| 1. |
- Brandin, Jan, 1958-, et al.
(författare)
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Selective Catalysts for Glycerol Dehydration
- 2013
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Ingår i: CRS-2, Catalysis for Renewable Sources. - Novosibirsk, Russia : Boreskov Institute of Catalysis. - 9785990255777 ; , s. 17-18
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Konferensbidrag (refereegranskat)abstract
- There has been an increased interest over the last decade for replacing fossil based feedstock’s with renewable ones. There are several such feedstock’s that are currently being investigated such as cellulose, lignin, hemicellulose, triglycerides etc. However, when trying to perform selective reactions an as homogeneous feedstock as possible is preferable. One such feedstock example is glycerol, a side-product from biofuels production, which is a tri-alcohol and thus has much flexibility for reactions, e.g. dehydration, hydrogenation, addition reactions etc. Glycerol in itself is a good starting point for fine chemicals production being non-toxic and available in rather large quantities [1-2]. A key reaction for glycerol valorisation is the dehydration of glycerol to form acrolein, an unsaturated C3 aldehyde, which may be used for producing acrylic acid, acrylonitrile and other important chemcial products. It has recently been shown that pore-condensation of glycerol is an issue under industrial like conditions, leading to liquid-phase reactions and speeding up the catalyst activity and selectivity loss [3]. To address this issue, modified catalyst materials have been prepared where the relevant micro and meso pores have been removed by thermal sintering; calculations have shown that pores below 45 Å may be subject to pore condensation. The catalyst starting material was a 10% WO3 by weight supported on ZrO2 in the form of beads 1–2 mm and it was thermally treated at 400°C, 500°C, 600°C, 700°C, 700°C, 800°C, 850°C, 900°C and 1000°C for 2 hours. The catalysts were characterised using nitrogen adsorption, mercury intrusion porosimetry (MIP), Raman spectroscopy and ammonia temperature programmed desorption. The thermal sintered catalysts show first of all a decreasing BET surface area with sintering commencing between 700°C and 800°C when it decreases from the initial 71 m2/g to 62 m2/g and at 1000°C there is a mere 5 m2/g of surface area left. During sintering, the micro and meso-porosity is reduced as evidenced by MIP and depicted in figure 1. As may be seen in the figure, sintering decrease the amount of pores below and around 100 Å is reduced at a sintering temperature of 800°C and above. The most suitable catalyst based on the MIP appears to be the one sintered at 850°C which is further strengthened by the Raman analysis. There is a clear shift in the tungsten structure from monoclinic to triclinic between 850°C and 900°C and it is believed that the monoclinic phase is important for activity and selectivity. Further, the heat treatment shows that there is an increase in catalyst acidity measured as mmol NH3/(m2/g) but a decrease in the acid strength as evidenced by a decrease in the desorption peak maximum temperature.
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| 2. |
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| 3. |
- Hulteberg, Christian, et al.
(författare)
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Demonstrating Renewable Propane
- 2018
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- There is a significant infrastructure in the world for using liquefiedpetroleum gas (LPG). The fuel is used in many applications, spanningfrom heating to chemical processes as well as a vehicle fuel. To be able touse this infrastructure also after a transition from fossil to renewablesources, a technology for producing LPG from such resources (glycerol,cellulose etc.) is being developed. This report summarize theconstruction and operation of a pilot plant converting glycerol into LPG.But also report the progress made in turning cellulose into a LPGfeedstock.
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| 4. |
- Hulteberg, Christian, et al.
(författare)
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Pore Condensation i Glycerol Dehydration
- 2013
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Ingår i: Topics in catalysis. - : Springer. - 1022-5528 .- 1572-9028. ; 56:9-10, s. 813-821
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Tidskriftsartikel (refereegranskat)abstract
- Pore condensation followed by polymerizationis proposed as an explanatory model of several observationsreported in the literature regarding the dehydration ofglycerol to acrolein. The major conclusion is that glycerolpore condensation in the micro- and mesopores, followedby polymerization in the pores, play a role in catalystdeactivation.
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| 5. |
- Hulteberg, Christian, et al.
(författare)
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Pore Condensation in Glycerol Dehydration : Modification of a Mixed Oxide Catalyst
- 2017
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Ingår i: Topics in catalysis. - : Springer. - 1022-5528 .- 1572-9028. ; 60:17-18, s. 1462-1472
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Tidskriftsartikel (refereegranskat)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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| 6. |
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| 7. |
- Hulteberg, Christian, et al.
(författare)
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Scaling up a Gas-Phase Process for Converting Glycerol to Propane
- 2020
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Ingår i: Catalysts. - : MDPI AG. - 2073-4344. ; 10:9
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Tidskriftsartikel (refereegranskat)abstract
- It is of interest to study not only the fundamental behavior of catalysts and reactors but also to ensure that they can be scaled up in size. This paper investigates the scale-up of a glycerol-to-propane process starting from fundamental laboratory data from micro-reactor testing to the kilogram scale. The process is described in detail and consist of the use of design documents and computer simulations for determining the sizes of the unit operations involved. The final design included a vaporizer section for a glycerol/water mixture, four reactors in tandem with subsequent dehydration and hydrogenation reactions, a flash vessel to separate the excess hydrogen used, and a compressor for recycling the excess hydrogen with additional light components. The system was commissioned in a linear fashion, which is described, and operated for more than 3000 h and more than 1000 h in the final operating mode including recycle. The major results were that no catalyst deactivation was apparent aside from the slow build-up of carbonaceous material in the first dehydration reactor. That the system design calculations proved to be quite close to the results achieved and that the data generated is believed to be sufficient for up-scaling the process into the 1000 to 10,000 tonnes-per-annum range.
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| 8. |
- Nørregård, Øyvind, et al.
(författare)
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Catalyst choise and considerations in the conversion of Glucose to glycerol.
- 2016
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Ingår i: Proceedings of the 17th Nordic Symposium on Catalysis. ; , s. 204-206
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Konferensbidrag (refereegranskat)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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