Biomass Gasification Research Articles

Experimental and simulation study on coal-fired power generation coupling with fluidized bed biomass gasification

Positive-pressure fluidized bed technology utilizes the pressure generated by biomass gasification to facilitate further combustion within the furnace. This technique addresses the safety risks associated with external pressure in fluidizing medium and high-temperature situations and reduces equipment investment and operating expenses. However, research on the effects of the positive-pressure process in fluidized beds on gasification coupled with coal-fired power generation systems is scarce. To fill this research gap, extensive experimentation and Aspen Plus simulation were conducted to investigate the impact of equivalence ratio (ER), gasification pressure, and gasification temperature on the gasification performance. A 660 MW coal-fired boiler model was established to reveal the coupling effect on flue gas temperature and thermal efficiency by gasification from a positive-pressure fluidized bed on the boiler, and its accuracy was proved by comparing the actual boiler design parameters. The power generation cost of the positive-pressure gasification coupled coal-fired power generation system is calculated with the established model. The results indicate that an increase in gasification pressure from 4000Pa to 8000Pa resulted in no significant change in the operating indicators of the boiler, with the tail gas temperature near 132 °C and a boiler thermal efficiency of 92.68 %. Gas yield, carbon conversion rate, and gasification efficiency were positively correlated with gasification temperature and ER. However, the heat value of combustible gas increased with the gasification temperature and decreased with an increase in ER. With the rise of the biomass gas blending ratio, the power generation cost of the unit gradually decreases. Respectively, the positive -pressure would lower the power generation costs of a 660 MW coal-fired boiler by 5.76 × 105$/year. This study demonstrates that positive-pressure fluidized bed gasification may retain high gas yields and efficiency, significantly lowering equipment investment and operating expenses, as a very efficient energy-saving and carbon-reduction technique.

Production of syngas from oil palm shell biomass using microwave gasification

The research work on microwave gasification (MWG) is limited in the literature compared to pyrolysis, and little attention has been paid to its efficiency. The present study aims to investigate the effect of MW power (20–40 %) and absorber loading (0–15 wt%) on the temperature, gas composition, syngas yield, quality, and efficiencies during gasification of oil palm shell biomass in a 1.25 kW and 2.45 GHz lab-scale microwave (MW) system. Overall, the yield and quality of syngas increased with MW power, but it decreased after reaching optimum absorber loading. The highest product gas (63.3 wt%) with a heating value of 11.66 MJ/m3 was obtained at an optimum process condition (absorber loading of 10 wt% and MW power of 40 %). Under these conditions, the heating rate of 17 °C/s and maximum syngas (CO + H2) (76.5 vol%) were recorded. The specific energy consumption increased with MW power but dropped with increasing absorber loading, demonstrating MWG to be more energy efficient at higher biomass loading. MW process efficiency (19.7 %) and biomass conversion efficiency (55.6 %) were achieved at optimum process conditions while considering syngas only. The MWG system can become more energy and process-efficient if all byproducts are utilized and scaled up.

Multi-objective optimization of a dual fuel CI engine powered with syngas and pilot diesel using TLBO algorithm: A metaheuristic approach

Abstract The thermochemical conversion of biomass into producer gas presents an attractive alternative fuel option for compression ignition (CI) engines, making biomass gasification a critical driver for achieving sustainable development goals. Considering the application of producer gas (PG) in CI engine, the most potential gases include H2 and CO as main fuel compounds and it is crucial to comprehensively understand the impact of these two gas components on the engine behaviour. Nowadays, artificial intelligence-powered models are frequently applied for simulating engines that run on a single type of fuel. However, their usage is not as common when it comes to modeling dual-fuel CI engines run on synthetic producer gas or syngas. The present study explores the feasibility of optimizing operational parameters, such as engine load and syngas composition, in improving the efficiency and lowering the levels of pollutants emitted by a 3.5 kW CI engine operated under dual fuel (DF) mode using syngas as primary fuel and diesel as pilot fuel. The performance and emission characteristics of syngas (H2:CO) is examined by studying its behaviour in four different combinations. The compositions of syngas are prepared based on the volumetric percentage of the H2 and CO and is inducted into the combustion chamber using a novel venturi-type air-gas mixer. In the present study, an intelligent metaheuristics-based optimization algorithm i.e., Teaching–Learning Based Optimization (TLBO) is developed and introduced, to develop a predictive model within constrained range of engine operating conditions. Further, the algorithm is used to estimate multiple engine performance characteristics simultaneously viz., brake thermal efficiency (BTE), unburned hydrocarbons (HC), and carbon monoxide (CO). The resultant findings identify the optimal engine load of 68.87% and the ideal syngas composition of 63.9% H2 and 49.5% CO as key parameters for maximizing engine efficiency while minimizing exhaust emission. At these optimized operating condition, 19.49% BTE is observed, while HC and CO emission was found to be 384.6 ppm and 445.33 ppm respectively. This shows the effective and efficiency of the proposed algorithm.

Effects of Na-salt solutions on the biomass pyrolysis and CO2-assisted gasification behavior

This study aims to explore the effects of different Na-salt solutions on the behavior of biomass pyrolysis and gasification. The same molar number of Na was introduced via the impregnation method. The distinction was that pine wood impregnated with neutral NaCl and Na2SO4 solutions was the Na in physical adsorption form, whereas the alkaline Na2CO3, CH3COONa, and NaOH solutions resulted in both carboxylate form and physical adsorption form. Thermogravimetric analysis results showed that impregnating alkaline Na solution was more potent than the neutral Na solution in reducing the thermal stability of pine wood structures. Results of pyrolysis and CO2-assisted gasification indicated that samples impregnated with the alkaline Na solutions obtained lower CO and higher CO2 evolution than that from the neutral Na solution during pyrolysis. The Na in carboxylate form was more difficult to volatilize, and formed more Na-containing active catalytic structures, resulting in biochar that provided higher reactivity in gasification. However, different Na solutions on the biochar's gasification reactivity showed the order of NaCl-loaded sample < CH3COONa-loaded sample ∼ NaOH-loaded sample < Na2SO4-loaded sample < Na2CO3-loaded sample. This can be attributed to the combined effects of Na-containing active catalytic structures, along with the active surface salt complex formed by molten Na species and biochar. As for the overall energy efficiency of pine wood impregnated with different Na solutions, gasification of Na2CO3-loaded sample provided the highest maximum overall energy efficiency (49.2 %). The results presented here provide useful insights for practical application of using syngas for electricity generation.

Modeling of a heat-integrated biomass downdraft gasifier: Influence of feed moisture and air flow

A model for a heat-integrated biomass downdraft gasifier is developed and used to study the influence of changes in biomass moisture content and gasifier air flow. This one-dimensional steady-state model accounts for pyrolysis, combustion and gasification reaction kinetics as well as transport phenomena occurring within the gasifier and heat integration system. The gasifier is divided into four zones for solving the ordinary differential equations (ODEs), because each zone has different geometry for the reactor or heating system. The material and energy balance ODEs are solved as a boundary value problem (BVP), ensuring that conditions for the producer gas at the bottom of the reactor match the conditions of the countercurrent annulus gas, which is used for heating. The model also accounts for the preheating of the biomass using exhaust gas from an associated engine used to generate electricity from the producer gas. The model predicts the process gas temperature, flow rate and composition and was validated using two experimental runs with different control inputs. The model predictions show good agreement with the data. Simulations with the highest feed moisture result in lower reactor temperatures and simulations with the highest air flow result in the highest reactor temperatures.

Decarbonization frameworks to industrial-scale ammonia production: Techno-economic and environmental implications

Ammonia production traditionally relies on steam methane reforming (SMR), but it emits carbon and harms the environment. To address decarbonization frameworks of industrial-scale ammonia production process, a 100,000-ton ammonia manufacturing plant is presented using green ammonia synthesis methods. This study presents two promising hydrogen production methods for ammonia production, utilizing water electrolysis as scenario 1 and biomass gasification as scenario 2, while nitrogen is supplied using a cryogenic air separation unit (CASU). The techno-economic analysis shows that the ammonia production via SMR as the base case has lower total costs than Scenarios 1 and 2 due to not using green electricity. Through the environmental impact assessment of climate change, ozone depletion, terrestrial ecotoxicity, and natural land transformation, it is shown that Scenario 1 has lower impacts than the base case and Scenario 2 due to using green electricity. It is noted that the base case and Scenario 1 ensure the lowest production cost and environmental impacts, respectively, and Scenario 2 is the best balance between the economy and the environment.

Data analysis and machine learning aided integrated catalyst activity and process modelling for selective H2 production from biomass gasification

Hydrogen energy derived through biomass gasification is considered as one of the most sorted sustainable sources of renewable energy. This process enhances the H2 production from biomass in the presence of specific catalysts. Among different kinds of models that have been employed for this process, ML models adept at approximating non-linear functions and facilitate outcome prediction without detailed mathematical descriptions. Thus, the current work focuses on understanding structural-composition-operating-target property relationships, and integrated catalyst and process modelling using ML framework for thermo-catalytic biomass gasification to H2 production, and demonstrates outliers handling, data normalization for efficient handling of data-driven modelling with non-linear database. Linear, tree-based, kernel-based, and ANN models were developed with 589 datapoints screened from the 59 relevant papers with 24 inputs and 4 outputs (H2, CO, CO2, and CH4 as vol. %). Performance of these models are evaluated through 5-fold cross-validation and test data with the help of statistical measures. ANN with Basian-regularization learning algorithm using tan-sigmoid activation function in both layers, resulted superior performance in prediction of H2 production (RMSE = 6.85 & R2 = 0.80) and other output gases with high accuracy (i.e., minimum deviation from experimental data) compared to other ML models. Further, using the best ML model, input contribution and PDP analysis were performed to interpret the significance of predominate input parameters affecting on the product composition. Feature contribution analysis reveals that temperature, S/B ratio, catalyst support type, and sulphur content in biomass are significant parameters for enhancing H2 production from catalytic-biomass gasification, and PDP analysis discloses their optimal operating region.

Investigation of a new holistic energy system for a sustainable airport with green fuels

The advancement of sustainable solutions through renewable and clean energy sources is considered crucial to mitigate carbon emissions. This study reports a novel system developed for an airport utilizing geothermal, biomass, and PV solar energy sources. The proposed system is capable of producing five useful outputs, including electrical power, hot water, hydrogen, kerosene, and space heating. The system proposed in the study is further considered for the Vancouver Airport in British Columbia, Canada using the most recent available data. The geothermal sub-system introduced in this study is also unique, which utilizes the carbon dioxide captured from biomass gassification as the heat transfer medium for geothermal heat to the Rankine cycle for power generation and heating. The present system is modeled and analyzed using thermodynamic method through energetic and exergetic approaches to determine the variation in system performance based on different annual environmental conditions. The biomass gasification and kerosene production are evaluated based on the Aspen Plus models and simulation. The efficiencies of the geothermal system with the carbon dioxide reservoir are found to have energetic and exergetic efficiencies of 78% and 37% respectively. The total hydrogen production is potentially estimated to be 452 tons on an annual basis. The kerosene production mass flow rate is reported as 0.112 kg/s. The overall energetic and exergetic efficiencies of the system are found to be 41.8% and 32.9% respectively. Moreover, this study offers crucial information for the aviation sector to adopt sustainable solutions more effectively.

Assessing the exergy sustainability of a paddy drying system driven by a biomass gasifier.

Paddy parboiling in rice industries is an energy-intensive process that requires huge attention for energy conservation, fuel economy, and sustainability. Thus, several research initiatives have been undertaken to adopt a suitable energy conversion system in such industries to improve thermal efficiency and reduce environmental impact. In this study, exergy performance and exergy-based sustainability indicators have been investigated on a reversible bed paddy dryer coupled with a rice husk-fuelled downdraft gasifier. The experiment was conducted at the optimum operating conditions such as an equivalence ratio of 0.2 in the gasifier and a drying air temperature of 80℃ in the dryer. The exergy efficiency of the reversible bed dryer and the gasifier were 65.53% and 70.92% respectively. The lowest exergy efficiency of 35.29% was seen in the combustion chamber since a huge exergy destruction of 2.75kW occurred. Therefore, the combustion chamber has a high potential improvement of about 1.66kW. Due to less exergy destruction, the gas cooler and air duct showed high exergy efficiency of 62.36% and 76.2% respectively and the lowest values in exergy-based sustainability indicators. The assessment of environmental and sustainability factors on each component showed that the combustion chamber has a high waste exergy ratio of 0.688, environment effect factor of 1.95, exergy destruction coefficient of 0.69, and exergy sustainability index of 0.51.

Modeling of a Biomass Cogeneration Plant from a Gasification Process

In recent decades, growing energy demand, coupled with concerns about climate change, has led to the exploration of sustainable energy sources. Among these, biomass gasification stands out as a promising method for generating heat and power. This research delves into the potential impact of biomass gasification within the global energy landscape, focusing particularly on its application in cogeneration plants. Utilizing Aspen Plus software V10, this study undertook the modeling and optimization of a biomass cogeneration plant. Through simulation, it was found that a biomass flow rate of 5 kg/s yielded 6.172 MW of power output. Additionally, the study revealed several key factors that influence power generation: increasing biomass and airflow rates, increasing gasification temperature, and reducing water flow rate. By doubling the biomass flow rate to 10 kg/s and increasing the temperature to 800 °C, power generation increases by 41.75%. Moreover, the study demonstrates that Portuguese municipal waste is an efficient source of energy production, with higher cold gas and overall efficiencies compared to forest and vine-pruning residues.

Usage of Biomass Gasifier for Drying Soaked Paddy in a Reversible Airflow Flatbed Dryer: Artificial Neural Network Modelling

Usage of Biomass Gasifier for Drying Soaked Paddy in a Reversible Airflow Flatbed Dryer: Artificial Neural Network Modelling

Utilization of Waste Banana Peels and Corn Cobs as Substrates in Neurospora sitophila Fermentation for Production of Natural Yellow Dyes

In the current situation, biomass gasification has become a major interest in producing clean energy and green chemicals. By gasification, the biomass can be converted to synthetic gas (syngas) for many purposes. However, syngas with high tar content can cause pipeline fouling and disturb the operation of downstream equipment. To reduce tar content, a two-series wet scrubber was installed for syngas cleaning produced by palm kernel shell gasification. Firstly, the gasification is operated at a temperature range of 500 – 600oC and 700 – 800oC to determine the conditions where the lowest tar syngas is produced. After that, the wet scrubber is installed with a variety of solvents including isopropyl alcohol, water, used cooking oil, and used lubricating oil. The results show that the lowest tar syngas was produced at a temperature of 800oC with a tar yield of 0.165 g/kg biomass. Meanwhile, in the same condition, isopropyl alcohol delivers the most substantial impact on tar removal efficiency, whereas used lubricating oil results in less impact. The use of isopropyl alcohol resulted in 99.25% tar removal effectiveness while lubricating oil yielded just 50.32%.

Tar Removal of Palm Kernel Shell Syngas using Wet Scrubber

In the current situation, biomass gasification has become a major interest in producing clean energy and green chemicals. By gasification, the biomass can be converted to synthetic gas (syngas) for many purposes. However, syngas with high tar content can cause pipeline fouling and disturb the operation of downstream equipment. To reduce tar content, a two-series wet scrubber was installed for syngas cleaning produced by palm kernel shell gasification. Firstly, the gasification is operated at a temperature range of 500 – 600oC and 700 – 800oC to determine the conditions where the lowest tar syngas is produced. After that, the wet scrubber is installed with a variety of solvents including isopropyl alcohol, water, used cooking oil, and used lubricating oil. The results show that the lowest tar syngas was produced at a temperature of 800oC with a tar yield of 0.165 g/kg biomass. Meanwhile, in the same condition, isopropyl alcohol delivers the most substantial impact on tar removal efficiency, whereas used lubricating oil results in less impact. The use of isopropyl alcohol resulted in 99.25% tar removal effectiveness while lubricating oil yielded just 50.32%.

Feasibility of sustainable reusability of Ni/char catalyst for synthetic gas production via catalytic steam gasification

Ni/char catalyst is one of the most promising catalysts for enhancing gas production, particularly syngas from catalytic steam gasification of biomass. In the current study, one unmodified (Ni/MMchar) and two modified catalysts (Ni/NaMMchar and Ni/NaAceMMchar) were utilized to investigate the reusability potential of Ni/char catalyst for catalytic steam gasification of bamboo in a two-stage fixed-bed reactor including the changes in catalyst characteristics. N2 adsorption-desorption by BET, scanning electron microscope connected with energy-dispersive X-ray spectrometer (SEM-EDS), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analyses were utilized for examining their characteristics. The findings indicated that the three catalysts could maintain the reusability potential in catalytic steam gasification of bamboo for twice cycles. The syngas reduction percentages in the second cycles of the catalysts ranged between 11.0 and 22.8 %. H2/CO ratios of all spent catalysts lined in the range of 4.10 − 2.45. The low heating values of syngas products were in the range of 8.83–8.19 MJ/Nm3. Considering the catalyst characteristics, the increasing cycles of catalyst operations induced carbon deposition, resulting in the reduction of specific surface areas. SEM-EDS images of the used catalysts appeared the coke layer and the Ni metal sintering on the surfaces. The uses of catalysts encouraged the transformation of Ni metal active site into NiO, Ni2O3 and Ni3C forms. These phenomena were the major causes of catalyst deactivation. The changes in the characteristics and catalyst activity controlled the gasification reactions, resulting in the catalyst deactivation and gaseous products.

A new strategy to produce calcium carbide-acetylene from integrated multi-level low carbon construction driven by biomass

A highly efficient and clean biomass energy-based calcium carbide-acetylene production system, including low-carbon energy supply, solid waste recycling and cascade utilization of waste heat, has been developed for the conventional energy-intensive and highly polluting fossil fuel-dependent calcium carbide industry. This system supplies the carbide-acetylene production plant with energy from the gasification of biomass and converts the plant's solid waste carbide slag into the calcium feedstock required by the plant. The waste heat from the plant's high-temperature exhaust gases is recycled and used via the multi-stage heat exchange, so that the energy cascade conversion and utilization is achieved. A simulation model of the plant is created in Aspen Plus, and a mathematical model for the biomass gasification process and cycle compensation of the calcium source through the Fortran language is written and embedded. When calculating the carbon consumption and CO2e emissions of the system, it was found that the carbon consumption and CO2e emissions of the conventional process were 5.43 t Coal·t−1C2H2 and 2.25 t CO2e·t−1C2H2, respectively. However, the carbon consumption of the new process was reduced by 65.19%, and carbon emissions by 27.24% in comparison. The energy analysis shows that the energy efficiency of the system is 36.21% for the conventional process and 44.82% for the new processes. The exergy analysis of the effective energy shows that the exergy efficiency of the new process is 73.20%, which is 52.98% better than that of the conventional process. Introduction of an index, the levelized income of acetylene product (LIOA), to characterize the product income of the system. When the price of acetylene is between 2.23 $/kg and 4.19 $/kg, the LIOA for the conventional and the new processes are 1.41 $/kg to 3.38 $/kg and − 1.28 $/kg to 0.68 $/kg, respectively. It is worth noting that the critical price (PCC2H2) for products generating net revenue from the new process is 3.17 $/kg. This study is of great importance for the development of a low-carbon biomass-coupled calcium carbide-acetylene process.

Evaluation and selection of sustainable hydrogen production technologies with unknown expert weights based on extended MARCOS under hybrid information

The selection of sustainable hydrogen production technologies (HPT) is a paradigm transformation for industrial enterprises to pursue commercial benefits and environmental performance, which has increasingly attracted the attention in academic circles. Therefore, the chief orientation of this research is to construct a novel sustainability-oriented decision-support framework for hydrogen production system. Firstly, an approach is developed to determine expert weights under each criteria in a linguistic environment. Secondly, the Measurement of Alternatives and Ranking according to Composite Solution (MARCOS) method is extended to prioritize sustainable HPT under hybrid information (HMARCOS). Finally, a case study of 5 typical HPT regarding 15 sustainability indicators is conducted. The results display the biomass gasification has the highest sustainability priority for hydrogen production compared with wind turbine electrolysis, photovoltaic electrolysis, steam methane reforming and coal gasification. Furthermore, the reliability and availability of the integrated framework is demonstrated by the comparisons with other approaches.

Modeling and thermodynamic optimization of distributed combined heat and power system based on biomass chemical looping hydrogen generation process

Distributed biomass combined heat and power (CHP) system is becoming an important way to use local biomass for ensuring regional energy supply and reducing CO2 emissions. In this work, a high-efficient CHP system based on a new separated-type biomass gasification process is proposed. The gasification system includes a chemical looping hydrogen generation (CLHG) process combined and a tar catalytic steam reforming (TCSR) unit, in which the general CLHG process includes a fuel reactor (FR), a steam reactor (SR) and an air oxidation reactor (AR), but in this study, the AR is removed and instead, the FR is decoupled into two reaction stages, namely, pyrolysis and gasification. In addition, the biomass pyrolysis-gasification-hydrogen generation (BPGH) combined cycle system is established by using oxygen carrier to couple pyrolysis, gasification and hydrogen generation stages. The TCSR process is used to convert volatiles generated by pyrolysis into syngas. To maximize thermodynamic efficiency of the system, the influences of temperature for the catalytic steam reforming (TCSR) and the ratio of steam to carbon (S/C) on the overall energy and exergy efficiency are mainly studied. The results show that the overall energy and exergy efficiencies reach the highest values of 75.93% (LHV) and 32.61%, respectively, when TSCR=800 °C and S/C = 3 while the net power generation energy and exergy efficiencies are 27.43% (LHV) and 27.54%, respectively.

Microwave driven steam reforming of biomass model tar based on metal organic frameworks (ZIF-67) derived Co/C catalyst

Tar catalytic removal is a key issue in biomass gasification, which is suffering from catalyst coking and sintering. Microwave technology is attractive due to the high activity on polar molecules and ability to lower activation energy. In this study, the Co/C derived from metal-organic frameworks (ZIF-67) was developed as a bifunctional microwave catalyst that can strengthen the interaction between microwave and tar catalytic reforming, and enhance the anti-coking and sintering ability. The effects of the temperature, heating method, tar concentration, and catalyst support on model tar conversion rate were investigated. The operating conditions at 700 °C and tar concentration lower than 20 g/m3 can reach a promising conversion rate over 90.15 % under microwave irradiation. On the one hand, microwave heating groups performed better in conversion rate and coking compared to conventional heating, due to the active species generated from the microwave plasma. On the other hand, Co/C showed better performance in catalytic activity and sintering stability, due to the highly dispersion of cobalt nanoparticles and the confinement effect of carbon nanotubes on the catalyst surface. These findings proposed a novel approach for efficient biomass tar removal under microwave irradiation, and offered a potential tool to further reveal the mechanism in microwave driven tar steam reforming system.

Hydrogen production from woody biomass gasification: a techno‐economic analysis

Hydrogen production from woody biomass gasification: a techno‐economic analysis

Experimental Biomass Gasification in Updraft Gasifier with Gas Outlet at Reduction Zone and Air Supply using Suction Blower

Rice husk gasification is increasingly attractive, particularly with updraft gasifier type, because of its simple construction and ease of operation. However, updraft gasifier has a disadvantage of generating substantial amounts of tar. Tar will decompose into combustible gas when exposed to high temperatures. The reduction zone has a high temperature for tar decomposition to occur. Therefore, in this research, updraft gasifier was modified by positioning gas outlet at the reduction zone and inducing gasification air supply using a blower. Modifications are made by moving the gas outlet from the top to the middle or reduction area. The initial start-up of the system uses a blown air supply system, then after the syngas are produced by the operation, it is replaced with a sucked air supply. Two blowers are used, namely an exhalation or blowing blower for initial start and a suction blower for continuous operation. The fuel used was low bulk density, specifically rice husks. The aim was to characterize the modified gasifier, focusing on parameters such as operating time, duration of gas combustion, air-to-rice husks ratio, and flame color. Typically, the experiments were conducted under constant of air velocity and fuel quantity. The results showed that the average operating time, duration of flammable gas, and air-to-rice husks ratio were 74.25 minutes, 52.28 minutes, and 7.6 kg air/kg husk, respectively, and the flame produced was a bluish-yellow color that indicates a reduction tar.