| 1. |
- Basile, Francesco, et al.
(författare)
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Steam reforming of hot gas from gasified wood types and miscanthus biomass
- 2011
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Ingår i: Biomass and Bioenergy. - : Elsevier. - 0961-9534 .- 1873-2909. ; 35:Supplement 1, s. S116-S122
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Tidskriftsartikel (refereegranskat)abstract
- The reforming of hot gas generated from biomass gasification and high temperature gas filtration was studied in order to reach the goal of the CHRISGAS project: a 60% of synthesis gas (as x(H2)+ x(CO) on a N2 and dry basis) in the exit gas, which can be converted either into H2 or fuels. A Ni-MgAl2O4 commercial-like catalyst was tested downstream the gasification of clean wood made of saw dust, waste wood and miscanthus as herbaceous biomass. The effect of the temperature and contact time on the hydrocarbon conversion as well as the characterization of the used catalysts was studied. Low (<600 °C), medium (750°C–900 °C) and high temperature (900°C–1050 °C) tests were carried out in order to study, respectively, the tar cracking, the lowest operating reformer temperature for clean biomass, the methane conversion achievable as function of the temperature and the catalyst deactivation. The results demonstrate the possibility to produce an enriched syngas by the upgrading of the gasification stream of woody biomass with low sulphur content. However, for miscanthusthe development of catalysts with an enhanced resistance to sulphur poison will be the key point in the process development.
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| 2. |
- Brandin, Jan, 1958-, et al.
(författare)
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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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Rapport (övrigt vetenskapligt/konstnärligt)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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| 3. |
- Brandin, Jan, 1958-, et al.
(författare)
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Aerosolkatalysatorer för industriell gasrening
- 2016
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Rapport (refereegranskat)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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| 4. |
- Brandin, Jan, 1958-, et al.
(författare)
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Deactivation and Characterization of SCR Catalysts Used in Municipal Waste Incineration Applications
- 2018
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Ingår i: Catalysis Letters. - : Springer. - 1011-372X .- 1572-879X. ; 148:1, s. 312-327
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Tidskriftsartikel (refereegranskat)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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| 5. |
- Brandin, Jan, 1958-, et al.
(författare)
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Green LPG
- 2010
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The use of energy gases with renewable origins will become important with diminishing fossil resources. This as the infrastructure of the gaseous fuels is well built out and the distribution networks already exist. LPG is one of the most versatile fuels around, perfect for rural areas and in many other applications. The fossil origin of the fuel will, in today’s climate and environmental debate, however position it as a thing of the past and not part of the future energy supply. The technology and development performed under this and previous programs with the Swedish Gas Centre will however suggest a way to bridge this conception and make LPG a part of the future energy mix. A good starting point for two and three carbon energy gases is glycerine, with its three carbon backbone. The reason for focusing on glycerine is its benign chemical nature, it is:• Harmless from a toxic standpoint• Chemically inert• Non-corrosive• Relatively high energy density• Zero carbon dioxide emissions It is also readily available as the production of biofuels (from which glycerine is a sideproduct) in the world has increased markedly over the last 10 year period. This glut in the glycerol production has also lowered worldwide prices of glycerine.Since the key step in producing energy gases from glycerol is the dehydration of glycerol to acrolein, this step has attracted much attention during the development work. The step has been improved during the performed work and the need for any regeneration of the catalyst has been significantly reduced, if not omitted completely. This improvement allows for a simple fixed bed reactor design and will save cost in reactor construction as well as in operating costs of the plant. The same conclusion can be drawn from the combination of the two functionalities (dehydration and hydrogenation) in designing a catalyst that promote the direct reaction of 1-propanol to propane in one step instead of two. The experiments with the decarbonylation of acrolein to form ethane show that the catalyst deactivation rates are quite rapid. The addition of noble metal to the catalyst seems to improve the longevity of the catalyst, but the coking is still too severe to provide for a commercially viable process. It is believed that there is a possible way forward for the decarbonylation of acrolein to ethane; it will however require additional time and resources spent in this area. In this work it has been shown that all of the catalytic steps involved in the production of propane from glycerol have sufficient longterm stability and endurance and it is motivated to recommend that the project continues to pilot plant testing stage.
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| 6. |
- Brandin, Jan, 1958-, et al.
(författare)
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High-temperature and high concentration SCR of NO with NH3 : application in a CCS process for removal of carbon dioxide
- 2012
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Ingår i: Chemical Engineering Journal. - : Elsevier. - 1385-8947 .- 1873-3212. ; 191, s. 218-227
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Tidskriftsartikel (refereegranskat)abstract
- This study investigates several commercial selective catalytic reduction (SCR) catalysts (A–E) for application in a high-temperature (approximately 525 °C) and high-concentration (5000 ppm NO) system in combination with CO2 capture. The suggested process for removing high concentrations of NOx seems plausible and autothermal operation is possible for very high NO concentrations. A key property of the catalyst in this system is its thermal stability. This was tested and modelled with the general power law model using second-order decay of the BET surface area with time. Most of the materials did not have very high thermal stability. The zeolite-based materials could likely be used, but they too need improved stability. The SCR activity and the possible formation of the by-product N2O were determined by measurement in a fixed-bed reactor at 300–525 °C. All materials displayed sufficiently high activity for a designed 96% conversion in the twin-bed SCR reactor system proposed. The amount of catalyst needed varied considerably and was much higher for the zeolithic materials. The formation of N2O increased with temperature for almost all materials except the zeolithic ones. The selectivity to N2 production at 525 °C was 98.6% for the best material and 95.7% for the worst with 1000 ppm NOx in the inlet; at 5000 ppm NOx, the values were much better, i.e., 98.3 and 99.9%, respectively.
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| 7. |
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| 8. |
- Brandin, Jan, 1958-, et al.
(författare)
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Multi-function catalysts for glycerol upgrading
- 2010
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- During the last three years Biofuel-Solution, a privately held Swedish entity, has developed an IP-portfolio around gas-phase glycerol conversion into medium-value chemicals. The targeted chemicals have large to very large markets, to allow for use by more than a fraction of the glycerol available today without impacting the cost of the product. The reason behind is that glycerol is a by-product from the biofuel industry, including biodiesel and bioethanol. This indicates large production volumes, even though the glycerol is a fraction of the fuel produced. A by-product from any fuel process will be vast and therefore any chemical produced from this side-product will have to have a large market to offset it to. In order to avoid changing the fundamental market behavior, similar to what the biodiesel industry has done to the glycerol market. In the course of this work, several end-products have been targeted. These include plastic monomers, mono-alcohols and energy gases; using acrolein as a common starting point. To produce chemicals with high purity and efficiency, selective and active catalysts are required. For instance, a process for producing propionaldehyde and n-propanol has been developed to the point of demonstration and commercialization building on the gas-phase platform. By developing multi-function catalysts which perform more than one task simultaneously, synergies can be reached that cannot be achieved with traditional catalysts. For instance, by combining catalyst functionalities, reactions that are both endothermic and exothermic can be performed simultaneously. This mean lower inlet reactor temperatures (in this particular case) and a more even temperature distribution. By performing the dehydration of glycerol to acrolein in combination with another, exothermal reaction by-products can be suppressed and yields increased. It also means that new reaction pathways can be achieved, allowing for new ways to produce chemicals and fuels from glycerol. As in the case of ethane production from acrolein, where a catalyst surface has been devised where acrolein is first adsorbed. The actual mechanism is unknown but in speculation, the adsorbed acrolein is decarbonyled into ethylene and carbon monoxide on a first reaction site. The formed carbon monoxide diffuses to another active site, where it reacts with water through the so called water-gas shift reaction to carbon dioxide and hydrogen. Said carbon dioxide leaves as an end-product, and the hydrogen diffuses to another active site where it reacts with ethylene to form ethane. This gives a way of producing energy gases from glycerol in a very compact reactor set-up, effectively reducing footprint and capital cost and increasing productivity of an installation.
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| 9. |
- Brandin, Jan, 1958-, et al.
(författare)
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Poisoning of SCR Catalysts used in Municipal Waste Incineration Applications
- 2017
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Ingår i: Topics in catalysis. - : Springer. - 1022-5528 .- 1572-9028. ; 60:17-18, s. 1306-1316
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Tidskriftsartikel (refereegranskat)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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| 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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