Absorption and desorption system

Abstract

The invention relates to the technical field of petrochemical industry, and discloses an absorption and desorption system, which comprises a first cooler (6), a condensation oil tank (1), an absorption tower (2), an absorption tower I intermediate reflux (3), an absorption tower II intermediate reflux (4), a desorption tower (8), a stabilization tower (13) and a re-absorption tower (21), a crude gasoline pipeline for adding crude gasoline and a crude gasoline branch bypass-connected to the crude gasoline pipeline are arranged at the top of the absorption tower, and the crude gasoline branch bypass-connected to the first absorption tower middle reflux (3) and the second absorption tower middle reflux (4) respectively. According to the technical scheme, the crude gasoline pipeline is respectively connected to the tower top of the absorption tower, the first middle reflux of the absorption tower and the second middle reflux of the absorption tower, so that the crude gasoline enters the absorption tower from the tower top, the first middle reflux and the second middle reflux respectively, three-section feeding of the crude gasoline is realized, an absorbent is more uniformly distributed in the tower, the absorption effect is fully exerted, and the production efficiency is improved. The C3 + content in the rich gas can be effectively reduced.

Description

Technical Field

[0001] The invention relates to the technical field of petrochemical industry, in particular to an absorption analysis system. Background Art

[0002] The by-product dry gas in the catalytic cracking process of petroleum has a low product value. It is used as fuel after being concentrated in domestic refineries. The C3 and C4 components carried in the dry gas are high value-added product components of the device, and their use value is much higher than that of the dry gas. It can be seen that reducing the C3+ content of catalytic cracking dry gas is crucial to improving the economic benefits of the device. If the C3+ component content in the catalytic dry gas can be reduced, it can not only bring economic benefits, but also improve the competitiveness of oil refining enterprises. Therefore, reducing the C3+ content of catalytic cracking dry gas is of great significance.

[0003] At present, the technology for reducing the C3+ content of dry gas in catalytic cracking units is mainly the absorption analysis method, which mainly uses the different solubility of each component of catalytic cracking dry gas in the absorbent to separate. Figure 1 As shown, the compressed rich gas from the gas compressor, the analytical gas at the top of the analytical tower, and the rich absorption oil at the bottom of the absorption tower are cooled and enter the oil-gas separator, and the rich gas and condensed oil reach a phase equilibrium; the rich gas from the oil-gas separator enters the lower part of the absorption tower, and enters the upper part of the absorption tower with the crude gasoline from the fractionation system, and the two are countercurrently absorbed. In addition, a part of the stable gasoline from the bottom of the stabilization tower is used as a supplementary absorbent, and most of the C3 and C4 components in the absorption tower are absorbed; the absorbent of this process is the crude gasoline from the fractionation part, and the supplementary absorbent is the stable gasoline from the bottom of the stabilization tower. The absorbent and the supplementary absorbent are in reverse contact with the gas from the top of the absorption tower to absorb the heavy components in the rich gas components and reduce the C3+ content of the dry gas. Among them, heat is generated during the absorption reaction, resulting in a high overall temperature of the absorption tower. The high temperature will affect the absorption effect. A large number of C3 and C4 components circulate between the absorption tower and the analytical tower, and the absorption and analytical effects are not good. Using this method, the C3+ content of the dry gas is high, generally maintained above 3.5%v, and the operation flexibility is limited.

[0004] Extensive research has been conducted on how to effectively reduce the C3+ content of dry gas in catalytic cracking units. Although some technical transformation measures have been adopted in domestic catalytic cracking units to reduce the C3+ content of dry gas, such as reducing the absorbent temperature, increasing the flow rate of supplementary absorbent, reducing the temperature at the bottom of the desorption tower, and increasing the pressure of the desorption tower, the original process flow has been fixed, and the above optimization measures have limited operational flexibility and the implementation effect is not obvious, and the problem of high C3+ content in dry gas cannot be completely solved. Summary of the invention

[0005] The purpose of the present invention is to overcome the problem of high C3+ content in dry gas in the prior art and to provide an absorption and analysis system which can reduce the overall temperature of the absorption tower and increase the absorption effect.

[0006] In order to achieve the above-mentioned object, the present invention provides an absorption and analysis system, comprising a first cooler, a condensed oil tank, an absorption tower, a reflux in the first absorption tower, a reflux in the second absorption tower, a analysis tower, a stabilization tower and a reabsorption tower, wherein the outlet end of the first cooler is connected to the inlet end of the condensed oil tank, the outlet end of the condensed oil tank is respectively connected to the bottom inlet end of the absorption tower and the top inlet end of the analysis tower, the reflux in the first absorption tower and the reflux in the second absorption tower are respectively arranged in the middle of the absorption tower, the top outlet end of the absorption tower is connected to the tower inlet end of the reabsorption tower The bottom inlet end of the absorption tower is connected, the bottom outlet end of the absorption tower is connected to the inlet end of the first cooler, the bottom outlet end of the analysis tower is connected to the feed inlet end of the stabilization tower, the top outlet end of the analysis tower is connected to the inlet end of the first cooler, and the bottom outlet end of the stabilization tower is connected to the top of the absorption tower; wherein, the top of the absorption tower is provided with a crude gasoline pipeline for adding crude gasoline and a crude gasoline branch bypassed on the crude gasoline pipeline, and the crude gasoline branch is respectively bypassed on the reflux in the absorption tower one and the reflux in the absorption tower two.

[0007] Optionally, a second cooler is further included, the outlet end of the second cooler is connected to the inlet end of the first cooler, and the bottom outlet end of the absorption tower is connected between the first cooler and the second cooler.

[0008] Optionally, the reflux in the first absorption tower includes a cooler and a reflux pump, the reflux in the second absorption tower includes a second cooler and a second reflux pump, and the crude gasoline branch is respectively connected to the outlet end of the first reflux pump and the outlet end of the second reflux pump.

[0009] Optionally, a middle section reboiler is provided in the middle section of the analytical tower.

[0010] Optionally, a reboiler is provided at the bottom of the analytical tower.

[0011] Optionally, a heat exchanger is provided at the top of the analytical tower, and two ends of the heat exchanger are connected with a jumper pipe, and a flow regulating valve is provided on the jumper pipe.

[0012] Optionally, a heat exchanger is further included, wherein a first channel of the heat exchanger is connected between the analysis tower and the stabilization tower, and a second channel of the heat exchanger is connected between the stabilization tower and the absorption tower.

[0013] Optionally, it also includes a desalted water heat exchanger, a condensed oil heat exchanger and an air cooler which are sequentially connected to the stabilization tower and the absorption tower.

[0014] Optionally, a reflux tank is further included, wherein the inlet end of the reflux tank is connected to the outlet end of the top of the stabilization tower, and the outlet end of the reflux tank is connected to the inlet end of the top of the stabilization tower.

[0015] Optionally, a reboiler is provided at the bottom of the stabilization tower.

[0016] Through the above technical scheme, the feed of crude gasoline is modified, a crude gasoline bypass is added, and the crude gasoline pipeline is connected to the top of the absorption tower, the first reflux of the absorption tower, and the second reflux of the absorption tower, respectively, so that the crude gasoline enters the absorption tower from the top of the tower, the first reflux, and the second reflux, respectively, to achieve three-stage feeding of crude gasoline, so that the absorbent is more evenly distributed in the tower, the absorption effect is fully exerted, and the temperature in the absorption tower can be made more balanced, preventing the phenomenon of high temperature at the top of the tower and low temperature at the bottom of the tower from affecting the absorption effect, and can effectively reduce the C3+ content in the rich gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural schematic diagram of an absorption and analysis system in the prior art;

[0018] Figure 2 It is a structural schematic diagram of an implementation mode of the absorption analysis system in the present invention.

[0019] Description of Reference Numerals

[0020] 1. Condensate oil tank, 2. Absorption tower, 3. Absorption tower first reflux, 4. Absorption tower second reflux, 5. Second cooler, 6. First cooler, 7. Condensate oil pump, 8. Analysis tower, 9. First reboiler, 10. Second reboiler, 11. Heat exchanger, 12. Middle reboiler, 13. Stabilization tower, 14. Heat exchanger, 15. Air cooler, 16. Desalted water heat exchanger, 17. Condensate oil heat exchanger, 18. Supplementary absorbent pump, 19. Reflux tank, 20. Third reboiler, 21. Reabsorption tower, 31. First cooler, 32. First reflux pump, 41. Second cooler, 42. Second reflux pump. DETAILED DESCRIPTION

[0021] The specific implementation of the present invention is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the present invention, and is not used to limit the present invention.

[0022] The present invention provides an absorption and analysis system, comprising a first cooler 6, a condensed oil tank 1, an absorption tower 2, a reflux 3 in the first absorption tower, a reflux 4 in the second absorption tower, a analysis tower 8, a stabilization tower 13 and a reabsorption tower 21, wherein the outlet end of the first cooler 6 is connected to the inlet end of the condensed oil tank 1, the outlet end of the condensed oil tank 1 is respectively connected to the bottom inlet end of the absorption tower 2 and the top inlet end of the analysis tower 8, the reflux 3 in the first absorption tower and the reflux 4 in the second absorption tower are respectively arranged in the middle of the absorption tower 2, the top outlet end of the absorption tower 2 is connected to the bottom inlet end of the reabsorption tower 21, and the bottom outlet end of the absorption tower 2 is connected to the bottom outlet end of the absorption tower 2. The end is connected to the inlet end of the first cooler 6, the bottom outlet end of the analysis tower 8 is connected to the feed inlet end of the stabilization tower 13, the top outlet end of the analysis tower 8 is connected to the inlet end of the first cooler 6, and the bottom outlet end of the stabilization tower 13 is connected to the top of the absorption tower 2; wherein, the top of the absorption tower 2 is provided with a crude gasoline pipeline for adding crude gasoline and a crude gasoline branch bypassed on the crude gasoline pipeline, and the crude gasoline branch is respectively bypassed on the reflux 3 in the absorption tower one and the reflux 4 in the absorption tower two, so that part of the crude gasoline can be input into the absorption tower 2 through the reflux 3 in the absorption tower one and the reflux 4 in the absorption tower two.

[0023] The connection points of the crude gasoline pipeline, the reflux 3 in the absorption tower 1 and the reflux 4 in the absorption tower 2 with the absorption tower 2 are arranged at intervals in the height direction so that the crude gasoline can be input into the absorption tower 2 at different heights. Figure 2 As shown, in the absorption tower 2, the lean absorption oil (crude gasoline and stabilized gasoline) enters the tower from the top and then goes down, and the concentration of C3 and above components thereof gradually increases, and makes multiple gas-liquid reverse contacts on the tower plates with the hydrocarbon mixed gas entering the tower from the bottom tower plate and rising, and the concentration of C3 and above components thereof gradually decreases, completing the absorption process; the gas of the catalytic cracking unit itself and most of the external gas pass through the main fractionation tower fixed liquid separator, and after flash evaporation in the liquid separator, the gaseous phase component (i.e., rich gas) enters the first cooler 6, and the liquid phase component (i.e., crude gasoline) enters the absorption tower 2. If the crude gasoline enters the absorption tower 2 at a position that is too high, desorption will occur, thereby increasing the content of C3 and above components in the dry gas. If the crude gasoline enters the absorption tower 2 at a position that is too low, the number of plates where absorption occurs will be too small, which will also affect the absorption effect.

[0024] Through the above technical scheme, the feed of crude gasoline is modified, a crude gasoline bypass is added, and the crude gasoline pipeline is connected to the top of the absorption tower, the first reflux 3 of the absorption tower, and the second reflux 4 of the absorption tower, respectively, so that the crude gasoline enters the absorption tower from the top of the tower, the first reflux and the second reflux, respectively, to achieve three-stage feeding of crude gasoline, so that the absorbent is more evenly distributed in the tower, the absorption effect is fully exerted, and the temperature in the absorption tower can be made more balanced, preventing the phenomenon of high temperature at the top of the tower and low temperature at the bottom of the tower from affecting the absorption effect, and can effectively reduce the C3+ content in the rich gas.

[0025] Furthermore, the absorption and analysis system also includes a second cooler 5 , the outlet end of the second cooler 5 is connected to the inlet end of the first cooler 6 , and the bottom outlet end of the absorption tower 2 is connected between the first cooler 6 and the second cooler 5 .

[0026] like Figure 2 As shown, the first cooler 6 is a wet air cooler, and the second cooler 5 is a dry air cooler. The second cooler 5 can cool the rich gas first, and then the rich gas is mixed with the saturated absorption oil at the bottom of the absorption tower 2 and cooled by the first cooler 6. This cooling method combining dry and wet air cooling can save the consumption of desalted water of the device while meeting the production operation, and can effectively reduce the energy consumption of the device; the cooled mixed material is separated into gas phase and oil phase through the condensation oil tank 1, the gas phase enters the absorption tower 2, and the oil phase enters the analysis tower 8.

[0027] In some embodiments, the reflux 3 in the first absorption tower includes a first cooler 31 and a first reflux pump 32, the reflux 4 in the second absorption tower includes a second cooler 41 and a second reflux pump 42, and the crude gasoline branch is respectively connected to the outlet end of the first reflux pump 32 and the outlet end of the second reflux pump 42.

[0028] like Figure 2 As shown, the reflux 3 in the first absorption tower and the reflux 4 in the second absorption tower are arranged in the middle position of the absorption tower 2 (respectively arranged in the upper middle and lower middle positions of the absorption). Taking the absorption tower 2 with 35 layers of double overflow trays as an example, the crude gasoline pipeline is connected to the 30th layer of the absorption tower 2, the reflux 3 in the first absorption tower is pumped out from the 26th layer through the first reflux pump 32 and returns to the 25th layer through the first cooler 31, and the reflux 4 in the second absorption tower is pumped out from the 15th layer through the second cooler 41 and returns to the 14th layer through the second reflux pump 42, and the crude gasoline branches are respectively connected to the outlet ends of the first cooler 31 and the second cooler 41.

[0029] As an optional implementation, a middle section reboiler 12 is provided in the middle section of the analytical tower 8 .

[0030] like Figure 2 As shown, the material is extracted from the middle of the analysis tower 8 and enters the middle reboiler 12, and exchanges heat with the deethanized gasoline from the bottom of the stabilization tower 13. The material in the middle of the analysis tower 8 is heated and then returned to the tower; the bottom temperature of the analysis tower 8 is 120°C, which is relatively low, so that the analysis temperature in the middle of the analysis tower 8 is not enough to affect the analysis effect, so the middle reboiler 12 is added, the temperature in the middle of the analysis tower is increased, and the analysis effect is increased.

[0031] Furthermore, a reboiler is provided at the bottom of the analysis tower 8 .

[0032] like Figure 2As shown, in the present application, two reboilers are provided at the bottom of the analysis tower 8, the first reboiler 9 uses lean absorption oil as a heat source, and the second reboiler 10 uses the heat source in the distillation tower 1 as a heat source, the purpose of which is to meet the heat required for analysis. By using two reboilers, the temperature at the bottom of the analysis tower can reach 120°C; if only one reboiler is used, the heat requirement of the analysis tower cannot be met, causing the liquefied gas to carry a large amount of light components, thereby causing the C2 content of the liquefied gas at the key quality control point to exceed the standard.

[0033] The desorption tower is technically modified with an intermediate reboiler. The heat required for the bottom reboiler is lower than that of the cold feed method, so that the low-temperature heat of the stable gasoline can be recovered, the content of components above C3 in the desorbed gas and dry gas is reduced, and the load of the absorption system is reduced, which combines the advantages of both cold feed and hot feed.

[0034] A heat exchanger 11 is provided at the top of the analytical tower 8, and both ends of the heat exchanger 11 are connected with a jumper pipe, and a flow regulating valve is provided on the jumper pipe.

[0035] like Figure 2 As shown, the condensed oil extracted from the condensed oil tank 1 is sent to the heat exchanger 11 through the condensed oil pump 7, and enters the analysis tower 8 from the top of the tower. By setting a jumper pipeline, the condensed oil enters the heat exchanger 11 all the way, and the other part bypasses the heat exchanger 11 through the jumper pipeline. By adjusting the flow regulating valve, the amount of condensed oil entering the heat exchanger 11 can be controlled to achieve the adjustment of the top temperature of the analysis tower 8.

[0036] Furthermore, the absorption and decomposition system also includes a heat exchanger 14 , a first channel of the heat exchanger 14 is connected between the decomposition tower 8 and the stabilization tower 13 , and a second channel of the heat exchanger 14 is connected between the stabilization tower 13 and the absorption tower 2 .

[0037] like Figure 2 As shown, heat exchange between the stabilized gasoline and the deethanized gasoline is achieved through the heat exchanger 14, that is, the bottom oil of the analysis tower and the feed of the stabilizer tower are heated to achieve the stabilized gasoline.

[0038] Furthermore, the absorption and analysis system also includes a desalted water heat exchanger 16 , a condensed oil heat exchanger 17 and an air cooler 15 which are sequentially connected to the stabilization tower 13 and the absorption tower 2 .

[0039] like Figure 2As shown, in the desalted water heat exchanger 16, the stabilized gasoline exchanges heat with the desalted water to achieve cooling of the stabilized gasoline, and the stabilized gasoline exchanges heat with the material in the middle of the analysis tower 8 as the heat source of the reboiler 12 in the middle section of the analysis tower 8. In the condensed oil heat exchanger 17, the stabilized gasoline exchanges heat with the condensed oil. Through multiple heat exchangers, the stabilized gasoline is gradually cooled and finally enters the air cooler 15. After cooling, a part of it is pressurized by the supplementary absorbent pump 18 and enters the top of the absorption tower 2 as a supplementary absorbent, and the other part is discharged from the absorption stabilization system as a product.

[0040] As an embodiment, the absorption and analysis system further includes a reflux tank 19 , the inlet end of the reflux tank 19 is connected to the top outlet end of the stabilization tower 13 , and the outlet end of the reflux tank 19 is connected to the top inlet end of the stabilization tower 13 .

[0041] like Figure 2 As shown, after the gas phase at the top of the stabilization tower 13 enters the reflux tank 19 for separation, the liquid phase is pumped out through the stabilization tower reflux pump, with one part returning to the top of the stabilization tower 13 as reflux and the other part as a product removal system.

[0042] A third reboiler 20 is provided at the bottom of the stabilization tower 13 .

[0043] The process flow of absorption and analysis system:

[0044] The rich gas coming out of the distillation part is compressed to 1.5-1.6MPaG by the compressor, the compressed gas is mixed with the gas at the top of the desorption tower, cooled to 60°C by the second cooler 5, and then mixed with the oil at the bottom of the absorption tower; after mixing, it is cooled to 40°C by the first cooler 6 and enters the condensed oil tank 1 to separate the rich gas and condensed oil. In order to prevent equipment corrosion, purified water is injected before and after the second cooler 5 for washing, and the washing water is discharged from the condensed oil tank 1 to the top of the distillation tower for secondary water injection washing.

[0045] The absorption tower 2 is located at the upper part of the analysis tower 8, with an operating pressure of 1.4MPaG and an average absorption temperature of 45°C. The rich gas from the condensed oil tank 1 enters the lower part of the absorption tower, and the crude gasoline from the distillation part is pumped in from the 30th, 25th and 14th layers respectively, and the supplementary absorbent is pumped in from the 35th layer to contact with the gas in countercurrent. In order to remove the heat released during the absorption process, two mid-section refluxes are provided in the middle of the absorption tower, which are pumped out from the 15th and 26th layers respectively, cooled by the cooler, and then returned to the top of the 14th and 25th layers of the tower. The saturated absorption oil at the bottom of the absorption tower is mixed with the compressed rich gas before entering the first cooler 6.

[0046] The lean gas from the top of the absorption tower enters the bottom of the reabsorption tower 21 and contacts with the light diesel as the absorbent in countercurrent flow to absorb the gasoline component carried by the lean gas. The pressure at the top of the reabsorption tower is 1.25 MPaG and the average temperature is 45°C. The dry gas discharged from the top of the reabsorption tower is sent to the dry gas desulfurization part, and the rich absorption oil at the bottom of the tower is returned to the distillation tower.

[0047] The condensed oil coming out of the condensed oil tank 1 is pressurized by the condensed oil pump 7 and then heat-exchanged with the heat exchanger 11 to 70°C, and enters the upper part of the desorption tower 8. The bottom temperature is about 110-130°C, and the top pressure is 1.6MPaG. The reboiler at the bottom of the desorption tower is heated by the reflux and lean absorption oil in the distillation tower 1. The gas at the top of the desorption tower is mixed with the compressed rich gas before it reaches the second cooler 5.

[0048] The deethanized gasoline at the bottom of the analysis tower 8 is heat-exchanged with the stabilized gasoline to 145-154°C and enters the stabilizer 13. The operating pressure at the top of the stabilizer 13 is 1.1MPaG, the bottom temperature is about 172°C, and the bottom reheater is heated by the reflux from the distillation tower 2; light components C4 and below are distilled from the top of the stabilizer 13, cooled to 40°C by wet air cooling condensation, and enter the reflux tank 19, one part of which is used as the top reflux, and the other part is sent to the desulfurization unit as a product; the stabilized gasoline at the bottom of the tower is first heat-exchanged with the deethanized gasoline, the material in the middle of the analysis tower, the desalted water and the condensed oil, and then cooled to 40°C by the air cooler 15, one part is pumped into the top of the absorption tower 2 by the supplementary absorbent pump 18 as a supplementary absorbent, and the other part is sent to the desulfurization unit or the delivery device as a product.

[0049] So far, the absorption and analysis system has completed the technical transformation of reducing the C3+ content of dry gas. After implementation, the C3+ content of dry gas in the unit has dropped from 3.5%v before the transformation to below 1.5%v, the product quality qualification rate is 100%, and the operation flexibility has increased.

[0050] The embodiment of the present invention provides a technical transformation for reducing the C3+ content of dry gas in a domestic 2.0Mt / a heavy oil catalytic cracking unit.

[0051] The preferred embodiments of the present invention are described in detail above in conjunction with the accompanying drawings, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

[0052] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0053] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. An absorption analysis system, characterized in that: The invention comprises a first cooler (6), a condensed oil tank (1), an absorption tower (2), a reflux in the first absorption tower (3), a reflux in the second absorption tower (4), a decomposition tower (8), a stabilization tower (13) and a reabsorption tower (21), wherein the outlet end of the first cooler (6) is connected to the inlet end of the condensed oil tank (1), the outlet end of the condensed oil tank (1) is respectively connected to the bottom inlet end of the absorption tower (2) and the top inlet end of the decomposition tower (8), the reflux in the first absorption tower (3) and the reflux in the second absorption tower (4) are respectively arranged in the middle of the absorption tower (2), the top outlet end of the absorption tower (2) is connected to the tower inlet end of the reabsorption tower (21), and the reflux in the first absorption tower (3) and the reflux in the second absorption tower (4) are respectively arranged in the middle of the absorption tower (2), and the top outlet end of the absorption tower (2) is connected to the tower inlet end of the reabsorption tower (21). The bottom inlet end of the absorption tower (2) is connected, the bottom outlet end of the absorption tower (2) is connected to the inlet end of the first cooler (6), the bottom outlet end of the analysis tower (8) is connected to the feed inlet end of the stabilization tower (13), the top outlet end of the analysis tower (8) is connected to the inlet end of the first cooler (6), and the bottom outlet end of the stabilization tower (13) is connected to the top of the absorption tower (2); wherein the top of the absorption tower (2) is provided with a crude gasoline pipeline for adding crude gasoline and a crude gasoline branch bypassing the crude gasoline pipeline, and the crude gasoline branch is respectively bypassed to the reflux (3) in the absorption tower one and the reflux (4) in the absorption tower two.

2. The absorption analysis system according to claim 1, characterized in that: It also includes a second cooler (5), the outlet end of the second cooler (5) is connected to the inlet end of the first cooler (6), and the bottom outlet end of the absorption tower (2) is connected between the first cooler (6) and the second cooler (5).

3. The absorption analysis system according to claim 1, characterized in that: The first reflux (3) of the absorption tower includes a first cooler (31) and a first reflux pump (32), the second reflux (4) of the absorption tower includes a second cooler (41) and a second reflux pump (42), and the crude gasoline branch is respectively connected to the outlet end of the first reflux pump (32) and the outlet end of the second reflux pump (42).

4. The absorption analysis system according to claim 1, characterized in that: A middle section reboiler (12) is provided in the middle section of the analytical tower (8).

5. The absorption analysis system according to claim 1, characterized in that: A reboiler is provided at the bottom of the analytical tower (8).

6. The absorption analysis system according to claim 1, characterized in that: A heat exchanger (11) is provided at the top of the analytical tower (8), and two ends of the heat exchanger (11) are connected to a jumper pipe, and a flow regulating valve is provided on the jumper pipe.

7. The absorption analysis system according to claim 1, characterized in that: It also includes a heat exchanger (14), wherein a first channel of the heat exchanger (14) is connected between the analysis tower (8) and the stabilization tower (13), and a second channel of the heat exchanger (14) is connected between the stabilization tower (13) and the absorption tower (2).

8. The absorption analysis system according to claim 1, characterized in that: It also includes a desalted water heat exchanger (16), a condensed oil heat exchanger (17) and an air cooler (15) which are sequentially connected to the stabilization tower (13) and the absorption tower (2).

9. The absorption analysis system according to claim 1, characterized in that: It also includes a reflux tank (19), the inlet end of the reflux tank (19) is connected to the tower top outlet end of the stabilization tower (13), and the outlet end of the reflux tank (19) is connected to the tower top inlet end of the stabilization tower (13).

10. The absorption analysis system according to claim 1, characterized in that: A third reboiler (20) is provided at the bottom of the stabilization tower (13).

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