CN-121991719-A - Low-pressure solvent oil removal system and method for solvent deasphalting device

Abstract

The invention provides a low-pressure solvent degreasing system and method of a solvent deasphalting device, which relate to the technical field of solvent deasphalting and are used for solving the problem that oil components in low-pressure solvent of the existing solvent deasphalting device are difficult to remove by using a current method in the prior art. The method adopts the system to construct the flow of primary separation, two-stage condensation, gravity sedimentation and sewage deep separation, and solves the problem of low oil removal efficiency of the prior art by only single gravity sedimentation. The gradual removal of the oil components is realized through multistage treatment, so that the purity of the solvent is obviously improved.

Inventors

• XIA WEIJIAN
• GAO LIANG
• GAO JIAN
• Ying Lieping
• CHEN LINGLING
• LIN ZHIQIANG
• XU JIAN
• LIU RONGBO
• JIN BO
• CHEN JUN
• XIE HAIBING
• WANG SHIWEN
• ZHAO CHANGBIN

Assignees

• 中海石油宁波大榭石化有限公司

Dates

Publication Date

20260508

Application Date

20260326

Claims (10)

1. 1. The low-pressure solvent degreasing system of the solvent deasphalting device is characterized by comprising separating equipment, a heat exchange assembly, solvent sedimentation equipment and sewage separating equipment which are sequentially communicated according to a solvent treatment flow direction, wherein the heat exchange assembly comprises first heat exchange equipment and second heat exchange equipment which are sequentially communicated according to the solvent treatment flow direction.
2. 2. The low-pressure solvent degreasing system of the solvent deasphalting unit of claim 1, wherein the separation means comprises a low-pressure solvent degreasing tank for separating the solvent and the oil components.
3. 3. The low-pressure solvent degreasing system of the solvent deasphalting device as claimed in claim 2, wherein the low-pressure solvent degreasing tank is internally provided with a plurality of stages of cyclone pipes, and the plurality of stages of cyclone pipes are arranged in parallel in the low-pressure solvent degreasing tank.
4. 4. The low-pressure solvent degreasing system of the solvent deasphalting device of claim 1, wherein the first heat exchange equipment comprises a stripping tower top gas steam generator for heat exchanging the solvent with a first cooling medium to obtain a once condensed solvent; the second heat exchange equipment comprises a low-pressure solvent air cooler and is used for carrying out heat exchange between the solvent subjected to primary condensation and a second cooling medium to obtain the solvent subjected to secondary condensation.
5. 5. The low pressure solvent degreasing system of claim 4, wherein the first cooling medium comprises desalted water and the second cooling medium comprises air.
6. 6. A method for removing oil from a solvent by using a low-pressure solvent of a solvent deasphalting device, characterized in that the method comprises the following steps: S1, feeding the stripped oily low-pressure solvent into separation equipment to realize primary separation of the solvent and the oil component; S2, enabling the solvent obtained in the step S1 to enter first heat exchange equipment, and performing heat exchange with a first cooling medium to obtain a solvent after primary condensation; S3, enabling the solvent after primary condensation obtained in the step S2 to enter second heat exchange equipment, and performing heat exchange with a second cooling medium to obtain the solvent after secondary condensation; S4, enabling the solvent obtained in the step S3 after the secondary condensation to enter solvent sedimentation equipment, and separating to obtain purified solvent and oily sewage through gravity sedimentation; S5, the oily sewage obtained in the step S4 enters the sewage separation equipment to realize separation of non-condensable gas, oil residues and purified sewage.
7. 7. The method for removing oil from a solvent at a low pressure by using a solvent deasphalting apparatus as set forth in claim 6, wherein the temperature in the solvent sedimentation device is 20-40 ℃ and the pressure is 0.3-0.6MPa.
8. 8. The method for removing oil from a solvent under low pressure by using a solvent deasphalting apparatus as set forth in claim 6, wherein the pressure in said wastewater separation device is 0.2 to 0.3MPa.
9. 9. The method for removing oil from a solvent under low pressure in a solvent deasphalting apparatus as set forth in claim 6, wherein said oil-containing solvent under low pressure is at a temperature of 250 to 270℃and a pressure of 0.3 to 0.6MPa, and said oil component is at a temperature of 70 to 100 ℃.
10. 10. The method for removing oil from a solvent under low pressure in a solvent deasphalting apparatus as set forth in claim 6, wherein the temperature of the solvent after the primary condensation is 130-150℃and the temperature of the solvent after the secondary condensation is 20-40 ℃.

Description

Low-pressure solvent oil removal system and method for solvent deasphalting device Technical Field The invention relates to the technical field of solvent deasphalting, in particular to a low-pressure solvent deoiling system and method of a solvent deasphalting device. Background The solvent deasphalting process is one of the key technologies for processing heavy oil, and is characterized in that the light separation of the heavy oil is realized by utilizing the different solubilities of asphaltene, colloid and other heavy components in the heavy oil by the solvent. In the process, the solvent is used as a core medium to be recycled, and the purity of the solvent directly influences the separation efficiency, the product quality and the equipment operation stability. The low-pressure solvent treatment flow of the existing solvent deasphalting device is that most of asphalt, heavy deoiling and light deoiling components (the three components are collectively called as oil components) are removed by a stripping device from the extracted low-pressure solvent, and then the low-pressure solvent directly enters a low-pressure solvent tank (a settling tank) for solvent, oil components and water separation, and then the solvent returns to a solvent circulating system. In the existing solvent deasphalting process or waste heat recovery system, the low-pressure solvent is treated and then directly enters a low-pressure solvent tank for separation. However, the stripped low-pressure solvent still carries part of asphalt, heavy deoiling and light deoiling components, and the traditional low-pressure solvent tank only relies on gravity sedimentation to separate the solvent from the oil components, so that the removal efficiency of the oil components is extremely low. When the oil-containing solvent is recycled, oil is easy to deposit and scale in equipment such as a heat exchanger, a pump body and the like, so that the heat transfer efficiency is reduced, the equipment abrasion is increased, and the equipment is required to be stopped for cleaning when serious, so that the continuous operation of the device is affected. Residual oil also reduces the selective solvency of the solvent for heavy oil, resulting in reduced yields for heavy and light deoiling and fluctuations in product quality. Part of the oil is discharged along with sewage, and the environmental-friendly treatment cost is increased. Therefore, a low-pressure solvent degreasing system and method for a solvent deasphalting device are needed to solve the above technical problems. Disclosure of Invention The invention aims to provide a low-pressure solvent deoiling system and method for a solvent deasphalting device, which are used for solving the problem that oil components in low-pressure solvent of the existing solvent deasphalting device are difficult to remove by using the existing method in the prior art. The preferred technical solutions of the technical solutions provided by the present invention can produce a plurality of technical effects described below. In order to achieve the above purpose, the present invention provides the following technical solutions: In a first aspect, the low-pressure solvent degreasing system of the solvent deasphalting device provided by the invention comprises separating equipment, a heat exchange assembly, solvent sedimentation equipment and sewage separating equipment which are sequentially communicated according to a solvent treatment flow direction, wherein the heat exchange assembly comprises first heat exchange equipment and second heat exchange equipment which are sequentially communicated according to the solvent treatment flow direction. Preferably, the separation apparatus comprises a low pressure solvent knock-out tank for separating solvent and oil components. Preferably, a multi-stage swirl tube is arranged in the low-pressure solvent degassing tank, and the multi-stage swirl tube is arranged in parallel in the low-pressure solvent degassing tank. Preferably, the first heat exchange device comprises a stripping tower top gas steam generator for carrying out heat exchange between the solvent and a first cooling medium to obtain a solvent after primary condensation; the second heat exchange equipment comprises a low-pressure solvent air cooler and is used for carrying out heat exchange between the solvent subjected to primary condensation and a second cooling medium to obtain the solvent subjected to secondary condensation. Preferably, the first cooling medium comprises desalinated water and the second cooling medium comprises air. In a second aspect, the invention provides a low-pressure solvent degreasing method for a solvent deasphalting device, which adopts the low-pressure solvent degreasing system for the solvent deasphalting device, and comprises the following steps: S1, feeding the stripped oily low-pressure solvent into separation equipment to realize primary separation of the solvent and the oil compon