A method for removing hydrogen sulfide from liquid phase products of non-thermal stripping enhanced hydrogenation

Abstract

The present invention relates to a non-thermal stripping enhanced hydrogenation liquid phase product desulfurization method in the field of petroleum refining technology, comprising the following steps: step one: injecting the hydrogenation liquid phase product from the low fraction container into the bottom of the stripping tower; step two: using hydrogen as the stripping medium, injecting the hydrogen into the negative pressure cavity of the stripping unit in the stripping tower, the hydrogen in the negative pressure cavity of the stripping unit attracts the hydrogenation liquid phase product through the venturi, so that the hydrogenation liquid phase product and the hydrogen flow upward to the mixing cavity of the stripping unit in parallel. The present invention adopts the negative pressure effect of the fluid, utilizes the special flow field structure of the hydrogenation liquid phase product to form a negative pressure area, sucks in and mixes the carrier gas, is in a fully mixed flow state locally, and is in a countercurrent flow state macroscopically, only consumes the static pressure of the liquid phase fluid, does not add an additional circulation system, and reduces the use cost.

Description

Technical Field

[0001] The invention relates to the technical field of petroleum refining, in particular to a method for desulfurizing hydrogen from a liquid phase product of non-thermal stripping enhanced hydrogenation. Background Art

[0002] During the petroleum hydrogenation reaction process, sulfur element is converted into hydrogen sulfide. The hydrogen sulfide in the gas phase product is removed through the circulating hydrogen desulfurization system. The presence of hydrogen sulfide in the liquid phase product affects the corrosion of the oil. In order to ensure that the corrosion of the final oil meets the national standards, it needs to be separated through the stripping process.

[0003] In the traditional method, medium-pressure steam or low-pressure steam is used as the carrier gas, and the steam itself is kept from condensing. The carrier gas contacts the liquid product, and during the contact process, hydrogen sulfide is transferred from the liquid phase to the carrier gas phase to complete the stripping mass transfer. In the dehydrogen sulfide stripping tower, the removal of hydrogen sulfide from oil products is a typical gas-liquid mass transfer process. The main factors affecting the hydrogen sulfide separation performance include the raw material inlet tower temperature, the tower top reflux temperature, the tower top reflux amount, the tower top pressure, the raw material feed position, the number of tower plates, the stripping steam consumption, etc.

[0004] The traditional stripping equipment is a steam stripping tower. In this process, the countercurrent relative movement of gas and liquid is limited by the effect of the gravity field, and the gas-liquid mass transfer efficiency is low. In order to reduce the hydrogen sulfide content in the liquid phase as much as possible, the steam injection amount is usually increased, resulting in excessive energy consumption in the factory. Further increasing the use of steam will aggravate the problem of water in the bottom oil of the steam stripping tower and serious corrosion on the top of the tower. The top pressure of the hydrogen sulfide stripping tower needs to be slightly greater than the pressure of the desulfurization fuel gas pipeline network of the entire plant. In order to control the hydrogen sulfide content of the bottom oil, the hydrogen sulfide stripping tower usually needs to consume more hot carrier gas, but the color and stability of the bottom oil may deteriorate due to thermal decomposition. Heating blindly can only bring more high energy consumption, high corrosion, low quality and other problems; for example, the Chinese patent with application number 201210139179.X discloses a diesel hydrogenation device and production process, which uses 1.0MPa superheated steam as the stripping medium. The steam is in a non-condensable state; Chinese patent application number 201610480503.2 provides a hydrocracking product fractionation system and fractionation method, which uses a multi-stage heating and multi-stage flash evaporation method to separate hydrogen sulfide from the liquid phase product, but still presents high energy consumption characteristics; Chinese patent application number 200710027561.0 provides a diesel hydrorefining fractionation method and device, which uses steam to strip hydrogen sulfide, and must be dehydrated with high precision to prevent corrosion and product quality problems caused by water.

[0005] There are many reports in China on reducing steam energy consumption in the process of desulfurization of hydrogenated liquid products. Most of the literature is based on energy-saving principles such as thermal network optimization and condensation heat recycling to reduce heat loss. The Chinese patent application number 201310500685.1 provides a process flow and application of a gasoline and diesel hydrofining unit and a method for gasoline and diesel hydrofining, which effectively utilizes the heat of the bottom product of the product fractionation tower of the gasoline and diesel hydrofining unit, greatly reducing the cooling load of the product fractionation tower and the hydrogen sulfide stripping tower. However, the use of steam has not been completely eliminated, and problems such as high energy consumption, high corrosion, and low quality have not been fundamentally solved.

[0006] At present, the most mainstream hydrogenation technology in China adopts a circulating hydrogenation process, which is usually used to remove impurities such as sulfur in the raw materials. However, there is a large amount of hydrogen used in the existing process flow, which is not conducive to energy saving and has cost issues. For example, Chinese invention patent 200910157466.1 provides a method for removing mercaptans from gasoline, using inert gas or steam, which is directly injected into the reactor to achieve the removal of hydrogen sulfide. The mercaptan sulfur content in the gasoline product is less than 3μg / g; Chinese invention patent 201410062626.5 provides a method for liquid-phase circulating hydrogenation reforming of high-nitrogen catalytic cracking diesel. The product coming out of the top of the reactor enters a hydrogen stripping separator, and an appropriate amount of hydrogen is introduced into the lower part of the separator to strip out ammonia and hydrogen sulfide. The by-products hydrogen sulfide and ammonia are discharged from the reaction system; Chinese invention patent 202011070236.4 provides an environmentally friendly high-pressure steam stripping and impurity removal method before the second-stage hydrogenation of aromatic oil, which uses circulating hydrogen as a carrier gas to blow off and separate hydrogen sulfide under high pressure conditions; Chinese invention patent 201420725667.3 provides a hydrogen sulfide removal device for low-pressure separation of diesel, which uses hydrogen as a carrier gas and injects the hydrogen carrier gas into the original stripping tower. The use of this device can remove hydrogen sulfide from diesel without making the diesel contain water, and can also save heat energy.

[0007] To this end, we provide a non-thermal stripping enhanced hydrogenation liquid product desulfurization method which can enhance the mass transfer efficiency of hydrogen stripping and reduce the amount of hydrogen used. Summary of the invention

[0008] The object of the present invention is to provide a method for dehydrogenating liquid phase products by non-thermal stripping enhanced hydrogenation in order to solve the above problems.

[0009] The present invention achieves the above-mentioned purpose through the following technical solutions:

[0010] A method for dehydrogenating a liquid phase product of hydrogenation by non-thermal stripping enhancement comprises the following steps:

[0011] Step 1: injecting the hydrogenated liquid phase product from the low fraction container into the bottom of the stripping tower;

[0012] Step 2: Using hydrogen as the stripping medium, injecting hydrogen into the negative pressure cavity of the stripping unit in the stripping tower, the hydrogen in the negative pressure cavity of the stripping unit attracts the hydrogenation liquid phase product through the venturi, so that the hydrogenation liquid phase product and the hydrogen flow upward in parallel to the mixing cavity of the stripping unit;

[0013] Step 3: The hydrogenated liquid phase product entering the stripping unit mixing chamber is separated from the hydrogen. The separated hydrogenated liquid phase product and hydrogen enter the cyclonic mass transfer component located at the top of the stripping unit mixing chamber to flow in a cyclonic flow, and then enter the stripping unit separation chamber above the stripping unit mixing chamber;

[0014] Among them, the hydrogenation liquid phase product and hydrogen present a fully mixed flow state in the cyclone cavity of the cyclone mass transfer component;

[0015] Step 4: The hydrogenated liquid phase product entering the separation chamber of the stripping unit is separated from the hydrogen, and the separated hydrogen is discharged from the stripping unit separation chamber to the outside of the stripping tower, and the separated hydrogenated liquid phase product flows out from the top outlet of the stripping tower to the downstream;

[0016] Among them, the volume flow ratio of hydrogen to hydrogenated liquid products is 0.25-5; the liquid level of hydrogenated liquid products in the mixing chamber of the stripping unit is located between the liquid inlet and the gas inlet of the cyclone mass transfer component, and the liquid level of hydrogenated liquid products in the separation chamber of the stripping unit is higher than the venturi liquid inlet.

[0017] Preferably, the inner cavity of the stripping tower is provided with N stripping units along its height direction, and the N stripping units are, from bottom to top, the first stripping unit, the second stripping unit, ..., the Nth stripping unit. In the step 2, hydrogen is injected into the negative pressure cavity of the Nth stripping unit in the stripping tower, and finally discharged from the separation cavity of the first stripping unit to the outside of the stripping tower, and the hydrogen discharged from the separation cavity of the Mth stripping unit enters the negative pressure cavity of the M-1th stripping unit through a pipeline, wherein N≥2, 1<M≤N; macroscopically, the hydrogen and the hydrogenation liquid phase product are in countercurrent contact.

[0018] Preferably, the hydrogen pressure in the negative pressure cavity of the first stripping unit is less than the hydrogen pressure in the separation cavity of the Nth stripping unit, and the pressure difference is 1 to 5 kPa; the hydrogen Reynolds number in the pipeline is not greater than 300.

[0019] Preferably, the swirl mass transfer component has a swirl mass transfer component swirl cavity inside, a swirl mass transfer component neck cavity is provided at the upper end of the swirl mass transfer component swirl cavity, a swirl mass transfer component outlet connected to the stripping unit separation cavity is provided at the upper end of the swirl mass transfer component neck cavity, a swirl mass transfer component gas inlet is evenly arranged around the swirl mass transfer component for supplying hydrogen to the swirl mass transfer component swirl cavity, a swirl mass transfer component liquid inlet is also evenly arranged around the swirl mass transfer component of the stripping unit for supplying hydrogenation liquid phase product to the swirl mass transfer component swirl cavity, and the swirl mass transfer component liquid inlet is located below the swirl mass transfer component gas inlet.

[0020] Preferably, the density of the hydrogenated liquid phase product is 600 to 890 kg / m3, and the viscosity of the hydrogenated liquid phase product is 0.01 to 0.5 cP.

[0021] Preferably, the Venturi has a tapering section with a tapering angle of 2 to 6° at the lower side corresponding to the hydrogen inlet, and the Venturi has a tapering section with a tapering angle of 5 to 16° at the upper side corresponding to the hydrogen inlet, and the small end of the tapering section is sealed and abutted against the small end of the tapering section.

[0022] Preferably, the Venturi throat flow velocity is 5 to 20 m / s;

[0023] The venturi throat velocity is equal to the total volume flow of gas and liquid entering the venturi divided by the venturi throat area.

[0024] Preferably, the Reynolds number of the hydrogenated liquid phase product of the cyclonic mass transfer component is 3000-10000.

[0025] The liquid Reynolds number expression of the swirl mass transfer component is:

[0026] Where d is the equivalent diameter of the liquid inlet of the swirl mass transfer component, u is the average liquid velocity at the liquid inlet of the swirl mass transfer component, ρ L is the liquid density, μ L is the liquid viscosity;

[0027] The basic principle of cyclonic mass transfer components is that both gas and liquid are injected from the tangential inlet of the side wall of the cyclonic cavity to form a gas-liquid cyclonic flow. Since the liquid must move to the central neck cavity, the liquid is a continuous phase. The gas is cyclonic while penetrating the liquid continuous phase. Under the centrifugal acceleration conditions of the cyclonic flow, the relative slip speed of the gas and liquid is accelerated. According to the surface renewal mass transfer theory, gas-liquid equilibrium can be achieved in a very short time, reflecting the characteristics of enhanced mass transfer.

[0028] The formation of the swirl field of the swirl mass transfer component includes two factors, one is the push of gas, the other is the push of liquid. When the gas-liquid ratio is less than 0.6, it mainly relies on the push of liquid. When the gas-liquid ratio is greater than or equal to 0.6, it mainly relies on the push of gas.

[0029] Therefore, it is further configured that the velocity at the liquid inlet of the cyclonic mass transfer component is 1-5.5 m / s, and the velocity at the hydrogen inlet of the cyclonic mass transfer component is 2-10 m / s.

[0030] Preferably, the swirl diameter of the swirl mass transfer component is 20 to 200 mm;

[0031] Among them, when the velocity at the liquid inlet of the swirl mass transfer component is 1-2.5m / s, the swirl diameter of the swirl mass transfer component is 20-60mm; when the velocity at the liquid inlet of the swirl mass transfer component is 2.5-4m / s, the swirl diameter of the swirl mass transfer component is 60-100mm; when the velocity at the liquid inlet of the swirl mass transfer component is 4-5.5m / s, the swirl diameter of the swirl mass transfer component is 100-200mm.

[0032] The beneficial effects are:

[0033] 1. The present invention adopts the negative pressure effect of fluid and utilizes the special flow field structure of hydrogenation liquid phase product to form a negative pressure area, inhales and mixes the carrier gas, forms a fully mixed flow state locally, and forms a countercurrent flow state macroscopically, only consumes the static pressure of liquid phase fluid, does not add an additional circulation system, and reduces the use cost;

[0034] 2. Although the implementation of the present invention increases the cost of hydrogen recycling and regeneration, it eliminates the steam consumption, acidic water treatment, tower top cooling water consumption, power consumption of moving equipment, etc. of the steam stripping technology. After comprehensive consideration and calculation, the hydrogen stripping route with enhanced mass transfer of the present invention reduces the cost of hydrogen sulfide separation by 30% compared with the steam stripping technology;

[0035] 3. Due to the arrangement of the cyclonic mass transfer component, the present invention enables hydrogen and the hydrogenated liquid phase product from the low fraction container to enter from the corresponding cyclonic mass transfer component gas inlet and cyclonic mass transfer component liquid inlet, respectively, to form a gas-liquid cyclonic flow. Since the hydrogenated liquid phase product must move to the necking cavity of the cyclonic mass transfer component, the hydrogenated liquid phase product is a continuous phase. The hydrogen is performing a cyclonic motion while penetrating the continuous phase of the hydrogenated liquid phase product. Moreover, under the cyclonic centrifugal acceleration condition, the relative slip speed of hydrogen and the hydrogenated liquid phase product is accelerated. According to the surface renewal mass transfer theory, it can be Gas-liquid equilibrium is achieved in a very short time, reflecting the characteristics of enhanced mass transfer, thereby accelerating the transfer of hydrogen sulfide in the hydrogenated liquid phase product to hydrogen and being carried away by hydrogen, thereby improving the function of removing hydrogen sulfide in the hydrogenated liquid phase product. Therefore, compared with the existing technology, the quality of the product after removing hydrogen sulfide from the hydrogenated liquid phase product can be qualified by reducing the use of hydrogen, thereby achieving the function of reducing hydrogen consumption and achieving energy saving. It is also possible to reduce the volume of the hydrogen desulfurization stripping tower in the hydrogen route while ensuring the quality of the product after removing hydrogen sulfide from the hydrogenated liquid phase product.

[0036] The additional technical features and advantages of the present invention will be more clearly explained in the following description, or can be understood through the specific practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present invention but do not constitute a limitation of the present invention. In the accompanying drawings:

[0038] Figure 1 It is a flow chart of desulfurization of hydrogen by steam route in the prior art;

[0039] Figure 2 is a flow chart of dehydrogen sulfide using the hydrogen route of the present invention;

[0040] Figure 3 It is a schematic structural diagram of a non-thermal stripping enhanced hydrogenation liquid phase product desulfurization hydrogenation device in the present invention;

[0041] Figure 4 It is a schematic structural diagram of the cyclonic mass transfer component in the present invention;

[0042] Figure 5 It is a schematic diagram of the principle of the cyclonic mass transfer component in the present invention;

[0043] Figure 6 It is a schematic diagram of the working state of the cyclonic mass transfer component in the present invention;

[0044] Figure 7 It is a schematic diagram of the Venturi structure in the present invention;

[0045] Figure 8 It is a schematic diagram of the liquid level of hydrogenation liquid phase products in the use state of the present invention;

[0046] Fig. 9 It is another structural schematic diagram of the non-thermal steam stripping enhanced hydrogenation liquid phase product dehydrogenation device in the present invention.

[0047] The following are the descriptions of the reference numerals:

[0048] 1. Hydrogen feed heating furnace; 2. Hydrogenation reactor; 3. Hot high fraction container; 4. Cold high fraction container; 5. Hot low fraction container; 6. Desulfurized hydrogen stripper for steam route; 7. Fractionation tower; 8. Desulfurized hydrogen stripper for hydrogen route; 8-1. Hydrogen inlet of stripper; 8-2. Pipeline A; 8-3. Liquid phase inlet of stripper; 8-4. Hydrogen outlet of stripper; 8-5. Pipeline B; 8-6. Liquid phase outlet of stripper; 8-7. Separation chamber of stripper unit; 8-8. Top partition of stripper unit; 8-9. Cyclone mass transfer component; 8-9-1. Cyclone mass transfer component outlet 8-9-2, gas inlet of swirl mass transfer component; 8-9-3, liquid inlet of swirl mass transfer component; 8-9-4, swirl cavity of swirl mass transfer component; 8-9-5, neck cavity of swirl mass transfer component; 8-10, mixing cavity of stripping unit; 8-11, middle partition of stripping unit; 8-12, negative pressure cavity of stripping unit; 8-13, Venturi; 8-13-1, Venturi outlet; 8-13-2, gradually expanding section; 8-13-3, gradually contracting section; 8-13-4, liquid inlet of Venturi; 8-13-5, gas inlet of Venturi; 9, degassing cyclone. DETAILED DESCRIPTION

[0049] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0050] In the description of the present invention, it is necessary to understand that the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0051] For example, the inner cavity of the stripping tower has three stripping units, and from bottom to top, they are the first stripping unit, the second stripping unit and the third stripping unit;

[0052] Embodiment 1, as Figure 1-9 As shown, a method for removing hydrogen sulfide from a liquid phase product of non-thermal stripping enhanced hydrogenation comprises the following specific steps:

[0053] Step 1: injecting the hydrogenated liquid phase product from the low fraction container into the bottom of the desulfurization hydrogen stripping tower of the hydrogen route;

[0054] Step 2: using hydrogen as the stripping medium, injecting hydrogen into the negative pressure chamber of the third stripping unit in the desulfurization hydrogen stripping tower of the hydrogen route, so that the hydrogen and the hydrogenation liquid phase product flow upward through the corresponding venturi in parallel to the mixing chamber of the third stripping unit;

[0055] Step 3: The hydrogenated liquid phase product entering the mixing chamber of the third stripping unit is separated from the hydrogen. The separated hydrogenated liquid phase product and hydrogen pass through the corresponding cyclone mass transfer component so that the hydrogen and the hydrogenated liquid phase product are in a cyclone flow state in the inner cavity of the cyclone mass transfer component and flow upward to the separation chamber of the third stripping unit;

[0056] Step 4: The hydrogenated liquid phase product entering the separation chamber of the third stripping unit is separated from the hydrogen, and the separated hydrogen enters the negative pressure chamber of the second stripping unit through a pipeline. According to the principles of the above steps 2 and 3, the hydrogenated liquid phase product in the second stripping unit enters the third stripping unit, and then the hydrogen in the separation chamber of the second stripping unit enters the negative pressure chamber of the first stripping unit, and the hydrogenated liquid phase product in the first stripping unit enters the second stripping unit; finally, the hydrogen is discharged from the separation chamber of the first stripping unit to the outside of the stripping tower, and the hydrogenated liquid phase product flows out from the top outlet of the stripping tower and enters the downstream;

[0057] Specifically, the flow direction of the hydrogenated liquid phase product is sequentially through the bottom of the inner cavity of the stripping tower, through the venturi, into the mixing cavity of the first stripping unit, the separation cavity of the first stripping unit, through the venturi again, into the mixing cavity of the second stripping unit, the separation cavity of the second stripping unit, through the venturi again, into the mixing cavity of the third stripping unit, the separation cavity of the third stripping unit, and then discharged from the inner cavity of the stripping tower, and as a whole, flows from bottom to top in the inner cavity of the stripping tower;

[0058] In order to realize the recycling of hydrogen and reduce the consumption of hydrogen, the hydrogen discharged from the stripping tower from the separation chamber of the first stripping unit enters the pressure swing adsorption device for regeneration, and the regenerated hydrogen is injected into the negative pressure chamber of the third stripping unit in the stripping tower again to realize the recycling of hydrogen; wherein, the pressure swing adsorption device adopts the existing device, and its specific structure is not repeated;

[0059] In the above scheme, when the hydrogenated liquid phase product contacts the hydrogen, the hydrogen sulfide in the hydrogenated liquid phase product is transferred to the hydrogen, and the hydrogenated liquid phase product flows out from the top outlet of the stripping tower and enters the downstream;

[0060] In this process, from a macroscopic point of view, the hydrogenation liquid phase product flows from bottom to top in the inner cavity of the stripper, and the hydrogen flows from top to bottom in the inner cavity of the stripper, and the two are in countercurrent contact;

[0061] To ensure that the hydrogen liquid phase product flows smoothly from bottom to top, the liquid level of the hydrogenated liquid phase product in the mixing chamber of the stripping unit is located between the liquid inlet and the gas inlet of the cyclone mass transfer component, and the liquid level of the hydrogenated liquid phase product in the separation chamber of the stripping unit is higher than the Venturi liquid inlet.

[0062] According to needs, the volume flow ratio of hydrogen to hydrogenated liquid phase product is 0.25-5; the hydrogen pressure in the negative pressure cavity of the first stripping unit is less than the hydrogen pressure in the separation cavity of the third stripping unit, and the pressure difference is 1-5 kPa; the hydrogen Reynolds number in the pipeline is not greater than 300; the density of the hydrogenated liquid phase product is 600-890 kg / m3, and the viscosity of the hydrogenated liquid phase product is 0.01-0.5 cP; the Venturi throat flow rate is 5-20 m / s; the liquid Reynolds number of the cyclone mass transfer component is 3000-10000; the velocity at the liquid inlet of the cyclone mass transfer component is 1-5.5 m / s, and the velocity at the hydrogen inlet of the cyclone mass transfer component is 2-10 m / s.

[0063] In this embodiment, the ratio of the volume flow rate of hydrogen to the hydrogenated liquid phase product is 3.5; the density of the hydrogenated liquid phase product is 820 kg / m3, and the viscosity of the hydrogenated liquid phase product is 0.2 cP; the velocity at the liquid inlet of the swirl mass transfer component is 2 m / s, the velocity at the hydrogen inlet of the swirl mass transfer component is 7 m / s, and the Reynolds number of the hydrogenated liquid phase product of the swirl mass transfer component is 5000; the Venturi throat flow rate is 10 m / s;

[0064] In one embodiment, a non-thermal stripping enhanced hydrogenation liquid product desulfurization device is also provided, such as Figure 3 As shown, the device includes a hydrogen desulfurization stripping tower 8 for a hydrogen route, wherein the bottom of the hydrogen desulfurization stripping tower 8 for a hydrogen route is provided with a stripping tower liquid phase inlet 8-3, and the top is provided with a stripping tower liquid phase outlet 8-6;

[0065] like Figure 3 As shown, the inner cavity of the dehydrogen sulfide stripping tower 8 of the hydrogen route has three stripping units connected in series, and from bottom to top they are the first stripping unit, the second stripping unit and the third stripping unit; each stripping unit includes a stripping unit negative pressure cavity 8-12, a stripping unit mixing cavity 8-10, and a stripping unit separation cavity 8-7 which are arranged from bottom to top, the dehydrogen sulfide stripping tower 8 of the hydrogen route is provided with a stripping tower hydrogen inlet 8-1 for supplying hydrogen to the uppermost stripping unit negative pressure cavity 8-12, and the dehydrogen sulfide stripping tower 8 of the hydrogen route is provided with a stripping tower hydrogen outlet 8-4 for discharging hydrogen in the lowermost stripping unit separation cavity 8-7;

[0066] like Figure 3 As shown, each stripping unit further includes a stripping unit middle baffle 8-11 for isolating the stripping unit negative pressure chamber 8-12 and the stripping unit mixing chamber 8-10 and a stripping unit top baffle 8-8 for isolating the stripping unit mixing chamber 8-10 and the stripping unit separation chamber 8-7, and a plurality of swirling mass transfer components 8-9 rotatably connected to the stripping unit top baffle 8-8 are evenly arranged on the lower plate surface;

[0067] Specifically, the separation chamber of the third stripping unit is connected to the negative pressure chamber of the second stripping unit through pipeline B8-5, and the separation chamber of the second stripping unit is connected to the negative pressure chamber of the first stripping unit through pipeline A8-2;

[0068] In this implementation, if Figure 3 As shown, pipeline A8-2 and pipeline B8-5 are arranged outside the dehydrogen sulfide stripping tower of the hydrogen route. If necessary, pipeline A8-2 and pipeline B8-5 can also be arranged in the inner cavity of the dehydrogen sulfide stripping tower of the hydrogen route.

[0069] like Figure 4-6 As shown, the swirl mass flow component 8-9 has a swirl mass flow component swirl chamber 8-9-4 inside, and a swirl mass flow component necking chamber 8-9-5 is provided at the upper end of the swirl mass flow component swirl chamber 8-9-4. Specifically, the swirl mass flow component necking chamber 8-9-5 is located in the middle of the swirl mass flow component swirl chamber 8-9-4, and the swirl mass flow component necking chamber 8-9-5 is a cylindrical structure; that is, the swirl mass flow component necking chamber 8-9-5 and the swirl mass flow component swirl chamber 8-9-4 are coaxially arranged;

[0070] like Figure 3-4 As shown, the top of the swirl mass transfer component neck cavity 8-9-5 is provided with a swirl mass transfer component outlet 8-9-1 extending to the upper plate of the stripping unit top baffle 8-8, and the swirl mass transfer component 8-9 is evenly provided with a swirl mass transfer component gas inlet 8-9-2 for hydrogen to enter the swirl mass transfer component swirl cavity 8-9-4, and the swirl mass transfer component 8-9 is also evenly provided with a swirl mass transfer component liquid inlet 8-9-3 for hydrogenation liquid phase products to enter the swirl mass transfer component swirl cavity 8-9-4, and the swirl mass transfer component liquid inlet 8-9-3 is spaced below the swirl mass transfer component gas inlet 8-9-2;

[0071] As needed, the swirl mass transfer component 8-9 is cylindrical and has a necking portion at the top. There is a cylindrical swirl mass transfer component swirl chamber 8-9-4 inside the swirl mass transfer component 8-9, and the wall thickness of the swirl mass transfer component 8-9 is uniform; the necking portion movably penetrates the top partition plate 8-8 of the stripping unit, and is fixedly or rotatably connected to the top partition plate 8-8 of the stripping unit, and the upper end of the necking portion is open, that is, the gas phase and liquid phase of the swirl chamber 8-9-4 of the swirl mass transfer component are discharged into the separation chamber 8-7 of the stripping unit through the swirl mass transfer component outlet 8-9-1.

[0072] Specifically, Figure 5-6 As shown, the swirl mass transfer component gas inlet 8-9-2 and the swirl mass transfer component liquid inlet 8-9-3 are both tangentially arranged, and the swirl mass transfer component gas inlet 8-9-2 and the swirl mass transfer component liquid inlet 8-9-3 are in the same direction;

[0073] The working principle of the swirl mass transfer component 8-9 is as follows: both gas and liquid are injected from the tangential inlet of the corresponding swirl mass transfer component 8-9 side wall to form a gas-liquid swirl flow. Since the liquid must move to the central swirl mass transfer component neck cavity 8-9-5, the liquid is a continuous phase. The gas is performing swirl motion while penetrating the liquid continuous phase. Under the swirl centrifugal acceleration condition, the relative slip speed of gas and liquid is accelerated. According to the surface renewal mass transfer theory, gas-liquid equilibrium can be achieved in a very short time, reflecting the characteristics of enhanced mass transfer.

[0074] like Figure 2 and 7 As shown, the upper end of the venturi 8-13 has a venturi outlet 8-13-1 extending to the upper plate surface of the partition 8-11 in the stripping unit, the lower end of the venturi 8-13 is provided with a venturi liquid inlet 8-13-4, and one side of the venturi 8-13 is provided with a venturi gas inlet 8-13-5. The venturi 8-13 is provided with a gradually expanding section 8-13-2 at the upper side of the venturi gas inlet 8-13-5, and the venturi 8-13 is provided with a gradually contracting section 8-13-3 at the lower side of the venturi gas inlet 8-13-5, and the upper end of the gradually contracting section 8-13-3 is sealed and abutted with the lower end of the gradually expanding section 8-13-2.

[0075] like Figure 2 and 7 As shown, according to the needs, the tapering angle β of the tapering section is 2 to 6°, and the tapering angle γ of the gradually expanding section is 5 to 16°. In this embodiment, the tapering angle β of the tapering section is 5°, and the tapering angle γ of the gradually expanding section is 10°;

[0076] The swirl diameter of the swirl mass transfer component 8-9 is 20-200 mm. In this embodiment, the swirl diameter of the swirl mass transfer component is 25 mm. The swirl diameter of the swirl mass transfer component 8-9 is also the diameter of the swirl cavity 8-9-4 of the swirl mass transfer component.

[0077] In another embodiment, if Fig. 9 As shown, in order to further reduce the height and manufacturing cost of the desulfurization hydrogen stripping tower 8 of the hydrogen route, the second stripping unit negative pressure cavity and the first stripping unit separation cavity share a cavity, and the stripping unit venturi gas inlet 8-13-5 in the second stripping unit negative pressure cavity is directly connected to one end of the corresponding pipeline; the third stripping unit negative pressure cavity and the second stripping unit separation cavity share a cavity, and the stripping unit venturi gas inlet 8-13-5 in the third stripping unit negative pressure cavity is directly connected to the hydrogen source.

[0078] According to research, in order to ensure better operation of the swirl mass transfer components 8-9, when the velocity at the liquid inlet of the swirl mass transfer component is 1-2.5 m / s, the swirl diameter of the swirl mass transfer component is 20-60 mm; when the velocity at the liquid inlet of the swirl mass transfer component is 2.5-4 m / s, the swirl diameter of the swirl mass transfer component is 60-100 mm; when the velocity at the liquid inlet of the swirl mass transfer component is 4-5.5 m / s, the swirl diameter of the swirl mass transfer component is 100-200 mm.

[0079] Specifically, the hydrogen sulfide content in the treated hydrogenation liquid phase product is stably less than 1 ppm, so that the diesel copper sheet corrosion is at the 1a or 1b level, meeting the product quality requirements.

[0080] In this embodiment, the hydrogen sulfide stripping technology using the hydrogen route increases the cost of hydrogen recycling and regeneration, but eliminates the steam consumption, acidic water treatment, top cooling water consumption, power consumption of moving equipment, etc. of the steam stripping technology. Taking all factors into consideration, the hydrogen sulfide separation cost is reduced by 30% by using the hydrogen stripping route with enhanced mass transfer.

[0081] Embodiment 2 is different from Embodiment 1 in that the swirl diameter of the swirl mass transfer component is 80 mm; the ratio of the volume flow rate of hydrogen to the hydrogenated liquid phase product is 2; the density of the hydrogenated liquid phase product is 700 kg / m3, and the viscosity of the hydrogenated liquid phase product is 0.1 cP; the velocity at the liquid inlet of the swirl mass transfer component is 3 m / s, the velocity at the hydrogen inlet of the swirl mass transfer component is 10 m / s, and the Reynolds number of the hydrogenated liquid phase product of the swirl mass transfer component is 4000; the Venturi throat flow rate is 16 m / s.

[0082] Example 3: An experiment was conducted under the apparatus of Example 1. When the volume flow ratio of hydrogen to hydrogenated liquid phase product increased to 7, the hydrogen sulfide content of the hydrogenated liquid phase product increased sharply to tens of ppm, and the diesel copper sheet corrosion was at level 3a or 3b.

[0083] After analysis, it was found that the reason was that when the gas-liquid ratio was too large, hydrogen countercurrent circulation could not be formed, and the stripping mass transfer only occurred in the third stripping unit, resulting in a cliff-like drop in the hydrogen sulfide separation efficiency.

[0084] Comparative Cases

[0085] In a domestic diesel hydrogenation unit, the stripper feed comes from the hot low-pressure separator and the cold low-pressure separator, and the stripper top pressure is 0.8MPa. The liquid phase injection rate of the stripper is 220t / h. When the steam consumption is greater than 3t / h, the hydrogen sulfide content of the liquid phase hydrogenation product is less than 1ppm.

[0086] The above shows and describes the basic principles, main features and advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A method for dehydrogenating liquid products by non-thermal stripping enhanced hydrogenation, characterized in that: It includes the following steps: Step 1: Inject the hydrogenated liquid-phase product from the low-pressure container into the bottom of the stripping column; Step 2: Use hydrogen as the stripping medium and inject hydrogen into the negative-pressure cavity of the stripping unit in the stripping column. The hydrogen in the negative-pressure cavity of the stripping unit attracts the hydrogenated liquid-phase product through a Venturi, causing the hydrogenated liquid-phase product and hydrogen to flow upward in parallel to the mixing cavity of the stripping unit; Step 3: The hydrogenated liquid-phase product entering the mixing cavity of the stripping unit is separated from hydrogen. After separation, the hydrogenated liquid-phase product and hydrogen enter the swirling mass-transfer component at the top of the mixing cavity of the stripping unit and flow in a swirling manner, and then enter the separation cavity of the stripping unit above the mixing cavity of the stripping unit; Among them, the hydrogenated liquid-phase product and hydrogen present a completely mixed flow state in the swirling cavity of the swirling mass-transfer component; Step 4: The hydrogenated liquid-phase product entering the separation cavity of the stripping unit is separated from hydrogen. The separated hydrogen is discharged from the stripping column outward from the separation cavity of the stripping unit, and the separated hydrogenated liquid-phase product enters the upper stripping unit through a Venturi in the upper stripping unit and repeats Steps 2, 3, and 4 above, and finally flows out from the top outlet of the stripping column and enters the downstream; Among them, the volume flow ratio of hydrogen to the hydrogenated liquid-phase product is 0.25 - 5; the liquid level of the hydrogenated liquid-phase product in the mixing cavity of the stripping unit is between the liquid inlet and gas inlet of the swirling mass-transfer component, and the liquid level of the hydrogenated liquid-phase product in the separation cavity of the stripping unit is higher than the liquid inlet of the Venturi in the upper stripping unit; Among them, N stripping units are provided in the inner cavity of the stripping column along its height direction. The N stripping units are successively the first stripping unit, the second stripping unit,..., the Nth stripping unit from bottom to top, where N≥2.

2. The method for desulfurizing hydrogen from a liquid phase product by non-thermal stripping enhanced hydrogenation according to claim 1, characterized in that: In Step 2, hydrogen is injected into the negative-pressure cavity of the Nth stripping unit in the stripping column and finally discharged from the separation cavity of the first stripping unit outward from the stripping column, and the hydrogen discharged from the separation cavity of the Mth stripping unit enters the negative-pressure cavity of the (M - 1)th stripping unit through a pipeline, where 1<M≤N; macroscopically, hydrogen and the hydrogenated liquid-phase product present countercurrent contact.

3. The method for desulfurizing hydrogen from liquid phase products by non-thermal stripping enhanced hydrogenation according to claim 2, characterized in that: The hydrogen pressure in the negative-pressure cavity of the first stripping unit is less than the hydrogen pressure in the separation cavity of the Nth stripping unit, and the pressure difference is 1 - 5 kPa; the Reynolds number of hydrogen in the pipeline is not greater than 300.

4. The method for desulfurizing hydrogen from a liquid phase product by non-thermal stripping enhanced hydrogenation according to claim 1, characterized in that: The swirling mass-transfer component internally has a swirling cavity of the swirling mass-transfer component. The upper end of the swirling cavity of the swirling mass-transfer component is provided with a necking cavity of the swirling mass-transfer component, and the upper end of the necking cavity of the swirling mass-transfer component is provided with an outlet of the swirling mass-transfer component communicating with the separation cavity of the stripping unit. The periphery of the swirling mass-transfer component is evenly and annularly provided with gas inlets of the swirling mass-transfer component for hydrogen to enter the swirling cavity of the swirling mass-transfer component. The periphery of the swirling mass-transfer component of the stripping unit is also evenly and annularly provided with liquid inlets of the swirling mass-transfer component for the hydrogenated liquid-phase product to enter the swirling cavity of the swirling mass-transfer component, and the liquid inlet of the swirling mass-transfer component is located below the gas inlet of the swirling mass-transfer component.

5. The method for desulfurizing hydrogen from liquid phase products by non-thermal stripping enhanced hydrogenation according to claim 1, characterized in that: The density of the hydrogenated liquid-phase product is 600 - 890 kg / m3, and the viscosity of the hydrogenated liquid-phase product is 0.01 - 0.5 cP.

6. The method for desulfurizing hydrogen from liquid phase products by non-thermal stripping enhanced hydrogenation according to claim 1, characterized in that: The Venturi has a tapering section with a tapering angle of 2-6° at the lower side corresponding to the hydrogen inlet, and a gradually expanding section with a tapering angle of 5-16° at the upper side corresponding to the hydrogen inlet, and the small end of the tapering section is sealed and abutted with the small end of the gradually expanding section.

7. The method for desulfurizing hydrogen from liquid phase products by non-thermal stripping enhanced hydrogenation according to claim 6, characterized in that: The flow velocity of the Venturi throat is 5-20 m / s.

8. The method for desulfurizing hydrogen from liquid phase products by non-thermal stripping enhanced hydrogenation according to claim 1, characterized in that: The Reynolds number of the hydrogenated liquid phase product of the cyclonic mass transfer component is 3000-10000.

9. The method for desulfurizing hydrogen from liquid phase products by non-thermal stripping enhanced hydrogenation according to claim 1, characterized in that: The velocity at the liquid inlet of the cyclonic mass transfer component is 1-5.5 m / s, and the velocity at the hydrogen inlet of the cyclonic mass transfer component is 2-10 m / s.

10. The method for desulfurizing hydrogen from liquid phase products by non-thermal stripping enhanced hydrogenation according to claim 1, characterized in that: The swirl diameter of the swirl mass transfer component is 20-200 mm; Among them, when the velocity at the liquid inlet of the swirl mass transfer component is 1~2.5 m / s, the swirl diameter of the swirl mass transfer component is 20~60 mm; when the velocity at the liquid inlet of the swirl mass transfer component is 2.5~4 m / s, the swirl diameter of the swirl mass transfer component is 60~100 mm; when the velocity at the liquid inlet of the swirl mass transfer component is 4~5.5 m / s, the swirl diameter of the swirl mass transfer component is 100~200 mm.

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