| 1. |
- Li, Hailong, 1976-, et al.
(författare)
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Performance of flue gas quench and its influence on biomass fueled CHP
- 2019
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Ingår i: Energy. - : Elsevier. - 0360-5442 .- 1873-6785. ; 180, s. 934-945
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Tidskriftsartikel (refereegranskat)abstract
- For biomass/waste fueled power plants, stricter regulations require a further reduction of the negative impacts on the environment caused by the release of pollutants and withdrawal of fresh water externally. Flue gas quench (FGQ) is playing an important role in biomass or waste fueled combined heat and power (CHP) plants, as it can link the flue gas (FG) cleaning, energy recovery and wastewater treatment. Enhancing water evaporation can benefit the concentrating of pollutant in the quench water; however, when FG condenser (FGC) is not in use, it results in a large consumption of fresh water. In order to deeply understand the operation of FGQ a mathematic model was developed and validated against the measurements. Based on simulation results key parameters affecting FGQ have been identified, such as the flow rate and temperature of recycling water and the moisture content of FG. A guideline about how to reduce the discharge of wastewater to the external and the withdrawal of external water can be proposed. The mathematic model was also implemented into an ASPEN Plus model about a CHP plant to assess the impacts of FGQ on CHP. Results show that when the FGC was running, increasing the flow rate and decreasing the temperature of recycling water can result in a lower total energy efficiency.
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| 2. |
- Bian, Xiaolei, et al.
(författare)
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A model for state-of-health estimation of lithium ion batteries based on charging profiles
- 2019
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Ingår i: Energy. - : Elsevier Ltd. - 0360-5442 .- 1873-6785. ; 177, s. 57-65
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Tidskriftsartikel (refereegranskat)abstract
- Using an equivalent circuit model to characterize the constant-current part of a charging/discharging profile, a model is developed to estimate the state-of-health of lithium ion batteries. The model is an incremental capacity analysis-based model, which applies a capacity model to define the dependence of the state of charge on the open circuit voltage as the battery ages. It can be learning-free, with the parameters subject to certain constraints, and is able to give efficient and reliable estimates of the state-of-health for various lithium ion batteries at any aging status. When applied to a fresh LiFePO 4 cell, the state-of-health estimated by this model (learning-unrequired or learning-required)shows a close correspondence to the available measured data, with an absolute difference of 0.31% or 0.12% at most, even for significant temperature fluctuation. In addition, NASA battery datasets are employed to demonstrate the versatility and applicability of the model to different chemistries and cell designs.
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| 3. |
- Bian, Xiaolei, et al.
(författare)
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An open circuit voltage-based model for state-of-health estimation of lithium-ion batteries : Model development and validation
- 2020
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Ingår i: Journal of Power Sources. - : Elsevier. - 0378-7753 .- 1873-2755. ; 448
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Tidskriftsartikel (refereegranskat)abstract
- An open circuit voltage-based model for state-of-health estimation of lithium-ion batteries is proposed and validated in this work. It describes the open circuit voltage as a function of the state-of-charge by a polynomial of high degree, with a lumped thermal model to account for the effect of temperature. When applied for practical use, the model requires a prior learning from the initial charging or discharging data for the sake of parameter identification, using e.g. a nonlinear least squares method, but it is undemanding to implement. The study shows that the model is able to estimate the state-of-health of a LiFePO4 cell cycled under conditions where the temperature has fluctuated significantly with a relative error less than 0.45% at most. A short part of a constant current profile is enough for state-of-health estimation, and the effect of size and location of voltage window on the model's accuracy is also studied. In particular, the reason of accuracy change with different voltage windows is explained by incremental capacity analysis. Additionally, the versatility and flexibility of the model to different chemistries and cell designs are demonstrated.
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| 4. |
- Bian, Xiaolei, 1990-
(författare)
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State Estimation of Lithium-ion Batteries
- 2021
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- To guarantee the safety operation, the key states of lithium-ion battery, e.g., the state of charge and the state of health, must be estimated and monitored accurately. This thesis is mainly to develop models and algorithms to accurately and robustly estimate the key battery states, based on the available measurements i.e., current and voltage. All the work is based on four published papers and can be divided into three parts.The first part of this work presents a two-step parameter optimization method for online state of charge estimation of lithium-ion battery. The particle swarm optimization is exploited for model parametrization and extended Kalman filter tuning. Within this particle swarm optimization-based framework, the searching boundary is derived by scrutinizing the error transition property of the test system, which can narrow the searching region and increase the computational efficiency. In general, the proposed method can well exploit the potential of model-based estimators, leading to a robust model compatibility and optimized performance.In the second part of this thesis, two novel models are developed to estimate the state of health of lithium-ion battery. The first one is an open circuit voltage-based model, which describes the open circuit voltage as a function of the state of charge by a polynomial, with a lumped thermal model to account for the effect of temperature. It requires a prior learning from the initial constant-current profile. The second model is an incremental capacity analysis-based model, which defines the dependence of the state of charge on the open circuit voltage using a capacity model. It can be learning-free, with the parameters subject to certain constraints. Both models use an equivalent circuit model to characterize the constant-current profiles and a nonlinear least squares method to identify the involving parameters. These two models are validated by aging experiments, and the results show that both can give accurate state-of-health estimation.The third part of the thesis introduces a fusion-type state-of-health estimator by combining the model-based profile reconstruction and the incremental capacity analysis-based state estimation. The above-mentioned open circuit voltage-based model is employed here to mitigate the noise-induced unfavorable numerical conditions and to modify the incremental capacity curves. Leveraging the modified incremental capacity curves, a set of feature-of-interests are extracted and evaluated, and several cautiously selected ones are used to estimate the state of health of lithium-ion battery. Long-term cycling tests on different lithium-ion batteries are used for validation. This fusion-type method has comparable accuracy and better robustness, compared with the model-based methods. Moreover, the proposed estimator has a good generality to different batteries and also promises an excellent robustness against cell inconsistency, noise corruption, temperature variety, and profile partialness.
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| 5. |
- Galanopoulos, Christos, et al.
(författare)
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Impacts of acidic gas components on combustion of contaminated biomass fuels
- 2018
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Ingår i: Biomass and Bioenergy. - : Elsevier. - 0961-9534 .- 1873-2909. ; 111, s. 263-277
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Tidskriftsartikel (refereegranskat)abstract
- The formation of high concentrations of acid gases; in combustion with large variations in fuel qualities, represents a major challenge for energy production from contaminated biomass fuels. This paper provides a comprehensive evaluation of the effects of acid gas formation and retention in the combustion of recycled wood fuels. A model has been developed based on the chemical reactions involved and empirical correlations from plant monitoring and testing. The model has been used to study the behaviour of acidic gas components in critical stages of a bubbling fluidised bed boiler process. Results indicate that the variation in type of fuel contamination is the most important issue to deal with in the combustion of recycled wood fuels. Peaks in the flue gas chlorine concentrations cannot be suppressed easily by conventional flue gas cleaning measures. Upon applying ammonium sulphate dosing for the protection of chlorine induced corrosions, it is sometimes difficult to maintain the required S/Cl ratio when large variations of fuel chlorine occur. Moreover, a high level of chlorine in the fuel can also indirectly affect the emission control of sulphur dioxide because it would require an increased level of ammonium sulphate decomposition, which results in a high level of SO2 in flue gas. The study also shows a beneficial effect of the recirculation of quench water from the flue gas condenser to the boiler. It offers opportunities for the optimisation of flue gas cleaning and flue gas condensation, for improving the efficiencies of water and wastewater treatment, as well as for emission reduction with a sustainable way.
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| 6. |
- Larsson, Magnus, et al.
(författare)
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Characterisation of stormwater in biomass-fired combined heat and power plants : Impact of biomass fuel storage
- 2016
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Ingår i: Applied Energy. - : Elsevier. - 0306-2619 .- 1872-9118. ; 170, s. 116-129
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Tidskriftsartikel (refereegranskat)abstract
- Characteristics of stormwater in industrial areas are evaluated, specifically based on a biomass-fired combined heat and power (CHP) plant with on-site biomass fuel storage. An evaluation method is developed to combine general methodology applied for stormwater characterisation with the on-site features of the biomass-fired CHP plant. Investigations were carried out through on-site monitoring and laboratory experiments with the defined methodology. Recycled wood chips as biomass fuel currently used in Swedish biomass-fired CHP plants have been used as an example for this study. The impacts of outdoor biomass fuel storage have been analysed for both runoff water quantity and quality. The results indicate that the properties of stored biomass fuels will significantly affect the runoff quantity by its water absorption capability. The overall runoff quality is highly depended on precipitation intensity and the runoff volume from the biomass storage piles, which is influenced by the water retention capacity and leaching ability of biomass fuels. The practical data and information presented in this paper can be used to understand the principal issues and the most important factors for internal control of contamination sources in order to achieve sustainable Energy-Water systems for bioenergy conversion in biomass-fired CHP plants.
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| 7. |
- Li, X., et al.
(författare)
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Prognostic health condition for lithium battery using the partial incremental capacity and Gaussian process regression
- 2019
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Ingår i: Journal of Power Sources. - : Elsevier. - 0378-7753 .- 1873-2755. ; 421, s. 56-67
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Tidskriftsartikel (refereegranskat)abstract
- Precisely battery state of health estimation and remaining useful lifetime prediction are crucial factors in ensuring the reliability and safety for system operation. This paper thus focuses on the short-term battery state of health estimation and long-term battery remaining useful lifetime prediction. A novel hybrid method by fusion of partial incremental capacity and Gaussian process regression is proposed and dual Gaussian process regression models are employed to forecast battery health conditions. First, the initial incremental capacity curves are filtered by using the advanced signal process technology. Second, the important health feature variables are extracted from partial incremental capacity curves using correlation analysis method. Third, the Gaussian process regression is applied to model the short-term battery SOH estimation using the feature variables. Forth, an autoregressive long-term battery remaining useful lifetime model is established using the results of battery SOH values and previous output. The predictive capability and effectiveness of two models are demonstrated by four battery datasets under different cycling test conditions. Otherwise, the robustness of the two models is verified using four datasets with different health levels. The experimental results show that the proposed method can provide accurate battery state of health estimation and remaining useful lifetime.
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| 8. |
- Wang, Bin, et al.
(författare)
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Modelling the Quench Tower in Flue Gas Cleaning of a Waste Fueled Power Plant
- 2018
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Ingår i: JOINT INTERNATIONAL CONFERENCE ON ENERGY, ECOLOGY AND ENVIRONMENT ICEEE 2018 AND ELECTRIC AND INTELLIGENT VEHICLES ICEIV 2018. - : DEStech Publishing Inc. - 9781605955902
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Konferensbidrag (refereegranskat)abstract
- To control the emission of pollutants in the flue gas, a separated flue gas quench was added after flue gas desulfurization and before flue gas condensation. A mathematic model was developed to simulate the heat and mass transfer in the flue gas quench. The model was validated through the comparison with measured data. Based on this model, the impacts of inlet flue gas condition and injected recycling water flow rate on the water consumption of the quench and the temperature of exit flue gas (FG) were studied. The results show that the temperature of exit FG and water consumption increased with the increase of flow rate and moisture content of FG. The temperature of exit FG increased and the water consumption decreased with the increase of droplet water diameter. The temperature of exit FG decreased and the water consumption increased with the increase of water flow rate. In order to cooled and humidified the flue gas sufficiently, the droplet diameter should be limited to 1.2 mm and the water to FG flow rate ratio (L/G) higher than 2.
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| 9. |
- Yan, Jinying, et al.
(författare)
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Contamination of heavy metals and metalloids in biomass and waste fuels : Comparative characterisation and trend estimation
- 2020
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Ingår i: Science of the Total Environment. - : Elsevier. - 0048-9697 .- 1879-1026. ; 700, s. 1-19
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Tidskriftsartikel (refereegranskat)abstract
- The use of contaminated biomass and waste fuels is essential for waste management, waste to energy (WtE) and mitigating carbon emissions. The contamination of heavy metals and metalloids is specially concerned by environmental regulation and waste to energy processes. In this study, comparative characterisation is performed for three typical contaminated biomass and waste fuels. i.e. recycled woods, combustible municipal solid waste, and industrial and commercial wastes. The contamination characteristics are further analysed using statistical methods (e.g. significance, correlation, profile, and principal component analyses) to identify specific contamination features, relations among the contaminants and potential contamination sources. Contamination trend is estimated based on the continuously monitoring fuel qualities, the driving forces for regulating and reduction of the contaminations, and potential changes in major contamination sources. The comparative characterisation combined with statistical analyses provides a better way to understand the contamination mechanisms. The approach can also relate the fuel contamination with the contamination sources and their changes for trend estimation. Generally, the toxic heavy metals and metalloids are expected to be significantly reduced due to stricter regulations, but there is no general trend for the reduction of other metals and metalloids because of the complicated changes in contamination sources and waste recycling streams in the near future. (C) 2019 Elsevier B.V. All rights reserved.
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| 10. |
- Yan, Jinying
(författare)
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Major leaching processes of combustion residues : characterisation, modelling and experimental investigation
- 1998
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Characterising leaching behaviour provides ample evidence toidentify the majorleaching processes of combustion residues.Neutralisation and chemical weatheringgovern the leachingreactions and control the release of major, minor and traceelementsfrom combustion residues, and are thus considered to bethe major leaching processes.Several geochemical models are used to describe theneutralisation and chemicalweathering processes based onleaching kinetics and the features of leaching systems.Areaction path model is used to evaluate the neutralisingprocesses in a batch system. Theneutralising processes in aflow-through system are assessed using an equilibriumreactivetransport model which accounts for most neutralising reactionsunder the experimental conditions. A kineticreactive transportmodel taking full kineticconsideration for heterogeneousreactions is used to simulate long-term chemicalweathering.According to experimental investigations and geochemicalsimulations, the leachingkinetics of buffering materials arekey issues for the understanding of the neutralisingprocesses.The acid neutralising capacity (ANC) at different pH levelsdepends mainly onthe mineralogy of the combustion residues. Thetime-dependent and pH-dependent neutralising behaviours aredetermined by the matrix phases of a solid waste. Incombustionresidues, the dissolution of glass phases is expected to playan important rolein a long-term neutralising process. Theneutralising process in a flow system issignificantly differentfrom that in a batch system. In general, the informationobtainedfrom batch experiments cannot directly to be used in aflow system. The neutralising ability of a combustion residuemay be strongly affected by solute transport and carbonationreactions in a natural leaching environment.The chemical weathering mainly involves the matrix ofcombustion residues consistingmostly of glass phases. Thedissolution kinetics of waste glass and other possibleprocesses involved in the chemical weathering have beeninvestigated and incorporatedinto a kinetic reactive transportmodel. Most important processes in the chemical weathering canbe simulated simultaneously using this model. The results showthat thereis a complicated relationship between the factorscontrolling the long-term chemicalweathering. The dissolutionof the waste matrix is strongly affected by itsdissolutionkinetics and weathering environment. Theenvironmental impact of the glass dissolutioncannot beneglected. Although the glass dissolution provides considerablebufferingcapacity in long-term weathering, the carbonate isusually a dominant buffering mineralin actual weatheringprocesses. The transformation of carbonate should be consideredasan important process in the chemical weathering. Theformation of secondary minerals,clay-like minerals (e.g.illite) and amorphous silica, may considerably alter themineralogy of the waste, and thus change the leachingbehaviours of the combustion residue duringlong-term chemicalweathering.Keywords:Leaching; neutralisation; chemical weathering;solid waste; combustionresidues; long term; geochemicalmodelling; reaction path model; reactive transportmodel
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| 11. |
- Zhang, Xiaojing, et al.
(författare)
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Investigation of thermal integration between biogas production and upgrading
- 2015
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Ingår i: Energy Conversion and Management. - : Elsevier BV. - 0196-8904 .- 1879-2227. ; 102, s. 131-139
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Tidskriftsartikel (refereegranskat)abstract
- Thermal integration of anaerobic digestion (AD) biogas production with amine-based chemical absorption biogas upgrading has been studied to improve the overall efficiency of the intergraded system. The thermal characteristics have been investigated for industrial AD raw biogas production and amine-based chemical absorption biogas upgrading. The investigation provides a basic understanding for the possibilities of energy saving through thermal integration. The thermal integration is carried out through well-defined cases based on the thermal characteristics of the biogas production and the biogas upgrading. The following factors are taken into account in the case study: thermal conditions of sub-systems, material and energy balances, cost issues and main benefits. The potential of heat recovery has been evaluated to utilise the waste heat from amine-based upgrading process for the use in the AD biogas production. The results show that the thermal integration has positive effects on improving the overall energy efficiency of the integrated biogas plant. Cost analysis shows that the thermal integration is economically feasible.
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| 12. |
- Zheng, Ligang, et al.
(författare)
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Coal utilization for power and heat generation
- 2023. - 2nd
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Ingår i: The Coal Handbook: Volume 2: Towards Cleaner Coal Utilization. - : Elsevier BV. ; , s. 457-492
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- This chapter critically reviews thermal coal utilization for electricity generation and heat production. It outlines the share of coal in today’s energy mix and its future role in a carbon constraint world. Major coal-fired power generation technologies are discussed in terms of history and current developments. Emission control technologies in thermal coal utilization are summarized with focus on the abatement of climate impacts and further improvement of other environment performance. Main technologies for CO2 capture and co-combustion of biomass are examined as well.
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