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- Avelin, Anders, et al.
(författare)
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Use of combined physical and statistical models for online applications in the pulp and paper industry
- 2009
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Ingår i: Mathematical and Computer Modelling of Dynamical Systems. - : Informa UK Limited. - 1387-3954 .- 1744-5051. ; 15:5, s. 425-434
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Tidskriftsartikel (refereegranskat)abstract
- This paper discusses the accuracy of different types of models. Statistical models are based on process data and/or observations from lab measurements. This class of models are called black box models. Physical models use physical relationships to describe a process. These are called white box models or first principle models. The third group is sometimes called grey box models, being a combination of black box and white box models. Here we discuss two examples of model types. One is a statistical model where an artificial neural network is used to predict NOx in the exhaust gases from a boiler at Mlarenergi AB in Vsters, Sweden. The second example is a grey box model of a continuous digester. The digester model includes mass balances, energy balances, chemical reactions and physical geometrical constraints to simulate the real digester. We also propose that a more sophisticated model is not required to increase the accuracy of the predicted measurements.
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| 6. |
- Lindhult, Erik, et al.
(författare)
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Innovation capabilities and challenges for energy smart development in medium sized European cities
- 2016
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Ingår i: Energy Procedia. - : Elsevier BV. - 1876-6102. ; :88, s. 205-211
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Tidskriftsartikel (refereegranskat)abstract
- Transition towards becoming Energy smart city integrating different areas of energy production, distribution and use in a community requires a spectrum of capabilities. The paper reports on findings from the EU planning project PLEEC, involving six medium sized European cities. The purpose of the paper is to describe innovation capabilities and challenges in the complex, systemic innovation journey of cities in the transition to sustainability. A case of implementing an innovative project for electrical vehicles in Eskilstuna is presented illustrating both technological potentials and innovation challenges.
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| 7. |
- Lindmark, Johan, et al.
(författare)
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Evaluating the effects of electroporation pre-treatment on the biogas yield from ley crop silage.
- 2014
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Ingår i: Applied Biochemistry and Biotechnology. - : Springer Science and Business Media LLC. - 0273-2289 .- 1559-0291. ; 174:7, s. 2616-2625
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Tidskriftsartikel (refereegranskat)abstract
- Exploiting the full biogas potential of some types of biomass is challenging. The complex structures of lignocellulosic biomass are difficult to break down and thus require longer retention times for the nutrients to become biologically available. It is possible to increase the digestibility of the substrate by pre-treating the material before digestion. This paper explores a pre-treatment of ley crop silage that uses electrical fields, known as electroporation (EP). Different settings of the EP equipment were tested, and the results were analyzed using a batch digestion setup. The results show that it is possible to increase the biogas yield with 16 % by subjecting the substrates to 65 pulses at a field strength of 96 kV/cm corresponding to a total energy input of 259 Wh/kg volatile solid (VS). However, at 100 pulses, a lower field strength of 48 kV/cm and the same total energy input, no effects of the treatment were observed. The energy balance of the EP treatment suggests that the yield, in the form of methane, can be up to double the electrical energy input of the process.
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| 8. |
- Lindmark, Johan, et al.
(författare)
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Pre-treatment of Substrate for Increased Biogas Production
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- The full biogas potential of most organic material cannot be exploited with today’s technology. The complex structures of the organic materials are broken down too slowly and the nutrients cannot become biologically available during the relatively short retention time of most digesters. This means that a lot of the bound energy in the organic material leaves the biogas plant with the liquid digestate. There is a possibility to increase the efficiency of the process by pre-treating the material before digestion. This paper explores a pre-treatment of ley crop silage using electrical fields, known as electroporation (EP). Different settings of the EP equipment were tested and the results were analysed using a batch digestion setup. The results from the experiments show that there is a possibility to double the biogas production at typical retention times of a CSTR. The energy balance of the EP equipment suggests that the pre-treatment yield is around 2-6 times larger than the energy input to the process, i.e. energy in the form of methane.
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| 10. |
- Lönnqvist, Tomas, 1979-, et al.
(författare)
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The potential for waste to biogas in La Paz and El Alto in Bolivia
- 2013
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Ingår i: 1st International Water Association Conference on HolisticSludge Management, 2013, Västerås Sweden.
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Konferensbidrag (refereegranskat)abstract
- In the cities of La Paz and El Alto, 573 tons of organic material are disposed in landfills every day. These residues can be used to produce biogas and recycle nutrients, thus alleviating environmental impacts related to waste management. Technical solutions are evaluated through a multicriteria analysis with the purpose of defining a strategy for implementing waste-to-biogas in the two cities. As a result, the development for waste-to-biogas-system is defined in three steps. Step 1 consists of an active extraction system of landfill gas in the already existing landfills. Step 2 implies the establishment of a dry-digestion biogas facility based on present waste collection practices, that is, not segregated waste. Step 3 consists of a biogas plant using dry digestion for processing source segregated bio-waste. The economic feasibility of these three steps is evaluated. Despite prevailing fossil fuels subsidies in the country, implementing waste-to-biogas turn out feasible in the country provided the digestate is commercialized as bio-fertilizer or erosion control material and additional services such as waste collection and deposition are computed in the total economy of the biogas production plant.
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