency and carbon emissions.

Towards an eco-social circular economy: exploring the feasibility study of pyrolysis on agricultural feedstocks

AbstractThe agricultural sector is challenging to decarbonise due to its reliance on heavy machinery and fossil fuels, which face issues when decarbonising via methods such as electrification. However, agriculture provides opportunities to generate renewable energy via biomass sources due to their abundance within this sector. This feasibility study used a continuous auger pyrolysis system to assess how straw waste from a medium-scale arable farm could convert energy from an external electrical source into usable chemical potential. Wheat, barley, oil seed rape (OSR), and bean straw have all been processed and pyrolysed under different temperatures and auger feed rates. The syngas product was then analysed, considering its composition and the lower heating value. Results indicate that the percentage of carbon monoxide and hydrogen and the total volume of syngas increased with temperature. In addition, the syngas’ energy quantity increased despite the product’s decreasing heating value. The case study’s annual energy demand was equal to 14.4% of the 3900 GJ maximum potential contained within the syngas, and thus it can be concluded that there is potential for the application of this system towards a circular economy. The system’s cold gas, net, and electrical conversion efficiency were also assessed with maximum values of 37.1%, 30.1%, and 174.4%, respectively. Furthermore, the statistical analysis confirms high predictability for wheat, barley, bean, and OSR feedstocks, with a general linear model showing high accuracy across all.

Evaluation and Analysis of the Energy Potential of Grapevine Peduncles of PIWI Group Varieties

This paper presents an analysis of the energy potential of grape stalk biomass from PIWI varieties, namely ‘Seyval Blanc’, ‘Muscaris’, ‘Hibernal’, and ‘Regent’, during the combustion process. Biometric, technical, and elemental analyses of the grape stalk biomass were conducted. We evaluated the mass, length, and width of the stalks and their contribution to the total cluster mass. The higher and lower heating values, moisture content, volatile compounds, ash, fixed carbon content, and elemental composition were analysed. Emissions of carbon monoxide, nitrogen oxides, carbon dioxide, sulphur, and particulates were also measured. A significant influence of the cultivar on the assessed biometric and technical parameters was found. ‘Muscaris’ exhibited the highest calorific value (HHV 16.44 MJ·kg−1) and the lowest ash content (9.99%). The highest carbon content (45.51%) was recorded for ‘Seyval Blanc’, and the highest hydrogen content (6.74%) for ‘Muscaris’. Nitrogen oxide emissions were the lowest for ‘Seyval Blanc’, making it more environmentally friendly. The biomass of grape stalks from PIWI varieties, particularly ‘Muscaris’ and ‘Seyval Blanc’, shows high energy potential and can be effectively utilised as a renewable energy source. Our results could be summarised as ‘sustainable energy production and reduced greenhouse gas emissions from grape stalks’.

Strategic optimization of engine performance and emissions with bio-hydrogenated diesel and biodiesel: A RVEA-GRNNs framework

This study investigates the effects of blending bio-hydrogenated diesel and biodiesel on engine performance and emissions across various engine speeds (2000-3000 rpm) and loads (25-90%), addressing the growing demand for sustainable transportation fuels. Using a single-cylinder diesel engine from POLAWAT ENGINE Company Limited, we evaluated different bio-hydrogenated diesel and biodiesel blends, optimizing their composition through the Reference Vector Guided Evolutionary Algorithm with a surrogate objective function via Generalized Regression Neural Networks. Results indicate that engine performance is closely linked to combustion temperature, which significantly affects fuel consumption and thermal efficiency. Bio-hydrogenated diesel demonstrated superior performance compared to conventional diesel, with lower fuel consumption and higher thermal efficiency, attributed to its higher cetane index (78 vs. 56) and heating value (47.02 MJ/kg vs. 43.48 MJ/kg). However, increasing biodiesel content in blends tended to increase fuel consumption and decrease efficiency due to biodiesel's lower heating value (39.62 MJ/kg) and higher viscosity (5.16 cSt vs. 2.58 cSt for bio-hydrogenated diesel). Emission analysis revealed that bio-hydrogenated diesel generally produced lower hydrocarbon, carbon monoxide, and smoke emissions than conventional diesel, though nitrogen oxide emissions were slightly higher. Biodiesel blends often showed increased emissions, particularly at higher blend ratios, due to poor fuel atomization. The Generalized Regression Neural Networks model demonstrated high accuracy in predicting engine performance and emissions, with coefficient of determination (R2) values exceeding 0.98 and mean absolute percentage errors below 5%. Optimization results indicated that bio-hydrogenated diesel ratios centered around 90% provided the best balance of performance and emissions. This research bridges critical gaps in combined bio-hydrogenated diesel and biodiesel usage and artificial intelligence-driven biofuel optimization, providing valuable insights for practical implementation in Thailand's agricultural sector.

Investigation and optimisation of performance and emission data of CI engine ternary blends under distinct conditions

This study investigates the significance of isoamyl alcohol (IAA) in a CI engine by blending with watermelon seed biodiesel (WSB) at preheating and varying load, injection timing (IT), and exhaust gas recirculation (EGR). Adaptive-Network Based Fuzzy Inference Systems (ANFIS), and Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) methods were employed to analyze the test results. From statistical indices data, the ANFIS models predicted more accurately. TOPSIS technique confirmed the preheated optimum ternary blend (POTB) as load-12 kg, WSB-5 %, IAA-15 %, IT-25° bTDC, and EGR-21 %. The closeness coefficient values model R2 = 0.9736. In comparison to diesel, thePOTB blend (WSB5IAA15) offers lower viscosity, density, CN, and heating value, with higher oxygen and latent heat of vaporization (Lv), most of which contribute to improved atomized spray and better combustion. Hence, at load-80 %, POTB to diesel results decrease BTE by 0.11 %, CO by 25 %, CO2 by 16.39 %, NOx by 37.08 %, and smoke by 16.16 %, while increasing BSEC by 0.40 %, and HC by 39.83 %. Further, at load-100 %, the results of POTB to diesel diminish BTE by 2.12 %, CO by 14.29 %, CO2 by 32.89 %, NOx by 58.12 %, and smoke by 38.13 %, while elevating BSEC by 7.57 %, and HC by 31.30 %. IAA exhibits elevated levels of oxygen, energy density, Lv, and OH active radicals, accompanied by reduced heating value and CN. IAA is crucial in lowering NOx and smoke levels, which are difficult for WSB to control on its own. Lastly, plots are illustrated for each response parameter to dominant (EGR and WSB) concerning ternary blends and diesel data for specific conditions. Ultimately, the POTB demonstrated that it can serve as an effective diesel fuel substitute.

Improving syngas yield and quality from biomass/coal co-gasification using cooperative game theory and local interpretable model-agnostic explanations

The co-gasification of waste biomass and low-quality coal to produce syngas as fuel is an effective and sustainable approach in the waste-to-energy paradigm. The modeling of this process is however complex and time-consuming. The data-driven machine learning (ML) approaches enhanced with explainable artificial intelligence (XAI) are capable of solving this issue. Hence, in this study, five different ML techniques including Linear Regression (LR), Support Vector Regression (SVR), Gaussian Process Regression (GPR), Extreme Gradient Boosting (XGBoost), and Categorical Boosting (CatBoost) were employed for the model-prediction. The ultimate analysis, proximate analysis, and operation setting data were employed for the control factors syngas yield and lower heating value (LHV) prediction. The prediction results showed that XGBoost was superior to other ML approaches with an R2 value of 0.9786, mean squared error (MSE) of 10.82, and mean absolute percentage error (MAPE) of 9.8% during model testing of the syngas yield model. In the case of the syngas LHV model an R2 value of 0.9992, MSE of 0.03, and MAPE of 0.83% was observed. XGBoost was superior for both syngas yield and LHV models. The analysis of feature importance and its quantification was conducted by Shapley Additive Explanations (SHAP) and Local Interpretable Model-agnostic Explanations (LIME). SHAP and LIME approaches revealed that reaction temperature and biomass mixing ratio were the most important control factors for the syngas yield model.

Investigation on co-gasification performances of sewage sludge and polyolefins by thermogravimetric analyze and two-stage fixed bed reactor

Co-gasification of biomass with hydrogen-rich feedstock is a promising method to improve H2 yield. Thus, in this work, co-gasification performances and corresponding promotion/inhibition effects of sewage sludge (SS) and three types of polyolefins (PE, PP and PS) were investigated in the thermogravimetric analyze and two-stage fixed bed reactor. Thermogravimetric experiments results indicated that with the addition of polyolefins, the initial temperature of blends progressively elevated, while its terminal temperature declined, suggesting that adding polyolefins facilitated the decomposition of samples. The thermal degradation of blends was distinguished into two stages, and in the first stage, a negative interaction was found at 25 % polyolefins mass ratio, but a positive interaction was occurred at 50 % and 75 % polyolefins mass ratios. Meanwhile, in the second stage, a negative interaction was obtained for blending with PE, whereas an opposite result was observed for blending with PP or PS. Therefore, temperature, feedstock and mixing ratio interacted on synergy effects between SS and polyolefins. Besides, two-stage fixed bed experiments results suggested that a higher gasification temperature was beneficial for the production of syngas, particularly the H2 yield, and blending with polyolefins into SS enhanced the H2 content, with PE performing best. The synergy interactions between SS and polyolefins accelerated the concentrations of H2 and CH4, while declining the CnHm yield, demonstrating a stronger re-cleavage of macromolecules. Furthermore, the low heat value of syngas and carbon conversion efficiency for all the samples separately elevated and reduced with rising gasification temperature and polyolefins mass ratios. At 800 °C, the highest gasification efficiency of samples could be achieved with the addition of 50 % PP or PS. This study provides a basis for the application of SS and polyolefins co-gasification.

Experimental study and characterisation of a novel two stage bubbling fluidised bed gasification process utilising municipal waste wood

Biomass gasification has increased due to its ability to provide high-temperature heat, making it promising for the decarbonisation of industrial processes. The economic and technical challenges of large-scale operations need to be addressed by focusing on small-sized gasifiers, while the use of low-grade biomass, is essential to increase the flexibility and sustainability of the plant. However, the utilisation of low-grade biomass is hindered by challenges stemming from variations in the particle distribution and shape, which significantly impact the fluidisation process and overall. In this research, the gasification of shredded municipal waste wood in a pilot-scale bubbling fluidised bed reactor was demonstrated, and the fluid-dynamics and gas production were assessed. The gasification process was yielding a gas with a lower heating value between 3.5MJNm−3 and 3.9MJNm−3 and a cold gas efficiency (CGE) of 46.4 %–48.6 %. Notably, these CGE values are consistent with pilot-scale setups, where CGE values above 50 % are typically not achievable because of poor insulation standards. The reactor's conical shape facilitated dynamic fluid regime transitions, ensuring efficient gas-solid interactions. This design allowed optimisation of fluidisation by accommodating particles of varying sizes throughout the reactor's height, thereby promoting efficient gasification suitable for industrial applications with diverse biomass feedstocks.

Biofuels and Their Blends—A Review of the Effect of Low Carbon Fuels on Engine Performance

Energy is an important aspect concerning global economic development and environmental conservation. Economic growth has been accompanied by extensive use of fossil fuels, resulting in significant emissions of greenhouse gases and other pollutants. Therefore, researchers have turned their attention to low/zero carbon fuels. Among these, biofuels have attracted wide attention due to their relatively low cost, clean combustion products and renewability. This article reviews the combustion, performance and emission characteristics of internal combustion (IC) engines fueled with biofuels categorized into three generations by their raw material sources. According to most research findings, biofuels generally exhibit poorer combustion performance in IC engines compared to fossil fuels due to their high viscosity and low lower heating value. However, these biofuels, characterized by a high oxygen content, facilitate more complete combustion and reduce emissions of CO, UHC and smoke, albeit increasing NOx emission and fuel consumption. Both thermal efficiency and brake power also tend to decrease, but various optimization strategies such as advanced combustion modes or injection control methods can partially compensate for these drawbacks. In conclusion, biofuels should be a promising low-carbon fuel for IC engines in the future.

Thermodynamic Approach to Optimal Water Management for Fuel Cell Electric Vehicles

A systematic, multicomponent model has been developed to investigate optimal water management for fuel cell electric vehicles. The water management strategies focus on manipulating thermodynamic states to provide the adequate requirements of fuel cells. A pseudo-2D fuel cell water transfer model, a shell and tube type membrane humidifier model, and a centrifugal compressor model are mathematically developed and solved using MATLAB to achieve an integrated thermodynamic approach based on system piping and instrumental diagrams(P&ID). Each component model is validated using published experimental data with good agreement. In the air supply system, the required humidity at the fuel cell channel inlets is theoretically predicted under low heating value operating fuel cells. Subsequently, the optimal mass flow rate of the compressor is suggested to cover a wide range of conditions. Additionally, the recirculated gas is bypassed to control the humidification levels of the humidifier based on the required humidity at the fuel cell channel inlets. The results show the thermodynamic states within system in accordance with the optimal operation conditions of the component. This systematic approach presents significant algorithms for optimizing water distributions in vehicular fuel cell systems.

Numerical simulation and experimental study of hydrogen production from chili straw waste gasification using Aspen Plus

Biomass gasification is a promising method for hydrogen production. This study systematically models the gasification of chili straw waste (CSW) using the Aspen Plus simulator, focusing on the effects of gasification agents—steam, air, and oxygen—and sensitivity analyses of key parameters. Results show that under optimal steam gasification conditions, with a temperature of 700 °C and atmospheric pressure, hydrogen concentration reached 59.61%, while the lower heating value (LHV) decreased to 6.65 MJ/m3 due to CO reduction. In air gasification, increasing air input reduced hydrogen and CO concentrations by 18.5% and 26.6%, respectively, while LHV dropped by 52.5%. Oxygen-enriched gasification significantly improved hydrogen and CO concentrations, increasing LHV by 129.4% as the oxygen fraction rose. Sensitivity analysis revealed that optimal hydrogen production in air-steam gasification occurred with a low equivalence ratio of 0.18, moderate temperature around 700 °C, and atmospheric pressure. These findings highlight the critical role of temperature, pressure, and gasifying agents in optimizing hydrogen production, providing a basis for improving the efficiency of biomass gasification systems.

Aeration Optimization for the Biodrying of Market Waste Using Negative Ventilation: A Lysimeter Study

This study investigates the optimization of aeration rates for the biodrying of market waste using negative-pressure ventilation. Market waste, characterized by a high moisture content (MC) and rapid decomposition, presents challenges in waste management. Over 12 days, three aeration rates (ARs) of 0.2, 0.4, and 0.6 m3/kg/day were examined, and the most effective continuous ventilation configuration was identified in terms of heat generation, moisture reduction, and biodrying efficiency. The results indicate that the most effective AR for heat retention and moisture removal was 0.2 m3/kg/day, achieving a 6.63% MC reduction and a 9.12% low heating value (LHV) increase. Gas analysis showed that, while AR 0.2 supported high microbial activity during the initial 7 days, AR 0.6 sustained higher overall CO2 production due to its greater aeration rate. The findings also suggest that the biodrying of market waste with a high initial MC can achieve significant weight loss and leachate generation when paired with a high aeration rate of 0.6 m3/kg/day, with a 69.8% weight loss and increased waste compaction being recorded. The study suggests that variable ARs can optimize biodrying, making market waste more suitable for conversion to refuse-derived fuel or landfill pre-treatment and improving waste-to-energy processes and sustainability.

Experimental Investigation of Ammonia/Oxygen/Argon Combustion: The Role of Equivalence Ratio and Nozzle Shape in a Constant Volume Combustion Chamber with Sub-chamber

The global rise in carbon emissions presents a rising challenge for current and future generations. In the pursuit of zero carbon emissions, ammonia (NH3) has emerged as an attractive alternative energy source. Ammonia offers a carbon-free fuel option with a higher energy density than liquid hydrogen while maintaining ease of transport and storage. However, ammonia still has its drawbacks, such as a high autoignition temperature, slow burning velocity, and low heating value, that demand further investigation of its combustion characteristics. This experiment was done to study the effect of nozzle shape and equivalence ratio (ɸ) on the combustion of an ammonia/oxygen/argon mixture using a constant volume combustor equipped with a sub-chamber. The fuels were premixed for 10 minutes and conditioned to an initial pressure of 0.2 MPa and an initial mixture temperature of 423 K. The results show that the different nozzle shapes each have their advantages in terms of pressure and jet speed. Overall, the lean mixtures (ɸ0.6 and ɸ0.8) consistently performed better compared to the stoichiometric mixtures (ɸ1.0) in all categories investigated in this study. The round nozzle generates higher pressure, while the special shape nozzle enhances jet speed, highlighting trade-offs between the two.