| 1. |
- Andersson, Jan-Olof, et al.
(författare)
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Improved energy efficiency in juice production through waste heat recycling
- 2013
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Ingår i: International Conference on Applied Energy, ICAE 2013.
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Konferensbidrag (refereegranskat)abstract
- The global demand for Nordic wild berries has increased steadily, partly due to their healthy properties and their good taste. Juice concentrate is produced by pressing berries and heating up the juice. The by-products are berry skins and seeds. Traditionally, the by-products have been composted. Higher competiveness can be achieved by decreasing the production cost and increasing the product values. The berry skins and seeds have a commercial value since they are rich in vitamins and nutrients. To use and sell these by-products, they need to be separated from each other and dried to a moisture content of less than 10 %wt. A berry juice industry in the north of Sweden has been studied in order to increase the energy and resource efficiency and optimize the quality and yield of different berry fractions. This was done by means of process integration with thermodynamics and psychrometry along with measurements of the berry juice production processes. Our calculations show that the drying system could be operated at full without any external heat supply. This could be achieved by increasing the efficiency of the dryer by recirculating 80 % of the drying air and by heating the air with heat from the flue gases from the industrial boiler. This change would decrease the need for heat in the dryer with about 64 %. The total heat use for the plant could thereby be decreased from 1204 kW to 1039 kW. The proposed changes could be done without compromising the production quality or the lead time.
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| 2. |
- Elfgren, Erik, et al.
(författare)
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Exergy as a means for process integration in an integrated steel plant
- 2011
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Konferensbidrag (refereegranskat)abstract
- The Luleå energy system consists of SSAB (an integrated steel plant) – LuleKraft (the heat and power plant) – Luleå Energi (the district heating network). The exergy flows in the whole system have been studied and some possibilities on how to reduce the exergy losses are discussed. The exergy thermal efficiency of SSAB, LuleKraft and Luleå Energi are 70 %, 40 % and 30 % respectively. The relatively low exergy thermal efficiencies is a natural consequence of converting high-value chemical energy into heating water. In the integrated steel plant, the exergy losses are caused by the cooling of the steel prior to transport. In the heat and power plant, exergy is destroyed mainly in the furnace. In the district heating, exergy is destroyed mainly by the customer. A preliminary conclusion is that a lot of exergy is destroyed and lost in order to produce hot water, which doesn’t really need so much exergy. By lowering the water temperature of the district heating, a larger portion of the exergy can be converted to high-value electricity. Mapping by combined Exergy/energy analysis is important to find ways to improve energy efficiency. It can also be important to initiate regional energy collaboration.
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| 3. |
- Elfgren, Erik, et al.
(författare)
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Possibility to Combine Exergy with other Process Integration Methods for a Steelmaking Case
- 2010
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Ingår i: PRES 2010, 13th Conference on Process Integration, Modelling and Optimisation for Energy Saving and Pollution Reduction. - : AIDIC Servizi S.r.l.. - 9788895608051 ; , s. 1375-1380
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Konferensbidrag (refereegranskat)abstract
- The energy system of Luleå consists of the steel plant, a local CHP using process gases from the plant and the district heating system. Process integration work to improve the efficiency of the system is presently carried out by mathematical programming using a MILP tool (reMIND). Further improvements would need an improved possibility of the tool to consider the thermodynamic quality of the energy flows. This project aims to include exergy parameters in the node equations and object functions. This has been carried out for a test case, including a part of the system. Programming principles and some results are described.
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| 4. |
- Grip, Carl-Erik, et al.
(författare)
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Forestry meets Steel. A system study of the possibility to produce DRI (directly Reduced Iron) using gasified biomass.
- 2015
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Ingår i: ECOS 2015 - 28th International Conference on Efficiency, Cost, Optimization, Simulation and Environmental Impact of Energy Systems. - : International Conference on Efficiency, Cost, Optimization, Simulation and Environmental Impact of Energy Systems. - 9782955553909
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Konferensbidrag (refereegranskat)abstract
- The main production of primy Iron from ore is now made by reduction using fossil reductants, either by producing hot metal in the blast furnace process or as directly reduced iron with natural gas as most common reductant. The climate gas impact would be improved if at least pt of the reductants could be produced from Biomass. One possibility could be to use gasified Biomass to produce DRI (Directly Reduced Iron). This is studied in a cooperative project where LTU, MEFOS, ETC and five industries in the eas forestry & pulp, mining, iron and gas e involved. The investigation is made in four pts where the first one is on the supply of biomass. A lge amount of Biomass has to be delivered into a single site to exchange a lge amount of fossil reductant. Also, forestry by-products should be used as most of the round wood is reserved for other uses. Hvesting, logistics and economics e considered. The second pt is on the gasification of the biomass, where the aim is to use to produce hot gas that can be used directly. Pilot experiments e cried out using oxygen in an entrained flow gasifier. The third pt is on the metallurgical processes, where reduction tests e cried out with gas that can be produced in the gasifier. The limitations of the gas content e studied as well as the effect on DRI. Also the suitability of the DRI product is evaluated. The fourth pt of the project uses process integration to model the whole process chain. The results from the other project pts e used to build the system model. It is then used for technical economic optimization the whole system hvesting- Transport-gasifier-direct reduction-use of DRI. The first use of the system model has been to find the best supply road (hvesting, pretreatment and transport) for a chosen production case The simulations indicated that the supply of residuals is possible but will need material from a lge pt of the north Sweden wood ea, and that a relatively lge amount of gas recirculation is needed. The continuing work is focused on further development of the optimization tool and the use of it for more extensive studies of the trade-off between pameters of metallurgy, gasification and supply. The result can be important for evaluation of future industrial applications. It could also help in understanding the effect of governmental control instruments. The paper will mainly focus on the process integration study.
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| 5. |
- Grip, Carl-Erik, et al.
(författare)
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Forestry meets Steel. A Technoeconomic study of the possible DRI production using biomass
- 2015
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Konferensbidrag (refereegranskat)abstract
- The possibility to produce DRI using gasified Biomass is studied in a cooperative project. LTU, MEFOS, ETC and five industries in the areas forestry & pulp, mining, iron and gas are involved. The production chain Biomass production and distribution -Gasification-DRI production-DRI use is investigated in four work packages:WP1: Biomass supply: A large amount of Biomass has to be delivered into a single site to exchange a large amount of fossil reductant. It is important to use forestry by- products as a major part of round wood is reserved for other uses. Harvesting, logistics and economics have to be considered. Available data were collected and used to make a system model on harvesting treatment and transport. The simulations indicated that the supply of residuals is possible but will need material from a large part of the north Sweden wood area. WP2: Gasification. The aim is to use to produce hot gas that can be used directly. Pilot experiments are carried out using oxygen in an entrained flow gasifier. WP3: Metallurgical processes. Reduction tests are carried out with gas that can be produced in the gasifier. The limitations of the gas content are studied as well as the effect on DRI. Also the suitability of the DRI product is evaluated WP4: Process integration. A system model is built using the results from work packages 1-3 and used for technical economic optimization the whole system harvesting-transport-gasifier-direct reduction- use of DRI. The process chain is technically possible; however there are problems to be solved, e.g., gas quality vs. demands from DRI process, Biomass supply and logistics. The result is important to evaluate for industrial application, but also to get information of the effect of different governmental control instruments.
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| 6. |
- Grip, Carl-Erik, et al.
(författare)
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Industrial ecology in northern areas : practical experience and development
- 2010
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Konferensbidrag (refereegranskat)abstract
- The possibilities to develop the industrial ecology in the northern regions of Europe are influenced by some common characteristics, e.g.: The regions are rich in natural re-sources and energy- and material intensive base industries. These industries cover sev-eral branches, e.g., Mining, Iron and Steel, Metal production, Pulp and Paper. Low popu-lation density and relatively long distances to the main customers are difficulties espe-cially for transport and use of rest products. District heating with waste heat from the in-dustries is an important part of the energy system that reduces the emission of green-house gases and improves the overall energy efficiency. The problems and possibilities connected to the industrial ecology are described for two examples, the energy system in Luleå and the Solander science park in Piteå
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| 7. |
- Grip, Carl-Erik, et al.
(författare)
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Possibilities and problems in using exergy expressions in process integration
- 2011
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Ingår i: Proceedings of the World Renewable Energy Congress 2011 (WREC 2011), 9-13 May, Linköping.. - Linköping : Linköping University Electronic Press. ; , s. 1605-1612
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Konferensbidrag (refereegranskat)abstract
- Industrial energy systems are complicated networks, where changes in one process influence its neighboring processes. Saving energy in one unit does not necessarily lead to energy savings for the total system. A study has been carried out on the possibility to use the exergy concept in the analysis of industrial energy systems. The exergy concept defines the quality of an amount of energy in relation to its surrounding, expressing the part that could be converted into work. The study consists of literature studies and general evaluations, an extensive case study and an interview study. In the latter it was found that non technical factors are major obstacles to the introduction of exergy.
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| 8. |
- Grip, Niklas, et al.
(författare)
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Wavelet study of dynamic variations in steel and ironmaking rest gases. Potential effect on external use
- 2013
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Ingår i: Applied Energy. - : Elsevier BV. - 0306-2619 .- 1872-9118. ; 112, s. 1032-1040
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Tidskriftsartikel (refereegranskat)abstract
- The surplus energy in rest gases is an important by-product in the SSAB EMEA steel plant in Luleå. The surplus is used in a local heat and power plant. Studies have been and are being carried out to find alternative use for the high calorific gases, especially the coke oven gas. The different gas flows typically are mixtures of irregularly distributed transients and non-periodic contents of different duration. Slowly varying fluctuations can probably be parried by good production planning. For shorter wavelengths some kind of safety margin could be appropriate, perhaps in the range 0.75–1.5 kN m3/h. However, the existing buffer capacity in gasholders, etc. is too small to cover the fluctuations. Good production planning can partly compensate low buffer capacity. An example from a period without gas holder is discussed.We describe analysis of the gas flows that can be used both for better production planning and for efficient external use, e.g., for fuel production. Rather than traditional Fourier analysis, we use wavelet analysis, which is better suited for analyzing the irregular and nonperiodic characteristics of the gas flows. We demonstrate such analysis on collected gas flow data from the SSAB EMEA steel plant and give some suggestions for how to make a good choice of wavelet basis for the analyzed signals.
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| 9. |
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| 10. |
- Alriksson, Stina, 1971-
(författare)
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Environmental preferences among steel stakeholders
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Emissions of carbon dioxide, dioxins, nitrogen oxides and particulate matter as well as use of non-renewable resources and energy are some important sustainability challenges for the Swedish steel industry. Much effort has been made, mainly by technical solutions, which to a high degree have decreased the emissions during the last 30 years.Technical solutions however will not be sufficient to reach sustainable development, stakeholder involvement is also necessary. Stakeholder theory states that stakeholder involvement must include a dialog between the stakeholders involved and the operation. The first step in this process is to identify which key issues the stakeholders find most important and then the organisation needs to start interact with its stakeholders. This thesis deals with such issues.Stakeholder preferences for environmental issues were assessed with conjoint analysis, Q-methodology and focus group discussions. The theory of planned behaviour was used to assess how attitudes were connected to background factors and a potential pro-environmental behaviour.Five studies have been carried out in the framework of this thesis. The studies include: a literature review, method evaluation, evaluation of environmental objectives in stakeholder groups, screening of relevant factors, evaluation of steel environmental characteristics, identification of barriers to the introduction of new materials and the impact of worry and risk perception on strategic environmental decisions.It can be concluded that the methods applied in the studies work well in eliciting preferences. It has been possible to show how different stakeholder groups as well as individuals prioritise environmental objectives and sustainability issues. Since individuals within a stakeholder group vary considerably in preferences, the results from this thesis show the importance of illustrating results on an individual level instead of the traditional group level. Also, a method has been tested where the results were brought back to the respondents in order to stimulate discussions between different stakeholder groups.
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