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  • 1.
    Han, Song
    et al.
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Starfelt, Fredrik
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Daianova, Lilia
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Yan, Jinyue
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Influence of drying process on the biomass-based polygeneration system of bioethanol, power and heat2012In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 90, no 1/SI, p. 32-37Article in journal (Refereed)
    Abstract [en]

    One of the by-products from bioethanol production using woody materials is lignin solids, which can be utilized as feedstock for combined heat and power (CHP) production. In this paper, the influence of integrating a drying process into a biomass-based polygeneration system is studied, where the exhaust flue gas is used to dry the lignin solids instead of direct condensation in the flue gas condenser (FGC). The evaporated water vapor from the lignin solids is mixed with the drying medium for consequent condensation. Thus, the exhaust flue gas after the drying still has enough humidity to produce roughly the same amount of condensation heat as direct condensation in the existing configuration. The influence of a drying process and how it interacts with the FGC in CHP production as a part of the  polygeneration system is analyzed and evaluated. If a drying process is integrated with the polygeneration system, overall energyefficiency is only increased by 3.1% for CHP plant, though the power output can be increased by 5.5% compared with the simulated system using only FGC.

  • 2. Leduc, Sylvain
    et al.
    Starfelt, Fredrik
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Dotzauer, Erik
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Kinderman, Georg
    McCallum, Ian
    Obersteiner, Mickael
    Lundgren, Joachim
    Optimal location of lignocellulosic ethanol refineries with polygeneration in Sweden2010In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 35, no 6, p. 2709-2716Article in journal (Refereed)
    Abstract [en]

    The integration of ethanol production with combined heat and power plants is considered in this paper. An energy balance process model has been used to generate data for the production of ethanol, electricity, heat and biogas. The geographical position of such plants becomes of importance when using local biomass and delivering transportation fuel and heat. An optimization model has thus been used to determine the optimal locations for such plants in Sweden. The entire energy supply and demand chain from biomass outtake to gas stations filling is included in the optimization. Input parameters have been studied for their influence on both the final ethanol cost and the optimal locations of the plants. The results show that the biomass cost, biomass availability and district heating price are crucial for the positioning of the plant and the ethanol to be competitive against imported ethanol. The optimal location to set up polygeneration plants is demonstrated to be in areas where the biomass cost is competitive and in the vicinity of small to medium size cities. Carbon tax does not influence the ethanol cost, but solicits the production of ethanol in Sweden, and changes thus the geography of the plant locations.

  • 3.
    Lindberg, Carl-Fredrik
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center. ABB Corp Res, Västerås, Sweden..
    Tan, SieTing
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center. Univ Teknol Malaysia, Johor, Malaysia.
    Yan, JinYue
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Starfelt, Fredrik
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center. MälarEnergi, Västerås, Sweden.
    Key performance indicators improve industrial performance2015In: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 75, p. 1785-1790Article in journal (Refereed)
    Abstract [en]

    Key Performance Indicators (KPIs) are important for monitoring the performance in the industry. They can be used to identify poor performance and the improvement potential. KPIs can be defined for individual equipment, sub-processes, and whole plants. Different types of performances can be measured by KPIs, for example energy, raw-material, control & operation, maintenance, etc. Benchmarking KPIs with KPIs from similar equipment and plants is one method of identifying poor performing areas and estimating improvement potential. Actions for performance improvements can then be developed, prioritized and implemented based on the KPIs and the benchmarking results. An alternative to benchmarking, which is described in this paper, is to identify the process signals that are strongest correlated with the KPI and then change these process signals in the direction that improves the KPI. This method has been applied to data from a combined heat and power plant and a suggestion are given on how to improve boiler efficiency. 

  • 4.
    Ma, Z.
    et al.
    Beijing University of Posts and Telecommunications, Beijing, China.
    Li, Hailong
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Sun, Q.
    Shandong University, Jinan, China .
    Wang, C.
    Tongji University, Shanghai, China.
    Yan, A.
    Tianjin Institute of Urban Construction, Tianjin, China .
    Starfelt, Fredrik
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Statistical analysis of energy consumption patterns on the heat demand of buildings in district heating systems2014In: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 85, p. 664-672Article in journal (Refereed)
    Abstract [en]

    Precise prediction of heat demand is crucial for optimising district heating (DH) systems. Energy consumption patterns (ECPs) represent a key parameter in developing a good mathematical model to predict heat demand. This study quantitatively investigated the impacts of ECPs on heat consumption. Two key factors, namely, time and type of buildings, were used to reflect various ECPs in DH systems, and a Gaussian mixture model (GMM) was developed to examine their impacts on heat consumption. The model was trained and validated using the measured data from a real DH system. Results show that the factor of time does not represent a good reflection of ECP. In contrast, categorising buildings according to their function is an effective way to reflect ECPs. Based on the defined building types, i.e., commercial, apartment and office, the average absolute deviation of the predicted heat load was about 4-8%.

  • 5.
    Paz, Ana
    et al.
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Starfelt, Fredrik
    Dahlquist, Erik
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Thorin, Eva
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Yan, Jinyue
    Mälardalen University, School of Sustainable Development of Society and Technology.
    How to achieve a fossil fuel free Malardalen region2007In: Conference proceedings of 3rd IGEC-2007,, 2007Conference paper (Refereed)
  • 6.
    Starfelt, Fredrik
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    From Combined Heat and Power to Polygeneration2015Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    In order to reach targets on reducing greenhouse gas emissions from fossil resources it is necessary to reduce energy losses in production processes. In polygeneration, several processes are combined to complement each other to avoid sub-optimization of the standalone processes. This thesis addresses polygeneration with focus on Combined Heat and Power (CHP) production integrated with other processes. Biomass-fired CHP plants are commonly dimensioned to have surplus heat production capacity during periods with lower heat demand. At the same time, production of biomass based vehicle fuels and fuel upgrading are heat demanding processes. The opportunity to combine CHP with ethanol production from lignocellulosic feedstock and torrefaction with the aim of replacing fossil fuels are used as cases during the evaluation of polygeneration. Simulation models are used to investigate the performance of CHP integrated with production of ethanol and torrefaction. Measured data from commercial CHP plants have been used to reflect the operation boundaries. The findings show that polygeneration can compete with stand-alone production in both energy and economic performance. Polygeneration offers a wider operating range where reduced minimum load gives increased annual operating time. Therefore, under limited heat demand more renewable electricity production is possible due to increased operating hours and steam extraction from the turbine during part-load operation. Resource availability and fluctuations in fuel price have the largest impact on the profit of polygeneration. Other aspects that have substantial effects on the economy in polygeneration are the electricity spot price and subsidies. Furthermore, it has been proven that the yield of each product in a multiproduct process plant, the size of the plant and the heat demand have a large impact on the economy. Polygeneration turns by-products into buy-products.

  • 7.
    Starfelt, Fredrik
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Improving the performance of combined heat and power plants through integration with cellulosic ethanol production2011Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Today’s biomass-fired combined heat and power (CHP) plants have surplus heat production capacity during warmer times of the year. In order to allow them to increase their electricity production, it is essential to find a use for the surplus heat.

    Additionally, the transport sector is struggling with high fuel prices and the contribution of CO2 emissions to global warming. A promising way of reducing the negative effects caused by combustion of fossil fuels in the transport sector is to mix ethanol with gasoline, or to use pure ethanol in modified engines. Ethanol is produced by fermentation at low temperatures and the production process could be integrated with CHP plants.

    The first generation of ethanol production as fuel has recently been criticized for competing with food crops and for its production chain being a larger polluter than was first thought. The second generation of ethanol production from lignocellulosic materials offers very promising results, but this process has several steps that are energy demanding.

    This thesis presents the findings of research on the configuration of a CHP plant with an integrated second generation ethanol production process. It also presents the operational economics and optimal locations for such plants in Sweden. Two case studies were performed to compare different feedstocks for ethanol production.

    The results show that when electricity prices are high, CHP plants benefit from heat consumption. Even with low yields in an ethanol production process, the integrated plant can be profitable. The plant must be located where there is sufficient heat demand. A cellulosic ethanol production process can work as a heat sink with profitable outcomes even with the current state of development of cellulosic ethanol technology.

  • 8.
    Starfelt, Fredrik
    et al.
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Daianova, Lilia
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Yan, Jinuye
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Thorin, Eva
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Dotzauer, Erik
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Increased renewable electricity production in combined heat and power plants by introducing ethanol production2009Conference paper (Refereed)
    Abstract [en]

    The development towards high energy efficiency and low environmental impact by humaninteractions, has led to a change in many levels of society. Due to the introduction of penalties oncarbon dioxide emissions and other economic instruments, the energy industry is striving towardsenergy efficiency improvement and climate mitigation by switching from fossil to renewablefuels. Biomass-based combined heat and power (CHP) plants connected to district heatingnetworks have a need to find uses for excess heat to produce electricity during summer when theheat demand is low. On the other hand, the transport sector is contributing substantially to theincreased CO2 emissions, which have to be reduced. One promising alternative to address the twochallenging issues is the integration of vehicle fuel production with biomass based CHP plants. Inthis paper, the configuration and operation profits in terms of electricity, heat and ethanol fuelfrom cellulosic biomass are presented. A case study of a commercial small-scale CHP plant hasbeen carried out using simulation and modeling tools. The results clearly show that electricityproduction can be increased when CHP production is integrated with cellulosic ethanolproduction. The findings presented also show that the economical benefits of the energy systemcan be realized with near-term commercially available technology

  • 9.
    Starfelt, Fredrik
    et al.
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Daianova, Lilia
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Yan, Jinyue
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Thorin, Eva
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Dotzauer, Erik
    Mälardalen University, School of Sustainable Development of Society and Technology.
    The impact of lignocellulosic ethanol yields in polygeneration with district heating: A case study2012In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 92, p. 791-799Article in journal (Refereed)
    Abstract [en]

    The development towards high energy efficiency and low environmental impact from human interactions

    has led to changes at many levels of society. As a result of the introduction of penalties on carbon

    dioxide emissions and other economic instruments, the energy industry is striving to improve energy

    efficiency and climate mitigation by switching from fossil fuels to renewable fuels. Biomass-based combined

    heat and power (CHP) plants connected to district heating networks have a need to find uses for the

    excess heat they produce in summer when the heat demand is low. On the other hand, the transport sector

    makes a substantial contribution to the increasing CO

    2

    emissions, which have to be reduced. One

    promising alternative to address these challenging issues is the integration of vehicle fuel production

    with biomass-based CHP plants. This paper presents the configuration and operating profits in terms

    of electricity, heat and ethanol fuel from cellulosic biomass. A case study of a commercial small scale

    CHP plant was conducted using simulation and modeling tools. The results clearly show that electricity

    production can be increased when CHP production is integrated with cellulosic ethanol production. The

    findings also show that the economic benefits of the energy system can be realized with near-term commercially

    available technology, and that the benefits do not rely solely on ethanol yields.

  • 10.
    Starfelt, Fredrik
    et al.
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Thorin, Eva
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Dotzauer, Erik
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Yan, Jinyue
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Performance evaluation of adding ethanol production into an existing combined heat and power plant2010In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 101, no 2, p. 613-618Article in journal (Refereed)
    Abstract [en]

    In this paper, the configuration and performance of a polygeneration system are studied by modelling the integration of a lignocellulosic wood-to-ethanol process with an existing combined heat and power (CHP) plant. Data from actual plants are applied to validate the simulation models. The integrated polygeneration system reaches a total efficiency of 50%, meeting the heating load in the district heating system. Excess heat from the ethanol production plant supplies 7.9MWto the district heating system, accounting for 17.5% of the heat supply at full heating load. The simulation results show that the production of ethanol from woody biomass is more efficient when integrated with a CHP plant compared to a stand-alone production plant. The total biomass consumption is reduced by 13.9% while producing the same amounts of heat, electricity and ethanol fuel as in the stand-alone configurations. The results showed that another feature of the integrated polygeneration system is the longer annual operating period compared to existing cogeneration. Thus, the renewable electricity production is increased by 2.7% per year.

  • 11.
    Starfelt, Fredrik
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Tomas Aparicio, Elena
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Li, Hailong
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Dotzauer, Erik
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Integration of torrefaction in CHP plants - A case study2015In: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 90, p. 427-435Article in journal (Refereed)
    Abstract [en]

    Torrefied biomass shows characteristics that resemble those of coal. Therefore, torrefied biomass can be co-combusted with coal in existing coal mills and burners. This paper presents simulation results of a case study where a torrefaction reactor was integrated in an existing combined heat and power plant and sized to replace 25%, 50%, 75% or 100% of the fossil coal in one of the boilers. The simulations show that a torrefaction reactor can be integrated with existing plants without compromising heat or electricity production. Economic and sensitivity analysis show that the additional cost for integrating a torrefaction reactor is low which means that with an emission allowance cost of 37 €/ton CO2, the proposed integrated system can be profitable and use 100% renewable fuels. The development of subsidies will affect the process economy. The determinant parameters are electricity and fuel prices.

  • 12.
    Starfelt, Fredrik
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Tomas Aparicio, Elena
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Thorin, Eva
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Ericson, V.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Simultaneous dynamic and quasi-steady state simulations to optimize combined heat and power plant operation2012Conference paper (Refereed)
  • 13.
    Starfelt, Fredrik
    et al.
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Yan, J.
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Case study of energy systems with gas turbine cogeneration technology for an eco-industrial park2008In: International journal of energy research (Print), ISSN 0363-907X, E-ISSN 1099-114X, Vol. 32, no 12, p. 1128-1135Article in journal (Refereed)
    Abstract [en]

    Eco-industrial parks (EIP) are clusters of industry corporations that collaborate with reusing waste and energy-efficient use of resources with no or minor impact on the environment. This paper presents a case study that examines the feasibility of using gas turbine technology in one industrial park, located in the Dongguan city of the Guangdong province in China. A model of a gas turbine-based combined heat and power (CHP) plant with a heat recovery steam generator for absorption cooling was developed and simulated. A steam-injected gas turbine has been selected in the system to increase electricity production and to generate steam. The study includes performance analysis of the cogeneration plant in terms of thermal efficiency, cost estimation, and greenhouse gas emission. The gas turbine-based cogeneration system has been compared with a baseline reference case that is defined as if all the energy to the industrial park is supplied from the local electricity grid. The results show that the gas turbine-based cogeneration system can reach a total efficiency of 58% and reduce CO2 emissions with 12 700 tons per year. A sensitivity analysis on the costs of the system has also been made based on fuel costs and the interest rate, which shows that the investigated system is economically profitable at natural gas prices below 4.4 RMB m-3 with fixed electricity prices and at electricity prices above 736 RMB MWh-1 with fixed natural gas prices. The sensitivity analysis based on the interest rate showed that the proposed system is economically feasible with interest rates up to 16%.

  • 14.
    Starfelt, Fredrik
    et al.
    Mälardalen University, Department of Public Technology. Process and Resource Optimization.
    Yan, Jinyue
    Mälardalen University, Department of Public Technology. Royal Institute of Technology, Stockholm, Sweden.
    Case Study of Energy Systems with Gas Turbine Cogeneration Technology for an Eco-Industrial Park2007In: 3rd International Green Energy Conference: Proceedings of IGEC-III, 2007, 2007, p. 509-515Conference paper (Refereed)
    Abstract [en]

    Eco-industrial parks (EIP) are clusters of industry corporations that collaborate with reusing waste and energyefficient use of resources with no or minor impact on the environment. This paper presents a case study that examines the feasibility of using gas turbine technology in one industrial park, located in Dongguan city of Guangdong province in China.

    A model of a gas turbine based combined heat and power (CHP) plant with a heat recovery steam generator (HRSG) for absorption cooling was developed and simulated. A steam-injected gas turbine (STIG) has been selected in the system to increase electricity production while generating steam. The study includes performance analysis of the cogeneration plant in terms of thermal efficiency, cost estimation, and greenhouse gas emission. The gas turbine based cogeneration system has been compared to a baseline reference case that is defined as if all energy to the industrial park is supplied from the local electricity grid. The results show that the gas turbine based cogeneration system can reach a thermal efficiency of 58 % and reduce the CO2 emissions with 12,700 tons per year. A sensitivity analysis on the costs of the system has also been made based on fuel costs and interest rate which shows that the investigated system is economically profitable at natural gas prices below 4.4

    yuan/m³ with fixed electricity prices and at electricity prices above 736 yuan/kWh with fixed natural gas prices. The sensitivity analysis based on interest rate showed that the proposed system is economically feasible with interest rates up to 16 %.

  • 15.
    Tomas Aparicio, Elena
    et al.
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Li, Hailong
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Starfelt, Fredrik
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Dahlquist, Erik
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Dynamic Simulation of Torrefaction2012Conference paper (Refereed)
1 - 15 of 15
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