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  • 1.
    Andrae, Johan
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk reaktionsteknik.
    Johansson, David
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk reaktionsteknik.
    Björnbom, Pehr
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk reaktionsteknik.
    Risberg, Per
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.), Förbränningsmotorteknik.
    Kalghatgi, Gautam
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.), Förbränningsmotorteknik.
    Cooxidation in the auto-ignition of primary reference fuels and n-heptane/toluene blends2005Inngår i: Combustion and Flame, ISSN 0010-2180, E-ISSN 1556-2921, Vol. 140, nr 4, s. 267-286Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Auto-ignition of fuel mixtures was investigated both theoretically and experimentally to gain further understanding of the fuel chemistry. A homogeneous charge compression ignition (HCCI) engine was run under different operating conditions with fuels of different RON and MON and different chemistries. Fuels considered were primary reference fuels and toluene/n-heptane blends. The experiments were modeled with a single-zone adiabatic model together with detailed chemical kinetic models. In the model validation, co-oxidation reactions between the individual fuel components were found to be important in order to predict HCCI experiments, shock-tube ignition delay time data, and ignition delay times in rapid compression machines. The kinetic models with added co-oxidation reactions further predicted that an n-heptane/toluene fuel with the same RON as the corresponding primary reference fuel had higher resistance to auto-ignition in HCCI combustion for lower intake temperatures and higher intake pressures. However, for higher intake temperatures and lower intake pressures the n-heptane/toluene fuel and the PRF fuel had similar combustion phasing.

  • 2. Budinova, T.
    et al.
    Ekinci, E.
    Yardim, F.
    Grimm, Alejandro
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk reaktionsteknik.
    Björnbom, Emilia
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk reaktionsteknik.
    Minkova, V.
    Goranova, M.
    Characterization and application of activated carbon produced by H3PO4 and water vapor activation2006Inngår i: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 87, nr 10, s. 899-905Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Activated carbons have been prepared from woody biomass birch by using various activation procedures: a) treatment with phosphoric acid and pyrolysis at 600 degrees C in inert atmosphere, b) the same as in (a) followed by steam activation at the same temperature and c) treatment with phosphoric acid and direct pyrolysis in a stream of water vapor at 700 degrees C. The surface area and the porosity of the activated carbons were strongly dependent on the treatment after impregnation with H3PO4 (pyrolysis in inert atmosphere, steam pyrolysis or combination of both). Activated carbon, prepared by impregnation with phosphoric acid followed by steam pyrolysis (steam activation) had highly developed porous structure and the largest surface area among all prepared carbons (iodine number 1280 mg/g and BET surface area 1360 m(2)/g). The adsorption capacity of this sample for Hg(II) from aqueous solution was studied in varying treatment conditions: contact time, metal ion concentration and pH. The adsorption followed Langmuir isotherms and the adsorption capacity for Hg(II) at 293 K was 160 mg/g.

  • 3. Feng, B.
    et al.
    Wang, C. Y.
    Zhu, Bin
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk reaktionsteknik.
    Catalysts and performances for direct methanol low-temperature (300 to 600 degrees C) solid oxide fuel cells2006Inngår i: Electrochemical and solid-state letters, ISSN 1099-0062, E-ISSN 1944-8775, Vol. 9, nr 2, s. A80-A81Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A novel anode catalyst, C-MO-SDC (C=activated carbon/carbon black, M=Cu, Ni, Co, SDC=Ce0.9Sm0.1O1.95) was synthesized by employing a citrate/nitrate combustion technique. Carbon materials, e.g., activated carbon and carbon black were first used to improve the solid oxide fuel cell (SOFC) anode properties, especially to improve the microstructure and to enhance the anode conductivity and catalyst function for directly operating methanol as the fuel. The resulting anode catalyst C-MO-SDC materials used in a SOFC device have successfully achieved a high power density of 0.25 W cm(-2) by directly operating the methanol at 560 degrees C.

  • 4. Feng, B.
    et al.
    Wang, C. -Y
    Zhu, Bin
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk reaktionsteknik.
    Novel AC-M-SCC anode materials for solid oxide fuel cells using methanol at intermediate or low temperature2005Inngår i: Proceedings of the 3rd International Conference on Fuel Cell Science, Engineering, and Technology, ASME Press, 2005, s. 785-788Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In this paper, novel anode materials for solid oxide fuel cells which can directly operate liquid fuels at intermediate or low temperature were investigated. These materials were based on the activated carbons supported transition metal catalysts (AC-M) and the solid carbonate-ceria composite (SCC) materials, which were prepared via the sol-gel route. The SCCs possess both oxide-ion and proton conductivity, being used as multi-ion conductors. Activated carbons supported transition metals were used to improve the characters of anode materials and especially to enhance the anode catalyst function to liquid fuels, e.g., methanol. The internal reforming of liquid fuels was proved. There is no external reforming system needed. We used also the chemical methods to improve the commercial activated carbons. The microstructure, conductivity and electrochemical properties of anode materials were investigated as functions of the activated carbon pre-treating condition. Using these novel materials, the power intensity of 0.2 W/cm 2 was achieved for fuel cells directly operating the methanol at 600°C.

  • 5.
    Garcia-Rojas, L. M.
    et al.
    Universidad de Pinar del Río, Cuba.
    Marquez-Montesino, Francisco
    Universidad de Pinar del Río, Cuba.
    Aguiar-Trujillo, Leonardo
    Universidad de Pinar del Río, Cuba.
    Arauso-Perez, Jesus
    Universidad de Zaragoza, Spain.
    Carballo-Abreu, Leila R.
    Universidad de Pinar del Río, Cuba.
    Orea Igarza, U.
    Zanzi, Rolando
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk reaktionsteknik. KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk teknologi.
    Rendimiento de los productos de la descomposición térmica De la madera de eucalyptus saligna smith a diferentes alturas del fuste comercial2009Inngår i: Revista Chapingo, Serie Ciencias Forestales y del Ambiente, ISSN 0186-3231, Vol. 15, nr 2, s. 147-154Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this work the qualitative and quantitative results of the thermal pyrolysis of Eucalyptus Saligna Smith is presented, to different heights of the commercial wooden log. The wood was collected from Pinar del Rio, Cuba. The need to use this wood like energy source in the region led to the research at laboratory scale. The used trees were 20 and 22 years old, from which 20 cm disks were cut at 25; 55 and 85 % height of the log, milled to chips and air dried. The chemical composition was determined and was carried out the previous analysis of the samples, as well as the thermal decomposition in micro scale. The study of products from the pyrolysis (coal and tar), it was made in a reactor of fixed channel. The caloric value of the biomass and its charcoal was determined. The influence of the height of the log in the product yields from the pyrolysis was studied.

    As significant differences was observed as for the chemical composition of the studied wood: cellulose, hemicelulose and lignine, being observed an apparent increase of the lignine percentage with the height of the tree. The previous analysis belongs together with the chemical composition of the studied biomass. A small decrease was observed in the yield of the coal and of the percentage of tars with the height of the tree, this belongs together with the variation of the chemical composition according to the height of the tree. The biggest yield of coal and caloric value was achieved at the lowest height of the tree. The contribution to gas goes increasing with the height.

  • 6.
    Grimm, Alejandro
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk reaktionsteknik.
    Górdon, M.
    Zanzi, Rolando
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk reaktionsteknik. KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk teknologi.
    Björnbom, Emilia
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk reaktionsteknik.
    Catalytic oxidation of combustibles representative of flue gases from wood combustion2005Konferansepaper (Fagfellevurdert)
  • 7.
    Grimm, Alejandro
    et al.
    KTH, Tidigare Institutioner (före 2005), Kemiteknik. KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk reaktionsteknik.
    Pérez Gordón, Maria
    Zanzi, Rolando
    KTH, Tidigare Institutioner (före 2005), Kemiteknik. KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk teknologi.
    Björnbom, Emilia
    KTH, Tidigare Institutioner (före 2005), Kemiteknik. KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk reaktionsteknik.
    Laboratory tests of catalysts for total oxidation of combustibles representative for flue gases from combustion of wood2004Konferansepaper (Fagfellevurdert)
  • 8.
    Grimm, Alejandro
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk reaktionsteknik.
    Zanzi, Rolando
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk reaktionsteknik.
    Björnbom, Emilia
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk reaktionsteknik.
    Cukierman, A. L.
    Tecnología Especial, Depto Tecnología Farmacéutica, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires.
    Comparison of different types of biomasses for copper biosorption2007Inngår i: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 99, nr 7, s. 25559-2565Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Three biomass, birch wood Betula sp., marine brown alga Fucus vesiculosus, and terrestrial moss Pleurozium schreberi, have been compared as raw materials for preparation of biosorbents for removal of copper ions from diluted water solutions. Small sample doses (0.5 g/100 ml) of the biosorbents prepared from alga and moss enabled more than 90% removal of Cu(II) ions from diluted water solutions (5-20 mg/l). The sample from sawdust was less effective.A pseudo-second-order rate model properly described the experimental kinetic data for the biosorbents. The maximum sorption capacities (X,) determined from the experimental equilibrium isotherms by applying the Langmuir model showed that the alga had the best copper-binding ability (X-m = 23.4 mg/g), followed by the moss (X-m = 11.1 mg/g), and the sawdust (X-m = 4.9 mg/g). No visible damages or performance losses were detected for the alga and moss after five sorption-desorption cycles using diluted HCl as eluent.

  • 9.
    Kiros, Yohannes
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk teknologi.
    Bursell, Martin
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk reaktionsteknik.
    Low energy consumption in chlor-alkali cells using oxygen reduction electrodes2008Inngår i: International Journal of Electrochemical Science, E-ISSN 1452-3981, Vol. 3, nr 4, s. 444-451Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    An air/oxygen gas diffusion electrode for use as a cathode to replace the traditional hydrogen-evolving electrode in chlor-alkali electrolysis was assessed. Attempts to stabilize the cathode have been addressed in order to circumscribe problems associated with "flooding" or "wetting-in" properties. Variation of the hydrophobic concentration in the gas diffusion layer had a significant effect on the electrochemical tests of both the half-cell and electrolysis of the chlor-alkali cells. Life-tests as well as performance characteristics for both types of cells have shown encouraging results at NaOH concentration levels of ca 8M NaOH and temperatures of 70 and ca. 80 degrees C, respectively. Though cell voltages of about 2V were achieved and thereby reducing the energy consumption by 30-35% compared to the state-of-the-art membrane cell, the contributions of overvoltages were still high compared to the equilibrium potential of about 1.23V. Efforts to limit the individual parts of overvoltages as well as maintenance of the zero-gap cell at least on the anode side have been carried out. Two different kinds of cation exchange membranes have been used for the electrolysis cell. However, the cation exchange membrane with hydrophilic properties having high initial performances showed tendencies of blister formations.

  • 10.
    Kiros, Yohannes
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk teknologi.
    Pirjamali, M.
    Bursell, Martin
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk reaktionsteknik.
    Oxygen reduction electrodes for electrolysis in chlor-alkali cells2006Inngår i: Electrochimica Acta, ISSN 0013-4686, E-ISSN 1873-3859, Vol. 51, nr 16, s. 3346-3350Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Oxygen reduction electrodes, containing non-noble metal catalysts supported on high surface area carbon and wet-proofed with PTFE were tested under reaction conditions for the chlor-alkali electrolysis. Double-layer gas diffusion electrodes were prepared by rolling of an active layer and diffusion layer on a nickel wire screen, compressed and sintered at 300 degrees C. Electrochemical measurements for substantiating the activity and stability of the half-cells were conducted in 8 M NaOH by supplying oxygen at a cell temperature of 70 degrees C and a constant current load of 300 mA cm(-2). An electrolysis cell with a dimensionally stable anode (DSA) and double-layered cathode was assembled, where 4.8 M NaCl and oxygen were supplied, respectively, for the production of chlorine and NaOH. The cell performances as well as stability of the electrodes were investigated at about 80 degrees C. This study shows that by replacing the high voltage consuming hydrogen-evolving reaction and by adopting highly active electrocatalysts as cathode materials, energy savings of more than 30% could be realized.

  • 11.
    Kiros, Yohannes
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk reaktionsteknik.
    Pirjamali, Massoud
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk reaktionsteknik.
    Preparation of high surface area La0.1Ca0.9MnO3 and its electrochemical activities2007Inngår i: THERMEC 2006, Pts 1-5 / [ed] Chandra, T; Tsuzaki, K; Militzer, M; Ravindran, C, 2007, Vol. 539-543, s. 1361-1366Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The use of perovskites as potential heterogeneous catalysts in a number of chemical and electrochemical reactions have attracted the research interest due to high surface reactivity and low cost. Since catalysis is strongly dependent on surface areas, texture and structural homogeneity, the development of effective modes of preparation of perovskites is of utmost importance for the achievement of high performances, especially for electrochemical applications in fuel cells and metal/air batteries. The precipitation reaction method for the synthesis of La0.1Ca0.9MnO3 at low temperatures in the presence of alkaline support electrolyte has shown significant gain in the surface and electrochemical properties. Enhanced BET-surface area of this production method as compared to the dry pyrolysis method was obtained. Multifunctional application for cathodic reactions in alkaline fuel cell (AFC) and intermediate temperature solid oxide fuel cell (IT-SOFC) as well as for bifunctional systems of both oxygen reduction reaction (orr) and oxygen evolution reaction (oer) has been investigated. Parameter optimisations of the ingoing materials and analyses of the solid-state properties of the catalyst pertaining to structural, chemical and surface characteristics have also been carried out.

  • 12.
    Malmberg, Helena
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk reaktionsteknik.
    Ruiz, Vanesa
    Instituto Nacional del Carbón (CSIC), Oviedo.
    Blanco, Clara
    Instituto Nacional del Carbón (CSIC), Oviedo.
    Santamaria, Ricardo
    Instituto Nacional del Carbón (CSIC), Oviedo.
    Lundblad, Anders
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk reaktionsteknik.
    Björnbom, Pehr
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk reaktionsteknik.
    An insight into Faradaic phenomena in activated carbon investigated by means of the microelectrode technique2007Inngår i: Electrochemistry communications, ISSN 1388-2481, E-ISSN 1873-1902, Vol. 9, nr 9, s. 2320-2324Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Cyclic voltammetry was performed on activated carbon particles in a microelectrode setup to investigate the behaviour of an activated carbon with oxygen functionalities. Quinoid type redox peaks were clearly seen in the potential region around -0.5 V vs. Hg/HgO. After polarization below -0.4 V, an anodic peak confirms previous studies using a pristine carbon, but in the present work much higher in intensity. In addition, a corresponding cathodic peak, not previously reported, was also found. The appearance of this pair of peaks in a functionalized carbon may be connected to reversible hydrogen adsorption together with Faradaic reactions involving oxygenated functional groups.

  • 13.
    Malmberg, Helena
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk reaktionsteknik.
    Zuleta, Marcelo
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk reaktionsteknik.
    Lundblad, Anders
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk reaktionsteknik.
    Björnbom, Pehr
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk reaktionsteknik.
    Ionic transport in pores in activated carbons for EDLCs2006Inngår i: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 153, nr 10, s. A1914-A1921Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The transport properties and morphology of an activated carbon containing macro-, meso-, and micropores were studied and compared to a sophisticated fully nanoporous carbon that almost lacks meso- and macropores. The morphology of the activated carbon was studied using nitrogen adsorption methods and the pore size distribution was investigated using Barret, Joyner, and Halenda and density functional theory models. The transport properties were studied using a microelectrode technique that allows for determination of the effective diffusivity, D-eff. For the meso/macroporous carbon the effective diffusivity was determined using potential step experiments and analysis for both Cottrell and filling diffusivities were made. The Cottrell diffusivity was smaller than the value of the filling diffusivity, with mean values of (9.4 +/- 3.8) x 10(-14) m(2) s(-1) and (3.1 +/- 1.6) x 10(-12) m(2) s(-1), respectively. This difference in diffusivities is the basis for an agglomerate hypothesis presented for the meso/macroporous carbon. The results for the meso/macroporous carbon are compared with the corresponding results for the sophisticated fully nanoporous carbon. This gave further evidence for the presented agglomerate hypothesis.

  • 14. Marquez-Montesino, Francisco
    et al.
    Correa-Mendez, Fermin
    Glauco-Sanchez, Caio
    Zanzi-Vigouroux, Rolando
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk reaktionsteknik.
    Guadalupe Rutiaga-Quinones, Jose
    Aguiar-Trujillo, Leonardo
    Pyrolytic Degradation Studies of Acacia mangium wood2015Inngår i: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 10, nr 1, s. 1825-1844Artikkel, forskningsoversikt (Fagfellevurdert)
    Abstract [en]

    Pyrolytic degradation of Acacia mangium wood was studied. The chemical composition of biomass, immediate and elemental analyses and calorific value for biomass and char, were determined. The standard and the derivative curve thermogravimetric analysis (TGA and DTG) were obtained. Devolatilization maximum of values between 250 +/- 20 degrees C and 380 +/- 20 degrees C were observed, with completion after 2 h, which confirms the selection of 2 hours for pyrolysis. Kinetic study was performed at different heating rates for a conversion rate from 20% to 80%. Average values of activation energy for temperature in degrees K of 228.57 kJ/mol for Biomass 1 and 199.36 kJ/mol for Biomass 2 were obtained by the isoconversion method of FWO. The lower value of activation energy for Biomass 2 was related to the possible catalytic activity of ash. The values of correlation coefficient from 0.9418 to 0.9946 for Biomass 1 and from 0.8706 to 0.9918 for Biomass 2, indicate the reliability of the first-order reaction model. The caloric values obtained were: Biomass 1 (16962 kJ/kg), Biomass 2 (16974 kJ/kg), chars from Biomass 1 (between 23731 y 26 942 kJ/kg) and gas from Biomass 1 and Biomass 2 (3858.7 and 4859.4 kJ/m(3), respectively).

  • 15.
    Minkova, V.
    et al.
    Institute of Organic Chemistry, Bulgarian Academy of Sciences, Sofia .
    Marinov, S. P.
    Institute of Organic Chemistry, Bulgarian Academy of Sciences, Sofia .
    Zanzi, Rolando
    KTH, Tidigare Institutioner (före 2005), Kemiteknik. KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk teknologi.
    Bjornbom, E.
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk reaktionsteknik.
    Budinova, T.
    Institute of Organic Chemistry, Bulgarian Academy of Sciences, Sofia .
    Stefanova, M.
    Institute of Organic Chemistry, Bulgarian Academy of Sciences, Sofia .
    Lakov, L.
    Institute of Organic Chemistry, Bulgarian Academy of Sciences, Sofia .
    Thermochemical treatment of biomass in a flow of steam or in a mixture of steam and carbon dioxide2000Inngår i: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 62, nr 1, s. 45-52Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Simultaneous pyrolysis and gasification of biomass samples of different origin is performed in a flow of steam or in a mixture of steam and carbon dioxide. Wastes from birch wood, olive stones, bagasse, and pellets from straw and Miscanthus are used as feedstock. The raw materials are heated with 10 degrees C/min to 750 degrees C at atmospheric pressure and kept for a period of 2 h at this temperature, Laboratory experimental equipment with a horizontal rotating stainless steel reactor is used. The oxygen-containing functional groups in the solid products (-COOH, =CO and -OH) are determined using the method of Boehm. The results are compared with those obtained in treatment in inert atmosphere as well as with those obtained in a stationary reactor. The rotating pyrolysis reactor seems suitable for production of energy-rich gaseous products and activated carbons.

  • 16.
    Minkova, V.
    et al.
    Institute of Organic Chemistry, Bulgarian Academy of Sciences, Sofia .
    Razvigorova, M.
    Institute of Organic Chemistry, Bulgarian Academy of Sciences, Sofia .
    Bjornbom, E.
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk reaktionsteknik.
    Zanzi, Rolando
    KTH, Tidigare Institutioner (före 2005), Kemiteknik. KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk teknologi.
    Budinova, T.
    Institute of Organic Chemistry, Bulgarian Academy of Sciences, Sofia .
    Petrov, N.
    Institute of Organic Chemistry, Bulgarian Academy of Sciences, Sofia .
    Effect of water vapour and biomass nature on the yield and quality of the pyrolysis products from biomass2001Inngår i: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 70, nr 1, s. 53-61Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Slow pyrolysis/activation of biomass in a flow of steam is studied in laboratory equipment supplied with a fixed bed reactor. Forestry and agricultural residues of different origin are selected as raw materials (birch wood, olive stones, bagasse, pelletised straw and miscanthus). The final pyrolysis temperature is varied in the range 700-800 degreesC and the duration of the activation is 1 or 2 h. The effect of both the nature of the investigated biomass samples and the presence of water vapour on the quality of the pyrolysis products is in the focus of interest of this work. Column chromatography is used to characterize the liquid products. The surface area and the acid-base neutralization capacity of the solid products are determined by the adsorption capacity towards iodine and reactions with EtONa and HCl. The results are compared with those obtained in pyrolysis in inert atmosphere of nitrogen. It is shown that the presence of steam has strong effect on the yield and properties of the products. Significant part of the liquid product is found dissolved in the water phase obtained after condensation of the volatiles. The solid products obtained in the presence of steam have the properties of activated carbons.

  • 17.
    Rifau, Ali
    et al.
    University Sains Malaysia.
    Zainal, Zainal
    University Sains Malaysia.
    Mutharasu, D.
    Fauzi, A.
    Kiros, Yohannes
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk teknologi.
    Zhu, Bin
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk reaktionsteknik.
    Zanzi Vigouroux, Rolando
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk teknologi.
    Performance study on an Intermediate Temperature Solid Oxide Fuel Cell (IT-SOFC) fabricated by dry pressing method2006Inngår i: American Journal of Applied Sciences, ISSN 1546-9239, E-ISSN 1554-3641, Vol. 3, nr 9, s. 2020-2024Artikkel i tidsskrift (Fagfellevurdert)
  • 18. Rong-Li, J.
    et al.
    Cheng-Yang, W.
    Zhu, Bin
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk reaktionsteknik.
    Preparation of platinum supported on carbon blacks with different surface chemical characteristics2005Inngår i: Proceedings of the 3rd International Conference on Fuel Cell Science, Engineering, and Technology, ASME Press, 2005, s. 235-238Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In a study of the preparation of Pt/C eletrocatalysts, a set of modified Vulcan XC-72R carbon black supports have been prepared by nitric acid or hydrogen peroxide oxidation, or thermal treatment in nitrogen flow. The supports obtained by these methods had largely identical pore structure, but different from the amount of surface oxygen-containing groups. The physical and surface chemical nature of the supports was characterized by XPS, BET, FTIR and acid-base titration. The above pre-treatment-carbon supported platinum catalysts were prepared by impregnation-reduction method with formaldehyde as the reducing agent, H2PtCl6 as precursor. The effect of the amount of surface oxygen-containing groups of Vulcan XC-72R carbon black on Pt/C catalysts dispersion was studied by the characterization with XRD and TEM. It has been found that decreasing the amount of surface oxygen-containing groups on carbon supports favored the platinum dispersion on the Pt/C catalysts.

  • 19. Sánchez, C. G.
    et al.
    Figueiredo, R. A.
    Figueiredo, F. A. B.
    Sánchez, E. M. S.
    Arauzo, J.
    Callejo, A. G.
    Zanzi Vigouroux, Roland
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk reaktionsteknik.
    Liquid products characterization from pyrolysis and gasification: How can it be classified?2015Inngår i: Innovative Solutions in Fluid-Particle Systems and Renewable Energy Management, IGI Global , 2015, s. 167-198Kapittel i bok, del av antologi (Annet vitenskapelig)
    Abstract [en]

    In this chapter there is described a tentative of obtain and characterize pyrolysis liquids from cashew nut shell, using a suggested classification of tars. The large amount of tar definitions and measurement methods, as well as the wide spectrum of organic compounds, makes it almost impossible to capture "tars" with a clear definition. And so, in order to facilitate the study of the evolution of liquid fraction composition, the compounds have been grouped according to their chemical nature, but differently from other works, it was extended the range of compounds in order to evaluate the influence of the reactor parameters in liquid fraction compositions. It is described, as well, the pyrolysis and gasification of cashew nut shell, that has been studied in a laboratory scale reactor. It was quantified and classified the production of liquids (tar) and evaluated the final temperature influence (800, 900 and 1000 °C) and the use of N2 in pyrolysis case, and a mixture of N2 and steam or air in the gasification case. Finally, it is described the identification and quantification of tar compositions, by CG-MS and CG-FID analyzes. Around 50 different compounds have been detected in the liquid fraction obtained, most of them being present at very low concentrations and it is observed that in the pyrolysis and gasification processes, phenol and benzene were the major chemical groups, and this fact agree with others works, presented here in a bibliographic revision.

  • 20.
    Zanzi, Rolando
    et al.
    KTH, Tidigare Institutioner (före 2005), Kemiteknik. KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk teknologi.
    Sjöström, Krister
    KTH, Tidigare Institutioner (före 2005), Kemiteknik. KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk teknologi.
    Björnbom, Emilia
    KTH, Tidigare Institutioner (före 2005), Kemiteknik. KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk reaktionsteknik.
    Rapid pyrolysis of agricultural residues at high temperature2002Inngår i: Biomass and Bioenergy, ISSN 0961-9534, E-ISSN 1873-2909, Vol. 23, nr 5, s. 357-366Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper deals with rapid pyrolysis of agricultural residues such as olive waste and straw at high temperature (800 -1000degreesC) in a free-fall reactor at pilot scale. The conditions are of interest for gasification in fluidized beds where rapid pyrolysis plays an important role as first stage. The objective of the work is to study the effect of the process conditions such as heating rate, temperature and particle size on the product distribution, gas composition and char reactivity. A higher temperature and smaller particles increase the heating rate resulting in a decreased char yield. The cracking of the hydrocarbons with an increase in the hydrogen content is favoured by a higher temperature and by using smaller particles. Wood gives more volatiles and less char than straw and olive waste. The higher ash content in agricultural residues favours the charring reactions. The higher lignin content in olive waste results in a higher char yield in comparison with straw. Chars from olive waste and straw are more reactive in gasification than chars from birch because of the higher ash content.

  • 21.
    Zanzi Vigouroux, Rolando
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk teknologi.
    Björnbom, Emilia
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk reaktionsteknik.
    Grimm, Alejandro
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk reaktionsteknik.
    Biosorbentes para la remoción de cobre (II) en soluciones acuosas2005Konferansepaper (Fagfellevurdert)
  • 22.
    Zanzi Vigouroux, Rolando
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk teknologi.
    Grimm, Alejandro
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk reaktionsteknik.
    Fixed (slow-moving) bed updraft gasification of agricultural residues2006Konferansepaper (Fagfellevurdert)
    Abstract [en]

    A laboratory-scale countercurrent fixed-bed gasifier has been designed and constructed to produce datafor process modelling and to compare the gasification characteristics of several biomasses. Densified woodybiomass, birch, in form of pellets with a diameter of 8 mm and a length between 5 and 15 mm has been used as a rawmaterial for batch autothermal gasification using air as an oxidation agent. The main objectives were to study theeffect of the treatment conditions on the distribution of the products and the composition of product gas to establishthe suitability of the gasifier to produce combustible gas with sufficiently high calorific value. The influence of theair flow rates on the composition of the producer gas has been studied. The amount of the biomass used in theexperiments was varied between 1 and 4 kg and the flow rate of the oxidation agent, air, was varied from 1,1 to 2,6m3/h.

  • 23.
    Zanzi Vigouroux, Rolando
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk teknologi.
    Majari, Mehdi
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik.
    Björnbom, Emilia
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk reaktionsteknik.
    Biomass pre-treatment by torrefaction2008Konferansepaper (Fagfellevurdert)
  • 24.
    Zanzi Vigouroux, Rolando
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk teknologi.
    Sjöström, Krister
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk teknologi.
    Björnbom, Emilia
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk reaktionsteknik.
    Rapid high-temperature pyrolysis of biomass in a free-fall reactor1996Inngår i: Fuel, ISSN 0016-2361, E-ISSN 1873-7153, Vol. 75, nr 5, s. 545-550Artikkel i tidsskrift (Fagfellevurdert)
  • 25.
    Zhu, Binzhu
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk reaktionsteknik.
    Mellander, B. -E
    Fluoride-based electrolytes and their applications for intermediate temperature ceramic fuel cells2005Inngår i: Fluorinated Materials for Energy Conversion, Elsevier, 2005, s. 419-437Kapittel i bok, del av antologi (Annet vitenskapelig)
    Abstract [en]

    This chapter focuses on fluoride-based electrolytes and their applications for intermediate temperature ceramic fuel cells. Among all fuel cell (FC) technologies, the solid oxide fuel cell (SOFC) can utilize a number of different fuels. The conventional SOFCs use a ceramic electrolyte, e.g., yttria-stabilized zirconia (YSZ), and operate at high temperature, typically 1000°C. The high operating temperature puts very high demands on the materials and technology, which poses a major challenge for the further development of SOFCs into the market. For developing cost-effective SOFCs, much effort has been devoted to obtain a lower operating temperature. All these efforts have, however, limitations due to the deficiency of technology and the stability of the material. Ceramic fuel cells (CFCs) are sometimes used as a more general term for fuel cells based on ceramic materials, which have the desired properties. In the chapter, the focus is on possible proton and oxygen ion conduction in fluoride-based electrolytes that may be of interest for fundamental and applied research. Also, the focus is to develop new advanced CFCs for intermediate temperatures.

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