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  • 151.
    Thorin, Eva
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Olsson, Jesper
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Schwede, Sebastian
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Nehrenheim, Emma
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Co-digestion of sewage sludge and microalgae: Biogas production investigations2018Inngår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 227, s. 64-72Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In municipal wastewater treatment plants (WWTPs), algae could be utilised for cleaning the water and, at thesame time, produce a biomass that can be used for energy. Through anaerobic digestion, microalgae can contributeto biogas production when co-digested with sewage sludge. In this paper, previous published results onthe co-digestion of sewage sludge and microalgae are summarised and reviewed, and any remaining knowledgegaps are identified. The batch tests currently documented in literature mostly concern digestion under mesophilicconditions, and studies investigating thermophilic conditions are less common. The average biochemicalmethane potential (BMP) for 29 different mixtures co-digested under mesophilic conditions is 317 ± 101 N cm3CH4 gVS−1 while the result for 12 different mixtures investigated under thermophilic conditions is a BMP of318 ± 60 N cm3 CH4 gVS−1. An evaluation of the heat required for increasing the temperature from mesophilicto thermophilic conditions shows that increased methane production under thermophilic conditions can beenough to create a positive energy balance. For a full-scale WWTP, using thermophilic digestion on sludge, or acombination of sludge and microalgae could therefore be of interest. This is dependent on the demands onsanitation of the sludge and the possibilities for heat recovery.Most of the mesophilic investigations indicate a synergetic effect for co-digestion, with enhancements of up toalmost 70%. However, the results are uncertain since the standard deviations for some of the BMP tests are in thesame order of magnitude as the identified enhancement. Neither of the presented publications provide an understandingof the basic mechanisms that led to higher or lower BMP when microalgae were mixed with wastewatersludge. We, therefore, call for care to be taken when assuming any effects related to the specification ofsubstrates. Microalgae and wastewater sludge have several similarities, and the specific results of BMP in themixtures relate more to the specifics of the respective materials than the materials themselves.Investigations into semi-continuous processes of co-digestion of microalgae and sludge are scarce. The yieldsfor three co-digestion studies show high variation, with an average of 293 ± 112 N cm3 gVSin−1. The availableresults show strong potential for co-digestion of sewage sludge and microalgae. Further investigations are requiredto identify optimal conditions for biogas production, and analysis of microalgae implementation onwastewater treatment at a system level is also needed to identify the total mass balance of substrate and nutrientrecovery.

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  • 152.
    Thorin, Eva
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Sandberg, Jan
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. KTH, Sweden.
    Combined Heat and Power2015Inngår i: Handbook of Clean Energy Systems, John Wiley & Sons, 2015Kapittel i bok, del av antologi (Fagfellevurdert)
    Fulltekst (pdf)
    fulltext
  • 153.
    Thorin, Eva
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Schwede, Sebastian
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Lindmark, Johan
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Ahrens, Torsten
    Ostfalia University of Applied Science, Wolfenbüttel, Germany.
    DRY DIGESTION PILOT TESTS USING RESIDUAL MUNICIPAL WASTE AS SUBSTRATE2015Inngår i: Sardinia 2015 / [ed] Raffaello Cossu et al, Padova: CISA publisher , 2015Konferansepaper (Fagfellevurdert)
    Abstract [en]

    A pilot plug-flow dry digestion process was tested for production of biogas from the fine fraction of the residual municipal solid waste after source sorting of the organic fraction of the waste. The residual waste is complex, containing a mix of hard and soft plastic, paper, metal, glass, and a varying amount of organic material. The utilization as a substrate for biogas production is therefore challenging. The purpose of the pilot tests was to determine if it is technically feasible to produce biogas from this waste. The plant was operated under thermophilic conditions for almost three months. In parallel also a garage fermentation batch pilot plant was tested with the same substrate. The results from the tests are promising concerning the biogas production even if there are indications that the process in the plug-flow reactor was operated in so called inhibited steady state at the higher loading rates.

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  • 154.
    Törnwall, Elin
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Pettersson, Hanna
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Thorin, Eva
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Schwede, Sebastian
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Post-treatment of biogas digestate – An evaluation of ammonium recovery, energy use and sanitation2017Inngår i: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 142, s. 957-963Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The utilization of digestate from anaerobic digestion (AD) processes offers the possibility to recycle nutrient from organic wastematerials back to the food chain. However, digestates are characterized by a high water content resulting in high storagecapacities and transportation costs. Various organic wastes such as organic municipal solid waste (oMSW) require sanitation withat least one hour hydraulic retention time (HRT) at 70°C to inactivate pathogens for the safe release of the material.Consequently, the sanitation process is one of the largest energy consumers in the whole AD process chain. In this study, a posttreatmentof the biogas digestate was evaluated regarding the potential for energy savings and nutrient recovery via nitrogenstripping in comparison to the conventional pre-sanitation of the organic waste. With increasing HRT (one to three hours) andaeration flow (0.0-5.3 L air per L digestate and minute) more condensate and ammonia was removed from the digestate. The totalammonia removal from the digestate after one and three hours with the highest aeration flow rate reached 42% and 80%,respectively. However, energy requirement for aeration exceeded energy savings from the lower volume for sanitation after thedigestion substantially. On a system level, a positive energy balance could still be achieved by taking energy savings from thereplacement of mineral fertilizer (36 GJ per ton NH4) into account. Moreover, the digestate as fertilizer could be applied in amore demand-oriented way by adding ammonium sulphate obtained by the ammonia stripping during the post-treatment.

  • 155.
    Wallin, Fredrik
    et al.
    Mälardalens högskola, Institutionen för samhällsteknik.
    Bartusch, Cajsa
    Mälardalens högskola, Institutionen för samhällsteknik.
    Thorin, Eva
    Mälardalens högskola, Institutionen för samhällsteknik.
    Bäckström, Tobias
    Smedjebacken Energi Nät AB.
    Dahlquist, Erik
    Mälardalens högskola, Institutionen för samhällsteknik.
    The Use of Automatic Meter Readings for a Demand-Based Tariff2005Inngår i: Proceedings of the 2005 IEEE/PES Transmission and Distribution Conference & Exhibition: Asia and Pacific, 2005, s. 1-6Konferansepaper (Fagfellevurdert)
    Abstract [en]

    A determining factor for a successful implementation of a demand-based pricing model or control strategy in electricity markets is not only the effects of peak load management, but also the financial consequences for the utility operator and the end customer. In this economic modelling a subset of 460 residential customers has been implemented in a software tool analysing the economic outcome of three different tariffs. Two demand-based tariffs were investigated and compared with a traditional energy-based tariff. The demand-based tariffs transform the flat income curve into a more complex, due to a stronger economic dependency to the system peak loads. The demand-based tariffs move the revenues to the high-peak period, November – March, and the utility operator gains a good matching between system peaks and distribution of incomes.

  • 156.
    Wallin, Fredrik
    et al.
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Bartusch, Cajsa
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Thorin, Eva
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Dahlquist, Erik
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Important parameters for prediction of power loads - a bottom-up approach utilizing measurements from an automatic meter reading system2007Inngår i: IEEE PES Power Africa 2007 Conference and Exposition, 2007, s. 1-7Konferansepaper (Fagfellevurdert)
  • 157.
    Wallin, Fredrik
    et al.
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Dotzauer, Erik
    Fortum.
    Thorin, Eva
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Dahlquist, Erik
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Automatic meter reading provides opportunities for new prognosis and simulation methods2007Inngår i: 2007 IEEE Lausanne POWERTECH, Proceedings, 2007, s. 2006-2011Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The use of top-down models, for load forecasting purposes, has been the dominating method over the last decades. However, there is now a discussion regarding the performance of the top-down models, e.g. in situations with unusual weather conditions due to the lack of historical data. This paper considers an alternative bottom-up approach with a stronger relation to the laws of physics. Electricity companies in Sweden are installing automatic meter reading systems for their customers, and using the consumption data gives new possibilities when adapting the modeling parameters in a bottom-up model for each single customer. A method for analyzing individual consumption series is suggested, where different periods in time is used to divide and identify different parts of the electricity load; base load, heat load and household loads. A review of previous work is presented, and suggestions how to link the load analysis to construction parameters for an individual building is proposed.

  • 158.
    Wallin, Fredrik
    et al.
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Thorin, Eva
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Kvarnström, Andreas
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Kvarnström, Johan
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Dahlquist, Erik
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    A method to refine electricity consumption data from automatic meter reading systems2006Inngår i: Proceedings of the 2006 International Conference on Power System Technology, IEEE , 2006, s. 1-6Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In this work data from an AMR system delivering consumption data on a daily basis with an aggregated electricity consumption post combined with a maximum peak load within the period has been utilized. The paper suggests a method to create individual hour based daily consumption profiles and to increase the knowledge of the aggregated consumption patterns over the day. As a validation the method has been applied on rearranged data from an AMR system providing hour based metering series to regenerate the same consumption series. Implementing the method can provide consumption series that can be used to increase the accuracy e.g. when forecasting the electricity consumption for individual customers. The created consumption series can also be a valuable resource when estimating aggregated hour based profiles for different areas using a bottom-up approach.

  • 159.
    Wang, Bin
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Tianjin Univ Commerce, Key Lab Refrigerat Technol Tianjin, Peoples R China..
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Tianjin Univ Commerce, Key Lab Refrigerat Technol Tianjin, Peoples R China..
    Yan, Jinying
    KTH Royal Inst Technol, Stockholm, Sweden..
    Thorin, Eva
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Schwede, Sebastian
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Zhu, Kai
    Tianjin Univ Commerce, Key Lab Refrigerat Technol Tianjin, Peoples R China..
    Modelling the Quench Tower in Flue Gas Cleaning of a Waste Fueled Power Plant2018Inngår i: JOINT INTERNATIONAL CONFERENCE ON ENERGY, ECOLOGY AND ENVIRONMENT ICEEE 2018 AND ELECTRIC AND INTELLIGENT VEHICLES ICEIV 2018, DESTECH PUBLICATIONS, INC , 2018Konferansepaper (Fagfellevurdert)
    Abstract [en]

    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.

  • 160.
    Wang, Xiaoqiang
    et al.
    National Engineering Laboratory for Biomass Power Generation Equipment (NELB), School of Renewable Energy, North China Electric Power University.
    Nordlander, Eva
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Thorin, Eva
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Yan, Jinyue
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Microalgal Biomethane Production Integrated with an Existing Biogas Plant: A Case Study in Sweden2012Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Microalgae are considered as potential sources for biodiesel production due to the higher growth rate than terrestrial plants. However, the large-scale application of algal biodiesel would be limited by the downstream cost of lipid extraction and the availability of water, CO2 and nutrients. A possible solution is to integrate algae cultivation with existing biogas plant, where algae can be cultivated using the discharges of CO2 and digestate as nutrient input, and then the attained biomass can be converted directly to biomethane by existing infrastructures. This integrated system is investigated and evaluated in this study. Algae are cultivated in a photobioreactor in a greenhouse, and two cultivation options (greenhouse with and without heating) are included. Life cycle assessment of the system was conducted, showing that algal biomethane production without greenhouse heating would have a net energy ratio of 1.54, which is slightly lower than that (1.78) of biomethane from ley crop. However, land requirement of the latter is approximately 68 times that of the former, because the area productivity of algae could reach at about 400 t/ha (dry basis) in half a year, while the annual productivity of ley crop is only about 5.8 t/ha. For the case of Växtkraft biogas plant in Västerås, Sweden, the integrated system has the potential to increase the annual biomethane output by 9.4 %. This new process is very simple, which might have potential for scale-up and commercial application of algal bioenergy.

    Fulltekst (pdf)
    R10486 Final Paper- ICAE2012- A10560
  • 161.
    Wang, Xiaoqiang
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. North China Electric Power University, Beijing.
    Nordlander, Eva
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Thorin, Eva
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Royal Institute of Technology.
    Microalgal biomethane production integrated with an existing biogas plant: A case study in Sweden2013Inngår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 112, s. 478-484Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Microalgae are considered as potential sources for biodiesel production due to the higher growth rate than terrestrial plants. However, the large-scale application of algal biodiesel would be limited by the downstream cost of lipid extraction and the availability of water, CO2 and nutrients. A possible solution is to integrate algae cultivation with existing biogas plant, where algae can be cultivated using the discharges of CO2 and digestate as nutrient input, and then the attained biomass can be converted directly to biomethane by existing infrastructures. This integrated system is investigated and evaluated in this study. Algae are cultivated in a photobioreactor in a greenhouse, and two cultivation options (greenhouse with and without heating) are included. Life cycle assessment of the system was conducted, showing that algal biomethane production without greenhouse heating would have a net energy ratio of 1.54, which is slightly lower than that (1.78) of biomethane from ley crop. However, land requirement of the latter is approximately 68 times that of the former, because the area productivity of algae could reach at about 400 t/ha (dry basis) in half a year, while the annual productivity of ley crop is only about 5.8 t/ha. For the case of Växtkraft biogas plant in Västerås, Sweden, the integrated system has the potential to increase the annual biomethane output by 9.4%. This new process is very simple, which might have potential for scale-up and commercial application of algal bioenergy. © 2013 Elsevier Ltd. All rights reserved.

  • 162.
    Yuting, Tan
    et al.
    Royal Institute of Technology, Sweden.
    Nookuea, Worrada
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Thorin, Eva
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Royal Institute of Technology, Stockholm, Sweden.
    Property Impacts on Plate-fin Multi-stream Heat Exchanger (Cold Box) Design in CO2 Cryogenic Process: Part II. Evaluation of Viscosity and Thermal Conductivity Models2017Inngår i: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 105, s. 4595-4600Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Viscosity and thermal conductivity are key transport properties in the design of plate-fin multi-stream heat exchanger in CO2 cryogenic processes. It is necessary to evaluate the reliabilities of viscosity and thermal conductivity models. In addition, the differences in design of multi-stream heat exchanger by using different property models need to be studied as well. In this paper, viscosity models and thermal conductivity models of CO2 mixtures with non-condensable gas impurities were evaluated separately by comparison with existing experimental data. Recommendations were given on model selections and their impact on the design of plate-finmulti-stream heat exchanger were analyzed.

    The results show that for viscosity, the uncertainty range of Wilke’s model is the smallest with a maximum absolute deviation of 6.1%. This model is therefore recommended to be used. For thermal conductivity, GERG model, with a maximum absolute deviation of 8.7% is preferred. The choice of thermal conductivity model has a noticeabl eimpact on the plate-fin multi-stream heat exchanger design, and the maximum deviation by using different thermal conductivity models is 7.5%

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