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Lu, H., Yu, X., Li, H., Schwede, S. & Tu, S.-T. -. (2019). Accurately measurement and efficiently recovery of ionic liquid in energy utilization of microalgae. In: Energy Procedia: . Paper presented at 10th International Conference on Applied Energy, ICAE 2018, 22 August 2018 through 25 August 2018 (pp. 1337-1341). Elsevier Ltd, 158
Open this publication in new window or tab >>Accurately measurement and efficiently recovery of ionic liquid in energy utilization of microalgae
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2019 (English)In: Energy Procedia, Elsevier Ltd , 2019, Vol. 158, p. 1337-1341Conference paper, Published paper (Refereed)
Abstract [en]

Chlorella vulgais, a kind of micro-alagae, is an attracting feedstock for bioenergy production, such as biodiesel and biogas. But its tough cell wall structure is the main obstacle to efficiently extracting lipids and other biomass. Ionic liquid (IL) can be used to hydrolyze its cell-wall. However, due to its high cost and toxicity, it is important to recover IL as much as possible. Therefore, a method that can accurately measure the content of ILs, is urgently needed. In this work, two common methods that are used to measure the content of ILs: equimolar titration method and ultraviolet absorbance spectra were compared. The results show that equimolar titration method is not available for trace quantity analysis of ionic liquids as the endpoint of titration is hard to be identified at low IL content (<10 mg/L); while UV absorbance spectra method can be used at low IL contents, whereas, it may result in big deviations. To further improve the accuracy of UV absorbance spectra method, concentrating the sample could be a potential solution.

Place, publisher, year, edition, pages
Elsevier Ltd, 2019
Keywords
Chlorella, Industrial ionic liquid, Lipids extraction, Biomass, Energy utilization, Lipids, Titration, Bioenergy productions, Cell wall structure, Cell walls, Micro-algae, Quantity analysis, Ultraviolet absorbance, UV absorbance spectra, Ionic liquids
National Category
Energy Engineering
Identifiers
urn:nbn:se:mdh:diva-43193 (URN)10.1016/j.egypro.2019.01.328 (DOI)000471031701108 ()2-s2.0-85063873518 (Scopus ID)
Conference
10th International Conference on Applied Energy, ICAE 2018, 22 August 2018 through 25 August 2018
Available from: 2019-04-25 Created: 2019-04-25 Last updated: 2019-07-11Bibliographically approved
Salman, C. A., Schwede, S., Thorin, E., Li, H. & Yan, J. (2019). Identification of thermochemical pathways for the energy and nutrient recovery from digested sludge in wastewater treatment plants. In: Energy Procedia: . Paper presented at 10th International Conference on Applied Energy, ICAE 2018, 22 August 2018 through 25 August 2018 (pp. 1317-1322). Elsevier Ltd, 158
Open this publication in new window or tab >>Identification of thermochemical pathways for the energy and nutrient recovery from digested sludge in wastewater treatment plants
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2019 (English)In: Energy Procedia, Elsevier Ltd , 2019, Vol. 158, p. 1317-1322Conference paper, Published paper (Refereed)
Abstract [en]

There are several restrictions and limitations on the emissions and disposal of materials and pollutants related to wastewater treatment plants (WWTPs) emphasizing improvement of current processes and development of new methods. Process integration is one way to use all fractions of waste for improved efficiency. WWTPs produces sludge which is usually anaerobically digested to produce biogas and a byproduct called digestate. Digestate is an organic material that contains macro and micronutrients such as nitrogen, phosphorous, and potassium and also contains heavy metals. Digestate is mainly used for agricultural applications because of the presence of nutrients. However, digestate also contains energy in the form of carbon and hydrogen which can be harnessed through various processes and integrated with nitrogen recovery process. This study aims to recover the energy and nutrients from digestate through thermochemical treatment processes. Combustion, pyrolysis, and gasification are assessed and compared in this work. An ammonia stripping method is assumed to recover nitrogen from digestate. The thermochemical processes are heat integrated with ammonia stripping through modeling and simulation. Results show that almost half of the energy present in digested sludge is required for its drying. Moreover, nitrogen recovery also requires much energy. The combustion and gasification of digested sludge give better results than pyrolysis. The heat integration becomes feasible when the auxiliary biogas is also burned along with products from the thermochemical treatment of sludge.

Place, publisher, year, edition, pages
Elsevier Ltd, 2019
Keywords
Combustion, Digestate, Gasification, Pyrolysis, Wastewater treatment, Ammonia, Anaerobic digestion, Biogas, Heavy metals, Nitrogen, Nutrients, Reclamation, Sewage pumping plants, Waste incineration, Wastewater disposal, Water treatment plants, Carbon and hydrogens, Macro-and micronutrients, Model and simulation, Process integration, Thermo chemical process, Thermochemical treatments, Wastewater treatment plants
National Category
Energy Engineering
Identifiers
urn:nbn:se:mdh:diva-43184 (URN)10.1016/j.egypro.2019.01.325 (DOI)000471031701105 ()2-s2.0-85063872188 (Scopus ID)
Conference
10th International Conference on Applied Energy, ICAE 2018, 22 August 2018 through 25 August 2018
Available from: 2019-04-26 Created: 2019-04-26 Last updated: 2019-07-11Bibliographically approved
Lu, H., Yu, X., Li, H., Tu, S.-T. -. & Schwede, S. (2019). Lipids extraction from wet Chlorella pyrenoidosa sludge using recycled [BMIM]Cl. Bioresource Technology, 291, Article ID 121819.
Open this publication in new window or tab >>Lipids extraction from wet Chlorella pyrenoidosa sludge using recycled [BMIM]Cl
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2019 (English)In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 291, article id 121819Article in journal (Refereed) Published
Abstract [en]

In this study, experiments on pretreating one species of microalgae (Chlorella pyrenoidosa) using one kind of ionic liquid (IL) of [BMIM]Cl were conducted. The aim of this work is to evaluate the recycling efficacy of expensive IL solvent for effective cell disruption. It was indicated that the molecular structure of IL was stable during the recycling test. Five times antisolvent precipitation of microalgae debris after lipid extraction using methanol recovered 99.8% IL with the energy consumption of 4.46 MJ per kg dry Chlorella pyrenoidosa. The chromatography was used to separate IL and hydrolysates, resulting in the IL loss below 1.97 g per kg dry Chlorella pyrenoidosa. © 2019 Elsevier Ltd

Place, publisher, year, edition, pages
Elsevier Ltd, 2019
National Category
Environmental Engineering
Identifiers
urn:nbn:se:mdh:diva-44963 (URN)10.1016/j.biortech.2019.121819 (DOI)000480326200058 ()31369925 (PubMedID)2-s2.0-85069817980 (Scopus ID)
Available from: 2019-08-08 Created: 2019-08-08 Last updated: 2019-10-14Bibliographically approved
Li, H., Wang, B., Yan, J., Salman, C. A., Thorin, E. & Schwede, S. (2019). Performance of flue gas quench and its influence on biomass fueled CHP. Energy, 180, 934-945
Open this publication in new window or tab >>Performance of flue gas quench and its influence on biomass fueled CHP
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2019 (English)In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 180, p. 934-945Article in journal (Refereed) Published
Abstract [en]

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. 

Place, publisher, year, edition, pages
Elsevier Ltd, 2019
Keywords
Biomass and waste fueled CHP, Energy efficiency, Flue gas cleaning, Flue gas quench, Water balance
National Category
Energy Engineering
Identifiers
urn:nbn:se:mdh:diva-44660 (URN)10.1016/j.energy.2019.05.078 (DOI)000474315800074 ()2-s2.0-85067066514 (Scopus ID)
Available from: 2019-06-27 Created: 2019-06-27 Last updated: 2019-10-11Bibliographically approved
Salman, C. A., Schwede, S., Naqvi, M., Thorin, E. & Yan, J. (2019). Synergistic combination of pyrolysis, anaerobic digestion, and CHP plants.. In: Energy Procedia: . Paper presented at 10th International Conference on Applied Energy, ICAE 2018, 22 August 2018 through 25 August 2018 (pp. 1323-1329). Elsevier Ltd, 158
Open this publication in new window or tab >>Synergistic combination of pyrolysis, anaerobic digestion, and CHP plants.
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2019 (English)In: Energy Procedia, Elsevier Ltd , 2019, Vol. 158, p. 1323-1329Conference paper, Published paper (Refereed)
Abstract [en]

The anaerobic digestion of biodegradable fraction of municipal solid waste (MSW) is a widely used process for biogas production. However, the biodegradable fraction of MSW also contains lignocellulosic waste which hinders the biogas production if added to the digester in higher quantity. So it needs to be separated from biodegradable waste and sent for alternate treatment, e.g., incineration, landfilling or compositing. Pyrolysis of lignocellulosic waste to produce biochar, syngas, and bio oil is an alternate treatment to consider. Furthermore, there is a reported correlation between the addition of biochar in the digester and higher biogas production. Previously, we coupled the pyrolysis of lignocellulosic waste with anaerobic digestion plant. Pyrolysis produces the biochar and vapors. Biochar was added in the digester to enhance the biomethane production. The vapors produced in the pyrolysis process were converted to biomethane through the catalytic methanation process. The combination gives the overall efficiency of 67%. In this work, we modified the process concept to increase the integration level of these processes. The main issue with the pyrolysis process is its heat required to operate, while some of its downstream processes also generate excess heat. In this study, the pyrolysis of lignocellulosic waste is integrated with an operating combined heat and power (CHP) plant, by using its existing infrastructure for heat transport among different pyrolysis operations. The combustor of the CHP plant provides the heat for drying and pyrolysis while the excess heat is transferred back to the combustor. The biochar produced from pyrolysis is transported back to the digester as an adsorbent. The process simulation results show that the combined efficiency of pyrolysis with CHP plant reached 80%. If the biochar is sent back to the anaerobic digester, the synergetic efficiency of all three processes, i.e., pyrolysis-CHP and anaerobic digestion was obtained at 79.7% as compared with the 67% efficiency when the pyrolysis was only integrated with the anaerobic digestion process.

Place, publisher, year, edition, pages
Elsevier Ltd, 2019
Keywords
Heat integration, Lignocellulosic waste, Municipal solid waste, Biogas, Cogeneration plants, Combustors, Power generation, Pyrolysis, Waste incineration, Anaerobic digestion process, Biodegradable fraction, Biodegradable wastes, Combined heat and power, Lignocellulosic wastes, Municipal solid waste (MSW), Synergistic combinations, Anaerobic digestion
National Category
Energy Engineering
Identifiers
urn:nbn:se:mdh:diva-43183 (URN)10.1016/j.egypro.2019.01.326 (DOI)000471031701106 ()2-s2.0-85063896503 (Scopus ID)
Conference
10th International Conference on Applied Energy, ICAE 2018, 22 August 2018 through 25 August 2018
Available from: 2019-04-26 Created: 2019-04-26 Last updated: 2019-07-11Bibliographically approved
Olsson, J., Forkman, T., Gentili, F., Zambrano, J., Schwede, S., Nehrenheim, E. & Thorin, E. (2018). Anaerobic co-digestion of sludge and microalgae grown inmunicipal wastewater: A feasibility study. Water Science and Technology, 77(3), 682-694
Open this publication in new window or tab >>Anaerobic co-digestion of sludge and microalgae grown inmunicipal wastewater: A feasibility study
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2018 (English)In: Water Science and Technology, ISSN 0273-1223, E-ISSN 1996-9732, Vol. 77, no 3, p. 682-694Article in journal (Refereed) Published
Abstract [en]

In this study a natural mix of microalgae grown in wastewater of municipal character was co-digested with sewage sludge in mesophilic conditions, in both batch and semi-continuous modes. The semicontinuous experiment was divided into two periods with OLR 1 (Organic Loading Rate) of 2.4 kg VS m3 d-1 and HRT1 (Hydraulic Retention Time) of 15 days, and OLR2 of 3.5 kg VS m3 d-1 and HRT2 of 10 days respectively. Results showed stable conditions during both periods. The methane yield was reduced when adding microalgae (from 200 ± 25 NmL CH4 g VSin-1 , to 168±22 NmL CH4 g VSin-1). VS reduction was also decreased by 51%. This low digestability was confirmed in the anaerobic batch test. However, adding microalgae improved the dewaterability of the digested sludge. The high heavy metals content in the microalgae resulted in a high heavy metals content in the digestate, making it more difficult to reuse the digestate as fertilizer on arable land. The heavy metals are thought to originate from the flue gas used as a CO2 source during the microalgae cultivation. Therefore the implementation of CO2 mitigation via algal cultivation requires careful consideration regarding thesource of the CO2-rich gas.

Keywords
Biogas, dewaterability, Gompertz model, mesophilic, semi-continuous study, waste activated sludge
National Category
Renewable Bioenergy Research Water Engineering
Research subject
Energy- and Environmental Engineering
Identifiers
urn:nbn:se:mdh:diva-37381 (URN)10.2166/wst.2017.583 (DOI)000424765000013 ()29431713 (PubMedID)2-s2.0-85042218057 (Scopus ID)
Projects
MAASICA-projektet
Funder
Knowledge Foundation
Available from: 2017-12-04 Created: 2017-12-04 Last updated: 2019-06-18Bibliographically approved
Thorin, E., Olsson, J., Schwede, S. & Nehrenheim, E. (2018). Co-digestion of sewage sludge and microalgae: Biogas production investigations. Applied Energy, 227, 64-72
Open this publication in new window or tab >>Co-digestion of sewage sludge and microalgae: Biogas production investigations
2018 (English)In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 227, p. 64-72Article in journal (Refereed) Published
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.

Keywords
Biomass Wastewater treatment Batch Continuous BMP Anaerobic digestion
National Category
Other Engineering and Technologies not elsewhere specified
Identifiers
urn:nbn:se:mdh:diva-37578 (URN)10.1016/j.apenergy.2017.08.085 (DOI)000445987200007 ()2-s2.0-85028066228 (Scopus ID)
Projects
MAASICA
Funder
Knowledge Foundation
Available from: 2017-12-27 Created: 2017-12-27 Last updated: 2018-12-18Bibliographically approved
Olsson, J., Schwede, S., Nehrenheim, E. & Thorin, E. (2018). Microalgae as biological treatment for municipal wastewater - Effects on the sludge handling in a treatment plant. Water Science and Technology, 78(3), 644-654
Open this publication in new window or tab >>Microalgae as biological treatment for municipal wastewater - Effects on the sludge handling in a treatment plant
2018 (English)In: Water Science and Technology, ISSN 0273-1223, E-ISSN 1996-9732, ISSN 0273-1223, Vol. 78, no 3, p. 644-654Article in journal (Refereed) Published
Abstract [en]

A mix of microalgae and bacteria was cultivated on pre-sedimented municipal wastewater in a continuous operated microalgae-activated sludge process. The excess material from the process was co-digested with primary sludge in mesophilic and thermophilic conditions in semi-continuous mode (5 L digesters). Two reference digesters (5 L digesters) fed with waste-activated sludge (WAS) and primary sludge were operated in parallel. The methane yield was slightly reduced (≈10%) when the microalgal-bacterial substrate was used in place of the WAS in thermophilic conditions, but remained approximately similar in mesophilic conditions. The uptake of heavy metals was higher with the microalgal-bacterial substrate in comparison to the WAS, which resulted in higher levels of heavy metals in the digestates. The addition of microalgal-bacterial substrate enhanced the dewaterability in thermophilic conditions. Finally, excess heat can be recovered in both mesophilic and thermophilic conditions. 

Place, publisher, year, edition, pages
IWA Publishing, 2018
Keywords
Dewaterability, Heat balance, Heavy metals, Microalgae, Semi-continuous study, Waste activated sludge, Algae, Anaerobic digestion, Biological water treatment, Microorganisms, Wastewater treatment, Micro-algae, Semi-continuous, Waste activated sludges, Activated sludge process, Bacteria (microorganisms)
National Category
Water Engineering
Identifiers
urn:nbn:se:mdh:diva-41017 (URN)10.2166/wst.2018.334 (DOI)000445518100018 ()30208005 (PubMedID)2-s2.0-85053616456 (Scopus ID)
Available from: 2018-09-27 Created: 2018-09-27 Last updated: 2019-06-18Bibliographically approved
Wang, B., Li, H., Yan, J., Thorin, E., Schwede, S. & Zhu, K. (2018). Modelling the Quench Tower in Flue Gas Cleaning of a Waste Fueled Power Plant. In: JOINT INTERNATIONAL CONFERENCE ON ENERGY, ECOLOGY AND ENVIRONMENT ICEEE 2018 AND ELECTRIC AND INTELLIGENT VEHICLES ICEIV 2018: . Paper presented at International Conference on Energy, Ecology and Environment (ICEEE) / International Conference on Electric and Intelligent Vehicles (ICEIV), NOV 21-25, 2018, Swinburne Univ Technol, Melbourne, AUSTRALIA. DESTECH PUBLICATIONS, INC
Open this publication in new window or tab >>Modelling the Quench Tower in Flue Gas Cleaning of a Waste Fueled Power Plant
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2018 (English)In: JOINT INTERNATIONAL CONFERENCE ON ENERGY, ECOLOGY AND ENVIRONMENT ICEEE 2018 AND ELECTRIC AND INTELLIGENT VEHICLES ICEIV 2018, DESTECH PUBLICATIONS, INC , 2018Conference paper, Published paper (Refereed)
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.

Place, publisher, year, edition, pages
DESTECH PUBLICATIONS, INC, 2018
Series
DEStech Transactions on Environment Energy and Earth Sciences, ISSN 2475-8833
Keywords
flue gas, quench, mathematic model, temperature of exit FG, water consumption
National Category
Energy Engineering
Identifiers
urn:nbn:se:mdh:diva-43986 (URN)000468631900126 ()978-1-60595-590-2 (ISBN)
Conference
International Conference on Energy, Ecology and Environment (ICEEE) / International Conference on Electric and Intelligent Vehicles (ICEIV), NOV 21-25, 2018, Swinburne Univ Technol, Melbourne, AUSTRALIA
Available from: 2019-06-12 Created: 2019-06-12 Last updated: 2019-06-12Bibliographically approved
Thorin, E., Olsson, J., Schwede, S. & Nehrenheim, E. (2017). Biogas from Co-digestion of Sewage Sludge and Microalgae. In: Energy Procedia: . Paper presented at The 8th International Conference on Applied Energy – ICAE2016 (pp. 1037-1042). , 105
Open this publication in new window or tab >>Biogas from Co-digestion of Sewage Sludge and Microalgae
2017 (English)In: Energy Procedia, 2017, Vol. 105, p. 1037-1042Conference paper, Published paper (Refereed)
Abstract [en]

Microalgae cultivated in waste water could contribute to increased biomass production at municipal waste watertreatment plants. The biomass could be utilized for biogas production when co-digested with sewage sludge. In thispaper previous published results on co-digestion of sewage sludge and microalgae are summarized and remainingknowledge gaps are identified. The available batch tests in literature mostly concern digestion at mesophilicconditions. Some of those tests indicate a synergetic effect for the co-digestion. Investigations at thermophilicconditions and of semi-continuous processes are scarce. The available results show good possibilities for co-digestionof sewage sludge and microalgae. Further investigations are needed to find optimal conditions for biogas production.

Keywords
biomass; waste water treatement; batch; continous; BMP; anaerobic digestion
National Category
Other Engineering and Technologies not elsewhere specified
Identifiers
urn:nbn:se:mdh:diva-37579 (URN)10.1016/j.egypro.2017.03.449 (DOI)000404967901020 ()2-s2.0-85020740140 (Scopus ID)
Conference
The 8th International Conference on Applied Energy – ICAE2016
Projects
MAASICA
Funder
Knowledge Foundation
Available from: 2017-12-27 Created: 2017-12-27 Last updated: 2018-07-25Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-5014-3275

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