| 1. |
- Andersson, Eva Ingeborg Elisabeth, 1956, et al.
(författare)
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Pulp-mill integrated biorefineries: a framework for assessing net CO2 emission consequences
- 2004
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Ingår i: Proceedings, AIChE 2004 Fall Annual Meeting. Nov 7-12, 2004, Austin, Texas, USA. ; , s. p 203-208, s. 203-208
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- There is currently much interest in producing biofuel-based transportation fuels. However, since biofuel is a limited renewable resource, it is important to assess whether such fuels are both produced and used as efficiently as possible. Efficient production can be achieved in the future by integrated biorefinery operations at pulp mill sites, co-producing pulp and biofuel-based energy products. This paper compares production of transportation fuel with other biorefinery options for future pulp mills. The comparison is based on net CO2 emissions, i.e. accounting for off-site consequences associated with changes in the net flows of electricity, biofuel and biofuel-based transportation fuel entering or leaving the mill. The most important conclusion is that system variables (e.g. assumptions regarding the reference fuel and engine efficiency for future transportation systems) are of decisive importance for the net CO2 emissions associated with pulp mill biorefinery operations. This paper illustrates such aspects and underlines the importance of a system perspective in process engineering research.
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| 2. |
- Rupar, Katarina, 1974-, et al.
(författare)
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The Release of Organic Compounds during Biomass Drying depends upon the feedstock and/or altering Drying Heating Medium
- 2003
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Ingår i: Biomass and Bioenergy. - : Elsevier. - 0961-9534 .- 1873-2909. ; 25:6, s. 615-622
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Tidskriftsartikel (refereegranskat)abstract
- The release of organic compounds during the drying of biomass is a potential environmental problem, it may contributeto air pollution or eutrophication. In many countries there are legal restrictions on the amounts of terpenes that may bereleased into the atmosphere. When considering bioenergy in future energy systems, it is important that information on theenvironmental e-ects is available. The emissions of organic compounds from di-erent green and dried biofuels that have beendried in hot air and steam medium, were analyzed by using di-erent techniques. Gas chromatography and gas chromatographymass spectrometry have been used to identify the organic matter. The terpene content was signi2cantly a-ected by thefollowing factors: changing of the drying medium and the way the same biomass was handled from di-erent localities inSweden. Comparison between spectra from dried and green fuels reveal that the main compounds emitted during dryingare monoterpene and sesquiterpene hydrocarbons, while the emissions of diterpene hydrocarbons seem to be negligible. Therelative proportionality between emitted monoterpene, diterpene and sesquiterpene change when the drying medium shiftsfrom steam to hot air. The obtained result of this work implies a parameter optimization study of the dryer with regard toenvironmental impact. With assistance of this result it might be foreseen that choice of special drying medium, diversity ofbiomass and low temperature reduce the emissions. A thermo-gravimetric analyzer was used for investigating the biomassdrying rate.
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| 3. |
- Owrang, Farshid, 1972, et al.
(författare)
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Chemical analysis of combustion products from an engine power plant fuelled with natural gas
- 2004
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Ingår i: SAE Technical Papers. - 400 Commonwealth Drive, Warrendale, PA, United States : SAE International. - 0148-7191 .- 2688-3627.
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Konferensbidrag (refereegranskat)abstract
- Combustion products, exhaust emissions and engine exhaust deposits formed on thermocouples, positioned after the heat exchanger of an engine power plant, were analyzed chemically. The engine was a lean burn 18W28SG 50 Hz (Wärtsilä NSD, Trollhättan Sweden) fuelled with natural gas equipped with a catalyst (Süd-Chemie NMHC catalyst). The exhaust emissions were sampled using the off-line bottle-in-bag (BiB) method and were analyzed by gas chromatography/flame ionization (GC/FID). Heavier organic compounds and aldehydes were separately collected using adsorption cartridges. The combustion products measured in the emissions were mainly ethene, propene and formaldehyde indicating normal combustion of the fuel in the engine. Organics contained in the engine exhaust deposits were extracted using three different extraction methods: thermal desorption (TD), liquid extraction (LE) and super critical fluid extraction (SFE). The extracts were analyzed by GC/MS. The chemical composition of the deposits before and after TD and LE was characterized using solid-state 13C NMR. The amount of oxygen in the deposits was measured using cyclic fast neutron activation analysis (cFNAA). A substantial part of the deposits (77 weight %) consisted of extractable organics. The remaining part of the deposits consisted of a carbon structure rich in aromatics and aliphatics. The amount of oxygen in the deposits was about 17 weight %. As expected, the results demonstrated that the deposits originated from engine oil. This was shown clearly using GC/MS analysis of components desorbed or extracted from the deposits combined with NMR of deposits.
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| 4. |
- Wahlund, Bertil, et al.
(författare)
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Increasing biomass utilisation in energy systems : A comparative study of CO2 reduction and cost for different bioenergy processing options
- 2004
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Ingår i: Biomass and Bioenergy. - : Elsevier BV. - 0961-9534 .- 1873-2909. ; 26:6, s. 531-544
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Tidskriftsartikel (refereegranskat)abstract
- Emissions of greenhouse gases, such as CO2, need to be greatly reduced to avoid the risk of a harmful climate change. One powerful way to mitigate emissions is to switch fuels from fossil fuels to renewable energy, such as biomass. In this paper, we systematically investigate several bioenergy processing options, quantify the reduction rate and calculate the specific cost of reduction. This paper addresses the issue of which option Sweden should concentrate on to achieve the largest CO2 reduction at the lowest cost. The results show that the largest and most long-term sustainable CO2 reduction would be achieved by refining the woody biomass to fuel pellets for coal substitution, which have been done in Sweden. Refining to motor fuels, such as methanol, DME and ethanol, gives only half of the reduction and furthermore at a higher specific cost. Biomass refining into pellets enables transportation over long distances and seasonal storage, which is crucial for further utilisation of the woody biomass potential.
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