Torrefaction of almond shells: Effects of torrefaction conditions on properties of solid and condensate products

Chiou, Bor‐Sen; Valenzuela-Medina, Diana; Bilbao‐Sainz, Cristina; Klamczynski, Artur; Avena‐Bustillos, Roberto J.; Milczarek, Rebecca R.; Du, Wenjie; Glenn, Greg; Orts, William J.

doi:10.1016/j.indcrop.2016.03.030

Cited by 52 publications

(18 citation statements)

References 40 publications

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“…Some novel applications of almond shells are being continuously proposed, such as heavy metal adsorbents, dye absorbents, growing media, activated carbon preparation, and additives for the preparation of xylooligosaccharides (XOs) (Deniz, 2013;Doulati Ardejani et al, 2008;Ebringerová et al, 2007;Esfahlan et al, 2010;Urrestarazu et al, 2005). However, currently almond shells are mainly incinerated (Chiou et al, 2016) or used as animal feed (Ledbetter, 2008). Additionally, it is worth to note that the processing byproducts, i.e., hulls and shells, account for more than 50% by dry weight of the almond fruit (Fadel, 1999).…”

Section: Introductionmentioning

confidence: 99%

Compatibilization of highly sustainable polylactide/almond shell flour composites by reactive extrusion with maleinized linseed oil

Quiles-Carrillo

Muñoz

Sammon

et al. 2018

Industrial Crops and Products

116

122

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Highly sustainable composites were produced by melt compounding polylactide (PLA) with almond shell flour (ASF), a processed byproduct of the food industry, at a weight content of 30 wt.-%. However, due to the lack of miscibility between PLA and ASF, both being raw materials obtained from crops, resultant green composite presented poor ductility and low thermal stability. To overcome this limitation, maleinized linseed oil (MLO), a multi-functionalized plant-derived additive, was originally incorporated as a reactive compatibilizer during the extrusion process. Both chemical and physical characterizations showed that 1-5 parts per hundred resin (phr) of MLO successfully serve to function as a novel compatibilizer on the PLA/ASF composites, leading to highly sustainable materials with balanced mechanical, thermal, and thermomechanical properties. Achieved compatibilization was particularly related to a dual effect of plasticization in combination with grafting. The latter effect was ascribed to the formation of new carboxylic ester bonds through the reaction of the multiple maleic anhydride groups present in MLO with the hydroxyl terminal groups of both PLA chains and lignocellulose on the ASF surface. The fully bio-based and 2 biodegradable composites described herein give an efficient sustainable solution to upgrade agrofood wastes as well as contributing to reducing the cost of PLA-based materials.

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Section: Introductionmentioning

confidence: 99%

Compatibilization of highly sustainable polylactide/almond shell flour composites by reactive extrusion with maleinized linseed oil

Quiles-Carrillo

Muñoz

Sammon

et al. 2018

Industrial Crops and Products

116

122

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“…Therefore, seeking an effective pretreatment method of raw materials to reduce the oxygen content and improve the quality of bio-oil has become the focus of current research. Recent studies have shown that torrefaction can greatly improve the quality of bio-oil by lowering the acidity and oxygen content and increasing the biomass pyrolysis characteristics and the energy content (Bridgeman et al 2008;Chew and Doshi 2011;Chiou et al 2016;Mafu et al 2016;Matali et al 2016). Torrefaction is a medium thermo-chemical conversion technology that operates under a relatively low heating temperature (200 to 300 °C), a relatively low atmospheric pressure, and in an inert environment.…”

Section: Introductionmentioning

confidence: 99%

Effect of the Torrefaction Temperature on the Structural Properties and Pyrolysis Behavior of Biomass

Zheng¹,

Tao²,

Yang³

et al. 2017

BioResources

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To improve prospects for high-value utilization of biomass, torrefaction pretreatments were conducted at 210, 230, 250, 270, and 300 °C with a reaction time of 30 min. The pyrolysis of torrefied biomass was also performed on a fixed-bed reactor system at 450 °C. The effect of torrefaction temperature on the yield, energy yield, structure, physicalchemical characteristics, and production composition of bio-oil was studied. The torrefaction pretreatment improved the fuel characteristics of pyrolysis products. When the torrefaction temperature was increased, the -OH and C=O contents decreased, the C=C contents increased, the pyrolysis peak temperature decreased, the residual carbon contents noticeably increased, and the Ea value remained in the range of 69 to 129 kJmol -1. The pore volume increased and the crystallinity index decreased due to degradation and recrystallization. The solid yield of pyrolysis biomass decreased sharply in contrast to the liquid yield. When the torrefaction temperature increased, the bio-oil yield decreased from 36.82 wt.% to 20.13 wt.%. The phenol content in the bio-oil markedly increased; however, oxygen-containing compounds such as acids, sugars, and furans, significantly decreased, which indicated that torrefaction pretreatment efficiently improved the quality of the fuel.

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“…According to the literature there are a few studies regarding almond and walnut shells torrefaction (Arnsfeld et al, 2014;Chiou et al, 2015Chiou et al, , 2016Zhu et al, 2019). The mentioned manuscripts have assessed the properties of resulting torrefaction products of almond and walnut shells and the pretreatments to improve the torrefaction processes.…”

Section: Introductionmentioning

confidence: 99%

“…The results indicate that torrefaction is a successful alternative to only incinerating the shells. Both almond and walnut shells present high solid and energy yields during torrefaction (Barskov et al, 2019) while maintaining low sulfur content, making it interesting to US power plants (Chiou et al, 2016). However, the torrefaction products are dependent on residence time but mostly temperature applied (Chiou et al, 2016), thus making torrefaction studies crucial to determine optimal production.…”

Section: Introductionmentioning

confidence: 99%

“…Utilization of torrefied biomass as a fillers in plastic composites addresses waste issues associated with both plastic and agricultural by-product (Zou et al, 2010;Arrakhiz et al, 2012;Peng et al, 2012;Chiou et al, 2016;Dikobe and Luyt, 2017;Sanjay et al, 2018). Torrefaction is used to improve the compatibility between filler and polymer by increasing the hydrophobicity of the filler (Zaghloul et al, 2017).…”

Section: Introductionmentioning

confidence: 99%

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Torrefaction of Almond and Walnut Byproducts

et al. 2021

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While the US nut industry is growing, markets for nut by-products, particularly nutshells and tree prunings, have not kept pace. Torrefaction is a thermochemical process used to improve physicochemical properties of biomass for energy and other applications. The goal of the paper was to characterize the effects of a range of torrefaction conditions on the properties of nut by-product feedstock. The process consists of thermal treatment of biomass at a temperature between 200 and 300°C in the absence of oxygen, where final material properties of the torrefied biomass depend on the temperature, heating rate, and residence time. In general, torrefied biomass exhibits higher hydrophobicity and calorific value with reduced moisture absorption compared to untreated biomass, making it an ideal fuel source for energy applications compared to raw biomass. In this study, almond shells of soft, semi-soft, and hardshell varieties, as well as walnut shells and almond wood, were torrefied at two different temperatures (230 and 290°C) and three different residence times (20, 40, and 60 min) in order to characterize the physicochemical properties. The thermal behavior of raw and heat-treated biomass was investigated by TGA analysis, elemental analysis, pH, helium pycnometry, FTIR spectroscopy, and dynamic vapor sorption analysis.

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Torrefaction of almond shells: Effects of torrefaction conditions on properties of solid and condensate products

Cited by 52 publications

References 40 publications

Compatibilization of highly sustainable polylactide/almond shell flour composites by reactive extrusion with maleinized linseed oil

Compatibilization of highly sustainable polylactide/almond shell flour composites by reactive extrusion with maleinized linseed oil

Effect of the Torrefaction Temperature on the Structural Properties and Pyrolysis Behavior of Biomass

Torrefaction of Almond and Walnut Byproducts

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