Solvent extraction and purification system and method for sulfolane

Abstract

The invention belongs to the field of petroleum refining, and particularly discloses a sulfolane solvent extraction, separation and purification system and method.The sulfolane solvent containing heavy non-aromatic impurities is cooled through a desolventizer cooler and then conveyed to a solvent extraction and separation barrel, demineralized water is added at the same time for extraction and separation, and the purified sulfolane solvent is obtained; the purified sulfolane solvent is input into the aromatic hydrocarbon extraction system again through a solvent supplementing pump, and the process is repeated for multiple times, so that heavy non-aromatic hydrocarbon oil in the sulfolane solvent can be effectively removed, stable operation of the aromatic hydrocarbon extraction device is ensured, the impact resistance of the device is improved, heavy non-aromatic hydrocarbon in the solvent is separated out, long-period operation is ensured, and the production cost is reduced. The product quality is qualified.

Description

Technical Field

[0001] The present invention belongs to the field of petroleum refining, and particularly relates to a system and method for solvent extraction separation and purification of sulfolane. Background Art

[0002] Sulfolane is an ideal solvent in the aromatics extraction process. Sulfolane has strong polarity and good thermochemical stability. It is completely miscible with water and is an excellent solvent for most organic substances and polymers. Sulfolane has high solubility and selectivity for aromatics. At the same time, the density difference between sulfolane and the feedstock oil and the boiling point difference of gasoline aromatics are relatively large, and the latent heat of vaporization and specific heat are small, so a high aromatics yield can be obtained. The aromatics extraction and distillation unit adopts the sulfolane extraction and distillation process, and uses the different effects of the solvent on the relative volatility of each component in the raw material to separate aromatics from non-aromatics through extractive distillation. The solvent and the C6 fraction contact in the extraction and distillation tower to form gas-liquid two phases. Since the interaction between the solvent and aromatics is stronger, non-aromatics are enriched in the gas phase and discharged from the top of the tower; aromatics are enriched in the liquid phase and purified, and discharged from the bottom of the tower. The liquid phase enriched with aromatics enters the solvent recovery tower, where the aromatics and the solvent are separated, and the solvent is recycled. Therefore, the quality of the sulfolane solvent in the aromatics extraction system is the key to ensuring the long-term operation of the device.

[0003] During the operation of the device, during operations such as process switching, heavy non-aromatic impurities are extremely likely to be mixed into the sulfolane solvent, resulting in a decrease in the solvent purity, a decrease in the solubility and selectivity of the solvent, unstable product quality, and frequent fluctuations in the liquid level of the extraction and distillation tower. Summary of the Invention

[0004] The purpose of the present invention is to provide a system and method for solvent extraction separation and purification of sulfolane to solve the problem that when the sulfolane solvent is used in the aromatics extraction process in the aromatics extraction system, heavy non-aromatic impurities are easily mixed in, resulting in a decrease in the solvent purity and unstable product quality.

[0005] To achieve the above purpose, the present invention adopts the following technical solutions:

[0006] In the first aspect, the present invention provides a system for solvent extraction separation and purification of sulfolane, including:

[0007] A solvent stripping cooler, a solvent extraction and separation barrel, and a make-up solvent pump; the inlet of the solvent stripping cooler is connected to the outlet of the solvent stripping line of the aromatics extraction system, the outlet of the solvent stripping cooler is connected to the inlet of the solvent extraction and separation barrel, the inlet of the solvent extraction and separation barrel is also connected to a desalted water injection valve, and the outlet of the solvent extraction and separation barrel is connected to the inlet of the make-up solvent pump.

[0008] Further, a solvent stripping valve is provided on the pipeline connecting the solvent stripping cooler and the aromatics extraction system, and the sulfolane solvent containing heavy non-aromatic impurities is transported from the aromatics extraction system to the solvent stripping cooler through the solvent stripping valve.

[0009] Further, a shell-side outlet valve is provided on the connecting pipeline between the solvent stripper cooler and the solvent extraction separation tank, and the cooled sulfolane solvent containing heavy non-aromatic impurities is transported into the solvent extraction separation tank through the shell-side outlet valve.

[0010] Further, the demineralized water injection valve is used to input demineralized water into the solvent extraction separation tank.

[0011] Further, a make-up solvent pump inlet valve is provided on the connecting pipeline between the solvent extraction separation tank and the make-up solvent pump, and the purified sulfolane solvent is input into the make-up solvent pump through the make-up solvent pump inlet valve.

[0012] Further, the outlet of the make-up solvent pump is connected to the make-up solvent pump outlet valve, and the purified sulfolane solvent is transported back into the aromatics extraction system.

[0013] Further, the outlet of the solvent extraction separation tank is also connected to a drain valve, and the upper layer liquid after extraction separation and purification is transported into an oil barrel through the drain valve.

[0014] In a second aspect, the present invention provides a method for extracting, separating, and purifying a sulfolane solvent, based on any one of the above-mentioned sulfolane solvent extraction, separation, and purification systems, including:

[0015] The sulfolane solvent containing heavy non-aromatic impurities is transported into the solvent stripper cooler, and under the action of cooling water, the cooled sulfolane solvent containing heavy non-aromatic impurities is transported into the solvent extraction separation tank;

[0016] The demineralized water is transported into the solvent extraction separation tank through the injection control valve, and the cooled sulfolane solvent containing heavy non-aromatic impurities is separated from the demineralized water by extraction to obtain a purified water-containing sulfolane solvent;

[0017] The purified water-containing sulfolane solvent is transported into the make-up solvent pump and finally transported into the aromatics extraction system.

[0018] Further, the sulfolane solvent containing heavy non-aromatic impurities is transported into the solvent stripper cooler, and under the action of cooling water, the cooled sulfolane solvent containing heavy non-aromatic impurities is transported into the solvent extraction separation tank, specifically:

[0019] Slightly open the solvent stripper valve and the shell-side outlet valve, and transport the sulfolane solvent containing heavy non-aromatic impurities through the solvent stripper cooler into the solvent extraction separation tank;

[0020] Observe the liquid level of the solvent extraction separation tank. When the liquid level reaches 700 mm, immediately close the solvent stripper valve and the shell-side outlet valve.

[0021] Further, the process of transporting demineralized water to the solvent extraction separation tank through the water injection control valve, and obtaining the purified sulfolane solvent after the extraction separation of the cooled sulfolane solvent containing heavy non-aromatic impurities and demineralized water is as follows:

[0022] Slightly open the demineralized water injection valve to transport demineralized water to the solvent extraction separation tank. Observe the liquid level in the solvent extraction separation tank. When the liquid level rises to 900 mm, immediately close the demineralized water injection valve;

[0023] The cooled sulfolane solvent containing heavy non-aromatic impurities is miscible with demineralized water. After standing, it will be stratified. The upper stratified liquid is the oil phase, and the lower stratified liquid is the purified water-containing sulfolane solvent.

[0024] The present invention has at least the following beneficial effects:

[0025] 1. In the present invention, the sulfolane solvent containing heavy non-aromatic impurities is cooled by a solvent removal cooler and then transported to the solvent extraction separation tank. At the same time, demineralized water is added for extraction separation to obtain the purified sulfolane solvent. The purified sulfolane solvent is re-introduced into the aromatics extraction system through a make-up solvent pump. Repeating the above process multiple times can effectively remove the heavy non-aromatic oil in the sulfolane solvent, ensure the stable operation of the aromatics extraction unit, improve the shock resistance of the unit, separate the heavy non-aromatics in the solvent, ensure long-term operation, and the product quality is qualified.

[0026] 2. After extraction separation and purification in the present invention, the content of heavy non-aromatic impurities mixed in the sulfolane solvent is reduced from 32% to 10%, and the purity of the sulfolane solvent is increased from about 68% to 90%. Further improving the purity of the solvent enhances the solubility and selectivity of the solvent. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The specification drawings forming a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention.

[0028] In the drawings:

[0029] Figure 1 is a schematic structural diagram of a sulfolane solvent extraction separation and purification system;

[0030] Figure 2 is a schematic process flow diagram of a sulfolane solvent extraction separation and purification method;

[0031] Figure 3 is a graph showing the rising trend of the purity of the aromatics extraction sulfolane solvent;

[0032] Reference numerals: 1, stripping solvent cooler; 2, solvent extraction and separation tank; 3, make-up solvent pump; 4, stripping solvent valve; 5, shell-side outlet valve; 6, demineralized water injection valve; 7, drain valve; 8, make-up solvent pump inlet valve; 9, make-up solvent pump outlet valve. Detailed implementation mode

[0033] The present invention will be described in detail below with reference to the drawings and in combination with embodiments. It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other.

[0034] The following detailed descriptions are all exemplary descriptions, aiming to provide further detailed descriptions of the present invention. Unless otherwise specified, all technical terms adopted by the present invention have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention belongs. The terms used in the present invention are only for describing specific implementation modes and are not intended to limit the exemplary implementation modes according to the present invention.

[0035] Embodiment 1

[0036] As Figure 1 shown, a sulfolane solvent extraction, separation and purification system includes:

[0037] A stripping solvent cooler 1, a solvent extraction and separation tank 2 and a make-up solvent pump 3; the inlet of the stripping solvent cooler 1 is connected to the outlet of the stripping solvent line of the aromatics extraction system, and a stripping solvent valve 4 is arranged on the connecting pipeline between the stripping solvent cooler 1 and the aromatics extraction system. The sulfolane solvent containing heavy non-aromatic impurities is transported from the aromatics extraction system through the stripping solvent valve 4 into the stripping solvent cooler 1; the stripping solvent valve 4 is used to control the entry of the sulfolane solvent containing heavy non-aromatic impurities into the stripping solvent cooler 1;

[0038] The outlet of the stripping solvent cooler 1 is connected to the inlet of the solvent extraction and separation tank 2, and a shell-side outlet valve 5 is arranged on the connecting pipeline between the stripping solvent cooler 1 and the solvent extraction and separation tank 2. The cooled sulfolane solvent containing heavy non-aromatic impurities is transported into the solvent extraction and separation tank 2 through the shell-side outlet valve 5; the outlet valve 5 is used to control the entry of the cooled sulfolane solvent containing heavy non-aromatic impurities into the solvent extraction and separation tank 2;

[0039] The inlet of the solvent extraction and separation tank 2 is also connected to a demineralized water injection valve 6, and demineralized water is input into the solvent extraction and separation tank 2 through the demineralized water injection valve 6; the cooled sulfolane solvent containing heavy non-aromatic impurities completes extraction, separation and purification in the solvent extraction and separation tank 2 to obtain an upper-layer liquid and a lower-layer purified sulfolane solvent;

[0040] The solvent extraction and separation tank 2 is marked with a scale of 0 - 1000 mm and is an atmospheric pressure facility;

[0041] The outlet of the solvent extraction and separation drum 2 is connected to the inlet of the make-up solvent pump 3. A make-up solvent pump inlet valve 8 is provided on the connecting pipeline between the solvent extraction and separation drum 2 and the make-up solvent pump 3. The make-up solvent pump inlet valve 8 inputs the purified sulfolane solvent into the make-up solvent pump 3. The outlet of the make-up solvent pump 3 is connected to the make-up solvent pump outlet valve 9, and the purified sulfolane solvent is re-transported into the aromatics extraction system.

[0042] The outlet of the solvent extraction and separation drum 2 is also connected to a drain valve 7. The upper layer of the liquid after extraction, separation, and purification is transported into an oil drum through the drain valve 7.

[0043] Example 2

[0044] As Figure 2 shown, a method for solvent extraction, separation, and purification of sulfolane solvent includes:

[0045] S1: The sulfolane solvent containing heavy non-aromatic impurities is transported into the solvent remover cooler 1. Under the action of cooling water, the cooled sulfolane solvent containing heavy non-aromatic impurities is transported into the solvent extraction and separation drum 2.

[0046] Specifically, before transporting the sulfolane solvent containing heavy non-aromatic impurities, it should be confirmed that the solvent remover cooler 1 and the solvent extraction and separation drum 2 are hermetically connected.

[0047] Demineralized water is transported to the demineralized water injection valve 6, and cooling water is transported into the solvent remover cooler 1. Slightly open the solvent removal valve 4 and the shell side outlet valve 5, and transport the sulfolane solvent containing heavy non-aromatic impurities through the solvent remover cooler 1 into the solvent extraction and separation drum 2.

[0048] Observe the liquid level of the solvent extraction and separation drum 2. When the liquid level reaches 700 mm, immediately close the solvent removal valve 4 and the shell side outlet valve 5. The determination of the liquid level height is based on analyzing the content of heavy non-aromatic hydrocarbons in the sulfolane solvent and calculating the amount of demineralized water to be extracted.

[0049] S2: Demineralized water is transported into the solvent extraction and separation drum 2 through the injection control valve 6. After the cooled sulfolane solvent containing heavy non-aromatic impurities is extracted and separated from the demineralized water, a purified water-containing sulfolane solvent is obtained.

[0050] Specifically, slightly open the demineralized water injection valve 6, transport demineralized water into the solvent extraction and separation drum 2, observe the liquid level of the solvent extraction and separation drum 2, and when the liquid level rises to 900 mm, immediately close the demineralized water injection valve 6.

[0051] The cooled sulfolane solvent containing heavy non-aromatic impurities is miscible with demineralized water in any ratio. After standing for 30 minutes, it is stratified. Observe the stratification situation. The upper layer of the liquid is the oil phase, and the lower layer of the liquid is the purified water-containing sulfolane solvent.

[0052] S3: Open the drain valve 7, drain the upper part of the oil phase into an oil barrel for collection, and transport the purified sulfolane solvent containing water to the make-up solvent pump 3 through the make-up solvent pump inlet valve 8, and then transport it to the aromatics extraction system through the make-up solvent pump outlet valve 9.

[0053] After each completion of the above process, make relevant records and repeat the above process several times.

[0054] By adopting this solution, through chemical analysis and drawing Figure 3 , it can be clearly seen from Figure 3 that the purity of the sulfolane solvent in the aromatics extraction is gradually increasing, and the impact resistance of the aromatics extraction system is further enhanced.

[0055] As is known to those skilled in the art, the present invention can be implemented by other embodiments that do not depart from its spirit or essential features. Therefore, the above-disclosed embodiments are illustrative in all aspects and not exclusive. All changes within the scope of the present invention or equivalent to the present invention are encompassed by the present invention.

[0056] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: the specific embodiments of the present invention can still be modified or equivalently replaced, and any modification or equivalent replacement that does not depart from the spirit and scope of the present invention shall be covered by the protection scope of the claims of the present invention.

Claims

1. A sulfolane solvent extraction separation and purification system, characterized in that, it includes: a stripping solvent cooler (1), a solvent extraction separation tank (2) and a make-up solvent pump (3); the inlet of the stripping solvent cooler (1) is connected to the outlet of the stripping solvent line of the aromatics extraction system, the outlet of the stripping solvent cooler (1) is connected to the inlet of the solvent extraction separation tank (2), and the inlet of the solvent extraction separation tank (2) is also connected to a desalted water injection valve (6), and the outlet of the solvent extraction separation tank (2) is connected to the inlet of the make-up solvent pump (3).

2. The sulfolane solvent extraction separation and purification system according to claim 1, characterized in that, a stripping solvent valve (4) is provided on the connection pipeline between the stripping solvent cooler (1) and the aromatics extraction system, and the sulfolane solvent containing heavy non-aromatic impurities is transported from the aromatics extraction system through the stripping solvent valve (4) into the stripping solvent cooler (1).

3. The sulfolane solvent extraction separation and purification system according to claim 1, characterized in that, a shell side outlet valve (5) is provided on the connection pipeline between the stripping solvent cooler (1) and the solvent extraction separation tank (2), and the cooled sulfolane solvent containing heavy non-aromatic impurities is transported through the shell side outlet valve (5) into the solvent extraction separation tank (2).

4. The sulfolane solvent extraction separation and purification system according to claim 1, characterized in that, the desalted water injection valve (6) is used to input desalted water into the solvent extraction separation tank (2).

5. The sulfolane solvent extraction separation and purification system according to claim 1, characterized in that, a make-up solvent pump inlet valve (8) is provided on the connection pipeline between the solvent extraction separation tank (2) and the make-up solvent pump (3), and the make-up solvent pump inlet valve (8) inputs the purified sulfolane solvent into the make-up solvent pump (3).

6. The sulfolane solvent extraction separation and purification system according to claim 1, characterized in that, the outlet of the make-up solvent pump (3) is connected to a make-up solvent pump outlet valve (9), and the purified sulfolane solvent is re-transported into the aromatics extraction system.

7. The sulfolane solvent extraction separation and purification system according to claim 1, characterized in that, the outlet of the solvent extraction separation tank (2) is also connected to a drain valve (7), and the upper layer liquid after extraction separation and purification is transported through the drain valve (7) into an oil barrel.

8. A sulfolane solvent extraction separation and purification method, characterized in that, based on the sulfolane solvent extraction separation and purification system according to any one of claims 1-7, it includes: transporting the sulfolane solvent containing heavy non-aromatic impurities into the stripping solvent cooler (1), and under the action of cooling water, transporting the cooled sulfolane solvent containing heavy non-aromatic impurities to the solvent extraction separation tank (2); transporting desalted water through the water injection control valve (6) into the solvent extraction separation tank (2), and after extraction separation of the cooled sulfolane solvent containing heavy non-aromatic impurities and desalted water, obtaining the purified water-containing sulfolane solvent; transporting the purified water-containing sulfolane solvent to the make-up solvent pump (3), and finally transporting it to the aromatics extraction system.

9. The sulfolane solvent extraction separation and purification method according to claim 8, characterized in that, The sulfolane solvent containing heavy non-aromatic impurities is transported into the solvent cooler (1). Under the action of cooling water, the cooled sulfolane solvent containing heavy non-aromatic impurities is transported to the solvent extraction and separation tank (2). Specifically: Slightly open the solvent valve (4) and the shell-side outlet valve (5), and transport the sulfolane solvent containing heavy non-aromatic impurities to the solvent extraction and separation tank (2) through the solvent cooler (1); Observe the liquid level of the solvent extraction and separation tank (2). When the liquid level reaches 700 mm, immediately close the solvent valve (4) and the shell-side outlet valve (5).

10. A method for extracting, separating and purifying sulfolane solvent according to claim 9, characterized in that the demineralized water is transported to the solvent extraction and separation tank (2) through the water injection control valve (6), and the purified sulfolane solvent is obtained after the cooled sulfolane solvent containing heavy non-aromatic impurities is extracted and separated from the demineralized water. Specifically: Slightly open the demineralized water injection valve (6), transport demineralized water to the solvent extraction and separation tank (2), observe the liquid level of the solvent extraction and separation tank (2). When the liquid level rises to 900 mm, immediately close the demineralized water injection valve (6); The cooled sulfolane solvent containing heavy non-aromatic impurities is miscible with the demineralized water. After standing, it is stratified. The upper stratified liquid is the oil phase, and the lower stratified liquid is the purified water-containing sulfolane solvent.

Images