Method for processing an inferior gasoline and a system for processing the same

A method for processing an inferior gasoline, comprising the steps of:

• allowing the inferior gasoline to be contacted with a sulfur-transfer catalyst in the presence of hydrogen and undergo a sulfur transfer reaction, and then cutting the gasoline to obtain a light gasoline fraction, a medium gasoline fraction and a heavy gasoline fraction, wherein the gasoline is cut into the light gasoline fraction and the heavy component firstly, and then the heavy component is cut into a medium gasoline fraction and a heavy gasoline fraction;
• mixing the light gasoline fraction with isobutane, wherein olefins in the light gasoline fraction are subjected to an alkylation reaction under the action of a light gasoline alkylation catalyst to obtain an alkylated light gasoline;
• obtaining an olefin-rich raffinate oil and a sulfide- and aromatics-rich extracted oil by separating the medium gasoline fraction by passing the medium gasoline fraction through an extractive distillation system;
• mixing a raffinate oil with formic acid, wherein olefins in the raffinate oil are subjected to an esterification reaction under the action of a medium gasoline esterification catalyst, and then an unreacted formic acid is removed to obtain an esterified medium gasoline, or the raffinate oil is not subjected to an esterification reaction and the raffinate oil is directly mixed with product after removing the H2S to carry out a hydrocarbon isomerization/aromatization reaction;
• mixing the heavy gasoline fraction with the extracted oil to obtain a mixed gasoline, wherein the mixed gasoline is successively subjected to a one-stage hydrodesulfurization reaction, a two-stage hydrodesulfurization reaction and H2S-removal and a hydrocarbon isomerization/aromatization reaction to obtain a treated heavy gasoline;
• wherein the one-stage hydrodesulfurization reaction occurs under the condition that the mixed gasoline is contacted with a one-stage selective hydrodesulfurization catalyst to remove macromolecular sulfides;
• wherein the two-stage hydrodesulfurization reaction occurs under the condition that the product of one-stage hydrodesulfurization reaction is contacted with a two-stage selective hydrodesulfurization catalyst to remove the small molecular sulfides;
• wherein the hydrocarbon isomerization/aromatization reaction occurs under the condition that the product of H2S-romoval is contacted with a hydrocarbon isomerization/aromatization catalyst;
• re-blending the alkylated light gasoline, the esterified medium gasoline and the treated heavy gasoline to obtain a clean gasoline, wherein the clean gasoline is a National VI clean gasoline product with sulfur content ≤10 μg·g−1, olefin content ≤15 v %, and benzene content ≤0.8 v %.