Reduction In Ash Content Research Articles

Reduction of sulfur and ash contents from low-rank coal

This research attempted to reduce sulfur and ash content for enhanced coal recovery by the froth flotation technique. Dukki district (Pakistan) coal was upgraded using a flotation technique followed by acid leaching. Tests on flotation concentrate were carried out to improve the grade of coal further. Tests were carried out to investigate and determine the effect of critical parameters like particle size, pH, and pulp density on reducing ash and sulfur content from coal. The particle size was observed to have the most significant role in coal ash and sulfur reduction, followed by the pH, and pulp density, respectively. The optimum particle size, pH, and pulp density values were 74 μm, 9 and 10%, respectively. The results from the flotation study on a laboratory scale at optimized conditions were a 54.1% increase in total carbon, a 42.12% reduction in ash, and a 38.32% reduction in sulfur. Final ash and sulphur contents in clean coal were 15.2% and 1.65%, respectively. Thus, clean coal can preferably be used in power plants and the cement industry in the country.

The Influence of the Long-Term Outdoor Storage of Rockrose (Cistus laurifolius L.) Shrub Biomass on Biofuel's Quality, Pre-Treatment and Combustion Processes.

Biomass storage is an essential requirement in the supply chain of bio-refineries and power plants. This research aims to evaluate the influence of long-term outdoor storage (1 year) of baled rockrose (Cistus laurifolius L.) shrub biomass on biofuel's quality, pre-treatment processes and on combustion emissions in an industrial boiler. The raw material was obtained from different rockrose shrublands in north central Spain. A total of 233 tWM (tones of wet matter) of biomass were used to produce biofuels (30 mm of milled biomass and Ø 8 mm pellets) in the pre-treatment pilot plants at CEDER-CIEMAT. The combustion tests were conducted in an industrial moving grate boiler with a thermal power of 50 MWth, in a 17 MWe power plant. Outdoor storage improved some biofuel quality parameters, mainly the reduction in ash content, which allowed 30 mm of milled material to be classified as class I1 (ISO 17225-9:2022) and pellets as class I3 (ISO 17225-2-2021). No significant differences were observed in the total specific mass flow and energy consumption in the pre-treatment processes. The combustion tests had similar results, with the emissions being below the limits established in the directive (EU) 2015/2193. The results obtained indicated that the 1-year outdoor storage of rockrose-baled biomass, under Mediterranean conditions, was feasible for its subsequent use as biofuel.

Thermal extraction of coal and derivatives to prepare hot-pressed coal briquette for COREX application

In this study, the thermal extraction of various coal and derivatives by N-methylpyrrolidone was systematically compared and the extract was used as binder to prepare hot-pressed coal briquettes (HPCBs). The results demonstrate the effectiveness of thermal extraction in converting coal to HyperCoal, and the conversion yields varied from 12 to 71%. While the extraction tends to have a linear relationship with hydrogen-carbon ratio of raw coals, this relationship was not directly observed for derivatives due to inherent changes occurring during production. Proximate analysis of the extract reveals a reduction in ash content to below 1% while an increase in volatile matter by more than 8%. XPS and FTIR spectra demonstrate the high efficiency of thermal extraction in extracting hydrocarbons, but poor for compounds such as alcohols, phenols, ethers, and carboxylic acids. The extracts, rich in hydrocarbons, exhibited excellent thermoplasticity, making them suitable binders for HPCBs preparation. Among the extracts, coal derivatives exhibited higher compressive strength compared to coals. Consequently, the extract derived from direct coal liquefaction residue with the highest compressive strength was selected for preparing HPCB. Furthermore, we investigated the application characteristics of the HPCB and identified its great potential for use in COREX melting-reduction ironmaking. The preparation of HPCB is vital for expanding the utilization of bituminous coals while reducing dependence on lump coal and coking coal resources.

Preparation and Characterization of Fish Protein Isolate from Tiger Tooth Croaker (Otholithus ruber) Obtained through PH Shift Method

Development of Fish Protein Isolate (FPI) from tiger tooth croaker (Otholithus ruber) fish meat using the pH shift method was carried out during this study. Tiger tooth croaker was used as raw material because of their abundance and comparatively low price. During the study, the physical characteristics and proximate composition of the fresh fish were analysed. The average length of fish was 19.95 cm and weighed 94.6 g. respectively. FPI treated at different pH treatments (2.5, 4, 7, 11.5 and 12.5) were analyzed for proximate composition, peroxide value and functional characteristics. In the present work, Tiger tooth croaker (Otolithes ruber) fish was found to be suitable for fish protein isolate production using acid or alkali processing and isoelectric precipitation. During storage at ambient temperature for 120 days in a 200 gauge LDPE pouch, Fish Protein Isolates treated at different pH treatments (2.5, 4, 7, 11.5 and 12.5) indicated an increase in moisture content, reduction in protein and lipid content and no significant reduction in ash content. The total protein content was specifically high for pH 7 followed by pH 12.5, 11.5, 4 and 2.5. The effect of different pH on PV of fish protein isolates showed increasing content with increasing storage. The functional properties such as water-holding capacity (WHC), oil-holding capacity (OHC), emulsifying capacity (EC) and foam measurements (Foaming capacity (FC) and foam stability (FS) exhibit high values for all the samples of fish protein isolates. The quality attribute of functional properties of all fish protein isolates samples showed a trend of decreasing during the storage of 120 days.

MIL pretreatment on breaking hydrogen bond and swelling of coal: Experiment and simulation

Since direct combustion of low-rank coal is inefficient, expansion and dissolution are essential for better use of coal as an energy source. In this study, [C8mim]FeCl4 molecular configuration was synthesized by quantum chemical simulation method, and Magnetic ionic liquid (MIL) was used to modify coal to improve its swelling efficiency. The FT-IR and Raman properties of MIL were measured by simulation combined with practical methods. Dmol3 was used to study the hydrogen bond changes of coal molecules induced by MIL. When MIL interacts violently with organic matter in coal, the cross-linking network structure generated by non-covalent bonds is destroyed, resulting in the break of covalent bonds such as hydrogen bonds. Further experimental study shows that the pore structure and surface morphology of modified coal samples will be damaged, indicating that the MIL has the ability to dissolve hydrogen bonds and pretreat low-rank coal. It was found by TGA that MIL treatment can increase the tar yield of coal by up to 4.79% and reduce ash content by 3.51%. Through the integration of molecular modeling and experimental analysis, this study elucidates the fundamental principles underlying MIL pretreatment of coal, thereby providing a viable strategy for efficient quality improvement utilization of low-rank coal.

Effect of Roasting on the Proximate Composition of Corn (Zea Mays) and Meat (Beef) Sold in Nigeria

Abstract: The study shows the effect roasting has on corn (Zea mays) and meat (beef). The proximate analysis of samples was carried out using the Association of Official Analytical chemist method (AOAC, 1990). The corn and meat samples were procured from Living faith junction, Abdulrazak Street Junction, Nasarawa main market park, Angwan Power, Oversea Road junction, Opposite Tammah filling station and opposite Govt. College in Nasarawa Town. It is seen that in fresh corn samples, the moisture content is 12.50%, protein 7.00%, ash 2.20%, lipid 4.8% and carbohydrates 72.50%. While in fresh meat, the moisture content is 69.75%, protein 17.98%, ash 4.12% and fats 5.23%. The average values obtained after roasting each corn samples from each location for roasted corn; moisture content is 95.70%, protein 10.50%, ash 1.20%, lipid 2:50% and carbohydrate 71.25% and that of the roasted meat; moisture content is 65.40%, protein 19.80%, ash 1.80% and fats 2.50%. The caloric values (Kcal) of fresh corn and meat are 98.74% and 97.27% respectively. This study shows that the caloric value of fresh corn to be 98.74 and 97.27 for fresh meat, after roasting the average caloric value of the food samples were slightly reduced which shows that more calories can be gotten when the food samples are consumed fresh and less calories when consumed after roasting which is good for people undergoing weight process. From the study carried out, it can be deduced that the effect of roasting corn and meat has resulted in reduction in ash content and protein level increase. High protein levels are good for both old and young people. It is advisable to consume meat and corn in their roasted forms. In normal handling and storage of meat, the major deteriorative changes are attributed to microbial contamination and activity. Keywords: Lipid: Protein: Proximate: Composition: Nutrition: Components: Moisture: Ash Content.

The Effects of Demineralization on Reducing Ash Content in Corn and Soy Biomass with the Goal of Increasing Biofuel Quality

The increasing amount of residual waste presents several opportunities to use biomass as a renewable energy source. Agricultural biomass is a raw material with a high ash content, which can be a problem in any form of energy conversion. To obtain better quality biofuel, excess mineral matter must be removed. Demineralization is a simple form of mixing and washing biomass with various liquids to reduce ash content. Water, acetic acid, hydrochloric acid and nitric acid are common solvents used for this purpose. Ash is composed of different micro (Zn, Cu, Fe) and macro elements (Mg, Ca, K), which can have different consequences for the use of biomass for thermal energy. Different solvents have different effects on the individual elements, with inorganic acids having the greatest effect in demineralization processes, with a reduction in ash content of up to 80% for corn and about 99% for soybeans.

A Study on Chemical Deashing of Coal from Bulupodo Area Sinjai Regency of South Sulawesi Province Using Hydrogen Peroxide

Bulupodo coal has a fairly high ash content and low total sulphur. The main objective of this research is to reduce the ash content in Bulupodo coal. The methods used was chemical washing of coal using hydrogen peroxide (H2O2) with washing variables such as time (30 minutes, 60 minutes, 120 minutes, and 180 minutes), H2O2 concentration (5%, 10%, 15%, and 20%), temperature (45°C, 60°C, and 80°C) and particle sizes (16 mesh, 40 mesh, and 70 mesh). The results of the quality analysis show that Bulupodo coal has a moisture of 6.37%; ash 53.3%; volatile matter 26.79%; fixed carbon 14.45%; and a total sulfur of 0.53%. Hence, mineral matter analysis using microscopic and XRD (X-Ray Diffraction) show that Bulupodo coal contains kaolinite, illite, quartz, and pyrite minerals. As a result washing with the highest reduction time variable of ash content at 180 minutes was 21.63%; the concentration variable of the highest ash content reduction solution was at a concentration of 20% of 14.78%; the temperature variable for the reduction of the highest ash content at 60°C was 13.45%; and the particle size variable for the reduction of the highest ash content was at a particle size of 40 mesh of 7.32%.

Influence of physical, mechanical, and thermal properties of biomass pellets from agriculture residue: Pearl millet cob and mix

Fossil fuels such as coal are likely to be exhausted in near future, research therefore is focussed on exploration of alternatives. Biomass pellet is one such option and in this work pellets were produced from pearl millet cob, mixed with corncob and eucalyptus saw dust as additives in five different mass ratios. The influence of pelletization on physical, mechanical, and thermal characteristics of the pellets so produced for use as biofuel was studied. The biomass pellets were found to characteristically have higher calorific value, higher bulk and energy densities; and lower moisture content. The pellets produced with pearl millet cob had large ash contents (2.89 % to 6.48 %). The addition of additives caused reduction in ash content and enhanced energy characteristics of resultant biomass pellets up to significant extent. Durability of pellets were enhanced from 83.3 % for pearl millet pellets to over 95.4 % for pellets with 50 % additives. Water resistance improved from 39 s to at least 110 s with similar additives.

The effect of impregnation ratio on the yield of corn cob activated carbon by chemical activation

Agricultural waste biomass as a precursor for the synthesis of activated carbons has increased in recent years. In spite of transportation cost, agricultural waste biomass is one of an environmentally friendly, readily available and known as renewable sources compared to conventional activated carbon which is very expensive and exhaustible. That is the main reason activated carbon derived from agricultural waste biomass has been widely used in a variety of applications in the environment and industry for the separation, retrieval, modification, and removal of diverse substances in the liquid and gas phases. The purpose of this research is to produce activated carbon (AC) from corncob through carbonization followed by chemical activation with sodium hydroxide. Initially, the corncob was ground and sieved into a powder form with a mesh size of 500 µm. Later, the powder was chemically activated with sodium hydroxide at different impregnation ratios (1:1, 1:2, and 1:4) under activation temperatures of 200 oC. The percentage of carbon yield and ash content were evaluated using a mathematical approach. The results revealed that the sample impregnated at ratio of NCAC 1:4 showed the lowest ash content (6.58 %) with highest carbon yield of 20.52 %. As the impregnation ratios of sodium hydroxide increases, these entrapped chemicals in the activated corncob contributed in high carbon yield and reduced ash content.

Feeding frequency has a determinant role in growth performance, skeletal deformities, and body composition in the Mexican pike silverside (Chirostoma estor), an agastric short-intestine fish (Teleostei: Atheriniformes)

Several fish species with potential for aquaculture diversification possess agastric short-intestine anatomical configuration. The absence of a stomach or long intestine in fish may imply specific feeding frequency strategies for optimal growth. Because adequate feeding frequencies are paramount for thriving fish culture, the present study aimed to evaluate the effects of feeding frequency on growth performance, feeding efficiency, survival, deformities, proximate body composition, and muscle growth in Mexican pike silverside (Chirostoma estor: Atherinopsidae) a short-intestine agastric fish. Fish with an average weight of 180.57 ± 3.02 mg were randomly distributed in twelve tanks and fed four (M4), eight (M8), and twelve (M12) times a day until apparent satiety for 45 days. Significantly higher growth (70%) was found in M12 treatment compared to M4. There was no difference in survival among treatments. However, significantly fewer deformities were found in the M12 treatment compared to M8 and M4 treatments. Increased feeding frequency produced fish with higher lipids, with a concomitant reduction in ash content. Muscle fiber diameters were significantly different in all treatments: M12 (32.97 ± 3.13 μm), M8 (30.28 ± 4.59 μm), and M4 (26.74 ± 4. 42 μm). These results reflect the importance of feeding strategies in accordance to fish habits and their digestive configurations and may be relevant for other emerging species with similar digestive morphology and lower in the trophic chain, which are essential for aquaculture diversification and sustainability.

Influence of dry coal deshaling by pneumatic vibrating FGX separator on steam gasification of coal

Dry deshaling is a modern technique of enhancing coal quality and is considered more ecological and economical than traditional washing processes. Dry deshaling results in an increase in calorific value of coal, removal of ecotoxic elements and generation of usable by-products. At the same time, as a result of the deshaling, the components catalysing the gasification process are also removed. Therefore, the effect of this operation on gasification is uncertain. This study aimed to assess the effect of dry deshaling as performed by a pneumatic vibrating FGX separator on the steam gasification of coals. Two coals were subjected to dry deshaling with various efficiency of minerals removal (pre-improvement of coal quality, and deep enrichment to receive high-quality clean coal). Parents coals and corresponding clean coals were characterised and subjected to gasification measurements at 800, 900 and 1000 °C and the pressure of 1 MPa, using the thermovolumetric method based on an analysis of the composition of the resulting gas. The obtained results showed that reduction of ash content by dry deshaling was accompanied by an increase in carbon content, caloric value and change in ash composition (decreased content of SiO2 while increasing the content of numerous catalytically active oxides, such as Na2O, CaO, MgO and Fe2O3), and these changes were the greater, the deeper the deshaling was. Moreover, the deshaling operation positively affects the gasification process - formation rates of CO and H2 during char gasification, reactivity indicators, and yields of CO and H2 were improved. However, this positive effect was the more remarkable, the less ash was in the analysed sample. This indicates that the removal of minerals facilitated the access of the gasifying agent to the char surface, thus increasing the efficiency of the carbon-steam reaction. In turn, the effect of dry deshaling on calculated kinetic parameters was ambiguous, probably due to the complex mechanism of gasification reactions. Nevertheless, the obtained results show that FGX technology may be an attractive way of preparing coal for gasification. However, deep enrichment is necessary to substantially improve the steam gasification of coal.

Hydrothermal treatment (HTT) for improving the fuel properties of biomass residues

Water leaching and hydrothermal carbonization are tools to upgrade biomass residues for combustion. Water leaching reduces the ash content, which increases the heating value, while hydrothermal carbonization (HTC) increases heating value and ash content and decreases the organic fraction of the fuel. The objective of this study is to investigate, whether low temperature hydrothermal treatment (HTT) of biomass residues can combine the positive aspects of both treatments and avoid the negative aspects: a decrease of the ash content (leaching) instead of an increase (HTC) and a strong increase of the heating value by deoxygenation (HTC) instead of a low increase by ash reduction (leaching). Sawdust, conifer bark, black locust bark, green cuttings, and leaves were treated at 150 °C, 170 °C and 185 °C in a batch reactor. The impact of the three treatments on combustion properties, inorganic element reduction, and organic compound formation in the liquid phase were investigated. All biomass residues, except sawdust treated at 150 °C, showed increased heating values and reduced ash contents. The intensity of the heating value increases, and the reduction rates of selected ash elements were discussed, including a comparison of literature values and a short review on organic reaction and formation processes at low temperature and pressure conditions.

Ways of disposal of objective fuel sediments for fuel

Accumulated sludge from sewage treatment plants in large cities is obsolete, due to which they have lost the vast majority of nutrients, become too mineralized and practically unsuitable for direct use as fertilizer.The research is devoted to the development of a unified approach to the efficient processing of sludge as a fuel with the addition of flammable fillers such as milling peat, buckwheat husk, wood waste (sawdust).Identified factors influencing the energy efficiency of the processes of preparation of raw materials, drying and granulation of composite mixtures based on peat, obsolete sludge and biomass, which allowed to obtain quality pellets and briquettes.The problem of processing obsolete sludge is the low content of organic matter, excessive ash content and high humidity, so they are not suitable for incineration in its pure form and for agriculture. To reduce ash content, it is advisable to add biomass and peat to sludge and dry to reduce moisture.The article presents studies of drying kinetics of composite granules based on peat, obsolete sludge and biomass on an experimental convective drying stand. The convective drying stand allows to carry out heat treatment of composite granules at a temperature of drying agent of 30–150°C and speed of movement of 0,5–5 m/s. A comparison of the drying time of the sludge-peat composition and its components is performed, which shows that during the drying of the composite granules the intensification of the drying process is observed.The presented comparison of drying kinetics of two- and three-component granules shows the same nature of the drying curves and the drying time is in the range of 17–18 minutes. The optimal ratio of components for quality granulation is selected. Effective drying regimes of composite granules based on sludge, peat and biomass are determined. Equilibrium humidity of composite granules not exceeding standard fuel humidity is determined.

Effect of hydrothermal treatment on deep dewatering of digested sludge: Further understanding the role of lignocellulosic biomass

In this study, lignocellulose-assisted hydrothermal treatment (HTT) of digestated sludge was studied to further understand the role of biomass in HTT and its effect on subsequent sludge dewatering. HTT of sludge-biomass mixtures at 180 °C for 60 min at a sludge/biomass total solids (TS) ratio of 1:1 led to solid residue moistures of 36%–40% after dewatering using a hydraulic press at 24 MPa, compared to 69.5% without biomass. Further investigation showed that organic acids, especially acetic acid generated from lignocellulosic biomass hydrolysed extracellular polymeric substances (EPS), especially EPS-protein, and improved sludge dewaterability. The role of organic acids was further verified with the addition of 10.0 g/L acetic acid for HTT of sludge at 180 °C in the absence of biomass. It was also observed that in HTT of sludge with 10.0 g/L acetic acid, protein nitrogen was converted to more stable forms of nitrogen such as pyrrole‑nitrogen and quaternary‑nitrogen. However, HTT with acetic acid alone resulted in dewatered solids with high ash contents, which may limit their applications as soil amendments. Combination of biomass and acetic acid with a sludge/biomass TS ratio of 3:1 and acetic acid loading of 10.0 g/L at a HTT temperature of 180 °C for 60 min led to solid moistures of 50.5% with hardwood sawdust and 57.7% with sugarcane bagasse after dewatering at 3 MPa, corresponding to total weight reductions of 66.3% and 55.7%, respectively. In contrast, HTT of sludge at 180 °C for 60 min without acetic acid and biomass resulted in a solid moisture of 76.6% after dewatering at 3 MPa and a corresponding weight reduction of 49.5%. With the use of biomass and acetic acid in HTT, the treated and dewatered solids also had increased carbon content and reduced ash content. These dewatered solids may be used as potential soil amendments though the properties related to soil applications need to be considered in future studies.

Fatty Acid Profile of Microalgal Oils as a Criterion for Selection of the Best Feedstock for Biodiesel Production

Microalgae are considered to be potentially attractive feedstocks for biodiesel production, mainly due to their fast growth rate and high oil content accumulated in their cells. In this study, the suitability for biofuel production was tested for Chlorella vulgaris, Chlorella fusca, Oocystis submarina, and Monoraphidium strain. The effect of nutrient limitation on microalgae biomass growth, lipid accumulation, ash content, fatty acid profile, and selected physico-chemical parameters of algal biodiesel were analysed. The study was carried out in vertical tubular photobioreactors of 100 L capacity. The highest biomass content at 100% medium dose was found for Monoraphidium 525 ± 29 mg·L−1. A 50% reduction of nutrients in the culture medium decreased the biomass content by 23% for O. submarina, 19% for Monoraphidium, 13% for C. vulgaris and 9% for C. fusca strain. Nutrient limitation increased lipid production and reduced ash content in microalgal cells. The highest values were observed for Oocystis submarina, with a 90% increase in lipids and a 45% decrease in ash content in the biomass under stress conditions. The fatty acid profile of particular microalgae strains was dominated by palmitic, oleic, linoleic, and linoleic acids. Nutrient stress increased the amount of saturated and unsaturated fatty acids affecting the quality of biodiesel, but this was determined by the type of strain.

Chlorine and ash removal from salt-laden woody biomass by washing and pressing

Over 11 million cubic meters of timber were harvested from the coastal forests of British Columbia in 2017. For transport, the logs are usually floated in the water and towed along the coastal waters along Fraser River to sawmills. The submerged timber's chlorine content is up to 100 times higher than the timber harvested from inland. The sawmill residues leftover from cutting the salt-laden timber are unsuitable to be burned in boilers. In this study, ground sawdust, bark, and wood chips of three species: Douglas fir, hemlock, and western red cedar from the Lower Mainland, as well as spruce-pine-fir (SPF) from Vancouver Island, were washed for 5 min using tap water under constant stirring and pressed on a flat metal bed for 30 s using a mechanical hydraulic press. The chlorine content dropped from 2,000–24,000 ppm to below 700 ppm db (dry basis). The low salt biomass meets the ISO 17225-2 quality standard for wood pellets. The chlorine removal efficiency of this treatment method was 88–95%. The reduction in ash content of the washed and pressed samples ranged was 45–85% of the ash in the untreated biomass.

Conversion of aqueous extracts from thermochemical treatment of bagasse into functional emulsifiers

SummarySynthetic emulsifiers in food industries are being replaced with a customer‐friendly food ingredient that is derived from biomass using sustainable green technologies. After hydrothermal liquefaction treatment, raw bagasse (21%), pith (26%), and rind portions (25%) were obtained with reduced ash contents. As aqueous extracts, with oligosaccharides and lignin residues, it was used in the preparation of oil‐in‐water emulsions with 5% soybean oil. Results showed that the emulsions stabilised the oil droplets with particle size between 11 and 17 µm by steric repulsion with raw bagasse‐stabilised emulsion showing a better stability at 25 °C (31 days). It was demonstrated that raw bagasse extracts, without alteration, maybe a potential unconventional source for food‐grade emulsifiers by integrating a versatile thermochemical conversion of waste without the use of chemicals.

Properties and microstructures of a matrix graphite for fuel elements of pebble-bed reactors after hightemperature purification at different temperatures

The matrix graphite (MG) of pebble fuel elements for a High Temperature Gas-cooled Reactor (HTGR), composed of 71wt% natural graphite, 18 wt% artificial graphite and 11 wt% phenolic resin-derived carbon, was purified by high temperature treatment (HTT), and its properties and microstructure were analyzed to investigate the effect of different HTT temperatures and optimize the purification temperature. Results showed that with increasing HTT temperature, its density and thermal conductivity gradually increased, but pore size and d002 gradually decreased. The rate of erosion caused by friction as the fuel pebbles move in the reactor also decreased. The ash content decreased significantly from to 18.2×10−6to 12.3×10−6 after HTT at 1600 °C, but changed little when the HTT temperature was further increased to 1900 °C, especially for catalytic metals such as Fe, Ni and Ca that are related to its corrosion rate. The microstructure improvement and ash content reduction at high temperatures jointly contributed to the increase in the anti-corrosion performance of MG. Based on properties such as crushing strength, erosion resistance, and corrosion rate, a HTT of 1600 °C is adequate although the MG gradually became more ordered with a further increase of HTT temperature from 1600 to 1900 °C. This determination of an appropriate HTT temperature for the production of MG for the fuel elements of an HTGR should improve the production efficiency and reduce the mass production cost of this material for a commercial HTGR.

Torrefaction and Pelleting of Wheat and Barley Straw for Biofuel and Energy Applications

Microwave (MW)-assisted torrefaction and pelleting could enhance biomass fuel properties and energy applications. Plastic wastes are considered as a replacement source binder in pellets to minimize their effect on the environment as pollutants. High-density polyethylene (HDPE), an extractable plastic from recycling waste, was investigated as a binder for torrefied wheat and barley straw pellets. Fuel pellet characteristics, such as durability, density, tensile strength, and water absorption, were used to evaluate the pellets produced from a single pelleting test. The results showed that the addition of HDPE as a binder significantly increased the pellet quality in terms of density (686.12–982.93 kg/m3), tensile strength (3.68 and 4.53 MPa) for wheat and barley straw, and reduced ash content of the pellet from 10.34 to 4.59% for barley straw pellet and 10.66 to 3.88% for wheat straw pellets. The higher heating value (HHV) increased with increasing biochar mix and HDPE binder blend. The highest HHV value observed for barley straw was 28.34 MJ/kg, while wheat straw was 29.78 MJ/kg. The study further indicated that MW torrefaction of biomass-biochar mix with HDPE binder reduced the moisture adsorption of wheat and barley straw pellets, which can significantly improve their storage capability in humid locations. The moisture uptake ratio for MW-torrefied barley straw pellets was 0.10–0.25 and wheat straw pellets 0.11–0.25 against a moisture uptake ratio of 1.0 for untreated biomass. MW torrefaction of wheat and barley straw with biochar and HDPE binder addition during pelleting is a promising technique to improve biomass fuel pellet properties.