Full conversion method and device for producing light aromatic hydrocarbons from light cycle oil

A process of producing light aromatics from light cycle oil;

• comprising the steps of:
• 1) feeding LCO into a first reaction zone for hydrofining, to provide a first stream:
• wherein the reaction conditions for the first reaction zone comprise:
• a volume ratio of hydrogen to oil of 500-3000 Nm3/m3;
• or an inlet temperature of a reactor of the first reaction zone of 280-420° C.;
• or a partial pressure of hydrogen of 5-10 MPa;
• or a space velocity of 0.5-2.0 h−1;
• or a combination thereof;
• 2) feeding the first stream to a second reaction zone for selective conversion to perform hydrocracking with the proviso of retaining one aromatic ring of the polycyclic aromatic hydrocarbons in the heavy aromatics of the first stream, and simultaneously enable the isomerization and cracking of the macromolecular non-aromatic hydrocarbons of the first stream, to provide a second stream, wherein the first stream is optionally subjected to impurity separation in a second separation zone to remove impurities selected from hydrogen sulfide and ammonia before being fed to the second reaction zone;
• 3) subjecting the second stream to a first separation in a first separation zone, to provide a third stream comprising C10+ heavy aromatics at a bottom of the first separation zone comprising a gas-liquid separator and a rectifying column;
• 4) feeding the third stream to a post-saturation selective reaction zone for hydrogenation saturation of C10+ heavy aromatics, to provide a fourth stream comprising a product having one benzene ring, wherein the reaction conditions for the post-saturation selective reaction zone comprise:
• a volume ratio of hydrogen to oil of 200-3000 Nm3/m3;
• or an inlet temperature of reactor of the post-saturation selective reaction zone of 100-280° C.;
• or a partial pressure of hydrogen of 1.0-4.0 MPa;
• or a space velocity of 0.1-5.0 h−1;
• or a combination thereof;
• 5) recycling the fourth stream to the second reaction zone, wherein the reaction conditions for the second reaction zone comprise:
• a volume ratio of hydrogen to oil of 800-5000 Nm3/m3;
• or an inlet temperature of reactor of the second reaction zone of 280-450° C.;
• or a partial pressure of hydrogen of 5-10 MPa;
• or a space velocity of 0.5-2.0 h−1;
• or a combination thereof.