| 1. |
- Parsland, Charlotte, et al.
(författare)
-
Ba-Ni-Hexaaluminate as a New Catalyst in the Steam Reforming of 1-Methyl Naphthalene and Methane Long-Term Studies on Sulphur Deactivation and Coke Formation
- 2020
-
Ingår i: Catalysis Letters. - : Springer. - 1011-372X .- 1572-879X. ; 150, s. 1605-1617
-
Tidskriftsartikel (refereegranskat)abstract
- This work investigates the long-term performance of Ba-Ni-hexaaluminate, BaNixAl12-xO19 as a catalyst in reforming of 1-methyl naphthalene and/or methane in a model-gas simulating that from a circulating fluidized bed (CFB) gasifier during 23-29 h in a lab scale set-up, as well as the tendency for coke formation, sintering and sulphur poisoning. 1-Methyl naphthalene is used as a tar model substance. The Ba-Ni-hexaaluminate induces a high conversion of both compounds in the temperatures investigated (850 and 950 degrees C) under sulphur-free conditions. In sulphur-containing gas, the methane conversion stops at 20 ppm H2S and the reforming of 1-MNP at 850 degrees C is slightly reduced at 100 ppm.
|
|
| 2. |
|
|
| 3. |
- Parsland, Charlotte, et al.
(författare)
-
Nickel-substituted bariumhexaaluminates as novel catalysts in steam reforming of tars
- 2015
-
Ingår i: Fuel processing technology. - : Elsevier. - 0378-3820 .- 1873-7188. ; 140, s. 1-11
-
Tidskriftsartikel (refereegranskat)abstract
- This work investigates the performance of Ba–Ni-hexaaluminate, BaNixAl12 − xO19, as a new catalyst in thesteam-reforming of tars. Substituted hexaaluminates are synthesized and characterized. Steam reforming testsare carried out with both a model-substance (1-methylnaphthalene) and a slip-stream from a circulatingfluidized bed gasifier. The water–gas-shift activity is studied in a lab-scale set-up. Barium–nickel substitutedhexaaluminates show a high catalytic activity for tar cracking, and also shows activity for water–gas-shift.
|
|
| 4. |
- Einvall, Jessica, et al.
(författare)
-
High temperature water-gas shift step in the production of clean hydrogen rich synthesis gas from gasified biomass
- 2011
-
Ingår i: Biomass and Bioenergy. - : Elsevier. - 0961-9534 .- 1873-2909. ; 35:Supplement 1, s. S123-S131
-
Tidskriftsartikel (refereegranskat)abstract
- The possibility of using the water-gas shift (WGS) step for tuning the H2/CO-ratio in synthesis gas produced from gasified biomass has been investigated in the CHRISGAS (Clean Hydrogen Rich Synthesis Gas) project. The synthesis gas produced will contain contaminants such as H2S, NH3 and chloride components. As the most promising candidate FeCr catalyst, prepared in the laboratory, was tested. One part of the work was conducted in a laboratory set up with simulated gases and another part in real gases in the 100 kW Circulating Fluidized Bed (CFB) gasifier at Delft University of Technology. Used catalysts from both tests have been characterized by XRD and N2 adsoption/desorption at −196 °C.In the first part of the laboratory investigation a laboratory set up was built. The main gas mixture consisted of CO, CO2, H2, H2O and N2 with the possibility to add gas or water-soluble contaminants, like H2S, NH3 and HCl, in low concentration (0–3 dm3 m−3). The set up can be operated up to 2 MPa pressure at 200–600 °C and run un-attendant for 100 h or more. For the second part of the work a catalytic probe was developed that allowed exposure of the catalyst by inserting the probe into the flowing gas from gasified biomass.The catalyst deactivates by two different causes. The initial deactivation is caused by the growth of the crystals in the active phase (magnetite) and the higher crystallinity the lower specific surface area. The second deactivation is caused by the presence of catalytic poisons in the gas, such as H2S, NH3 and chloride that block the active surface.The catalyst subjected to sulphur poisoning shows decreased but stable activity. The activity shows strong decrease for the ammonia and HCl poisoned catalysts. It seems important to investigate the levels of these compounds before putting a FeCr based shift step in industrial operation. The activity also decreased after the catalysts had been exposed to gas from gasified biomass. The exposed catalysts are not re-activated by time on stream in the laboratory set up, which indicates that the decrease in CO2-ratio must be attributed to irreversible poisoning from compounds present in the gas from the gasifier.It is most likely that the FeCr catalyst is suitable to be used in a high temperature shift step, for industrial production of synthesis gas from gasified biomass if sulphur is the only poison needed to be taken into account. The ammonia should be decomposed in the previous catalytic reformer step but the levels of volatile chloride in the gas at the shift step position are not known.
|
|
| 5. |
- Hosseinpourpia, Reza, 1983-, et al.
(författare)
-
Utilization of different tall oils for improving the water resistance of cellulosic fibers
- 2019
-
Ingår i: Journal of Applied Polymer Science. - : Wiley-Blackwell. - 0021-8995 .- 1097-4628. ; 136:13
-
Tidskriftsartikel (refereegranskat)abstract
- This study was conducted to assess the effect of the pulping by-products crude tall oil (CTO), distilled tall oil (DTO), andtall oil fatty acid (TOFA) on dynamic water vapor sorption behavior, interfiber strength, and thermal stability of cellulosic paper-sheets.The results were compared against those obtained in cellulose papers treated with the conventional petroleum-derived hydrophobicagent hydrowax and in untreated ones. The tall oil treatments caused strong reduction in equilibrium moisture content of the paper-sheets during adsorption and desorption runs. The same trend was noticed for the hydrowax-treated papers, however, it was lesspronounced than the CTO-treated and DTO-treated samples in the relative humidity range of 75–95%. The sorption hysteresis was con-siderably decreased after the treatments. The ultimate dry-tensile strengths of the paper-sheets were significantly reduced by TOFA andhydrowax treatments, while CTO and DTO showed comparable strength as that of untreated control. The ultimate wet-strengths of thepaper-sheets were improved after the treatments. The thermal stability of the specimens was improved by the tall oil treatments, and thehydrowax-treated samples illustrated lower degradation temperature than the untreated control. The results are promising for the use oftall oils as alternative hydrophobic agents of cellulosicfiber-based products, such as wood panels and paper packaging.
|
|
| 6. |
- Parsland, Charlotte, et al.
(författare)
-
Catalytic Cracking of Biomass Tars : a Model-Study of Naphtalene Cracking with Mineral Based Catalysts
- 2010
-
Ingår i: 18th European Biomass Conference & Exhibition: From Research to Industry and Market. - : ETA Renewable Energies and WIP Renewable Energies.
-
Konferensbidrag (refereegranskat)abstract
- In the production of syngas from biomass gasification the resulting raw gas needs to be low in both tar and particulates but also optimized in its composition. Different bed materials have been studied in the purpose of catalytically reducing tars. The set-up has been in lab-scale and naphtalene has been used as a model substance. One problem that can occur when using porous and active bed materials is abrasion of the solids which causes formation of fine particles that can not be recirculated in the process cyclone. Other limiting factors are poor catalytic effectiveness and high costs for the new materials. The objective of this study is to investigate potentially cost-efficient, mechanically stable and catalytically active bed-materials.
|
|
| 7. |
- Parsland, Charlotte, et al.
(författare)
-
Effect on Catalytic Activity and Stability of the Gas Coming from a Gasifier
- 2010
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This deliverable contains both laboratory experiments and experiments where the watergas-shift catalyst has been exposed to gas and particles generated by biomass gasification.The gasification experiments took place in the 100 kWth CFB gasifier at Delft University of Technology in Delft in July 2008 and in February and August 2009.
|
|
| 8. |
|
|
| 9. |
- Parsland, Charlotte, et al.
(författare)
-
Nickel-substituted Ba-hexaaluminates as catalysts stem-reforming of tars
- 2013
-
Ingår i: CRS-2, Catalysis for Renewable sources. - Novosibirsk : Boreskov Institute of Catalysis. - 9785990255777 ; , s. 62-63
-
Konferensbidrag (refereegranskat)abstract
- Gasification of woody biomass converts the solid organic material into a gaseous product with a higher energy value and by this mean provide a more carbon neutral gaseous fuel than the common fossil ones. The produced raw gas mainly contains H2, CO, CO2, CH4, H2O and N2 together with organic (tars) and inorganic (alkali) components and fine particulates. The amount of impurities in the raw gas is dependent of the fuel properties and the gasification process technology and the quality of the resulting product gas determines its suitability for more advanced purposes. One of the major general concerns within the gasification processes is the formation of tars. Tars are a vast group of polyaromatic hydrocarbons and there are a number of definitions. On an EU/IEA/US-DOE discussion meeting in Brussels 1998, a number of experts agreed on a simplified classification of tars as “all organic contaminants with a molecular weight larger than benzene” [1]. The aim of this work is to investigate the steam reforming ability of a catalytic material not previously tested in this type of application in order to achieve an energy-efficient and high-quality gasification gas. The physical demands for an optimal tar-cracking and steam reforming catalyst is a high surface area, thermal stability, mechanical strength and a capacity to withstand high gas velocities, poisons such as H2S or NH3 and other impurities. Additionally it has to resist the process steam, as steam is well known to enhance sintering of porous materials. Nickel is a familiar catalyst for steam reforming. Hexaaluminate is a well-known catalyst support with properties that may answer to the requests of a non-abrasive, high-temperaturestable and steam-resistant catalytic material. It is a structural oxide where the general formula for the doped unit cell is MIMII(x)Al12-xO19-d where MI represents the mirror plane cation and MII is the aluminum site in the lattice where substitution may occur. MII is often a transition metal ion of the same size and charge as aluminum. MI is an ion located in the mirror plane of the structure and it is a large metal ion, often from the alkaline, alkaline earth or rare earth metal group. The stability and activity of these materials are often being related to the properties of MI and MII. The activity is highly dependent on the nature of the Al-substituted metal and partially by the nature of MII [2]. In our experiments we have tested the catalytic capacity of Ni-substituted Ba-hexaaluminates synthesised by the sol-gel method [3], both in a model set-up and in a gasification plant. In the lab-scale set-up different catalyst-formulae was tested under various temperatures for reforming of methyl-naphthalene. The results show a good catalytic activity for tar-breakdown. As expected the substitution level of Ni is clearly coupled to the reaction temperature. With the most highly substituted Ni-Bahexaaluminate at 900 °C all of the methyl-naphthalene has been broken downtogether with all of the resulting hydrocarbons. The Ni-Bahexaaluminate catalyst has recently also been tested in real process-gas.These results are still to be evaluated, but indicate a positive result.
|
|
| 10. |
- Parsland, Charlotte, et al.
(författare)
-
Nickel-substituted Barium-hexaaluminates as Catalysts in the Steam-reforming of Tars
- 2012
-
Ingår i: 20th European Biomass Conference and Exhibition. - 9788889407547
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The aim of this work is to investigate the catalytic properties, i.e. activity, selectivity and stability of nickel‐substituted Ba‐hexaaluminates for the cracking and steam‐reforming of a tar in product gas from biomass gasification. A lab‐scale set‐up has been constructed, consisting of a quartz reactor placed in a vertical oven, filled with the catalyst bed material. Methyl‐naphthalene was chosen as a tar model substance since naphthalene is considered to be especially difficult to reform, and since it is in liquid form at room temperature it is easier to handle than the solid naphthalene. A gas stream containing nitrogen gas, steam and methyl‐naphthalene was passed through the reactor and the resulting gas was analyzed by GC‐FID and GC‐TCD. Different catalyst compositions have been tested at different temperatures. The activity, stability and the product distribution was investigated as function of the temperature for the Ni‐substituted catalysts. In this study, three catalysts with different Ni‐substitution levels were used; BaNiAl11O19, BaNi1.5Al10.5O19and BaNi2Al10O19.The physical demands for an optimal cracking and steam reforming catalyst is a high surface area, thermal stability, abrasion resistance, and a capacity to withstand high gas velocities. Additionally it has to resist the process steam, as steam is well known to enhance sintering of porous materials. Hexaaluminate is a well‐known high‐temperature material with properties that may well answer to these requests. If it can be substituted to a high catalytic activity this material may well be a good candidate for steam reforming. Our results show that we have synthesized a material with the desired composition and structure. The activity tests show that we have a good reforming ability from all the catalytic materials, but with an increased activity for BaNi2Al10O19. At 1000°C all methyl‐naphthalene was decomposed in all three cases and also at 900°C for the BaNi2Al10O19. There was no char deposition in the catalyst bed and the pore size distribution was unaffected after approximately 50h on stream.In our continuing studies we will use synthesis gas instead of nitrogen and we will also examine the effect of catalyst poisons like hydrogen sulfide and chlorine.The synthesized BaNi‐hexaaluminates has proven to be very interesting candidates for a new, more resistant steam reforming catalyst in the aim of producing synthesis gas of a high quality.
|
|
