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| 2. |
- Albertazzi, S, et al.
(författare)
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The technical feasibility of biomass gasification for hydrogen production
- 2005
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Ingår i: Catalysis Today. - : Elsevier BV. - 0920-5861 .- 1873-4308. ; 106:1-4, s. 297-300
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Tidskriftsartikel (refereegranskat)abstract
- Biomass gasification for energy or hydrogen production is a field in continuous evolution, due to the fact that biomass is a renewable and CO2 neutral source. The ability to produce biomass-derived vehicle fuel on a large scale will help to reduce greenhouse gas and pollution, increase the security of European energy supplies, and enhance the use of renewable energy. The Varnamo, Biomass Gassification Centre in Sweden is a unique plant and an important site for the development of innovative technologies for biomass transformation. At the moment, the Varnamo plant is the heart of the CHRISGAS European project, that aims to convert the produced gas for further upgrading to liquid fuels as dimethyl ether (DME), methanol or Fischer-Tropsch (F-T) derived diesel. The present work is an attempt to highlight the conditions for the reforming unit and the problems related to working with streams having high contents of sulphur and alkali metals.
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| 4. |
- Brandin, Jan, et al.
(författare)
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Bio-propane from glycerol for biogas addition
- 2008
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- In this report, the technical and economical feasibility to produce higher alkanes from bio-glycerol has been investigated. The main purpose of producing this kind of chemicals would be to replace the fossil LPG used in upgraded biogas production. When producing biogas and exporting it to the natural gas grid, the Wobbe index and heating value does not match the existing natural gas. Therefore, the upgraded biogas that is put into the natural gas grid in Sweden today contains 8-10 vol-% of LPG. The experimental work performed in association to this report has shown that it is possible to produce propane from glycerol. However, the production of ethane from glycerol may be even more advantageous. The experimental work has included developing and testing catalysts for several intermediate reactions. The work was performed using different micro-scale reactors with a liquid feed rate of 18 g/h. The first reaction, independent on if propane or ethane is to be produced, is dehydration of glycerol to acrolein. This was showed during 60 h on an acidic catalyst with a yield of 90%. The production of propanol, the second intermediate to producing propane, was shown as well. Propanol was produced both using acrolein as the starting material as well as glycerol (combining the first and second step) with yields of 70-80% in the first case and 65-70% in the second case. The propanol produced was investigated for its dehydration to propene, with a yield of 70-75%. By using a proprietary, purposely developed catalyst the propene was hydrogenated to propane, with a yield of 85% from propanol. The formation of propane from glycerol was finally investigated, with an overall yield of 55%. The second part of the experimental work performed investigated the possibilities of decarbonylating acrolein to form ethane. This was made possible by the development of a proprietary catalyst which combines decarbonylation and water-gas shift functionality. By combining these two functionalities, no hydrogen have to be externally produced which is the case of the propane produced. The production of ethane from acrolein was shown with a yield of 75%, while starting from glycerol yielded 65-70% ethane using the purposely developed catalyst. However, in light of this there are still work to be performed with optimizing catalyst compositions and process conditions to further improve the process yield. The economic feasibility and the glycerol supply side of the proposed process have been investigated as well within the scope of the report. After an initial overview of the glycerol supply, it is apparent that at least the addition of alkanes to biogas can be saturated by glycerol for the Swedish market situation at the moment and for a foreseeable future. The current domestic glycerol production would sustain the upgraded biogas industry for quite some time, if necessary. However, from a cost standpoint a lower grade glycerol should perhaps be considered. In the cost aspect, three different configurations have been compared. The three alternatives are ethane production, propane production with internal hydrogen supply and propane production with external hydrogen supply. The results from the base case calculations can be viewed in table ES1. The base case calculations are based on carburating the upgraded biogas, before introducing it to the natural gas grid, from a 24 GWh biogas production facility. This means that the production units supply an acceptable Wobbe index of the final upgraded biogas. The annual cost in table ES1 is the yearly cost of carburating the gas at a 24 GWh biogas site. From the base case, it is obvious that there are differences in glycerol consumption depending on what alternative is chosen. There are also investment cost differences. To further investigate the volatility of the prices, a blend of Monte Carlo techniques were used to generate multiple data sets. The conclusions from the simulations were that the ethane producing facility has a stronger dependence on the feedstock; it is hence more sensitive to changes in the feedstock cost. It is however not as sensitive to changes in investment cost. If the production cost is compared to the cost of fossil LPG used today, the cost of the LPG is 0.43 kr/kWh. This does however not include the taxation and transporting the fuel. Adding the taxation alone will put an additional 0.25 kr/kWh on the cost, totalling 0.68 kr/kWh. This compares well with the calculated production cost of 0.78 kr/kWh for ethane and with the 50% percentile acquired from the Monte Carlo simulations of 0.94 kr/kWh.
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| 10. |
- Brandin, Jan, 1958-
(författare)
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Preferential CO oxidation by mounted and un-mounted precious metal based catalyst
- 2005
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Ingår i: International journal of hydrogen energy. - : Elsevier. - 0360-3199 .- 1879-3487. ; 30:11, s. 1235-1242
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Tidskriftsartikel (refereegranskat)abstract
- A number of different noble metal catalysts were studied for activity in the preferential oxidation of carbon monoxide in hydrogen-rich streams. The prepared catalysts had an active phase of platinum, palladium, iridium, ruthenium or rhodium impregnated either directly on an aluminia matrix or mounted on nickel or cobalt oxide. The catalysts were studied for activity, but also for the reversed water gas shift side reaction. The most active catalyst was platinum mounted on cobalt oxide and it was studied closely. The platinum on the cobalt oxide was studied using STEM with XEDS and the effects of the platinum cluster size were investigated. Via microscopy it was possible to show that platinum had no preference for either alumina or cobalt. The activity increased with increasing platinum cluster size but the selectivity passed through a maximum, a probable deactivation mechanism to the catalyst on stream, showed on a 1,000 h deactivated sample.
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| 11. |
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| 12. |
- Einvall, Jessica, et al.
(författare)
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Investigation of reforming catalyst deactivation by exposure to fly ash from biomass gasification in laboratory scale
- 2007
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Ingår i: Energy & Fuels. - : American Chemical Society (ACS). - 0887-0624 .- 1520-5029. ; 21:5, s. 2481-2488
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Tidskriftsartikel (refereegranskat)abstract
- Production of synthesis gas by catalytic reforming of product gas from biomass gasification can lead to catalyst deactivation by the exposure to ash compounds present in the flue gas. The impact of fly ash from biomass gasification on reforming catalysts was studied at the laboratory scale. The investigated catalyst was Pt/Rh based, and it was exposed to generated K2SO4 aerosol particles and to aerosol particles produced from the water-soluble part of biomass fly ash, originating from a commercial biomass combustion plant. The noble metal catalyst was also compared with a commercial Ni-based catalyst, exposed to aerosol particles of the same fashion. To investigate the deactivation by aerosol particles, a flow containing submicrometer-size selected aerosol particles was led through the catalyst bed. The particle size of the poison was measured prior to the catalytic reactor system. Fresh and aerosol particle exposed catalysts were characterized using BET surface area, XRPD (X-ray powder diffraction), and H2 chemisorption. The Pt/Rh catalyst was also investigated for activity in the steam methane reforming reaction. It was found that the method to deposit generated aerosol particles on reforming catalysts could be a useful procedure to investigate the impact of different compounds possibly present in the product gas from the gasifier, acting as potential catalyst poisons. The catalytic deactivation procedure by exposure to aerosol particles is somehow similar to what happens in a real plant, when a catalyst bed is located subsequent to a biomass gasifier or a combustion boiler. Using different environments (oxidizing, reducing, steam present, etc.) in the aerosol generation adds further flexibility to the suggested aerosol deactivation method. It is essential to investigate the deactivating effect at the laboratory scale before a full-scale plant is taken into operation to avoid operational problems.
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| 13. |
- Hulteberg, Christian, et al.
(författare)
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Fuel Production From Gasified Biomass-A Feasibility Study
- 2006
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Ingår i: World bioenergy 2006 : taking you from know-how to show-how, 30 May-1 June 2006, Jönköping, proceedings. - 9163189607 ; , s. 308-314
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Konferensbidrag (refereegranskat)abstract
- To produce fuel from gasified biomass is a way to manufacture carbon dioxide neutral fuels for transport purposes. The biomass is gasified by heat in a gasification unit, with or without nitrogen, and the resulting mixture consist of hydrogen, carbon dioxide, carbon monoxide, methane, steam, higher hydrocarbons in low concentration and tars. The gas will also contain nitrogen, argon, ammonia, hydrogen sulphide and carbonyl sulphide. This gas mixture can be treated and upgraded in various ways depending on what fuel is the desired product. To increase the hydrogen content a reforming reactor can be added. This reactor will enhance the reaction between methane and higher hydrocarbons with steam or oxygen producing additional carbon monoxide, carbon dioxide and hydrogen. Two ways to do this is by using catalytic conversion or by thermal reforming. In the first case a catalyst is used and the yield is higher but there are problems associated with catalyst deactivation by sulphur, alkaline metals, heavy metals etc. In the thermal reforming the temperature is raised by adding oxygen to the gas and at the elevated temperature the equilibrium concentration of methane is low. This approach is less sensitive to poisoning but has a lower overall yield. The reformed gas or the gas leaving the gasifier is fed to a water-gas-shift reactor which adjusts the ratio between carbon monoxide and hydrogen. This ratio is decided depending on the desired fuel, 2 for DME, MeOH and Fischer Tropsch. This paper investigates various approaches to producing fuels from biomass through gasification, investigating such things as chemically bound energy and co-production of fuels. The various methods will be looked into and advantages and disadvantages will be compared. There will be no attempt to suggest any optimal method for fuel production from biomass through gasification since every case is unique regarding available biomass and desired fuels. Various ways to produce different fuels and the efficiency to chemically bound energy will be reported as will the effects of co-production of fuels. The results show that a catalytic reforming outperforms a thermal reforming and that co-production of fuels is beneficial.
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| 15. |
- Häggblad, Robert, et al.
(författare)
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Stabilization and regeneration of CeO2 and CeO2/ZrO2 based Pt catalyst for the water gas shift reaction
- 2005
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Ingår i: COM2005. - Montréal : Canadian Institute of Mining, Metallurgy and Petroleum. - 1894475615 ; , s. 641-655
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Konferensbidrag (refereegranskat)abstract
- The article deals with stabilisation and regeneration of CeO2 and CeO2/ZrO2 based Pt water gas shift catalysts, subject to high initial deactivation. The reaction gas species effect on the catalyst deactivation was investigated by H2-TPR. Activity measurements enabled the effect of different promoters, some added to the CeO2 based catalysts and some to the CeO2/ZrO2 based Pt catalysts, to be investigated. The catalysts were also characterised by BET and CO-TPR. Deactivated catalysts activity was restored by using various regeneration methods. Of the two selected carriers the CeO2/ZrO2 based Pt catalyst showed the highest resilience to deactivation. For the two different carriers, CeO2 and CeO2/ZrO2, W and Re were the best promoters when the catalyst was subject to deactivation. Experiments with H2-TPR indicate a fast initial change in the platinum oxides concentration and composition. The CO-TPR was used to make conclusions about the various regeneration effects of water and oxygen on the catalyst. Finally it is suggested that not one deactivation mechanism is possible and which mechanism that dominates is dependant on the catalyst and the reaction gas composition. (Less)
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| 16. |
- Kirm, Ilham, et al.
(författare)
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Shift catalysts in biomass generated synthesis gas
- 2007
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Ingår i: Topics in catalysis. - : Springer verlag. - 1022-5528 .- 1572-9028. ; 45:1-4, s. 31-37
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Tidskriftsartikel (refereegranskat)abstract
- One of the CHRISGAS project objectives is to study the shift catalysts in biomass-generated synthesis gas. The water gas shift reaction is ruled by equilibrium, and the state of the gas can for a given H2/CO ratio be shifted by addition/removal of water, CO2 and/or by a change in the temperature. Stability area in respect to gas composition, sulphur content, pressure and temperature for FeCr shift catalyst has been investigated by thermodynamic equilibrium calculations. The calculations show that carbide formation is favourable in the “Normal water” case without sulphur in the gas. If sulphur is present in the gas, the situation improves due to sulphide formation.
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| 17. |
- Prisell, Erik, et al.
(författare)
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A STUDY OF AN USER AND ENVIRONMENTAL FRIENDLY STORED ENERGY BASED EPU/APU-SYSTEM FOR MILITARY AEROSPACE APPLICATIONS
- 2008
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Ingår i: ICAS 2008. ; CD
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Konferensbidrag (refereegranskat)abstract
- Modern military multi-role combat aircrafts need an emergency power system (EPU) to maintain back-up power supply for all normal and degraded flight modes. The reason for this requirement is that modern combat aircrafts are designed with built-in relaxed or negative stability. Inability of the Flight Control System to perform continuous, corrective control surface actuation, due to loss of power supply or other causes implies instantaneous departure with loss of A/C. An emergency system needs to have a quick response and provide high power, electrical or hydraulic or combined, to a low weight and volume for considered time Different EPU systems have been tried over the years, hydrazine (monopropellant) driven turbines, compressed air and all-electric battery systems are dominating in existing applications. Gas generator systems however show advantages, but hydrazine for example is both toxic and carcenogenic. The operation of coming electrical weapons demands short bursts of very high power. The requirement of power, from this emerging field of applications, is conveniently fulfilled by tailoring of the EPU/APU systems approach. A small stored energy based system can also be the power source solution for electrical weapons in medium UAV’s. FMV has since 1999 performed a study of an EPU system based on stored energy together with a turbine solution. A novel gas generator system has been developed and demonstrated which is both a user and environmental friendly. The work-performing gas is generated from catalytically enabled and supported combustion of medium concentration hydrogen peroxide and methanol. The concept was evaluated by performing a feasibility study in three phases between 1999 and 2007. This paper will present the work performed and results from these three phases. The paper covers both the results from initial studies of different EPU system concepts/solutions and from the demonstrator programs of two turbine concepts where the second concept also incorporated a working novel hydrogen peroxide/methanol gas generator. Specific focus will be given to this novel gas generator concept which operates with a mixture of medium concentration hydrogen peroxide and methanol. The hydrogen peroxide is catalytically decomposed into steam/water and free oxygen that are used to combust the added methanol by a combustion catalyst into a high temperature ( ~600 C) working gas.
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