| Nitrogen oxides, as the conventional substance which lead to the air pollution inenvironmental science, are included as binding characters and controlled for theirtotal emission amount since the beginning of the12th Five-Year Plan. From2011,environmental departments across the country had calculated and control the totalamount of nitrogen oxides in the area under their administration, which meansnitrogen oxides are formally being brought up on the agendahas by the. Government.Nitrogen oxides are the main emissions in oil refinery factories. There are variouscontrolling methods used in different countries, some directly specify the industrycontrol standard, while others may emphasis on fuel combustion standards, whereas indomestic markets, things are not going well due to historical problems. In currentdomestic oil refining industry, besides control policy in some individual areas, there isno official emission controlling standard.Nitrogen oxides only exist in kinds of combustion gases, including heating furnacegas, catalytic burning gas, boiler gas and incinerated gas from tail gas of sulfur. indomestic oil refining factories now, regenerated flue gas from catalytic cracking unitand nitrogen oxides discharged from power boiler have already took up a largeproportion in the total nitrogen oxides emission amount, others are nitrogen oxidesgenerated from types of heating furnace gas.At present in the oil refining industry, the emission reduction work in domestic oilrefining industry still stays on single-point strategy, only making efforts to meet therequirement of nitrogen oxides emission reduction and carrying end treatment toexhaust gas. There is no overall and systematic reduction plan. Their works are simplyto maintain the current status but lack of the awareness to reduce emission on their owninitiative.Reducing the emission of nitrogen oxides in oil refinery is a systematicengineering, from beginning to the end it should have an overall plan of reducing theemission, then it can be implemented step by step. Firstly, it is necessary to control fromthe beginning, for the raw materials of FCC it should be hydrotreated to reduce thecontent of nitrogen, so as to reduce the nitrogen oxides in regenerated flue gas of FCC.Secondly, add the measure of low nitrogen combustion to the heating furnace in oilrefinery step by step to reduce the emission of nitrogen oxides in the heating furnace. Thirdly, replace the traditional power boilers by IGCC, to reduce the emission ofnitrogen oxides in power systems in oil refinery significantly. Finally add the measure toremove the nitrogen oxides in the flue gas of boilers and the regenerated flue gas ofFCC, In order to reduce the emission of nitrogen oxides in the whole oil refinery further. |
