Oxytree Pruned Biomass Torrefaction: Mathematical Models of the Influence of Temperature and Residence Time on Fuel Properties Improvement

Świechowski, Kacper; Liszewski, Marek; Bąbelewski, P.; Kozieł, Jacek A.; Białowiec, Andrzej

doi:10.3390/ma12142228

Cited by 22 publications

(22 citation statements)

References 31 publications

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“…Therefore, there was an effect of concentrating the solid material, resulting in an increase of ash content in the fuel. Other biomass materials like wood sawdust and chips, investigated by Świechowski et al [53], also had a higher ash content at a higher temperature of the torrefaction process. Their research showed that torrefied pruned biomass (oxytree wood) at a temperature of 200 °C contained below 10% of ash.…”

Section: Resultsmentioning

confidence: 99%

The Influence of Torrefaction Temperature on Hydrophobic Properties of Waste Biomass from Food Processing

2019

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The annual potential of waste biomass production from food processing in Europe is 16.9 million tonnes. Unfortunately, most of these organic wastes are utilized without the energy gain, mainly due to the high moisture content and the ability to the fast rotting and decomposition. One of the options to increase its value in terms of energy applications is to valorize its properties. Torrefaction process is one of the pre-treatment technology of raw biomass that increases the quality of the fuel, especially in the context of resistance to moisture absorption. However, little is known about the influence of torrefaction temperature on the degree of valorization of some specific waste biomass. The aim of this paper was to analyze the influence of the temperature of the torrefaction on the hydrophobic properties of waste biomass, such as black currant pomace, apple pomace, orange peels, walnut shells, and pumpkin seeds. The torrefaction process was carried out at temperatures of 200 °C, 220 °C, 240 °C, 260 °C, 280 °C, and 300 °C. The hydrophobic properties were analyzed using the water drop penetration time (WDPT) test. The torrefied waste biomass was compared with the raw material dried at 105 °C. The obtained results revealed that subjecting the biomass to the torrefaction process improved its hydrophobic properties. Biomass samples changed their hydrophobic properties from hydrophilic to extremely hydrophobic depending on the temperature of the process. Apple pomace was the most hydrophilic sample; its water drop penetration was under 60 s. Black currant and apple pomaces reached extremely hydrophobic properties at a temperature of 300 °C, only. In the case of orange peels, walnut shells, and pumpkin seeds, already at the temperature of 220 °C, the samples were characterized by severely hydrophobic properties with a penetration time over 1000 s. At the temperature of 260 °C, orange peels, walnut shells, and pumpkin seeds reached extremely hydrophobic properties. Furthermore, in most cases, the increase of torrefaction temperature improved the resistance to moisture absorption, which is probably related to the removal of hydroxyl groups and structural changes occurring during this thermal process.

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Section: Resultsmentioning

confidence: 99%

The Influence of Torrefaction Temperature on Hydrophobic Properties of Waste Biomass from Food Processing

2019

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“…Based on these results and using the best variant (T and t), a simple model [49] was proposed (after some modifications) for estimating the possibility of achieving heat self-sufficiency of biocoal production. The model also calculates the theoretical mass yield after biocoal recirculation of the torrefied biomass to maintain the torrefaction process itself (biocoal recirculation- Figure 1).…”

Section: Resultsmentioning

confidence: 99%

“…Heat need for torrefaction process: Data for calculations [49]: The heat needed to heat water contained in MSC:…”

Section: Main Properties Of Torrefied Biomass Calculationsmentioning

confidence: 99%

Proof-of-Concept of Spent Mushrooms Compost Torrefaction—Studying the Process Kinetics and the Influence of Temperature and Duration on the Calorific Value of the Produced Biocoal

2019

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Poland, being the 3rd largest and growing producer of mushrooms in the world, generates almost 25% of the total European production. The generation rate of waste mushroom spent compost (MSC) amounts to 5 kg per 1 kg of mushrooms produced. We proposed the MSC treatment via torrefaction for the production of solid fuel—biocoal. In this research, we examined the MSC torrefaction kinetics using thermogravimetric analyses (TGA) and we tested the influence of torrefaction temperature within the range from 200 to 300 °C and treatment time lasting from 20 to 60 min on the resulting biocoal’s (fuel) properties. The estimated value of the torrefaction activation energy of MSC was 22.3 kJ mol−1. The highest calorific value = 17.9 MJ kg−1 d.m. was found for 280 °C (60 min torrefaction time). A significant (p < 0.05) influence of torrefaction temperature on HHV increase within the same group of torrefaction duration, i.e., 20, 40, or 60 min, was observed. The torrefaction duration significantly (p < 0.05) increased the HHV for 220 °C and decreased HHV for 300 °C. The highest mass yield (98.5%) was found for 220 °C (60 min), while the highest energy yield was found for 280 °C (60 min). In addition, estimations of the biocoal recirculation rate to maintain the heat self-sufficiency of MSC torrefaction were made. The net quantity of biocoal (torrefied MSC; 65.3% moisture content) and the 280 °C (60 min) torrefaction variant was used. The initial mass and energy balance showed that MSC torrefaction might be feasible and self-sufficient for heat when ~43.6% of produced biocoal is recirculated to supply the heat for torrefaction. Thus, we have shown a concept for an alternative utilization of abundant biowaste (MSC). This research provides a basis for alternative use of an abundant biowaste and can help charting improved, sustainable mushroom production.

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“…where HHV-high heating value (on dry basis), MJ•kg -1 ; M f -fuel mass (on dry basis), mass, g; M ash -the mass of ash in fuel, g. Multiple regression analysis at the significance level p < 0.05 was then performed to elucidate the influence of process temperature and residence time on biochars fuel and fertilizer properties. Finally, the polynomial models of process temperature and residence time influence on biochars fuel properties were used according to the previous study [60] with regression modeling:…”

Section: Discussionmentioning

confidence: 99%

Waste-to-Carbon: Is the Torrefied Sewage Sludge with High Ash Content a Better Fuel or Fertilizer?

et al. 2020

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Sewage sludge (SS) recycling is an important part of the proposed ‘circular economy’ concept. SS can be valorized via torrefaction (also known as ‘low-temperature pyrolysis’ or ‘roasting’). SS can, therefore, be considered a low-quality fuel or a source of nutrients essential for plant growth. Biochar produced by torrefaction of SS is a form of carbonized fuel or fertilizer. In this research, for the first time, we tested the feasibility of torrefaction of SS with high ash content for either fuel or organic fertilizer production. The research was conducted in 18 variants (six torrefaction temperatures between 200~300 °C, and three process residence times of 20, 40, 60 min) in 5 repetitions. Fuel and fertilizer properties and multiple regression analysis of produced biochar were conducted. The higher heating value (HHV) of raw SS was 21.2 MJ·kg−1. Produced biochar was characterized by HHV up to 12.85 MJ·kg−1 and lower H/C and O/C molar ratio. Therefore, torrefaction of SS with high ash content should not be considered as a method for improving the fuel properties. Instead, the production of fertilizer appears to be favorable. The torrefaction increased C, N, Mg, Ca, K, Na concentration in relation to raw SS. No significant (p < 0.05) influence of the increase of temperature and residence time on the increase of biogenic elements in biochar was found, however the highest biogenic element content, were found in biochar produced for 60 min, under the temperature ranging from 200 to 240 °C. Obtained biochars met the Polish regulatory criteria for mineral-organic fertilizer. Therefore SS torrefaction may be considered a feasible waste recycling technology. The calculation of torrefaction energy and the mass balance shows energy demand <2.5 GJ∙Mg−1 w.m., and the expected mass yield of the product, organic fertilizer, is ~178 kg∙Mg−1 w.m of SS. Further investigation should consider the scaling-up of the SS torrefaction process, with the application of other types of SSs.

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Oxytree Pruned Biomass Torrefaction: Mathematical Models of the Influence of Temperature and Residence Time on Fuel Properties Improvement

Cited by 22 publications

References 31 publications

The Influence of Torrefaction Temperature on Hydrophobic Properties of Waste Biomass from Food Processing

The Influence of Torrefaction Temperature on Hydrophobic Properties of Waste Biomass from Food Processing

Proof-of-Concept of Spent Mushrooms Compost Torrefaction—Studying the Process Kinetics and the Influence of Temperature and Duration on the Calorific Value of the Produced Biocoal

Waste-to-Carbon: Is the Torrefied Sewage Sludge with High Ash Content a Better Fuel or Fertilizer?

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