| 1. |
- Göransson, Kristina, et al.
(författare)
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CATALYTIC REDUCTION OF TAR/CH4 BY AN INTERNAL REFORMER IN A DFB GASIFIER
- 2014
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Ingår i: European Biomass Conference & Exhibition Proceedings. - 9788889407523 ; , s. 620-625
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- An internal reformer is developed for in-situ catalytic reforming of tar and methane (CH4) in allothermal gasifiers. Reduction of tars and CH4 in the syngas is a challenge for commercialization of biomass fluidised-bed gasification technology towards advanced automotive fuel production. This paper presents an initial study on the internal reformer operated with and without Ni-catalytic pellets in the Mid Sweden University (MIUN) DFB (Dual Fluidised Bed) gasifier, by evaluation of the syngas composition and tar/CH4 content. The novelty with the application of Ni-catalyst in this paper is the selected location where intensive gas to catalytic-material and bed-material contacts improve the reforming reactions. It can be concluded that the reformer with Ni-catalytic pellets clearly gives a higher H2 content together with lower CH4 and tar contents in the syngas than the reformer without Ni-catalytic pellets. The gravimetric tar content decreases down to 5 g/m3 and the CH4 content down below 6% in the syngas. The tar content will be decreased further to lower levels, with increased gas contact to the specific surface area of the catalyst and increased catalyst surface-to-volume ratio. The new design in the MIUN gasifier increases the gasification efficiency, suppresses the tar generation and upgrades the syngas quality.
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| 2. |
- Göransson, Kristina, et al.
(författare)
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Experimental test on a novel dual fluidised bed biomass gasifier for synthetic fuel production
- 2011
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Ingår i: Fuel. - : Elsevier BV. - 0016-2361 .- 1873-7153. ; 90:4, s. 1340-1349
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Tidskriftsartikel (refereegranskat)abstract
- This article presents a preliminary test on the 150 kWth allothermal biomass gasifier at MIUN (Mid Sweden University) in Härnösand, Sweden. The MIUN gasifier is a combination of a fluidised bed gasifier and a CFB riser as a combustor with a design suitable for in-built tar/CH4 catalytic reforming. The test was carried out by two steps: 1) fluid-dynamic study; 2) measurements of gas composition and tar. A novel solid circulation measurement system which works at high bed temperatures is developed in the presented work. The results show the dependency of bed material circulation rate on the superficial gas velocity in the combustor, the bed material inventory and the aeration of solids flow between the bottoms of the gasifier and the combustor. A strong influence of circulation rate on the temperature difference between the combustor and the gasifier was identified. The syngas analysis showed that, as steam/biomass (S/B) ratio increases, CH4 content decreases and H2/CO ratio increases. Furthermore the total tar content decreases with increasing steam/biomass ratio and increasing temperature. The biomass gasification technology at MIUN is simple, cheap, reliable, and can obtain a syngas of high CO+H2concentration with sufficient high ratio of H2 to CO, which may be suitable for synthesis of Methane, DME, FT-fuels or alcohol fuels. The measurement results of MIUN gasifier have been compared with other gasifiers. The main differences can be observed in the H2 and the CO content, as well as the tar content. These can be explained by differences in the feed systems, operating temperature, S/B ratio or bed material catalytic effect etc..
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| 3. |
- Göransson, Kristina, et al.
(författare)
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Internal tar/CH4 reforming in a biomass dual fluidised bed gasifier
- 2014
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Ingår i: Proceeding of 4th International Symposium on Gasification and its Applications.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- An internal reformer is developed for in-situ catalytic reforming of tar and methane (CH4) in allothermal gasifiers. The study has been performed in the 150 kW dual fluidised bed (DFB) biomass gasifier at Mid Sweden University (MIUN). The MIUN gasifier is built for research on synthetic fuel production. Reduction of tars and CH4 (except for methanation application) in the syngas is a major challenge for commercialization of biomass fluidised-bed gasification technology towards automotive fuel production. The MIUN gasifier has a unique design with an internal reformer, where intensive contact of gas and catalytic solids improves the reforming reactions. This paper presents a study on the internal reformer operated with and without Ni-catalytic pellets, by evaluation of the syngas composition and tar/CH4 content. It can be concluded that the reformer with Ni-catalytic pellets clearly gives a higher H2 content together with lower CH4 and tar contents in the syngas than the reformer without Ni-catalytic pellets. The gravimetric tar content decreases down to 5 g/m3 and the CH4 content down below 6% in the syngas. The novel design in the MIUN gasifier increases the gasification efficiency, suppresses the tar generation and upgrades the syngas quality
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| 4. |
- Göransson, Kristina
(författare)
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Internal Tar/CH4 Reforming in Biomass Dual Fluidised Bed Gasifiers towards Fuel Synthesis
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Production of high-quality syngas from biomass gasification in a dual fluidised bed gasifier (DFBG) has made a significant progress in R&D and Technology demonstration. An S&M scale bio-automotive fuel plant close to the feedstock resources is preferable as biomass feedstock is widely sparse and has relatively low density, low heating value and high moisture content. This requires simple, reliable and cost-effective production of clean and good syngas. Indirect DFBGs, with steam as the gasification agent, produce a syngas of high content H2 and CO with 12-20 MJ/mn3 heating value. The Mid Sweden University (MIUN) gasifier, built for research on synthetic fuel production, is a dual fluidised bed gasifier. Reforming of tars and CH4 (except for methanation application) in the syngas is a major challenge for commercialization of biomass fluidised-bed gasification technology towards automotive fuel production. A good syngas from DFBGs can be obtained by optimised design and operation of the gasifier, by the use of active catalytic bed material and internal reforming. This thesis presents a series of experimental tests with different operation parameters, reforming of tar and CH4 with catalytic bed material and reforming of tar and CH4 with catalytic internal reformer. The first test was carried out to evaluate the optimal operation and performance of the MIUN gasifier. The test provides basic information for temperature control in the combustor and the gasifier by the bed material circulation rate. After proven operation and performance of the MIUN gasifier, an experimental study on in-bed material catalytic reforming of tar/CH4 is performed to evaluate the catalytic effects of the olivine and Fe-impregnated olivine (10%wtFe/olivine Catalyst) bed materials, with reference to non-catalytic silica sand operated in the mode of dual fluidised beds (DFB). A comparative experimental test is then carried out with the same operation condition and bed-materials but when the gasifier was operated in the mode of single bubbling fluidised bed (BFB). The behaviour of catalytic and non-catalytic bed materials differs when they are used in the DFB and the BFB. Fe/olivine and olivine in the BFB mode give lower tar and CH4 content together with higher H2+CO concentration, and higher H2/CO ratio, compared to DFB mode. It is hard to show a clear advantage of Fe/olivine over olivine regarding tar/CH4 catalytic reforming. In order to significantly reduce the tar/CH4 contents, an internal reformer, referred to as the FreeRef reformer, is developed for in-situ catalytic reforming of tar and CH4 using Ni-catalyst in an environment of good gas-solids contact at high temperature. A study on the internal reformer filled with and without Ni-catalytic pellets was carried out by evaluation of the syngas composition and tar/CH4 content. It can be concluded that the reformer with Ni-catalytic pellets clearly gives a higher H2 content together with lower CH4 and tar contents in the syngas than the reformer without Ni-catalytic pellets. The gravimetric tar content decreases from 25 g/m3 down to 5 g/m3 and the CH4 content from 11% down below 6% in the syngas. The MIUN gasifier has a unique design suitable for in-bed tar/CH4 catalytic reforming and continuously internal regeneration of the reactive bed material. The novel design in the MIUN gasifier increases the gasification efficiency, suppresses the tar generation and upgrades the syngas composition.
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| 5. |
- Göransson, Kristina, et al.
(författare)
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Internal Tar/CH4 Reforming using a Novel Design in a Biomass Dual Fluidised Bed Gasifier
- 2013
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Ingår i: 21st European Biomass Conference and Exhibition. - Florence, Italy : ETA-Florence Renewable Energies. - 9788889407530 ; , s. 2038-2042
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Reforming of tars and methane (CH4) in syngas is a significant challenge for low-temperature biomass gasification. For a dual fluidised bed gasifier (DFBG), catalytic bed materials are usually used to promote the reforming reactions. Intensive contact between gas and catalytic bed material at high temperature enhances the internal tar/CH4 reforming. The MIUN gasifier, built for research into synthetic fuel production, is a dual fluidised bed gasifier (DFBG). The results with different bed materials (silica sand, olivine and Fe-impregnated olivine) give roughly equivalent amounts of methane and gravimetric tar in the raw untreated syngas, and need to be reduced to an acceptably low level. The gasification research group at MIUN investigates a novel design in the MIUN gasifier, to increase the gasification efficiency, suppress the tar generation and to upgrade the syngas quality. The first step is taken towards a novel design in the MIUN gasifier. The application is expected to significantly enhance the syngas quality.
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| 6. |
- Göransson, Kristina, et al.
(författare)
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Review of syngas production via biomass DFBGs
- 2011
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Ingår i: Renewable & sustainable energy reviews. - : Elsevier BV. - 1364-0321 .- 1879-0690. ; 15:1, s. 482-492
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Forskningsöversikt (refereegranskat)abstract
- Production of high-quality syngas from biomass gasification in a dual fluidised bed gasifier (DFBG) has made a significant progress in R&D and Technology demonstration. An S&M scale bio-automotive fuel plant close to the feedstock resources is preferable as biomass feedstock is widely sparse and has relatively low density, low heating value and high moisture content. This requires a simple, reliable and cost-effective production of clean and good quality syngas. Indirect DFBGs, with steam as the gasification agent, produces a syngas of high content H2 and CO with 12-20 MJ/mn3 heating value. A good quality syngas from DFBGs can be obtained by optimised design and operation of the gasifier, by the use of active catalytic bed materials including internal reforming of tars and methane, and finally by a downstream cleaning process. This article reviews the whole process from gasification to high quality syngas. © 2010 Elsevier Ltd. All rights reserved.
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| 7. |
- Göransson, Kristina, et al.
(författare)
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Tar/CH4 Reforming by Catalytic Bed Materials in a Biomass Fluidised Bed Gasifier
- 2012
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Ingår i: 20th European Biomass Conference & Exhibition.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- A study on in-bed catalytic material reforming of tar/methane (CH4) has been performed in the 150 kW allothermal biomass gasifier at Mid Sweden University (MIUN). The MIUN gasifier, built for research on synthetic fuel production, is a dual fluidised bed gasifier (DFBG). The syngas for automotive fuels synthesis has a strict specification of impurities. The biggest challenge for biomass fluidised-bed gasification is the reforming of tars and CH4. Internal reforming should be considered before downstream reforming. The MIUN gasifier has a unique design suitable for in-bed tar/CH4 catalytic reforming and continuously internal regeneration of the reactive bed material. The experimental tests are carried out in three cases: 1) basic condition with silica sand (no catalytic activity), 2) calcinated olivine, and 3) Fe-impregnated olivine (10%wtFe/Olivine Catalyst). The measurement results have been evaluated by comparing tar/CH4 content in the syngas from the gasifier operated under different operation conditions. These results in BFB mode have initiated the ongoing investigations of the catalytic effects and regeneration in DFB mode. It can be concluded that the Fe-impregnated olivine showed a surprising low reactivity for tar and CH4 reforming in the BFB model.
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| 8. |
- Göransson, Kristina, et al.
(författare)
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TAR/CH4 REFORMING BY CATALYTICALLY ACTIVE MATERIALS IN A BIOMASS DUAL FLUIDISED BED GASIFIER
- 2010
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Ingår i: The second International Symposium on Gasification and Its Application (ISGA 2010), December 5-8, Fukuoka, Japan.
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Konferensbidrag (refereegranskat)abstract
- This paper presents a study on the effects of catalytically active materials, before tests in the 150 kW allothermal biomass gasifier at Mid Sweden University (MIUN). The gasifier has been built up in 2008 for research on synthetic fuel production, and is a combination of a circulating fluidised bed (CFB) riser as combustor and a fluidised bed (FB) as steam gasifier. The MIUN gasifier has a unique design suitable for in-built tar/methane (CH4) catalytic reforming. The lifetime of the catalyst can be prolonged using a dual fluidised bed gasifier (DFBG) with continuously internal regeneration of the catalyst. The catalytic effects of 1) basic condition with silica sand (no catalytic activity), 2) commercial catalyst, 3) development metal-catalyst (high surface area support), and 4) olivine catalyst will be evaluated by comparing tar/CH4 content in the syngas from the gasifier operated under different conditions. Silica sand and commercial catalyst can be considered as extremes for comparing the activity of the chosen conditions.
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| 9. |
- He, Jie, et al.
(författare)
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Bio-SNG production in a TMP Mill in comparison with BIGCC
- 2014
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Ingår i: Energy Procedia. - : Elsevier. - 1876-6102. ; , s. 2894-2897
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Konferensbidrag (refereegranskat)abstract
- Biorefinery as a concept for polygeneration of various bio-based materials, fuels and chemicals has been more and more attractive. This concept is applied to the thermomechanical pulp (TMP) and paper industry in the present study to evaluate the possibility of co-production of substitute natural gas (SNG), electricity and district heating (DH) in addition to mechanical pulp and paper. In TMP mills, wood and biomass residues are commonly utilized for electricity and steam production through an associated combined heat and power (CHP) plant. This CHP plant is designed to be replaced by a biomass-T o-SNG (BtSNG) plant including an associated heat and power centre. Implementing BtSNG in a mechanical pulp production line might improve the profitability of a TMP mill and also help to commercialize the BtSNG technology by taking into account of some key issues such as, biomass availability, heat utilization etc. A TMP+BtSNG mathematical model is developed with ASPEN Plus.
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| 10. |
- He, Jie
(författare)
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Gasification-based Biorefinery for Mechanical Pulp Mills
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The modern concept of “biorefinery” is dominantly based on chemical pulp mills to create more value than cellulose pulp fibres, and energy from the dissolved lignins and hemicelluloses. This concept is characterized by the conversion of biomass into various bio-based products. It includes thermochemical processes such as gasification and fast pyrolysis. In thermo-mechanical pulp (TMP) mills, the feedstock available to the gasification-based biorefinery is significant, including logging residues, bark, fibre material rejects, bio-sludges and other available fuels such as peat, recycled wood and paper products. On the other hand, mechanical pulping processes consume a great amount of electricity, which may account for up to 40% of the total pulp production cost. The huge amount of purchased electricity can be compensated for by self-production of electricity from gasification, or the involved cost can be compensated for by extra revenue from bio-transport fuel production. This work is to study co-production of bio-automotive fuels, bio-power, and steam via gasification of the waste biomass streams in the context of the mechanical pulp industry. Ethanol and substitute natural gas (SNG) are chosen to be the bio-transport fuels in the study. The production processes of biomass-to-ethanol, SNG, together with heat and power, are simulated with Aspen Plus. Based on the model, the techno-economic analysis is made to evaluate the profitability of bio-transport fuel production when the process is integrated into a TMP mill.The mathematical modelling starts from biomass gasification. Dual fluidized bed gasifier (DFBG) is chosen for syngas production. From the model, the yield and composition of the syngas and the contents of tar and char can be calculated. The model has been evaluated against the experimental results measured on a 150KWth Mid Sweden University (MIUN) DFBG. As a reasonable result, the tar content in the syngas decreases with the gasification temperature and the steam to biomass (S/B) ratio. The biomass moisture content is a key parameter for a DFBG to be operated and maintained at a high gasification temperature. The model suggests that it is difficult to keep the gasification temperature above 850 ℃ when the biomass moisture content is higher than 15.0 wt.%. Thus, a certain amount of biomass or product gas needs to be added in the combustor to provide sufficient heat for biomass devolatilization and steam reforming.For ethanol production, a stand-alone thermo-chemical process is designed and simulated. The techno-economic assessment is made in terms of ethanol yield, synthesis selectivity, carbon and CO conversion efficiencies, and ethanol production cost. The calculated results show that major contributions to the production cost are from biomass feedstock and syngas cleaning. A biomass-to-ethanol plant should be built over 200 MW.In TMP mills, wood and biomass residues are commonly utilized for electricity and steam production through an associated CHP plant. This CHP plant is here designed to be replaced by a biomass-integrated gasification combined cycle (BIGCC) plant or a biomass-to-SNG (BtSNG) plant including an associated heat & power centre. Implementing BIGCC/BtSNG in a mechanical pulp production line might improve the profitability of a TMP mill and also help to commercialize the BIGCC/BtSNG technologies by taking into account of some key issues such as, biomass availability, heat utilization etc.. In this work, the mathematical models of TMP+BIGCC and TMP+BtSNG are respectively built up to study three cases: 1) scaling of the TMP+BtSNG mill (or adding more forest biomass logging residues in the gasifier for TMP+BIGCC); 2) adding the reject fibres in the gasifier; 3) decreasing the TMP SEC by up to 50%.The profitability from the TMP+BtSNG mill is analyzed in comparison with the TMP+BIGCC mill. As a major conclusion, the scale of the TMP+BIGCC/BtSNG mill, the prices of electricity and SNG are three strong factors for the implementation of BIGCC/BtSNG in a TMP mill. A BtSNG plant associated to a TMP mill should be built in a scale above 100 MW in biomass thermal input. Comparing to the case of TMP+BIGCC, the NR and IRR of TMP+BtSNG are much lower. Political instruments to support commercialization of bio-transport fuel are necessary.
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