| 1. |
- Brandin, Jan, 1958-, et al.
(author)
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A review of thermo-chemical conversion of biomass into biofuels-focusing on gas cleaning and up-grading process steps
- 2017
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Reports (other academic/artistic)abstract
- It is not easy to replace fossil-based fuels in the transport sector, however, an appealing solution is to use biomass and waste for the production of renewable alternatives. Thermochemical conversion of biomass for production of synthetic transport fuels by the use of gasification is a promising way to meet these goals.One of the key challenges in using gasification systems with biomass and waste as feedstock is the upgrading of the raw gas produced in the gasifier. These materials replacing oil and coal contain large amounts of demanding impurities, such as alkali, inorganic compounds, sulphur and chlorine compounds. Therefore, as for all multi-step processes, the heat management and hence the total efficiency depend on the different clean-up units. Unfortunately, the available conventional gas filtering units for removing particulates and impurities, and also subsequent catalytic conversion steps have lower optimum working temperatures than the operating temperature in the gasification units.This report focuses on on-going research and development to find new technology solutions and on the key critical technology challenges concerning the purification and upgrading of the raw gas to synthesis gas and the subsequent different fuel synthesis processes, such as hot gas filtration, clever heating solutions and a higher degree of process integration as well as catalysts more resistant towards deactivation. This means that the temperature should be as high as possible for any particular upgrading unit in the refining system. Nevertheless, the temperature and pressure of the cleaned synthesis gas must meet the requirements of the downstream application, i.e. Fischer-Tropsch diesel or methanol.Before using the gas produced in the gasifier a number of impurities needs to be removed. These include particles, tars, sulphur and ammonia. Particles are formed in gasification, irrespective of the type of gasifier design used. A first, coarse separation is performed in one or several cyclone filters at high temperature. Thereafter bag-house filters (e.g. ceramic or textile) maybe used to separate the finer particles. A problem is, however, tar condensation in the filters and there is much work performed on trying to achieve filtration at as high a temperature as possible.The far most stressed technical barriers regarding cleaning of the gases are tars. To remove the tar from the product gas there is a number of alternatives, but most important is that the gasifier is operated at optimal conditions for minimising initial tar formation. In fluid bed and entrained flow gasification a first step may be catalytic tar cracking after particle removal. In fluid bed gasification a catalyst, active in tar cracking, may be added to the fluidising bed to further remove any tar formed in the bed. In this kind of tar removal, natural minerals such as dolomite and olivine, are normally used, or catalysts normally used in hydrocarbon reforming or cracking. The tar can be reformed to CO and hydrogen by thermal reforming as well, when the temperature is increased to 1300ºC and the tar decomposes. Another method for removing tar from the gas is to scrub it by using hot oil (200-300ºC). The tar dissolves in the hot oil, which can be partly regenerated and the remaining tar-containing part is either burned or sent back to the gasifier for regasification.Other important aspects are that the sulphur content of the gas depends on the type of biomass used, the gasification agent used etc., but a level at or above 100 ppm is not unusual. Sulphur levels this high are not acceptable if there are catalytic processes down-stream, or if the emissions of e.g. SO2 are to be kept down. The sulphur may be separated by adsorbing it in ZnO, an irreversible process, or a commercially available reversible adsorbent can be used. There is also the possibility of scrubbing the gas with an amine solution. If a reversible alternative is chosen, elementary sulphur may be produced using the Claus process.Furthermore, the levels of ammonia formed in gasification (3,000 ppm is not uncommon) are normally not considered a problem. When combusting the gas, nitrogen or in the worst case NOx (so-called fuel NOx) is formed; there are, however, indications that there could be problems. Especially when the gasification is followed by down-stream catalytic processes, steam reforming in particular, where the catalyst might suffer from deactivation by long-term exposure to ammonia.The composition of the product gas depends very much on the gasification technology, the gasifying agent and the biomass feedstock. Of particular significance is the choice of gasifying agent, i.e. air, oxygen, water, since it has a huge impact on the composition and quality of the gas, The gasifying agent also affects the choice of cleaning and upgrading processes to syngas and its suitability for different end-use applications as fuels or green chemicals.The ideal upgraded syngas consists of H2 and CO at a correct ratio with very low water and CO2 content allowed. This means that the tars, particulates, alkali salts and inorganic compounds mentioned earlier have to be removed for most of the applications. By using oxygen as the gasifying agent, instead of air, the content of nitrogen may be minimised without expensive nitrogen separation.In summary, there are a number of uses with respect to produced synthesis gas. The major applications will be discussed, starting with the production of hydrogen and then followed by the synthesis of synthetic natural gas, methanol, dimethyl ether, Fischer-Tropsch diesel and higher alcohol synthesis, and describing alternatives combining these methods. The SNG and methanol synthesis are equilibrium constrained, while the synthesis of DME (one-step route), FT diesel and alcohols are not. All of the reactions are exothermal (with the exception of steam reforming of methane and tars) and therefore handling the temperature increase in the reactors is essential. In addition, the synthesis of methanol has to be performed at high pressure (50-100 bar) to be industrially viable.There will be a compromise between the capital cost of the whole cleaning unit and the system efficiency, since solid waste, e.g. ash, sorbents, bed material and waste water all involve handling costs. Consequently, installing very effective catalysts, results in unnecessary costs because of expensive gas cleaning; however the synthesis units further down-stream, especially for Fischer-Tropsch diesel, and DME/methanol will profit from an effective gas cleaning which extends the catalysts life-time. The catalyst materials in the upgrading processes essentially need to be more stable and resistant to different kinds of deactivation.Finally, process intensification is an important development throughout chemical industries, which includes simultaneous integration of both synthesis steps and separation, other examples are advanced heat exchangers with heat integration in order to increase the heat transfer rates. Another example is to combine exothermic and endothermic reactions to support reforming reactions by using the intrinsic energy content. For cost-effective solutions and efficient application, new solutions for cleaning and up-grading of the gases are necessary.
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| 2. |
- Brandin, Jan, 1958-, et al.
(author)
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Aerosolkatalysatorer för industriell gasrening
- 2016
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Reports (peer-reviewed)abstract
- Aerosol catalysts – small particles (with aerodynamic diameter up to 100 m) of catalytically active material suspended in gas – were examined for the intended use of NOx reduction with ammonia (SCR) in smaller industrial plants and boilers as an alternative to SNCR. The aerosol particles are intended to be injected into the flue gas at high temperature, together with ammonia/urea, and then separated on a particulate filter (bag‐type filter) at low temperature. The NOx reduction can occur during the pneumatic transport in the boiler or/and on the catalytically active filter cake. The catalysts must have sufficiently high activity in order to keep down their consumption, they must be cheap enough to be used as a consumable item, and must be harmless to humans and the environment. Two materials were developed during the work as possible candidates: natural zeolites and a FeSO4/activated carbon‐based catalyst. Cost estimates, for a hypothetical 1 MWth plant, shows that a NOx reduction close to 50% economically justify the introduction of SNCR for small plants (<25 GWh, NOx reductions levels between 30‐50% and 2 in stoichiometric ratio), both for the use of urea and liquid anhydrous ammonia with the percent NOx fee of 50 SEK/kg. The result is modest, at best 15‐20% cost reduction compared to no action. Raised tariffs to 60 SEK/kg NOx will improved the situation, but the results are still modest. When the aerosol catalysts was used in the cost estimate, and an assumed NOx reduction degree of 85% was supposed to be reached, good results were obtained at low catalyst costs (0.5‐2 SEK/kg). However the plant can handle at most a cost of 4 SEK/kg. Estimated cost for the aerosol catalyst is in the range of 10 SEK/kg. In order to be economically attractive, the catalyst should be recycled, thereby lowering the cost of catalyst consumption.
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| 3. |
- Brandin, Jan, 1958-, et al.
(author)
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Deactivation and Characterization of SCR Catalysts Used in Municipal Waste Incineration Applications
- 2018
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In: Catalysis Letters. - : Springer. - 1011-372X .- 1572-879X. ; 148:1, s. 312-327
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Journal article (peer-reviewed)abstract
- Catalysts used for selective catalytic reduction were deactivated for various times in a slipstream from a municipal solid waste incineration plant and then characterized. The activity for NO reduction with NH3 was measured. The Brunauer–Emmett–Teller surface areas were determined by N2 adsorption from which the pore size distributions in the mesopore region were obtained. Micropore areas and volumes were also obtained. The composition of fresh and deactivated catalysts as well as fly ash was determined by atomic absorption spectroscopy and scanning electron microscopy with energy dispersive X-ray analysis. The changes in surface area (8% decrease in BET surface area over 2311 h) and pore structure were small, while the change in activity was considerable. The apparent pre-exponential factor was 1.63 × 105 (1/min) in the most deactivated catalyst, compared to 2.65 × 106 (1/min) in the fresh catalyst, i.e. a reduction of 94%. The apparent activation energy for the fresh catalyst was 40 kJ/mol, decreasing to 27 kJ/mol with increasing deactivation. Characterization showed that catalytic poisoning is mainly due to decreased acidity of the catalyst caused due to increasing amounts of Na and K.
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| 4. |
- Brandin, Jan, 1958-, et al.
(author)
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Poisoning of SCR Catalysts used in Municipal Waste Incineration Applications
- 2017
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In: Topics in catalysis. - : Springer. - 1022-5528 .- 1572-9028. ; 60:17-18, s. 1306-1316
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Journal article (peer-reviewed)abstract
- A commercial vanadia, tungsta on titania SCRcatalyst was poisoned in a side stream in a waste incinerationplant. The effect of especially alkali metal poisoning was observed resulting in a decreased activity at long times of exposure. The deactivation after 2311 h was 36% whilet he decrease in surface area was only 7.6%. Thus the major cause for deactivation was a chemical blocking of acidic sites by alkali metals. The activation–deactivation model showed excellent agreement with experimental data. The model suggests that the original adsorption sites, from the preparation of the catalyst, are rapidly deactivated but are replaced by a new population of adsorption sites due to activation of the catalyst surface by sulphur compounds (SO2, SO3) in the flue gas.
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| 5. |
- Gavrilovic, Ljubisa, et al.
(author)
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Deactivation of Co-based Fischer-Tropsch catalyst by aerosol deposition of potassium salts
- 2018
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In: Industrial & Engineering Chemistry Research. - Washington, USA : American Chemical Society (ACS). - 0888-5885 .- 1520-5045. ; 57:6, s. 1935-1942
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Journal article (peer-reviewed)abstract
- A 20%Co/0.5%Re/γAl2O3 Fischer-Tropsch catalyst was poisoned by four potassium salts (KNO3, K2SO4, KCl, K2CO3) using the aerosol deposition technique, depositing up to 3500 ppm K as solid particles. Standard characterization techniques (H2 Chemisorption, BET, TPR) showed no difference between treated samples and their unpoisoned counterpart. The Fischer-Tropsch activity was investigated at industrially relevant conditions (210 °C, H2:CO = 2:1, 20 bar). The catalytic activity was significantly reduced for samples exposed to potassium, and the loss of activity was more severe with higher potassium loadings, regardless of the potassium salt used. A possible dual deactivation effect by potassium and the counter-ion (chloride, sulfate) is observed with the samples poisoned by KCl and K2SO4. The selectivity towards heavier hydrocarbons (C5+) was slightly increased with increasing potassium loading, while the CH4 selectivity was reduced for all the treated samples. The results support the idea that potassium is mobile under FT conditions. The loss of activity was described by simple deactivation models which imply a strong non-selective poisoning by the potassium species.
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| 6. |
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| 7. |
- Gavrilovic, Ljubisa, et al.
(author)
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Fischer-Tropsch synthesis : Investigation of the deactivation of a Co catalyst by exposure to aerosol particles of potassium salt
- 2018
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In: Applied Catalysis B. - : Elsevier. - 0926-3373 .- 1873-3883. ; 230, s. 203-209
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Journal article (peer-reviewed)abstract
- The influence of potassium species on a Co based Fischer-Tropsch catalyst was investigated using an aerosol deposition technique. This way of poisoning the catalyst was chosen to simulate the actual potassium behaviour during the biomass to liquid (BTL) process utilizing gasification followed by fuel synthesis. A reference catalyst was poisoned with three levels of potassium and the samples were characterized and tested for the Fischer-Tropsch reaction under industrially relevant conditions. None of the conventional characterization techniques applied (H2 Chemisorption, BET, TPR) divulged any difference between poisoned and unpoisoned samples, whereas the activity measurements showed a dramatic drop in activity following potassium deposition. The results are compared to previous results where incipient wetness impregnation was used as the method of potassium deposition. The effect of potassium is quite similar in the two cases, indicating that irrespective of how potassium is introduced it will end up in the same form and on the same location on the active surface. This indicates that potassium is mobile under FTS conditions, and that potassium species are able to migrate to sites of particular relevance for the FT reaction.
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| 8. |
- Gavrilovic, Ljubisa, et al.
(author)
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Influence of potassium species on Co based Fischer-Tropsch-catalyst.
- 2016
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Conference paper (peer-reviewed)abstract
- 1. IntroductionThe purpose of this work is better understanding of the alkali influence on Co-based F-T catalyst. Since potassium is one of the elements that can be present in syngas from biomass[1], one of the questions is how potassium species affect the Co catalyst. From previous work it has been shown that alkali species act as poisons, thus deactivating catalysts[2]. Most previous work in this group[3][4] and by others[5] has concerned Co catalysts that were exposed to potassium species by incipient wetness impregnation, which is essentially different from the real behaviour during the gasification process where the species will mainly be in the vapor phase. In the present work we study potassium influence on a Co-based catalyst, using aerosol technology as a new method for potassium deposition on the Co surface. 2. Experimental4 different potassium salts were deposited using aerosol deposition on 20%Co/0.5%Re/γAl2O3. The amount of potassium salts deposited were determined using ICP analysis. Potassium salts were chosen from studies of the gases from biomass gasification[6]. These are K2SO4, KCl, KNO3 and K2CO3. KNO3 will be reduced to KOH during biomass gasification, but since in these experiments temperature was not so high and there was no H2/CO, most likely KNO3 will be deposited as such on the Co surface.BET N2 adsorption, H2 chemisorption, temperature programmed reduction (TPR) were used to characterize all the poisoned catalysts.Fischer Tropsch activity and selectivity measurements were performed at the in house build set-up, at 210°C, 20 bar and at H2:CO ratio of 2.1. The GHSV was consistently varied to maintain comparable CO conversion levels between 20-50%. A detailed description of the setup and procedures can be found elsewhere[3]. 3. ResultsThe potassium species were deposited using aerosol technology in the apparatus shown in Fig. 1. Potassium salts are dissolved in deionized water and the solution is placed inside the atomizer, which produces aerosol particles. Nitrogen is used as a carrier gas which forces aerosol particles in the reactor direction. Before entering the reactor, the gas mixture carrying the aerosol is passing the impaction vessel to remove large particles. The catalyst bed is placed in the middle of the reactor, which can be heated up to 800°C. The generated aerosol particles were physically characterized according to their electrical mobility using a scanning mobility particle sizer (SMPS) consisting of a differential mobility analyser (DMA) and a condensation particle counter (CPC)[7]. The three target concentrations of potassium salts, 200 ppm, 800 ppm and 4000 ppm, were monitored by the above-mentioned instruments.Results from characterization by elemental analysis, H2 chemisorption, BET surface area, TPR together with the results from the Fischer Tropsch synthesis i.e. CO conversion, selectivity, and activity will be compared with the same catalyst without any poison and also with previous results obtained from solution impregnation of the same poisons[8][3][9].4. DiscussionThe purpose of the work is to study how this procedure of poisoning Co catalyst with aerosol particles will affect catalyst performances during Fischer Tropsch reaction. Previous similar work on Ni catalyst in the SCR reaction using aerosol technology as a method of deposition, has proven loss in metallic surface area, decreasing of metal dispersion and severe reduction in the catalytic activity [7]. The idea is to develop a technique to transfer potassium species, and potentially other relevant impurities, in vapor phase to the catalyst surface. This new approach can to a great extent simulate behaviour during the real industrial process. The aerosol could better represent in situ poisoning and therefore give a more realistic picture of the effect of potassium. This knowledge will be useful for designing new BTL processes. 5. ConclusionAerosol technology was used as a new method for depositing potassium salts on the Co surface. Poisoned catalysts were tested in Fischer Tropsch synthesis reactor together with elemental analysis. Results are compared to the reference catalyst and with previous work which use IWI as poisoning method. 6. References[1] A. Norheim, D. Lindberg, J. E. Hustad, and R. Backman, Energy and Fuels, (2009)[2] E. S. Wangen, A. Osatiashtiani, and E. A. Blekkan, Top. Catal., (2011)[3] C. M. Balonek, A. H. Lillebø, S. Rane, E. Rytter, L. D. Schmidt, and A. Holmen, Catal. Letters, (2010)[4] E. A. Blekkan, A. Holmen, S. Vada, Acta Chem. Scand., (1993)[5] J. Gaube and H. F. Klein, Appl. Catal. A Gen., (126–132, 2008)[6] H. M. Westberg, M. Byström, and B. Leckner, Energy and Fuels, (18–28, 2003)[7] S. Albertazzi, F. Basile, J. Brandin, J. Einvall, G. Fornasari, C. Hulteberg, M. Sanati, F. Trifirò, and A. Vaccari, Biomass and Bioenergy, (2008)[8] A. H. Lillebø, E. Patanou, J. Yang, E. A. Blekkan, and A. Holmen, in Catalysis Today, (2013)[9] E. Patanou, A. H. Lillebø, J. Yang, D. Chen, A. Holmen, and E. A. Blekkan, Ind. Eng. Chem. Res., (2014)[10] J. Einvall, S. Albertazzi, C. Hulteberg, A. Malik, F. Basile, A. C. Larsson, J. Brandin, and M. Sanati, Energy and Fuels, (2007)
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| 9. |
- Gavrilovic, Lubisa, et al.
(author)
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The effect of aerosol-deposited ash components on a cobalt-based Fischer–Tropsch catalyst
- 2019
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In: Reaction Kinetics, Mechanisms and Catalysis. - : Springer. - 1878-5190 .- 1878-5204. ; 127:1, s. 231-240
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Journal article (peer-reviewed)abstract
- The effect of ash salts on Co-based Fisher–Tropsch catalysts was studied using an aerosol deposition technique. The major elements in the ash were found to be K, S and Cl. The ash was deposited on a calcined catalyst as dry particles with an average diameter of approx. 350 nm. The loading of ash particles was varied by varying the time of exposure to the particles in a gas stream. Catalyst characterization did not reveal significant differences in cobalt dispersion, reducibility, surface area, pore size, or pore volume between the reference and the catalysts with ash particles deposited. Activity measurements showed that following a short exposure to the mixed ash salts (30 min), there were no significant loss of activity, but a minor change in selectivity of the catalyst . Extended exposure (60 min) led to some activity loss and changes in selectivity. However, extending the exposure time and thus the amount deposited as evidenced by elemental analysis did not lead to a further drop in activity. This behavior is different from that observed with pure potassium salts, and is suggested to be related to the larger size of the aerosol particles deposited. The large aerosol particles used here were probably not penetrating the catalyst bed, and to some extent formed an external layer on the catalyst bed. The ash salts are therefore not able to penetrate to the pore structure and reach the Co active centers, but are mixed with the catalyst and detected in the elemental analysis.
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| 10. |
- Hulteberg, Christian, et al.
(author)
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Pore Condensation in Glycerol Dehydration : Modification of a Mixed Oxide Catalyst
- 2017
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In: Topics in catalysis. - : Springer. - 1022-5528 .- 1572-9028. ; 60:17-18, s. 1462-1472
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Journal article (peer-reviewed)abstract
- Pore condensation has been suggested as an initiator of deactivation in the dehydration of glycerol to acrolein. To avoid potential pore condensation of the glycerol, a series of WO3supported on ZrO2 catalysts have been prepared through thermal sintering, with modified pore systems. It was shown that catalysts heat treated at temperatures above 800 °C yielded suitable pore system and the catalyst also showed a substantial increase in acrolein yield. The longevity of the heat-treated catalysts was also improved, indeed a catalyst heat treated at 850 °C displayed significantly higher yields and lower pressure-drop build up over the 600 h of testing. Further, the catalyst characterisation work gave evidence for a transition from monoclinic to triclinic tungsten oxide between 850 and 900 °C. There is also an increase in acid-site concentration of the heat-treated catalysts. Given the improved catalyst performance after heat-treatment, it is not unlikely that pore condensation is a significant contributing factor in catalyst deactivation for WO3 supported on ZrO2 catalysts in the glycerol dehydration reaction.
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| 11. |
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| 12. |
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| 13. |
- Nørregård, Øyvind, et al.
(author)
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Catalyst choise and considerations in the conversion of Glucose to glycerol.
- 2016
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In: Proceedings of the 17th Nordic Symposium on Catalysis. ; , s. 204-206
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Conference paper (peer-reviewed)abstract
- Through the 20th century the use of glycerine has mainly been focused to the food industry, the cosmetic industry and the pharmaceutical industry. The required volumes for these industries can’t be compared with the larger bulk chemicals produced today. These low requirements together with the increased glycerine production, associated with the biodiesel production from which glycerine is a large by-product, has forced the prices down to approximately 100-150 $/tonne. This low cost crude glycerine has been an initiator for developing methods on how to convert the glycerine to more usable products. A proposed method by the company Biofuel Solutions has been to convert the glycerine into bio-LPG. With the EU directives stating that at least 10 % of the fuels in the transport sector should come from renewable sources this route may turn out favourable. This will though cause a large increase in demand as one of the few new ways to provide bio-LPG and thus increase in price, which will require new ways to produce glycerine.With a possible increased demand on glycerine a proposed route to produce glycerine is via catalytic hydrogenation of glucose to sorbitol and further catalytic hydrogenolysis of sorbitol to glycerine. The production of sorbitol from glucose is today already industrialised with large producers such as Roquette Frères, Cargill and SPI Polyols. The industrial process is historically made batch wise with low cost Raney-nickel catalyst but with the development of good selectivity catalysts with no leaching problems it is assumed that todays’ production is mainly operating with catalyst with noble metals as the active metal, such as ruthenium, in a continuous process. For the hydrogenolysis of sorbitol to glycerine a good method is rather unexplored as the hydrogenolysis is previously mostly performed with either ethylene glycol (EG) or propylene glycol (PG) as the wanted product [1]. In context with the text above it is of great interest to investigate the catalytic hydrogenolysis of sorbitol to glycerine for the further production of bio-LPG.Research made on catalytic hydrogenolysis of sorbitol is done with mostly glycols as the main products, [1]. With the still reasonable selectivity of glycerine, up to 40 % with Raney-nickel as catalyst [2], the proposed research method is similar [1-3]. The planned method performed by Biofuel-Solutions includes trials in an autoclave reactor with the catalyst dispersed in the reactant solution under hydrogen pressure of 20-100 bar and mild temperatures, 100-300 °C, and stirring in resemblance to previous research [4]. As leaching issues has been seen with Raney-nickel in the hydrogenation of glucose to produce sorbitol [5], a similar process, this behaviour is expected to require certain measures which also will be tested. Tests will also include to investigate the influence of the catalyst basicity, which seems to affect the selectivity towards glycerol positively [1,2,5].A final process of producing bio-LPG with the start from glucose is seen in Figure 1 below. In the picture a long chain of processes-steps is displayed. In the blue box the degradation of the lignocellulosic material takes place. This is then led to the fraction where glucose is required from enzymatic hydrolysis. In the grey box to the right the glycerol conversion to LPG is shown, a multi process-step of which most details are already known within the company.
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| 14. |
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| 15. |
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| 16. |
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| 17. |
- Parsland, Charlotte, et al.
(author)
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Nickel-substituted bariumhexaaluminates as novel catalysts in steam reforming of tars
- 2015
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In: Fuel processing technology. - : Elsevier. - 0378-3820 .- 1873-7188. ; 140, s. 1-11
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Journal article (peer-reviewed)abstract
- This work investigates the performance of Ba–Ni-hexaaluminate, BaNixAl12 − xO19, as a new catalyst in thesteam-reforming of tars. Substituted hexaaluminates are synthesized and characterized. Steam reforming testsare carried out with both a model-substance (1-methylnaphthalene) and a slip-stream from a circulatingfluidized bed gasifier. The water–gas-shift activity is studied in a lab-scale set-up. Barium–nickel substitutedhexaaluminates show a high catalytic activity for tar cracking, and also shows activity for water–gas-shift.
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| 18. |
- Tunå, Per, et al.
(author)
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Modelling of a reverse-flow partial oxidation reactor for synthesis gas production from gasifier product gas.
- 2015
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In: Journal of Computational Methods in Sciences and Engineering. - : IOS Press. - 1472-7978 .- 1875-8983. ; 15:3, s. 593-604
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Journal article (peer-reviewed)abstract
- Biomass gasification followed by fuel synthesis is one of the alternatives for producing liquid fuels and chemicalsfrom biomass feedstocks. The gas produced by gasification contains CO, H2, H2O, CO2, light hydrocarbons and tars. Thelight hydrocarbons can account for as much as 50% of the total energy content of the gas, depending on the type of gasifier,operating conditions and feedstock. The gas also contains catalyst poisons such as sulphur, in the form of H2S and COS. Thispaper presents simulations of a reverse-flow partial-oxidation reformer that converts the light hydrocarbons into more synthesisgas, while achieving efficiencies approaching that of conventional catalytic processes. Variations in parameters such as pressure,amount of oxidant and steam-to-carbon ratio were also investigated. Simulations of the reforming of natural gas were includedfor comparison. The results show the benefits of using reverse-flow operation with lean gases such as gasifier product gas.
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