Bio-syngas Production Research Articles

A comparison of the bio-syngas production costs from biomass using gas post-treatment of water scrubber and Selexol

A comparison of the bio-syngas production costs from biomass using gas post-treatment of water scrubber and Selexol

Catalytic Upgrading of Biomass-Gasification Mixtures Using Ni-Fe/MgAl2O4 as a Bifunctional Catalyst.

Biomass gasification streams typically contain a mixture of CO, H2, CH4, and CO2 as the majority components and frequently require conditioning for downstream processes. Herein, we investigate the catalytic upgrading of surrogate biomass gasifiers through the generation of syngas. Seeking a bifunctional system capable of converting CO2 and CH4 to CO, a reverse water gas shift (RWGS) catalyst based on Fe/MgAl2O4 was decorated with an increasing content of Ni metal and evaluated for producing syngas using different feedstock compositions. This approach proved efficient for gas upgrading, and the incorporation of adequate Ni content increased the CO content by promoting the RWGS and dry reforming of methane (DRM) reactions. The larger CO productivity attained at high temperatures was intimately associated with the generation of FeNi3 alloys. Among the catalysts’ series, Ni-rich catalysts favored the CO productivity in the presence of CH4, but important carbon deposition processes were noticed. On the contrary, 2Ni-Fe/MgAl2O4 resulted in a competitive and cost-effective system delivering large amounts of CO with almost no coke deposits. Overall, the incorporation of a suitable realistic application for valorization of variable composition of biomass-gasification derived mixtures obtaining a syngas-rich stream thus opens new routes for biosyngas production and upgrading.

Experimental investigations of bio-syngas production using microwave pyrolysis of UAE’S palm date seed pits

Energy has been essential for the human society, and since the 1700s, the growing need for energy has outstripped the available sources owing to social development and increased use of machines. Biomass as a renewable resource of energy has attracted current research interest. Thermochemical conversion of waste biomass into bio-syngas supports energy needs and provides a better solution for waste management as the economic appraisal of any nation depends on the available energy. In this paper, microwave pyrolysis of the most abundant agricultural waste found in UAE, the Allig date seed pits, is evaluated for bio-syngas production. A full factorial parametric study was performed based on different particle sizes, microwave powers and moisture contents. The syngas yield and the pyrolysis temperature were experimentally analyzed. The experimental result revealed that the maximum bio-syngas was attained at a1000W microwave power, 467 μm particle size and a dry sample, which were producing CH4 and CO bio-gas yield with 21 vol% and 15 vol% respectively. Hence, Allig date seed pits as a biomass in the microwave pyrolysis process may be a promising source of sustainable power for industrial and consumer applications.

Feasibility Study of Biomass Gasification Integrated with Reheating Furnaces in Steelmaking Process

This paper investigates the integration of biosyngas production, reheating furnace and heat recovery steam cycle, in order to use biosyngas directly as fuel in the furnace. A system model was developed to evaluate the feasibility of the proposed system from the perspective of heat and mass balance. To particularly study the impacts of fuel switching on the heating quality of the furnace, a three-dimensional furnace model considering detailed heat transfer processes was embedded into the system through an Aspen PlusTM user defined model. The simulation results show that biosyngas is suitable for direct use as fuel for reheating furnaces. Should CO2 capture be considered in the proposed system, it has a potential to achieve the capture without external energy input which results in so-called negative emissions of CO2.

Assessing the Effects of Different Process Parameters on the Pyrolysis Behaviors and Thermal Dynamics of Corncob Fractions

The influence of heating rate, gas flow, and biomass particle size on the pyrolysis and thermal dynamics of corncobs (CC) was investigated experimentally using the quantitative method of thermogravimetric analysis (TGA) coupled with mass spectrometry (MS), and the obtained results were compared in depth. For the examined heating rates of 5, 10, and 20 °C/min, the CC pyrolysis at higher heating rates resulted in a more complete decomposition. The initial pyrolysis temperature decreased when gas flow was increased from 30 to 90 mL/min, whereas the weight loss increased. Particle sizes (d ≤ 74 μm, 74 μm < d ≤ 154 μm, 154 μm < d ≤ 280 μm, and 280 μm < d ≤ 450 μm) had pronounced effects on the thermal decomposition and bio-syngas compounds (CO, CO2, CH4, and H2) distribution. The emission intensities of most the gaseous products increased at the elevated heating rate, while they decreased with increasing gas flow. In sum, the pyrolysis of CC particles of 154 μm < d ≤ 280 μm under 20 °C/min and in a gas flow of 30 to 60 mL/min was the most appropriate for bio-syngas production in industrial applications.

Quantitative Investigation on Pyrolytic Behaviors of Agricultural Residues from Rice Husk and Various Performances of Their Relevant Ash Residues

In this study, the thermal process behavior of rice husk as a sustainable feedstock for bio-syngas production and the physicochemical properties of rice husk ash generated from thermal process as possible precursors for utilizations were intensively investigated. A preliminary analysis of the influences of heating rate on kinetics and on the formation of bio-syngas was also performed. The thermogravimetric results of rice husk indicate that its decomposition occurs in four stages, and the main weight loss occurs within 210–400°C. The emission intensities of CO, CO2, CH4, and H2 at 20°C/min are much higher than those of 5°C/min, indicating that pyrolysis at higher heating rates is more suitable for bio-syngas production. Chemical and phase analysis exhibits the presence of cristobalite, quartz, and tridymite as the major crystal phases of SiO2, which reveals the potential of rice husk ash as an alternative for silicon compounds. The porous structure analysis indicates that carbon residues developed from rice husk ash are good candidates for activated carbon production. Through analyzing its thermal properties, the internal reactions occurring within ash particles are predicted accurately, which is helpful to better understand the transformation and fusion mechanism of inorganic components in the complex-composition ash.

Bio-syngas production from agro-industrial biomass residues by steam gasification

This study evaluated the steam gasification potential of three residues from Brazilian agro-industry by assessing their reaction kinetics and syngas production at temperatures from 650 to 850°C and a steam partial pressure range of 0.05 to 0.3bar. The transition temperature between kinetic control and diffusion control regimes was identified. Prior to the gasification tests, the raw biomasses, namely apple pomace, spent coffee grounds and sawdust, were pyrolyzed in a fixed-bed quartz tubular reactor under controlled conditions. Gasification tests were performed isothermally in a magnetic suspension thermobalance and the reaction products were analyzed by a gas chromatograph with TCD/FID detectors. According to the characterization results, the samples presented higher carbon and lower volatile matter contents than the biomasses. Nevertheless, all of the materials had high calorific value. Syngas production was influenced by both temperature and steam partial pressure. Higher concentrations of H2 and CO were found in the conversion range of 50–80% and higher concentrations of CO2 in conversions around 10%, for all the gasified biochars. The H2/CO decreased with increasing temperature, mainly in kinetic control regime, in the lower temperature range. The results indicate the gasification potential of Brazilian biomass residues and are an initial and important step in the development of gasification processes in Brazil.

Dark fermentation biorefinery in the present and future (bio)chemical industry

Dark fermentation, also known as acidogenesis, involves the transformation of a wide range of organic substrates into a mixture of products, e.g. acetic acid, butyric acid and hydrogen. This bioprocess occurs in the absence of oxygen and light. The ability to synthesize hydrogen, by dark fermentation, has raised its scientific attention. Hydrogen is a non-polluting energy carrier molecule. However, for energy generation, there is a variety of other sustainable alternatives to hydrogen energy, e.g. solar, wind, tide, hydroelectric, biomass incineration, or nuclear fission. Nevertheless, dark fermentation appears as an important sustainable process in another area: the synthesis of valuable chemicals, i.e. an alternative to petrochemical refinery. Currently, acetic acid, butyric acid and hydrogen are mostly produced by petrochemical reforming, and they serve as precursors of ubiquitous petrochemical derived products. Hence, the future of dark fermentation relies as a core bioprocess in the biorefinery concept. The present article aims to present and discuss the current and future status of dark fermentation in the biorefinery concept. The first half of the article presents the metabolic pathways, product yields and its technological importance, microorganisms responsible for mixed dark fermentation, and operational parameters, e.g. substrates, pH, temperature and head-space composition, which affect dark fermentation. The minimal selling price of dark fermentation products is also presented in this section. The second half discusses the perspectives and future of dark fermentation as a core bioprocess. The relationship of dark fermentation with other (bio)processes, e.g. liquid fuels and fine chemicals, algae cultivation, biomethane–biohythane–biosyngas production, and syngas fermentation, is then explored.

Integrated aqueous-phase glycerol reforming to dimethyl ether synthesis—A novel allothermal dual bed membrane reactor concept

Dimethyl ether (DME) production from glycerol via an integrated process involving aqueous-phase glycerol reforming to biosyngas combined with DME synthesis into an allothermal dual-bed membrane reactor was analyzed numerically. The system combines two separate enclosures, a fixed-bed water perm-selective membrane DME synthesis unit and a gas–liquid–solid fixed-bed aqueous-phase glycerol reforming unit. Exothermic DME synthesis provides heat to endothermic aqueous-phase glycerol reforming which in return produces biosyngas for DME synthesis. The two-scale, non-isothermal, unsteady-state model developed for the integrated system accounts for a detailed gas/gas–liquid dynamics whereupon DME synthesis/aqueous-phase glycerol reforming kinetics, thermodynamics, thermal effects and variable gas flow rate due to chemical/physical contractions were accounted for. The integrated process is intended to minimize abundant glycerol by-product streams via an energy efficient alternative for producing DME. It presents an opportunity to improve the economics of green DME synthesis by cost reduction of biosyngas production while improving thermal efficiency of DME synthesis.

Biosyngas production by autothermal reforming of waste cooking oil with propane using a plasma-assisted gliding arc reactor

Biosyngas production from renewable sources such as biomass has no impact on atmospheric CO 2 levels. In this work, the initial tests results are presented for the conversion of waste cooking oil (WCO) to biosyngas by catalytic partial oxidation over a granular Ni-based catalyst. In addition, autothermal reforming of propane with water and normal air was also carried out. The investigations were performed in a partially adiabatic plasma-assisted (non-thermal) gliding arc (GlidArc) reactor at fixed pressure (1 bar) and electric power (0.3 kW). Detailed axial temperature distributions, product concentrations, reactant conversions, H 2 and CO yields, H 2/CO ratio and thermal efficiency, as a function of the cold and hot WCO flow rate, the water flow rate and the time on stream were studied. Propane and normal air were used as oxidizing components to maintain autothermal operation.

Bio-syngas production with low concentrations of CO 2 and CH 4 from microwave-induced pyrolysis of wet and dried sewage sludge

This paper assesses the feasibility of producing syngas from sewage sludge via two pyrolysis processes: microwave-induced pyrolysis (MWP) and conventional pyrolysis (CP). The changes in the composition of the produced gas as a function of the pyrolysis treatment and the initial moisture content of the sludge were evaluated. It was found that MWP produced a gas with a higher concentration of syngas than CP, reaching values of up to 94 vol%. Moreover, this gas showed a CO 2 and CH 4 concentration around 50% and 70%, respectively, lower than that obtained in the gas from CP. With respect to the effect of moisture on gas composition, this was more pronounced in CP than in MWP. Thus, the presence of moisture increases the concentration of H 2 and CO 2 and decreases that of CO, especially when CP was used. In order to elucidate the behaviour of CO 2 during the pyrolysis, the CO 2 gasification kinetics of the char obtained from the pyrolysis were investigated. It was established that in microwave heating the gasification reaction is much more favoured than in conventional heating. Therefore, the low concentration of CO 2 and the high concentration of CO in the microwave pyrolysis gas could be due to the self-gasification of the residue by the CO 2 produced during the devolatilization of the sewage sludge in the pyrolysis process.

Bio-syngas production from biomass catalytic gasification

A promising application for biomass is liquid fuel synthesis, such as methanol or dimethyl ether (DME). Previous studies have studied syngas production from biomass-derived char, oil and gas. This study intends to explore the technology of syngas production from direct biomass gasification, which may be more economically viable. The ratio of H 2 /CO is an important factor that affects the performance of this process. In this study, the characteristics of biomass gasification gas, such as H 2 /CO and tar yield, as well as its potential for liquid fuel synthesis is explored. A fluidized bed gasifier and a downstream fixed bed are employed as the reactors. Two kinds of catalysts: dolomite and nickel based catalyst are applied, and they are used in the fluidized bed and fixed bed, respectively. The gasifying agent used is an air-steam mixture. The main variables studied are temperature and weight hourly space velocity in the fixed bed reactor. Over the ranges of operating conditions examined, the maximum H 2 content reaches 52.47 vol%, while the ratio of H 2 /CO varies between 1.87 and 4.45. The results indicate that an appropriate temperature (750 °C for the current study) and more catalyst are favorable for getting a higher H 2 /CO ratio. Using a simple first order kinetic model for the overall tar removal reaction, the apparent activation energies and pre-exponential factors are obtained for nickel based catalysts. The results indicate that biomass gasification gas has great potential for liquid fuel synthesis after further processing.