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- Baker, Darren A., et al.
(författare)
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Opportunities in lignin based carbon fibre
- 2015
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Ingår i: NWBC 2015. - Espoo : VTT. - 9789513883539 ; , s. 244-251
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Konferensbidrag (refereegranskat)abstract
- Innventia AB's LignoBoost process enables the extraction of high purity lignin efficiently from the black liquor in kraft mills. A stream of black liquor is taken from the evaporation plant and the lignin is precipitated by acidification and filtered. The filter cake is redispersed and acidified and the resulting slurry is filtered and washed. High purity lignin can be produced at several scales, namely 10g, 1kg, 10kg and over 1,000kg. Innventia has invested significantly to demonstrate the potential of lignin as a viable feedstock for carbon fibre manufacture. Initially, the fibre melt spinning performance of the lignin is assessed using single filament melt extrusion and then melt spinning is performed at the multifilament scale, where fine fibres can be produced for conversion to carbon fibre. Oxidative thermostabilisation of the lignin fibres is carried out so that carbonisation can proceed. The effects of thermal treatment programmes and tensioning have been studied by using either thermomechanical analysis or by using test equipment specially designed to monitor carbonisation profiles with either stress or strain control. In addition, continuous processes for the conversion of lignin fibre to carbon fibre are being developed.
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- Berghel, Jonas, 1966-, et al.
(författare)
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The effects of kraft lignin additives on wood fuel pellet quality, energy use and shelf life
- 2013
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Ingår i: Fuel processing technology. - : Elsevier BV. - 0378-3820 .- 1873-7188. ; 112:0, s. 64-69
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Tidskriftsartikel (refereegranskat)abstract
- In 2011, the total consumption of pellets in Sweden amounted to 1.9 million tons, which represents an energy value of 9 TWh. The pellets are used in large-scale as well as in small-scale applications, and increased demands on pellet quality are likely to force pellet producers to improve on the pellet properties. One way of increasing pellet quality is by using additives. The purpose of this article, therefore, is to examine kraft lignin as an additive. Pelletswere produced in a small industrial pellet press located at KarlstadUniversity, Karlstad, Sweden, and 1–4% of kraft lignin was added to the pellets. The results indicate that the addition of an increased amount of kraft lignin to the pellets increases their mechanical durability and their lengths. The results also indicate that dry kraft lignin yields pellets with higher durability as compared to wet kraft lignin. The energy demand was unaffected by the increased use of kraft lignin. The general results presented in this paper are useful for producers of lignin, pellet producers and end-users of pellets, who are interested in developing their products and/or improving the production processes.
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- Berglin, Niklas, et al.
(författare)
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Experiences from feeding and co-firing of lignin powder in a lime kiln
- 2010
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Ingår i: International Chemical Recovery Conference. ; , s. 175-187
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Konferensbidrag (refereegranskat)abstract
- A significant part of the fossil fuel oil consumption at a pulp mill today is related to combustion in the lime kiln. Therefore, replacing fuel oil with lignin in this application has been one of the most important issues in the FRAM2 (Future Resource-Adapted Mill) research program coordinated by Innventia (formerly STFl-Packforsk) and funded by Sodra and other partners. A full-scale trial to fire lignin powder in a lime kiln was carried out at the Sodra Cell Monsteras mill, as part of the research program. In total 37 tonnes of lignin was co-fired with fuel oil. For part of the trial the kiln was operated on 100 % lignin. The experiences from the trial imply that it is possible to achieve stable and continuous operation of a lime kiln when lignin is used as the main fuel. The temperature levels in the kiln are of the same order of magnitude as when firing fuel oil or wood powder. Sulfur capture by the lime is very efficient, but there is a threshold above which S02 emissions increase rapidly. In the trial this step change occurred when going from 90 % to 100 % lignin firing. Based on the trial results, it is possible to produce lime with consistent quality when firing lignin, and the temperature reached in the burner zone is sufficient for proper sintering of the lime nodules. White liquor can be produced from the lime with the same causticizing efficiency and at the same rate as during normal operation. The mill operators also commented that it was easier to control the performance of the kiln when co-firing lignin and oil compared to the normal operation with co-firing of bark and oil.
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| 6. |
- Berglin, Niklas, et al.
(författare)
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Pilot-scale combustion studies with kraft lignin as a solid biofuel
- 2008
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Ingår i: Engineering, Pulping and Environmental Conference 2008. - : TAPPI Press. - 9781605605081 ; , s. 2571-2580
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Konferensbidrag (refereegranskat)abstract
- Processing of kraft lignin precipitated from black liquor to produce a solid biofuel with high energy density and low ash content has been developed in research programs by STFI-Packforsk and partners. In preparation for full-scale combustion trials, tests were carried out on pilot scale in a 150 kW powder burner and in a 12 MWfluidized bed (CFB) boiler. Lignin powder could be fired in a powder burner with good combustion performance after some trimming of the airflows to reduce swirl. Lignin dried to 10 % moisture content was easy to feed smoothly and had less bridging tendencies in the feeding system than wood/bark powder. In the CFB boiler lignin was easily handled and co-fired together with bark. Although the filter cake was broken into smaller pieces and fines the combustion was not disturbed. When co-firing lignin with bark, the sulfur emission increased compared to bark firing only, but most of the sulfur was captured by calcium in the bark ash. Conventional sulfur capture with addition of limestone to the bed was also demonstrated. The sulfur content in the lignin had a significantly positive effect on reducing the alkali chloride content in the deposits, thus reducing the high temperature corrosion risk.
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| 7. |
- Berglin, Niklas, et al.
(författare)
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Pilot-scale combustion studies with kraft lignin in a powder burner and a CFB boiler
- 2010
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Ingår i: TAPPI Journal. - 0734-1415. ; 9:6, s. 24-30
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Tidskriftsartikel (refereegranskat)abstract
- Processes have been developed to produce a solid biofuel with high energy density and low ash content from kraft lignin precipitated from black liquor. Pilot-scale tests of the lignin biofuel were carried out with a 150 kW powder burner and a 12 MW circulating fluidized bed (CFB) boiler. Lignin powder could be fired in a powder burner with good combustion performance after some trimming of the air flows to reduce swirl. Lignin dried to 10% moisture content was easy to feed smoothly and had less bridging tendencies in the feeding system than did wood/ bark powder. In the CFB boiler, lignin was easily handled and cofired together with bark. Although the filter cake was broken into smaller pieces and fines, the combustion was not disturbed. When cof ¡ring lignin with bark, the sulfur emission increased compared with bark firing only, but most of the sulfur was captured by calcium in the bark ash. Conventional sulfur capture also occurred with addition of limestone to the bed. The sulfur content in the lignin had a significantly positive effect on reducing the alkali chloride content in the deposits, thus reducing the high temperature corrosion risk. Application: This research is of interest for pulp and paper and energy and utilities companies that want to understand how kraft lignin can be used to replace fuel oil or coal in many combustion applications.
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- da Silva, Paulo S P, et al.
(författare)
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Release of carbon and nitrogen during pylolysis of reduced lignin black liquors : experimental results
- 2017
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Ingår i: International chemical recovery conference, May 24-26, 2017, Halifax, Canada.
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Konferensbidrag (refereegranskat)abstract
- Removing lignin from black liquor is of increasing industrial interest. It has the potential to create a new product stream for pulp mills as well as being a method for reducing the load of over-loaded recovery boilers. Currently, there is very little information on the combustion properties of reduced lignin black liquors. Of particular importance is the split of carbon and nitrogen. The carbon split is especially important because it plays an important role in how much carbon reaches the char bed. This in turn affects the lower furnace temperature, which plays an important role in reduction efficiency; sulfur and alkali release; and NO and cyanate formation. The nitrogen split is of interest because a part of the black liquor nitrogen precipitates with the lignin, potentially changing the behavior of black liquor N. The purpose of this work is to investigate the effect of lignin removal on carbon and nitrogen distribution between volatiles and char during pyrolysis. In this work, black liquors (one SW and one eucalyptus) with different levels of lignin removal were pyrolysed in a single particle furnace for 2 seconds at temperatures from 900°C to 1100°. Additional softwood and hardwood liquors were also pyrolyzed in order to study liquor to liquor variability. The carbon and nitrogen splits were obtained by analyzing the chars from the pyrolysis experiments using a CHNS elemental analyzer. Results show a similar carbon split for liquors with up to 25% lignin removal. The nitrogen split was also found to be fairly consistent with approximately 45% of the nitrogen staying with the char. This information has partly been used in another study in the CFD modeling of the combustion of black liquor with different levels of lignin removal.
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