CN204656510U - A kind of alkylation reactor - Google Patents

Abstract

The utility model discloses an alkylation reactor. The alkylation reactor includes a liquid distributor, a liquid riser, an olefin distribution pipe, a gas outlet pipe, and a liquid outlet pipe. The liquid distributor is located at the bottom of the reactor and is composed of a main pipe, a feed pipe and an outlet nozzle. The bottom of the liquid distributor is provided with a feed pipe, and the top is provided with an outlet nozzle. The liquid distributor communicates with the liquid rising pipe through the outlet nozzle, and the liquid in the upper part rises The tube has a built-in olefin distribution tube and packing, and a gas outlet tube and a liquid outlet tube are arranged on the top. Alkanes and liquid acid catalysts are evenly mixed in the liquid distributor and then sprayed into the liquid riser, contacting and reacting with olefins sprayed from the olefin distribution pipe, and the reaction is removed by the self-evaporation of _C4 alkanes during the alkylation reaction The hot, reacted alkylate and liquid acid mixture exits through the liquid outlet tube and the gas exits through the gas outlet tube at the top of the liquid riser. The utility model can fully mix the liquid acid and hydrocarbon raw materials, reduce the polymerization between olefins, and has the characteristics of good reaction effect, large operation flexibility, and investment saving.

Description

an alkylation reactor

technical field

The utility model belongs to the field of petrochemical industry and relates to an alkylation reactor, in particular to a sulfuric acid catalyzed _C4 alkylation reactor and a reaction method.

Background technique

In the field of petroleum refining, sulfuric acid alkylation is a process in which isoparaffins react with olefins to generate alkylated products in the presence of concentrated sulfuric acid catalyst. The factors affecting the sulfuric acid alkylation reaction are extremely complicated. It is generally believed that the controlling step of the sulfuric acid alkylation reaction rate is the mass transfer rate of isobutane to the sulfuric acid phase. Theoretical and practical studies have shown that whether sulfuric acid alkylation can proceed smoothly depends on whether the dispersion, contact and circulation of acid hydrocarbons are good, and whether the heat of reaction can be removed in a timely and efficient manner. Therefore, the sulfuric acid alkylation reaction must not only realize the full mixing of the two phases of the acid hydrocarbon, but also ensure that the alkylation reaction is carried out at a lower temperature.

U.S. Patent No. 3,759,318 discloses a horizontal reactor used in the sulfuric acid alkylation process. The main structure is a horizontal pressure vessel, which is equipped with circulation pipes, heat exchange tube bundles and spiral stirring blades. The reaction raw material enters the suction side of the helical stirring blade of the reactor. Under the strong agitation of the impeller, the reaction material diffuses rapidly and forms an emulsion with the acid. The emulsion circulates continuously in the reactor and reacts. The heat of the alkylation reaction passes through The heat exchange tube bundle is removed, and part of the emulsion enters the settler through the riser for separation of acids and hydrocarbons. This patent reactor is similar to patent US 3759318.

U.S. Patent No. 6,194,625 B1 discloses a segmented feed alkylation reactor, the reaction zone is divided into a plurality of series-connected sections, fresh raw materials are divided into multiple strands and introduced into each reaction section, and the recycled sulfuric acid It is a serial flow type, and mechanical stirring is used for mixing in each reaction zone. Although this structure overcomes the problem of large backmixing, the structure is too complicated. In addition, this kind of stirring paddle driven by a fixed-speed motor is prone to leakage due to poor sealing under medium and high pressure operating conditions.

Chinese patent CN 101679143 A discloses a system and process for alkylation, including a high-shear disperser, using the high-shear disperser to form sulfuric acid and hydrocarbons into the continuous phase, and the hydrocarbon as the dispersed phase The mixed emulsion is introduced into the alkylation reactor under appropriate alkylation conditions, and the alkylation reaction is completed under the strong stirring of the impeller. Since this patent uses a high-speed shear disperser to emulsify the reactant alkane and catalyst sulfuric acid separately, the dispersion and reaction need to be carried out separately. At the same time, the power of the high-shear disperser is relatively high, and the energy consumption is relatively high.

Chinese patent CN 101104570 A discloses a kind of alkylation reactor, and the reactor is a static mixing reactor. The static mixer is filled with wire mesh and contact structure packing with a porosity greater than 50%. The hydrocarbon mixture composed of olefins and isobutane enters the reactor, contacts with sulfuric acid catalyst, and undergoes emulsification reaction. The reaction materials rely on the pressure drop of the packing itself to vaporize the light hydrocarbon components to absorb the heat of reaction. The reaction heat removal method of the patented reactor is light hydrocarbon gasification. In order to maintain a low reaction temperature, the reactor needs a large amount of gasification space. In addition, static mixers also have disadvantages such as excessive pressure drop.

U.S. Patent No. 5,443,799 discloses an alkylation reactor, which is divided into a premixing zone and a reaction zone. In the pre-mixing zone, isobutane is sprayed out from the nozzle and mixed with sulfuric acid to form an emulsion. In the reaction zone, the injected olefins contact and react with the emulsion from the premixing zone. The volume of the reaction zone of the reactor is larger than that of the premixing zone. After the mixture from the premixing zone enters the reaction zone, due to the sudden increase in the volume of the reaction zone, the light components in the mixture are vaporized, and the adiabatic expansion absorbs the alkylation reaction. The heat released. The reaction temperature of this technology is 8～20 ℃, and the reaction temperature is on the high side.

Utility model content

The utility model discloses an alkylation reactor, which can break the reaction liquid with relatively low viscosity into small liquid droplets and disperse them in the high-viscosity acid phase liquid, so that it can be separated from the high-viscosity acid phase in a very short time. Uniform mixing and emulsification within a short period of time, providing a large liquid-liquid contact area and achieving a high conversion rate. The reactor has the characteristics of simple structure, large liquid-liquid contact area, convenient operation and high production efficiency.

The utility model provides an alkylation reactor, which includes a liquid distributor, a liquid riser and an olefin distribution pipe, and is characterized in that the liquid riser consists of an upper cylindrical head, a middle cylindrical body and a lower inverted round table The gas outlet pipe is arranged on the top of the cylindrical head, the liquid outlet pipe is arranged on the side of the upper part of the cylindrical head, the olefin distribution pipe and packing are arranged in the middle cylindrical cylinder, and the liquid distributor is located at the bottom of the liquid riser. The liquid distributor is composed of an alkane feed pipe, a liquid acid feed pipe, a main pipe and an outlet nozzle. The alkane feed pipe is inserted into the main pipe from the bottom of the liquid distributor, and its axis coincides with the axis of the main pipe. A mixing chamber is formed between the alkane feed pipes, and the liquid acid feed pipe enters the mixing chamber tangentially from the main pipe.

The further technical feature of the utility model is that: the end of the alkane feed pipe is tapered, and the distance _h1 from the apex of the cone to the top of the main pipe is ₂ to 5 times the outer diameter d1 of the alkane feed pipe.

The further technical feature of the utility model is that: there are two liquid distributors, the outer diameter of the main pipe on the liquid distributor is d, the outer diameter of the cylindrical body in the liquid riser is D, and D is 3 of d. ~6 times.

The further technical feature of the utility model is that: small holes with a diameter of 1 to 5 mm are arranged on the alkane feed pipe within 360°, and the opening rate is 15% to 50% (based on the outer surface of the alkane feed pipe) .

The further technical feature of the utility model is that: the packing adopts a single stage, two stages or multiple stages, preferably a multistage packing, the number of stages is 2 to 5, and the height of each stage of packing is 0.05 to 0.2 times the height H of the liquid riser.

The further technical feature of the utility model is that: the olefin distribution pipe adopts a tree-like branch structure, and small holes with a diameter of 1 to 10 mm are arranged on the branch pipe within a range of 360°, and the opening rate is 10% to 50% (based on olefin Distributing pipe outer surface as a reference), preferably 20% to 40%.

The utility model is suitable for the alkylation reaction, especially for the alkylation reaction with high viscosity sulfuric acid as the catalyst.

Below in conjunction with accompanying drawing and specific embodiment, the utility model is described in further detail.

Description of drawings:

Fig. 1 is a kind of alkylation reactor structural diagram of the utility model;

Fig. 2 is A-A sectional view among Fig. 1;

Fig. 3 is the B-B sectional view among Fig. 1;

Fig. 4 is the C-C sectional view among Fig. 1;

Fig. 5 is a process flow diagram of the application of an alkylation reactor of the present invention in the alkylation reaction.

Reference signs shown in the figure:

1-alkylation reactor; 2-liquid distributor; 3-liquid riser; 4-alkene distribution pipe; 5-gas outlet pipe; 6-liquid outlet pipe; 7-packing; 8-alkane feed pipe; 9 -liquid acid feed pipe; 10-main pipe; 11-outlet nozzle; 12-settler; 13-liquid acid pump; 14-flash tank; 15-compressor; 16-deisobutanizer; 17-inversion Round table-shaped cylinder; 18-cylindrical cylinder; 19-cylindrical head.

Detailed ways

As shown in Figure 1, an alkylation reactor 1 comprises a liquid distributor 2, a liquid riser 3 and an olefin distribution pipe 4, the liquid riser 3 consists of an upper cylindrical head 19, a middle cylindrical shell 18 It is composed of an inverted conical cylinder 17 at the lower part, a gas outlet pipe 5 is arranged on the top of the cylindrical head 19, a liquid outlet pipe 6 is arranged on the side of the upper part of the cylindrical head 19, and the liquid distributor 2 is located at the bottom of the liquid riser 3. The liquid distributor 2 is composed of an alkane feed pipe 8 , a liquid acid feed pipe 9 , a main pipe 10 and an outlet nozzle 11 . The alkane feed pipe 8 is inserted into the main pipe 10 from the bottom of the liquid distributor 2, its axis coincides with the axis of the main pipe 10, and its outer diameter is d ₁ . A small hole of 5 mm, with an opening rate of 15% to 50% (based on the outer surface of the alkane feed pipe 8), the end of the alkane feed pipe 8 is tapered, and the distance h1 from the apex of the cone to the top _of the main pipe ₁₀ is d1 2 to 5 times of that; a mixing chamber is formed between the main pipe 10 and the alkane feed pipe 8, the liquid acid feed pipe 9 enters the mixing chamber tangentially from the main pipe 10 (as shown in Figure 4), and the number of liquid distributors 2 is 2 1 and 3, where d is the outer diameter of the main pipe 10 on the liquid distributor 2, and D is the outer diameter of the cylindrical body 18 in the liquid riser 3. The liquid riser 3 is provided with an olefin distribution pipe 4 and a filler 7 . The outer diameter D of the cylindrical body 18 is 3 to 6 times the outer diameter d of the liquid distributor 2, and the height H of the liquid riser 3 should ensure that the residence time of the liquid in the riser 3 is 1 to 10 minutes. Packing 7 is housed in the liquid riser 3, adopts single section, two sections or multiple sections, preferably multi-section packing, the number of sections is 2～5 sections, (the packing 7 shown in Fig. 1 is 2 sections.) The height of each section of packing is the liquid riser 3. The height H is 0.05 to 0.2 times. There is an interval space between each section of packing, and the olefin distribution pipe 4 is arranged in the space. The olefin distribution pipe 4 adopts a tree-like branch structure (as shown in Figure 2). Small holes with a diameter of 1-10 mm are arranged within a range of 360°, and the opening ratio is 10%-50% (based on the outer surface of the olefin distribution pipe 4), preferably 20%-40%.

As shown in Figure 5, a process flow chart of the application of an alkylation reactor in the alkylation reaction of the present invention, according to the process flow chart, the alkylation reaction process is: alkane, light olefin and liquid The acid catalyst is fed into the reactor, and the light olefins include butene, propylene, pentene or olefin mixture, and the preferred reaction materials are isobutane, liquefied gas after ether and concentrated sulfuric acid. Under the condition of operating pressure of 0.4~0.6MPa and reaction temperature of 0~10℃, the alkylation reaction of alkenes and alkanes can be realized; the ratio of alkanes to alkanes of the reaction materials is 8:1~15:1, and the ratio of acid to hydrocarbon is 1. :1～2:1.

Other process steps involved in the method described in the utility model, such as raw material pretreatment, gas-liquid separation, reaction effluent pickling, alkali washing and other processing units are the same as the conventional alkylation process. The method provided by the present invention will be further described below in conjunction with FIG. 5 .

Isobutane and liquid acid catalyst are sprayed into the main pipe 10 from the alkane feed pipe 8 and the liquid acid feed pipe 9 respectively, and the two materials are collided, emulsified and mixed in the main pipe 10 to form a liquid in the liquid distributor 2 Acidic hydrocarbon emulsion with acid as the continuous phase and alkanes as the dispersed phase. The mixed acidic hydrocarbon emulsion is sprayed into the liquid riser 3 through the outlet nozzle 11 at high speed, and the material flows upward after entering the liquid riser 3. The olefins ejected from the olefin distribution pipe 4 in the pipe 3 are quickly contacted and mixed, and the emulsion containing olefins, alkanes and liquid acids flows upwards into the packing area 7, and is fully mixed under the cutting and dispersing action of the packing 7. A hydrocarbon mixture of alkanes and alkenes is contacted with a liquid acid catalyst under conditions to obtain an alkylate. The heat generated in the alkylation process vaporizes the _C4 alkanes, and the heat of reaction is taken away by the heat of vaporization required for its evaporation, and then the gas enters the compressor 15 through the gas outlet pipe 5 at the top of the liquid riser 3, and reacts The final alkylated oil and liquid acid mixture enters the acid hydrocarbon settler 12 through the liquid outlet pipe 6 for static separation, and the acid phase separated in the lower layer is pumped into the liquid acid feed pipe 9 of the liquid distributor 2 as circulating acid by the liquid acid pump 13 , a small amount is directly discharged from the device in the form of waste acid. The mixed hydrocarbon phase of the upper layer enters the flash tank 14, the gas phase in the flash tank 14 enters the follow-up unit after being compressed by the compressor 15, the liquid phase in the flash tank 14 enters the deisobutanizer 16, and the isobutanizer separated from the top of the tower The butane and the recycled isobutane from the compressor 20 are returned to the mixed hydrocarbon buffer tank 25, and the alkylate product is fractionated from the bottom of the tower to enter the subsequent processing unit.

Claims (7)

1. An alkylation reactor, comprising a liquid distributor (2), a liquid riser (3) and an olefin distribution pipe (4), is characterized in that: the liquid riser (3) consists of an upper cylindrical head (19 ), the middle cylindrical shell (18) and the lower inverted conical shell (17), the top of the cylindrical head (19) is provided with a gas outlet pipe (5), and the upper side of the cylindrical head (19) The liquid outlet pipe (6) is arranged, the olefin distribution pipe (4) and the filler (7) are arranged in the middle cylindrical shell (18), the liquid distributor (2) is positioned at the bottom of the liquid riser pipe (3), and the liquid distribution The device (2) is composed of an alkane feed pipe (8), a liquid acid feed pipe (9), a main pipe (10) and an outlet nozzle (11), and the alkane feed pipe (8) is fed from the liquid distributor (2 ) is inserted into the main body pipe (10), its axis coincides with the axis of the main body pipe (10), and a mixing chamber is formed between the main body pipe (10) and the alkane feed pipe (8), and the liquid acid feed pipe (9) flows from the main body The tube (10) enters the mixing chamber tangentially. 2. A kind of alkylation reactor according to claim 1, characterized in that: the end of the alkane feed pipe (8) is tapered, and the distance _h1 from the apex of the cone to the top of the main pipe (10) is the alkane feed pipe (8). ₂ ～5 times of the outer diameter d1 of feed pipe (8). 3. An alkylation reactor according to claim 1, characterized in that: there are two liquid distributors (2), and the outer diameter of the main pipe (10) on the liquid distributor (2) is d , The outer diameter of the cylindrical body (18) in the liquid riser (3) is D, and D is 3 to 6 times of d. 4. A kind of alkylation reactor according to claim 1, characterized in that: on the alkane feed pipe (8), small holes with a diameter of 1 to 5 mm are arranged within 360 °, and the opening ratio is 15%～50%, based on the outer surface of the alkane feed pipe (8). 5. A kind of alkylation reactor according to claim 1, characterized in that: the filler (7) adopts single stage, two stages or multiple stages, and the height of each stage of filler is the height H of the liquid riser (3). 0.05 to 0.2 times. 6. An alkylation reactor according to claim 1, characterized in that: the olefin distribution pipe (4) adopts a tree-like branch structure, and there are holes with a diameter of 1 to 10 mm arranged on the branch pipe within a range of 360°. The small holes have an opening ratio of 10% to 50%, based on the outer surface of the olefin distribution pipe (4). 7. An alkylation reactor according to claim 6, characterized in that: the opening ratio of the olefin distribution pipe (4) is 20%-40%.