Thermochemical and structural changes in Jatropha curcas seed cake during torrefaction for its use as coal co-firing feedstock

Madanayake, Buddhike Neminda; Gan, Suyin; Eastwick, Carol; Ng, Hoon Kiat

doi:10.1016/j.energy.2016.01.097

Cited by 17 publications

(3 citation statements)

References 52 publications

(65 reference statements)

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“…The heating of the reactor began 5 min after gas was introduced into the reactor. CO 2 was cut off when the temperature inside the reactor had fallen below 100 • C for safety [21]. A sample crucible could contain between 250 and 300 g of SS for single variant biochar generation.…”

Section: Biochar Production From Sewage Sludgementioning

confidence: 99%

Is Biochar from the Torrefaction of Sewage Sludge Hazardous Waste?

et al. 2020

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Improved technologies are needed for sustainable management of sewage sludge (SS). The torrefaction (also known as biomass “roasting”) is considered a pretreatment of SS before use in agriculture. However, it is not known whether the torrefaction has the potential to decrease heavy metals’ (HMs) leachability and the SS toxicity. Thus, the aim of the study was to evaluate the influences of the SS torrefaction parameters (temperature and process time) on HM contents in biochar, HM leachability, and biochar toxicity, and compare them with raw SS. The experiments were designed in 18 combinations (six temperatures, 200, 220, 240, 260, 280, and 300 °C; and three process times—20, 40, 60 min). Standard tests were used to determine HMs content, leachability, and toxicity. Results indicated that the torrefaction did not increase (p < 0.05) the HM content in comparison to the raw SS. The leachability of Zn, Ni, Cu, Cr, and Mn from SS biochars was similar to raw SS. However, the degree of leachability varied significantly (p < 0.05) from as low as 0.1% for Cu to high as 16.7% for Cd. The leachability of Cd (<16.7%) and Pb (<11.9%) from biochars was higher than from raw SS (<6.1% and <2.4%, respectively). The leachability of Cd from SS biochar, in five torrefaction combinations, was higher than the threshold value for hazardous waste. It is recommended that site-specific decisions are made for torrefaction of SS with respect to its HM content, as the resulting biochar could be considered as hazardous waste, depending on the feedstock. Moreover, the biochar produced under the whole range of temperatures during 20 min retention time significantly (p < 0.05) increased the Daphnia magna Straus mobility inhibition by up to 100% in comparison to the biochar obtained during 40 and 60 min torrefaction. Taking into account the increased leachability of specific HMs and D. magna Straus mobility inhibition, biochar should be considered a potentially hazardous material. Future research should focus on biochar dosage as a fertilizer in relation to its toxicity. Additional research is warranted to focus on the optimization of SS torrefaction process parameters affecting the toxicity.

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Section: Biochar Production From Sewage Sludgementioning

confidence: 99%

Is Biochar from the Torrefaction of Sewage Sludge Hazardous Waste?

et al. 2020

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“…The heating of the reactor was commenced 5 minutes after gas introduction into the device began. Carbon dioxide was cut off when the temperature inside the reactor during the cooling phase reached 100°C (Madanayake et al, 2016).…”

Section: Carbonized Refuse Derived Fuel Production Methodsmentioning

confidence: 99%

Kinetic Parameters of Torrefaction Process of Alternative Fuel Produced From Municipal Solid Waste and Characteristic of Carbonized Refuse Derived Fuel

Stępień

Białowiec²

2018

Detritus

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Torrefaction is next to drying, pelletizing and briquetting one of the methods for pre-treatment of fuels for later use for energy purposes. Torrefaction is a thermo-chemical process, carried out in the temperature range from 200 to 300°C, under atmospheric pressure and inert gas environment. The study involved a refuse derived fuel (RDF) produced from municipal solid waste in a mechanical-biological plant. The aim of this work was to determine the kinetic parameters of the torrefaction process of RDF and to examine the effect of temperature and the residence time on fuel properties of biochar. Torrefaction process was carried out in the temperature range from 200 to 300°C with the temperature interval of 20°C. The residence was respectively 20, 40 and 60 minutes for each temperature. RDF and the resulting carbonized refuse derived fuel (CRDF) have been subjected to the following analysis: moisture content, organic matter, combustible and volatile content, ash content, and higher heating value. The determined activation energy of RDF torrefaction was 3.71 kJ•mol -1 . The thermogravimetric analysis indicated that during torrefaction, mostly lingo-cellulosic, and hemi-cellulosic biomass present in RDF decomposes during torrefaction. Studies have shown the influence of residence time and temperature on fuel properties of the obtained CRDF. The highest heating value of the CRDF was obtained for the temperature of 260°C, and residence time 20 minutes.

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“…These properties can be improved for combustion with coal through mild pyrolysis, called torrefaction, in which raw biomass is heated in an inert atmosphere to temperatures between 200 and 300 C. Torrefaction has been shown to significantly improve biomass properties, making biomass more suitable for co-firing applications [14,15]. Specifically, torrefaction reduces the oxygen and hydrogen contents of biomass, thereby concentrating the carbon content and increasing the heating value [16]. The hemicellulose portion of biomass is substantially degraded and the biomass is rendered hydrophobic during torrefaction due to the loss of ÀOH functional groups, which improves the storability of the biomass [17].…”

Section: Introductionmentioning

confidence: 99%

Torrefaction of Healthy and Beetle Kill Pine and Co-Combustion With Sub-Bituminous Coal

Howell

Beagle

Belmont

2017

Journal of Energy Resources Technology

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Combustion of biomass and co-combustion with fossil fuels are viable means of reducing emissions in electricity generation, and local biomass resources are appealing to minimize life cycle emissions. In the Rocky Mountain Region of the U.S., a bark beetle epidemic is causing widespread forest death and associated safety hazards. This biomass has potential to be a feedstock resource, thereby achieving dual goals of improving forest health while supplying biomass for uses such as co-firing with coal in power plants. In this study, combustion and co-combustion of healthy pine (HP) and beetle kill pine (BK) with coal were conducted to assess the interchangeability of these feedstocks in raw and torrefied forms. HP and BK pine were torrefied at 200, 250, and 300 C to increase energy density and improve grindability, both of which aid in seamless integration into power plants. Grindability was assessed for both feedstocks at each torrefaction condition. The raw feedstocks were pyrolyzed to assess their relative compositions. Raw and torrefied feedstocks were then combusted alone and co-combusted with sub-bituminous Powder River Basin coal using thermogravimetric analysis (TGA). Modulated TGA was used to derive kinetic parameters of coal, raw and torrefied biomass, and coal-biomass blends. Results show increased grindability and pyrolysis mass loss of BK as compared to HP, which are attributed to the degraded state of the wood. Combustion and cocombustion show favorable interchangeability of the HP and BK, and additive behavior when co-combusted with coal.

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Thermochemical and structural changes in Jatropha curcas seed cake during torrefaction for its use as coal co-firing feedstock

Cited by 17 publications

References 52 publications

Is Biochar from the Torrefaction of Sewage Sludge Hazardous Waste?

Is Biochar from the Torrefaction of Sewage Sludge Hazardous Waste?

Kinetic Parameters of Torrefaction Process of Alternative Fuel Produced From Municipal Solid Waste and Characteristic of Carbonized Refuse Derived Fuel

Torrefaction of Healthy and Beetle Kill Pine and Co-Combustion With Sub-Bituminous Coal

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