CN107043636A - A kind of device and method of the three-phase regeneration of lighter hydrocarbons desulfurization alkali lye - Google Patents

Abstract

The invention discloses the device and method that a kind of three-phase of lighter hydrocarbons desulfurization alkali lye regenerates, including fiber film contactor and alkali liquid regeneration knockout drum；The internal interlude of fiber film contactor is filled with liquid membrane contactor fiber inner core, and internal top is provided with liquid distributor；The upper end side of fiber film contactor is connected to alkali lye filter, and alkali lye filter is circumscribed with compressed air hose and desulfurization alkali liquor pipe, and the top of fiber film contactor is circumscribed with circulation solvent pipe and low-sulfur solvent pipe for conveying solvent successively；Alkali liquid regeneration knockout drum point gas bag and offgas duct are circumscribed with the top of the tank body of alkali liquid regeneration knockout drum successively；It the advantage is that：Using three-phase mass transfer apparatus of the fiber film contactor as desulfurization alkali lye, the three-phases such as air, alkali lye, solvent are contacted fully in fiber film contactor, three-phase mass-transfer efficiency is high, chemical reaction and physical extraction process are all more thorough, contribute to three-phase quick separating simultaneously, mitigate three alternate mutual entrainments.

Description

A device and method for three-phase regeneration of light hydrocarbon desulfurization lye

technical field

The present invention relates to a method and device for regeneration reaction of lye produced by desulfurization of light hydrocarbons such as liquefied gas, C3, C4, C5, light gasoline, and air, and then extracting and removing disulfide with solvent; The invention relates to a device and method for three-phase regeneration of light hydrocarbon desulfurization alkali liquor.

Background technique

At present, most of the liquefied gas produced by refineries adopts MDEA amine liquid extraction technology to remove hydrogen sulfide, and sodium hydroxide alkali liquid extraction technology to remove mercaptans. The liquefied gas is separated into products such as C3, C4, C5, etc In order to meet the follow-up deep processing requirements, many companies use lye extraction technology to further desulfurize deeply, and some companies cut gasoline into light and heavy components. Light gasoline uses lye extraction technology to demercaptan, gasoline, naphtha , Condensate oil can also be desulfurized and deodorized by alkaline washing technology.

The following chemical reactions mainly exist in the desulfurization process of light hydrocarbon lye extraction:

RSH + NaOH → NaSR + H2O

H2S + 2NaOH → Na2S + 2H2O

The generated NaSR and Na2S are dissolved in the lye. With the prolongation of the desulfurization time, after the concentration of NaSR and Na2S in the lye reaches a certain level, the desulfurization ability of the lye decreases. In order to ensure that the total sulfur of the product is qualified, the lye needs to be replaced regularly.

In order to reduce the discharge of light hydrocarbon desulfurization waste caustic, light hydrocarbon caustic extraction and desulfurization devices are generally designed with desulfurized caustic oxidation regeneration facilities; In the presence of catalysts such as ammonium cyanine cobalt sulfonate and polytitanium cobalt, a certain flow of air passes through the lye, and the oxygen in the air reacts with sodium mercaptide and sodium sulfide in the lye. The main chemical reactions in this process are: :

2NaSR + 1/2 O2 + H2O → 2NaOH + RSSR

2Na2S + 2O2 + H2O → Na2S2O3 + 2NaOH

Na2S2O3 + 2O2 + 2NaOH → 2Na2SO4 + H2O

In order to improve the oxidation efficiency of lye, the lye oxidation basically adopts the oxidation tower method at present. The lye oxidation tower is divided into a packed tower and a bubble tower; the packed tower is filled with a certain volume of random packing or structured packing in the tower, and the lye The air and air are cut into small droplets and bubbles by the filler, thereby increasing the contact area of the gas-liquid two-phase; the bubble tower distributes the air into fine bubbles through the air distributor at the bottom of the tower, the smaller the bubbles, the smaller the contact area with the alkali solution bigger.

The RSSR (disulfide) produced by alkali oxidation is an oily organic matter, which is difficult to completely separate in the above alkali oxidation tower. If no effective and removal measures are taken, when the alkali is used for light hydrocarbon cycle desulfurization, disulfide It will be back-extracted into light hydrocarbon products, resulting in an increase in the total sulfur of light hydrocarbon products; therefore, disulfide separation equipment and solvent back-extraction equipment are designed in the existing alkali liquor regeneration process.

A company's patent 200710071004.9 liquefied gas sweetening lye oxidation regeneration method and device, patent 200710308071.8 an oily lye separation device and method, and patent 2012 2 0012653.8 a combined system for liquefied gas sweetening, the liquefied gas sweetening Alkali oxidation regeneration technology is the method of bubble tower oxidation and liquefaction separation of disulfide; the company's patent 201210276509.x a device and method for demercaptanization of gasoline light fractions and regeneration of lye, the liquefied gas sweetener lye Oxidation regeneration technology is bubble column oxidation and solvent back extraction to remove disulfide. The back extraction mass transfer equipment adopts fiber liquid membrane reactor.

A company's patent 200910250279.8 is a liquid hydrocarbon sweetening technology capable of deep removal of total sulfur. The liquefied gas sweetening alkali liquor oxidation regeneration technology is the method of packing tower oxidation and solvent back extraction to remove disulfide. The packed tower enters the lye, solvent and air at the same time, the packing is an activated carbon bed layer solidly loaded with sulfonated cyanine cobalt catalyst, and the three-phase mixture enters the separation tank for three-phase separation. The company's patent 200710123546.6 is a combined process for sweetening gasoline, which is the popularization and application of the above patent in sweetening gasoline light fractions.

The mass transfer equipment involved in the above-mentioned patent lye oxidation regeneration process is basically lye oxidation tower, solvent back extraction fiber liquid film contactor and settling separation tank. The process flow is relatively complicated, the number of equipment is large, and the investment in device construction is relatively high; In addition, in the above-mentioned patent, the technology of solvent back extraction to remove disulfide is adopted. After back extraction, a small amount of lye will inevitably be entrained in the solvent, and there is no mention of removing the lye entrained in the back extraction solvent. If it is directly sent to solvent hydrodesulfurization, it is easy to cause poisoning of the catalyst of the hydrogenation unit, which may cause heavy losses.

Contents of the invention

Aiming at the deficiencies of the prior art, the present invention provides a method that utilizes the characteristics of high-efficiency mass transfer of the fiber liquid film contactor, and completes air catalytic oxidation, solvent back extraction to remove disulfide and three-phase separation in one step in the fiber liquid film contactor equipment. A device and method for three-phase regeneration of a light hydrocarbon desulfurization alkali liquor in three processes.

In order to solve the above technical problems, the present invention is solved by the following technical scheme: a device and method for three-phase regeneration of light hydrocarbon desulfurization alkali liquor, including vertical fiber liquid membrane contactor and horizontal alkali liquor regeneration separation tank; the middle section of the fiber liquid film contactor is filled with a liquid film contactor fiber inner core, and the top end of the body is provided with a liquid distributor; the upper end of the fiber liquid film contactor is connected to an alkali filter, and the The lye filter is externally connected with a compressed air pipe for transporting air and a desulfurization lye pipe for transporting lye after desulfurization of light hydrocarbons dissolved with catalysts such as sulfonated cyanine cobalt, and the top of the fiber liquid membrane contactor is sequentially There are circulating solvent pipes and low-sulfur solvent pipes for solvent delivery on the outside, air, lye, and solvent are mixed in the liquid distributor and then enter the fiber core of the liquid film contactor; the tank of the lye regeneration separation tank The top of the body cavity is provided with a coalescing plate of the lye regeneration separation tank, and the bottom of the tank inner cavity is provided with an lye regeneration separation tank partition, both of which are arranged in parallel, and the lye regeneration separation tank coalescing plate is separated from the lye regeneration The tank partition divides the tank body into an area to be separated and an area that has been separated; the top of the tank in the area to be separated is equipped with a fiber liquid film contactor and fixed with a flange; the top of the tank in the separated area is connected with lye in turn The regeneration separation tank is divided into a gas bag and an exhaust pipe; the bottom of the tank body of the to-be-separated area is externally connected with an alkali liquor regeneration separation tank liquid separation bag, and the alkali liquor regeneration separation tank liquid separation bag is externally connected with a regeneration alkali liquor pipe, a regeneration alkali Liquid pump and regenerated lye outlet device pipe; the bottom of the tank body in the separated area is externally connected with a back-extraction solvent pipe, and the back-extraction solvent pipe is connected with the circulating solvent pipe through a solvent circulation pump.

It also includes a water-washing separation tank, the solvent in the circulating solvent pipe passes through the sulfur-containing solvent pipe, the Venturi mixer and the water-washing solvent pipe and then injects it into the water-washing separation tank from the top; the tank top of the water-washing separation tank is also A fresh water pipe and a sulfur-containing solvent outlet pipe are externally connected; a water-washing separation tank liquid separation bag is externally connected to the bottom of the tank; a circulating water pipe and an alkaline waste water pipe are externally connected to the water-washing separation tank liquid separation bag, and the circulating water pipe and the Venturi Mixer butt.

A method for three-phase regeneration of light hydrocarbon desulfurization lye, the steps are as follows:

a. Two-phase mixing step: the air flowing out from the compressed air pipe is mixed with the light hydrocarbon desulfurized alkali liquor flowing out from the desulfurized alkali liquor pipe in the alkali liquor filter, and the alkali liquor after light hydrocarbon desulfurization contains sodium mercaptide, sodium sulfide and catalyst Sulfonated titanium cyanine.

b. Three-phase mixing step: the solvent flowing out from the circulating solvent pipe is mixed with the air and lye in step a in the liquid distributor.

c. Oxidation reaction step: three phases such as air, lye, and solvent are fully contacted and reacted in the fiber liquid membrane contactor. Oxygen in the reaction reacts to generate sodium hydroxide and disulfide, sodium thiosulfate, sodium sulfate and other substances.

d. Precipitation and separation step: Precipitation and separation are carried out in the lye regeneration separation tank, the alkali and salt substances are dissolved in the lye, and flow out through the liquid separation bag of the lye regeneration separation tank; disulfide is dissolved in the solvent, and the The last solvent pipe flows out; the remaining unreacted gas phase in the air is exhausted from the gas bag at the top of the alkali liquor regeneration separation tank in the form of tail gas.

e. Solvent circulation and replenishment steps: the recirculation solvent flowing out of the solvent pipe after stripping is pressurized by the solvent circulation pump, mixed with the nascent solvent from the low-sulfur solvent pipe, and then injected into the fiber liquid film contactor through the circulation solvent pipe .

f. Water washing and separation step: the recirculated solvent flowing out of the solvent pipe after back extraction passes through the sulfur-containing solvent pipe, Venturi mixer and water washing solvent pipe into the water washing and separation tank for water washing and separation.

g. Water circulation step: the water in the washing separation tank passes through the liquid separation bag of the washing separation tank, the circulating water pipe, the Venturi mixer and the washing solvent pipe successively, and then injects into the washing separation tank from the top.

In step a, the concentration of sodium sulfide in the lye after light hydrocarbon desulfurization is 0.03-0.19%wt, the concentration of sodium mercaptide is 0.43-1.22%wt, the flow rate of lye is 20-50Kg/h, and the operating temperature is 30-65°C; Air flow 3-4Nm3/h.

In step b, the circulation flow rate of solvent gasoline is 50-60Kg/h, and the supplementary flow rate of solvent is 25-40Kg/h.

Compared with the prior art, the present invention has the following beneficial effects: the fiber liquid film contactor is used as the three-phase mass transfer equipment for the desulfurization alkali solution, and the three phases such as air, alkali solution and solvent are fully contacted in the fiber liquid film contactor. The phase mass transfer efficiency is high, and the chemical reaction and physical extraction process are more thorough. At the same time, it is helpful for the rapid separation of the three phases and reduces the mutual entrainment between the three phases. The content of sodium mercaptide and sodium sulfide in the regenerated lye can be oxidized to below 100ppm The ether content can also be removed to less than 100ppm, and the content of alkaline substances in the back-extraction solvent can be controlled below 1ppm after washing with water; it has good regeneration effect of desulfurization lye, very low content of lye entrained in the back-extraction solvent, and saves equipment investment , Simple process and so on.

Description of drawings

Fig. 1 is the process flow diagram of the embodiment of the present invention.

detailed description

Below in conjunction with accompanying drawing 1 and specific embodiment, the present invention is described in further detail: mark as follows among the figure: fiber liquid film contactor 1, liquid distributor 2, liquid film contactor fiber inner core 3, lye regeneration separation tank 4, waiting Separation zone 41, separated zone 42, lye regeneration separation tank gas distribution bag 5, lye regeneration separation tank coalescence plate 6, lye regeneration separation tank partition 7, lye regeneration separation tank liquid separation bag 8, lye Filter 9, regenerated lye pump 10, solvent circulation pump 11, Venturi mixer 12, washing separation tank 13, water separation tank separation bag 14, desulfurization lye pipe 15, regenerated lye pipe 16, regenerated lye outlet Device pipe 17, compressed air pipe 18, exhaust pipe 19, low-sulfur solvent pipe 20, circulating solvent pipe 21, back-extraction solvent pipe 22, sulfur-containing solvent pipe 23, washing solvent pipe 24, sulfur-containing solvent outlet pipe 25 , fresh water pipe 26, circulating water pipe 27, alkaline waste water pipe 28.

A device and method for three-phase regeneration of light hydrocarbon desulfurization alkali liquor, comprising a vertical fiber liquid membrane contactor 1 and a horizontal alkali liquor regeneration separation tank 4; the middle section of the fiber liquid membrane contactor 1 is filled with The fiber inner core 3 of the liquid film contactor is provided with a liquid distributor 2 at the top of the body; the upper end of the fiber liquid film contactor 1 is connected with a lye filter 9, and the lye filter 9 is externally connected with a compressed air pipe 18 for conveying air And the desulfurization lye pipe 15 that is used to transport the lye after desulfurization of light hydrocarbons dissolved with catalysts such as sulfonated cyanine cobalt, the top of the fiber liquid membrane contactor 1 is successively connected with a circulating solvent pipe 21 and a low-sulfur lye for transporting solvent. Solvent pipe 20, air, lye, and solvent are mixed in the liquid distributor 2 and then enter the fiber core 3 of the liquid film contactor; the top of the tank inner cavity of the lye regeneration separation tank 4 is provided with a coalescing plate 6 of the lye regeneration separation tank , the bottom of the tank inner cavity is provided with an alkali regeneration separation tank partition 7, and the two are arranged in parallel. The coalescence plate 6 of the alkali regeneration separation tank and the alkali liquor regeneration separation tank partition 7 divide the tank body into a separation zone 41 and an already separated area. Separation zone 42.

A fiber liquid film contactor 1 is arranged on the top of the tank body in the area to be separated 41 and fixed with a flange. The bottom of the tank body in the area to be separated 41 is externally connected with an alkali regeneration separation tank liquid separation bag 8, and the alkali liquid regeneration separation tank liquid separation bag 8 is in turn Externally connected with regenerated lye pipe 16, regenerated lye pump 10 and regenerated lye outlet device pipe 17.

The top of the tank body of the separated area 42 is connected with an alkali liquor regeneration separation tank sub-gas bag 5 and the tail gas pipe 19 successively; It communicates with the circulation solvent pipe 21 through the solvent circulation pump 11 .

Also include washing separation tank 13, the solvent in the circulating solvent pipe 21 passes through sulfur-containing solvent pipe 23, Venturi mixer 12 and water washing solvent pipe 24 successively and injects in the water washing separation tank 13 from the top; Also externally connected with fresh water pipe 26 and sulfur-containing solvent outlet device pipe 25; externally connected with water washing separation tank liquid separation bag 14 at the bottom of the tank; Venturi mixer 12 docked.

The light hydrocarbon desulfurization lye mentioned in this application includes liquefied gas, the products after gas separation of liquefied gas such as C3, C4, C5, and the lye produced by light hydrocarbon desulfurization and desulfurization of light hydrocarbons such as light gasoline, and also Including lye produced by desulfurization and deodorization of gasoline, naphtha, chemical light oil, condensate and other light oil products.

A method for three-phase regeneration of light hydrocarbon desulfurization lye, comprising the following: 1), the air flowing out from the compressed air pipe 18 and the light hydrocarbon desulfurization that is dissolved with catalysts such as sulfonated cyanine cobalt and the like that flow out from the desulfurization lye pipe 15 After the lye is mixed in the coarse step of the lye filter 9, it is mixed again in the liquid distributor 2 with the solvent flowing out from the circulating solvent pipe 21, and then enters the fiber liquid membrane contactor 1 to react; air, lye, solvent The three phases are fully contacted in the fiber liquid membrane contactor. Under the action of catalysts such as sulfonated titanium cyanine cobalt, the sodium mercaptide and sodium sulfide in the lye contact with the oxygen in the air and react chemically to form sodium hydroxide and Disulfide, sodium thiosulfate, sodium sulfate and other substances; alkali and salt substances are dissolved in the lye, disulfide is dissolved in the solvent, and the remaining unreacted gas phase in the air is released from the top of the lye regeneration separation tank in the form of tail gas Gas distribution bag discharge device, due to the different polarity and certain density difference, the solvent and lye are stratified and stay in the upper layer of the lye regeneration separation tank, overflowing the separator in the separation tank and flowing to the side of the solvent phase, through the solvent cycle The pump is pressurized, part of the solvent is mixed with supplementary low-sulfur solvent to form a circulating solvent, and enters the fiber liquid film contactor from the top of the contactor, and the rest of the solvent enters the solvent water elution desulfurization facility, and the regenerated lye is separated from the bottom of the lye regeneration separation tank The lye containing lye is discharged from the outlet, and is sent to light hydrocarbon desulfurization after being pressurized by the regenerated lye pump. The coalescence plate in the lye regeneration separation tank helps to improve the three-phase separation efficiency and reduce the mutual entrainment between the three phases.

2): partly from 1) after back extraction, the sulfur-containing solvent and circulating water are mixed through a Venturi mixer and enter the washing tank. The lye entrained in the solvent is a polar substance, which is easily dissolved in water. Due to the polarity Different and there is a certain density difference, the solvent and alkaline water layer and stay in the upper layer of the separation tank, from the outlet of the solvent on the top of the separation tank, it is sent to the raw material tank of the solvent hydrogenation device by pressure, and the alkaline water is sent from the liquid separation bag at the bottom of the separation tank The water is discharged from the outlet. Under the suction of the Venturi mixer, part of the water enters the mixer, and part of the water is sent to the alkaline wastewater treatment device by self-pressure. Through the flow control, the fresh water inlet at the top of the washing tank is supplemented and discharged at the same time. Water; the content of alkaline substances entrained in the sulfur-containing solvent after back extraction can be controlled by changing the amount of water. The mixing of sulfur-containing solvent and circulating water after stripping can also be realized by water washing pumps and other types of mixers.

Embodiment 1: the desulfurization alkali liquor is collected from a liquid hydrocarbon desulfurization device of a certain company, and the method of the present invention is adopted to carry out the experiment, and the experimental results are as follows: the liquid hydrocarbon desulfurization alkali liquor consists of: sodium sulfide concentration 0.19%wt, sodium mercaptide concentration 1.22%wt, The flow rate of the experimental lye is 20Kg/h, the operating temperature is 50-65°C, the content of the sulfonated cyanine cobalt catalyst is 160-200ppm; the compressed air flow rate is 3.5-4Nm3/h; the solvent gasoline circulation flow rate is 60Kg/h, and the solvent replenishment flow rate is 40Kg/h; The content of sodium sulfide in the regenerated lye cannot be detected, the content of sodium mercaptide is 27ppm, the content of disulfide is 45ppm, and the content of alkaline substances in the back extraction solvent after washing is 0.75ppm.

Embodiment 2: the desulfurization alkali liquor is collected from a liquid hydrocarbon desulfurization device of a certain company, and the method of the present invention is adopted to carry out the experiment, and the experimental results are as follows: the liquid hydrocarbon desulfurization alkali liquor consists of: sodium sulfide concentration 0.03%wt, sodium mercaptide concentration 0.43%wt, The flow rate of experimental lye is 50Kg/h, the operating temperature is 30-45°C, the content of sulfonated titanium cyanine cobalt catalyst is 100-130ppm; the flow rate of compressed air is 3-3.5Nm3/h; the circulation flow rate of solvent gasoline is 50Kg/h, and the flow rate of solvent replenishment is 25Kg/h The content of sodium sulfide in the regenerated lye cannot be measured, the content of sodium mercaptide is 13ppm, the content of disulfide is 39ppm, and the content of alkaline substances in the back extraction solvent after washing is 0.55ppm.

Claims (4)

1. A device and method for three-phase regeneration of light hydrocarbon desulfurization lye, comprising a vertical fiber liquid membrane contactor (1) and a horizontal lye regeneration separation tank (4); characterized in that: The middle section of the fiber liquid film contactor (1) is filled with the inner fiber core (3) of the liquid film contactor, and the top of the body is provided with a liquid distributor (2); the upper end of the fiber liquid film contactor (1) is connected to There is a lye filter (9), and the lye filter (9) is externally connected with a compressed air pipe (18) for transporting air and a desulfurized alkali for transporting light hydrocarbons dissolved in catalysts such as sulfonated cyanine cobalt. The desulfurization alkali solution pipe (15) of the liquid, the top of the fiber liquid film contactor (1) is connected externally in turn with a circulating solvent pipe (21) and a low-sulfur solvent pipe (20) for transporting solvent, air, alkali solution, solvent After mixing in the liquid distributor (2), it enters the fiber inner core (3) of the liquid film contactor; the top of the tank inner cavity of the lye regeneration separation tank (4) is provided with an lye regeneration separation tank for coalescence plate (6), the bottom of the tank inner cavity is provided with an alkali regeneration separation tank partition (7), the two are arranged in parallel with a gap in the middle, the coalescing plate (6) of the alkali regeneration separation tank and the alkali regeneration The separator of the separation tank (7) divides the tank into the area to be separated (41) and the separated area (42); the top of the tank of the area to be separated (41) is equipped with a fiber liquid film contactor (1) and a flange Fixed, the bottom of the tank body is externally connected with the liquid separation package (8) of the lye regeneration separation tank, and the liquid separation package (8) of the lye regeneration separation tank is connected with the regenerated lye pipe (16) and the regenerated lye pump (10) in turn and regenerated lye outlet device pipe (17); the top of the tank body of the separated area (42) is successively connected with an lye regeneration separation tank sub-gas bag (5) and an exhaust pipe (19), and the separated area ( 42) is externally connected to the back-extraction solvent pipe (22) at the bottom of the tank, and the back-extraction solvent pipe (22) is connected to the circulation solvent pipe (21) through the solvent circulation pump (11). 2. The device and method for three-phase regeneration of light hydrocarbon desulfurization lye according to claim 1, characterized in that: it also includes a washing separation tank (13), and the solvent in the circulating solvent pipe (21) Sequentially pass through the sulfur-containing solvent pipe (23), Venturi mixer (12) and water washing solvent pipe (24) and then inject it into the water washing separation tank (13) from the top; the tank top of the water washing separation tank (13) is also A fresh water pipe (26) and a sulfur-containing solvent outlet pipe (25) are externally connected; a water separation tank liquid separation package (14) is externally connected to the bottom of the tank, and the water separation tank liquid separation package (14) is externally connected to a circulating water pipe (27) and an alkaline waste water pipe (28), the circulating water pipe (27) is docked with the Venturi mixer (12). 3. a method for the three-phase regeneration of light hydrocarbon desulfurization lye, its steps are as follows: a. Two-phase mixing step: the air flowing out from the compressed air pipe is mixed with the light hydrocarbon desulfurized alkali liquor flowing out from the desulfurized alkali liquor pipe in the alkali liquor filter, and the alkali liquor after light hydrocarbon desulfurization contains sodium mercaptide, sodium sulfide and catalyst Sulfonated titanium cyanine; b. Three-phase mixing step: the solvent flowing out from the circulating solvent pipe is mixed with the air and lye in step a in the liquid distributor; c. Oxidation reaction step: three phases such as air, lye, and solvent are fully contacted and reacted in the fiber liquid membrane contactor. Oxygen in the reaction reacts to generate sodium hydroxide and disulfide, sodium thiosulfate, sodium sulfate and other substances; d. Precipitation and separation step: Precipitation and separation are carried out in the lye regeneration separation tank, the alkali and salt substances are dissolved in the lye, and flow out through the liquid separation bag of the lye regeneration separation tank; disulfide is dissolved in the solvent, and the The rear solvent pipe flows out; the remaining unreacted gas phase in the air is exhausted from the top part of the gas bag of the alkali liquor regeneration separation tank in the form of tail gas; e. Solvent circulation and replenishment steps: the recirculation solvent flowing out of the solvent pipe after stripping is pressurized by the solvent circulation pump, mixed with the nascent solvent from the low-sulfur solvent pipe, and then injected into the fiber liquid film contactor through the circulation solvent pipe ; f. Water washing separation step: the recirculation solvent flowing out from the solvent pipe after back extraction enters the water washing separation tank through the sulfur-containing solvent pipe, Venturi mixer and water washing solvent pipe for water washing and separation; g. Water circulation step: the water in the washing separation tank is injected into the washing separation tank from the top after passing through the liquid separation bag of the washing separation tank, the circulating water pipe, the Venturi mixer and the washing solvent pipe successively; The method for the three-phase regeneration of a kind of light hydrocarbon desulfurization lye as claimed in claim 3, is characterized in that: In step a, the concentration of sodium sulfide in the lye after light hydrocarbon desulfurization is 0.03-0.19%wt, the concentration of sodium mercaptide is 0.43-1.22%wt, the flow rate of lye is 20-50Kg/h, and the operating temperature is 30-65°C; Air flow 3-4Nm3/h. 4. the method for the three-phase regeneration of a kind of light hydrocarbon desulfurization lye as claimed in claim 3, is characterized in that: in step b, solvent gasoline circulation flow rate 50-60Kg/h, solvent make-up flow rate 25-40Kg/h .