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- Berglund Odhner, Peter, et al.
(författare)
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Biogas from lignocellulosic biomass
- 2012
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Grontmij AB has cooperated with the University of Borås to evaluate the technological and economical possibilities for biogas production from substrates containing lignocellulose, such as forest residues, straw and paper. The state of knowledge regarding biogas production from cellulosic biomass has been summarized. The research in the field has been described, especially focusing on pretreatment methods and their results on increased gas yields. An investigation concerning commercially available pretreatment methods and the cost of these technologies has been performed. An economic evaluation of biogas production from lignocellulosic materials has provided answers to questions regarding the profitability of these processes. Pretreatment with steam explosion was economically evaluated for three feedstocks – wood, straw and paper – and a combination of steam explosion and addition of NaOH for paper. The presented costs pertain to costs for the pretreatment step as it, in this study, was assumed that the pretreatment would be added to an existing plant and the lignocellulosic substrates would be part of a co-digestion process. The results of the investigation indicate that it is difficult to provide a positive net result when comparing the cost of pretreatment versus the gas yield (value) for two of the feedstocks – forest residues and straw. This is mainly due to the high cost of the raw material. For forest residues the steam pretreatment cost exceeded the gas yield by over 50 %, mainly due to the high cost of the raw material. For straw, the production cost was similar to the value of the gas. Paper showed the best economic result. The gas yield (value) for paper exceeded the pretreatment cost by 15 %, which makes it interesting to study paper further.
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| 2. |
- Högstedt, Åsa, et al.
(författare)
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Characteristics and motivational factors for joining a lay responder system dispatch to out-of-hospital cardiac arrests
- 2022
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Ingår i: Scandinavian Journal of Trauma, Resuscitation and Emergency Medicine. - : Springer Science and Business Media LLC. - 1757-7241. ; 30:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: There has been in increase in the use of systems for organizing lay responders for suspected out-of-hospital cardiac arrests (OHCAs) dispatch using smartphone-based technology. The purpose is to increase survival rates; however, such systems are dependent on people's commitment to becoming a lay responder. Knowledge about the characteristics of such volunteers and their motivational factors is lacking. Therefore, we explored characteristics and quantified the underlying motivational factors for joining a smartphone-based cardiopulmonary resuscitation (CPR) lay responder system. Methods: In this descriptive cross-sectional study, 800 consecutively recruited lay responders in a smartphone-based mobile positioning first-responder system (SMS-lifesavers) were surveyed. Data on characteristics and motivational factors were collected, the latter through a modified version of the validated survey "Volunteer Motivation Inventory" (VMI). The statements in the VMI, ranked on a Likert scale (1-5), corresponded to(a) intrinsic (an inner belief of doing good for others) or (b) extrinsic (earning some kind of reward from the act) motivational factors. Results: A total of 461 participants were included in the final analysis. Among respondents, 59% were women, 48% between 25 and 39 years of age, 37% worked within health care, and 66% had undergone post-secondary school. The most common way (44%) to learn about the lay responder system was from a CPR instructor. A majority (77%) had undergone CPR training at their workplace. In terms of motivation, where higher scores reflect greater importance to the participant, intrinsic factors scored highest, represented by the category values (mean 3.97) followed by extrinsic categories reciprocity (mean 3.88) and self-esteem (mean 3.22). Conclusion: This study indicates that motivation to join a first responder system mainly depends on intrinsic factors, i.e. an inner belief of doing good, but there are also extrinsic factors, such as earning some kind of reward from the act, to consider. Focusing information campaigns on intrinsic factors may be the most important factor for successful recruitment. When implementing a smartphone-based lay responder system, CPR instructors, as a main information source to potential lay responders, as well as the workplace, are crucial for successful recruitment.
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| 3. |
- Sárvári Horváth, Ilona, et al.
(författare)
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Biogas från lignocellulosa Tekno : ekonomisk utvärdering av förbehandling med NMMO
- 2013
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Biogas has been identified as one of the most cost - effective renewable fuels. In order to increase biogas production, yields from traditionally substrates either need to be improved or other alternative substrates must be made available for anaerobic digestion. Cellulose and lignocellulose rich wastes are available in large amounts and have great potential to be utilized for biogas production. This project focused on the opti mization of the pretreatment conditions when using the organic solvent N - methylmorpholine - N - oxide (NMMO) to enhance the methane yield from forest residues and straw. It also focused on a techno - economic evaluation of this pre - treatment technology. NMMO has previously been shown to be effective in dissolving cellulose and, as a consequence, in increasing the methane yield during the subsequent digestion. The goal of this project was to develop a technology that increases energy production from domestic subst rates in a cost - effective and environmentally friendly way. The treatment works well at lower temperatures (90°C), which means that water from the district heating system can advantageously be used in the treatment. The results showed that treatment with NMMO at 90°C doubles the methane yield from forest residues and increases the methane yield from straw by 50 %. For the techno - economic evaluation, the base case was assumed to be a facility with a capacity of 100 000 tones forest residues/year. After a w ashing and filtration step, the treated material will be utilized in a co - digestion process where 33% of the incoming material consists of forest residues and the rest is source - sorted household waste. The scale - up, process design, simulation and calculati ons were made using the software tool Intelligen SuperPro Design ® . The total investment costs were calculated to be about 145 million €, when forest residues or straw are to be used as raw material. Costs for operation (i.e. raw materials, energy, waste ma nagement, maintenance and personnel costs) were set against the incomes from the products (i.e. methane, carbon dioxide and the lignin - rich digested residue) to see if the process was profitable. The internal return rate (IRR), a parameter that indicates w hether a process is profitable or not, indicated that evaluated processes with capacities over 50 000 tons forest residues/year are profitable. However, co - digestion of forest residues with sewage sludge instead of household waste was not profitable. Both the laboratory results and the energy and economic calculations showed that the washing and filtration step is critical for the proposed process. The energy balance calculation resulted in an EROI value of 0.5, which means that the produced methane from fo rest residues counted up only the half of the energy needed for the treatment as well as NMMO separation and recycling. It is important to separate the NMMO well after the treatment, since remaining NMMO at concentrations higher than 0.002% were found to i nhibit the subsequent digestion step. Also it was showed out to be important that the washing step operates with small amounts of water to save energy within the NMMO recovery. A rotary vacuum filtration is therefore recommended for the washing and filtrat ion step, and a mechanical vapor design is recommended for the evaporation, saving up to 70 - 90% energy compared to a conventional design. Treatment of straw with recycled instead of fresh NMMO has also been tested and equal amounts of methane were obtain ed. After a well - functioning washing and filtration step, NMMO could not be detected in the digestate residue.
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