Combustion Properties of Biomass Flash Pyrolysis Oils: Final Project Report

Shaddix, Christopher R.; Hardesty, D.R.

doi:10.2172/5983

Cited by 60 publications

(114 citation statements)

References 37 publications

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“…Video recordings of droplet behaviour showed similar phenomena to those observed by others [1][2][3][4], and Figs. 2 -4 summarize these observations as time lines.…”

Section: Droplet Historysupporting

confidence: 87%

“…A nitrogen atmosphere was used in the furnace to suppress combustion and ensure pure evaporation, thus more nearly simulating conditions in spray combustion, where droplets evaporate in a vapour cloud rather than burning individually. Other experiments conducted on biomass pyrolysis oils to date have examined single droplet combustion rather than evaporation [1][2][3][4], and hence are not directly comparable with either these experiments or the results of the present model.…”

Section: Methodsmentioning

confidence: 59%

“…After an initial heating period in which no significant change was observed, the droplet underwent vigorous bubbling and disruption, swelling to about twice its original diameter and collapsing again around 4-5 times per second. (Other writers have referred to "microexplosions" [1][2][3][4], but the bubbling in the present experiments was not violent enough to warrant this name, and did not discharge material from the droplet.) With time the liquid became more viscous and the droplet surface appeared to "skin over"; this progressively restricted bubbling, leading to a quieter period in which the droplet no longer bubbled but still moved around erratically on the fibre.…”

Section: Droplet Historymentioning

confidence: 55%

“…Typically the initial liquid heating period is followed by bubbling and/or "micro-explosions", after which the heavy non-volatile residue remaining pyrolyzes to a highly porous, irregularly-shaped char particle or "cenosphere" [1][2][3][4].…”

Section: Introductionmentioning

confidence: 99%

“…The chemical composition may change over time owing to "aging", in which light components are polymerized [18,26,27], and phase separation is also possible [6,7]. Studies of the combustion behaviour of single droplets have been performed 5 on free-falling droplets in drop tube furnaces [1][2][3][4] as well on suspended droplets [4], and have established the sequence of combustion events described earlier. Combustion tests have also been performed in gas turbine combustors and Diesel engines [22,28].…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

A model for the evaporation of biomass pyrolysis oil droplets

Hallett¹,

Clark²

2006

Fuel

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This paper presents a numerical model for the evaporation and pyrolysis of a single droplet of pyrolysis oil derived from biomass. Continuous thermodynamics theory for multicomponent droplet evaporation is used, with the fuel being represented by four fractions: organic acids, aldehydes/ketones, water, and pyrolytic lignin, each of which is described by a separate distribution function. Pyrolysis of the lignin fraction is included, and detailed properties for all fractions are presented. The model is compared with the results of suspended droplet experiments, and is shown to give good predictions of the times of the major events in the lifetime of a droplet.

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“…Video recordings of droplet behaviour showed similar phenomena to those observed by others [1][2][3][4], and Figs. 2 -4 summarize these observations as time lines.…”

Section: Droplet Historysupporting

confidence: 87%

Section: Methodsmentioning

confidence: 59%

Section: Droplet Historymentioning

confidence: 55%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

A model for the evaporation of biomass pyrolysis oil droplets

Hallett¹,

Clark²

2006

Fuel

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Spontaneous Aerosol Ejection: Origin of Inorganic Particles in Biomass Pyrolysis

et al. 2016

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At high thermal flux and temperatures of approximately 500 °C, lignocellulosic biomass transforms to a reactive liquid intermediate before evaporating to condensable bio-oil for downstream upgrading to renewable fuels and chemicals. However, the existence of a fraction of nonvolatile compounds in condensed bio-oil diminishes the product quality and, in the case of inorganic materials, catalyzes undesirable aging reactions within bio-oil. In this study, ablative pyrolysis of crystalline cellulose was evaluated, with and without doped calcium, for the generation of inorganic-transporting aerosols by reactive boiling ejection from liquid intermediate cellulose. Aerosols were characterized by laser diffraction light scattering, inductively coupled plasma spectroscopy, and high-speed photography. Pyrolysis product fractionation revealed that approximately 3 % of the initial feed (both organic and inorganic) was transported to the gas phase as aerosols. Large bubble-to-aerosol size ratios and visualization of significant late-time ejections in the pyrolyzing cellulose suggest the formation of film bubbles in addition to the previously discovered jet formation mechanism.

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Fast pyrolysis of coffee ground in a tilted‐slide reactor and characteristics of biocrude oil

Choi

Kim

et al. 2017

Env Prog and Sustain Energy

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Coffee grounds are considered to be a promising biomass resource due to the growth of coffee consumption and their high calorific value. In this study, we produced biocrude oil from coffee grounds in a tilted‐slide reactor, which has been previously used for the fast pyrolysis of woody biomass. Various pyrolysis temperatures were tested and the maximum biocrude oil yield was 59% at the pyrolysis temperature of 550°C with a feeding rate of coffee grounds at 17.7 kg/h. In a multistage condenser, the biocrude oil yields and properties were different in each condenser stage. The higher heating value of the biocrude oil from the primary condenser was 7,157 kcal/kg, which was about 60% higher than that from woody biomass. A phase separation was observed when the biocrude oil was stored at the atmospheric condition, and the biocrude oil viscosity became quite larger than that from woody biomass, which could even impede its flow. The viscosity decreased with increasing temperature and was more sensitive to temperature variations at lower temperatures. Mixing of ethanol also significantly improved viscosity characteristics. © 2017 American Institute of Chemical Engineers Environ Prog, 36: 655–661, 2017

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Combustion Properties of Biomass Flash Pyrolysis Oils: Final Project Report

Cited by 60 publications

References 37 publications

A model for the evaporation of biomass pyrolysis oil droplets

A model for the evaporation of biomass pyrolysis oil droplets

Spontaneous Aerosol Ejection: Origin of Inorganic Particles in Biomass Pyrolysis

Fast pyrolysis of coffee ground in a tilted‐slide reactor and characteristics of biocrude oil

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