Some aspects of fluidized bed combustion of paddy husk

Bhattacharya, S.C.; Shah, N.; Alikhani, Z.

doi:10.1016/0306-2619(84)90005-9

Cited by 33 publications

(6 citation statements)

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“…Slagging or fouling, in association with rice husk combustion, does not seem to have been reported in any available literature. None of the laboratory studies or pilot-scale studies presented in the excellent overview of rice husk firing by Natarajan et al or other research groups − have reported any slagging and fouling problems. One recent laboratory study of FBC firing of rice husk briefly mentions that no ash-related problems were observed during the tests …”

Section: Introductionmentioning

confidence: 94%

The Fouling Behavior of Rice Husk Ash in Fluidized-Bed Combustion. 2. Pilot-Scale and Full-Scale Measurements

et al. 2005

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This paper is the second in a series of two on the slagging and fouling behavior of rice husk when fired alone or in combination with other fuels in a fluidized-bed boiler. The first paper involved the fuel properties of rice husk, as investigated by a variety of laboratory methods. In this second paper, we report the results of fireside fouling measurements when burning rice husk alone and together with eucalyptus bark in various ratios. This study is based on short-term (3−10 h) deposit samples taken with air-cooled deposit probes in the superheater region of a large-scale (157 MWth) bubbling fluidized-bed (BFB) boiler burning rice husk and eucalyptus bark. Using an entrained-flow type of pilot furnace, we further made more, systematic measurements of the influence of the fuel mixture ratio on the fouling tendency of the fly ash formed. Burning of rice husk alone did not result in any detectable fouling, neither in the pilot furnace nor on the deposit probes in the superheater area of the fluidized-bed boiler. After deposit samplings with durations of up to 10 h during 100% rice husk firing, the deposit sampling probe had not collected more than ∼95 mg of deposit material. The combustion of eucalyptus bark alone caused significant fouling. Here, the corresponding amount of deposit was ∼90 mg after 10 h of sampling. The fouling tendency of mixtures of rice husk and bark showed a nonlinear dependence on the fuel mixture ratio. The results suggest that the rice husk ash acted as an erosive, cleaning agent in the fly ash mix.

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Section: Introductionmentioning

confidence: 94%

The Fouling Behavior of Rice Husk Ash in Fluidized-Bed Combustion. 2. Pilot-Scale and Full-Scale Measurements

et al. 2005

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“…Furthermore, uncontrolled open burning of these materials produces crystalline ash with high emissions [59], which is well recognized as a lung carcinogen as well as the health risk from silicosis caused by silica deposition in the lung tissue [60,61]. To overcome these issues, researchers have been investigated feasible, economical, and environmentally friendly strategies to convert RH and RS into pure biogenic silica via combustion based on various scientific publications [53,54,[62][63][64][65][66][67][68][69][70][71][72][73] and patents [74].…”

Section: Introductionmentioning

confidence: 99%

Generation of High Quality Biogenic Silica by Combustion of Rice Husk and Rice Straw Combined with Pre- and Post-Treatment Strategies—A Review

et al. 2019

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Utilization of biomass either as a renewable energy source or for the generation of biogenic materials has received considerable interest during the past years. In the case of rice husk (RH) and rice straw (RS) with high silica contents in the fuel ash, these approaches can be combined to produce high-grade biogenic silica with purities >98 wt % from combustion residues. The overall process can be considered nearly neutral in terms of CO2 emission and global warming, but it can also address disposal challenges of rice husk and rice straw. For the resulting biogenic silica, several advanced application opportunities exist, e.g., as adsorbents, catalysts, drug delivery systems, etc. This article provides a comprehensive literature review on rice husk and rice straw combustion as well as applied strategies for raw material pre-treatment and/or post-treatment of resulting ashes to obtain high quality biogenic silica. Purity of up to 97.2 wt % SiO2 can be reached by combustion of untreated material. With appropriate fuel pre-treatment and ash post-treatment, biogenic silica with purity up to 99.7 wt % can be achieved. Studies were performed almost exclusively at a laboratory scale.

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“…Singh et al (1980) reported that the maximum combustion intensity of rice husk in a grate-type furnace is about 70 kg/h-m 2 . In a fluidized bed reactor Bhattacharya et al (1983) achieved a combustion intensity of 530 kg/h-m 2 with rice husk fuel. To achieve higher combustion efficiency, the primary air is passed through the distributor plate at a rate slightly higher than that required for char combustion and the remaining excess air is supplied as secondary air at the entrance of the enlarged section of the freeboard.…”

Section: Effect Of Feed Rate On the Temperature Profile In The Combusmentioning

confidence: 99%

“…It has been suggested that satisfactory combustion of the bagasse, sawdust and the rice husks could be achieved with under-bed feeding only. Bhattacharya et al (1983) reported the combustion efficiency of rice husk in the range of 81 to 98%. It has also been suggested that higher combustion efficiencies could be achieved by providing an enlarged freeboard, which effectively reduces the flue gas velocity.…”

Section: Introductionmentioning

confidence: 99%

Effect of secondary air injection on the combustion efficiency of sawdust in a fluidized bed combustor

Rao

Reddy

2008

Braz. J. Chem. Eng.

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Agricultural wastes like bagasse, paddy husks, sawdust and groundnut shells can be effectively used as fuels for fluidized bed combustion; otherwise these biomass fuels are difficult to handle due to high moisture and fines content. In the present work the possibility of using sawdust in the fluidized bed combustor, related combustion efficiencies and problems encountered in the combustion process are discussed. The temperature profiles for sawdust with an increase in fluidizing velocity along the vertical height above the distributor plate indicate that considerable burning of fuel particles is taking place in the freeboard zone rather than complete burning within the bed. Therefore, an enlarged disengagement section is provided to improve the combustion of fines. The temperature profiles along the bed height are observed at different feed rates. The feed rate of sawdust corresponding to the maximum possible temperature was observed to be 10.2 kg/h. It is observed that 50-60% excess air is optimal for reducing carbon loss during the burning of sawdust. The maximum possible combustion efficiency with sawdust is 99.2% and is observed with 65% excess air

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Some aspects of fluidized bed combustion of paddy husk

Cited by 33 publications

References 0 publications

The Fouling Behavior of Rice Husk Ash in Fluidized-Bed Combustion. 2. Pilot-Scale and Full-Scale Measurements

The Fouling Behavior of Rice Husk Ash in Fluidized-Bed Combustion. 2. Pilot-Scale and Full-Scale Measurements

Generation of High Quality Biogenic Silica by Combustion of Rice Husk and Rice Straw Combined with Pre- and Post-Treatment Strategies—A Review

Effect of secondary air injection on the combustion efficiency of sawdust in a fluidized bed combustor

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