Production, characterization and reactivity studies of chars produced by the isothermal pyrolysis of flax straw

Tushar, Mohammad Shahed Hasan Khan; Mahinpey, Nader; Khan, Ataullah; Ibrahim, Hussameldin; Kumar, Prashant; Idem, Raphael

doi:10.1016/j.biombioe.2011.12.027

Cited by 66 publications

(18 citation statements)

References 40 publications

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“…For its part, increasing pyrolysis peak temperature did not result in a decrease in reactivity; on the contrary, hightemperature chars exhibited a slightly higher reactivity, especially for those produced at the lowest heating rate. This finding seems to be in disagreement with previous studies [8,57], in which a decrease in reactivity towards oxygen with peak temperature was reported for chars derived from lignocellulosic precursors (wood spruce and flax straw). In these studies, it was suggested that higher pyrolysis temperatures led to more ordered structures and a higher formation of secondary char (which can cause clogging of pores).…”

Section: Rdf-derived Char Reactivity In Aircontrasting

confidence: 83%

Pyrolysis and char reactivity of a poor-quality refuse-derived fuel (RDF) from municipal solid waste

Manyà

García-Ceballos

Azuara

et al. 2015

Fuel Processing Technology

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• Increasing both heating rate and peak temperature led to more reactive RDF chars. 2• The co-pyrolysis of the RDF and two-phase olive mill waste was also investigated. 3• The reactivity of resulting TPOMW chars increased in the presence of RDF. 4• The carbonization efficiency of TPOMW was improved in the presence of RDF. 5• Results motivate further studies on the use of this RDF as pyrolysis additive.The present study focuses on analyzing the pyrolysis and combustion behaviors of a refuse-8 derived fuel (RDF), which is generated in a MSW treatment plant located in Zaragoza (Spain). 9Pyrolysis experiments were carried out in a TGA apparatus and a fixed-bed reactor at different 10 peak temperatures (400 and 600 °C) and heating rates (5 and 40 °C min -1 ). The reactivity towards 11 oxygen of produced chars was also measured in the same TGA device at a heating rate of 10 °C 12 min -1 and a final temperature of 800 °C. Pyrolysis results were significantly affected by peak 13 temperature and heating rate. The found effect of peak temperature on char and fixed-carbon 14 yields as well as on measured properties (H:C and O:C ratios, BET surface area and average pore 15 diameter) was in agreement with previous studies. However, the effect of heating rate, especially 16 on the release rate of volatiles, could be explained by a change in the pyrolysis reactions scheme. 17The RDF-derived chars obtained at the highest heating rate showed a higher reactivity in air. In 18 addition, an increase in peak temperature also led to a higher reactivity. This result can indicate 19that the carbon present in the RDF-derived char is dispersed within an ash matrix containing a 20 high number of active sites, the distribution of which could be improved when heating rate (and, 21 to a lesser extent, peak temperature) is increased. The addition of 10 wt. % RDF to two-phase 22 olive mill waste prior to slow pyrolysis led to an apparent increase in the carbonization efficiency 23as well as to an enhancement of the resultant char's reactivity in air.

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Section: Rdf-derived Char Reactivity In Aircontrasting

confidence: 83%

Pyrolysis and char reactivity of a poor-quality refuse-derived fuel (RDF) from municipal solid waste

Manyà

García-Ceballos

Azuara

et al. 2015

Fuel Processing Technology

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“…Figure 3 and Figure 4 also show a different effect of heating rate in olive solids and in eucalyptus solids. It has been reported that the longer the char residence time, the greater its surface area [31,32]. This was not the case in this study, which may be due to the fact that 20 °C·min −1 is a low enough heating rate under which no further increase in surface area is produced.…”

Section: Resultscontrasting

confidence: 53%

Biomass Pyrolysis Solids as Reducing Agents: Comparison with Commercial Reducing Agents

Adrados

Marco

López-Urionabarrenechea

et al. 2015

Materials

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Biomass is one of the most suitable options to be used as renewable energy source due to its extensive availability and its contribution to reduce greenhouse gas emissions. Pyrolysis of lignocellulosic biomass under appropriate conditions (slow heating rate and high temperatures) can produce a quality solid product, which could be applicable to several metallurgical processes as reducing agent (biocoke or bioreducer). Two woody biomass samples (olives and eucalyptus) were pyrolyzed to produce biocoke. These biocokes were characterized by means of proximate and ultimate analysis, real density, specific surface area, and porosity and were compared with three commercial reducing agents. Finally, reactivity tests were performed both with the biocokes and with the commercial reducing agents. Bioreducers have lower ash and sulfur contents than commercial reducers, higher surface area and porosity, and consequently, much higher reactivity. Bioreducers are not appropriate to be used as top burden in blast furnaces, but they can be used as fuel and reducing agent either tuyére injected at the lower part of the blast furnace or in non-ferrous metallurgical processes where no mechanical strength is needed as, for example, in rotary kilns.

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“…The effect of heating rates and catalyst are investigated in this study, although other factors, such as temperature, also play an important role 31,32,17 . The char/coke 20 yields are significantly decreasing when fast heating rates are applied to the pyrolysis compared with slow heating rates.…”

Section: Resultsmentioning

confidence: 99%

“…However, most of the 35 published work focuses on thermal chars, [30][31][32] leading to a lack of understanding of the mechanisms and effects of char and coke formation when catalyst is introduced in the pyrolysis. This work focuses on studying catalyst deactivation and the effectiveness of model compounds, in particular glucose and cellulose, as 40 compared to pine from the perspective of comparing their pyrolysis char and coke characteristics.…”

Section: Introductionmentioning

confidence: 99%

Characteristics and origin of char and coke from fast and slow, catalytic and thermal pyrolysis of biomass and relevant model compounds

2013

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Char and coke from biomass catalytic pyrolysis have different origins. They cannot be lumped as one since they occupy different locations on the catalyst surface and, thus, contribute differently to catalyst deactivation. In this study, catalyst (ZSM-5) deactivation in the perspective of comparison of char and coke from pyrolysis of different biomass types is investigated. Pine sawdust, glucose, and cellulose are used as feedstocks in the pyrolysis experiments. Biomass char and coke samples produced via slow and fast, thermal and catalytic pyrolysis are characterized with respect to their overall content, oxidation reactivity, catalyst surface area, pore size distribution changes, bonding groups and their effect on catalyst performance. In particular, it is shown that char forms as an external layer on the catalyst surface and in its macropores, whereas coke forms inside the zeolite micropores via hydrogen transfer and addition reactions. The catalyst effect on glucose and pine slow catalytic pyrolysis is minor compared with that on cellulose slow catalytic pyrolysis, due to macropore blocking by char formation. In fast catalytic pyrolysis, catalyst deactivation is mainly attributed to micropore blocking by coke formation. Char and coke are shown to coexist on the catalyst surface after fast catalytic experiments, with the char content after glucose fast catalytic pyrolysis being 30 wt% of the total solid residue. The origins of char and coke in the cellulose, hemicellulose and lignin components of pine are identified and mechanisms for their formation are proposed.

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Production, characterization and reactivity studies of chars produced by the isothermal pyrolysis of flax straw

Cited by 66 publications

References 40 publications

Pyrolysis and char reactivity of a poor-quality refuse-derived fuel (RDF) from municipal solid waste

Pyrolysis and char reactivity of a poor-quality refuse-derived fuel (RDF) from municipal solid waste

Biomass Pyrolysis Solids as Reducing Agents: Comparison with Commercial Reducing Agents

Characteristics and origin of char and coke from fast and slow, catalytic and thermal pyrolysis of biomass and relevant model compounds

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