Ny BRC publikation!

Methane potentials and organic matter characterization of wood fibres from pulp and paper mills: The influence of raw material, pulping process and bleaching technique

Eva-Maria Ekstrand, Mattias Hedenström, Bo Håkan Svensson, Sepehr Shakeri Yekta, Annika Björn

Highlights

• Kraft and sulphite fibres had high and stable CH4 potentials (390–400 Nml CH4 g VS-1).
• Shifts in raw material gave large variations in CH4 potential for CTMP fibres.
• Removal of lignin was the most important factor for high CH4 potential.
• Bleaching of CTMP softwood improved CH4 potential, likely by deacetylation.
• Unbleached TMP fibres were inhibitory to AD, while bleaching alleviated this effect.

Abstract: During the process of pulp- and papermaking, large volumes of fibre-rich primary sludge are generated. Anaerobic digestion of primary sludge offers a substantial potential for methane production as an alternative approach to the inefficient energy recoveries by commonly used incineration techniques. However, a systematic study of the importance of upstream process techniques for the methane potential of pulp fibres is lacking. Therefore, biochemical methane potentials were determined at mesophilic conditions for 20 types of fibres processed by a variety of pulping and bleaching techniques and from different raw materials. This included fibres from kraft, sulphite, semi-chemical, chemical thermo-mechanical (CTMP) and thermo-mechanical pulping plants and milled raw wood. The pulping technique was clearly important for the methane potential, with the highest potential achieved for kraft and sulphite fibres (390–400 Nml CH4 g VS− 1 ). For raw wood and CTMP, hardwood fibres gave substantially more methane than the corresponding softwood fibres (240 compared to 50 Nml CH4 g VS− 1 and 300 compared to 160 Nml CH4 g VS− 1 , respectively). Nuclear magnetic resonance characterization of the organic content demonstrated that the relative lignin content of the fibres was an important factor for methane production, and that an observed positive effect of bleaching on the methane potential of softwood CTMP fibres was likely related to a higher degree of deacetylation and improved accessibility of the hemicellulose. In conclusion, fibres from kraft and sulphite pulping are promising substrates for methane production irrespective of raw material or bleaching, as well as fibres from CTMP pulping of hardwood.

Här kan ni läsa publikationen (på engelska):

Ekstrand et. al 2020. Biomass and Bioenergy 143: 105824

 

Ny BRC publikation!

Post-treatment of dewatered digested sewage sludge by thermophilic high-solid digestion for pasteurization with positive energy output

Erik Nordell, Jan Moestedt, Julia Österman, Sepehr Shakeri Yekta, Annika Björn, Li Sun, Anna Schnürer

Highlights

• Thermophilic dry digestion of DDS increases methane yield by 6%.
• Thermophilic dry digestion of DDS at 52 °C efficiently converts organic N.
• Thermophilic dry digestion of DDS is stable at high free ammonia levels (2 g/L)
• Increasing ammonia level enriches members of the methanogenic family WSA2.
• Sanitization of DDS by thermophilic dry digestion has a positive energy balance.

Abstract: This study investigated the possibility to use thermophilic anaerobic high solid digestion of dewatered digested sewage sludge (DDS) at a wastewater treatment plant (WWTP) as a measure to increase total methane yield, achieve pasteurization and reduce risk for methane emissions during storage of the digestate. A pilot-scale plug-flow reactor was used to mimic thermophilic post-treatment of DDS from a WWTP in Linköping, Sweden. Process operation was evaluated with respect to biogas process performance, using both chemical and microbiological parameters. Initially, the process showed disturbance, with low methane yields and high volatile fatty acid (VFA) accumulation. However, after initiation of digestate recirculation performance improved and the specific methane production reached 46 mL CH4/g VS. Plug flow conditions were assessed with lithium chloride and the hydraulic retention time (HRT) was determined to be 19–29 days, sufficient to reach successful pasteurization. Degradation rate of raw protein was high and resulted in ammonia-nitrogen levels of up to 2.0 g/L and a 30% lower protein content in the digestate as compared to DDS. Microbial analysis suggested a shift in the methane producing pathway, with dominance of syntrophic acetate oxidation and the candidate methanogen family WSA2 by the end of the experiment. Energy balance calculations based on annual DDS production of 10 000 ton/year showed that introduction of high-solid digestion as a post-treatment and pasteurization method would result in a positive energy output of 340 MWh/year. Post-digestion of DDS also decreased residual methane potential (RMP) by>96% compared with fresh DDS.

Här kan ni läsa publikationen (på engelska):

   Nordell et al. 2021. Waste Management 119 (1): 11-21

 

Ny BRC publikation!

Cleaner heavy transports – Environmental and economic analysis of liquefied natural gas and biomethane

Marcus Gustafsson och Niclas Svensson

Abstract: Looking to reduce climate change impact and particle emissions, the heavy-duty transport sector is moving towards a growth within technology and infrastructure for use of liquefied natural gas (LNG). This opens an opportunity for the biogas market to grow as well, especially in the form of liquefied biomethane (LBM). However, there is a need to investigate the economic conditions and the possible environmental benefits of using LBM rather than LNG or diesel in heavy transports. This study presents a comparison of well-to-wheel scenarios for production, distribution and use of LBM, LNG and diesel, assessing both environmental and economic aspects in a life cycle perspective. The results show that while LNG can increase the climate change impact compared to diesel by up to 10%, LBM can greatly reduce the environmental impact compared to both LNG and diesel. With a German electricity mix, the climate change impact can be reduced by 45 – 70% compared to diesel with LBM from manure, and by 50 – 75% with LBM from food waste. If digestate is used to replace mineral fertilizer, the impact of LBM can even be less than 0. However, the results vary a lot depending on the type of feedstock, the electricity system and whether the calculations are done according to RED or ISO guidelines. Economically, it can be hard for LBM to compete with LNG, due to relatively high production costs, and some form of economic incentives are likely required.

Här kan ni läsa publikationen (på engelska):

    Gustafsson & Svensson 2020. Journal of Cleaner Production 123535

Ny BRC publikation!

Dimensions and characteristics of biogas policies – Modelling the European policy landscape

Marcus Gustafsson och Stefan Anderberg

Abstract: Biogas solutions typically span across several sectors, such as waste handling, energy and transport. While this can be an advantage in comparison to other alternatives, it also creates an intricate policy structure that is challenging to overview, making it difficult to evaluate consequences of different policy changes that might not be directly related to biogas. This article presents an attempt to describe the institutional conditions for biogas solutions in the EU by defining the dimensions and characteristics of policies and policy instruments influencing biogas. A five-dimensional model of biogas policies is proposed: type of policy; administrative area; administrative level; targeted part of the value chain; and continuity and change over time. This reflects the complexity of the conditions for biogas solutions and constitutes a platform for describing, discussing and developing biogas policies. From the proposed model, it becomes clear that biogas policy is a very dispersed and incoherent policy area. Thus, there is an apparent risk that the responsibility for biogas policy is diffuse and has no obvious owner among the involved actors, making the framework of biogas policies patchy and ineffective. This model can contribute to an improved overview of biogas policies, and can be used as a tool for comparing the policy landscapes in different countries.

Här kan ni läsa publikationen (på engelska):

  Gustafsson & Anderberg 2021. Renewable and Sustainable Energy Reviews 135: 110200

Ny BRC publikation!

Developing biogas systems in Norrköping, Sweden: An industrial symbiosis intervention

Axel Lindfors, Marcus Gustafsson, Stefan Anderberg, Mats Eklund, Murat Mirata

Abstract: Biogas systems are often multi-functional and involve several actors in different sectors, requiring these actors to collaborate closely in order to implement such systems. In this paper, a study is presented where the theory of institutional capacity building is used to guide interventions with public and private actors to facilitate the development of local biogas systems in Norrköping, Sweden. The interventions were performed in the form of a workshop series, where local actors with potential to influence biogas developments actively took part. The workshop series generated knowledge on Norrköping’s significant potential for both producing and using biogas, which was traced, in part, to its high concentration of bio-based industries and its good position as a hub for transports. The interventions also created a shared understanding that cooperation and coordination to distribute resources and knowledge about biogas, both geographically and across sectors, was critical for realizing this potential. The municipal organization was identified as an important actor for coordinating these efforts. Observations during the workshops and survey responses indicate that the interventions contributed to building institutional capacity and initiation of efforts to develop local biogas solutions. Ideas put forth in this study enable interventions to target the intangible internal capacities of emerging industrial symbiosis networks. In addition, institutional capacity building serves as a useful analytical framework capable of capturing progress within emerging networks in the short-term even when material, water or energy synergies are yet to be realized.

Här kan ni läsa publikationen (på engelska):

  Lindfors et al. 2020. Journal of Cleaner Production 277: 122822

Ny BRC publikation!

Socio-technical scenarios and local practice – Assessing the future use of fossil-free alternatives in a regional energy and transport system

Thomas Magnusson, Stefan Anderberg, Sofia Dahlgren, Niclas Svensson

Highlights

•Presents socio-technical scenarios for electric buses, biogas and biodiesel
•Collaborative research approach involving local decision-makers
•Focus on near-term implementation and commercial operation
•Methodological lessons on system delineation, timing, conflict resolution and agency

Abstract: This article presents results from a project involving local practitioners in the construction of scenarios for a regional energy and transport system. The purpose is to demonstrate how sustainability transitions research can interact with local practice by means of socio-technical scenarios. Combining quantitative data with qualitative storylines, the article presents four scenarios, which describe different ways of using biogas, biodiesel and electricity in four different applications: city buses, inter-city buses, heavy-duty trucks and industrial processes. The article compares the four scenarios in terms of realization possibilities, energy efficiency and greenhouse gas reduction. Focusing on near-term realization on a commercial basis, the research findings suggest that collaborative scenario construction can be a useful strategy to manage conflicting agendas and engage key stakeholders in dialogues on transition pathways. The article concludes by presenting policy lessons for practice-oriented transition management. The lessons point to the importance of flexibility in system delineations, the critical timing of near-term scenarios, and the use of scenarios to outline local practitioners’ agency.

Här kan ni läsa publikationen (på engelska):

Magnusson et al. 2020. Transportation Research Interdisciplinary Perspectives 5: 100128

Ökat Värde ur Digestat

Forskningen vid Biogas Research Center (BRC) i Linköping har gått in i en tredje etapp och tar nu upp området rötrest (digestat) och vilka möjligheter det finns att höja värdet på rötresten som kommer ut från biogasanläggningar. Flera olika ansatser används.

Läs nyhetsbrev Ökat Värde ur Digestat:

New IEA report: Global Outlook on Biogas and Biomethane – Prospects for Organic Growth

   

The International Energy Agency published a new report about the global outlook on biogas and biomethane.

”This report provides estimates of the sustainable potential for biogas and biomethane supply, based on a detailed assessment of feedstock availability and production costs across all regions of the world. These form the basis on an outlook for biogas and biomethane supply and demand up to 2040, based on the scenarios presented in the annual World Energy Outlook.”

Link to the publication: https://webstore.iea.org/outlook-for-biogas-and-biomethane

Read the press release Organic waste has huge untapped potential to provide clean energy around the world.

 

 

Produktion och distribution av komprimerad och flytande biogas

Biogas spås utgöra ett betydande bidrag till ett framtida fossilfritt transportsystem. Men vilka metoder för produktion och distribution av biogas till fordon är mest effektiva, och när blir det mer effektivt att göra flytande biogas? BRC-forskaren Marcus Gustafsson och medförfattare undersöker energibalansen, miljöpåverkan och ekonomiska aspekter av olika tekniker för uppgradering, förvätskning och distribution av biogas för användning som fordonsbränsle.

Läs artikeln här (populärvetenskaplig version på svenska):

Länken till publikationen (på engelska): Gustafsson et al. 2020. Scenarios for upgrading and distribution of compressed and liquefied biogas – Energy, environmental, and economic analysis. Journal of Cleaner Production 256

Biogasen löser flera problem samtidigt!

Foto: Malin Hoelstad

Sluta stirra er blinda på ett enskilt mål, man måste se brett för att förstå biogasens alla fördelar och samhällsnyttor. Så säger Mats Eklund i en intervju som tidningen Energigas Sverige gjort. Förutom biogasens nyttor talar Mats om kommuner och regioner som legat i framkant, lastbilsjättar som driver på positiv utveckling för flytande biogas, och hur Sverige ska ta vara på sin roll som världsledande på biogas som fordonsbränsle.

Det blir även  snack om när han var biogasmissionär på Kuba och – såklart – en hel del om BRCs forskning.

Missa ej! Läs hela artikeln här.