Quality of gas produced from wheat straw in a dual-distributor type fluidized bed gasifier

The gasification of lignite could be a promising sustainable alternative to combustion, because it causes reduced emissions and allows the production of syngas, which is a versatile gaseous fuel that can be used for cogeneration, Fischer-Tropsch synthesis, or the synthesis of other bio-fuels, such as methanol. For the safe and smooth exploitation of syngas, it is fundamental to have a high quality gas, with a high content of H2 and CO and minimum content of pollutants, such as particulate and tars. In this work, experimental tests on lignite gasification are carried out in a bench-scale fluidized-bed reactor with olivine as bed material, chosen for its catalytic properties that can enhance tar reduction. Some operating parameters were changed throughout the tests, in order to study their influence on the quality of the syngas produced, and pressure fluctuation signals were acquired to evaluate the fluidization quality and diagnose correlated sintering or the agglomeration of bed particles. The effect of temperature and small air injections in the freeboard were investigated and evaluated in terms of the conversion efficiencies, gas composition, and tar produced.

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Effects of Fluidization Velocity and Equivalence Ratio on the Energy and Exergy of the Syngas Produced from Wheat Straw in A Dual-distributor Type Fluidized Bed Gasifier

Advances in Research ◽

10.9734/air/2015/7751 ◽

2015 ◽

Vol 3 (1) ◽

pp. 20-35 ◽

Cited By ~ 2

Author(s):

Yaning Zhang ◽

Abdel Ghaly ◽

Ali Ergudenler ◽

Bingxi Li

Keyword(s):

Wheat Straw ◽

Fluidized Bed ◽

Equivalence Ratio ◽

Fluidization Velocity ◽

Energy And Exergy ◽

Fluidized Bed Gasifier

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Determination of Energy and Exergy of Syngas Produced from Air-steam Gasification of Wheat Straw in a Dual Distributer Fluidized Bed Gasifier

Journal of Energy Research and Reviews ◽

10.9734/jenrr/2019/v3i130089 ◽

2019 ◽

pp. 1-24

Author(s):

Yaning Zhang ◽

Abdel Ghaly ◽

Samy S. Sadaka ◽

Bingxi Li

Keyword(s):

Total Energy ◽

Wheat Straw ◽

Fluidized Bed ◽

Steam Gasification ◽

Operating Conditions ◽

Steam Flow ◽

Flow Rates ◽

Energy And Exergy ◽

Fluidized Bed Gasifier

The energy and exergy of syngas produced from air-steam gasification of wheat straw in a dual-distributor fluidized bed gasifier under different operating conditions were evaluated. Three fluidization velocities (0.35, 0.40 and 0.45 m/s), 3 steam flow rates (0.20, 0.25 and 0.30 kg/min) and 3 biomass: steam ratios (3.00, 4.00 and 5.00 kg/kg) were investigated. The energy values of CO, H2, N2, CO2, CH4, C2H4 and C2H6 varied within the ranges of 1627.09-4646.60, 1543.30-2896.11, 274.75-1742.86, 82.03-574.24, 3225.39-4931.40, 1493.35-3777.44 and 892.74-2319.72 kJ/kg fuel, respectively. The overall energy distribution was (CH4 & CO & C2H4 & H2)>C2H6>(N2 & CO2). The results showed that when the fluidization velocity (FV) was increased from 0.35 m/s to 0.45 m/s (28.57%), the total energy of syngas increased by 1.16-28.59% depending on the steam flow rate (SFR} and biomass: steam ratio (B:S) used. Increasing the SFR from 0.20 kg/min to 0.30 kg/min (50.00%) decreased the total energy of syngas by 27.23-62.35% depending on the FV and B:S used. Increasing the B:S from 3.00 kg/kg to 5.00 kg/kg (66.67%) decreased the total energy of syngas by 11.86-37.33% depending on the FV and SFR used. The exergy values of CO, H2, N2, CO2, CH4, C2H4 and C2H6 were in the ranges of 1486.70-4224.40, 1183.82-2209.00, 60.26-677.26, 54.02-452.97, 2913.74-4448.38, 1404.76-3541.76 and 833.00-2156.42 kJ/kg fuel, respectively. The overall exergy distribution was (CH4 & CO)>(C2H4 & H2 & C2H6)>(N2 &CO2). When the FV was increased from 0.35 to 0.45 m/s(28.57%), the total exergy of syngas increased by 1.45-26.93% depending on the SFR and B:S used. Increasing the SFR from 0.20 kg/min to 0.30 kg/min (50.00%) decreased the total exergy of syngas by 26.78-63.26% depending on the FV and B:S used. Increasing the B:S from 3.00 kg/kg to 5.00 kg/kg (66.67%) decreased the total exergy of syngas by 10.32-36.07% depending on the FV and SFR used. The effect of SFR on the total energy and total exergy of syngas was the highest, followed by B:S and FV. The highest energy (20004.54 kJ/kg fuel) and exergy (16886.06 kJ/kg fuel) of syngas were obtained at the FV of 0.45 m/s, the SFR of 0.20 kg/min and the B:S of 3.00 kg/kg.

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The Analysis of Influence of the Gangue in the Coal as Fired on the Coal Conveying System and the Boiler Operation of the Circulating Fluidized Bed Unit

E3S Web of Conferences ◽

10.1051/e3sconf/201911802011 ◽

2019 ◽

Vol 118 ◽

pp. 02011

Author(s):

Su Pan ◽

Yu Pengfeng ◽

Linbo Liu ◽

Han Jing ◽

Xiao Shen

Keyword(s):

Fluidized Bed ◽

Circulating Fluidized Bed ◽

Storage Conditions ◽

Coal Gangue ◽

Quality Data ◽

Stable Operation ◽

Coal Quality ◽

Boiler Operation ◽

Conveying System

The coal as fired, with unidentified characteristics of the coal gangue, was burned on a 300MW circulating fluidized bed unit. The equipment of the coal conveying system was damaged and the boiler operation was unstable. In response to the problems, the coal quality data and storage conditions of the coal were examined and the site was spot-checked to evaluate the coal quality characteristics. At the same time, the typical representative parameters of the coal handling system and boiler operation were selected. According to the analysis of coal quality and coal storage, the coal quality fluctuates greatly and the uniformity of particle size distribution is poor. There is actually the coal gangue with hard texture and hard to grind in the coal pile. The coal gangue will have adverse effects on the fine screening machine, fine crusher and other equipment. After burned this type of coal, the fluidized quality of the boiler bed is degraded to make an impact on the safe and stable operation of the boiler. It is recommended that the coal should be screened and then burned into the furnace to ensure safe and stable operation of the boiler.

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