The Joint Removal Technology For SO_x And NO_x From Petrolchemical Flue Gas

The chemical elements in petroleum are mainly five elements such as carbon, hydrogen, sulfur, nitrogen and oxygen. Sulfur and nitrogen are non-hydrocarbon components, their oxides are emitted into the atmosphere in the process of petroleum refining result in environmental pollution.The pollution level from petrochemical smoke related to sulfur and nitrogen content in the crude oil, where sulfur and nitrogen exist as form hydrocarbon compounds instead of elemental form. The sulfide from oil processing are mainly sulfur dioxide, hydrogen sulfide and mercaptan, and they will accelerate the corrosion to refining unit and increase the pollution risk from emission if sulfur content is high. In the existing technology for flue gas purification, desulfurization and denitrification is commonly done by each independent system, respectively. At present, the most method of desulfurization to flue gas is limestone/lime, ammonia, sodium and magnesium desulfurization and so on. The nitrogen oxides from petrochemical flue gas are one of the main sources contribution nitrogen oxides to the atmosphere. The present technology to reduce NOx emission mainly includes what flue gas circulation, the low NOx burner, selective catalytic reduction, and selective non catalytic reduction and so on.However, the desulfurization and the denitrification were done, respectively, not only occupy large area of land, but also need the high cost of investment and running. In order to reduce the cost of flue gas purification and to meet the development needs of petrochemical enterprise, adopting joint removal technology to desulphurization and denitrification for flue gas purification has become the inevitable trend. Joint removal technology for sulfur and nitrogen oxides becomes a new technology base on desulfurization and denitrification of flue gas. As same as flue gas desulfurization technology, joint desulphurization and denitrification is also divided into wet and semi-dry and dry method.Because of petrochemical each enterprise has the difference of refining process, its way of desulphurization and denitrification is also different. In a northeast petrochemical company case, the emission concentrations of sulfur and nitrogen oxides in flue gas were lower than control standards during refining the crude oil with low sulfur and low nitrogen, save the economic cost of desulphurization and denitrification. But the emission concentrations of sulfur and nitrogen oxides in flue gas were more than control standards during refining the crude oil with high sulfur and high nitrogen. Thus, Adopt the joint technology of desulphurization and denitrification for this petrochemical company is an important issue, and a process of activated carbon or SNOX (WSA-SNOX) was proposed in this paper.