| 1. |
- Danvind, Jonas, et al.
(author)
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Calibration of a constitutive model for diffusive moisture transport in wood using data from X-ray CT-scanning and digital speckle photography
- 2004
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In: 5th Conference on Timber drying for value-added prducts, COST action E15 "advances in drying of wood". ; , s. 210-218
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Conference paper (other academic/artistic)abstract
- An unsteady-state diffusion model is applied for studying wood drying below the fibre saturation point. The moisture diffusion coefficient in Fick's law for Norway spruce under isothermal drying conditions is determined. Using X-ray CT-scanning and Digital Speckle Photography, the wood density and moisture content are obtained in the radial direction of the wood samples. An optimization scheme is used to minimize the difference between observed and computed moisture content in order to calibrate the values of a set of parameters describing the diffusion coefficient. In this study the values of the parameters for a parameterization of Arrhenius' type are determined. The general idea discussed, however, is not limited to a specific model, butcan be used for a wide class of parameter identification problems. The results show a good agreement between observed and computed moisture content and it is concluded that the numerical realization of the optimization scheme works well. Nevertheless, the value of the diffusion coefficient is somewhat higher than expected. This is likely the consequence of a permeable coating of the samples.
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| 2. |
- Eriksson, Håkan, 1973, et al.
(author)
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Black liquor gasification - consequences for both industry and society
- 2004
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In: Energy. - : Elsevier BV. - 0360-5442 .- 1873-6785. ; 29:4, s. 581-612
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Journal article (peer-reviewed)abstract
- The pulp and paper industry consumes large quantities of biofuels to satisfy process requirements. Biomass is however a limited resource, to be used as effectively as possible. Modern pulping operations have excess internal fuels compared to the amounts needed to satisfy process steam demands. The excess fuel is often used for cogeneration of electric power. If market biofuel availability at a reasonable price is limited, import/export to/from a mill however changes the amount of such biofuel available for alternative users. This work compares different mill powerhouse technologies and CHP plant configurations (including conventional recovery boiler technology and black liquor gasification technology) with respect to electric power output from a given fuel resource. Different process steam demand levels for different representative mill types are considered. The comparison accounts for decreased/increased electricity production in an alternative energy system when biofuel is imported/exported to/from the mill. The results show that black liquor gasification is in all cases considered an attractive powerhouse recovery cycle technology. For moderate values of the marginal electric power generation effciency for biofuel exported to the reference alternative energy system, excess mill internal biofuel should be used on mill site for gas turbine based CHP power generation. The remaining excess biofuels in market pulp mills should be exported and used in the reference alternative energy system in this case. For integrated pulp and paper mills, biofuel should be imported, but only for cogeneration usage (i.e. condensing power units should be avoided). If biofuel can be used elsewhere for high effciency CHP power generation, mill internal biofuel should be used exclusively for process heating, and the remainder should be exported.
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| 3. |
- Eriksson, Henrik, 1973, et al.
(author)
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Effects of In-Company Quality Awards on Organizational Performance
- 2003
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In: Total quality management (Print). - : Informa UK Limited. - 0954-4127 .- 1360-0613. ; 14:2, s. 235-242
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Journal article (peer-reviewed)abstract
- The relationship between total quality management (TQM) practices and improved performance has been frequently discussed in the literature. In this paper, the costs and the effects of in-company quality awards on performance are discussed and analysed. The paper covers a survey of Swedish companies that use or have used in-company quality awards to stimulate TQM efforts and thereby to improve performance. The study cannot show any strong evidence of improved performance for units that applied for the in-company quality award. However, in contrast to units that have not applied, some units that have applied for the in-company quality award considered that the results related to performance have improved greatly. One large positive effect perceived by the participating units was increased customer orientation while the largest costs were put on the description of activities and the improvement work itself.
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| 4. |
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| 5. |
- Eriksson, Håkan, 1973, et al.
(author)
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Efficient use of biomass in black liquor gasification plants
- 2001
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In: The International Recovery Conference, Whistler, Canada, Juni 11-14, 2001. Published in the Conference Poster Presentation proceedings. - 1404-7098. ; , s. 75-80
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Conference paper (peer-reviewed)abstract
- The use of biomass in black liquor gasification (BLG) plants was discussed. The configurations with a high electricity output and a high total efficiency based on pulp mills incoming biomass stream were identified. The excess available biofuel was assumed to be exported for use in a direct heating system that replaces natural gas that could be used in a high efficiency combined cycle power plant. The on-site biofuel usage should be limited to the amount needed for back-pressure steam production to cover the mill's heat load.
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| 6. |
- Eriksson, Håkan, 1973, et al.
(author)
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Potential for increased electricity production at an integrated pulp and paper mill with black liquor gasification
- 2001
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In: Proceedings of the 2001 TAPPI Engineering/Finishing and Converting Conference and Trade Fair, San Antonio, 16-20 September 2001. - 1930657838 ; , s. 411-426
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Conference paper (peer-reviewed)abstract
- A number of ongoing efforts aim at reducing greenhouse gas emissions from industrial energy systems. This can be achieved through increased biofuel usage. Biofuels are however a limited resource, and their usage must therefore be as efficient as possible. The objective of this study was to identify pulp and paper mill powerhouse configurations with maximal electricity production from a given limited amount of biofuel (black liquor and conventional wood fuels). The configurations investigated include black liquor gasification and conventional Tomlinson recovery boiler systems. The study is based upon a detailed model of the mill's chemical recovery island and a simplified model of the remainder of the mill. In order to satisfy the mill's heat balance, extra biofuel must be imported for most of the configurations considered. The configuration with the highest on-site electricity production (96 MW) includes biofuel gasification and firing in a gas turbine combined cycle unit. However, if biofuel is assumed a limited resource, importing biomass to the mill implies that less biofuel is available for other competing users. The net global electric power production is shown to decrease from 96 MW to 41 MW for the same powerhouse configuration when performance is evaluated in a global perspective.
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| 7. |
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| 8. |
- Eriksson, Håkan, 1973
(author)
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System Aspects of Black Liquor Gasification – Consequences for both Industry and Society
- 2001
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Licentiate thesis (other academic/artistic)abstract
- The pulp and paper industry consumes large quantities of biofuels (mainly bark and black liquor) to satisfy process requirements. Biomass is however a limited resource, and biofuel usage should therefore be as effective as possible. Modern pulp mills and integrated pulp and paper mills have excess fuel compared to the amounts needed to satisfy the process steam demand. The excess fuel is often used for cogeneration of electric power in CHP units. For integrated pulp and paper mills, this usually requires import of supplementary fuel to the plant. For market pulp mills, the excess internal biofuel quantities are sufficient to also allow electric power generation in condensing power plant units. If biofuel availability at a reasonable price is limited, import/export to/from a mill changes the amount of such biofuel available to alternative users. The goal of this thesis is to compare different mill powerhouse technologies and CHP plant configurations (including conventional recovery boiler technology and black liquor gasification technology) in order to identify the technology and CHP plant configuration that can produce the most electric power output from a given fuel resource for a given process steam demand. Different process steam demand levels for different representative mill types are considered. The comparison accounts for increased/decreased electricity production in an alternative energy system when biofuel is imported/exported to/from the mill. The alternative energy system considered includes a district heating system with CHP capacity and natural gas fired combined cycle power plant capacity. The results show that black liquor gasification is in all cases considered an attractive powerhouse recovery cycle technology compared to conventional recovery boiler technology. If the marginal electric power generation efficiency for biofuel exported to the reference alternative energy system is 49%, excess mill internal biofuel should be used on mill-site for gas turbine based CHP power generation. The remaining excess biofuels in market pulp mills should be exported and used in the reference alternative energy system in this case. For integrated pulp and paper mills, biofuel should be imported, but only for cogeneration usage (i.e. condensing power units should be avoided). If biofuel can be used elsewhere for high efficiency CHP power generation (i.e. a marginal electric power generation efficiency close to 100%), mill internal biofuel should be used exclusively for process heating, and the remainder should be exported for use elsewhere. The thesis also includes an assessment of the potential for increased electricity generation in Sweden if black liquor gasification is systematically implemented in the pulp and paper industry. The assessment accounts for biofuel import/export to/from the mill from/to an alternative energy system consisting of a district heating system with CHP capacity and natural gas combined cycle condensing power plant capacity. Biofuel usage in the reference alternative energy system must also aim to maximise total electric power generation from a given fuel resource. Under these conditions, it is shown that the annual increase in total electricity production resulting from implementation of high performance black liquor gasification technology in the Swedish pulp and paper industry and adapting the reference alternative energy system accordingly could amount at the most to 21 TWh/year. This can be compared to the current on-site production of 3 TWh/year in the pulp and paper industry. Current pulp mills and pulp and paper mills both import biofuel. If decreased electricity production elsewhere as a result of biofuel import is accounted for, the current total electricity production is in fact negative.
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