Gas distributor and bed material effects in a cold flow model of a novel multi-stage biomass gasifier

Dhrioua, Maryem; Hassen, Walid; Kolsi, Lioua; Veerabathiran, Anbumalar; Alsagri, Ali Sulaiman; Borjini, Mohamed Naceur

doi:10.1016/j.biombioe.2019.05.001

Cited by 24 publications

(12 citation statements)

References 42 publications

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“…The gasifier studied in this paper is based on uncoupling different parts of the process into three linked zones: biomass pyrolysis; subsequently, combustion of volatiles; and finally, char reduction, which occurs in a bubbling fluidized bed. 33 Pyrolysis occurs mainly between 500 and 600 °C, producing char particles, pyrolysis gas, and tar. Noncondensable gas and tar are reacted with oxygen present in the combustion zone.…”

Section: Process Modelingmentioning

confidence: 99%

“…In the present study, a parametric study was performed to discuss the syngas composition and tar concentration, considering four compounds: toluene, phenol, benzene, and naphthalene. The main novelties of this work consist of refining previous studies, , allowing for enhanced predictions related to tar treatment modeling. In addition to the gas composition, the lower heating value and the cold gas efficiency were also investigated.…”

Section: Introductionmentioning

confidence: 99%

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Simulation of Biomass Air Gasification in a Bubbling Fluidized Bed Using Aspen Plus: A Comprehensive Model Including Tar Production

et al. 2022

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This work studied a multistage gasification system that is designed for producing a syngas with a low tar content. The proposed system is an atmospheric bubbling fluidized-bed gasifier and comprises mainly pyrolysis, combustion, and gasification zones. The numerical investigation is performed using Aspen Plus to study Prosopis Juliflora gasification. Chemical reactions as well as tar treatment in the process are investigated. Two different pyrolysis temperatures were considered: 500 and 600 °C, along with three different particle size ranges: 0.2–0.5, 0.5–1, and 1–2 mm. The effect of the air-to-biomass ratio, with values from 0.2 to 1.2, and the gasification reactor temperature, from 800 to 1000 °C, on the composition of product gas and tar species formation during the process (phenol, naphthalene, benzene, and toluene), its lower heating value (LHV), and cold gasification efficiency (CGE) were studied. Results showed that a pyrolysis temperature of 600 °C and a particle size range of 0.2–0.5 mm displayed less tar produced from both combustion and gasification zones and were associated with greater CO, H 2 , and CH 4 yields, compared to the other pyrolysis parameters tested. Increasing the gasification temperature led to increasing the CO, H 2 , and tar yields and decreasing the CH 4 yield and CGE. The maximum CGE combined with the minimum tar amount produced could be obtained with values of 800 °C and 1.2 for the gasification temperature and the air-to-biomass ratio, respectively. The numerical simulation results will be used to improve the performance of the proposed system.

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Section: Process Modelingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Simulation of Biomass Air Gasification in a Bubbling Fluidized Bed Using Aspen Plus: A Comprehensive Model Including Tar Production

et al. 2022

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“…As presented in Figure 1a, the considered system comprises three different stages: pyrolysis, combustion, and reduction. Details of the system are in the previous work of Dhrioua et al [20]. Initially, biomass is heated inside the pyrolysis reactor to yield char and pyrolytic gas.…”

Section: Concept Of the Multistage Gasifiermentioning

confidence: 99%

Simulation of Prosopis juliflora Air Gasification in Multistage Fluidized Process

et al. 2020

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A multistage atmospheric fluidized bed gasifier was developed using the Aspen Plus simulation process. The innovative gasification reactor aims to yield a high-quality product gas as it conducts pyrolysis, combustion, and reduction in different zones. In addition, it uses gas as a heat carrier and has a fluidized char bed in the reduction zone to enhance the in-situ tar reduction. In order to study the feasibility of the gasifier, an evaluation of the product gas and the process efficiency is required. The proposed model was based on the reaction rates and hydrodynamic parameters of the bubbling bed. Four different stages were initially considered in the simulation process: decomposition of the feed, partial volatile combustion, char reduction, and gas solid separation. The gasification reactor was operated over a temperature range of 800–1000 °C and an isothermal combustion reactor was operated at 1000 °C. In addition, the air to biomass mass ratio was varied from 0.2 to 0.5. It has been validated and displayed very good agreement with published data. Effects of gasification reactor temperature, air to biomass ratio, and gasifier dimensions on the composition of product gas were investigated Results showed that the principal component is CO and its concentration in the product gas increases with increase in gasifier temperature but decreases with increasing air to biomass ratio. The results also gave a relatively high value of the lowered gas caloric value and acceptable cold gas efficiency which help the sizing of gasifiers and the choice of optimal operating conditions.

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“…However, the wide variability of chemical and physical properties among different types of feedstocks determines a highly variable quality of the resulting syngas [12,13], that practically decrease the degree of suitability of its use in real production systems at a commercial level [14] or, anyhow, determines performances far lower than those achievable by exploiting fossil counterparts (on average, 30% less [15]).…”

Section: Introductionmentioning

confidence: 99%

The Effects of Syngas Composition on Engine Thermal Balance in a Biomass Powered CHP Unit: A 3D CFD Study

Costa,

Piazzullo

2024

Energies

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Syngas from biomass gasification represents an interesting alternative to traditional fuels in spark-ignition (SI) internal combustion engines (ICEs). The presence of inert species in the syngas (H2O, CO2, N2) reduces the amount of primary energy that can be exploited through combustion, but it can also have an insulating effect on the cylinder walls, increasing the average combustion temperature and reducing heat losses. A predictive numerical approach is here proposed to derive hints related to the possible optimization of the syngas-engine coupling and to balance at the best the opposite effects taking place during the energy conversion process. A three-dimensional (3D) computational fluid dynamics (CFD) model is developed, based on a detailed kinetic mechanism of combustion, to reproduce the combustion cycle of a cogenerative engine fueled by syngas deriving from the gasification of different feedstocks. Numerical results are validated with respect to experimental measurements made under real operation. Main findings reveal how heat transfer mainly occurs through the chamber and piston walls up to 50° after top dead center (ATDC), with the presence of inert gases (mostly N2) which decrease the syngas lower calorific value but have a beneficial insulating effect along the liner walls. However, the overall conversion efficiency of the biomass-to-ICE chain is mostly favored by high-quality syngas from biomasses with low-ashes content.

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Gas distributor and bed material effects in a cold flow model of a novel multi-stage biomass gasifier

Cited by 24 publications

References 42 publications

Simulation of Biomass Air Gasification in a Bubbling Fluidized Bed Using Aspen Plus: A Comprehensive Model Including Tar Production

Simulation of Biomass Air Gasification in a Bubbling Fluidized Bed Using Aspen Plus: A Comprehensive Model Including Tar Production

Simulation of Prosopis juliflora Air Gasification in Multistage Fluidized Process

The Effects of Syngas Composition on Engine Thermal Balance in a Biomass Powered CHP Unit: A 3D CFD Study

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