Influence of pressure on fluidized bed gasifier: Specific coal throughput and particle behavior

Li, Junguo; Liu, Wenhong; Liu, Zheyu; Zhan, Haijuan; Zhang, Yongqi; Hao, Zhenhua; Cheng, Zhonghu; Huang, Jiejie; Fang, Yitian

doi:10.1016/j.fuel.2018.02.005

Cited by 24 publications

(4 citation statements)

References 53 publications

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“…Another approach to assess the impact of pressure and composition of the gasification agent is based on thermodynamic equilibrium calculations and modelling. With equilibrium models, it was shown that rising pressure and temperature lead to lower H 2 and CO production, while yields of CO 2 and CH 4 increase [3,9,10]. Similarly, thermodynamic equilibrium approaches inform us that application of CO 2 for gasification, even more, strengthens the trend towards lower yields of H 2 and CO as a result of reversed water-gas shift and Boudouard reactions [11].…”

Section: Introductionmentioning

confidence: 99%

“…a linear or exponential character, depending on the feedstock and gasifier. For biomasses, the rise in the reactor output power can be approximated to change linearly with increasing pressure (up to 8 bar)[9,23,24]. In the constant heat input case, it is impossible to keep the relations between the amount of H 2 O/CO 2 fed into a reactor with a gasifying agent and the feedstock (carbon in fuel) constant.…”

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confidence: 99%

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Influence of pressure and CO2 in fluidized bed gasification of waste biomasses

Szul¹,

Głód²,

Iluk³

2020

Biomass Conv. Bioref.

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An autothermal fluidized bed reactor was used to research the influence of pressure (0–2 barg) on the gasification process of different types of biomasses. The tested feedstocks were bark and lignin while softwood pellet was used as a reference fuel. A mixture of O2/CO2/H2O was used as a gasification agent. The impact of the application of CO2 on the yield of H2 in product gas was determined. Resulting product gas was characterized by a high content of CO which makes its use for applications based on chemical synthesis very difficult without extensive upgrading or supply of H2 from external sources. CO2 proved to improve carbon conversion efficiency (CCE) of the gasification process and to be an option for its chemical sequestration (negative carbon footprint). A slight modification of conventional indices used to evaluate efficiencies of gasification systems (CCE and water/carbon ratio) was proposed, to take into account the impact of the additional source of carbon fed into the reactor. The increase of system pressure led to changes in the composition of the product gas in line with predictions of Le Chatelier’s principle. The influence was predominantly visible in higher yields of CH4 and lower overall production of product gas. For higher hydrocarbons (CxHy), the trend was unclear. A set of stable gasification parameters were achieved for each pressure level and a standard gasification temperature of 850 °C, except for gasification of lignin performed at 2 barg. A proposed explanation for the problem is the combined effect of the increasing concentration of ash in the fluidized bed and its low characteristic melting temperatures. Due to the obtained experimental findings, a new ash agglomeration index was formulated.

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Section: Introductionmentioning

confidence: 99%

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confidence: 99%

Influence of pressure and CO2 in fluidized bed gasification of waste biomasses

Szul¹,

Głód²,

Iluk³

2020

Biomass Conv. Bioref.

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“…The optical fiber probe (PV6D, Institute of Processing Engineering, Chinese Academy of Sciences, Beijing, China) was used to measure the instantaneous velocity. The probe with two cross‐sectional areas of 1 × 1 mm 2 consists of five bunches 200‐µm quartz fibers for light‐emitting and light‐receiving 21, 22. The larger particles of silica gel ( d p = 10 µm, St = 0.05–0.72) are used as tracer particles to measure the instantaneous gas velocity.…”

Section: Experimental Setup and Methodsmentioning

confidence: 99%

Evolution and Dynamics of the Coherent Vortices in Contraction and Premix Coaxial Jets

Hao

et al. 2022

Chem Eng & Technol

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Contraction and premix coaxial jets are commonly employed in gasification and combustion systems. Understanding the spatial development of coherent structures is a prerequisite to improve the mixing and stability characteristics. The evolution and dynamics of coherent vortices under the contraction and premix coaxial jets are visualized and discussed using flow visualization technology. The contraction configuration increases the instability of the outer shear layer corresponding to an organized rolling up of the outer vortex rings. In the premixed configuration, the earlier interaction between the inner and outer shear layers induces the precocious development of the inner Kelvin-Helmholtz (K-H) vortices. Two empirical equations are proposed to predict the transition length towards a fully turbulent flow.

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“…From the standpoint of thermodynamic equilibrium calculations and modelling, it is known that increasing the pressure and temperature of the gasification process leads towards lower production of H 2 and CO, while larger amounts of CO 2 and CH 4 are produced. This, unfortunately, opposes the common goals of BtX technologies and thus induces the need for additional gas upgrading and conversion processes [5,16,17]. At the same time, through the thermodynamic equilibrium calculations we know that using CO 2 for gasification further lowers the yields of H 2 at the expense of increased production of CO.…”

Section: Introductionmentioning

confidence: 99%

Use of CO2 in Pressurized, Fluidized Bed Gasification of Waste Biomasses

2022

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This research discusses the results of experiments performed on a large-scale gasification installation to determine the influence of total system pressure and partial pressure of CO2 on the efficiency of conversion and the quality of the produced gas. The three tested feedstocks were bark, lignin and a blend of bark and wheat straw, while softwood pellet (SWP) was used as a reference fuel. A mixture of O2/CO2/H2O was used as a gasification agent. The tests were devised to validate the previously proposed process parameters, verify whether similar ash agglomeration problems would occur and compare the thermal behaviour of the feedstocks converted in close-to-industrial process conditions. An understanding of the effect of using CO2 for gasification was further deepened, especially regarding its influence on the yield of H2 and temperature profiles of the fluidized bed. The influence of gasification pressure was predominantly visible in higher yields of all hydrocarbons (including CH4) and lower overall production of producer gas. At the process development unit (PDU), all tested feedstocks were converted at similar process conditions and no signs of potential bed agglomeration could be noticed. This opposes the findings observed in smaller-scale bubbling fluidized bed (BFB) tests. The discussion behind these discrepancies is also presented.

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Influence of pressure on fluidized bed gasifier: Specific coal throughput and particle behavior

Cited by 24 publications

References 53 publications

Influence of pressure and CO2 in fluidized bed gasification of waste biomasses

Influence of pressure and CO2 in fluidized bed gasification of waste biomasses

Evolution and Dynamics of the Coherent Vortices in Contraction and Premix Coaxial Jets

Use of CO2 in Pressurized, Fluidized Bed Gasification of Waste Biomasses

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