Direct Combustion Of Biomass Research Articles

Predictive modelling of drag, lift and torque coefficients of cylindrical biomass particles under artificial intelligence

The escalating threats of climate change and fossil fuel depletion have greatly spurred the widespread utilization of renewable energy sources. Biomass energy stands out as the most abundant renewable energy resource. Among all biomass conversion technologies, direct combustion of biomass for heating and power generation represents the most common and cost-effective approach. Suspended combustion technology is widely employed in existing biomass combustion power plants worldwide. However, conventional modeling procedures often fail to adequately address the differences between coal and biomass combustion, particularly the significant impact of large-sized and highly non-spherical cylindrical straw biomass particles on their trajectories. This study utilizes OpenFOAM-body-fitted mesh direct numerical simulation (DNS) to generate a Computational Fluid Dynamics (CFD) dataset consisting of 300 data points for cylindrical particles, aimed at constructing a prediction model based on machine learning (N+1) for key aerodynamic parameters (drag coefficient, lift coefficient, and torque coefficient). The proposed model enables precise prediction of aerodynamic parameters for a wider range of different cylindrical particles and flow conditions, thus extending the existing Euler-Lagrangian model for non-spherical biomass multiphase flow.

Life Cycle Assessment of Wheat Straw Pyrolysis with Volatile Fractions Chemical Looping Combustion

Among the approaches to facilitating negative CO2 emissions is biochar production. Biochar is generated in the pyrolysis of certain biomasses. In the pyrolysis process, carbon in the biomass is turned into a solid, porous, carbon-rich, and stable material that can be captured from the soil after a period of from a few decades to several centuries. In addition to this long-term carbon sequestration role, biochar is also beneficial for soil performance as it helps to restore soil fertility and improves the retention and diffusion of water and nutrients. This work presents a Life Cycle Assessment of different pyrolysis approaches for biochar production. Biomass pyrolysis is performed in a fixed-bed reactor, which operates at a mild temperature (550 °C). Biochar is obtained as solid product of the pyrolysis, but there are also liquid (bio-oil) and gaseous products (syngas). The pyrolysis gas is partly used to fulfil the energy demand of the pyrolysis process, which is highly endothermic. In the conventional approach, CO2 is produced during the combustion of syngas and emitted to the atmosphere. Another approach to facilitate CO2 capture and thus obtain more negative CO2 emissions in the pyrolysis process is burning syngas and bio-oil in a Chemical Looping Combustion unit. Life Cycle Assessment was performed of these approaches toward biomass pyrolysis to evaluate their environmental impact. The Chemical Looping Combustion approach significantly reduced the values of 7 of the 16 environmental impact indicators studied, along with the Global Warming Potential among them, it slightly increased the value of one indicator related to the use of fossil resources, and it maintained the values of the remaining 8 indicators. Environmental impact reduction occurs due to the avoidance of CO2 and NOx emissions with Chemical Looping Combustion. The CO2 balances of the different pyrolysis approaches with Chemical Looping Combustion configurations were compared with a base case, which constituted the direct combustion of wheat straw to obtain thermal energy. Direct biomass combustion for the production of 17.1 MJ of thermal energy had CO2 positive emissions of 0.165 kg. If the gaseous fraction was burned by Chemical Looping Combustion, CO2 was captured and the emissions became increasingly negative, until a value of −3.30 kg/17.1 MJ was generated. If bio-oil was also burned by this technology, the negative trend of CO2 emissions continued, until they reached a value of −3.66 kg.

Chemical Speciation, Leaching Behavior, and Environmental Risk Assessment of Trace Elements in the Bottom Ash from Biomass Power Plant.

Biomass combustion for power generation stands as a pivotal method in energy utilization, offering a promising approach for renewable energy utilization. However, the substantial volume of slag produced by biomass burning plants poses environmental challenges, impeding sustainable energy practices. This article systematically studies the characteristics of ash generated from typical biomass direct combustion power plant ash and analyzes the chemical composition, trace element content characteristics, leaching characteristics, and chemical forms of biomass bottom ash. Furthermore, it assesses the environmental ecology and bioavailability of trace elements in bottom ash using the ecological risk assessment method and RAC method. The results demonstrate that the biomass bottom ash contains plant nutrients, such as K, Ca, Mg, and P, while the content of harmful trace elements is lower than the relevant Chinese standards. In dissolution experiments, the leaching rate of nearly all elements remains exceptionally low, primarily due to the distribution of trace elements within the lattice structure of stable minerals. Trace elements predominantly exist in the residual phase, Cu and Zn primarily found in organic compounds and sulfide bound states, while other elements mostly exist in the form of iron manganese oxide bound states. Ecological risk assessment indicates a significant risk level for Cd, contrasting with the slight risk associated with other elements. RAC results indicated no ecological risk of all of the trace elements. Consequently, the utilization of bottom ash in agricultural and forestry soils is deemed to be viable. These findings serve as a crucial foundation for biomass bottom ash resource utilization and underpin the sustainable utilization of biomass energy.

Estimation of the main air pollutants from different biomasses under combustion atmospheres by artificial neural networks

The production of biofuels to be used as bioenergy under combustion processes generates some gaseous emissions (CO, CO2, NOx, SOx, and other pollutants), affecting living organisms and requiring careful assessments. However, obtaining such information experimentally for data evaluation is costly and time-consuming and its in situ obtaining for regional biomasses (e.g., those from Northeast Brazil (NEB) is still a major challenge. This paper reports on the application of artificial neural networks (ANNs) for the prediction of the main air pollutants (CO, CO2, NO, and SO2) produced during the direct biomass combustion (N2/O2:80/20%) with the use of ultimate analysis (carbon, hydrogen, nitrogen, sulfur, and oxygen). 116 worldwide biomasses were used as input data, which is a relevant alternative to overcome the lack of experimental resources in NEB and obtain such information. Cross-validation was conducted with k-fold to optimize the ANNs and performance was analyzed with the use of statistical errors for accuracy assessments. The results showed an acceptable statistical performance for all architectures of ANNs, with 0.001–12.41% MAPE, 0.001–5.82 mg Nm−3 MAE, and 0.03–52.30 mg Nm−3 RMSE, highlighting the high precision of the emissions studied. On average, the differences between predicted and real values for CO, CO2, NO, and SO2 emissions from NEB biomasses were approximately 0.01%, 10−6%, 0.14%, and 0.05%, respectively. Pearson coefficient provided consistent results of concentration of the ultimate analysis in relation to the emissions studied and effectiveness of the test set in the developed models.

CFD simulation study of a biomass pellet-fuelled boiler

Biomass energy is an important substitute for fossil energy. Direct combustion of biomass in the boiler has the problem of high emissions. In this paper, a 0.1 t/h biomass atmospheric pressure hot water boiler is used for CFD modeling, aiming at providing a low-cost and high-efficiency way for the study of biomass boilers. In this paper, the biomass pyrolysis process is divided into three processes: water evaporation, devolatilization, and coke combustion. Using the UDF function combined with a porous medium model to write code, the gas-solid combustion process in the boiler is realized, and the grate is used to split the air. The calculation results show that the model can accurately restore the temperature, velocity, and composition changes in the boiler. Compared with the actual results, the temperature difference between the furnace and the outlet is less than 20 K, and the modeling has achieved good results.

Experimental study on the sintering characteristics of biomass ash

The alkaline metal content in biomass is high, which leads to a low initial sintering temperature. Therefore, during the process of direct biomass combustion for power generation, there are serious problems such as ash deposition and slagging on the heating surface, which has become a technical bottleneck for the safe, stable and long-term operation of boilers. In industry, the melting characteristics of ash are commonly used to guide boiler design and operation. However, traditional measurement of ash melting temperature has a large subjective error, and the releasing of alkaline metals during the measurement process results bit higher value, which affects the accuracy of the measured characteristic temperature. Comparingly, the initial sintering temperature is lower than the deformation temperature of the ash. This article provides a device for measuring the sintering temperature of biomass ash by using the pressure drop method. A novel two ash chamber system was invented, in which the alkali element released from the first ash chamber was captured by the downstream second ash chamber to compensate the escaping of alkali element. The initial sintering temperature of the second ash chamber has more accuracy with lower value than that measured by the traditional single sample chamber. XRD was used to analyze the mineral composition and causes of sintering of the ash samples before and after sintering. The results show that the sintering mechanisms of different types of biomass are different. In addition, combined with SEM analysis of rice husk, fruit core, rapeseed straw, and corn straw, the results show that the initial sintering temperature of the ash samples measured by the double chamber measurement method is more accurate than that measured by the single chamber measurement method, further validating the reliability of the two ash column system.

Techno-Economic Assessment of an Innovative Small-Scale Solar-Biomass Hybrid Power Plant

The current context of the climate emergency highlights the need for the decarbonization of the energy sector by replacing current fossil fuels with renewable energy sources. In this regard, concentrating solar power (CSP) technology represents a commercially proven alternative. However, these types of plants are associated with high production costs and difficulties in controlling production during temporary variations in solar resource availability. In order to minimize these drawbacks, this study proposes the hybridization of CSP technology with direct biomass combustion, with the particularity of an innovative process scheme that does not correspond to traditional series or parallel configurations. This paper focuses on the techno-economic evaluation of this novel configuration in a small-scale power plant. To achieve this, both solar resource and biomass production, which are dependent on the selected location, were analyzed. Additionally, the plant was characterized from both technical and economic perspectives. The obtained results allowed for the characterization of the Levelized Cost of Energy (LCOE) based on various parameters such as the size of the solar field and biomass boilers, as well as limitations on biomass consumption.

Biomass power plants

Biomass power plants

Performance analysis of biomass direct combustion heating and centralized biogas supply system for rural districts in China

With the rapid urbanization of China, many farmers are living in buildings and districts far from natural gas pipelines and heating pipe networks. Besides electricity, they urgently need a cheaper energy source for heating and cooking. In this paper, a novel mode of biomass direct combustion heating and centralized biogas supply system was put forward, and corresponding theritical model was developed and verified with a practical operation system in Nan'an community of Wuwei City, China. The energy conservation and loss mechanism, energy economy, thermodynamic performance, and environmental benefits of the system are analyzed and explored on the basis of the system's year-round operating conditions and the community’s dynamic load characteristics. The results show that it is possible to meet the users' heat and biogas demands economically with biomass; the dynamic investment payback period(DIPP)is 4.23 years;the average annual primary energy saving rate(PESR)is 21.82 %; and the annual treatment of agricultural and livestock waste is 8198.57 t.The results of the study demonstrate the value and significance of biomass direct combustion heating and centralized biogas supply systems for achieving China's “Double Carbon” goal.

Bioenergy as an Alternative Energy Source: Progress and Development to Meet the Energy Mix in Indonesia

Government policies in Indonesia have been pushing in the past decade towards 100% electrification target by end of 2020. However, many of the new energy policies are reused from previous policies designed for different objectives causing overlap in policies between the central and local governments. Local distributed generation are not fully controlled by local stakeholders and community, and with the lack of long-term planning, continuous government incentives and support, they are bound to fail due to the lack of maintenance. The use of solid biomass for household has decreased significantly due to the government support for LPG stoves that overtaken other government projects supporting biomass. Small-scale biomass research is showing good progress towards the implementation of novel methods for biomass utilization. However, majority of the medium and large-scale projects are still relying on old technologies such as direct biomass combustion in boilers rather than the more environment friendly gasification technology. Another major biomass contribution to national energy mix is through liquid biofuels. This work summarizes the current and prospective energy mix in Indonesia and the main conventional and non-conventional energy sources and their environmental concerns. This work also gathers the latest local biomass research and biomass power plant projects.

Hybrid biomass and natural gas combined cycles: Energy analysis and comparison between different plant configurations

The research community has been investigating the integration of biomass into power plants to foster the energy transition to renewables and reduce the dependence on fossil fuels. The aim of the work is to evaluate the energy performance of different combined cycle configurations fueled by natural gas and lignocellulosic biomass, based on biomass gasification and direct combustion of biomass. In the former case, the plant is cofired (COF) with natural gas and syngas. In the latter, two plant configurations were compared: conventional Post-Combustion (PC) and Integrated Fired Recuperated Combined Cycles (BIFRCC), where post-combustion is used to increase the temperature of the air leaving the compressor. The capacity of the systems to integrate biomass was compared with conventional biomass-only plants. The influence of the biomass share has been studied on the main performance indicators: global and biomass efficiency; electrical power increase due to biomass addition; carbon dioxide emissions. An optimization was carried out to identify the most suitable plant configuration and the proper biomass fraction to achieve a trade-off between the need to maintain high global efficiency and high biomass integration. The BIFRCC system has proven to be the most appropriate, with a 35.3% biomass feed ratio and a 41.8% biomass efficiency, significantly higher than conventional steam plants (30% maximum efficiency).

Thermo-economic optimization of biomass-fired organic Rankine cycles combined heat and power system coupled CO2 capture with a rated power of 30 kW

Combining organic Rankine cycle (ORC) and biomass direct combustion to form a combined heating and power system (CHP) is a feasible technology to realize small biomass power generation. A small-scale biomass-fired ORC-CHP system with a rated power of 30 kW is proposed and the thermo-economic optimization under two operation strategies is discussed. The effects of key operating parameters on exergy efficiency and levelized energy cost (LEC) are analyzed. Meanwhile, a single-objective optimization for maximum exergy efficiency or minimum LEC is addressed, and a further thermo-economic optimization is examined. The Pareto-optimal solutions using three decision makings are yielded and compared. Research demonstrates that the exergy efficiency of model A increases with condensation temperature, while the exergy efficiency of model B first increases, reaches the peak, and then slightly decreases. The split ratio has a significant effect on model B. The Pareto-optimal solutions from TOPSIS decision making are selected because of its lowest deviation index. The Pareto optimal solution for models A and B in pairs of (exergy efficiency, LEC) are (19.69%, 0.2968) and (19.75%, 0.2975), respectively. Compared to model A, model B presents higher thermodynamic performance and slightly lower economic performance.

Comparative study on biomass treatment equipment based on dry anaerobic fermentation and direct combustion treatment

Biomass energy has great application potential, but direct combustion of biomass not only has low utilization rate, but also is easy to produce secondary pollution. In order to make better use of biomass, through the application of biomass fermentation equipment of dry anaerobic fermentation technology, this paper carries out simulated fermentation experiments, compares the results of direct combustion treatment, draws the conclusion that the technical and economic effect of fermentation treatment is more advantageous, and points out that the treatment mode of biomass treatment should be reasonably selected for efficient and convenient treatment in the future

Techno-economic analysis of 30MW biomass power plant modification for heating supply

Biomass combined heat and power (CHP) generation is the more efficient use of biomass compared the direct combustion power generation. The techno-economic analysis of 30 MW biomass direct combustion power set’s modification for heat supply is investigated in this work. Three schemes are employed to provide the district heating supply, including low vacuum condenser, steam extraction, and turbine bypass. The low vacuum condenser approach is the most promising based on the techno-economic analysis. The calculated outlet pressure of the steam turbine, the power generation capacity, the heating supply and the maximum heating area are 30KPa, 27MW, 143.58GJ/h, and 900,000 m2respectively. The expected annual income of biomass combined heat and power plants amounts up to 7,422,700 RMB.

Recent advances of hybrid solar - Biomass thermo-chemical conversion systems

Solar biomass hybridization is a promising energy technique for efficient utilization while mitigating the disadvantages associated with both biomass and solar energy source. In conventional concentrating solar power (CSP) systems, the contribution of solar energy is relatively low, merely supplementing the system with low/medium temperature air/steam. This paper aimed to emphasize the improvement of solar heat share, particularly in the topping cycle of the hybrid system. The solar aided processes, either directly generating superheated air/steam or direct gasification are thermodynamically favorable at very high temperatures, in excess of 800 °C. Unfortunately, this temperature is unattainable in conventional CSP systems using molten salt. Accordingly, the integration of solar power tower (SPT) with solid particle fluidized system in a beam down configuration has been proposed for the hybrid solar-biomass systems. Studies of such integration system presented challenges in terms of operating temperature, continuous supply/syngas production and scaling of reactor, particularly for circulating fluidized bed (CFB). The selection of solid particle and gas flow rate are among the governing parameters for high operating temperature and effective utilization of solar heat. The development of high temperature hybrid solar-biomass system is anticipated for higher solar-to-fuel conversion efficiencies, minimizing the direct combustion of biomass and reduce the emission of greenhouse gas (GHG) emissions.

Investigation of the flow and heat transfer performance for a water-cooling grate in a biomass boiler

ABSTRACT Biomass direct combustion power generation technology can effectively take the advantage of the biomass resources. Water-cooled reciprocating grate has become the research hotpot of biomass boilers for its advantages such as excellent performance and controllable cost. This paper mainly studies the flow and heat transfer performance of the water-cooled reciprocating grate, according to the different combustion state, the boiler can be divided into four sections: the moisture evaporation section, the volatile release section, the char combustion section and the cooling section. A porous model is used to simulate the biomass combustion process in different sections. Results indicate that the porous model can show more details about the temperature distribution of the grate, which is closer to the real situation. Compared to the traditional model, the relative deviations of main parameters against the heat transfer performance are less than 5%. With the increase of mass flow rate, the descend amplitude of the temperature decreases, but the ascend amplitude increases sharply, which would increase the operation cost. The least mass flow rate needed to keep the temperature rise between the inlet and outlet less than 5°C for the moisture evaporation section, the volatile release section, the char combustion section and cooling section are 0.46 kg·s−1, 0.55 kg·s−1, 4.60 kg·s−1, and 0.23 kg·s−1, respectively. For the moisture evaporation section, the volatile release section and the cooling section, the temperature of the grate and cooling water is low on the middle but high on the tail, while it is opposite for the char combustion section, due to the variation of combustion state and biomass thickness in different sections. Besides, it is found that the longitudinal vortices could pose great influence on the uniform distribution of cooling water. To optimize the cooling effect, it is important to reorganize the water channel and reduce the longitudinal vortices.

An overview of biofuel power generation on policies and finance environment, applied biofuels, device and performance

The prices of fossil fuels, the gap between energy supply and demand, energy security, environmental issues, and the reduction of greenhouse gas emissions commonly promote the development of biomass power generation in China. Compared to direct biomass combustion power generation and biogas power generation, liquid biofuel power generation has better application potential. Policies and finance environment of countries and organizations have promoted the extensive application of biofuel power generation in recent years, especially in China. Evaluation of internal combustion engine, gas turbine and fuel cell on the stationary power station and mobile generation shows that gas turbine is the main generator-set, the fuel cell is the fastest-growing and future generator-set, while the engine is the first choice in transport and low power generation field. As the second, third and fourth generation biofuels, biomethanol, bioethanol, biodiesel and others have been researched and widely used in power generation. In addition, power generation performance and emissions have been improved to some extent after biofuels supplying. For the future, combined heat and power (CHP) generation and integrated gasification combined cycle (IGCC) is imperative development trends of power generation for higher energy and exergy efficiency. CHP based on the various generating facilities will be the next choice and direction of energy use trends for transport.

Exergo-economic analysis and multi-objective multi-verse optimization of a solar/biomass-based trigeneration system using externally-fired gas turbine, organic Rankine cycle and absorption refrigeration cycle

• A solar/biomass-based trigeneration system has been proposed. • The system comprises an EFGT, an ORC, and a LiBr/H 2 O absorbtion refrigeration cycle. • The system is studied from the energy, exergy, and exergo-economic perspective. • Solar thermal improves the thermodynamic efficiency of the system by about 10%. • MOMVO outperforms MOPSO and NSGA-II in solving multi-objective optimization problem. In the present work, an innovative configuration is proposed based on solar pre-heating concept and biomass direct-combustion for combined production of electricity, hot water and cooling load. The studied system consists of an externally fired gas turbine, a trans-critical organic Rankine cycle, and a Li-Br/H 2 O absorption refrigeration cycle. The proposed system is thoroughly analyzed from the energy, exergy, and exergo-economic viewpoint. The results of the exergo-economic analysis demonstrate that the energy and exergy efficiencies of the reference case are 55.56% and 20.38% and the product cost rate is 26.4 $/h. Comparing the thermodynamic results to the literature, it is proved that the proposed system generates a considerably higher amount of power, heating, and cooling load which results in an improvement of energy efficiency by about 10%. In further, the main design parameters of each cycle are parametrically assessed to gain a comprehensive understanding of the system behavior. Finally, a new multi-objective optimization algorithm called multi-objective multi-verse optimizer (MOMVO) is employed to maximize exergy efficiency and minimize the product cost rate of the system. Compared to the base case, TOPSIS implementation revealed that the optimal final solution of the Pareto-frontier found by the MOMVO has about 9% higher second law efficiency while the product cost rate is decreased by around 6%. This result proved the better performance of the MOMVO compared to other conventional evolutionary-based multi-objective optimzation algorithms.

To decarbonize industry, we must decarbonize heat

Summary Industry is often termed “hard to decarbonize” because a vast, inhomogeneous array of processes comprise the sector. But developing new, decarbonized process heating technologies represents a single, broadly applicable pathway to eliminating a large portion of sectoral emissions—and approximately one-fifth of global CO2 emissions, overall. We begin this perspective with a brief review of the demand for and cost of industrial heat. Then, we highlight key challenges and R&D needs in developing zero-carbon industrial heating technologies. Technologies in four pathways are discussed: (1) zero-carbon fuels, (2) zero-carbon heat sources, (3) electrification of heat, and (4) better heat management. Finally, we identify cross-cutting challenges to the development and adoption of zero-carbon industrial heat technologies, the solution to any of which would constitute a significant breakthrough on the path to industrial decarbonization.

Risk analysis in terms of implementation of large scale cogeneration power plant

The introduction of large-scale technology carries a number of risks. This paper presents the risks associated with the introduction of a system for combined production of electricity and thermal energy (CHP) through direct combustion of biomass. It is envisaged that the residual amount of heat energy will be converted into electricity through the use of an ORC module. All possible risks have been identified based on the technology specifics, and the possible consequences of the risk have been indicated. A risk matrix has been prepared for both site and technology specifics in order to identify the type of risk. Based on the outputs, a proposal for reducing the risk has been made.