احمد آذری

The purpose of this study was to study the calculation of fluid dynamics in order to modify the De-Coking method. ANSYS Fluent v16.2 commercial software was used in this study and also for modeling of the furnace which was studied was used Design Modeler software and then computing grid was created by using The ANSYS Meshing. It then examined the independence of the grid. Furnace modeling was carried out in two parts, without coke injection (operating conditions) and with coke injection (conditions studied), in this study the k-? Realizable, Discrete Ordinate, Non-Premixed, and DPM were used to simulate flow turbulence, radiation heat transfer, combustion and coke particles flow respectively. The purpose of the first part (without coke injection) was to evaluate the results with industrial results. In the second section, the flow rate of the coke output from the furnace coils, which had a large amount of steam, was directly injected into the furnace combustion chamber, and the simulation was carried out, the results showed that the conversion of the coke was about 52 Percent, meaning that a lot of coke particles enter into the atmosphere. In the next step, four solutions to this problem were presented, and each was studied. 1. Change in the percentage of excess air 2. Increase fuel flow to the burners 3. Increase de-coke stream temperature 4. Coke injection with dry air flow. The solution number (1) showed that by changing the percentage of excess air, the percent conversion can be increased by 55%, solution number (2) showed that increasing the fuel flow rate increases the percentage of conversion of coke particles to 66 %. The solution number (3) showed that raising the De-Coke flow temperature before entering the combustion chamber would be able to bring the conversion rate to 55%. Finally, the solution number (4), which was the best possible solution, could convert the percentage of coke particles to 100%, and the particles of coke injected into the furnace, con