نوع مقاله : کاربردی

نویسندگان

• سید رضا طباطبایی کلور ¹
• شعبان قوامی جولندان ²

¹ دانشیار گروه مهندسی بیوسیستم، دانشگاه علوم کشاورزی و منابع طبیعی ساری

² استادیار گروه مهندسی بیوسیستم، دانشگاه شهید چمران اهواز، اهواز، ایران

چکیده

پلت‌های سوختی یکی از موارد استفاده از انرژی زیست‌توده‌ها می‌باشند که از پسماند کشاورزی، بقایای گیاهان و فضولات حیوانات ساخته شده و سبب تولید انرژی بیشتر در واحد حجم می‌شوند. عوامل مختلفی در فرآیند پلت سازی موثر هستند که شناخت آنها به بهینه سازی فرایند پلت سازی و شناخت مکانیزم فشردن و طراحی تجهیزات متراکم کننده کمک می کند. در این پژوهش، از یک دستگاه تک پلت ساز برای ساخت پلت هایی از پسماند کارخانه روغن کشی زیتون استفاده شد و تاثیر تیمارهای اندازه ذرات (600-900، 900-1200 و 1200-1500 میکرومتر)، فشار تراکم (75، 150 و 225 مگاپاسکال) و دما (50، 70 و 90 درجه سلسیوس) بر چگالی، مقاومت و پایداری پلت بررسی شد. نتایج نشان داد که اثرات اصلی هر سه تیمار مذکور بر مقاومت، چگالی و پایداری پلت معنی دار است. همچنین اثرات متقابل برخی تیمارها نیز بر این خصوصیات معنی دار است. بیشترین مقاومت پلت در ترکیب اندازه ذرات 900-1200 میکرومتر، دمای 90 درجه سلسیوس و فشار تراکم 225 مگاپاسکال بدست آمد. بیشترین چگالی در اندازه ذرات 600-900 و فشار تراکم 225 مگاپاسکال و بهترین پایداری در فشار تراکم 150 مگاپاسکال و دمای 90 درجه سلسیوس بدست آمد. بطور کلی خصوصیات فیزیکی و مکانیکی پلت تحت تاثیر هر سه عامل اندازه ذرات، دما و فشار تراکم قرار گرفت.

کلیدواژه‌ها

• زیست توده زیتون
• چگالی
• مقاومت فشاری
• پایداری
• پلت

موضوعات

• تکنولوژی پس از برداشت

عنوان مقاله [English]

Investigating factors affecting the density, strength and durability of pellets made from olive processing plant waste

نویسندگان [English]

• Reza Tabatabaeekoloor ¹
• shaban ghavami jolandan ²

¹ Associate Professor, Department of Biosystems Engineering, Sari Agricultural Sciences and Natural Resources University

² Assistant professor, Department of Biosystems Engineering, Faculty of Agriculture, Shahid Chamran University of Ahvaz, Ahvaz, Iran

چکیده [English]

Introduction Fuel pellets are one of the uses of biomass, which are made from agricultural waste, plant residue, and animal excrement. They produce more energy per unit volume. Various factors are effective in the pelleting process. Having information about them helps to optimize the pelleting process and to understand the compression mechanism and the design of compacting equipment.

Materials and Methods Olive pomace raw material for making pellets was obtained from an olive processing factory in Rudbar city in Gilan province. The prepared materials were transferred to the laboratory in the necessary amount in nylon bags and dried in the oven at 105 degrees Celsius for 24 hours. The dried samples were powdered by a laboratory grinder and then passed through sieves in the range of 0.6-1.5 mm and used to make pellets. Before making pellets, the initial moisture content of the samples was obtained using the drying method. First, pre-tests were conducted to make pellets and the moldability and strength of the samples were checked. A palletization mechanism was used to compress the pellet. This system was designed and built in biosystem mechanics of Sari University of Agricultural Sciences and Natural Resources. The material was placed inside a steel mold with a cylinder inner diameter of 8.05 mm and a height of 150 mm with a blocked end. A piston with a diameter of 8 mm connected to the driving arm of the tension-compression test machine was used to compress the material. Loading by a piston with a quasi-static speed of 6 mm per minute is compressed. In this research, the effect of particle size treatments (600-900, 900-1200 and 1200-1500 μm), compaction pressure (75, 150 and 225 MPa) and temperature (50, 70 and 90 ͦC) on the density, strength and durability of the pellet were investigated.

Results and Discussion The results indicated that the main effects of all three mentioned treatments on the strength, density and durability of the pellet are significant. Also, the mutual effects of some treatments are also significant on these characteristics. The interaction effect of particle size and compaction pressure on pellet compressive strength is significant at 5% level. With the increase in particle size, the pellet strength increased first, and then with the further increase in particle size, the pellet strength decreased slightly. On the other hand, with the increase in compression pressure, the pellet resistance increased. Pellet density is an important factor for storage and transportation as well as combustion efficiency. The mutual effect of compression pressure and particle size on pellet density is significant. Changes in pellet density were obtained in the range of 1.015 to 1.350 grams per cubic centimeter. The usual and recommended density for pellets made from agricultural and forest residues should be more than 0.8 grams per cubic centimeter. The interaction effect of compaction pressure and temperature on pellet durability is significant. The range of durability changes for pellets is between 81 and 95 percent. Increasing compaction pressure significantly improved the stability of the pellets, which indicates the role of compaction in bonding between particles and creating bridges for greater particle strength. The highest pellet strength was obtained in the combination of particle size of 900-1200 micrometers, temperature of 90 degrees Celsius and compaction pressure of 225 MPa. The highest density was obtained at a particle size of 600-900 and a compression pressure of 225 MPa and the best stability at a compression pressure of 150 MPa and a temperature of 90 degrees Celsius. In general, the physical and mechanical properties of the pellet were affected by all three factors: particle size, temperature and compaction pressure.

Conclusion The results of this research showed that all three factors of particle size, compaction pressure and temperature have a significant effect on the physical and mechanical properties of pellets such as density, strength and durability. Choosing the right particle size plays an important role in making the pellet stronger. The temperature of the die during pelleting is also very important in the bonding of the pellet particles because at the right temperature, the bonding between the bridges strengthens the connection of the particles and as a result increases the strength and durability of the pellet. In general, the results of the research showed that to make pellets from olive processing factory waste, a suitable combination of particle size parameters, compaction pressure and die temperature is needed to make pellets with high strength and durability.

کلیدواژه‌ها [English]

• Olive biomass
• density
• pressure strength
• durability
• pellet