Biomass Tar Research Articles

One-step synthesis of biomass activated char supported copper nanoparticles for catalytic cracking of biomass primary tar

Activated char supported copper nanocatalysts were synthesized directly by one-step pyrolysis of CuCl2 impregnated biomass together with ZnCl2 as activation agent and applied to the cracking of biomass primary tar in a dual-stage reactor. The characterization of the obtained catalysts using XRD, SEM-EDX, TEM and N2 adsorption-desorption indicated CuCl2 can be reduced to Cu0 nanoparticles as active sites, and the presence of ZnCl2 can significantly enlarge the surface area of biomass char to improve the dispersion of copper nanoparticles. A large number of micropores and mesopores were formed during the synthesis process, which also helps to adsorb tar molecules and prolong the reaction time. The prepared nanocatalysts exhibited excellent catalytic activity in the cracking of primary biomass tar as a result of the combining effect of CuCl2 and ZnCl2, and a high tar conversion efficiency of 94.5% was obtained using RHC-1.0Cu1·0Zn at 800 °C. The yields of H2, CH4, CO and the total gas product increased significantly as a result of the tar reforming reactions using the activated char supported catalysts. GC-MS analysis illustrated that the biomass primary tar was mainly decomposed into oxygenated aromatic compounds and light tar compounds over the biomass char supported copper nanocatalysts.

Thermo-catalytic decomposition of biomass tar models through microwave irradiation

Producer gas from biomass gasification is tormented by the demeanour of tar which causes pipe blockages, plugging, corrosion, and catalyst deactivation. Thermo-catalytic tar models decomposition via microwave irradiation has been shown to be effective method in reducing tar from producer gas. This study, toluene and naphthalene were used as tar models with N2 as the carrier gas followed by the use of spurious producer gas. Thermal and catalytic decomposition of tar models with over a wide temperature range from 850 °C to 1,200 °C and 650 °C to 900 °C, respectively, at residence time of 0.24 - 0.5 s. In term of catalytic treatment, Ni/Mg/Al2O3 which the improved catalyst was used to remove both of tar models too. The results showed that the high tar removal efficiency both of thermal and catalytic cracking method. In addition, toluene was much easier to be reduced than naphthalene.

5 Ultramicropore-rich renewable porous carbon from biomass tar with excellent adsorption capacity and selectivity for CO2 capture

Biomass tar was a conspicuous hazardous byproduct from biomass gasification, and it has become a great challenge in the development of biomass energy technology. Here, we proposed the facile one-step synthesis of highly porous carbon using biomass tar as feedstock, porous CaO as a template, and KOH as an activation agent. Following a simultaneous activation-template-carbonization process, the product displayed tunable porosity and high specific surface area (up to 2424 m2 g−1). When applied to CO2 capture, the ultramicropores of this carbon material played a significant role in enhancing the CO2 affinity. In particular, the adsorbent synthesized with biomass tar:CaO:KOH in 1:2:3 wt ratio exhibited the high CO2 capture capacity of 5.03 and 3.13 mmol g−1 at 273 K and 298 K (1.20 mmol g−1 at 0.15 bar), respectively, perfect cyclic regeneration property (95% retention) and excellent initial isosteric heat of adsorption (48.55 kJ mol−1). The CO2/N2 selectivity from Henry’s Law and ideal solution adsorption theory reached 26.3 and 15.4 at 273 K, and 32.4 and 19.7 at 298 K, respectively.

Synthesis of biomass tar-derived foams through spontaneous foaming for ultra-efficient herbicide removal from aqueous solution

Pyrolysis is one of the most important approaches to convert waste biomass into renewable energy and biomaterials, and the tar is the inevitable by-product of this process. In this study, carbon foams were prepared innovatively with biomass tar as the precursor through spontaneous gas foaming approach and used for dicamba removal from aqueous solution. The results showed that prepared carbon foams had unique properties including rich microporous structure and high specific surface area (reaching 1667 m2/g). In addition, the prepared carbons had high thermal stability due to the high graphitic degree. The adsorption results indicated that pH showed a great effect on the adsorption of dicamba onto the prepared carbon foams. The carbon foam exhibited ultra-fast dicamba removal and ultra-high adsorption capacity of 891.74 mg/g at room temperature. The adsorption process was well described by pseudo-second-order kinetics and Langmuir isotherm models. The thermodynamic study indicated dicamba adsorption onto the prepared carbon foams was a spontaneous and exothermic process. In addition, the good reusability from recovery test demonstrated that the prepared carbon foams had promising potential for dicamba removal from aqueous solution.

Catalytic Steam Reforming of Biomass-Derived Tar over the Coal/Biomass Blended Char: Effect of Devolatilization Temperature and Biomass Type

Catalytic tar steam reforming over char was conducted in a two-stage fixed-bed reactor. This reactor was divided into two zones: the “devolatilization zone”, where the biomass tar is released, and ...

Synthesis of graphitic mesoporous carbon supported Ce-doped nickel catalyst for steam reforming of toluene

Graphitic mesoporous carbon (GMC) supported Ce-doped nickel catalyst was prepared by a simple incipient wetness impregnation and calcination method. The catalytic performance of the prepared catalyst was tested by catalytic steam reforming of toluene (a biomass tar model compound). Compared with mesoporous SBA-15 supported catalyst, the GMC supported catalyst has a higher toluene conversion efficiency of 98% at 700 °C and remained stable during 24 h of continuous reaction. The excellent catalytic performance is mainly attributed to the better dispersion of Ni nanoparticles on GMC support and the reduced carbon deposition because of the Ce-doping.

Catalytic synthesis and simultaneous co-doping of hierarchically porous carbon with in-situ coated graphene from biomass tar as efficient catalyst for ORR

Although oxygen reduction reaction (ORR) plays a key role in the cathodic part of many emerging energy conversion devices, it has naturally suffered from sluggish kinetics and high overpotential. We here report the facile synthesis of Fe-N co-doped carbon with a hierarchical porosity and in-situ formed graphene from biomass tar using urea as the nitrogen dopant, and FeCl3 as the porogen, catalyst, and Fe dopant. This exhibited an ORR catalytic activity comparable to that of a Pt/C catalyst in relation to its onset potential, limited diffusion current, and stability under an alkaline condition. It was found that the excellent catalytic performance should have originated from its large specific surface area, abundant active centers, and long-term conductive network. This renewable non-noble-metal catalyst may serve as an appropriate alternative to conventional noble catalysts in ORR-based techniques, and will also encourage investigations on the use of biomass tar for advanced materials toward various ends.

Layered uniformly delocalized electronic structure of carbon supported Ni catalyst for catalytic reforming of toluene and biomass tar

Lignite rich in oxygen-containing species (OCSs) was employed as perfect ion-exchange material for high activity catalyst preparation. HCl treatment Shengli lignite (HSL) selectively removed the organic salt and improved capability of ion exchange. In this paper, highly desirable and layered carbon supported Ni catalyst was prepared by modified lignite. Thanks to the excellent role of Ni (1 1 1) plane and porous layered graphene-like delocalized electronic structure, specific structure of lignite provides an exchange platform in facilitating the Ni electron transfer during the catalytic reaction process. Ni loaded on HSL (Ni/HSL) showed the great catalytic activity and stability for reforming of toluene and biomass tar. Ni/HSL prepared at 650 °C shows the great activity and stability for toluene steam reforming (TSR) and biomass tar reforming (BTR). A series of instruments (XRD, SEM, TEM, H2-TPR, XPS, CO pulse adsorption, etc.) were employed for characterization. Based on these significant characterizations of catalyst, calculation of turnover frequency (TOF), and results of conversion of toluene and corncob tar. The results revealed the layered delocalized electronic structure of Ni/HSL, which has lower activation energy than other reported catalysts. Uniform dispersed catalyst was synthesized successfully for reforming of toluene and biomass tar.

Ni-based catalysts for steam reforming of tar model derived from biomass gasification

Tar formation during biomass gasification is a major barrier to utilise the produced syngas, which clogs processing equipment. In the present study, steam reforming of gasification-derived tar (phenol, toluene, naphthalene, and pyrene) was catalysed by Ni/dolomite, Ni/dolomite/Al2O3, Ni/dolomite/La2O3, Ni/dolomite/CeO2, and Ni/dolomite/ZrO2 for hydrogen production. The steam reforming experiment was conducted in a fixed bed reactor at 700 °C and the steam-to-carbon molar ratio of 1 under atmospheric pressure. After the catalytic test, the spent catalysts were characterised by thermogravimetric analysis and variable-pressure scanning electron microscope. The aim of this study is to investigate the catalytic activity of Ni-based catalysts in terms of tar conversion and their deactivation characteristic. The current results revealed that all the catalysts showed almost full conversion of tar (98.8%-99.9%) and considerably low amount of coke deposited in the form of amorphous and filamentous carbon (15.9-178.5 mg gcat-1). Among the catalysts studied, Ni/dolomite/La2O3 gave the highest catalytic activity for steam reforming of gasified biomass tar and lowest coke formation.

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.

NiCo@NiCo phyllosilicate@CeO2 hollow core shell catalysts for steam reforming of toluene as biomass tar model compound

Developing sintering and carbon resistant tar removal catalysts is crucial for biomass gasification technology. Herein, for the first time, NiCo@NiCo phyllosilicate@CeO2 hollow core shell catalysts have been designed for steam reforming of toluene (SRT) as the biomass tar model compound. They show both good catalytic activity and stability within 45 h of time on stream due to their high sintering resistance of NiCo because of the strong interactions between NiCo and CeO2, high metal exposure as a result of the high specific surface area, high surface metal concentration as well as the high oxygen vacancies as evidenced from the H2-Temperature-programmed reduction (H2-TPR), H2 chemisorption and X-ray photoelectron spectroscopy (XPS) characterizations respectively. Additionally, the synergistic effect between Ni and Co further improves their carbon resistant property. By comparison, Co@Co phyllosilicate@CeO2 catalysts perform the lowest toluene conversion and stability mainly due to their structural instability during reaction resulting from their high Si/Co ratio, leading to their low specific surface area and Co exposure. The outstanding SRT performance of NiCo@NiCo phyllosilicate@CeO2 catalysts indicates their promising application for steam reforming of biomass tar reaction.

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.

Removal of Toluene as a Biomass Tar Surrogate in a Catalytic Nonthermal Plasma Process

In this study, a packed-bed dielectric barrier discharge (DBD) reactor was developed to investigate the removal of biomass tar in a fuel gas atmosphere. Toluene was used as the tar surrogate, and t...

Numerical Simulation of Flow and Heat Transfer Characteristics in Biomass Feeder

In this paper, designed a swirling feeder for biomass tar, The numerical simulation of flow characteristics and temperature field heat transfer characteristics of the internal flow field was performed. Mixture multiphase flow model and Reynolds stress turbulence model are used, in the case of different feed flow ratios, Solved the internal flow field, concentration field and temperature field; Through research shows that when the flow ratio i = 0.6 ∼ 0.8, Biomass tar can enter the reactor through the feeder without causing coking.

Catalytic cracking of tar derived from the pyrolysis of municipal solid waste fractions over biochar

The tars derived from the pyrolysis of four typical municipal solid waste fractions at 600 °C, namely pine wood (PW), tryptone (TP), polyethylene (PE) and polyvinyl chloride (PVC), were characterized and then catalytically cracked by activated biochar catalyst (ABC) at 700–900 °C. The ABC was produced from the pyrolysis of pine wood at 800 °C for 1 h, then activated by CO2 at 900 °C for 20 min. The results showed that O-containing species, N-containing species, chain hydrocarbons and polycyclic aromatic hydrocarbons (PAHs) were the main products in the raw tar from the pyrolysis of PW, TP, PE and PVC, respectively. The tar cracking efficiency by ABC was ordered as PW>TP>PE>PVC, which indicated that the biomass tars were easier to be converted by ABC than plastic tars. The highest tar conversion of 98.7% was achieved for PW at 900 °C. Besides, N-containing tars were more stable than O-containing tars. The coke deposition on the ABC was more serious after the cracking of plastic tars (PE and PVC) than that of biomass tars (PW and TP). After the catalytic cracking of TP and PVC tars at 900 °C, the nitrogen and chlorine contents in ABC increased by 3 times and 10.5 times, respectively.

High catalytic performance of Fe-Ni/Palygorskite in the steam reforming of toluene for hydrogen production

The inexpensive and abundant material, palygorskite, was used as a promising catalyst support to prepare Fe-Ni/Pal catalysts. Catalytic steam reforming of toluene as a biomass tar model compound over these catalysts was investigated in a fixed-bed reactor under different parameters, including reaction temperatures and S/C molar ratios. The stability and lifetime of Fe3Ni8/Palygorskite catalyst was evaluated under optimal conditions and its kinetic parameters were determined as well. The fresh and used catalysts were characterized using X-ray diffraction (XRD), H2 temperature-programmed reduction (H2-TPR), transmission electron microscopy (TEM), and Raman spectra. The results showed that the Fe3Ni8/Palygorskite catalyst with high dispersion was successfully prepared and exhibited superior catalytic performance compared with those of the monometallic catalysts (Fe3/Palygorskite and Ni8/Palygorskite) and the bare Palygorskite. Increasing the reaction temperature from 500 °C to 700 °C was beneficial for the toluene conversion and gaseous yields. The catalytic activity of Fe3Ni8/Palygorskite varied distinctly with the increase of S/C molar ratio and reached maximum at the the S/C molar ratio of 1.0. The apparent activation energy of 41.55 kJ mol−1 and the pre-exponential factor of 1.35 × 103 m3 kg−1 h−1 were obtained for Fe3Ni8/Palygorskite in kinetic studies under optimal reaction conditions, respectively. The carbon deposition analysis of the used catalysts revealed that the formation of graphitic carbon rather than amorphous carbon was the main reason for the deactivation of Fe3Ni8/Palygorskite catalysts. When ceased the injection of steam into the reaction system, the graphitic carbon would be accelerating formed on the surface of the Fe3Ni8/Palygorskite and decreased its catalytic activity for toluene conversion. But owing to the water gas shift reaction, the catalytic activity of Fe3Ni8/Palygorskite seemed to recover gradually to its optimum.

N-doped carbon quantum dots as fluorescent probes for highly selective and sensitive detection of Fe3+ ions

To investigate the effect of nitrogen on the photoluminescence properties of carbon quantum dots (CQDs), N-doped carbon quantum dots (N-CQDs) were synthesized by one-step hydrothermal treatment using biomass tar as the carbon precursor. As an inevitable organic pollutant, the unsaturated bonds in biomass tar, such as carboxylic acids, aldehydes, and aromatics, are favorable for formation of the graphitic carbon lattice. The obtained N-CQDs are spherical with an average particle size of 2.64nm and the crystal lattice spacing is 0.25nm, corresponding to the (100) facet of graphitic carbon. The N-CQDs emit bright blue photoluminescence under 365nm ultraviolet light, and they have excellent water solubility and stability with a high quantum yield of 26.1%. Coordination between the functional groups on the N-CQD surface and Fe3+ ions is promoted because of the improved electronic properties and surface chemical reactivity caused by N atoms, leading to a significant fluorescence quenching effect of the N-CQDs in the presence of Fe3+ ions with high selectivity and sensitivity. There is a linear relationship between ln (F0/F) and the Fe3+ concentration in the N-CQD concentration range 0.06–1400μmol/L with a detection limit of 60nmol/L, showing that the N-CQDs have great potential as a fluorescent probe for Fe3+ detection.

Kinetic and experimental characterizations of biomass pyrolysis in granulated blast furnace slag

With the objective of abating the energy crisis and greenhouse gas emissions, biomass pyrolysis to recover waste heat from granulated blast furnace (BF) slag was investigated via thermogravimetric and continuous fixed-bed experiments. The results showed that the mass conversion of biomass pyrolysis increased with the increasing heating rate. At the same time, a higher gas yield and lower heating value (LHV) and concentrations of H2 and CO were obtained with the increasing temperature. Granulated BF slag can promote the pyrolysis and reforming of biomass tar, increasing the gas yield and LHV and H2 concentration. Thus, granulated BF slag not only provided heat for the pyrolysis reaction but also promoted the pyrolysis and reforming of biomass tar, which might block and corrode pipes in practical production. The shrinking core model (R2) selected using a two-step calculation method interpreted the biomass pyrolysis in granulated BF slag. The reaction activation energy ranged from 60.743 kJ/mol to 65.963 kJ/mol as the heating rate decreased from 40 K/min to 10 K/min.

Strongly Fluorescent Carbon Quantum Dots from Biomass Tar as Highly Selective and Sensitive Probe for Fe3+ Detection

Nonhazardous and value-added utilization of biomass tar remains a great challenge in biomass gasification development. Herein, both model compounds and real biomass tar were for the first time tested as the carbon source for carbon quantum dots, where the resultants demonstrated excellent monodispersibility and strong fluorescence, quantum efficiency up to 53% and 43% were achieved. Moreover, the real tar-derived CQDs further revealed as a highly selective and sensitive probe for Fe[Formula: see text], indicating its great potential ion sensing. It is expected that this work would open up a new strategy for biomass tar valorization.

Chemical looping reforming of toluene as a biomass tar model compound over two types of oxygen carriers: 2CuO-2NiO/Al2O3 and CaFe2O4

Chemical looping reforming/gasification of toluene, the model compound representing biomass tar, was studied by using two oxygen carriers, 2CuO-2NiO/Al2O3 (molar ratio) and CaFe2O4. Their reaction performances were evaluated in a TG-FTIR and a laboratory-scale fixed bed reactor. The active lattice oxygen of the 2CuO-2NiO/Al2O3 oxygen carrier demonstrated excellent reactivity and completely oxidized toluene to CO2 at 600–700 °C, while the fixed bed reactor data indicated that 2CuO-2NiO/Al2O3 oxygen carrier could catalyze the cracking of toluene to produce H2 after loss of lattice oxygen. The CaFe2O4 oxygen carrier exhibited a good performance of chemical looping partial oxidation of toluene to CO and H2 with a fairly high reactivity. Over CaFe2O4 oxygen carrier, the CO and H2 dominated reaction products in the temperature range of 800–900 °C except at the startup stage. Catalytic cracking of toluene by CaFe2O4 to produce H2 was also observed after partial loss of lattice oxygen. Stable performance of CaFe2O4 with high reactivity to syngas (CO and H2) was demonstrated during a 3-cyle test in the fixed bed reactor. After reduction of action with toluene, scanning electron microscopy (SEM) and X-ray diffraction (XRD) indicated that 2CuO-2NiO/Al2O3 was reduced to metallic copper and nickel with the mixture of NiAl2O4, and CaFe2O4 was reduced to metallic iron and CaO. In summary, two oxygen carriers displayed high toluene conversion at the beginning stage and the conversion of toluene increased to about 100% in the subsequent stage.