Sharif Digital Repository

In this project Visbreaker furnace was modeled and optimized. For this goal, Lobo & Evans method and refinery data was used. Effect of parameters such as, excess air, stack height, decoking period, burn out and fuel heat value were investigated. Among optimization method, genetic algorithm and MITA (Musical Instrument Tempering Algorithm) were used to minimizing cost function of furnace. Also based on Zone method, profiles of properties of process fluid were obtained. Finally fuzzy logic was used for furnace behavior identification  

Ethylene process is one of the most complex systems in petrochemical industries.The first section of the ethylene plant is the cracking furnace.The radiant section of predicted olefin furnaces is symmetrical with respect to a plane through the center line of the furnace and at an angle of 90° with the side walls. There are a total of 24 vertical radiant coils located centrally in the firebox wherein, bottom andside wall burners supply the heat necessary. Each four coils known as a ZONE so, as a result there are six zones, called zone A through F. Failures(rapture, creep, material degradation) rate on the coils decreases from zone A to zone F (A, B, C, D, E and F) respectively.From... 

The delayed coking process is one of the common thermal process technique that used to improve the quality of heavy oil. In this process, heavy feeds such as vacuum residues have been heated in the furnace to temperatures up to the 480-500 °C. For the cracking reactions the heated feed have been sent to the drum that is placed after the furnace. Since the reactions begin inside the furnace and coke is one of the products, deposited on the wall of the tube. With the deposition of coke on the tube wall and the reduction of heat transfer, the temperature of the tube have been increased with the increasing of the flame temperature to save constant heat flux. Therefore, the study of thermal... 

Todays, heat recovery steam generator (HRSG) systems are used extensively in combined power plant cycles (consisting of Rankine cycles and Brighton gas cycle) to maximize their efficiencies. The role of HRSG is essential in providing additional energy needed in the steam cycle part. The HRSG has many pipes or harps. They recover the heat from the incoming gas from the gas turbine outlet, which may be boosted up by the duct burner unit. The main challenge in simulating heat recovery units such as tube bundles is to provide ultra-large and cost-efficient grids. In such situations, alternative models are used to simplify the simulation of the steam generator in full scale, including the... 

Using Aspen Hysys to simulate burners and furnaces has been the focus of several studies in recent years. According to the studies and investigations carried out in the field of optimal design of the furnace, heating the air is one of the possible tasks to improve the performance and increase the efficiency. According to the obtained results, by adding air preheat, the efficiency increases from 92% to 96%. Also, to validate the simulation, two furnaces from Sepahan Oil Refinery furnaces were simulated in the field of oil production, which were simulated with an error of less than 1% in duty calculation, and according to the general results obtained, adding air preheat can increase the... 

Deposition of solid particles present in the process air on the walls of furnaces is one of the challenges in industries. This phenomenon has various causes. For example, in a furnace, the temperature of particles increases as they pass in front of the furnace burners, and due to the softening of the particles, their chances of deposition increase when they collide with the walls. Over time, with the growth of deposited particle layers on the combustion chamber walls, the performance of the combustion system gradually becomes impaired. present research aims to design air jets intersecting with the process air path, with the purpose of reducing the temperature of particles prone to deposition...