| 1. |
- Dahlquist, Erik, 1951-, et al.
(författare)
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Control of waste water treatment combined with irrigation
- 2019
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Konferensbidrag (refereegranskat)abstract
- In waste water treatment using biological treatment processes normally phosphorous, nitrous compounds as well as organic matterare removed.It is also important to remove or kill pathogens that otherwisecould cause diseases. The surplus of bio-sludge is used to produce biogas. In thepaper four different alternatives for system design and operations of systems was discussed. The alternatives integrates thewaste water treatment and irrigation offarmland using the water taken out from different positions in the waste water treatment plant.
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| 2. |
- Dahlquist, Erik, et al.
(författare)
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Modelling and Simulation of Biomass Conversion Processes
- 2015
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Ingår i: Proceedings - 8th EUROSIM Congress on Modelling and Simulation, EUROSIM 2013. - 9780769550732 ; , s. 506-512
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Konferensbidrag (refereegranskat)abstract
- By utilizing biomass gasification, the energy contentof the biomass can be utilized to produce gas to be used forcogeneration of heat and power as well as other energy carrierssuch as fuels for vehicles. The concept is suitable forapplication to existing CHP plants as well as for utilizing spentliqour in small scale pulp and paper mills. The introductionwould enable flexible energy utilization, use of problematicfuels as well as protects the environment by e.g. avoiding therelease of toxic substances. In this paper, the possibilities todevelop this concept is discussed. In this paper we comparedifferent gasification processes with respect to what gas qualitywe get, and how the gasification can be modelled usingdifferent modelling approaches, and how these can becombined. Results from simulations are compared toexperimental results from pilot plant operations in differentscales and with different processes like CFB and BFBTechnologies, athmospheric and pressurized, and using steam,air and oxygen as oxidizing media.
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| 3. |
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| 4. |
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| 5. |
- Li, Hailong, et al.
(författare)
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Feasibility study on combining anaerobic digestion and biomass gasification to increase the production of biomethane
- 2015
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Ingår i: Energy Conversion and Management. - : Elsevier BV. - 0196-8904 .- 1879-2227. ; 100, s. 212-219
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Tidskriftsartikel (refereegranskat)abstract
- There is a rapid growing interest in using biomethane as fuel for transport applications. A new concept is proposed to combine anaerobic digestion and biomass gasification to produce biomethane. H-2 is separated from the syngas generated by biomass gasification in a membrane system, and then is used to upgrade raw biogas from anaerobic digestion. Simulations have been conducted based on the real operation data of one full scale biogas plant and one full scale biomass gasification plant in order to investigate the feasibility of the new concept. Results show that although less power and heat are generated compared to the gasification plant, which results in a lower overall efficiency, much more biomethane can be produced than the biogas plant; and the new concept can achieve a higher exergy efficiency. Due to the increasing price of biomethane, the novel concept demonstrates a big potential of income increase. For example, at a biomethane price of 12.74SEK/kg, the annual income can be increased by 53% compared to the total income of the biogas and gasification plant. (C) 2015 Elsevier Ltd. All rights reserved.
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| 6. |
- Li, Hailong, 1976-, et al.
(författare)
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Using the solid digestate from a wet anaerobic digestion process as an energy resource
- 2013
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Ingår i: Energy technology. - : Wiley. - 2194-4296 .- 2194-4288. ; 1:1, s. 94-101
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Tidskriftsartikel (refereegranskat)abstract
- The wet anaerobic digestion process is a widely used method to produce biogas from biomass. To avoid the risks involved with using the digestion waste as a fertilizer, this work investigates the possibilities to use the solid digestate as an energy resource to produce heat and electricity, which could save some energy currently consumed by the plant and, therefore, may increase the overall efficiency of a biogas plant. Simulations were conducted based on real data from the Växtkraft biogas plant in Västerås, Sweden as a case study. Results show that it is necessary to dry the solid digestate before combustion and include flue-gas condensation to recover enough heat for the drying process. When a steam turbine cycle is integrated, the generated electricity could cover 13–18 % of the total electricity consumption of the plant, depending on the degree of dryness. In addition, reducing the digestion period can increase the carbon content (ultimate analysis), the heating value, and the mass flow of the solid digestate. As a result, the production of electricity and heat is augmented in the steam turbine cycle. However, the production of biogas is reduced. Therefore, a comprehensive economic evaluation is suggested to optimize a biogas plant that uses the solid digestate from a wet anaerobic digestion process as an energy resource.
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| 7. |
- Marais, Heidi L., 1996-, et al.
(författare)
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Outlining Process Monitoring and Fault Detection in a Wastewater Treatment and Reuse System
- 2020
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Ingår i: European Control Conference 2020, ECC 2020. - : Institute of Electrical and Electronics Engineers Inc.. - 9783907144015 ; , s. 558-563
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Konferensbidrag (refereegranskat)abstract
- Process control is an important part of any industrial system. In a wastewater reuse system this remains true. Process monitoring and fault detection (FD) are important to ensure that the control system has access to reliable data which can be used in making decisions about the operation of the process. The reuse scenario being considered in this work is that of utilizing the nutrients from the wastewater as fertilizer to agricultural soil along with using the water for irrigation purposes. This paper identifies variables that are important to the control of the process and should be a focus of monitoring and FD. In wastewater treatment these variables include temperatures, pressures, liquid levels, flow rates, pH, conductivity, biomass content, suspended solids concentration, dissolved oxygen content, total organic carbon, and the concentrations of nitrate and ammonium. The variables of interest in the reuse of nutrients and water for agriculture include soil moisture, ambient conditions, plant height, biomass content, photosynthetic activity of the crop, leaf area and leaf water content, as well as the concentrations of several ions both in the soil and in the plant. Challenges associated with process monitoring and FD specific to the two processes are also discussed, examples of these are the high dimensionality of the problem, the harsh conditions that sensors must operate in and the non-linear relationships between variables. This information will be used in future work when comparing specific FD methods to ensure that methods chosen are capable of overcoming the commonly encountered problems.
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| 8. |
- Nordlander, Eva, et al.
(författare)
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Energy Efficiency Evaluation of two Biogas Plants
- 2011
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Konferensbidrag (refereegranskat)abstract
- Anaerobic digestion for biogas production is a promising renewable energy technology whichcan be used to achieve environmental goals set in the European Union and other regions. Thereare however many improvements that can still be made to the process. Furthermore, there arealternative energy conversion processes that compete for some of the substrates used inanaerobic digestion. Energy efficiency could therefore be a tool for measuring and comparingthe performance of biogas plants. This study suggests a method for calculating energyefficiency of the biogas plant so that it is comparable to other processes. Two examples ofexisting biogas plants in Sweden have been selected for the efficiency assessment by using themethod proposed in this paper. The results are compared between the plants to assess thefurther potential of improvement.
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| 9. |
- Nordlander, Eva, et al.
(författare)
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Investigating the possibility of applying an ADM1 based model to a full-scale co-digestion plant
- 2017
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Ingår i: Biochemical engineering journal. - : Elsevier. - 1369-703X .- 1873-295X. ; 120, s. 73-83
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Tidskriftsartikel (refereegranskat)abstract
- This study investigated the possibility of using a model based on the anaerobic digestion model no. 1 (ADM1) on a full-scale 4000 m3 digester in order to understand how such theoretical models can be applied to a real industrial process. The industrial scale digester co-digests the organic fraction of municipal solid waste, grease trap sludge, and ley crop silage with varying feed rates and amounts of volatile solids. A year of process data was collected. Biogas flow, methane content/flow, and ammonia nitrogen were the variables that the model was best at predicting (index of agreement at 0.78, 0.61/0.77, and 0.68, respectively). The model was also used to investigate the effect of increasing the volatile solids (VS) concentration entering the digester. According to simulation results, increasing the influent VS concentration will increase biogas and methane outflow (from 1.5 million Nm3 methane to more than 2 million Nm3 methane), but decrease the amounts of biogas/methane per unit of volatile solids (from about 264 Nm3 methane per tonne VS to below 215 Nm3 methane per tonne VS).
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| 10. |
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