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| 2. |
- Andersson, Eva Ingeborg Elisabeth, 1956, et al.
(författare)
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TSA II Stenungsund - Investigation of opportunities for implementation of proposed energy efficiency measures
- 2011
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- A Total Site Analysis (TSA) study of the chemical cluster in Stenungsund was conducted during 2010. This previous study is hereafter referred to as the TSA I study. The study was conducted by CIT Industriell Energi and the Division of Heat and Power Technology at Chalmers together with the participating cluster companies (AGA Gas AB, Akzo Nobel Sverige AB, Borealis AB, INEOS Sverige AB and Perstorp Oxo AB).In the TSA I study, measures to increase energy efficiency by increased energy collaboration (i.e. increased heat exchange between the cluster plants) were identified. The measures were classified according to ease of implementation based on consultation with plant staff. In this report, conducted within the framework of the second stage of the TSA research project (hereafter referred to as the TSA II project) practical issues associated with implementation of the identified measures are investigated. The investigation is limited to category A measures, considered by plant staff to be relatively easy to implement from a technical perspective. A conceptual design of a possible hot water system for exchanging heat between the different sites is presented. Since the steam systems of the different plants are at present only partly connected, or not at all, the overall reduction in steam use that would results from introduction of a hot water system would lead to steam surplus at certain sites. Therefore introducing a hot water system is only beneficial if new steam lines are also implemented so that it becomes possible to exchange steam between the individual plant sites. The exchange of steam is only possible if steam demand and steam excess are at the same pressure level. To avoid excess steam at low pressure level, demand of low pressure steam must increase. In order to increase the possibility to use more low pressure steam, the opportunities to decrease utility steam pressure in individual process heaters are analyzed. The implementation of energy efficiency measures in the refrigeration systems is also investigated. In practice this can be achieved by changing steam as heating utility to a fluid that can operate below ambient. In addition to the steam saving, the heat transfer fluid can transport energy from the current cooling systems and decrease the amount of compressor work required to operate the existing refrigeration system units.In order to achieve a reduction of purchased fuel for firing in boilers it is necessary to implement both a common site-wide circulating hot water system and a reduction of utility steam pressure used in several process heaters .The results show that if all measures that are considered by plant energy engineers to be feasible by moderate changes are carried out as suggested, fuel usage in boilers could be reduced by 89 MW (corresponding to 200 MSEK/year if fuel gas is valued at 270 SEK/MWh and year-round operation is assumed).A rough estimate of the total investment costs for the implementation of category A measures is 660 MSEK.
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| 3. |
- Andersson, Viktor, 1983, et al.
(författare)
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Dubbel energivinst med alger som biobränsle
- 2013
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Ingår i: Energimagasinet.
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Idag kan produktionen av biobränsle påverka livsmedelsförsörjningen negativt. Istället för att biobränsleproduktion ska konkurrera med produktion av livsmedel kan en hittills outnyttjad resurs - kommunalt avloppsvatten - användas för produktion av alger som i sin tur kan användas till biogas och biodiesel. Ny forskning visar på denna potential.
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| 4. |
- Broberg, Sarah, 1983-, et al.
(författare)
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Integrated Algae Cultivation for Biofuels Production in Industrial Clusters
- 2011
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Declining fossil resources and the issue of climate change caused by anthropogenic emissions of greenhouse gases make global action towards a more sustainable society inevitable. The EU decided in 2007 that 20 % of the union´s energy use should origin from renewable resources by the year 2020. One way of achieving this goal is to increase the utilisation of biofuels. Today 2nd generation biofuels are being developed. They are seen as a more sustainable solution than 1st generation biofuels since they have a higher area efficiency (more fuel produced per area) and the biomass can be cultivated at land which is not suitable for food crops. One of these 2nd generation biofuels are fuels derived from microalgae. In this study a thorough literature survey has been conducted in order to assess the State-of-the-Art in algae biofuels production. The literature review showed the importance of a supplementary function in conjunction with algae cultivation and therefore algae cultivation for municipal wastewater treatment and capturing CO2 emissions from industry was included in the study. It was assumed that all the wastewater of the city of Gothenburg, Sweden, was treated by algae cultivation. A computer model of the whole production process has been developed, covering; algae cultivation in conjunction with wastewater treatment, algae harvesting and biofuels production. Two different cases are modelled; a first case including combined biodiesel and biogas production, and a second case investigating only biogas production. Both cases have been evaluated in terms of product outputs, CO2 emissions savings and compared to each other in an economic sense. Utilising the nutrients in the wastewater of Gothenburg it is possible to cultivate 29 ktalgae/year. In the biogas case it is possible to produce 205 GWhbiogas/year. The biogas/biodiesel case showed a production potential of 63 GWhbiodiesel/year and 182 GWhbiogas/year. There is a deficit of carbon in the wastewater, hence CO2 is injected as flue gases from industrial sources. The biodiesel/biogas case showed an industrial CO2 sequestration capacity of 24 ktCO2/year while in the biogas case 22.6 ktCO2/year, could be captured. Estimating the total CO2 emissions savings showed 46 ktCO2/year in the biodiesel/biogas case and 38 ktCO2/year for the biogas case. The importance of including wastewater treatment in the process was confirmed, as it contributes with 13.7 ktCO2/year to the total CO2 emissions savings. Economic comparison of the two cases showed that biodiesel in conjunction with biogas production is advantageous compared to only biogas production. This is mainly due to the higher overall fuel yield and the high willingness to pay for biodiesel. The total incomes from biodiesel/biogas sales were calculated to 221 million SEK/year and 193 million SEK/year for biogas. It was found that the higher incomes from biodiesel/biogas sales repay the increased investment for the biodiesel process in approximately 3 years.
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| 5. |
- Grahn, Maria, 1963, et al.
(författare)
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The role of electrofuels: A cost-effective solution for future transport?
- 2017
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Electrofuels (also known as e.g., power-to-gas/liquids/fuels, e-fuels, or synthetic fuels) are synthetichydrocarbons, e.g. methane or methanol, produced from carbon dioxide (CO2) and water with electricity as primary energy source. The CO2 can be captured from various industrial processes giving rise to excess CO2 e.g. biofuel production plants, and fossil and biomass combustionplants. Electrofuels are interesting at least for the following reasons: (i) electrofuels may play an importantrole as transport fuels in the future due to limitations with other options and are potentially of interestfor all transport modes, (ii) electrofuels could be used to store intermittent electricity production,and (iii) electrofuels potentially provide an opportunity for biofuel producers to increase the yield from the same amount of biomass. The overall purpose of this project is to deepen the knowledge of electrofuels by mapping andanalyzing the technical and economic potential and by analyzing the potential role of electrofuels inthe future energy system aiming to reach stringent climate targets. The specific project targets include:(i) Mapping of the technical potential for CO2-recovering from Swedish production plants forbiofuels for transport and combustion plants.(ii) A review and analysis of different electrofuel production pathways and associated costsand an overall comparison with the production cost of other renewable transport fuels.(iii) An analysis of the potential conditions under which electrofuels are cost-effective comparedto other alternative fuels for transport in order to reach stringent climate targets. Main conclusions are: (1)Electrofuels used in combustion engines demand significantly more energy compared tobattery electric vehicles and hydrogen used in fuel cells, (2) Compared to biofuels, our estimates of the production costs of electrofuels are in the samesize of order but in the upper range or above, (3) The results of the energy system modelling indicate that electrofuels is not the most costefficientoption for road transport. Thus, it is not likely that electrofuels can compete withcurrent conventional fuels in road transportation (unless there are higher taxes on fossilCO2-emissions), (4) Under some circumstances (e.g., when assuming relatively high costs for other options),electrofuels may be able to complement battery electric vehicles and hydrogen used in fuelcells in a scenario reaching almost zero CO2 emissions in the global road transport sector, (5) The cost-competitiveness of electrofuels depends on e.g. the availability of advanced CO2reduction technologies such as CCS, and costs for the competing technologies, but also onthe costs and efficiencies of synthesis reactors and electrolysers for the electrofuel productionas well as the electricity price, (6) In the short term, renewable CO2 does not seem to be a limiting factor for electrofuels.However, the demand for renewable electricity represents a possible limiting factor especiallyin the case of large-scale production of electrofuels. The production cost may alsorepresent a challenge.
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| 6. |
- Hackl, Roman, 1981
(författare)
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A Methodology for Identifying Transformation Pathways for Industrial Process Clusters: Toward Increased Energy Efficiency and Renewable Feedstock
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The European process industry is facing major challenges. Modern, large-scale production facilities in other parts of the world are often more efficient. Furthermore, limited access to inexpensive shale gas from North America has led to an additional disadvantage for the European industry. At the same time, the European Union (EU) has implemented policy instruments aiming at increasing the costs for emitting Greenhouse Gases (GHG) in order to curb global warming.According to the International Energy Agency (IEA), the only measure that decreases GHG emissions and at the same time achieves economic, environmental and societal goals is increasing energy efficiency. Clusters of industrial production plants often offer considerable opportunities to increase efficiency at the total site level. Another option for the process industry is to tap into new markets in order to stay competitive. The interest for biomass based products has increased lately due to societal expectations for sustainable development and renewable feedstock based products. This work presents a framework methodology that can provide guidance to the process industry in order to manage this transformation in an efficient way. Process integration tools are used to identify common measures to improve energy efficiency at a site-wide scale. This targeting procedure is followed by a detailed procedure for design and evaluation of practical energy efficiency measures. This step should be performed in close collaboration with experts from the industrial cluster in order to present solutions that can overcome some of the main barriers for the implementation of common energy efficiency measures. The knowledge obtained during this targeting and design process can also be used to identify favourable ways to integrate biomass based processes that can replace fossil with biogenic feedstocks and utilise existing infrastructure. In most chemical processes, there is usually excess process heat that cannot be utilised internally. In the last stage of the framework methodology developed in this work, the opportunity to export industrial excess heat should be investigated. This includes an assessment of the quantity of available heat, the economic feasibility and the competition between internal integration and the export of heat.The framework methodology is demonstrated via a case study of a chemical cluster in Sweden.
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| 7. |
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| 8. |
- Hackl, Roman, 1981, et al.
(författare)
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Identification, cost estimation and economic performance of common heat recovery systems for the chemical cluster in Stenungsund
- 2013
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- In previous work, the heat savings potential that can be accomplished by increased heat recovery collaboration between the constituent companies was identified at the chemical cluster in Stenungsund. Based on this work specific measures to realize the potential were determined. All heat exchangers that can be included in a common heat recovery system were identified and other measures necessary in order to construct such a system were described. Detailed systems design, cost estimation, economic evaluation and cost sensitivity analysis was not dealt with in detail. A number of different systems solutions are available In order to identify cost-efficient system configurations it is important to develop a methodology that deals with design, cost estimation, economic evaluation and cost sensitivity analysis. The present study aims the development of such a methodology in order to enable decision makers to identify and compare cost-efficient and site-wide common heat recovery system configurations.In a first step all the different cost items of the common heat recovery measures are identified. After that a short cut approach for estimating the different costs (HX, piping, pumps etc.) involved is applied. Later a methodological approach to identify the most cost efficient overall systems solutions is introduced. During this a number of promising options is identified, which then are evaluated in more detail according their economic performance.As a result five promising systems were identified saving between 20.6 MW and 53.6 MW of hot utility. The estimated Pay Back Period (PBP) of the system was between 3.2 and 4.2 years. Further evaluation showed that especially two systems showed superior economic performance. System 20 recovering 20.6 MW of heat at a PBP of 3.2 years has the best Discounted Cash Flow Rate Of Return (DCFROR) of all systems (34.2 %). The retrofit only involves Borealis and Perstorp. Perstorp only serves as a sink for excess LP steam from Borealis, while recovered excess process heat is delivered from Borealis PE to Borealis Cracker. As it only enables for utilizing a minor share of the total heat integration potential it is considered as a first step towards a larger system. The final step in the development of common heat recovery systems is System 50 recovering 50.8 MW of heat at a PBP of 3.9 years and a DCFROR of 26.6 %. This system shows the highest Net Present Value of all investigated systems and recovers a major share of the heat recovery potential. Three companies, Borealis, Perstorp and INEOS are involved in the retrofit. Borealis PE and Perstorp are mainly delivering excess process heat to Borealis Cracker, while INEOS solely servers as a sink for excess steam from Borealis Cracker. It is possible to extend System 20 towards System 50 if minor preparatory investments are taken. Sensitivity analysis showed that only in two scenarios where the price of saved fuel decrease or the total investment costs increase by 30 % the PBP of System 50 exceeds 5 years and DCFROR drops below 20 %. The systems identified can be considered robust to fluctuations in investments costs and fuel price.The methodology applied in this study was shown to enable for identifying cost efficient and economically robust heat recovery systems and even making it possible to describe staged investment paths where the simplest investments are taken first allowing for further systems extension in order to realize the a larger share of the heat recovery potential.
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| 9. |
- Hackl, Roman, 1981, et al.
(författare)
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Opportunities for Process Integrated Biorefinery Concepts in the Chemical Cluster in Stenungsund
- 2010
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The energy and material needs of human society are increasing while at the same time fossil resources decline. Greenhouse gas (GHG) emissions are influencing the world’s climate. The potential for substituting fossil hydrocarbons in synthetic products and liquid fuels by renewable raw materials is being discussed in order to fight climate change and decrease dependency on fossil resources. The biorefinery concept is a way to accomplish this transition. A wide range of renewable raw materials can be converted into value added products and therefore substitute fossil feedstocks. High efficiency is very important in order to profitably implement biorefinery concepts. The interest for energy combines and eco-industrial parks is increasing nowadays as they offer the opportunity to exchange materials and energy between two or more industries and also the society. Therefore integration of biorefinery concepts into industrial cluster can be advantageous. In this study suitable biorefinery concepts are identified and analysed with respect to integration opportunities in Sweden’s largest chemical cluster in Stenungsund. Technical, economical and environmental consequences of integrating a biorefinery in the cluster compared to stand-alone operation are identified based on mass and energy balances, knowledge on the current energy situation in the cluster and the thermal characteristics of the different biorefineries. Suitable biorefinery concepts for integration in the cluster include biomass gasification for syngas production, lignocellulosic ethanol production for conversion into ethylene and low temperature biomass drying for fuel upgrading. The current demand of steam produced in the cluster’s boilers is 122 MW at pressure levels between 85 and 1 bar(g). Excess steam from a gasification unit with an assumed operation time of 8000 h/yr can be used for cogeneration to cover parts of this demand. By integration of a gasification unit producing 160 kt_product gas/yr, 16 GWhel/yr and 128 GWhsteam/yr can be delivered to the cluster. For a stand-alone unit it is assumed that all excess steam is used for electricity production in a condensing turbine, producing 47.4 GWhel/yr. This results in increased incomes between 18.3 and 47.4 MSEK/yr in the integrated case. CO2 emissions reduction is 24.4 kt_CO2/yr higher with integration.Ethanol production from lignocellulosic raw material yields substantial amounts of residual products which can be used for heat and power generation to cover parts of the clusters current energy demand and/or deliver heat and electricity to a downstream ethanol-to-ethylene dehydration plant. The results are obtained for a process that produces 100 kt ethylene/yr and has an operating time of 8000 h/yr. A lignocellulosic ethanol plant producing the feedstock (174 kt ethanol/yr) to an ethanol-to-ethylene plant has an energy surplus of 195.2 GWh/yr when all residues are combusted. In an integrated plant this yields 21.8 GWhel/yr and 168 GWhsteam/yr to the cluster and/or the ethanol-to-ethylene plant, while in stand-alone operation (only production of electricity from excess steam) 64.3 GWhel/yr can be produced. Incomes by integration are between 24.8 and 64.2 MSEK/yr higher and CO2 emissions reduction is increased by 31.2 kt/yr by integration.An improved utility system for maximum energy recovery was developed in a previous total site analysis (TSA) study. The residual waste heat is 498 MW at 99 °C to 27 °C. Utilising this heat for low temperature drying of biomass was compared to stand-alone dryer operation. This gave a total potential of 4.3*106 tonnes dried biomass per year (15 wt-% moisture content). By integration 129 SEK/t_dry mass less fuel costs and 234 kg/t_dry mass less CO2 emissions where found.
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| 10. |
- Hackl, Roman, 1981, et al.
(författare)
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Total Site Analysis (TSA) Stenungsund
- 2010
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This project was carried out in cooperation between the Division of Heat and Power Technology at Chalmers University of Technology, CIT Industriell Energianalys AB, AGA Gas AB, Akzo Nobel Sverige AB, Borealis AB, INEOS Sverige AB and Perstorp Oxo AB.A Total Site Analysis (TSA) was performed in this study which can be used as a basis for future implementations of energy system integration at the chemical cluster in Stenungsund.At first stream data (Tstart, Ttarget, Q) and data on overall utility consumption of all the processes in the cluster was collected. The analysis is based on data collected on process streams heated or cooled with utility exceeding a heat load of 300 kW. Additionally steam from by-product incineration which cannot be utilised in another way is considered as process heat. With this data the current energy system was analysed by determining steam excess and deficit at each steam level and company. After that, the data was represented in curves, the so called total site profiles (TSP) and the total site composite curves (TSC). The curves were used to determine the site pinch (the limiting factor for further integration) and to identify measures to increase heat recovery. The measures found by TSA were assessed qualitatively with respect to feasibility to determine the most attractive measures. Finally the site wide potential for cogeneration and measures for reduction of external cooling demand below ambient temperature was analysed.Main findings are presented in the following:From the stream data collected is can be seen that the total demand of hot and cold utility of the cluster is 442 MW and 953 MW respectively.By-products, which have to be incinerated on-site provide 40 MW of steam. To cover the external heat demand additional 122 MW of heat is supplied by steam/hot oil from boilers or directly by flue gas from added fuels purchased or available on site. The TSP and TSC curves show a site pinch at the 2 bar(g) steam system (132 °C). The site pinch limits the potential for heat integration. To increase energy savings by heat integration it is necessary to change the position of the site pinch. It was shown that theoretically by introducing a site-wide hot water circuit, increased recovery of 2 bar(g) steam and adjustment steam levels in several heat exchangers the pinch point can be moved so that hot utility savings of 122 MW plus excess of 7 MW steam at 85 bar(g) can be realised.Only introducing a hot water circuit can save 51 MW of steam from added fuels, which corresponds to estimated savings of 122 MSEK/year. It is possible to replace more steam by hot water, but the demand for 2 bar(g) steam is limited. Therefore a demand for low pressure steam must be created by adjusting steam levels in order to utilise more waste heat in a hot water circuit. The present delivery of heat to the district heating system is not affected by a site wide hot water circuit.There is potential for increased recovery of 33 MW of 2 bar(g) steam from process heat. This would replace the production of the same amount of steam in the boilers, worth 79 MSEK/year.A qualitative assessment on the implementation of a hot water circuit shows estimated steam savings of 55.2 MW (132 MSEK/year) with moderate changes (83.5 MW including more complex changes, 200 MSEK/year). Technically the introduction of a hot water circuit includes hot water pipes between several plants, as most of the consumers of heat are situated at the cracker site and at Perstorp but the sources are spread out across the cluster. Also piping is necessary to transfer the 2 bar(g) steam replaced by hot water to other plants with steam deficit.The practical potential for increased 2 bar(g) steam recovery is estimated to 4.2 MW (10 MSEK/year) with moderate changes and 26.6 MW including more complex changes (64 MSEK/year). Increased 2 bar(g) recovery implies the construction of steam pipes from Borealis to Perstorp and INEOS, as most of the potential steam sources are located at Borealis but Perstorp and INEOS have a demand for 2 bar(g) steam The theoretical cogeneration potential in the cluster is 19 MWel in addition to the 10 MWel generated today (additional revenue is 40 MSEK/year) assuming that steam demand at all pressure levels remains the same but the steam systems are connected with each other. A practical option to increase cogeneration with the existing equipment is to supply steam below 8.8 bar(g) produced at Borealis to INEOS, Akzo and Perstorp. This would result in additional 8.6 MWel by cogeneration in Borealis turbo-alternator (estimated revenue: 18 MSEK/year).Some process streams below ambient temperature are heated with steam. It has been shown that 6.5 MW steam is used for heating stream well below ambient temperature. This steam can be saved and the cooling energy can be recovered. This decreases the energy usage in the cooling system and also saves heating steam. Savings up to 48 MSEK/year were estimated.It has been shown that by site wide collaboration it is possible to increase heat recovery, cogeneration and utilisation of waste heat. The results from this study are the bases to identify concrete projects which contribute to cost and CO2 emissions savings. The study also shows the advantages of TSA in order to find solutions for process integration by the utility system on a site wide level.
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