Reduction of Dust Output from Prilling Tower of Khorasan Petrochemical Company Using Six Sigma Methodology

Urea (NH2CONH2) is very important for the agriculture industry as a nitrogen-rich fertilizer. Urea synthesizes from ammonia (NH3) and carbon dioxide (CO2) at 170 - 180˚C and 143 kg/cm3. This study aims to reduce the amount of urea dust from the flue gas emitted from the Urea Prilling Tower of Khorasan Petrochemical Company. Since the conversion process of molten urea to urea seeds produce much dust, a large amount of environmental pollution caused by this industry can be prevented by examining various factors in dust production in this plant. Thus, the project was divided and implemented into six general phases (Six Sigma project), including problem definition and study phase, measurement and estimation of time and cost required, preliminary analysis, design, and implementation (DMAIC methodology). After implementing the plan, a significant reduction in urea emissions was observed, about 38%. Therefore, the results show that Six Sigma is a useful tool that can accurately predict the removal of urea dust from flue gases.