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Gavrilovic, L., Brandin, J., Holmen, A., Venvik, H. J., Myrstad, R. & Blekkan, E. A. (2019). The effect of aerosol-deposited ash components on a cobalt-based Fischer–Tropsch catalyst. Reaction Kinetics, Mechanisms and Catalysis, 127(1), 231-240
Open this publication in new window or tab >>The effect of aerosol-deposited ash components on a cobalt-based Fischer–Tropsch catalyst
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2019 (English)In: Reaction Kinetics, Mechanisms and Catalysis, ISSN 1878-5190, E-ISSN 1878-5204, Vol. 127, no 1, p. 231-240Article in journal (Refereed) Published
Abstract [en]

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.

Place, publisher, year, edition, pages
Springer, 2019
Keywords
Fischer-Tropsch, cobalt, ash salts
National Category
Chemical Process Engineering
Research subject
Chemistry, Analytical Chemistry
Identifiers
urn:nbn:se:lnu:diva-82440 (URN)10.1007/s11144-019-01578-w (DOI)000468213500018 ()2-s2.0-85065020070 (Scopus ID)
Available from: 2019-05-06 Created: 2019-05-06 Last updated: 2019-08-29Bibliographically approved
Brandin, J. & Odenbrand, I. (2018). Deactivation and Characterization of SCR Catalysts Used in Municipal Waste Incineration Applications. Catalysis Letters, 148(1), 312-327
Open this publication in new window or tab >>Deactivation and Characterization of SCR Catalysts Used in Municipal Waste Incineration Applications
2018 (English)In: Catalysis Letters, ISSN 1011-372X, E-ISSN 1572-879X, Vol. 148, no 1, p. 312-327Article in journal (Refereed) Published
Abstract [en]

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.

Place, publisher, year, edition, pages
Springer, 2018
Keywords
Deactivation, Characterization, SCR catalysts, Municipal solid waste incineration
National Category
Chemical Engineering
Research subject
Technology (byts ev till Engineering), Bioenergy Technology
Identifiers
urn:nbn:se:lnu:diva-70202 (URN)10.1007/s10562-017-2229-8 (DOI)000419901300033 ()2-s2.0-85033454924 (Scopus ID)
Available from: 2018-01-29 Created: 2018-01-29 Last updated: 2019-08-29Bibliographically approved
Gavrilovic, L., Brandin, J., Holmen, A., Venvik, H., Myrstad, R. & Blekkan, E. (2018). Deactivation of Co-based Fischer-Tropsch catalyst by aerosol deposition of potassium salts. Industrial & Engineering Chemistry Research, 57(6), 1935-1942
Open this publication in new window or tab >>Deactivation of Co-based Fischer-Tropsch catalyst by aerosol deposition of potassium salts
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2018 (English)In: Industrial & Engineering Chemistry Research, ISSN 0888-5885, E-ISSN 1520-5045, Vol. 57, no 6, p. 1935-1942Article in journal (Refereed) Published
Abstract [en]

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.

Place, publisher, year, edition, pages
Washington, USA: American Chemical Society (ACS), 2018
Keywords
Fischer-Tropsch, Biomass, Cobalt catalyst, Deactivation, Potassium
National Category
Chemical Process Engineering
Research subject
Technology (byts ev till Engineering), Bioenergy Technology
Identifiers
urn:nbn:se:lnu:diva-70199 (URN)10.1021/acs.iecr.7b04498 (DOI)000425473900017 ()2-s2.0-85042101046 (Scopus ID)
Available from: 2018-01-29 Created: 2018-01-29 Last updated: 2019-08-29Bibliographically approved
Gavrilovic, L., Brandin, J., Holmen, A., Venvik, H., Myrstad, R. & Blekkan, E. (2018). Fischer-Tropsch synthesis: Investigation of the deactivation of a Co catalyst by exposure to aerosol particles of potassium salt. Applied Catalysis B: Environmental, 230, 203-209
Open this publication in new window or tab >>Fischer-Tropsch synthesis: Investigation of the deactivation of a Co catalyst by exposure to aerosol particles of potassium salt
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2018 (English)In: Applied Catalysis B: Environmental, ISSN 0926-3373, E-ISSN 1873-3883, Vol. 230, p. 203-209Article in journal (Refereed) Published
Abstract [en]

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.

Place, publisher, year, edition, pages
Elsevier, 2018
Keywords
Fischer-Trops, Co, K, Poison, Biomass
National Category
Chemical Process Engineering
Research subject
Technology (byts ev till Engineering), Bioenergy Technology
Identifiers
urn:nbn:se:lnu:diva-71817 (URN)10.1016/j.apcatb.2018.02.048 (DOI)000429500100021 ()2-s2.0-85042631094 (Scopus ID)
Available from: 2018-03-27 Created: 2018-03-27 Last updated: 2019-08-29Bibliographically approved
Brandin, J., Hulteberg, C. & Kusar, H. (2017). A review of thermo-chemical conversion of biomass into biofuels: focusing on gas cleaning and up-grading process steps. Stockholm: Kungliga Tekniska högskolan
Open this publication in new window or tab >>A review of thermo-chemical conversion of biomass into biofuels: focusing on gas cleaning and up-grading process steps
2017 (English)Report (Other (popular science, discussion, etc.))
Abstract [en]

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.

Abstract [sv]

Det är en stor utmaning att ersätta fossila bränslen inom transportsektorn, en tilltalande lösning är att använda biomassa och avfall för produktion av förnyelsebara drivmedel. Termokemisk omvandling av biomassa är ett lovande sätt för att producera olika sorters syntetiska drivmedel, då främst genom förgasningsteknik. En av de främsta utmaningarna i att använda termokemisk omvandling av biomassa och avfall är en rening och uppgradering av rågasen som produceras i förgasaren. Dessa material som är tänkta att ersätta olja och kol innehåller betydande mängder av alkaliska-, oorganiska-, svavel- och klor-föreningar.

De olika renings- och uppgraderingsstegen påverkar den totala verkningsgraden på hela processen, därför blir hanteringen av värme i de olika process strömmarna viktiga, som för alla processer i flera steg. Dessvärre, har de tillgängliga konventionella gas filtreringsenheterna för att ta bort partiklar och orenheter, och även efterföljande katalytiska omvandlingssteg, lägre optimala arbetstemperaturer än driftstemperaturen hos förgasningsenheterna.

Denna rapport fokuserar på pågående forskning och utveckling för att hitta ny teknik och lösningar när det gäller rening och uppgradering av rågas till syntesgas, samt efterföljande bränslesyntesprocesser, såsom hetgas-filtrering, smarta uppvärmnings lösningar och högre grad av integrationsprocess, samt katalysatorer som är mer tåliga mot deaktivering. Detta innebär att temperaturen bör vara så hög som möjligt för varje enskild renings- och en uppgraderingsenhet, likväl måste temperaturen och trycket hos den renade syntesgasen uppfylla kraven för nedströms bränslesyntes, d.v.s. Fischer-Tropsch-diesel eller metanol.

Ett antal orenheter behöver tas bort innan gasen som producerats i förgasaren kan användas, dessa inkluderar partiklar, tjäror, svavelföreningar och ammoniak. Partiklar bildas alltid vid förgasning, oberoende av vilken typ av förgasningsteknik som används, en första grovseparation utförs i en eller flera cyklonfilter vid höga temperaturer. För att separera de finare partiklarna används därefter olika keramiska- eller textilfilter, ett problem är dock kondensation av tjära i filtren, mycket arbete utförs på att försöka uppnå filtrering vid så hög temperatur som möjligt, så att man slipper tjärproblemen.

Det största hindret när det gäller rening och uppgradering av gaserna är tjära. För att bli av med tjäran från produktgasen finns ett antal olika alternativ, men det väsentligaste är att själva förgasaren drivs vid optimala förhållanden för att minimera att tjära bildas överhuvudtaget.

För förgasning med fluidiserad bädd och entrained flowförgasning skulle det första steget kunna vara katalytisk tjärkrackning efter att ha avlägsnat alla partiklar. Vid förgasning i fluidiserad bädd kan aktiva katalysatorer tillsättas till den fluidiserande bädden som kan kracka tjäran redan i bädden och hindra att ytterligare eventuell tjära bildas. Katalysatorer som används är främst naturliga mineraler, såsom dolomit och olivin, dessa användes normalt vid reformering eller krackning av kolväten.

Tjäran kan reformeras till vätgas och kolmonoxid genom termisk reformering såsom när temperaturen höjs till 1300ºC och tjäran sönderfaller. En annan metod för att avlägsna tjära från gasen är att tvätta gasen med hjälp av het olja (200-300ºC). Tjäran löser sig i den heta oljan, som delvis kan vara regenererad och den återstående tjärhaltiga delen kan antingen brännas eller återföras till förgasaren för förgasning.

Svavelföreningar är en annan viktig kontaminering som behöver tas bort ur gasen, svavelhalten i gasen beror främst på vilken typ av biomassa som används. Nivåer över 100 ppm inte är ovanligt och är inte acceptabelt för efterföljande nedströms katalytiska processer, eller om utsläppen av t.ex. SO2 ska hållas nere.

Svavel kan separeras genom adsorption med ZnO som är en irreversibel process, eller genom kommersiellt tillgängliga reversibla adsorbenter som kan användas. Ytterligare alternativ är att tvätta/skrubba gasen med en aminlösning. Om ett reversibelt alternativ används kan elementärt svavel framställas med hjälp av Claus-processen.

Ammoniak bildas vid förgasning och nivåer runt 3000 ppm är inte ovanligt, men anses vanligtvis inte ett problem efterföljande nedströms processer. Om gasen förbränns, kan dock kväve eller i värsta fall NOx (så kallad bränsle NOx) bildas. Det finns dock indikationer på att problem kan uppstå, speciellt när förgasning följs av nedströms katalytiska processer, exempelvis vid ångreformering där katalysatorn kan deaktiveras vid långvarig exponering för ammoniak

Sammansättningen på produktgasen beror framförallt på valet av förgasningsteknik, vilket förgasningsmedel som används, samt viken sorts biomassa sam används. Valet av förgasningsmedel, dvs. luft, syre, vatten, är extra viktigt eftersom det har en direkt inverkan på sammansättningen och kvaliteten hos gasen. Valet av förgasningsmedel påverkar också vilka renings- och uppgraderingsprocesser som kan användas och lämpar sig bäst för olika slutanvändningstillämpningar som t.ex. drivmedel eller för gröna kemikalier.

Idealt består en syntesgas som är uppgraderad av vätgas och kolmonoxid i korrekt förhållande, med mycket låga halter vatten och koldioxid. Detta innebär att tjäror, partiklar, alkalisalter och oorganiska föreningar, som nämnts tidigare, måste avlägsnas för de flesta tillämpningarna. Genom att använda syre som förgasningsmedel, i stället för luft, kan innehållet av kväve i gasen minimeras, så man undviker efterföljande dyrbar separation av kväve.

Sammanfattningsvis finns det ett antal olika användningsområden för olika producerade syntesgaser. De olika tillämpningarna kommer att diskuteras i rapporten med början med produktion av vätgas, följt av framställning av syntetisk naturgas (SNG), metanol, dimetyleter, Fischer-Tropsch-diesel och syntes av högre alkoholer, samt beskrivningar av metoder som kombinerar dessa. Processystemen är olika där syntes av SNG och metanol begränsas jämvikt, medan syntes av dimetyleter, (DME), FT-diesel och alkoholer inte är jämviktsberoende. Samtliga reaktioner är exoterma, med undantag för ångreformering av metan och tjäror, vilket medför att det är viktigt att kontrollera temperaturökningen i reaktorerna. Dessutom måste syntes av metanol utföras vid högt tryck (50-100 bar) för att vara industriellt gångbar.

För att hålla nere kapitalkostnaderna för hela reningssystemet och systemets effektivitet behöver man kompromissa, eftersom hanteringen av fast avfall, t.ex. aska, absorberande medel, bäddmaterial och avloppsvatten alla innebär kostnader.

Att installera väldigt effektiva katalysatorer resulterar i dyrare gasrening på grund av onödiga kostnader, men nedströms syntesprocesser kommer att dra nytta av effektiv gasrening som förlänger katalysatorernas livstid, särskilt för Fischer-Tropsch-diesel, och DME/metanol syntes. Generellt måste katalysatorerna i de olika uppgraderingsprocesserna vara mer stabila och motståndskraftiga mot olika typer av deaktivering.

Slutligen är process-intensifiering ett viktigt område för utveckling inom hela kemiindustrin som bland annat omfattar integration av både syntes och separationssteg, med olika former av avancerad värmeväxling med värmeintegration för att öka värmeöverföringshastigheten, och att kombinera exoterma och endoterma reaktioner. Därför är det nödvändigt med nya innovativa lösningar för rening och uppgradering av gaserna för att få fram kostnadseffektiva och effektiva tillämpningar.

Place, publisher, year, edition, pages
Stockholm: Kungliga Tekniska högskolan, 2017. p. 55
Series
TRITA-CHE-Report, ISSN 1654-1081 ; 2017:24
Keywords
gas cleaning, up-grading, thermo-chemical, biomass, gasification, biofuel
National Category
Energy Systems
Research subject
Technology (byts ev till Engineering), Bioenergy Technology
Identifiers
urn:nbn:se:lnu:diva-63084 (URN)978-91-7729-366-8 (ISBN)
Funder
Swedish Energy Agency
Available from: 2017-05-08 Created: 2017-05-08 Last updated: 2017-09-14Bibliographically approved
Parsland, C., Brandin, J., Benito, P., Hoang Ho, P. & Fornasari, G. (2017). Ni-substituted Ba-hexaaluminate as a new catalytic material in steam reforming of tars. In: Europacat: 13th European Conference on Catalysis, 27-31 August 2017, Florence Italy: . Paper presented at Europacat 2017, 13th European Conference on Catalysis.
Open this publication in new window or tab >>Ni-substituted Ba-hexaaluminate as a new catalytic material in steam reforming of tars
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2017 (English)In: Europacat: 13th European Conference on Catalysis, 27-31 August 2017, Florence Italy, 2017Conference paper, Poster (with or without abstract) (Refereed)
Keywords
catalysis
National Category
Materials Chemistry
Research subject
Natural Science, Chemistry; Technology (byts ev till Engineering), Forestry and Wood Technology
Identifiers
urn:nbn:se:lnu:diva-78701 (URN)
Conference
Europacat 2017, 13th European Conference on Catalysis
Available from: 2018-11-06 Created: 2018-11-06 Last updated: 2018-12-10Bibliographically approved
Brandin, J. & Odenbrand, I. (2017). Poisoning of SCR Catalysts used in Municipal Waste Incineration Applications. Paper presented at 17th Nordic Symposium on Catalysis, 2016, Lund Sweden. Topics in catalysis, 60(17-18), 1306-1316
Open this publication in new window or tab >>Poisoning of SCR Catalysts used in Municipal Waste Incineration Applications
2017 (English)In: Topics in catalysis, ISSN 1022-5528, E-ISSN 1572-9028, Vol. 60, no 17-18, p. 1306-1316Article in journal (Refereed) Published
Abstract [en]

A commercial vanadia, tungsta on titania SCRcatalyst was poisoned in a side stream in a waste incinerationplant. The effect of especially alkali metal poisoningwas observed resulting in a decreased activity at long timesof exposure. The deactivation after 2311 h was 36% whilethe decrease in surface area was only 7.6%. Thus the majorcause for deactivation was a chemical blocking of acidicsites by alkali metals. The activation–deactivation modelshowed excellent agreement with experimental data. Themodel suggests that the original adsorption sites, fromthe preparation of the catalyst, are rapidly deactivated butare replaced by a new population of adsorption sites dueto activation of the catalyst surface by sulphur compounds(SO2, SO3)in the flue gas.

Place, publisher, year, edition, pages
Springer, 2017
Keywords
Poisoning, Waste incineration, SCR catalyst, Modelling of activation and deactivation
National Category
Chemical Process Engineering Energy Systems Inorganic Chemistry Bioenergy Renewable Bioenergy Research
Research subject
Technology (byts ev till Engineering), Bioenergy Technology
Identifiers
urn:nbn:se:lnu:diva-66849 (URN)10.1007/s11244-017-0816-y (DOI)000413848700005 ()2-s2.0-85021815107 (Scopus ID)
Conference
17th Nordic Symposium on Catalysis, 2016, Lund Sweden
Available from: 2017-07-07 Created: 2017-07-07 Last updated: 2019-08-29Bibliographically approved
Hulteberg, C., Leveau, A. & Brandin, J. (2017). Pore Condensation in Glycerol Dehydration: Modification of a Mixed Oxide Catalyst. Paper presented at 17th Nordic Symposium of Catalysis, JUN 14-16, 2016, Lund.. Topics in catalysis, 60(17-18), 1462-1472
Open this publication in new window or tab >>Pore Condensation in Glycerol Dehydration: Modification of a Mixed Oxide Catalyst
2017 (English)In: Topics in catalysis, ISSN 1022-5528, E-ISSN 1572-9028, Vol. 60, no 17-18, p. 1462-1472Article in journal (Refereed) Published
Abstract [en]

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.

Place, publisher, year, edition, pages
Springer, 2017
Keywords
Glycerol, Pore Condensation, Dehydration, Acrolein, Deactivation
National Category
Chemical Process Engineering
Research subject
Technology (byts ev till Engineering), Bioenergy Technology
Identifiers
urn:nbn:se:lnu:diva-65539 (URN)10.1007/s11244-017-0827-8 (DOI)000413848700019 ()2-s2.0-85019753837 (Scopus ID)
Conference
17th Nordic Symposium of Catalysis, JUN 14-16, 2016, Lund.
Available from: 2017-06-19 Created: 2017-06-19 Last updated: 2019-08-29Bibliographically approved
Hulteberg, C., Odenbrand, I., Gustafson, J., Brandin, J. & Lundgren, E. (2017). Preface: Special issue of Topics in Catalysis constitutes the Proceedings of the 17th Nordic Symposium of Catalysis. Topics in catalysis, 60(17-18), 1275-1275
Open this publication in new window or tab >>Preface: Special issue of Topics in Catalysis constitutes the Proceedings of the 17th Nordic Symposium of Catalysis
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2017 (English)In: Topics in catalysis, ISSN 1022-5528, E-ISSN 1572-9028, Vol. 60, no 17-18, p. 1275-1275Article in journal, Editorial material (Other academic) Published
Place, publisher, year, edition, pages
Springer, 2017
National Category
Chemical Process Engineering
Research subject
Technology (byts ev till Engineering), Bioenergy Technology
Identifiers
urn:nbn:se:lnu:diva-68901 (URN)10.1007/s11244-017-0814-0 (DOI)000413848700001 ()2-s2.0-85020121108 (Scopus ID)
Available from: 2017-11-22 Created: 2017-11-22 Last updated: 2019-08-29Bibliographically approved
Brandin, J., Strand, M. & Ali, S. (2016). Aerosolkatalysatorer för industriell gasrening. Energiforsk
Open this publication in new window or tab >>Aerosolkatalysatorer för industriell gasrening
2016 (English)Report (Refereed)
Abstract [en]

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.

Abstract [sv]

I detta arbete har aerosolkatalysatorer, det vill säga små partiklar (med aerodynamisk diameter upp till 100 µm) av katalytiskt aktiva material, suspenderade i gas, undersökts med tänkt användning för NOx-reduktion med ammoniak (SCR) i mindre industriella anläggningar och pannor som ett alternativ till SNCR. Aerosolpartiklarna är avsedda att injiceras i rökgasen vid hög temperatur, tillsammans med ammoniak/urea, och avskiljs på ett partikelfilter, av slangfiltertyp, vid låg temperatur. Reduktion av NOx kan då ske dels vid den pneumatiska transporten av katalysatorn genom pannan och dels i den katalytiskt aktiva filterkaka som byggs upp på slangfiltret. Katalysatorerna måste ha tillräckligt hög aktivitet, vid den pneumatiska transporten, för att begränsa förbrukningen, vara tillräckligt billiga för att kunna användas som förbrukningsvara och vara ofarliga för människor och miljö. Två material togs fram under arbetet som tänkbara kandidater; naturliga zeoliter och en FeSO4/träkolkatalysator. Kostnadsuppskattningar för en tänkt 1 MWth-anläggning, visar att det behövs närmre 50 % reduktionsgrad för att ekonomiskt motivera införande av SNCR för små anläggningar (<25 GWh, NOx-reduktion mellan 30-50 % och 2 i stökiometri), detta både för användning av urea och flytande vattenfri ammoniak med dagens NOx-avgift. Resultatet är måttligt, som bäst nås 15-20 % kostnadsreduktion jämfört med utan åtgärd. Höjs avgiften till 60 SEK/kg NOx, förbättras situationen, men resultaten är fortfarande måttliga (20-25 % kostnadsreduktion). Vid användande av aerosolkatalysatorer, och en reduktionsgrad av 85 %, fås bra utfall vid låga katalysatorkostnader (0.5-2 SEK/kg), men anläggningen klarar på sin höjd en kostnad på 4 SEK/kg. Uppskattade priser för aerosolkatalysatorn är i storleksordningen 10 SEK/kg. För att processen ska bli ekonomiskt intressant, måste katalysatorn kunna recirkuleras för att ge en sänkt kostnad för katalysatorförbrukning.

Place, publisher, year, edition, pages
Energiforsk, 2016. p. 87
National Category
Materials Chemistry
Identifiers
urn:nbn:se:lnu:diva-41773 (URN)9789176733158 (ISBN)
Funder
ÅForsk (Ångpanneföreningen's Foundation for Research and Development), 36366-1
Available from: 2015-04-07 Created: 2015-04-07 Last updated: 2017-06-01Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-4162-3680

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