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Description
Basis for this thesis is solar research at San Diego State University (SDSU) provided at the Combustion and Solar Energy Laboratory (CSEL). The ultimate goal is to improve energy efficiency within a concentrated solar power system (CSP). Improvements are based on carbon particle production to more effectively absorb solar irradiation. The premise of this thesis is to study the formation of carbon black particles through pyrolysis of hydrocarbons. Focus will be on the production of the particles and improvements of previous CSEL studies. A SDSU lab scale setup is used for carbon particle studies and is primarily focused on carbon particle generation. Particles are generated by a carbon particle generator (CPG) onsite at SDSU. The previous CPG had a length of 60 centimeters while the studied model has a length of 182 centimeters. The vessel is 30 centimeters in diameter with two alumina tubes along the length. The tubes are heated to around 1200 degrees Celsius and pressurized to about 5 bar. A longer CPG vessel is desired to obtain an isothermal temperature profile which did not exist in the previous model. Thermocouples are located along the length to measure the temperature throughout. This environment for the fluid will help create conditions for pyrolysis to produce carbon particles. After production, particle data is measured from the outlet of the CPG. Downstream from the outlet there is an extinction tube to measure the amount of particles in the air stream leaving the CPG. This is monitored for the various gas flows used to observe alterations in production. Scanning electron microscopy (SEM) samples are also taken after the extinction tube to observe sizes. The ideal particle size will range from 200 - 500 nanometers. Computer modeling of the CPG was done to simulate interactions and compare experimental data. ANSYS Fluent was used to create a 2D axisymmetric model to display the temperature field. CHEMKIN-PRO was also used to simulate chemical interactions during pyrolysis of the hydrocarbon. The data gathered experimentally from the CPG is compared to the aforementioned computer models for heat transfer and particle production.
