Change search
Link to record
Permanent link

Direct link
BETA
Germgård, Ulf
Alternative names
Publications (10 of 171) Show all publications
Deshpande, R., Germgård, U., Grundberg, H., Sundvall, L., Giummarella, N., Henriksson, G. & Lawoko, M. (2018). The Reactivity of Lignin Carbohydrate Complex (LCC) During Manufacture of Dissolving Sulphite Pulp from Softwood. Industrial crops and products (Print), 315-322
Open this publication in new window or tab >>The Reactivity of Lignin Carbohydrate Complex (LCC) During Manufacture of Dissolving Sulphite Pulp from Softwood
Show others...
2018 (English)In: Industrial crops and products (Print), ISSN 0926-6690, E-ISSN 1872-633X, p. 315-322Article in journal (Refereed) Published
Place, publisher, year, edition, pages
Elsevier, 2018
Keywords
Lignin carbohydrate complexes, pine heartwood, acid sulfite pulping, two-stage sulfite pulping, covalent bonds
National Category
Chemical Engineering
Research subject
Chemistry; Chemical Engineering
Identifiers
urn:nbn:se:kau:diva-46925 (URN)10.1016/j.indcrop.2018.02.038 (DOI)000428824100037 ()
Funder
Domsjö FabrikerKnowledge FoundationMoRe ResearchKnut and Alice Wallenberg FoundationThe Kempe Foundations
Available from: 2016-10-24 Created: 2016-10-24 Last updated: 2018-09-06Bibliographically approved
Andersson, N., Wilke, C. & Germgård, U. (2017). Impact of dissolved lignin in peroxide bleaching. In: PEERS Conference 2017: Maximizing Success Through Innovation. Paper presented at PEERS Conference 2017: Maximizing Success Through Innovation, 5 November 2017 through 8 November 2017 (pp. 597-604). TAPPI Press
Open this publication in new window or tab >>Impact of dissolved lignin in peroxide bleaching
2017 (English)In: PEERS Conference 2017: Maximizing Success Through Innovation, TAPPI Press , 2017, p. 597-604Conference paper, Published paper (Refereed)
Abstract [en]

It has been demonstrated in previous studies that dissolved lignin carryover has a significant impact in oxygen delignification and chlorine dioxide stages. Specifically for chlorine dioxide stages, it has been shown that the total kappa number of the pulp, i.e. the sum of the fiber kappa number and the filtrate kappa number, corresponds very well to its bleach demand and should be used for accurate feedforward based control. Since peroxide also is commonly used for pulp bleaching, and gaining in popularity, the present study was conducted in order to investigate the basic relations and mechanisms, using laboratory peroxide bleaching experiments comparing different carryover lignin concentrations and types. The results show that in particular chlorine dioxide filtrates have significant negative impact on delignification and brightening, likely due to alkali consumption of e.g. dissolved lignin, and that compensation using a higher alkali charge will result in lower brightness at a given kappa number. The paper also touches upon the opportunities using advanced process control systems for bleach plants, and the process and economic improvements which can be made by properly accounting for disturbances such as carryover variability.

Place, publisher, year, edition, pages
TAPPI Press, 2017
Keywords
Bleach plant control, Dissolved lignin carryover, Filtrate kappa number, Peroxide bleaching, Pulp washing, Bleaching, Cleaning, Delignification, Dissolution, Dissolved oxygen, Intelligent control, Lignin, Oxidation, Peroxides, Advanced Process Control, Bleach plant, Dissolved lignin, Economic improvements, Kappa numbers, Lignin concentration, Oxygen delignifications, Process control
National Category
Chemical Sciences
Research subject
Chemistry
Identifiers
urn:nbn:se:kau:diva-69135 (URN)2-s2.0-85052155700 (Scopus ID)9781510852464 (ISBN)
Conference
PEERS Conference 2017: Maximizing Success Through Innovation, 5 November 2017 through 8 November 2017
Available from: 2018-09-07 Created: 2018-09-07 Last updated: 2018-09-10Bibliographically approved
Wilke, C., Andersson, N. & Germgård, U. (2017). Impact of dissolved matter in the oxygen delignification stage. TAPPI Journal, 16(5), 275-284
Open this publication in new window or tab >>Impact of dissolved matter in the oxygen delignification stage
2017 (English)In: TAPPI Journal, ISSN 0734-1415, Vol. 16, no 5, p. 275-284Article in journal (Refereed) Published
Abstract [en]

The presence of dissolved matter in the pulp suspension in an oxygen (O-2) delignification stage, consisting mainly of dissolved lignin, is normally considered to negatively affect the delignification rate due to the competing reactions between the fiber bound lignin and the lignin dissolved in the filtrate. Recirculated oxidized filtrate from the post-O-2 washing is usually considered to be less harmful to the delignification efficiency than unoxidized dissolved matter originating from the cooking stage. To develop a better understanding of the mechanisms of the dissolved matter's reactions and impact on the O-2 stage performance, laboratory oxygen delignification experiments with varying levels of unoxidized and oxidized dissolved matter were conducted. The results showed that unoxidized dissolved matter had a negative impact on the delignification in the O-2 stage, whereas oxidized dissolved matter actually had a positive effect. The delignification efficiency of the laboratory experiments thus depends on both the amount of dissolved matter and its origin. The pulp viscosity decreased with increasing dissolved matter content irrespective of its origin but at higher COD levels; however, the viscosity drop was larger for the unoxidized dissolved matter. In terms of selectivity, the oxidized filtrate had a similar impact as additional NaOH charge. Both types of filtrates consumed hydroxide and the final pH decreased with increasing dissolved matter content. The final pH was significantly lower in the unoxidized filtrate experiments at higher COD levels, indicating a high reactivity between the unoxidized dissolved matter and the oxygen in the reactor. Based on the results, further understanding is achieved about the relation between pre-O-2 washing performance and process configuration in an actual mill case, as well as the impact of dissolved matter on delignification. The importance of efficient removal of harmful unoxidized dissolved matter is verified, but the results also suggest that the oxidized dissolved matter that is recirculated from post-O-2 washing actually has a significant positive impact on the delignification and is not just a potential problem in case of carryover to the bleach plant. Subsequently, pulp washing efficiency is critical both pre- and post-O-2.

Place, publisher, year, edition, pages
TAPPI Press, 2017
National Category
Chemical Engineering
Research subject
Chemical Engineering
Identifiers
urn:nbn:se:kau:diva-65647 (URN)000403367800004 ()
Available from: 2018-01-17 Created: 2018-01-17 Last updated: 2018-07-05Bibliographically approved
Andersson, N., Wilke, C., Akhlesh, M., Smith, D. & Germgård, U. (2017). Measurement of Dissolved Lignin, and its Impact in Fiberline Unit Operations. In: : . Paper presented at The 19th International Pulp Bleaching Conference, Aug. 28-30, 2017. Porto Seguro, BA, Brazil (pp. 1-7).
Open this publication in new window or tab >>Measurement of Dissolved Lignin, and its Impact in Fiberline Unit Operations
Show others...
2017 (English)Conference paper, Oral presentation with published abstract (Refereed)
Keywords
Online measurement; Advanced process control; Dissolved lignin; Oxygen delignification; Chlorine dioxide bleaching
National Category
Chemical Engineering
Research subject
Chemical Engineering
Identifiers
urn:nbn:se:kau:diva-62607 (URN)
Conference
The 19th International Pulp Bleaching Conference, Aug. 28-30, 2017. Porto Seguro, BA, Brazil
Available from: 2017-08-10 Created: 2017-08-10 Last updated: 2018-09-07Bibliographically approved
Germgård, U. (2017). The Arrhenius Equation is Still a Useful Tool in Chemical Engineering. Nordic Pulp & Paper Research Journal, 32(1), 21-24
Open this publication in new window or tab >>The Arrhenius Equation is Still a Useful Tool in Chemical Engineering
2017 (English)In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 32, no 1, p. 21-24Article in journal (Refereed) Published
Abstract [en]

The Arrhenius equation correlates the rate of a chemical reaction with the corresponding activation energy, reaction time and reaction temperature, where the latter is measured in Kelvin. Although the equation is rather simple it can be used to summarize the kinetics of most chemical reactions in a surprisingly good manner. The activation energy is an interesting parameter that can be seen as an energy barrier which the reacting chemicals have to pass before a chemical reaction is initiated. Thus, the higher the activation energy, the lower is the rate of the chemical reaction. Moreover, the equation can also be used, for example, to forecast the influence of a higher temperature on the composition of a product consisting of components with different activation energies. In such a case, a component with higher activation energy will increase its rate of reaction more than a component with lower activation energy. The composition of the original product will thus obtain a shrinking fraction of the fast reacting component. The report gives some guidelines of how to calculate the activation energy for a given case in a pulp mill.

Place, publisher, year, edition, pages
AB SVENSK PAPPERSTIDNING, 2017
Keywords
Activation energy, Cellulose, Hemicellulose, Kinetics, Kraft pulping, Lignin, Sulfite pulping
National Category
Chemical Engineering
Research subject
Chemistry
Identifiers
urn:nbn:se:kau:diva-65407 (URN)10.3183/NPPRJ-2017-32-01-p021-024 (DOI)000398384400003 ()
Available from: 2017-12-14 Created: 2017-12-14 Last updated: 2018-08-15Bibliographically approved
Wilke, C., Andersson, N., Van Fleet, R., Mathur, A. & Germgard, U. (2016). Impact of dissolved lignin in oxygen delignification and chlorine dioxide stages. Paper presented at Conference on Pulping, Engineering, Environmental, Recycling, Sustainability (PEERS), OCT 25-28, 2015, Atlanta, GA. TAPPI Journal, 15(3), 167-174
Open this publication in new window or tab >>Impact of dissolved lignin in oxygen delignification and chlorine dioxide stages
Show others...
2016 (English)In: TAPPI Journal, ISSN 0734-1415, Vol. 15, no 3, p. 167-174Article in journal (Refereed) Published
Abstract [en]

While carryover of dissolved lignin between stages in the pulp mill fiber line is a well-known problem, it is still typically seen only as a minor disturbance factor or bias in the control of oxygen (O-2) delignification and bleaching stages. The present study, however, reveals that it plays a larger role than anticipated, and that it should be properly analyzed in order to correctly control the process stages. This is especially important for the O-2 and D-0 stages as the lignin content is still high in these positions. The results of the study show that dissolved lignin carried over between stages may have a significant impact on the bleaching chemical consumption and, indirectly, on the pulp quality. Mill investigations have shown very large variations in the dissolved lignin content in the pulp before the oxygen delignification stage and before the D-0 stage that have significantly influenced the bleaching chemical demand and, subsequently, the degree of delignification. In order to develop a better understanding of the mechanisms of the dissolved lignin's reactions, laboratory O-2 and D-0 experiments with controlled levels of dissolved lignin were conducted. It was anticipated that a better feedforward control could be achieved using an online dissolved lignin measurement, and results from mill trials are presented. Chlorine dioxide laboratory experiments using different levels of carryover (i.e., different dissolved lignin contents) were conducted. It was concluded that the filtrate kappa number provides a relevant measure of the bleach demand due to the dissolved lignin and that, subsequently, the combined fiber and filtrate kappa number provides an appropriate measure for optimum feedforward control of the stages. Mill results support these findings, which show that the chemical consumption is reduced significantly using the total kappa number. The post-D or post-DE kappa number feedback control can most probably be eliminated by using this technology.

National Category
Chemical Engineering
Research subject
Chemical Engineering
Identifiers
urn:nbn:se:kau:diva-42029 (URN)000373923900004 ()
Conference
Conference on Pulping, Engineering, Environmental, Recycling, Sustainability (PEERS), OCT 25-28, 2015, Atlanta, GA
Available from: 2016-05-13 Created: 2016-05-13 Last updated: 2018-07-02Bibliographically approved
Magnusson, H., Kvarnlöf, N., Henriksson, G. & Germgård, U. (2016). Integrating prehydrolysis kraft pulping of softwood and viscose fibre manufacturing. Appita journal, 69(3), 264-272
Open this publication in new window or tab >>Integrating prehydrolysis kraft pulping of softwood and viscose fibre manufacturing
2016 (English)In: Appita journal, ISSN 1038-6807, Vol. 69, no 3, p. 264-272Article in journal (Refereed) Published
Abstract [en]

This work investigates the potential to integrate modern viscose manufacturing with prehydrolysis kraft pulping in order to improve the economic and environmental feasibility for production of regenerate cellulose fibers from wood. The study is largely based on calculations from literature data, but key stages are also tested experimentally. It is concluded that a kraft pulp mill can supply the acid demands of the viscose plant via acetic acid formed in the prehydrolysis and sulphuric acid for coagulation, with alkali for mercerization and dissolution, and it can also take care of spent liquors from the viscose plant. The pulp used for regenerated cellulose manufacture is delivered as wet pulp from the pulp mill, no drying is needed and a considerable amount of energy is saved. However, in an integrated production the viscose mill cannot use the whole production of cellulose from the kraft mill. One method of removing zinc ions from the coagulation bath effluents, based on precipitation of zinc sulphide via a well-controlled addition of green liquor from the pulp mill, has been studied.

Place, publisher, year, edition, pages
Macleod Vic, Australia: Appita, Inc., 2016
Keywords
biorefinery, integrated production, pre-hydrolysis kraft pulping, regenerated cellulose, viscose process.
National Category
Engineering and Technology
Research subject
Chemical Engineering
Identifiers
urn:nbn:se:kau:diva-37229 (URN)000393846900020 ()
Available from: 2015-08-03 Created: 2015-08-03 Last updated: 2017-09-27Bibliographically approved
Deshpande, R., Sundvall, L., Grundberg, H. & Germgård, U. (2016). The influence of different types of bisulfite cooking liquors on pine wood components. BioResources, 11(3), 5961-5973
Open this publication in new window or tab >>The influence of different types of bisulfite cooking liquors on pine wood components
2016 (English)In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 11, no 3, p. 5961-5973Article in journal (Refereed) Published
Abstract [en]

Single stage sodium bisulfite cooking of pine was carried out to study the initial phase of the bisulfite cook and the experiments were carried out using either a lab or a mill prepared cooking acid. The chemical consumption, the pH profile and the pulp yield with respect to cellulose, lignin, glucomannan, xylan and extractives were investigated. The pulp composition with respect to carbohydrates and lignin content was summarized in a kinetic model. The initial phase of the bisulfite cook was extended to 5 h cooking time down to a final pulp yield of about 60 %. The side reactions with respect to thiosulfate and sulfate formation were investigated continuously in all experiments. The cooking temperature used in these experiments was 154 °C.

Place, publisher, year, edition, pages
Raleigh: North Carolina State University, 2016
Keywords
Activation energy, bisulfite pulping, cellulose, extractives, glucomannan, lignin, pine, thiosulfate and xylan.
National Category
Chemical Engineering
Research subject
Chemical Engineering
Identifiers
urn:nbn:se:kau:diva-37304 (URN)10.15376/biores.11.3.5961-5973 (DOI)000384922400025 ()
Note

This paper was published as manuscript in the thesis and was then called "The Initial Phase of Sodium Bisulfite Pulping of Pine", Part II.

Available from: 2015-08-10 Created: 2015-08-06 Last updated: 2017-11-02Bibliographically approved
Deshpande, R., Germgård, U., Sundvall, L. & Grundberg, H. (2016). The Initial Phase of Sodium Bisulfite Pulping of Pine, Part II. Nordic Pulp & Paper Research Journal, 31(3), 379-385
Open this publication in new window or tab >>The Initial Phase of Sodium Bisulfite Pulping of Pine, Part II
2016 (English)In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 31, no 3, p. 379-385Article in journal (Refereed) Published
Abstract [en]

Single stage sodium bisulfite cooking of pine was carried out to investigate the influence of time and temperature in the initial phase of the cook. The cooking experiments were carried out using either a lab or a mill prepared cooking acid and the initial stage of the cook was extended up to 5 h cooking time. The impact of temperature on wood components and side reactions was analyzed between 142°C and 165°C. Arrhenius equation was used to determine the influence of temperature on wood components during the initial phase of bisulfite cooking and the activation energy was calculated for delignification rate, cellulose degradation and hemicellulose dissolution with regard to glucomannan and xylan. The extent of extractives removal at different temperature and time was also analyzed.

Place, publisher, year, edition, pages
Härnösand: Mittuniversitetet, 2016
Keywords
Bisulfite pulping, cellulose, extractives, glucomannan, kinetics, lignin, pine, sulfate, thiosulfate and xylan.
National Category
Chemical Engineering
Research subject
Chemical Engineering
Identifiers
urn:nbn:se:kau:diva-37303 (URN)
Funder
Knowledge Foundation
Note

This paper was in manuscript form in Raghu Deshpande's licentiate thesis.

Available from: 2015-08-10 Created: 2015-08-06 Last updated: 2017-12-04Bibliographically approved
Deshpande, R., Sundvall, L., Grundberg, H. & Germgård, U. (2016). The Initial Phase of Sodium Bisulfite Pulping of Spruce: Part 1. Cellulose Chemistry and Technology, 50(2), 293-300
Open this publication in new window or tab >>The Initial Phase of Sodium Bisulfite Pulping of Spruce: Part 1
2016 (English)In: Cellulose Chemistry and Technology, ISSN 0576-9787, Vol. 50, no 2, p. 293-300Article in journal (Refereed) Published
Keywords
bisulphite cooking, cellulose, glucomannan, kinetics, lignin, spruce, thiosulphate and xylan
National Category
Chemical Engineering
Research subject
Chemical Engineering
Identifiers
urn:nbn:se:kau:diva-41142 (URN)000376835600015 ()
Available from: 2016-03-29 Created: 2016-03-29 Last updated: 2017-11-30Bibliographically approved
Organisations

Search in DiVA

Show all publications