نوع مقاله : مقاله پژوهشی
نویسندگان
1 گروه فنی کشاورزی، دانشکده فناوری کشاورزی، دانشگاه تهران
2 هیات علمی، گروه فنی کشاورزی، پردیس ابوریحان، دانشگاه تهران، تهران، ایران
3 گروه فنی کشاورزی، دانشکده فناوری کشاورزی، دانشگاه تهران، پاکدشت، ایران
چکیده
کلیدواژه‌ها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
Conversion of biomass resources such as agricultural residues can enhance the energy supply and improve the diversify of the energy portfolio. One of the primary methods for preparing solid fuel for energy uses involves densifying shredded residues, a process known as briquetting. This study investigated the modeling of ozone pretreatment and its impacts on the production of bagasse fuel briquettes, utilizing a hydraulic press and employing response surface methodology (RSM). The effect of independent variables including the particle size of bagasse (≤1.18, 1.18-2.36, and 2.36-4.75 mm), brequetting temperature (280, 320, and 360 °C), moisture content of bagasse during ozonation (20, 35, and 50%), and ozonation time (15, 25, and 35 min.) was evaluated on on the physical, mechanical, and chemical properties of the briquettes. The results indicated that the moisture content of bagasse played a significant role in the ozonation pretreatment. Increasing the moisture content during the ozonation process to approximately 30% enhanced the toughness of the produced briquettes; however, further increasing it to 50% resulted in a decrease in toughness. The calorific value of the briquettes was calculated using validated experimental equations based on the results of proximate analysis. Findings revealed that ozone pretreatment boosts the calorific value of the briquettes compared to those without pretreatment. The optimal conditions for briquette production were identified as 15 minutes of ozonation, a bagasse particle size smaller than 1.18 mm, a moisture content of 33.448%, and a briquetting temperature of 280 °C. The optimum briquette density and toughness were found to be 982.310 kg/m³ and 249.934 kPa, respectively. Overall, ozonation pretreatment significantly enhanced the properties of sugarcane bagasse fuel briquettes.
کلیدواژه‌ها [English]
Effect of ozone pretreatment and densification parameters on the physical, mechanical, and fuel characteristics of bagasse briquettes
EXTENDED ABSTRACT
Among renewable energy resources, biomass has the potential to serve as a sustainable alternative to fossil fuels. However, the significant distance between the source of biomass and its point of use results in high transportation costs due to factors such as high moisture content, irregular shapes, and low density. Additionally, the direct combustion of biomass presents challenges related to its high moisture content, low volumetric density, and limited energy potential. These issues can be mitigated through densification into briquettes, a process that produces a solid and dense fuel with consistent properties. To enhance the physical, chemical, and thermal characteristics of lignocellulosic biomass for biofuel production, pretreatment is often necessary. Ozone, being a powerful oxidant, can be utilized for biomass pretreatment due to its ability to cleave carbon-carbon double and triple bonds, such as those found in lignin. This study aims to examine the effects of various ozonation pretreatment variables and the densification process on the quality of briquettes while also assessing their physical, mechanical, and chemical properties.
The sugarcane bagasse used in this study was provided by Haft Tappeh Sugarcane Agro-Industry Co., located in Khuzestan province, Iran. Optimizing the effect of ozonation pretreatment in the production of briquettes was performed using a hydraulic press. The independent variables were the size of bagasse particles (≤1.18, 1.18-2.36, and 2.36-4.75 mm), the mold temperature (280, 320, and 360 °C), the moisture content of bagasse in ozonation reactor (20, 35, and 50% w.b.) and time duration of ozonation (15, 25, and 35 minutes). The dependent variables were the toughness and relaxed density of briquettes. The experiments were designed using the response surface methodology (RSM) based on a central composite design (CCD) in Design Expert v.11 software. The ozonation process was performed in a fixed bed cylindrical reactor made of transparent plexiglas on a laboratory scale. For each treatment, a 6 g bagasse sample was placed in a stainless-steel container inside the reactor. Oxygen concentrator with 93% high purity, and the output ozone concentration was 30 g/h. Based on proximate analysis and measurement of moisture content, volatile matter, ash, and fixed-carbon content have been used to predict the higher calorific value of briquettes through validated experimental equations.
The results showed that by decreasing the particle size, the density of the produced briquettes increased. Ozone pretreatment showed a significant effect on briquette quality, especially density. The maximum value of the briquette density of ozone-pretreated bagasse was 1076 kg/m3, higher than the corresponding amount without pretreatment was 873 kg/m3. The results showed that by increasing the moisture content of bagasse up to 30% in the ozonation process, the toughness of the briquettes increased. After that, the toughness decreased when the moisture content increased to 50%. The ozone pretreatment enhanced the calorific value of bagasse briquettes produced compared to briquettes without pretreatment. The results showed that ozonation pretreatment in the briquette production process increased its calorific value from 16.61 to 17.85 MJ/kg. This issue concerns increasing the percentage of fixed carbon and reducing volatile matter in the ozonation pretreatment process. Previous research has shown that the physical properties of briquettes, including density, affect their calorific value. Generally, the briquettes with a better compression process and higher density will have a higher calorific value. Briquette production was favored at higher values of density and toughness, and at lower values of ozonation time duration and mold temperature. Using the desirability function-based optimization, optimal points with the highest desirability value (≥ 0.8) were determined. At the optimal point, the density and toughness were 982.31 kg/m3 and 249.934 kPa, respectively.
The assessment of the operating parameters of ozone pretreatment in producing fuel briquettes showed that the moisture content and particle size of bagasse had the most effects on the density and toughness of briquettes. Optimum briquette production conditions were determined at 15 minutes of ozonation, bagasse particle size smaller than 1.18 mm, moisture content 33.448% (w.b.) and brequetting temperature 280 °C. The optimal values of briquette density and toughness responses were obtained as 982.310 kg/m3 and 249.934 kPa, respectively. In general, ozone pretreatment improved the properties of sugarcane bagasse fuel briquettes. The calorific value of fuel briquettes produced from ozone-treated bagasse under optimal conditions was 17.85 MJ/kg, while this value was 16.61 MJ/kg for no pretreatment.
Hussain Shafaie: Writing – original draft, Methodology, Data curation, Software, Formal analysis; Ali Mashaallah Kermani: Writing – review and editing, Conceptualization, Supervision, Project administration, Methodology, Visualization, Investigation, Validation; Ehsan Sarlaki: Writing – review and editing, Formal analysis, Investigation, Data curation, Validation, Resources; Mohammad Hossein Kianmehr: Supervision, Project administration, Methodology, Resources.
Data available on request from the authors. All the data used in this original research are presented throughout the text and in the form of Tables and Figures.
The authors avoided from data fabrication and falsification.
The authors extend their sincere appreciation to the University of Tehran for their support throughout this project.
This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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