Design and numerical validation of a mild combustor to reduce the soot formation at partial oxidation of natural gas

Increasing energy demand and public awareness on the environment causes energy supplying companies to search for alternative and more cleaner fuels. These companies are seeking for more efficient and environmental use of the current fossil fuel supply, since a direct shift towards renewable energy is not economical feasible. One of these solutions is the partial oxidation of natural gas, which is a by-product of oil drilling. The product of this process is syngas, which can transformed into synthetic products, like synthetic fuels.

The problem with this process is the large amount of soot formed during the oxidation process. It requires a lot of energy and space to remove the soot and clean the syngas. The ULRICO-project was therefor started to investigate the formation of soot and different operating conditions. The formation of soot is analyzed by determining the soot particle size distribution and concentration. The goal of the ULRICO-project is to reduce the formation of soot, while maximizing the syngas output, by finding the optimum operating conditions and by implementing the mild combustion mechanism into the partial oxidation process.

The goal of this graduation project was to design, validate and build a combustor, which preheat and dilute the reactant to start a mild combustion process. The designed combustor was numerical simulated and analyzed with the CHEMKIN PSR and ANSYS CFX-13. These simulations have shown that the formation of acetylene, a soot precursor, was reduced and that the output of syngas was improved. All parts of the mild combustor setup have been manufactured and are ready for assembly. Experiments were performed with the current premixed swirled combustor, of which the data was parameterized. The results of these experiments are used to improve the quality of the CFD soot-model.