Low-temperature Biomass Gasification Research Articles

Sono-catalytic syngas production by low-temperature biomass gasification

Syngas holds a crucial role in diverse industrial applications, including chemical synthesis and power generation. It has been traditionally generated through high-temperature processes, such as steam reforming or biomass gasification, demanding temperatures of up to 1200 °C, which results in substantial energy consumption. Consequently, there is a growing interest in exploring alternative, low-temperature biomass gasification processes. This paper introduces an innovative method for syngas production through sono-catalytic biomass conversion at significantly lower temperatures. The approach employs a sonochemical reactor that concentrates acoustic waves to activate inertial cavitation. Furfural, a biomass-derived platform chemical, was chosen as the primary chemical for the study, showcasing the potential of sonochemical syngas production. The reaction converted furfural into various gas products, particularly a mixture of hydrogen and carbon monoxide, with the chemical reaction hypothesized to be triggered by pyrolysis during bubble collapse hot spots. The incorporation of heterogeneous metal foams into the system further enhanced furfural conversion rates. This improvement was attributed to the preferential nucleation of cavitation bubbles on the porous metal foam surface, bringing the hot spots into proximity with furfural molecules. This application of sonochemistry in furfural pyrolysis at low temperatures holds promise for a more economical approach to biomass valorization.

Autothermal CaO Looping Biomass Gasification for Renewable Syngas Production.

Biomass gasification is regarded as a promising alternative to fossil fuels for producing sustainable and clean value-added products. However, the challenges including low energy efficiency, CO2 emission, and ash agglomeration significantly delay the deployment of the technology. Herein, we first proposed a novel autothermal CaO looping biomass gasification (Auto-CaL-Gas) technology, in which CaO-based materials react with flue gas with a high concentration of CO2 (>30 vol %) to produce heat inside the gasifier, simultaneously providing energy for low-temperature biomass gasification using CO2 as a gasification agent. Upon use of this concept the syngas production exhibited a significant increase from 0.21 kg/h to 0.90 kg/h in the Aspen simulation results and more than 3-fold improvement in the experimental results.

25 バイオマス低温ガス化触媒Ni-MgO/Al_2O_3の炭素析出による失活挙動に関する研究(ガス化・燃焼(1))

25 バイオマス低温ガス化触媒Ni-MgO/Al_2O_3の炭素析出による失活挙動に関する研究(ガス化・燃焼(1))

Optimization of a Bubbling Fluidized Bed Plant for Low-Temperature Gasification of Biomass

Investigation into clean energies has been focused on finding an alternative to fossil fuels in order to reduce global warming while at the same time satisfying the world’s energy needs. Biomass gasification is seen as a promising thermochemical conversion technology as it allows useful gaseous products to be obtained from low-energy-density solid fuels. Air–steam mixtures are the most commonly used gasification agents. The gasification performances of several biomass samples and their mixtures were compared. One softwood (pine) and one hardwood (chestnut), their torrefied counterparts, and other Spanish-based biomass wastes such as almond shell, olive stone, grape and olive pomaces or cocoa shell were tested, and their behaviors at several different stoichiometric ratios (SR) and steam/air ratios (S/A) were compared. The optimum SR was found to be in the 0.2–0.3 range for S/A = 75/25. At these conditions a syngas stream with 35% of H2 + CO and a gas yield of 2 L gas/g fuel were obtained, which represents a cold-gas efficiency of almost 50%. The torrefaction process does not significantly affect the quality of the product syngas. Some of the obtained chars were analyzed to assess their use as precursors for catalysts, combustion fuel or for agricultural purposes such as soil amendment.

Cu-impregnated alumina/silica bed materials for Chemical Looping Reforming of biomass gasification gas

Raw gas derived from low-temperature biomass gasification usually contains condensable hydrocarbons referred to as “tars” as well as other hydrocarbons such as ethylene and other olefins. Reforming of these compounds via Chemical Looping Reforming has been recently proposed. In this work Cu supported on four different Al2O3/SiO2-based porous support materials were investigated for reforming of ethylene. The investigated particles were manufactured by incipient wetness impregnation of the porous support with a copper nitrate solution followed by calcination, and then tested in a small-scale fluidized bed reactor at temperatures between 600°C and 850°C. The ethylene conversion was found to be strongly inhibited by the presence of aromatics in the gas. However, it was found that Cu supported on commercial PURALOX transition alumina catalyst exhibited superior properties, with high degrees of ethylene conversion achievable even in the presence of aromatic compounds. Under the experimental conditions in this work, up to 90% ethylene conversion was obtained at T=850°C in the presence of high concentrations of benzene. For the other prepared materials, the ethylene conversion was drastically reduced when monoaromatic compounds were present in the feed.

Techno-economic analysis of biofuel production considering logistic configurations

In the study, a techno-economic analysis method considering logistic configurations is proposed. The economic feasibility of a low temperature biomass gasification pathway and an integrated pathway with fast pyrolysis and bio-oil gasification are evaluated and compared with the proposed method in Iowa. The results show that both pathways are profitable, biomass gasification pathway could achieve an Internal Rate of Return (IRR) of 10.00% by building a single biorefinery and integrated bio-oil gasification pathway could achieve an IRR of 3.32% by applying decentralized supply chain structure. A Monte-Carlo simulation considering interactions among parameters is also proposed and conducted, which indicates that both pathways are at high risk currently.

Biomass gasification using low-temperature solar-driven steam supply

A numerical modeling study on the low-temperature steam gasification process is presented to outline the possibility to drive the process with an integrated Concentrated Solar Power (CSP) plant, which provides low-temperature steam, with the aim of preserving a comparable efficiency of the new plant with traditional high-temperature biomass gasification processes. To meet this, the effective parameters and operating conditions are assessed and determined for low-temperature biomass gasification by means of sensitivity analysis, in order to find out the optimal design of the new gasifier. Crucial parameters comprise the residence time of the solid fuel and of the gas phase (leading to efficient gas–solid interactions), as well as the amount of injected oxygen and steam. Moreover, several operative parameters such as content of moisture in the biomass feedstock, size of the solid particles, equivalence ratio and structural components amount in the biomass feedstock are taken into account to optimize the operation. The molar ratio of H2/CO has been selected as a benchmark of efficiency in the process because the produced syngas would be applied in the methanol synthesis process, which needs a molar ratio of H2/CO close to the value of two. The percentage of the solid residue (weight % of the solid feedstock) has been evaluated along with the molar ratio of H2/CO in the low-temperature process to guide the re-design of the solar driven gasifier, in terms of reactor volume and amount of required oxygen and steam, which are necessary to sustain the process. The modeling and simulation to design the process have been accomplished by a comprehensive modeling package (GASDS), which includes kinetics of biomass devolatilization and pyrolysis, gasification, and secondary gas phase kinetic schemes. The gasifier, owing to its intrinsic multi-scale nature, is simulated describing both the particle and the reactor scales.

Preparation of nickel-loaded on lignite char for catalytic gasification of biomass

A novel catalyst was prepared by loading nickel on Shenli lignite char via ion-exchange. The results show that the nickel crystallite size (NCS) and specific surface area (SSA) of the catalyst significantly depended on solution pH and carbonization temperature. The catalyst prepared in pH11 at 650°C reached the maximum SSA of 236.3m2/g and the nickel particles dispersed quite well in the catalyst with a NCS of 5.6nm. The catalyst was used for corncob volatiles reforming in a two-stage fixed-bed reactor to study the effects of temperature, steam, and space velocity on gas yields and carbon distributions. It effectively improved tar decomposition at 650°C under inert atmosphere and produced a tar-free syngas in a yield of 43.9mmol/g, which is higher than that over a commercial Ni/Al2O3. The increase of the NCS during catalytic reforming above 650°C leads to the catalyst deactivation for tar decomposition. The study revealed the possibility of using Ni/char as a potential catalyst for low-temperature gasification of biomass.

Characteristics of low temperature biomass gasification and syngas release behavior using hot slag

Syngas production was achieved using low temperature biomass gasification combined with heat recovery from hot slag.

Low-Temperature Gasification of Biomass and Lignite: Consideration of Key Thermochemical Phenomena, Rearrangement of Reactions, and Reactor Configuration

This paper discusses gasification of solid fuels, such as biomass and lignite, at temperatures well below 1000 °C, which potentially realizes a loss of chemical energy (LCE) smaller than 10% but encounters difficulty in fast and/or complete solid-to-gas conversion in conventional reactor systems. First, key thermochemical and catalytic phenomena are extracted from complex reactions involved in the gasification. These are interactions between intermediates (i.e., volatiles and char), catalysis of inherent and extraneous metallic species, and very fast steam gasification of nascent char. Second, some ways to control the key phenomena are proposed conceptually together with those to rearrange homogeneous/heterogeneous reactions in series/parallel. Third, implementation of the proposed concepts is discussed assuming different types of gasifiers consisting of a single-fluidized bed, dual-fluidized bed, triple-bed circulating fluidized bed, and/or fixed (moving) bed. The triple-fluidized bed can attain gasifica...

Assessment of the Solid-Phase Adsorption Method for Sampling Biomass-Derived Tar in Industrial Environments

Low-temperature gasification of biomass is a primary process step for production of biofuels or electricity using gas-fired engines or turbines. In addition to the desired product gas, the raw gas produced through gasification inevitably contains condensable hydrocarbons, known collectively as tar. The amount and composition of the tar have relevance for the efficiencies of the downstream processes. Tar can be measured using both online and off-line methods. However, many of these methods currently lack information regarding their implementation and accuracy levels for large-scale systems. In this work, the Solid-Phase Adsorption (SPA) method for measuring tar in industrial applications is evaluated. The individual steps of the method were examined for their effects on the overall performance of the analysis. Sample collection was found to be the most prominent source of error, and this was mainly due to human factors. Omitting to determine the temperature and pressure of the sampled gas contributed to this error, as the sampled volume of gas under normal conditions could not be correctly calculated. Inconsistencies in the treatment and storage of the collected samples were shown to affect the more volatile species with boiling points similar to that of benzene. The gas chromatography (GC) analysis was performed with satisfying accuracy. However, the reliability of the estimations of the average composition and dew-point of the tar mixture were dependent upon the amount of the identified species. The current implementation of the SPA method yields values with a relative standard deviation within 10% for the majority of the compounds in a given sample. However, in line with the result of previous studies, the tar species with boiling points between those of benzene and xylene (i.e., the BTX compounds) were measured with a lower accuracy than those of heavier tars.

Preparation of Functional Materials from Natural Carbonaceous Resource

Since a low rank coal has a large amount of oxygen-containing functional groups, metal cations can be incorporated into coals by ion-exchanging. Ni-loaded brown coal was prepared in this study. A novel low temperature gasification of biomass was developed by using Ni-loaded brown coal char as a catalyst for cracking and reforming tarry materials. When Ni-loaded brown coal char was used in the gasification of wood chip, the gas yield enormously increased by 3.1 times compared with that obtained using silica sand and almost no tarry material was produced.Functional materials are recovered and prepared from spent catalyst （Ni-loaded brown coal char） and biomass char. NiO fine particles of ca. 75 nm were recovered by burning Ni-loaded brown coal char. The activated carbon and fertilizer were prepared from waste from silk industry, black liquor and poultry manure. High specific surface area of 2600～3100 m2･g-1 were achieved for activated carbon from silk worm pupa and black liquor. The resultant specific capacitance of EDLC was 47 F･g-1 which was higher than EDLC fabricated from conventional phenol resin.

1-4-2 Ni-褐炭チャー複合体を用いたバイオマスタールの低温改質(1-4 重質油、接触改質,Session 1 石炭・重質油等)

1-4-2 Ni-褐炭チャー複合体を用いたバイオマスタールの低温改質(1-4 重質油、接触改質,Session 1 石炭・重質油等)

3-1-4 Low Temperature Biomass Gasification with Pure Steam in Internally Circulating Fluidized-bed Gasifier with Catalyst Bed

3-1-4 Low Temperature Biomass Gasification with Pure Steam in Internally Circulating Fluidized-bed Gasifier with Catalyst Bed

High Tar Reduction with Porous Particles for Low Temperature Biomass Gasification: Effects of Porous Particles on Tar and Gas Yields during Sawdust Pyrolysis.

Production of tar constitutes one of the most pressing challenges in the development of low-temperature biomass gasification. As one solution to this problem, we suggest utilizing the capacitance effect of porous particles for tar-free gasification. In the present work, in order to clarify the fundamental characteristics of the capacitance effect for biomass gasification, tar yields in sawdust pyrolysis with and without porous particles were measured at 873 K and 1073 K in a lab-scale fixed bed reactor.Employment of porous particles substantially reduced the tar yield from biomass pyrolysis. Within the range studied, the tar yield without porous particles is nearly equal to the yield of carbon deposition on porous particles at 873 K. This finding indicates that porous particles can capture and hold all tar. That is, tar produced from pyrolysis is instantaneously absorbed on the surfaces of porous particles, and the residence time of tar in a gasification furnace is prolonged and then tar is pyrolyzed, carbonized and fixed on porous particles, so high tar reduction is achieved. The results of gas yield measurement show that employment of porous particles increases hydrogen yields by three times or more. There are two reasons why hydrogen yield increased. One is that the catalytic effect promotes dehydrocyclization of lower molecular weight organic gases. Another is promotion of cyclized (poly-)condensation of aromatic compounds held on porous particles. Therefore, use of porous particles is also beneficial for improving gas properties.

E201 High Tar Reduction with Porous-particles for Low Temperature Biomass Gasification : A Consideration of Mechanism of Capacitance Effect

E201 High Tar Reduction with Porous-particles for Low Temperature Biomass Gasification : A Consideration of Mechanism of Capacitance Effect