Steam Reforming Of Biomass Tar Research Articles

Steam reforming of toluene as model compounds of biomass tar by Fe–K-based biochar nano-catalysts at mild temperatures

Development of efficient catalysts for steam reforming of biomass tar is crucial for the widespread application of biomass gasification. In this work, a novel biochar nano-catalyst (BN) is conveniently prepared via one-step catalytic pyrolysis, using K and Fe to adjust the surface structure of the biochar, thereby enhancing the activity for toluene reforming. Fe–K/BN is tested in a fixed-bed reactor for steam reforming of toluene, a model compound of biomass tar, achieving a 100% toluene conversion rate at 650 °C. Fe–K/BN is activated in situ with steam to increase their specific surface area and enhance the O-containing functional groups on the surface, improving toluene adsorption and reforming. Finally, the stability of Fe–K/BN is tested in the simulated syngas, maintaining a 100% toluene conversion rate during a 26-h continuous catalytic reforming experiment. This work provides a promising strategy for the design of an active and stable catalyst for toluene reforming, which has potential for application of tar steam reforming during biomass gasification.

Perovskite-Based Catalysts for Syngas Upgrading by Intensified Steam Reforming of Biomass Tar

Perovskite-Based Catalysts for Syngas Upgrading by Intensified Steam Reforming of Biomass Tar

Interface engineering of Ce/La-doped hydrochar-supported nickel catalysts for enhanced tar reforming performance at low temperature

Catalytic reforming of biomass tar to syngas-especially under mild temperature-is an attractive albeit elusive route, necessitating the manufacture of highly efficient catalysts, in particular, from inexpensive, sustainable, and renewable resources as a prerequisite. Two interface-engineering strategies, including one-pot hydrothermal carbonization (HTC) approach and two-step HTC-impregnation method, were applied to fabricate a series of Ce/La-doped hydrochar-supported nickel catalysts, employing pinewood sawdust-derived hydrochar as the support, nickel as the active sites, and Ce or La as the promoter species. After the optimization of synthetic variables and operation conditions, the Ni0.1/Ce0.05-HC catalysts prepared by the two-step HTC-impregnation method simultaneously exhibited boosted activity, selectivity and recyclability than the Ni/HC counterpart without Ce addition as well as reported state-of-the-art catalysts in steam reforming of biomass tar at a low temperature of 600 °C. This exceptional catalytic performance was mainly attributed to the modulation of geometric structure and electronic structure of the exposed active sites by appropriate inclusion of cerium on the hydrochar-based nickel catalyst, which favored the water-gas shift, boudouard reaction and coke gasification, thereby imparting the materials with remarkable resistance against metal sintering and coke deposition during the steam reforming process. The result in this work underscores that the controlled interface between Ni species and hydrochar support by addition of Ce, which pertain to the hydrothermal processing technique, is a promising blueprint toward effective fuel production from waste biomass.

Machine learning-driven optimization of Ni-based catalysts for catalytic steam reforming of biomass tar

Biomass gasification is a promising process for producing syngas, which is widely used in various industrial processes. However, the presence of tar in syngas poses a significant challenge to biomass gasification due to the difficulties in its removal and potential downstream issues, such as clogging, slagging, and corrosion. Extensive efforts have been made to address this challenge through catalytic tar removal using various catalysts, generating a vast amount of experimental data. Processing this large dataset and gaining new insights into process optimization requires the development of efficient data analysis methods. In this study, a comprehensive database was built, encompassing a total of 584 data points and 14 input parameters collected from literature published between 2005 and 2020. Machine learning algorithms were then trained using this dataset to predict and optimize the catalytic steam reforming of biomass tar. The predicted results were found to agree well with the experimental data. The results show that the reaction temperature is the most important process parameter, with the highest relative importance of 0.24, followed by the support (0.16), additive (0.12), nickel (Ni) loading (0.08), and calcination temperature (0.07), among the 14 input parameters. This work has proposed optimal ranges for the reaction temperature (600–700 °C), Ni loading (5–15 wt%), and calcination temperature (500–650 °C). Furthermore, it was found that a larger specific surface area and higher Ni dispersion are two critical factors for selecting additives and supports. This study provides insights into key parameters for optimizing the catalytic steam reforming of biomass tar, enabling enhanced efficiency and effectiveness in biomass gasification processes.

Highly efficient steam reforming of biomass tar model compound using a high-entropy alloy-based structured catalyst

The development of efficient Ni-based catalysts for steam reforming of biomass tar is crucial for the widespread application of biomass gasification. Multimetal high-entropy alloys (HEAs) have emerged as promising catalysts that can potentially replace conventional metallic materials in various applications. In this study, we investigate NiFeCoMnCu-HEA catalysts supported on the surface of wood carbon (WC) for highly efficient steam reforming of toluene, a model compound for biomass tar. The synergistic effect between Ni and the other four metals in the HEA composition inhibits coke formation during the reaction process, while the appropriate mole ratio of Ni: (Fe + Co + Mn + Cu) reduces the particle size of HEA nanoparticles. Furthermore, the unique structure of wood carbon, with its long, interconnected, yet distorted microchannels, enhances the dispersion of active sites and improves mass transfer efficiency. As a result, the NiFeCoMnCu-HEAs/WC catalyst exhibits outstanding catalytic activity, achieving over 95% toluene conversion for 48 h at 650 °C. This performance surpasses that of the compared catalysts prepared in this work, namely NiFeCoMn/WC (39%), NiFeCoCu/WC (31%), and NiFeCo/WC (20%), underscoring the significance of the HEA structure. The findings also offer valuable insights into enhancing the performance of other nanostructures in the steam reforming of biomass tar.

Facile synthesis of low-cost Co-Cu/C alloy catalysts for hydrogen-rich syngas production from low-temperature steam reforming of biomass tar

Recovering beneficial metal ions from industrial effluents by suitable support can be an efficient and environment-friendly way to prepare specific catalysts directly. Herein, modified lignite was developed as an ion exchange material and used to prepare Co-Cu bimetallic catalysts for hydrogen-rich syngas production from steam reforming reactions. For all the catalysts studied, Co75Cu15/600 (carbonization temperature at 600 °C) exhibits the optimal catalytic activity and stability in both steam reforming of toluene and biomass tar under low temperatures. Fresh and spent catalysts were detailedly characterized to investigate the metal interactions and catalyst deactivation. The introduction of Cu contributes to the formation of Co-Cu alloy and the lower particle size of Co (4.17 nm), thereby suppressing the carbon deposition, the oxidation of metals and the change of catalyst structure after reaction. Therefore, the inexpensive and readily-available Co-Cu/C has the potential to serve as a promising catalyst for large-scale biomass gasification technology.

Preparation of highly dispersed lignite-char-supported cobalt catalyst for stably steam reforming of biomass tar at low temperature

The removal of generated tar during the biomass gasification is a serious issue. Catalytic tar cracking is one of the most efficient methods to reduce tar deposition while many common tar cracking catalysts suffer problems of serious carbon deposition and active metal sintering, especially at low temperatures. Therefore, developing catalysts with both high activity and stability is critical. In this work, we aim to prepare catalysts with a high active metal contents, a small metal particle size and a high dispersion to contribute to the highly efficient tar removal at relatively low temperatures. By adjusting the type and the concentration of the Co precursor solution when lignite is used as the carbon precursor, we prepared a series of catalysts which were then applied for both activity and stability test of the steam reforming of model tar and biomass tar. The results show that Co0.15-C2H3O2− prepared with a 0.15 M solution of Co(C2H3O2)2·4H2O achieves a Co content of about 16.0 wt% with an average particle size of about 3.77 nm and a relatively high metallic Co dispersion. For steam reforming of toluene, the catalyst achieves an almost 100 % toluene conversion at 400 °C and exhibits a high stability in the 100 h test. Moreover, Co0.15-C2H3O2−, which produces approximately 283.8 mL.gcorncob−1.gcat−1.h−1 H2 catalytically, is also active and stable in biomass tar cracking. The catalyst prepared in the present study by using the economic and simple ion-exchange method also has a well-dispersed nano-metal-loaded structure and can efficiently remove the tar at a low temperature with a high stability, which will contribute to the industrial application in the future.

Construction of high-performance NiCe-MOF derived structured catalyst for steam reforming of biomass tar model compound

High-performance and inexpensive catalysts play a large role in effective removal of biomass tar produced during biomass gasification. In this study, raw wood, with long, through, but distorted channels and a low tortuosity, was selected as a support. A layered NiCe-metal organic framework (NiCe-MOF) was grown in-situ on the surface of raw wood microchannels by using abundant surface hydroxide groups. Then, this catalyst was carbonized at 600 °C in a N2 atmosphere to obtain NiCe-MOF derived catalyst/wood carbon (NiCe-MDC/WC), which was selected as a structured reactor for the steam reforming of biomass tar. NiCe-MDC/WC achieved an excellent conversion rate of approximately 99% for toluene and a high catalytic stability of 48 h at low temperature of 550 °C. Moreover, NiCe-MDC/WC showed higher catalytic performance than Ni-MDC/WC (∼79%), crushed-NiCe-MDC/WC (∼94%), and Ni/WC (∼75%) in stability tests. These excellent results were assumed to be derived from the multilevel structure obtained from wood carbon microchannels and secondary layered MOF channels, appropriate metal-support interactions, and the presence of Ce, which could improve the dispersion of active sites and mass transfer efficiency and inhibit coke formation. Thus, such Ni-based MOF-derived structured reactors are promising for tar conversion and useful syngas production.

Ni-Fe-Ce hydrotalcite-derived structured reactor as catalyst for efficient steam reforming of toluene

Development of the efficient and inexpensive catalyst for steam reforming of biomass tar plays a significant role in the wide application of biomass gasification. In the present study, the long, through, but distorted channels with a low tortuosity of wood, which are preserved after carbonization and the Ni-Fe-Ce hydrotalcite-derived catalyst deposition, were employed for the catalytic steam reforming of biomass tar. Outstanding catalytic activity was achieved as the reactant gases flow through the Ni-Fe-Ce hydrotalcite-derived structured reactor (NiFeCe-HTc/WC), with over 98.5% toluene conversion and good stability observed at 550 °C. Moreover, the NiFeCe-HTc/WC catalyst exhibited much better catalytic performance compared to the NiFe-HTc/WC catalyst and the Ni-Fe-Ce hydrotalcite-derived catalyst supported on traditional activated carbon (NiFeCe-HTc/AC). This was because of the presence of Ce, the open but distorted channels of monolithic wood, and the graphitic carbon layer covering the active sites, which could improve the dispersion of Ni species and the mass transfer efficiency, and prevent coke formation. This work demonstrated that the Ni-Fe-Ce hydrotalcite-derived structured reactor is potentially cost-effective for a range of high-temperature applications.

Promoting effects of Fe-Ni alloy on co-production of H2 and carbon nanotubes during steam reforming of biomass tar over Ni-Fe/α-Al2O3

Fe-modified Ni/Al2O3 catalysts with Fe/Ni molar ratios of 0, 0.5, 1 and 2 were prepared to promote the co-production of H2 and carbon nanotubes (CNTs) during steam reforming of toluene as a tar model compound. After the addition of Fe, toluene conversion increased from 55.1% of Ni/Al2O3 to 73.6% of F1N1A (Fe/Ni ratio of 1), and H2 yield over F1N1A reached the maximum of more than 2000 mmol/(g-cata). Multi-walled carbon nanotubes with average diameter of 10–30 nm were generated and follow tip-growth mechanism. Compared with Ni/Al2O3, the addition of Fe remarkably increased the amount and quality of CNTs which had longer length and less tortuosity. These dual promoting effects on H2 and CNTs after the addition of Fe were attributed to the strong interaction between Ni and Fe in Fe-Ni alloy. Fe-Ni alloy had the high activity for the decomposition performance of toluene and H2O to generate more H2 and intermediates for improving the reforming reaction. Meanwhile, the high catalytic decomposition activity supplied more carbon species and the formation of Fe-Ni alloy enhanced the generation of metal carbide for promoting CNTs growth. Besides, the deposition of amorphous carbon was suppressed and the interaction between Ni particle and catalyst support was weakened after the addition of Fe, which kept the activity of catalyst and promoted the tip-growth of CNTs.

Optimization of hydrogen production from steam reforming of biomass tar over Ni/dolomite/La2O3 catalysts

Industrially, the endothermic process of steam reforming is carried out at the lowest temperature, steam to carbon (S/C) ratio, and gas hourly space velocity (GHSV) for maximum hydrogen (H2) production. In this study, a three-level three factorial Box-Behnken Design (BBD) of Response Surface Methodology (RSM) was applied to investigate the optimization of H2 production from steam reforming of gasified biomass tar over Ni/dolomite/La2O3 (NiDLa) catalysts. Consequently, reduced quadratic regression models were developed to fit the experimental data adequately. The effects of the independent variables (temperature, S/C ratio, and GHSV) on the responses (carbon conversion to gas and H2 yield) were examined. The results indicated that reaction temperature was the most significant factor affecting both responses. Ultimately, the optimum conditions predicted by RSM were 775 °C, S/C molar ratio of 1.02, and GHSV of 14,648 h−1, resulting in 99 mol% of carbon conversion to gas and 82 mol% of H2 yield.

Roles of alkali/alkaline earth metals in steam reforming of biomass tar for hydrogen production over perovskite supported Ni catalysts

Biomass steam gasification has a large potential to produce high-purity hydrogen, and perovskites are good candidates to act as catalyst supports in eliminating the biomass tar produced during reforming. However, various alkali and alkaline earth metals are contained in actual biomass, which would be released during reactions and could affect the catalytic performance of perovskite-supported catalysts. To explore potential roles of alkali and alkaline earth metals in the catalysis process, in this work, typical K, Ca and Mg were added into Ni/La0.7Sr0.3AlO3−x catalysts, and their performance in steam reforming of toluene as a model of biomass tar for hydrogen production were investigated comprehensively. Catalytic performance shows that the presence of K, Ca, and Mg leads to a better resistance to coking (a reduction of over 60%) and sintering of the Ni/perovskite catalysts utilized, and this trend becomes more pronounced as the decrease of reaction temperature. Furthermore, a series of catalyst characterizations, including XRF, XRD, SEM, TPR, TPD, and XPS were conducted to understand the action mechanism. And results reveal that the presence of K, Ca, and Mg in catalysts promotes the absorption ability of surface oxygen, which could oxidize reaction intermediates or the carbon deposited, thus enabling good reforming properties of the perovskite-supported Ni catalysts in the reforming of biomass tar.

H2S and NOx tolerance capability of CeO2 doped La1−xCexCo0.5Ti0.5O3−δ perovskites for steam reforming of biomass tar model reaction

Abstract In this paper, the La1−xCexCo0.5Ti0.5O3−δ perovskite materials were explored for steam reforming of biomass tar (SRT) reactions using toluene as a model compound at various steam-to-carbon conditions. The perovskite materials were also investigated for steam reforming reaction at 750 °C and 700 °C, respectively in the presence of poisonous compounds such as H2S and NOx. The role of Ce-doping to La1.0-Co0.5Ti0.5O3 material catalytic performances was also investigated. Among all the catalysts, catalyst composition of La0.8Ce0.2-Co0.5Ti0.5O3 displayed a stable toluene conversion of around 90% at 700 °C and S/C of 2 for a period of 22 h tested in toluene reforming reaction. Additionally, La0.8Ce0.2-Co0.5Ti0.5O3 catalyst displayed stable SRT performance in the presence of 500 ppm of NOx. On the other hand, by introducing 50 ppm of H2S during SRT reaction at 750 °C, all the catalysts showed deactivation behaviour. At the same reaction temperature regeneration of about 90% of activity was observed for La0.8Ce0.2-Co0.5Ti0.5O3 catalyst. Overall, the best catalytic performance of La0.8Ce0.2-Co0.5Ti0.5O3 catalyst is due to the availability of higher amount of surface Co species and oxygen vacancies than other catalysts. From XRD analysis of calcined, reduced and spent catalysts, the presence of perovskite structural phase was observed for all the La-based catalysts and negligible Co species agglomeration observed during SRT reaction. CO2-TPD studies showed that the basicity of La0.8Ce0.2-Co0.5Ti0.5O3 and La1.0Co0.5Ti0.5O3 catalysts was higher compared to other perovskite compositions. TGA and Raman analysis revealed, suppressed rate of carbon deposition for all the Ce-contained materials and the deposited carbon was mostly amorphous in nature. Finally, low carbon deposition rate and high surface oxygen mobility were the possible reasons for La0.8Ce0.2-Co0.5Ti0.5O3 catalyst’s stable catalytic performance over other catalysts.

Incinerator bottom ash derived from municipal solid waste as a potential catalytic support for biomass tar reforming

Environment-friendly and sustainable routes for municipal solid waste (MSW) incineration bottom ash (IBA) recycling and utilization is one of the major concerns for the urbanized countries like Singapore. In this research paper, the possibility of bulk utilization of MSW-IBA as a catalyst support material has been explored for sustainable syn-gas production. The change in the texture of the IBA with simple hydrothermal treatment using NaOH has also been investigated. Furthermore, with hydrothermal treatment for 24 h at 180 °C, the texture of raw IBA with respect to basicity, surface area, total pore volume and reducibility was greatly improved. These textural properties are highly significant for a material to be utilized as a catalyst or catalytic supports for reforming applications. Ni supported on hydrothermally treated IBA was tested for steam reforming of biomass tar reforming reaction between 700 °C and 800 °C at relatively low steam-to-carbon ratio of 2. Among all the catalysts, Ni supported on IBA hydrothermally treated for 24 h gave stable toluene conversion (of 40%) at 700 °C with reduced coke formation (of 7.5 mgC/g·h) than other catalysts. The superior catalytic performance of this catalyst is mainly due to the presence of high amounts of surface Ni° species and improved reducibility and basicity properties among all. The Raman, DT/TGA and XRD analyses on spent catalysts revealed the deposited carbon during steam reforming of tar reaction is majorly amorphous. Due to this, the deposition of carbon did not show any kind of deactivation within the catalyst testing period.

Investigation of Ni/Fe/Mg zeolite-supported catalysts in steam reforming of tar using simulated-toluene as model compound

Abstract Catalytic performance of Ni/zeolite, Ni-Fe/zeolite, and Ni-Fe-Mg/zeolite catalysts were investigated in steam reforming of toluene as a biomass tar model compound to explore promotional effect of MgO and Fe on Ni/zeolite support. The Ni-Fe-Mg/zeolite catalysts with optimum metallic composition showed higher catalytic performance over corresponding monometallic Ni and Fe catalysts and Ni-Fe/zeolite (bimetallic) catalysts. Addition of Mg to Ni-Fe/zeolite catalyst enhanced the tar reforming reactions and increased the carbon deposition tolerance. The results suggest that Ni-Fe/zeolite and Ni-Fe-Mg/zeolite catalysts have great potential for application in the steam reforming of biomass tar.

Removal of biomass tar by steam reforming over calcined scallop shell supported Cu catalysts

In this study, the main purpose is to develop low-cost catalysts with high activity and stability for high quality syngas production via steam reforming of biomass tar in biomass gasification process. The calcined waste scallop shell (CS) supported copper (Cu) catalysts are prepared for steam reforming of biomass tar. The prepared Cu supported on CS catalysts exhibit higher catalytic activity than those on commercial CaO and Al2O3. Characterization results indicate that Cu/CS has a strong interaction between Cu and CaO in CS support, resulting in the formation of calcium copper oxide phase which could stabilize Cu species and provide new active sites for the tar reforming. In addition, the strong basicity of CS support and other inorganic elements contained in CS support could enhance the activity of Cu/CS. The addition of a small amount of Co is found to be able to stabilize the catalytic activity of Cu/CS catalysts, making them reusable after regeneration without any loss of their activities.

Pb-205 バイオマスタールの水蒸気改質用酸化物触媒の反応挙動の解明(ポスターセッション2:2.技術,研究発表,(ポスター発表))

Pb-205 バイオマスタールの水蒸気改質用酸化物触媒の反応挙動の解明(ポスターセッション2:2.技術,研究発表,(ポスター発表))

3-1-1 Steam reforming of biomass tar over Ni/MCM-41 catalyst at low temperatures

3-1-1 Steam reforming of biomass tar over Ni/MCM-41 catalyst at low temperatures

A High-Performance, Low-Tortuosity Wood-Carbon Monolith Reactor.

A highly efficient 3D wood-derived carbon monolith reactor with a low tortuosity is demonstrated for high-temperature reaction applications, using catalytic steam reforming of biomass tar as the model system. Outstanding catalytic activity is achieved as the reactant gases flow through this 3D natural wood-derived catalyst, where over 99% toluene conversion and good stability at 700 °C are observed.

P-09 Long Time Operating of Iron-Based Catalyst for Steam Reforming of Biomass Tar

P-09 Long Time Operating of Iron-Based Catalyst for Steam Reforming of Biomass Tar