Fayez Nasir Al-Rowaili2022-05-182022-05-186045https://drepo.sdl.edu.sa/handle/20.500.14154/1871Today science is concerned with toxic emissions from refineries, such as NOx. This research work is concerned with studying NO x emission from oil refineries. When NOx exists in large amounts, it could cause different types of serious diseases and illnesses like lung and breathing problems to human being and animals. Due to the dangerous effects of NOx on the environment and human health, it becomes essential for science to do deep research in this area, in order to find optimal ways of NOx reduction. The purpose of the study is to find how to reduce NOx emissions from oil refineries using different methods while maintaining profits at the maximum possible value. The three methods being used for NOx reduction are; balancing, fuel switching and use of technology for NOx reduction. I will try to reduce NOx emissions using the above three methods with different reduction percentage ranging from 20% to 80%. The profits of the oil refinery for each reduction target of NOx will be analyzed and looked at closely. As it should be stated in this research work, my goal is to find the optimal profits considering the required NOx reduction percentage through the use of the GAMS software General Algebraic Management System. GAMS will assist in calculating total cost and profits for different cases with different NOx reduction percentages. GAMS, in addition to giving profits values can tell us, among the three NOx reduction methods, which method will be used for each unit of the oil refinery in order to keep the profits at the maximum possible value.enThesis