چكيده به لاتين
The Heavy fuel Oil (HFO) is actually the remaining part of crude oil distillation after the separation of lighter hydrocarbons. The main problem with the combustion of heavy fuel oil is the production of various pollutants such as smoke, residue, ash, soot, and sulfuric acid. However, due to its high calorific value and cost-effectiveness, it holds significant importance. The combustion of HFO produces two types of suspended particles: soot and carbonaceous coke particles (cenosphere). The cenosphere refers to solid particles remaining from the liquid phase pyrolysis, which have a hollow spherical shell shape.
Therefore, considering the importance of the topic, a thesis titled " Cenosphere Formation Modeling of Heavy Fuel oil droplet Combustion" has been defined. This thesis has addressed the research and development of the subject in four stages. In the first step, a laboratory study was conducted on the heating of heavy fuel oil droplets from a low temperature of 400℃ to the ignition temperature of 800℃. This study led to the temperature behavior and droplet diameter, as well as the identification of various types of solid particles and their formation. It was observed that a total of four types of solid particles remain from heavy fuel oil. In the second step, a theoretical model of residue ash formation (the fourth type of particle) was developed assuming a single droplet and in a phase of development. In this model, by solving the energy equation in the liquid phase, the Spalding evaporation equation, and the optimized kinetic model equations, a suitable prediction of the changes in droplet diameter, diameter, thickness, and mass of residue ash was obtained. In this model, the effects of changes in ambient temperature, initial droplet diameter, and addition of light fuel were considered. This modeling showed that for further model development and accuracy improvement, a precise and fuel-specific kinetic reaction model is needed. Therefore, in the third research step, a kinetic reaction modeling based on the results of Thermogravimetric Analysis (TGA) tests was presented. This study led to the mass behavior of fuel during heating and the presentation of two types of bulk and pseudo-particle models consistent with experimental results. In the fourth and final step, a modeling of solid particle formation from the pyrolysis of heavy fuel oil at different temperatures was presented. This model was developed based on three theoretical models: a two-phase pseudo-particle evaporation model, a pseudo-particle kinetic reaction model (developed from the third step), and a temperature-dependent shell formation model (presented in this stage). In this model, the effects of temperature variations and initial droplet diameter on the formed particles and fuel pyrolysis were investigated.
