Impact Of Torrefaction Research Articles

Impact of Torrefaction on Fuel Properties of Aspiration Cleaning Residues.

To maximise the use of biomass for energy purposes, there are various options for converting biomass to biofuels through thermochemical conversion processes, one of which is torrefaction. Higher utilisation of waste from the aspiration cleaning of grains, such as wheat or maize, could be one of the means through which the dependence on fossil fuels could be reduced in the spirit of a circular economy. In this study, the effect of torrefaction on fuel properties of agricultural residues was investigated. The tested materials were waste by-products from the aspiration cleaning of maize grains and waste from wheat. The materials were treated by torrefaction under a nitrogen atmosphere (225 °C, 250 °C, and 275 °C), over a residence time of 30 min. During the treatment, weight loss was monitored as a function of time. Proximate and elemental composition, as well as calorific values, were analysed before and after torrefaction. Torrefaction has a positive effect on the properties of the fuels in the samples studied, as shown by the results. The carbon content increased the most between temperatures of 250 °C and 275 °C, i.e., by 11.7% wt. in waste from maize. The oxygen content in the maize waste samples decreased by 38.99% wt. after torrefaction, and in wheat waste, it decreased by 37.20% wt. compared to the original. The net calorific value increased with increasing temperatures of process and reached a value of 23.56 MJ·kg−1 at a peak temperature of 275 °C in by-products from maize. To express the influence of the treatments on combustion behaviour, stoichiometric combustion calculations were performed. Differences of up to 20% in stoichiometric combustion parameters were found between the two types of waste. A similar case was found for fuel consumption, where a difference of 19% was achieved for torrefaction at a temperature of 275 °C, which fundamentally differentiated these fuels.

Impact of torrefaction on thermal behavior of wheat straw and groundnut stalk biomass: Kinetic and thermodynamic study

This study investigates the physicochemical behavior of Wheat Straw and Groundnut Stalk biomass and its impact on the thermal behavior during torrefaction process. The torrefaction was experimentally investigated by thermogravimetric analysis (TGA) at five isothermal heating rates of 20, 30, 40 and 50 °C/min. Results revealed that during the torrefaction process, significant fraction of hemicellulose and volatile content reduces that improves the high heating value. The results indicated that torrefaction treatment improved the fuel properties with elevated torrefaction temperature, including the lower volatile content, higher carbon content, and higher heating value. Kinetic parameter analysis indicated that the Ozawa–Flynn–Wall and Starink model were significant in calculating the activation energy, and the average activation energy was 240 kJ/mol and 238 kJ/mol (Wheat Stalk and torrified wheat Stalk) 127 kJ/mol and 129 kJ/mol (Groundnut Stalk and torrified Groundnut Stalk). An excellent linear relationship between lnA and Eα was observed, indicating that the compensation effect existed between the Eα and lnA during torrification. These results provide important basic data support for the thermochemical conversion of cornstalk to energy and chemicals.

Impact of Torrefaction and Alkali Pretreatment on Glucose Production From Wheat Straw

Highlights Glucose yield from torrefied wheat straw is improved when samples are subjected to alkaline pretreatment. Torrefaction time, temperature, and alkaline treatment all impact yields. Glucose yield from torrefied material, on a “per treated gram” basis, approaches that of raw feedstock in some cases. Optimized process and plant design could make torrefied feedstock a viable option for biofuel production. Abstract. The impact of torrefaction, alkaline pretreatment, and their combination on enzymatic hydrolysis was explored in terms of their effect on glucose yield from wheat straw. Samples were ground and torrefied at varying degrees of process severity, subjected to enzymatic hydrolysis, and analyzed for glucose yield. While glucose yield from raw biomass averaged 190.1 mg per g of dry raw biomass, the yield from torrefied samples was lower, ranging from 0.0 to 63.8 mg g-1, depending on the duration and temperature of the torrefaction process. Alkaline pretreatment increased the glucose yield of raw biomass to an average of 354.9 mg g-1. The highest glucose yield of 359.1 mg glucose g-1 was achieved for samples that were pretreated with a 1% NaOH solution. Alkaline pretreatment after torrefaction but prior to hydrolysis results in glucose yields ranging from 1.2 to 318.2 mg g-1, which are higher than the yields from torrefied-only samples but lower than those of raw, alkaline pretreated samples. When measured on a “per torrefied g” basis, yields of torrefied, alkaline pretreated samples approach those of raw biomass. These results indicate that there may be potential to use torrefaction and hydrolysis together when combined with an alkaline solution pretreatment. Keywords: Alkaline Pretreatment, Enzymatic hydrolysis, Lignocellulosic waste, Torrefaction, Wheat straw.

Impact of Torrefaction on Thermal Behavior of Wheat Straw and Groundnut Stalk Biomass: Kinetic and Thermodynamic Study

Impact of Torrefaction on Thermal Behavior of Wheat Straw and Groundnut Stalk Biomass: Kinetic and Thermodynamic Study

A Study of Impact of Torrefaction on Thermal Behavior of Wheat Straw and Groundnut Stalk Biomass from Punjab, India: Kinetic and Thermodynamic Approach

A Study of Impact of Torrefaction on Thermal Behavior of Wheat Straw and Groundnut Stalk Biomass from Punjab, India: Kinetic and Thermodynamic Approach

Spruce and Barley Elemental and Stochiometric Analysis Affected by the Impact of Pellet Production and Torrefaction

Abstract Biomass is a potential biofuel which may help fighting high carbon dioxide emissions and negative impacts of global warming. Analysis of Norway spruce (Picea abies) and barley (Hordeum vulgare) were performed at the laboratory of Czech University of Life Sciences. Material was torrefied in an inert nitrogen atmosphere at the temperatures of 250 °C and 280 °C for 45 minutes. Elementary and stoichiometric parameters were monitored and impact of torrefaction and pellet production on carbon footprint was determined. Torrefied and pelleted material showed better fuel properties in comparison to the original material. Calorific value of the torrefied spruce wood chip increased by 12.27% when torrefied at the temperature of 250 °C, and by 25.41% when torrefied at the temperature of 280 °C.

Thermal decomposition behavior and sulfur release characteristics for torrefied wheat straw during pyrolysis process

Understanding the release characteristics of S for pyrolysis process is crucial to the development of biomass thermochemical conversion. The thermal decomposition behavior and S release characteristics for torrefaction and pyrolysis process as well as the impact of torrefaction on the S release during subsequent pyrolysis process of wheat straw were evaluated. In the case of torrefaction, high reaction temperature promoted the increase in S release percentage, which was linearly proportional to mass loss. For pyrolysis process, the release percentage of S increased rapidly up to 70.50% at 500 ℃, whereas the release percentage curve showed an unchanged trend for further increase of the pyrolysis temperature. Additionally, torrefaction pretreatment enhanced the pore properties of char, which promoted the physical resistance of released S during the diffusion process. Thus, torrefaction pretreatment effectively inhibited the release of S into the gas phase, and has a promoting effect on retaining more S in char.

Thermal degradation of kenaf (Hibiscus cannabinus L.): Impact of torrefaction on pyrolysis kinetics and thermal behavior

Pre-treatment of biomass has garnered significant research attention to facilitate biomass utilization. This study examines the effect of torrefaction on the pyrolysis characteristics of kenaf (Hibiscus cannabinus L.), which grows in South Korea and has a relatively short life cycle as well as a low production cost among herbaceous biomass. In this study, raw kenaf (RK) and torrefied kenaf (TK) were prepared in an inert atmosphere. Torrefaction was carried out in a bed reactor for 30 min at 503, 523 and 553 K, and pyrolysis was performed at six heating rates and analyzed using thermogravimetric analysis. The results showed that the optimal temperature for RK torrefaction based on the energy-mass co-benefit index was 523 K, owing to a higher energy density and low volume. The torrefaction and a higher heating rate resulted in the weight loss and decomposition rate (derivative thermogravimetric) curves moving to a higher temperature region, and improvement in the devolatilization index of the TK. The activation energy was calculated using three methods (Kissinger, Flynn–Wall–Ozawa, and Kissinger–Akahira–Sunose), with all indicating that the activation energy of the TK was greater than that of RK. Additionally, in terms of thermodynamic parameters, the TK had a higher frequency factor, higher enthalpy, slightly lower Gibbs free energy, and higher entropy than those of RK. These kinetic and thermal behavior results are useful for designing pyrolysis processes wherein TK is used as a feedstock; moreover, they provide a useful reference for TK heat conversion applications.

Impact of torrefaction on entrained-flow gasification of pine sawdust: An experimental investigation

Entrained-flow gasification of raw and torrefied pine sawdust (PS) was conducted at 1300 °C and different equivalence ratios (ERs). The effects of torrefaction conditions on gasification performance as well as the relationship between soot yield and the volatile content of feedstocks were investigated. An additional burning procedure after gasification was used to quantify the carbon deposits (CD) inside the reactor tube, which completed the mass balance calculation and thus enabled reliable conclusions to be made. The results of the entrained-flow gasification tests indicated that PS torrefied at 280 °C exhibited a better gasification performance than raw PS and PS torrefied at other temperatures. Moreover, it was found that torrefaction pretreatment also reduced soot yield. These results indicated that the total yield of soot and CD is closely related to the content of volatile matter in feedstocks.

Impact of torrefaction on biomass properties depending on temperature and operation time

Torrefaction is an effective way to upgrade biomass for producing fuels. The experimental results of torrefaction for three materials, oak wood, mixed wood mainly from deciduous trees and sewage sludge are presented. The comparison between three materials is performed to evaluate the influence of temperature and time on torrefaction operation. The influence of the operating temperature and time was analysed in order to determine optimal operation parameters for the newly developed process which has been patented. Properties, such as heating value, mass loss, chemical compositions, energy yield and enhancement factor were investigated. The results show that from an energy point of view the optimal operation time for oak and mixed wood is around 1.2 h at 260 °C. The torrefaction of sewage sludge is energetically unjustified. The highest carbon loss is shown for mixed wood, following by sewage sludge and oak wood. Torrefaction severity index was established based on the, most severe conditions. Torrefaction severity index could be applied as an indicator for prediction of torrefaction efficiency of chosen material.

Impact of Torrefaction on Vine Pruning’s Fuel Characteristics

AbstractAgricultural and waste-derived solid biomass fuels are available in vast amounts for the generation of sustainable energy. Since these fuels usually have rather low heating values, low bulk...

Torrefaction, pyrolysis and two-stage thermodegradation of hemicellulose, cellulose and lignin

This study aims to investigate the thermal degradation mechanisms of hemicellulose, cellulose, and lignin using pyrolysis–gas chromatography/mass spectrometry. To characterize the decomposition behaviors, the torrefaction, pyrolysis, and their combination of the three constituents are performed using single-shot and double-shot reactions, with emphasis on the influence of torrefaction upon pyrolysis. The analysis suggests that O-acetyl and pentose units contained in the hemicellulose are thermally degraded into acetic acid and furfural in torrefaction, so acetic acid and furfural contents decrease significantly in the pyrolysis of torrefied hemicellulose. The impact of torrefaction upon cellulose is insignificant, resulting from the high thermal stability of the crystalline structure in the cellulose. When the pyrolysis temperature is higher than 300 °C, the cellulose starts to decompose and form organic volatile products. The products from lignin mild torrefaction at 250 °C are not obvious, except for vanillin. The severe torrefaction at 300 °C has a significant influence on lignin pyrolysis, and the pyrolysis of torrefied lignin results in an increase in aromatic compounds. Overall, the analysis suggests that torrefaction can be applied for biomass pyrolysis to stabilize pyrolysis bio-oil, make its composition more uniform, and separate certain chemicals. Based on the thermal degradation of the three main biomass components from torrefaction, pyrolysis, and their combination analyzed by Py-GC/MS, the obtained findings have provided useful insights into the applications of torrefaction, pyrolysis, and their combination for biofuel production.

Investigation of ash deposition in PF boiler during combustion of torrefied biomass

The paper presents an analysis concerning the propensity of torrefied biomass to slagging and fouling and impact of its combustion on heat exchange in existing pulverized fuel boiler in reference to Polish coal. The impact of torrefaction on slagging properties was also investigated. Based on the results of ash composition and fusibility analyses the most common ash deposition indices were determined. The effect of ash composition and its particle sizes on thermal efficiency of convective heating surfaces in boiler was analysed. Additionally, influence of fuel change at the nature of heat transfer in boiler, mainly at the flue gas temperature distribution and boiler efficiency, was also presented. The results may be used as a basis of experimental, in lab-scale as well as in technical-scale, research planning and of slagging and fouling prevention guidelines for boilers operators.

Virginia Mallow as an energy crop - current status and energy perspectives

Currently, the energy crops are designed as promising renewable energy source. The most popular are Miscanthus Giganteus, willow and Virginia mallow. They are well known as plans, but use as a fuel in energy production still needs more investigations. It results from some disadvantages such as biological degradation, low bulk density and low energy density of Virginia mallow. That is why, pre-treatment processes are required to enhance combustible properties. Thus, this paper demonstrates the current state and energy perspectives of Virginia mallow which can be one of the most promising energy crops in Poland. The study of Virginia mallow focuses on combustion characteristics of torrefied biomass using both experiments and modelling. This energy crop was torrefied using TGA apparatus. The studied biomass was characterized in terms of its ultimate and proximate analysis. After the torrefaction process of Virginia mallow, improvements in energy properties were observed. The impact of torrefaction was confirmed by enhancing fuels properties (higher carbon content, and HHV, lower moisture content, lower ratio O/C). The Chemkin calculations showed changes in composition of the main evolved gaseous products.

Influence of torrefaction on properties of activated carbon obtained from physical activation of pyrolysis char

ABSTRACTIn this paper, the method of ‘torrefaction–fast pyrolysis–physical activation’ was conducted to investigate the impact of torrefaction on the properties of activated carbon through CO2 activation. It was found that torrefaction had a significantly positive influence on the quality of activated carbon and 280°C was the optimal torrefaction temperature. The activated carbon obtained under the recommended condition had a higher yield (13.0 ± 0.3% based on dried rice husk) and most developed pore structure (specific surface area of 1090.7 m2/g). The results may be helpful for the potential utilization of high ash content biomass like rice husk.

NO and SO2 emissions from combustion of raw and torrefied biomasses and their blends with lignite

The impact of torrefaction on the NO and SO2 emissions from combustion of biomass was investigated. Combustion experiments were carried out with two torrefied biomass fuels, i.e., poultry litter and olive tree pruning and their blends with lignite using a bench scale single particle reactor. For comparison, NO and SO2 emissions from tests with untorrefied biomasses and their blends with lignite were also investigated. The total release of SO2 and NO for each fuel was determined at three different temperatures: 900, 1000, and 1100 °C. The NO release from the untorrefied biomasses was found to be lower than those from torrefied biomasses, despite their higher fuel- N content. In case of co-combustion of both raw and torrefied biomass with lignite, the NO release was lower than the anticipated one. On the other hand, in the co-combustion experiments, blends with torrefied biomass showed a larger reduction in SO2 release than the blends with raw biomass.The study revealed that the SO2 emissions from blends are not proportional to the mixing ratio of the fuels and to the emissions properties of the respective fuels. No clear correlation was detected between the NOx emissions and fuel-N content. In addition to the NO and SO2 emissions, the sintering propensity of the ash residue were investigated using scanning electron microscopy (SEM).

Impact of Torrefaction on the Fuel Properties and Combustion Characteristics of Compost of Food Waste and Sawdust

With rapid global development, the amount of food waste is increasing, which has seriously affected the environment. Usually, food waste is composted with sawdust to prevent environmental pollution due to the loss of N and S. Unfortunately, the quality of the compost of food waste and sawdust (CFS) is poor, and the material is hard to handle. Torrefaction, a process of slow pyrolysis under anoxic conditions, can be used to improve the properties of a fuel sample. This study investigated the fuel properties of CFS samples subjected to torrefaction at five different temperatures (250, 300, 350, 400 and 450°C) and residence times of 30 min. Physicochemical analyses of the samples were carried out according to standard methods, and the combustion characteristics of the samples were studied by thermogravimetric analysis. Torrefaction has great impact on proximate and ultimate analysis, chlorine contents, energy and mass yields, grindability and combustion characteristcs. The grindability and combustion propert...

Impact of Torrefaction on the Properties of Food Waste Compost

Impact of Torrefaction on the Properties of Food Waste Compost

Effects of torrefaction on physical properties, chemical composition and reactivity of microalgae

Torrefaction of the microalga Chlorella vulgaris was carried out in a fixed-bed tubular reactor under various conditions of temperature (150–300 °C), time (15–60 min), and atmosphere (inert or oxidative). The impact of torrefaction and its various conditions on the mass yield, physical properties, chemical composition, and reactivity of the microalgal biomass was assessed and compared with those of the raw material. After torrefaction, the morphology, proximate analysis, ultimate analysis, higher heating value analysis, chemical compositions, and thermal behavior of the biomass were carried out. The results show that torrefaction temperature influenced mass yield and changes in the microalgae’s properties more than torrefaction time and atmosphere. Torrefaction at 200 °C, for 30 min in an inert atmosphere led to the highest calorific value of torrefied microalgae. In addition, torrefaction reduced the thermal degradation rates of the remaining protein and carbohydrate fractions in the biomass, but accelerated the degradation rate of the lipids fraction.

Impact of Torrefaction on Woody Biomass Properties

Abstract In this work, Norway spruce stem wood, stump and bark were torrefied in a tubular reactor. The effects of feedstock type and torrefaction process parameters such as torrefaction temperature and residence time on the grindability and chemical properties of the torrefied biomass samples were investigated. In comparison to torrefaction temperature, torrefaction residence time had smaller effects on the grindability of stem wood and stump. For raw bark, much less grinding energy is required compared to those for raw stem wood and stump. Torrefaction has minor effects on grindability of the bark. The cellulose contents of stem wood and stump were reduced slightly at a torrefaction temperature of 275 °C. On the contrary, the cellulose content of the torrefied bark drastically decreased already at a torrefaction temperature of 275 °C, with only trace amounts left in the 300 °C torrefied products.