Thermal and Mechanical Analysis of Rotary Kiln of Activated Carbon Producing Reactor

IntroductionActivated carbon has a wide range of applications as a porous material in the liquid or gas phase adsorption process. The physical process of activated carbon production is divided into two stages thermal decomposition and activation. In this study, only the activation stage has been studied because it is very important in the properties of activated carbon being produced.The production of activated carbon from horticultural waste not only leads to cheap production and supply of many industrial and environmental necessities but also reduces the amount of the produced solid waste. Iran produces about 94,000 tons of pistachio husk annually, which is a good raw material for the production of activated carbon. The profitability index of activated carbon production in Iran is equal to 3.63, which in the case of export, the profitability index will be tripled.Studies have shown that temperature, period, and activation gas flow are the key factors affecting burn-off and iodine number during activated carbon production. Among the various activators tested, steam was found to be the most efficient, with the fastest activation time. For pistachio crops, the minimum iodine number required for economic efficiency is 600 mg g-1, while the highest specific surface area according to the BET test is 1062.2 m2 g-1.Materials and MethodsA Mannesmann tube made of 10 mm thick steel was used to construct the rotating reactor. To minimize heat loss during operation, the kiln body was insulated with a ceramic blanket capable of withstanding temperatures up to 1400°C. The kiln had a length and diameter of 190 cm and 48 cm, respectively, and operated at a temperature of 600°C, requiring approximately 25 kWh of energy for heating. CATIA V5 R21 software was employed to design the device, while ANSYS R20 software was used for thermal and mechanical analysis. The rotary reactor was identified as a critical component due to the high levels of thermal and mechanical stress it experiences. To address these issues, a thermal and fluid analysis was conducted, followed by a mechanical analysis using the results from the prior step. Subsequently, experimental tests were performed on the actual model, and the results were analyzed using statistical methods, including the T-student test in IBM SPSS software.The central heating unit and its surroundings were modeled using ANSYS CFX to obtain valuable information on fluid velocity, radiant properties, and heat transfer within the kiln