| 1. |
- Björnsson, Lovisa, et al.
(author)
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Integrating bio-oil production from wood fuels to an existing heat and power plant - evaluation of energy and greenhouse gas performance in a Swedish case study
- 2021
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In: Sustainable Energy Technologies and Assessments. - : Elsevier. - 2213-1388 .- 2213-1396. ; 48
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Journal article (peer-reviewed)abstract
- Combined heat and power (CHP) production in combination with a district heating (DH) grid gives an energy efficient use of wood fuels. The heat demand in the DH grid will, however, decline in the coming decades, and operators are seeking additional heat sinks. In this case study, the integration of a pyrolysis unit into an existing CHP plant was investigated as a possible solution. The retrofitted pyrolysis unit makes use of excess heat and yields a liquid bio-oil. Pyrolysis integrated with CHP production was shown to give a net energy yield of at least 80%, and to decrease the net heat output to the DH grid. The carbon footprint of the delivered heat was very low at maximum 1.6 g CO(2)eq/MJ. Prolonging the operation of the pyrolysis unit to periods without heat delivery to the DH grid would increase the use of existing installations, but at the cost of energy yields decreasing to 63-70%. Up to 2.8 PJ(LHV)/yr crude bio-oil could be produced at the investigated CHP plant. The bio-oil was shown to have a low carbon footprint, 1.7-4.0 g CO(2)eq/MJ(LHV), which makes it attractive for the rapidly expanding transport biofuel market.
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| 2. |
- Gustavsson, Christer, 1968-
(author)
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Added value from biomass by broader utilization of fuels and CHP plants
- 2016
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Doctoral thesis (other academic/artistic)abstract
- The present work, where additional value-creating processes in existing combined heat and power (CHP) structures have been examined, is motivated by a political- and consumer-driven strive towards a bioeconomy and a stagnation for the existing business models in large parts of the CHP sector.The research is based on cases where the integration of flash pyrolysis for co-production of bio-oil, co-gasification for production of fuel gas and synthetic biofuels as well as leaching of extractable fuel components in existing CHP plants have been simulated. In particular, this work has focused on the CHP plants that utilize boilers of fluidized bed (FB) type, where the concept of coupling a separate FB reactor to the FB of the boiler forms an important basis for the analyses. In such dual fluidized bed (DFB) technology, heat is transferred from the boiler to the new reactor that is operating with other fluidization media than air, thereby enabling other thermochemical processes than combustion to take place. The result of this work shows that broader operations at existing CHP plants have the potential to enable production of significant volumes of chemicals and/or fuels with high efficiency, while maintaining heat supply to external customers.Based on the insight that the technical preconditions for a broader operation are favourable, the motivation and ability among the incumbents in the Swedish CHP sector to participate in a transition of their operation towards a biorefinery was examined. The result of this assessment showed that the incumbents believe that a broader operation can create significant values for their own operations, the society and the environment, but that they lack both a strong motivation as well as important abilities to move into the new technological fields.If the concepts of broader production are widely implemented in the Swedish FB based CHP sector, this can substantially contribute in the transition towards a bioeconomy.
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| 3. |
- Gustavsson, Christer, 1968-, et al.
(author)
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Co-production of gasification based biofuels in existing combined heat and power plants – Analysis of production capacity and integration potential
- 2016
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In: Energy. - : Elsevier BV. - 1873-6785 .- 0360-5442. ; 111, s. 830-840
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Journal article (peer-reviewed)abstract
- Solid fuel fired fluidized bed (FB) boilers are common in combined heat and power (CHP) plants in district heating- and process industry. In this study, utilization of such FB boilers for production of syngas in dual fluidized bed gasifiers and subsequent catalytic biofuel production to substitute natural gas (SNG), methanol (MeOH) and Fischer-Tropsch fuel (FT) has been examined. Based on the hypothesis that waste-heat and tail gas from the biofuel processes can be utilized in the CHP plant, process configurations aiming for operationally robustness and low investment cost rather than maximum stand-alone efficiency have been explored and implemented in actual industrial cases and over the full operating range of the boilers. The results of the study show that significant improvements of overall efficiency can be achieved by integration of the biofuel processes in the CHP plants and that a relatively high biofuel production capacity can be achieved. SNG showed the highest obtainable efficiency and production capacity of the studied biofuels, whereas the FT process showed largest increase in terms of efficiency when integrated in the CHP plant, compared to its stand-alone efficiency.
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| 4. |
- Gustavsson, Christer, 1968-, et al.
(author)
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Co-production of pyrolysis oil in district heating plants : Systems analysis of dual fluidized-bed pyrolysis with sequential vapor condensation
- 2013
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In: Energy & Fuels. - : American Chemical Society (ACS). - 0887-0624 .- 1520-5029. ; 27:9, s. 5313-5319
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Journal article (peer-reviewed)abstract
- Flash pyrolysis of biomass yields a liquid applicable as a fuel oil substitute and as a basis for production of chemicals and fuels. Biomass, being a renewable resource, is foreseen to be in increasing demand. An increased usage may lead to scarcity of biomass and emphasizes the need for high-efficiency conversion processes. In this study, the efficiency and capacity aspects of an integration of pyrolysis oil production with a district heating plant by means of dual fluidized-bed technology has been modeled. Further, fractional condensation of the pyrolysis vapors has been applied, enabling part of the condensation energy to be recovered. The concept shows potential for significant pyrolysis oil production while keeping the delivered power and heat constant. The use of excess heat from the pyrolysis production in the district heating net results in a 10% higher overall efficiency than production without heat supply to the district heating net.
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| 5. |
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| 6. |
- Gustavsson, Christer, 1968-, et al.
(author)
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Syngas as an Additional Energy Carrier in the Pulp and Paper Industry : A Mill-Wide System Analysis of a Combined Drying Concept, Utilizing On-Site Generated Gas and Steam
- 2014
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In: Energy & Fuels. - Washington, DC, USA : American Chemical Society (ACS). - 0887-0624 .- 1520-5029. ; 28:9, s. 5841-5848
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Journal article (peer-reviewed)abstract
- Large amounts of thermal energy are required for different unit operations in the pulp and paper industry. Typically, this energy is distributed by means of steam. In this study, introduction of in-situ-generated syngas as an energy carrier in parallel to the predominant steam has been investigated. The examined systems use dual fluidized-bed gasification integrated with a solid fuel boiler of a paper mill together with impingement drying in combination with cylinder drying, a concept enabling higher specific drying rates. The studied systems exhibit reduced overall energy use when compared to the present situation with conventional steam-heated cylinder drying. Cold tar cleaning by condensation/absorption and firing of the syngas in a gas turbine followed by utilization of the exhaust gases for drying are interesting options because this results in reduced biomass consumption with maintained power production.
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| 7. |
- Kihlman, Jonas, 1982-
(author)
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On the resource efficiency of kraft lignin extraction
- 2021
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Licentiate thesis (other academic/artistic)abstract
- Lignin is regarded as a promising raw material for the production of biobased products, such as chemicals, materials and fuels, and will most probably be a key component in future lignocellulosic biorefineries.This thesis examines the lignin extraction process in a kraft pulp mill, the technologies that are available for this purpose, and the impact made on the mill. Several different kraft lignin extraction processes and technologies are currently available and are basically linear: chemicals are brought from outside the mill and introduced into the process and the mill balance. Depending on their origin, the addition of these chemicals will affect the mill to a lesser or greater degree, both economically and environmentally. A conceivable way of reducing the impact made on the mill´s balance would be the in-house production of the chemicals used, sulphuric acid and CO2, which takes a more sustainable circular approach.The results obtained show that utilisation of existing process streams in the mill as a source of chemicals could be a way of not only reducing these impacts but also making lignin extraction more sustainable. Internal production of sulphuric acid is possible and could generate a substantial amount for use as replacement of the fresh sulphuric acid needed for the lignin extraction process; CO2 is available in large quantities in the mill and could be captured and used for lignin extraction.
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| 8. |
- Kihlman, Jonas, 1982-, et al.
(author)
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The feasibility of utilizing existing process streams in kraft pulp mills as a source of chemicals for lignin extraction
- 2021
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In: BioResources. - : North Carolina State University. - 1930-2126. ; 16:1, s. 1009-1028
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Journal article (peer-reviewed)abstract
- Lignin is a sustainable raw material with a high potential for use in the production of renewable products. While the market for lignin is slowly growing, lignin recovery via acid precipitation during the kraft pulping process requires the addition of chemicals that will impact the chemical balance of the pulp mill. This negatively affects both the environmental and business operations. Utilizing existing process streams as a source of chemicals will allow the mill to close the chemical loop and reduce emissions, which will have positive environmental impacts. This study investigated the internal production of sulphuric acid (H2SO4) and carbon dioxide (CO2) for use in lignin separation (also called extraction) at a Swedish kraft pulp mill. The process simulation tool CHEMCAD was used to model and analyze the wet gas H2SO4 (WSA) process to produce H2SO4. The chemical absorption process using monoethanolamine (MEA) to capturing CO2 was also analyzed. The utilization of the sulphur-containing gases to produce H2SO4 can generate an amount that corresponds to a significant lignin extraction rate. The CO2 available in the flue gases from a mill well exceeds the amount required for lignin extraction.
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