CN107523328A - Using the alkylation of new micro passage reaction - Google Patents

Abstract

The invention discloses an alkylation method using a novel microchannel reactor, which uses isobutane and olefins as raw materials, uses liquid acid as a catalyst, and adds a considerable amount of propane as a refrigerant and entrainer to carry out alkylation Alkylation oil is obtained from the reaction; raw materials and catalysts enter the microchannel reaction zone in the microchannel reactor for alkylation reaction, and then enter the settling section for settling and stratification; after the reaction materials are settled and stratified, they enter the horizontal separation tank, pump out the catalyst in the lower layer, discharge the gas in the upper layer, and then send the product in the middle layer to the coalescence separator for separation. The microchannel reaction zone is composed of two parts: a tubular microchannel reaction zone and a surface microchannel reaction zone. The invention can be carried out at low temperature, the reaction raw materials do not need to be premixed, the bed pressure drop is small, the energy saving effect is good, the product quality is high, and the continuous production of high efficiency, energy saving, safety, low carbon and environmental protection can be realized.

Description

Alkylation method using a novel microchannel reactor

technical field

The invention belongs to the field of petrochemical industry and discloses an alkylation method using a novel microchannel reactor.

Background technique

At present, the requirements for gasoline indicators in various countries in the world are becoming more and more stringent. The production process of high-quality gasoline has become the focus of attention. The alkylation process is a conventional and mature method for producing high-quality gasoline blending components, that is, alkylated oil. method. Alkylation reaction is the reaction of isobutane and C3-C5 olefins under the action of acid catalyst to produce gasoline components with high octane number. The reaction product has the characteristics of low sulfur and does not contain aromatics or olefins.

Due to the microstructure of the filler in the internal reaction bed, the microchannel reactor has a very large specific surface area, which can reach hundreds or even thousands of times of the specific surface area of the stirred tank. Moreover, the microchannel reactor has excellent heat transfer and mass transfer capabilities, and the mass transfer efficiency is 10 to 100 times that of the kettle reactor, which can greatly improve the mixing efficiency of the reactants, and can realize the instant uniform mixing and mixing of materials. Efficient heat transfer, can quickly reach a steady state. Compared with traditional methods, reaction time and material consumption are reduced. Facilitates smooth control of strongly exothermic reactions.

CN 1953804 A discloses an alkylation method and system for staged addition of olefins in a microchannel. Take advantage of the excellent heat and mass transfer properties of microchannels to obtain higher temperature control. Relying on microchannel reaction technology to precisely control the temperature to minimize the oligomerization reaction, and the introduction of graded olefins reduces the local olefin concentration, increases the phase interface area of the acid hydrocarbon dispersion, and adjusts the temperature more accurately. Compared with the traditional process, it improves The octane number of the alkylated product improves the quality of the alkylated product.

However, in the above-mentioned patent, a large amount of paraffin material flow is fed, which will cause a bad initial distribution. The microchannel itself has a small radial diffusion coefficient. If the local temperature is too high, there will be a temperature difference in the reaction area, which will make the alkylation rate unbalanced. Moreover, filling the device with hydrogen increases the difficulty of separation and the risk of operation.

Therefore, how to upgrade the microchannel reactor and invent a new microchannel and alkylation process to overcome the above-mentioned defects is a technical problem to be solved by those skilled in the art.

Contents of the invention

Aiming at the deficiencies of the current alkylation technology, the invention discloses an alkylation method using a novel microchannel reactor, which makes the mixing of the reactant and the acid catalyst very uniform, reduces side reactions, and increases the yield of the reactant. The mass transfer efficiency with the catalyst improves the quality and yield of the reaction product, and at the same time achieves the purpose of saving energy. While reducing costs, it also reduces the impact on the environment and the instability of the performance of the products produced, replacing the traditional low-efficiency gap reactor production operations to achieve continuous energy-saving, safety, low-carbon and environmental protection chemical production.

In order to solve the above technical problems, the present invention is achieved in this way.

The alkylation method using a new microchannel reactor uses isobutane and olefins as raw materials and liquid acid as a catalyst to perform an alkylation reaction to obtain alkylated oil; the raw materials and catalysts enter the microchannel reactor After the alkylation reaction in the microchannel reaction zone, it enters the settling section for settling and stratification; the reaction material enters the horizontal separation tank after settling and stratifying, and the catalyst in the lower layer is extracted, and the gas in the upper layer is discharged, and the product in the middle layer is sent to the coalescence Separator for separation.

As a preferred solution, in the present invention, propane is added to the raw material as the refrigerant and entrainer of the raw material.

Further, the microchannel reactor of the present invention comprises a feed zone, a microchannel reaction zone, a settling zone and a separation zone; the outlet of the feed zone communicates with the inlet of the microchannel reaction zone; The outlet communicates with the inlet of the settling zone; the outlet of the settling zone communicates with the inlet of the separation zone.

Further, the microchannel reaction zone of the present invention is provided with at least one tubular microchannel reaction zone and one planar microchannel reaction zone.

Further, the tubular microchannel reaction zone and the planar microchannel reaction zone of the present invention are vertically and alternately arranged in series; the number of the tubular microchannel reaction zone is 2 to 10; the number of the planar microchannel reaction zone is 2 ~10.

Further, the ratio of space to volume occupied by the tubular microchannel reaction zone and the planar microchannel reaction zone of the present invention is 0.5-5:1.

Further, the tubular microchannel reaction zone of the present invention is composed of tubular microchannel components; the diameter of the channel is 0.1-10 mm; the surface microchannel reaction zone is composed of surface microchannel components; the channel gap between the two plates is 0.1-10 mm.

The inlet of the horizontal separation tank of the present invention can adopt a cyclone separation structure (of course, other structures can also be used), and a partition is arranged in the middle. The two phases of acid and hydrocarbon enter the suspension separator to realize the preliminary separation of acid and hydrocarbon. The acid phase is returned to the reactor through the circulation pump, and the hydrocarbon phase overflows to the other side of the partition, and is pumped into the coalescer for further separation.

Further, the reaction pressure of the alkylation reaction in the present invention is 0 MPa-1.0 MPa; the residence time of the reaction materials in the reactor is 1-200 min.

Further, the molar ratio of isobutane to olefins in the alkylation reaction of the present invention is 1-50:1; the volume ratio of acid hydrocarbons is 0.1-5:1; and the molar ratio of isobutane to propane is 1-100:1.

In the alkylation process of the invention, the acid catalyst separated by reaction can be recycled, which greatly reduces the loss of acid. During the reaction, the acid catalyst was supplemented at any time to ensure the concentration range. After the reaction, use nitrogen, inert gas or carbon dioxide to flush the device.

By using a suitable microchannel reactor in the alkylation process of the present invention, the pressure drop of the reactor bed is small, which is beneficial to mass transfer and heat transfer, makes the reaction more balanced, can realize efficient separation of reactants and products, and has less side reactions. The invention has the characteristics of mild operating conditions, easy control of the reaction, good distribution of raw materials, high product quality, etc., effectively avoids the problem of unbalanced reaction, mass transfer and heat transfer in the microchannel with a single structure, and at the same time solves the problem of large equipment size and low space utilization rate. It can realize continuous production with high efficiency, energy saving, safety, low carbon and environmental protection. The test results show that the alternate combination of tubular microchannel components and surface microchannel components (plate microchannel components) has a more efficient contact and mixing effect for the reaction materials in the immiscible alkylation reaction system, which is conducive to improving reaction efficiency and reducing side effects. The reaction occurs, effectively reducing the loss of catalyst.

The process of the present invention adopts the alkylation process of a microchannel reactor, and there is no need to provide additional power to pre-mix the catalyst and production raw materials, and the pressure drop of the bed layer is small, which is beneficial to the endothermic vaporization of alkanes, reduces the hot spots of the reaction, and solves the problem of reaction materials Difficult to separate problems caused by emulsification. A considerable amount of propane is added as a refrigerant and entrainer in the reaction raw materials, which reduces the reaction temperature and reduces the occurrence of side reactions. Through the hydrocyclone separation of the horizontal tank, the efficient separation of acid hydrocarbons is realized, and the corrosion of equipment is reduced. The alkylated oil produced by the reaction has a high octane number, low sulfur, and does not contain aromatics and olefins.

Description of drawings

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments. The scope of protection of the present invention is not limited to the expression of the following content.

Fig. 1 is the microchannel reactor structure schematic diagram that the present invention uses.

Fig. 2 is a schematic flow chart of the alkylation reaction process of the present invention.

Fig. 3 is a sectional view of the tubular microchannel reaction zone of the present invention.

Fig. 4 is a sectional view of the surface microchannel reaction zone of the present invention.

Fig. 5 is a structural schematic diagram of another embodiment of the planar microchannel reaction zone of the present invention.

In the figure: 1. separation tank; 2. transition bed; 3. distribution plate; 4. microchannel bed; 5. microchannel module; 6. acid distributor; 7. hydrocarbon distributor; 8. nitrogen inlet pipe; 9. Acid inlet pipe; 10. Hydrocarbon inlet pipe; 11. Top sparger; 12. Interface meter; 13. Sampling pipe; 14. Refrigerant inlet; 18. Acid extraction port; 19. Fiber material; 20. Support rib; 21. Constraint frame; 22. Microchannel panel.

detailed description

The present invention uses isobutane and olefins as raw materials and liquid acid as a catalyst to carry out alkylation reaction to obtain alkylated oil; the alkylation reaction adopts the following microchannel reactor: the microchannel reaction zone in the microchannel reactor is vertical The microchannel reaction zone is provided with at least one tubular microchannel reaction zone and one surface microchannel reaction zone (plate microchannel reaction zone). The vertical arrangement of the microchannel reaction zone refers to the vertical arrangement of the reaction channel.

The tubular microchannel reaction zone and the planar microchannel reaction zone (plate microchannel reaction zone) are vertically arranged in series, preferably multiple tubular microchannel reaction zones and surface microchannel reaction zones (plate microchannel reaction zone) are arranged in series alternately. Generally speaking, preferably 2 to 10 tubular microchannel reaction zones and 2 to 10 planar microchannel reaction zones are arranged alternately and in series. Specifically, the number of microchannel beds is determined according to the processing capacity and residence time. The series arrangement refers to that the reaction materials pass through the tubular microchannel reaction zone and the planar microchannel reaction zone in sequence. The volume ratio of the space occupied by the tubular microchannel reaction zone and the planar microchannel reaction zone is 0.5-5:1, preferably 2-3:1.

A material introduction structure is arranged on the top of the microchannel reactor, and the material introduction structure includes a liquid feed port and a gas feed port, a feed distributor is arranged above the microchannel reaction area, and a post-reaction material collection structure is arranged at the bottom of the microchannel reactor. The liquid feed distributor (acid distributor 6 and hydrocarbon distributor 7) ensures that the liquid feed distribution reaches 30-200 points/m2, preferably 50-100 points/m2. In addition, liquid level detection and control devices, temperature detection and control devices, pressure detection and control devices, material gasification detection devices, etc. are installed as required.

The shape of the reactor shell is preferably a cylinder, and the reactor is placed vertically.

The microchannel reactor is a vertical reactor with an aspect ratio of 2-10, preferably 4-6.

In the microchannel reactor, a microchannel reaction zone is set under the distributor, and the microchannel reaction zone belongs to a vertical microchannel and consists of two structural microchannel components. The tubular microchannel reaction zone is composed of tubular microchannel components. Tubular microchannel components are composed of materials with dense fiber-like pore-like structures, which can be organic polymers such as glass fiber and polyethylene or inorganic materials. The cross-section of the tubular microchannel components can be in various suitable shapes, such as polygons, etc. , the diameter of the channel (equivalent to a circle) can be micron or millimeter, generally 0.5~10mm, preferably 2~5mm. Referring to Fig. 3, 19 is a fiber material; 20 is a support rib; 21 is a constraint frame (tube sheet). The fiber material 19 has a dense pore-like structure, which can be organic polymers such as glass fiber and polyethylene or inorganic substances, etc., and has corrosion resistance to ensure service life. The fiber material is processed into a fiber cloth of a suitable shape and filled into the tube bundle on the constraining frame. The cross-section of the formed microchannel can be in various suitable shapes, such as polygonal, etc. The equivalent diameter of the channel is micron or millimeter, generally 0.5~10mm, preferably 2~5mm.

The surface microchannel reaction zone (plate microchannel reaction zone) is composed of surface microchannel components. Surface-type microchannel components are composed of multiple groups of plates installed vertically, which can be specific structures such as ring plate type and folded plate type. The surface channel gap between two plates is micron or millimeter level, generally 0.1-10mm, preferably 0.5-2mm , the gap between the two plates constitutes the surface microchannel reaction space. When the folded plate structure is adopted, the angle a between the two plates is between 5° and 180°, preferably between 10° and 60°. Referring to Figure 4, preferably, the surface microchannel member is set to have an indirect heat exchange structure, that is, the structure is similar to a conventional plate heat exchanger structure, but the reaction channel is a surface microchannel structure, and the introduction of cooling medium is beneficial to the heat of reaction. take out.

The bottom of the microchannel reactor communicates with the horizontal separation tank. The material inlet of the horizontal separation tank is preferably set as a cyclone separation structure.

A liquid level gauge is installed on the outer wall of the shell between the microchannel reactor distributor and the reaction bed to detect whether there is a liquid layer on the surface of the packing of the acid-hydrocarbon mixture, and to adjust the amount of acid feed.

A gas phase sampling device is installed on the outer wall of the shell between the reaction beds of the microchannel reactor to determine whether there is gas resistance.

The bed height of each section of the microchannel reactor is 30-200cm, preferably 50-150cm.

The upper end and the lower end of each section of the microchannel in the microchannel reactor are separated by a porous steel plate, and the opening ratio of the steel plate (the ratio of the open area of the steel plate to the steel plate) is 10% to 60%, preferably 15% to 30%.

The alkylation process used in the present invention is to use the microchannel reactor of the present invention, use isobutane and olefins as raw materials, propane as refrigerant and entrainer, and use liquid acid as a catalyst to carry out alkylation reaction to obtain alkyl carburetion. Olefins are C3-C5 olefins, preferably butene.

The alkylation process of the invention reduces the acid consumption, improves the selectivity and yield of the reaction process, and simultaneously improves the octane number of the alkylated oil. The reaction pressure (gauge pressure) is maintained at 0MPa~1.0MPa, preferably 0MPa~0.5MPa. The residence time of the reaction materials in the reactor is 1-200 min, preferably 30-90 min.

In the alkylation process of the present invention, the molar ratio of isobutane to olefin (alkene molar ratio) is 1-50:1, preferably 5-20:1.

In the alkylation reaction method of the present invention, the acid-hydrocarbon volume ratio is 0.1-5:1, preferably 0.5-3:1. Acid refers to liquid catalysts including various acids and ionic liquids.

In the alkylation process of the present invention, the molar ratio of isobutane to propane is 1-100:1, preferably 10-30:1. In the microchannel reactor of the present invention, the bed pressure drop of the microchannel alkylation reactor is small, which is beneficial to the endothermic vaporization of propane and reduces the hot spot of reaction.

As shown in Fig. 1 and Fig. 2, microchannel reactor comprises feed zone, microchannel reaction zone, settling zone and separation zone; The outlet of described feed zone communicates with the entrance of microchannel reaction zone; The microchannel reaction zone The outlet of the zone communicates with the inlet of the settling zone; the outlet of the settling zone communicates with the inlet of the separation zone.

The feeding area comprises a top distributor 11; the top distributor 11 is provided with an acid inlet pipe 9, a nitrogen inlet pipe 8 and a hydrocarbon inlet pipe 10; the top distributor 11 inner cavity is provided with an acid distributor 6 and Hydrocarbon distributor 7; the outlet of the acid inlet pipe 9 communicates with the inlet of the acid distributor 6; the outlet of the hydrocarbon inlet pipe 10 communicates with the inlet of the hydrocarbon distributor 7. An interface meter 12 is provided on the top distributor 11 .

The microchannel reaction zone includes a tubular microchannel reaction zone, a surface microchannel reaction zone, a tubular microchannel reaction zone, a surface microchannel reaction zone and a tubular microchannel reaction zone vertically alternately arranged in series with five segments. 13 is a sampling tube; 14 is a refrigerant inlet; 15 is a thermocouple sleeve; 3 is a distribution plate; 4 is a microchannel bed; 5 is a microchannel module. The settlement zone is the transition bed 2. The separation zone is the separation tank 1. The separation tank 1 is provided with a gas phase extraction port 16 , an acid extraction port 18 and a hydrocarbon extraction port 17 .

After the raw material enters the reactor, it will be evenly distributed through the acid distributor 6 and the hydrocarbon distributor 7. The distributor ensures that the distribution of the liquid feed reaches 30-200 points/m2, preferably 50-100 points/m2. A microchannel reaction zone is set under the distributor. The microchannel reaction zone belongs to a vertical microchannel and consists of two parts. It consists of installed folded plates, and the angle a between the two plates is between 10° and 60°. It has the effects of redistribution, mixing, and reaction.

Referring to Fig. 2, Fig. 2 is a schematic flow diagram of an alkylation process using a microchannel reactor provided by an embodiment of the present invention.

Adopt the microchannel reactor of the present invention, take isobutane and olefin as the raw material of the alkylation reaction, the catalyst adopts the liquid acid catalyst, the reaction raw material enters the distributor (hydrocarbon distributor) of the reaction device through the liquid feed port after passing through the buffer tank 7) Among them, the acid catalyst enters the acid distributor 6 of the reaction device through the liquid feed port, and a considerable amount of propane is added to the raw material as the refrigerant and entrainer of the raw material to realize the vaporization of the raw material to obtain heat and ensure the reaction temperature Low, the amount of raw material and acid catalyst is controlled by the flow rate regulation. After the initial distribution of the liquid distributor, according to a certain liquid hourly space velocity, it flows down evenly in a trickle state and enters the reaction bed. After the reaction raw materials can evenly enter the microchannel reaction zone, the reaction is first carried out in the tubular microchannel reaction zone at the upper end of the microchannel. The large specific surface area provided by the tubular microchannel reaction zone is conducive to the alkylation reaction and does not Channeling will occur. Then, the fluid is mixed, redistributed, and reacted through the surface microchannel reaction zone at the lower end of the microchannel. The raw materials are well mixed in the microchannel, the temperature is precisely controlled during the reaction process, the ratio of the raw materials is precisely controlled, and the yield of the product is obviously increased.

After the material reacts in the microchannel reaction zone, it enters the settling section, and the reaction material is separated by settling. Because the boiling points of propane and isobutane are different, as the pressure changes, the propane in the middle of the settling section takes heat and gradually vaporizes, and reaches the lower part of the settling section. Propane is vaporized, and part of isobutane is also vaporized. The reaction materials are settled and stratified, and enter the horizontal separation tank (in order to strengthen the separation effect, a horizontal separation tank with hydrocyclone separation function can be used in the specific design), and the lower layer of acid catalyst The upper layer gas is discharged through the compressor, the middle layer product is pumped out into the coalescence separator, the separated product is sent to the separation section or storage tank, and a small amount of acid is returned to the reactor.

The liquid catalyst used in the alkylation reaction can be any liquid acid catalyst that can catalyze the alkylation reaction of isobutane and olefins, specifically one or more of the liquid catalysts such as HF, H2SO4, phosphoric acid, boric acid, acetic acid or ionic liquid. kind.

The reaction effects of the present invention are illustrated below in conjunction with examples, but the protection scope of the present invention is not limited thereby.

Embodiment 1~3.

Using the reactor with the structure shown in Figure 1 and the alkylation reaction process shown in Figure 2, the bed pressure drop in the microchannel reaction zone is 0.1~1.0MPa, preferably 0~0.5MPa. Using isobutane and butene as raw materials, sulfuric acid as catalyst, and propane as refrigerant for alkylation reaction.

The acid hydrocarbon volume ratio of the sulfuric acid feed to the mixture feed of isobutane and butene is 0.1-5:1, preferably 0.5-3:1. The molar ratio of alkene is 1-50:1, preferably 5-20:1. The molar ratio of isobutane to propane is 1~100:1, preferably 10~30:1, and the reaction pressure is maintained at 0MPa~1.0MPa, preferably 0MPa~0.5MPa. The side reaction is suppressed, the acid consumption is reduced, the selectivity and yield of the reaction process are improved, and the octane number of the alkylated oil is improved at the same time. The residence time of the reaction materials in the reactor is 1-200 min, preferably 30-90 min.

The reactor structure is: "tubular microchannel reaction zone-surface microchannel reaction zone-tubular microchannel reaction zone-surface microchannel reaction zone-tubular microchannel reaction zone" five-section structure, and the volume of each microchannel reaction section is the same. The channel size of the tubular microchannel member is 3mm, the angle between the two plates of the planar microchannel member is 45°, and the gap between the two plates is 1mm.

The specific reaction conditions are shown in Table 1, and the reaction results are shown in Table 2.

Comparative example 1~2.

Comparative Example 1 adopts a conventional horizontal mechanically stirred reactor with a refrigeration tube bundle installed inside, and Comparative Example 2 adopts a microchannel reactor that only has a tubular microchannel member (same as Example 1). The reaction conditions are shown in Table 1, and the reaction results are shown in Table 1. Table 2.

Table 1 Main conditions of the alkylation reaction of the examples and comparative examples.

Table 2 Alkylation results of Examples and Comparative Examples.

It can be understood that the above specific descriptions of the present invention are only used to illustrate the present invention and are not limited to the technical solutions described in the embodiments of the present invention. Those of ordinary skill in the art should understand that the present invention can still be modified or Equivalent replacements to achieve the same technical effect; as long as they meet the needs of use, they are all within the protection scope of the present invention.

Claims (9)

1. a kind of alkylation using new micro passage reaction, using iso-butane and alkene as raw material, using liquid acid as catalyst, it is alkylated reaction and obtains alkylate oil；It is characterized in that：After the microchannel reaction zone that the raw material and catalyst enter in micro passage reaction is alkylated reaction, enters back into settling section and carry out sedimentation layering；Reaction mass continues into horizontal knockout drum after sedimentation is layered, extracts lower catalyst agent out, discharge top tank air, middle level product is delivered to coalescing separator and separated again.

2. the alkylation according to claim 1 using new micro passage reaction, it is characterised in that：Propane is added in the raw material, cryogen and entrainer as raw material.

3. the alkylation according to claim 2 using new micro passage reaction, it is characterised in that：The micro passage reaction includes feed zone, microchannel reaction zone, decanting zone and Disengagement zone；The outlet of the feed zone communicates with the entrance of microchannel reaction zone；The outlet of the microchannel reaction zone communicates with the entrance of decanting zone；The outlet of the decanting zone communicates with the entrance of Disengagement zone.

4. the alkylation according to claim 3 using new micro passage reaction, it is characterised in that：The microchannel reaction zone declines pathway reaction area at least provided with a tubular type microchannel reaction zone and a face.

5. the alkylation according to claim 4 using new micro passage reaction, it is characterised in that：Tubular type microchannel reaction zone and face are declined, and longitudinally alternating is arranged in series in pathway reaction area；The number of tubular type microchannel reaction zone is 2~10；The face decline pathway reaction area number be 2~10.

6. the alkylation according to claim 5 using new micro passage reaction, it is characterised in that：Tubular type microchannel reaction zone and face the spatial volume ratio that pathway reaction area occupies that declines are 0.5~5：1.

7. the alkylation according to claim 6 using new micro passage reaction, it is characterised in that：Tubular type microchannel reaction zone is made up of tubular type microchannel component；Channel diameter is 0.1~10mm；The face pathway reaction area that declines is made up of the face channel component that declines；Path clearance is 0.1~10mm between two plates.

8. the alkylation according to claim 7 using new micro passage reaction, it is characterised in that：The reaction pressure of alkylated reaction is 0MPa~1.0MPa；Residence time of the reaction mass in reactor is 1~200min.

9. according to any described alkylation using new micro passage reaction of claim 2~8, it is characterised in that：The iso-butane of alkylated reaction and the mol ratio of alkene are 1~50:1；Sour hydrocarbon volume ratio is 0.1~5:1；Iso-butane is 1~100 with propane mol ratio:1.