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Fridén, Håkan
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Publications (10 of 24) Show all publications
Björkqvist, O., Engstrand, P. & Fridén, H. (2009). Concepts of Steam Recovery from LC-Refining by Increase Temperature. In: Proceedings - 2009 International Mechanical Pulping Conference, IMPC 2009. Paper presented at 2009 International Mechanical Pulping Conference, IMPC 2009; Sundsvall; 31 May 2009 through 4 June 2009; Code 79937 (pp. 190-194).
Open this publication in new window or tab >>Concepts of Steam Recovery from LC-Refining by Increase Temperature
2009 (English)In: Proceedings - 2009 International Mechanical Pulping Conference, IMPC 2009, 2009, p. 190-194Conference paper, Published paper (Refereed)
Abstract [en]

In a mechanical pulping process, (TMP) wood is refined to pulp in a process with very high wood utilization. However, the power demand in the process is high. Thus efficient energy recovery, especially steam recov-ery, is very important. In high consistency (HC) refining the pulp wood is refined at high temperature (140°C) and pressure. The high temperature makes it possible to recover process heat with usable steam properties.

One strategy to decrease the power consumption is to split the refining into two stages, one HC-stage and one low consistency (LC) refining stage. This kind of sys-tem is quite common today. One drawback with LC-refining is that it operates at a low temperature normally below 100°C. Hence, the steam recovery potential from conventional LC-refining is limited.

In this project, we analyse three concepts of steam re-covery in LC-refining by increasing the temperature in the LC-stage. Two base cases: Conventional HC refin-ing only and conventional HC/LC refining is compared with three steam recovery cases: Pulp/Pulp heat ex-changing, Screw Press Dewatering combined with proc-ess water re-circulation and finally Pulp/Water Heat Exchanging.

The study shows that it is possible to recover steam from the LC-stage and, hence, increase the energy effi-ciency of a combined HC/LC refining system. The screw press case has the highest steam recovery poten-tial of the HC/LC configurations. An initial economic estimate indicates that steam recovery in LC-refining is profitable compared to a conventional HC/LC-configuration.

Keywords
energy efficiency, steam recovery, mechanical pulping.
Identifiers
urn:nbn:se:miun:diva-10192 (URN)2-s2.0-77951099503 (Scopus ID)
Conference
2009 International Mechanical Pulping Conference, IMPC 2009; Sundsvall; 31 May 2009 through 4 June 2009; Code 79937
Available from: 2009-10-29 Created: 2009-10-27 Last updated: 2011-04-06Bibliographically approved
Björkqvist, O., Engstrand, P. & Fridén, H. (2008). Energiåtervinning vid LC-raffinering – Förstudie. Stockholm: Värmeforsk
Open this publication in new window or tab >>Energiåtervinning vid LC-raffinering – Förstudie
2008 (Swedish)Report (Other academic)
Abstract [sv]

Ökade energikostnader och råvarupriser innebär att effektiv energianvändning blir enviktig faktor för att skapa långsiktig konkurrenskraft och utvecklingsförmåga för massaochpappersindustrin. I detta projekt analyseras möjligheten att öka ångåtervinningenfrån en mekanisk massaprocess där raffinering vid hög massakoncentration (HCraffinering)kombineras med raffinering vid låg massakoncentration (LC-raffinering).Vid HC-raffinering finns sedan många år väl utvecklad teknik för att återvinna ånga.Vid konventionell LC-raffinering är det inte möjligt att återvinna ånga eftersom temperaturnivåernaär för låga, lägre än 100°C. Genom att värmeväxla producerad massa ellerpressat från processen kan man öka temperaturen i LC-steget så att det blir möjligt attåtervinna processånga med användbara ångdata, i detta fall 2,7 bar och 130°C.I projektet har tre alternativa konfigurationer för ångåtervinning analyserats(A) Ångåtervinning i kombination med massa/massa värmeväxling (B) Ångåtervinningi kombination med en trycksatt skruvpress och (C) Ångåtervinning i kombination medmassa/vatten värmeväxling.En inledande lönsamhetsberäkning visar att ångåtervinning från LC-steget kan ha enmycket god lönsamhet. Fall B, ångåtervinning i kombination med trycksatt skruvpressvisar bäst potential för fortsatta studier. Det beror på att värmeåtervinningen sker genominblandning av pressat i spädvattnet och värmeväxling av vatten med en konventionellvärmeväxlare. Det innebär att de tekniska riskerna i detta alternativ är låga.Utvecklingen av de värmeväxlare som ingår i fallen A och B och som kan hantera massamed 5% massakoncentration innebär en stor teknisk utmaning och associerad risk.Det finns idag inga sådana växlare på marknaden och det är osäkert om man kan konstrueraen växlare som kan hantera massa med hög viskositet och som har tillräckligthög temperaturverkningsgrad.Projektet har uppfyllt målet att visa att det teoretiskt är energitekniskt möjligt att modifieraen LC-process så att ånga kan återvinnas även från detta steg. Detta innebär enförbättring av den konventionella LC-processens energieffektivitet. Projektets resultatkan vara ett underlag för beslut om fortsatt forskning inom området energieffektiv LCraffinering.

Abstract [en]

Normally, steam recovery from a conventional low consistency (LC) mechanical pulprefining system is not possible. This is due to the fact that the temperature level in theLC-refiner is less than 100°C. The steam with such a low temperature and associatedpressure has limited value in the mill. In this project, we study a concept of increasingthe temperature in the refiner to a level were process steam with higher quality can berecovered. The temperature level can be increased by transferring heat from outgoingpulp or drainage to incoming pulp or water. This makes it possible to recover heat fromthe process.An initial estimate indicates that steam recovery from LC-refining systems may have agood economic potential. Three cases have been analyzed: Case A: Steam recovery incombination with pulp/pulp heat exchanging, Case B: Steam recovery in combinationwith a pressurized screw press and finally Case C: steam recovery in combination withpump/water heat exchanging.Case B show the best specific steam recovery, 87% kWh recovered steam per kWh usedelectricity. This concept has a lower technological uncertainty compared to cases A andC as it does not need heat exchanging from pulp.The specific heat recovery from case A and C is 78% and 82% respectively. However,the suggested heat exchangers used in these cases do not exist on the market today.There is hence a need for development of exchangers that can handle pulp with highviscosity. The technological risk associated with the screw press scenario is lower and itis likely that this concept is easier to implement.

Place, publisher, year, edition, pages
Stockholm: Värmeforsk, 2008. p. 27
Series
Värmeforsk skogsindustriella programmet ; S5-622
Keywords
energy efficiency, steam recovery, mechanical pulping, energieffektivisering, ångåtervinning, mekanisk massa
National Category
Energy Engineering
Identifiers
urn:nbn:se:miun:diva-7996 (URN)
Available from: 2009-01-07 Created: 2009-01-07 Last updated: 2009-06-08Bibliographically approved
Fridén, H., Stattin, A. & Löfgren, G. (2008). Online operator decision support and optimization for sack paper production by PAT based process automation. In: Third pan-European PAT conference: Oct 7-8, Gothenburg, Sweden.
Open this publication in new window or tab >>Online operator decision support and optimization for sack paper production by PAT based process automation
2008 (English)In: Third pan-European PAT conference: Oct 7-8, Gothenburg, Sweden, 2008Conference paper, Published paper (Other academic)
National Category
Paper, Pulp and Fiber Technology Control Engineering
Identifiers
urn:nbn:se:miun:diva-11108 (URN)
Available from: 2010-01-14 Created: 2010-01-14 Last updated: 2011-07-06Bibliographically approved
Fridén, H., Näslund, H., Stattin, A. & Löfgren, G. (2006). Online decision support and optimization for kraft paper production. In: Control systems 2006 : Measurement and control: applications for the operator, Tampere, Finland, 6-8 June 2006: (pp. 313-). Helsinki: Kopio Niini - Painoporssi,
Open this publication in new window or tab >>Online decision support and optimization for kraft paper production
2006 (English)In: Control systems 2006 : Measurement and control: applications for the operator, Tampere, Finland, 6-8 June 2006, Helsinki: Kopio Niini - Painoporssi, , 2006, p. 313-Conference paper, Published paper (Other scientific)
Abstract [en]

The MondiPackaging Dynäs pulp & paper mill in Sweden produces strong sack and kraft paper from chemical softwood pulp. Despite good quality a project was initiated by a need for less variability in paper quality, and less energy consumption. It was known that there is variability in incoming stock, and that the HC and LC refining strategies could be improved. The aim of the project is to reduce energy consumption by 10%, and to reduce quality variation by installing a new online fibre analyzer, PulpEye, and implementing modern modelling and control methodology. We have used multivariate subspace models in combination with optimization to create an OPC based interactive application for on-line operator support and optimization of kraft paper production. The application is now installed and is under evaluation. The specific refiner energy has so far been reduced with at least 25%. The decision support application is indicating even more reduction potential.

Place, publisher, year, edition, pages
Helsinki: Kopio Niini - Painoporssi,, 2006
Keywords
Chemical pulping, Refining, Multivariate modelling, Simulation, Energy control, Quality control, Decision support
National Category
Control Engineering Computer Sciences Probability Theory and Statistics
Identifiers
urn:nbn:se:miun:diva-3798 (URN)4159 (Local ID)9525183262 (ISBN)4159 (Archive number)4159 (OAI)
Available from: 2008-09-30 Created: 2008-11-03 Last updated: 2018-01-12Bibliographically approved
Pavlenko, T. & Fridén, H. (2006). Scoring Feature Subsets for Separation power in Supervised Bayes Classification. Advances in Intelligent and Soft Computing, 37, 383-391
Open this publication in new window or tab >>Scoring Feature Subsets for Separation power in Supervised Bayes Classification
2006 (English)In: Advances in Intelligent and Soft Computing, ISSN 1867-5662, E-ISSN 1867-5670, Vol. 37, p. 383-391Article in journal (Refereed) Published
Abstract [en]

We present a method for evaluating the discriminative power of compact feature combinations (blocks) using the distance-based scoring measure, yielding an algorithm for selecting feature blocks that significantly contribute to the outcome variation. To estimate classification performance with subset selection in a high dimensional framework we jointly evaluate both stages of the process: selection of significantly relevant blocks and classification. Classification power and performance properties of the classifier with the proposed subset selection technique has been studied on several simulation models and confirms the benefit of this approach.

Place, publisher, year, edition, pages
Berlin: Springer, 2006
Keywords
multivariate statistics, classification
National Category
Mathematics
Identifiers
urn:nbn:se:miun:diva-3867 (URN)10.1007/3-540-34777-1_45 (DOI)2-s2.0-58149242746 (Scopus ID)4162 (Local ID)978-3-540-34776-7 (ISBN)4162 (Archive number)4162 (OAI)
Available from: 2008-09-30 Created: 2008-09-30 Last updated: 2017-12-12Bibliographically approved
Fridén, H. (2005). Model based process monitoring, control and optimization in real time: ÅF:s Automationsdagar 2005.
Open this publication in new window or tab >>Model based process monitoring, control and optimization in real time: ÅF:s Automationsdagar 2005
2005 (English)Conference paper, Published paper (Other academic)
Keywords
processmodellering
National Category
Economics and Business
Identifiers
urn:nbn:se:miun:diva-1097 (URN)3545 (Local ID)3545 (Archive number)3545 (OAI)
Available from: 2008-09-30 Created: 2008-09-30 Last updated: 2011-04-06Bibliographically approved
Fridén, H. & Tano, K. (2005). Using PLS models with both controlled and uncontrolled X variables for "Waht if..." prediction. In: The 9th Scandinavian Symposium on Chemometrics, Reykjavik, Iceland 2005-09-30 (pp. 6-). Ornsköldsvik: NPI
Open this publication in new window or tab >>Using PLS models with both controlled and uncontrolled X variables for "Waht if..." prediction
2005 (English)In: The 9th Scandinavian Symposium on Chemometrics, Reykjavik, Iceland 2005-09-30, Ornsköldsvik: NPI , 2005, p. 6-Conference paper, Published paper (Other scientific)
Abstract [en]

In real-time industrial process applications, there is often a need to predict the effects of adjustments before actually effectuated. Multivariate prediction models based on historical data works fine for predictions as long as the new X data have the correlation structure preserved. This paper shows that such can anyway be used for �What if �� decision support in presence of correlated X variables, whenever it is possible to create a help model that predicts the influence of the manipulated X variables on the rest of the X variables.

Place, publisher, year, edition, pages
Ornsköldsvik: NPI, 2005
Keywords
algorithm PLS process predictions
National Category
Control Engineering Computer Sciences Probability Theory and Statistics
Identifiers
urn:nbn:se:miun:diva-3464 (URN)3544 (Local ID)3544 (Archive number)3544 (OAI)
Available from: 2008-09-30 Created: 2008-09-30 Last updated: 2018-01-12Bibliographically approved
Fridén, H. (2005). Virtual Control Room (VCR) : NPI - Project Report Sep 2005. Örnsköldsvik: Network for Process Intelligence • Mitthögskolan
Open this publication in new window or tab >>Virtual Control Room (VCR) : NPI - Project Report Sep 2005
2005 (English)Book (Other scientific)
Place, publisher, year, edition, pages
Örnsköldsvik: Network for Process Intelligence • Mitthögskolan, 2005. p. 21
Keywords
Process modellering OPC simulering övervakning
National Category
Control Engineering Computer Sciences Probability Theory and Statistics
Identifiers
urn:nbn:se:miun:diva-3465 (URN)3546 (Local ID)3546 (Archive number)3546 (OAI)
Available from: 2008-09-30 Created: 2008-09-30 Last updated: 2018-01-12Bibliographically approved
Fridén, H. (2004). Process modelling - a future part in an operator's guide: Automatiseringsdagarna 2004 in Storlien.
Open this publication in new window or tab >>Process modelling - a future part in an operator's guide: Automatiseringsdagarna 2004 in Storlien
2004 (English)Conference paper, Published paper (Other scientific)
Keywords
Process intelligence
National Category
Mathematics Control Engineering
Identifiers
urn:nbn:se:miun:diva-1000 (URN)2248 (Local ID)2248 (Archive number)2248 (OAI)
Available from: 2008-09-30 Created: 2008-09-30Bibliographically approved
Fridén, H. (2004). Process modelling - a future part in an operators guide.: The FlowMac Conference year 2004, Kolmården, June 15-16.
Open this publication in new window or tab >>Process modelling - a future part in an operators guide.: The FlowMac Conference year 2004, Kolmården, June 15-16
2004 (English)Conference paper, Published paper (Other scientific)
Keywords
process modelling simulation
National Category
Computer Sciences Probability Theory and Statistics Control Engineering
Identifiers
urn:nbn:se:miun:diva-1082 (URN)2983 (Local ID)2983 (Archive number)2983 (OAI)
Available from: 2008-09-30 Created: 2008-09-30 Last updated: 2018-01-13Bibliographically approved
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