CN-121991723-A - Process method for selective deep desulfurization and denitrification of aromatic-rich fraction

CN121991723ACN 121991723 ACN121991723 ACN 121991723ACN-121991723-A

Abstract

The invention discloses a process method for selective deep desulfurization and denitrification of aromatic-rich fraction, which comprises the following steps of (1) mixing aromatic-rich diesel oil with hydrogen, then entering a pre-hydrogenation reaction zone I for pre-hydrogenation and dealkenation reaction, (2) entering a product of the step (1) into a hydrofining reaction zone II for hydrofining and desulfurization and denitrification reaction, (3) flash evaporating and separating out recycle hydrogen from the product of the step (2), entering a moving bed adsorption and denitrification reaction zone III for the obtained refined diesel oil, carrying out deep adsorption and denitrification reaction on the refined diesel oil under the action of an adsorption and denitrification agent to obtain a refined aromatic-rich diesel oil component after desulfurization and denitrification, (4) entering an adsorbent regeneration zone IV for inactivating the adsorption and denitrification agent in the step (3), completing reduction of the adsorption and denitrification agent under the action of a desorption agent, and drying to obtain the circularly regenerated adsorption and denitrification agent. The process method can realize the deep removal of the sulfur-containing and nitrogen-containing compounds, and greatly reduces the investment cost.

Inventors

SUN LIMIN
XIANG YONGSHENG
HU XIAOLI
LI YUHANG
CHAI YONGMING
LI RUOYU
LIU BIN
ZHAN XUECHENG
MA HAOWEN
GUO DAJIANG

Assignees

中国石油天然气股份有限公司
中国石油大学(华东)

Dates

Publication Date: 20260508
Application Date: 20241106

Claims (10)

1. The process method for selective deep desulfurization and denitrification of the aromatic-rich fraction is characterized by comprising the following steps of: (1) Mixing the aromatic-rich diesel oil with hydrogen, and then entering a pre-hydrogenation reaction zone I for pre-hydrogenation dealkening reaction; (2) The product obtained in the step (1) enters a hydrofining reaction zone II to carry out hydrofining desulfurization and denitrification reaction; (3) Separating recycle hydrogen from the product obtained in the step (2) by flash evaporation, and enabling the obtained refined diesel oil to enter a moving bed adsorption denitrification reaction zone III, wherein an adsorption denitrification agent is arranged in the adsorption denitrification reaction zone III, and the refined diesel oil is subjected to deep adsorption denitrification reaction under the action of the adsorption denitrification agent to obtain a refined aromatic diesel oil component after desulfurization and denitrification; (4) And (3) introducing the deactivated adsorption and denitrification agent obtained in the step (3) into an adsorbent regeneration zone IV, wherein a desorption agent is arranged in the adsorbent regeneration zone IV, and the deactivated adsorption and denitrification agent is reduced under the action of the desorption agent and dried to obtain the circularly regenerated adsorption and denitrification agent, so that the continuous regeneration of the adsorption and denitrification agent is realized.
2. The process method according to claim 1, wherein in the step (1), the pre-hydrogenation dealkylation reaction is carried out under the conditions of a hydrogen partial pressure of 0.2-4 MPa, a reaction temperature of 50-400 ℃, a hydrogen-oil volume ratio of 100-500 Nm 3 /m 3 and a liquid hourly space velocity of 0.3-3.0 h -1 .
3. The process according to claim 1, wherein in the step (2), the conditions of the hydrofining desulfurization and denitrification reaction are that the hydrogen partial pressure is 0.2-4 MPa, the reaction temperature is 280-400 ℃, the hydrogen-oil volume ratio is 100-500 Nm 3 /m 3 , and the liquid hourly space velocity is 0.3-3.0 h -1 .
4. The process of claim 1, wherein in step (1), a catalyst is added to the pre-hydrodeolefination reaction, the catalyst comprising a support and a supported active metal; The carrier is inorganic refractory oxide, wherein the inorganic refractory oxide is at least one of alumina, amorphous silica-alumina, silicon dioxide and titanium oxide; the active metal is selected from a group VIB metal component or/and a group VIII metal component.
5. The process according to claim 1, characterized in that the group VIB metals comprise tungsten and/or molybdenum, the content of the group VIB metals being 10% -30% by weight of oxides; the VIII group metal comprises nickel and/or cobalt, and the content of the VIII group metal is 1% -8% by weight of oxide.
6. The process of claim 1, wherein in step (2), the hydrofinishing catalyst used in the hydrofinishing desulfurization and denitrification reaction is the same or different than the catalyst used in the pre-hydrodeolefination reaction of step (1).
7. The process method according to claim 1, wherein in the step (3), the condition of the deep adsorption denitrification reaction is that the pressure is 0-1 MPa, the temperature is 30-90 ℃ and the liquid hourly space velocity is 0.1-0.5 h -1 .
8. The process method of claim 1, wherein in the step (3), the adsorption denitrification agent comprises powder, an adhesive and an acid solution, wherein the raw material components of the powder comprise, by weight, 10-30 parts of silicon dioxide, 20-50 parts of aluminum oxide and 20-60 parts of zinc oxide, the raw material components of the adhesive comprise, by weight, 10-90 parts of silica sol and 10-90 parts of alumina sol for adhesion, the acid solution is at least one of sulfuric acid, nitric acid and phosphoric acid, and the acid load is 2-8%.
9. The process method according to claim 1, wherein in the step (4), the desorbing agent is an alcohol solution, the alcohol solution is at least one selected from a methanol solution and an ethanol solution, and the condition that the deactivated adsorption denitrification agent is reduced in the eluting solution is that the pressure is 0-1 MPa, the temperature is 30-90 ℃ and the liquid hourly space velocity is 0.1-2 h -1 ; in the step (4), the drying gas in the drying process is nitrogen or air, and the drying condition is that the volume space velocity flow is 500-5000 h -1 , the temperature is 100-200 ℃, and the pressure is 0-1 MPa.
10. The process according to claim 1, wherein the circularly regenerated adsorbent-denitrifying agent obtained in the step (4) is continuously used as the adsorbent-denitrifying agent for the deep adsorption-denitrification reaction in the adsorption-denitrification reaction zone III of the step (3), wherein the single cycle service life of the adsorbent-denitrifying agent is not less than 15 days.

Description

Process method for selective deep desulfurization and denitrification of aromatic-rich fraction Technical Field The invention relates to an aromatic fraction selective hydrofining process, in particular to a process method for deep desulfurization and denitrification of an aromatic-rich fraction. Background In recent years, the economic structure of China is continuously changed, and China oil refining enterprises are moving from a high-speed development stage to a high-quality development stage. At present, the refining is integrated, and the production process is clean, low-carbonization, intelligent and the like, so that the method becomes a main characteristic of high-quality development of the oil refining industry. However, sulfur-containing compounds such as Thiophene (TH), benzothiophene (benzothiophene), dibenzothiophene (DBT) and the like and nitrogen-containing compounds such as quinoline, pyridine, pyrrole and the like in oil products have high content, and can be converted into SO X and NO X in the combustion process, SO that environmental problems such as acid rain, haze and the like are formed. Meanwhile, the sulfur and nitrogen-containing compounds can reduce the quality of oil products and influence the reaction process, for example, impurities such as sulfur, nitrogen and the like contained in naphthalene-rich fractions such as catalytic diesel oil and the like are poisons of catalysts for subsequent alkylation reactions and the like, so that raw materials are required to be subjected to refining pretreatment before being used in the subsequent reaction process. The nitrogenous compound in the naphthalene-rich fraction raw material has strong inhibition effect on desulfurization reaction, and the naphthalene aromatic hydrocarbon can also generate side reactions such as aromatic ring partial hydrogenation saturation, ring opening and the like during deep desulfurization and denitrification. Therefore, the depth of the raw material hydrodesulfurization nitrogen impurities is increased, the yield of naphthalene aromatic hydrocarbon in the hydrogenation process is ensured, and the development of the hydrofining treatment process with high activity and high selectivity is a technical key. Most of research teams now focus on the hydrodesulfurization and denitrification of aromatic-rich diesel on the preparation of catalysts. Patent CN108236965A discloses a modified hydrodesulfurization catalyst and a preparation method thereof, wherein a nano microcrystalline self-assembly method and an impregnation method are adopted to prepare a citric acid and magnesium double-modified L/Al 2O3 composite carrier, and then a metallic molybdenum and cobalt salt solution is subjected to ultrasonic dispersion to prepare the hydrodesulfurization catalyst. The technology only researches a hydrodesulfurization catalyst of diesel oil, does not explore the process, and does not research the hydrogenation performance of the real oil product. Patent CN116590047a discloses a process system and a production method for preparing refined diesel, which aim at optimizing raw material airspeed based on different raw material oil properties, reducing poor raw material airspeed, increasing high-quality raw material airspeed to further improve refined diesel quality, and aim at optimizing hydrogen partial pressure based on different hydrogen purity, and simultaneously reducing device pressure drop, so as to realize the reduction of device energy consumption while improving refined diesel quality. The process method can not reduce the sulfur and nitrogen content in the diesel to below 5 mug/g, and can not meet the follow-up naphthalene purification process. Patent CN116240045B discloses a process method for deep hydrogenation conversion of high aromatic catalytic cracking diesel, and relates to the technical field of hydrocarbon hydrogenation conversion. The process converts the high-aromatic catalytic cracking diesel oil by using a deep hydrogenation mode for the first time to obtain jet fuel or form a good substitute for coal-based general diesel oil of ground equipment as military diesel oil. The process method only systematically removes sulfur content of diesel oil, does not further explore nitrogen content, does not consider saturation of aromatic hydrocarbon, and is not suitable for processing and producing naphthalene fractions. In summary, the current research on the desulfurization and denitrification process of the aromatic-rich product oil is very few, and the sulfur and nitrogen content of the aromatic-rich diesel is difficult to be reduced to below 5 mug/g by the currently published hydrodesulfurization and denitrification catalyst and hydrofining process, which has great influence on the subsequent process. Therefore, a novel preparation process is developed for desulfurizing and denitrifying the aromatic-rich product oil, and a good foundation is laid for the subsequent production of naphthalene products, so that t