CN111617703A

CN111617703A - Hydrogenation ware entry diffuser

Info

Publication number: CN111617703A
Application number: CN202010394940.9A
Authority: CN
Inventors: 邓矛; 陈崇刚; 李立权; 晁君瑞
Original assignee: China Petroleum and Chemical Corp; Sinopec Engineering Group Co Ltd; Sinopec Guangzhou Engineering Co Ltd
Current assignee: China Petroleum and Chemical Corp; Sinopec Engineering Group Co Ltd; Sinopec Guangzhou Engineering Co Ltd
Priority date: 2020-05-12
Filing date: 2020-05-12
Publication date: 2020-09-04
Anticipated expiration: 2040-05-12
Also published as: CN111617703B

Abstract

The invention discloses an inlet diffuser of a hydrogenation reactor, which comprises an inlet conical body, a mounting plate and an injection cover, wherein the inlet conical body is provided with a conical surface; the inlet conical body is a conical frustum-shaped body, a cyclone tube is uniformly distributed on the upper surface of the inlet conical body, the upper part of the cyclone tube is of an inverted cone-shaped closing-up structure, the lower part of the cyclone tube is a guide tube for guiding, the outlet of the guide tube is fixed on the lower surface of the inlet conical body, and a rotary guide vane is arranged in the inverted cone-shaped closing-up structure; the mounting plate is a circular annular plate, and the inner ring of the mounting plate is welded and fixed on the outer wall of the inlet conical body; the spraying cover is a spherical surface or an ellipsoidal surface, spraying holes are uniformly distributed on the spraying cover, and the spraying cover is fixedly arranged at the lower part of the inlet conical body. The invention can fully mix gas and liquid, has large spraying area, effectively avoids liquid phase bias flow, can greatly improve the initial distribution of oil gas entering the reactor, improves the reaction operation condition and improves the product quality.

Description

Hydrogenation ware entry diffuser

Technical Field

The invention relates to the technical field of diffusers, in particular to a diffuser at an inlet of a hydrogenation reactor.

Background

In recent years, with the gradual upgrade of quality standards of petrochemical products and the stricter of environmental regulations, the hydrogenation technology plays an increasingly important role in the oil refining industry, and in addition, the requirement of 'eating, drying and squeezing out' of raw oil, and oil refining enterprises at home and abroad rapidly expand the hydrotreating capability of various oil products in order to improve the economic benefit and meet the requirement of environmental protection.

The key core equipment of hydrotreating is a hydrogenation reactor, and inside the hydrogenation reactor, a mixture of hydrogen and raw oil in a certain proportion is subjected to various hydrogenation reactions under the action of a catalyst at a certain temperature and pressure. Because the hydrogenation reaction is a strong exothermic reaction existing in three phases of gas, liquid and solid, if the gas and the liquid are not uniformly distributed in a catalyst bed, the reaction of a part with a large amount of liquid phase is violent, the generated heat is large, the local temperature of the catalyst is high, and a hot spot is formed, so that the catalyst is inactivated prematurely, local coking and hardening of the catalyst are caused in serious conditions, and materials cannot normally pass through, so that the service life of the catalyst and the start-up period of the device are reduced, the pressure drop of the bed is increased, and the energy consumption of the device is increased. Therefore, in order to make the hydrogenation apparatus operate smoothly, the temperature difference in the radial direction of the reactor needs to be small, in other words, the liquid distribution in the radial direction of the reactor needs to be as uniform as possible. With the upsizing of equipment caused by the upsizing of the device, the radial temperature difference of the reactor with larger diameter is kept small, and new challenges are provided for the internal components of the hydrogenation reactor.

Fixed bed hydrogenation reactors, a common type of hydrogenation reactor, are typically internally provided with reactor internals such as inlet diffusers, scale depositing baskets, distribution trays, catalyst support grids, discharge tubes, hydrogen cooling tanks, thermocouple protection tubes, and outlet collectors. The fixed bed hydrogenation reactor is generally fed from the top center of the hydrogenation reactor, because the diameter of the reactor inlet is usually smaller than that of the reactor, a gas-liquid two-phase medium from the reactor inlet needs to enter the reactor through an inlet diffuser, and the inlet diffuser has the functions of mixing the gas phase and the liquid phase on one hand, and dispersing the gas phase and the liquid phase into the reactor to realize pre-distribution of the gas phase and the liquid phase, so the inlet diffuser plays an important role in internal parts of the hydrogenation reactor and uniform distribution of the medium. With the upsizing of equipment caused by the upsizing of the device, the increase of the diameter of the reactor inlet has certain limitation, so that the ratio of the diameter of the reactor to the diameter of the reactor inlet reaches 5 or more, and higher requirements are put forward on an inlet diffuser of a hydrogenation reactor.

Present common diffuser is mostly simple two-layer or multilayer conical body, the gas-liquid is double-phase to be short through the conical body time, mix insufficiently, the conical body leads to the material to be the tilt line at the streamline that reactor head space formed simultaneously, the liquid layer on the material distributes the dish with the top is rushed to the reactor all around and is sent, form "push away unrestrained" phenomenon, reactor distribution dish liquid layer height presents from central point to border position and increases the distribution promptly, reactor distribution dish central point puts the liquid level less, there is not the liquid layer even, reactor boundary wall department liquid layer height is big, cause the whole cross-section of material evenly distributed to the reactor that can not be better after the reposition of redundant personnel, there is more serious deviation in the distribution.

Patent publication No. CN202015610U discloses an inlet diffuser for a hydrogenation reactor. The structure mainly comprises an outer cylinder body, a spherical spray head, a hemispheroid, a pipe flange and a flow crushing plate, wherein the spherical spray head, the hemispheroid and the flow crushing plate play a role in slowing down the impact force of fluid, and a medium is sprayed into a reactor through a flow crushing hole connecting pipe on the flow crushing plate. Although the diffuser can slow down the vertical impact force of materials to a certain degree, the gas-liquid two phases mainly spray media into the reactor through the crushed flow hole connecting pipe vertical to the crushed flow plate, the spraying area is small, and meanwhile, the gas-liquid two phases pass through the nozzle once and the connecting pipe twice, and the pressure drop is large. In addition, the use of the hydrogenation reactor with a larger diameter is also limited, because the gas-liquid two-phase feeding amount is increased after the scale of the device is increased, but because the size of the inlet pipe is smaller, the flow velocity of the gas-liquid two-phase in the inlet pipe and at the outlet of the spray head is very high, on one hand, the impact on the semisphere is very large, on the other hand, the impact counter force and the vibration of the inlet pipe are also very large, and the sealing of the pipe flange is easy to lose.

Patent No. CN106268524A discloses a diffuser and a fixed bed reactor. This diffuser mainly includes structures such as barrel, whirl board, well core rod, and the whirl board is fixed at the barrel middle part through well core rod, and the whirl board presents the curved plate that the heliciform extends for following the barrel axial. The gas-liquid material entering the diffuser flows in the cylinder along the extending direction of the rotational flow plate and is diffused along the direction at the gas-liquid material diffusion opening. Although this diffuser enables the gas-liquid material and produces certain mixture, and the pressure drop is less, but the material mainly flows and diffuses along the extending direction of whirl board, leads to the material to concentrate, spray the area little, easily appears local high concentration and most low concentration region.

In order to enable gas-liquid two-phase feeding to be more uniformly dispersed into the reactor, avoid the phenomenon of 'pushing waves', enlarge the spraying area of the gas-liquid two-phase, promote the mixing of the gas-liquid two-phase, enable the gas-liquid two-phase to react with a catalyst more stably and promote the stable operation of a hydrogenation device, a novel hydrogenation reactor inlet diffuser is needed.

Disclosure of Invention

The invention provides an inlet diffuser of a hydrogenation reactor, aiming at solving the technical problems that the inlet diffuser of the fixed bed hydrogenation reactor in the prior art is small in liquid phase distribution area, uneven in radial liquid phase distribution, easy to cause flow deviation and wall flow and the like.

The invention provides an inlet diffuser of a hydrogenation reactor, which comprises an inlet conical body, a mounting plate and an injection cover; the inlet conical body is a conical frustum-shaped body, a cyclone tube is uniformly distributed on the upper surface of the inlet conical body, the upper part of the cyclone tube is of an inverted cone-shaped closing-up structure, the lower part of the cyclone tube is a guide tube for guiding, the outlet of the guide tube is fixed on the lower surface of the inlet conical body, and a rotary guide vane is arranged in the inverted cone-shaped closing-up structure; the mounting plate is a circular annular plate, and the inner ring of the mounting plate is welded and fixed on the outer wall of the inlet conical body; the spraying cover is a spherical surface or an ellipsoidal surface, spraying holes are uniformly distributed on the spraying cover, and the spraying cover is fixedly arranged at the lower part of the inlet conical body.

The spiral-flow tube that sets up in the entry conical body is 4 ~ 90, and the main aspects trompil diameter 10 ~ 200mm of back taper binding off structure is preferably 12 ~ 100mm, and the tip trompil diameter after binding off is 5 ~ 100mm, preferably 8 ~ 50 mm. The gas-liquid two-phase medium is in the cyclone tube, as the flow area is reduced, the flow speed is increased, the flowing turbulence degree is increased, and the mixing of the gas phase and the liquid phase is promoted; the gas-liquid two-phase contact time and the pressure drop of the inlet diffuser are comprehensively considered, and the distance between every two adjacent rotary guide vanes is 1.1-5 times of the diameter of the small end opening. The swirl tube lower part is the stand pipe, and the stand pipe can be the straight tube, also can be the return bend, and such purpose is through the guide effect of stand pipe, ensures the gas-liquid two-phase even dispersion on spraying the whole region that covers from the swirl tube outflow.

The injection cover is evenly provided with injection holes on the circumference along the radial direction, the injection holes are distributed in a concentric circle shape, the mixed medium is sprayed out from the injection holes to the periphery, and the diameter of the injection holes is preferably 5-50 mm. The spraying cover is arranged to be spherical or ellipsoidal, which has the advantages of wide spraying range, capability of uniformly spraying the mixed medium to the periphery, increase of the contact area between the medium and the catalyst in the reactor, and promotion of uniform distribution of the medium in the reactor. The principle of the hole opening of the jet hole is to ensure enough spraying area and to ensure the uniform distribution of the gas-liquid medium on the cross section of the reactor.

As an improved scheme, a partition plate can be arranged on the spray hood and can be divided into an annular partition plate and a vertical partition plate. The annular partition plates are distributed in a concentric circle shape around the center of the injection cover, the annular partition plates divide the injection cover into annular areas containing injection holes with different numbers, vertical partition plates which are vertically crossed with the annular partition plates along the radial direction of the injection cover can also be arranged on the injection cover, and the annular areas are further divided into fan-shaped areas with smaller areas and containing the injection holes with different numbers. The height of the partition plate is 5-200 mm, and the partition plate has the function of ensuring that each area on the spraying cover stores certain liquid. When the liquid in a certain area is too high, the liquid overflows to other areas through the partition plate, so that the free flow and uniform distribution of the liquid on the injection cover are realized, the inlet diffuser is ensured to uniformly flow out of the liquid phase to the radial section of the reactor, and the bias flow is avoided.

According to the condition of processing raw materials (mainly considering fluidity), holes can be formed in the partition plate or not, the raw materials with good fluidity can not be formed, the raw materials with poor fluidity can be formed with holes, and the holes are preferably round holes or slots.

As a further improvement, the gas-liquid spray head can be arranged at the spray hole on the spray cover, the gas-liquid spray head arranged on the spray cover can increase the range of spraying the medium to the periphery, and simultaneously, the contact of gas and liquid phases is increased. The outlet type of the gas-liquid spray head can be an expanding type, a flat type or a closing type so as to ensure that the gas-liquid spray heads at different positions can uniformly distribute the medium to the cross section of the reactor.

The gas-liquid nozzle is fixed at the injection hole part by a tangent plane perpendicular to the injection hole part, the gas-liquid nozzle is a tubular body with two open ends, round holes or slots can be uniformly arranged on the pipe wall of the gas-liquid nozzle on the inner side of the injection cover along the circumferential direction to serve as fluid channels, the round holes or the slots can be one layer or two layers or multiple layers, and the diameter of the round holes is 2-30 mm, preferably 4-25 mm. Generally, due to the gravity difference between the gas phase and the liquid phase, the liquid phase accumulated by the partition plate enters the gas-liquid spray head from single-row or multi-row openings on the gas-liquid spray head, the gas phase enters from the top of the gas-liquid spray head and is further contacted and cut with the liquid phase entering from the openings, and the gas phase and the liquid phase are more fully mixed. Under extreme circumstances, the liquid phase also can get into from the gas-liquid shower nozzle top, and the liquid phase leaves with higher speed, and such beneficial part is the mixture that further increases gas-liquid two-phase medium, and the gas-liquid shower nozzle has great operation elasticity simultaneously, and the higher region of liquid level can flow to other regions through the overflow on the one hand, also can leave the injection cover fast from the gas-liquid shower nozzle top, guarantees to spray to cover and all have more even liquid height in every district that is separated by the baffle.

The working principle of the invention is as follows:

the medium from the hydrogenation reactor inlet enters the inlet diffuser through the inlet of the inlet conical body cyclone tube, the mixed medium is rectified in the cyclone tube through the cyclone effect of the rotary guide vanes, the contact time of gas phase and liquid phase is increased, the medium is further uniformly dispersed in the whole area on the injection cover through the guide effect of the guide tube, and the medium entering the upper space of the injection cover is radially and uniformly distributed in the reactor through the injection effect of the gas-liquid spray nozzle and enters the catalyst bed layer.

The invention has the following beneficial effects:

1) oil gas leaves the space between the injection cover and the inlet conical body after entering the inlet conical body, and because the sectional area is increased, the flow velocity of fluid is reduced, the pressure is increased, a pressurizing chamber is formed at the position, the pressure of a mixed medium is increased by utilizing the conversion of the kinetic energy and the pressure of the medium, and the uniform ejection of the medium is facilitated.

2) The inlet of the cyclone tube is in an inverted cone shape or an inverted trumpet shape, so that the mixed medium is accelerated; the inlet of the swirl tube is provided with the rotary guide vane to realize rectification of the mixed medium, increase the turbulence degree of the flow and promote the mixing of gas phase and liquid phase; the guiding action of the guide tube ensures that the liquid phase is uniformly distributed over the entire spray hood.

3) The range of medium injection is increased and the contact area of the medium and the catalyst in the reactor is increased through the injection cover with the spherical surface or the ellipsoidal surface; the flow of the liquid phase is strictly and accurately controlled through the separation effect of the partition plate on the injection cover, so that the liquid phase is ensured to exist in each area, and the bias flow is avoided from the source; the gas-liquid spray heads are arranged on the spray cover, and liquid phase in each area enters the reactor from the gas-liquid spray heads, so that the mixing of gas phase and liquid phase can be further promoted, and the operation flexibility is high.

In a word, the invention can fully mix gas and liquid, has large spraying area, effectively avoids liquid phase bias flow, can greatly improve the initial distribution of oil gas entering a reactor, improves the reaction operation condition and improves the product quality.

Drawings

FIG. 1 is a schematic view of the inlet diffuser of the present invention;

FIG. 2 is a schematic view of the structure of the spray hood;

FIG. 3 is a schematic view of the structure of the gas-liquid shower head and its assembly structure;

fig. 4 is a schematic view of the assembled structure of the inlet diffuser of the present invention.

In the figure: 1-inlet conical body, 2-mounting plate, 3-injection cover, 4-annular partition plate, 5-gas-liquid spray head, 6-cyclone tube, 7-rotary guide vane, 8-injection hole, 9-vertical partition plate, 10-round hole, 11-reactor inlet and 12-reactor shell.

Detailed Description

The invention will be further explained with reference to the drawings.

As shown in fig. 1, the hydrogenation reactor inlet diffuser of the present invention mainly comprises an inlet cone 1, a mounting plate 2 and an injection hood 3; the inlet conical body 1 is a conical frustum, the upper surface of the inlet conical body is uniformly provided with a cyclone tube 6, the upper part of the cyclone tube 6 is of an inverted cone closing-in structure, the lower part of the cyclone tube 6 is provided with a guide tube for guiding, the outlet of the guide tube is fixed on the lower surface of the inlet conical body 1, and a rotary guide vane 7 is arranged in the inverted cone closing-in structure; the mounting plate 2 is a circular annular plate, and the inner ring of the mounting plate is welded and fixed on the outer wall of the inlet conical body 1; the injection cover 3 is a spherical surface or an ellipsoidal surface, spray holes are uniformly distributed on the injection cover 3, and the injection cover 3 is fixedly arranged at the lower part of the inlet conical body 1. The inner side of the injection cover 3 is provided with an annular clapboard 4 and the injection hole is provided with a gas-liquid nozzle 5.

As shown in fig. 2, the injection holes 8 are uniformly distributed on the injection cover, the annular partition plate 4 which is arranged in a concentric circle shape and the vertical partition plate 9 which is vertically crossed with the annular partition plate 4 along the radial direction of the injection cover divide the injection cover into different fan-shaped areas. Of course, the annular partition plate and the vertical partition plate can also be provided with holes, and the holes can be round holes or slots.

As shown in fig. 3, the gas-liquid shower nozzle 5 is disposed at the injection hole of the injection cap 3, and a circular hole 10 serving as a fluid passage is disposed on a pipe wall of the gas-liquid shower nozzle 5, but the fluid passage may be formed in a slit shape, and an outlet pattern of the gas-liquid shower nozzle 5 in the drawing is a flat type.

As shown in fig. 4, the inlet diffuser of the present invention is installed at the reactor inlet 11 of the reactor housing 12, and the inlet diffuser is fixed to the lower portion of the reactor inlet 11 by the installation plate 2.

The working process of the invention is as follows: as shown in fig. 4 and 1, the arrows indicate the flow direction of the medium in the cyclone tube 6. Reaction medium external to the hydrogenation reactor enters the inlet diffuser of the present invention via the hydrogenation reactor inlet 11. Firstly, a medium enters an inlet diffuser through an inlet of a cyclone tube 6 of an inlet conical body 1, the rectification of a mixed medium is realized through the cyclone effect of a rotary guide vane 7 in the cyclone tube 6, the contact time of a gas phase and a liquid phase is increased, the medium is further uniformly dispersed in the whole area on a spray cover 3 through the guide effect of the guide tube, the medium entering the upper space of the spray cover 3 is uniformly distributed in a fan-shaped area divided by an annular partition plate 4 and a vertical partition plate 9, and the medium is sprayed out by a gas-liquid spray nozzle 5 and uniformly enters a catalyst bed layer in a reactor.

Claims

1. A hydrogenation reactor inlet diffuser characterized by: comprises an inlet cone, a mounting plate and an injection cover; the inlet conical body is a conical frustum-shaped body, a cyclone tube is uniformly distributed on the upper surface of the inlet conical body, the upper part of the cyclone tube is of an inverted cone-shaped closing-up structure, the lower part of the cyclone tube is a guide tube for guiding, the outlet of the guide tube is fixed on the lower surface of the inlet conical body, and a rotary guide vane is arranged in the inverted cone-shaped closing-up structure; the mounting plate is a circular annular plate, and the inner ring of the mounting plate is welded and fixed on the outer wall of the inlet conical body; the spraying cover is a spherical surface or an ellipsoidal surface, spraying holes are uniformly distributed on the spraying cover, and the spraying cover is fixedly arranged at the lower part of the inlet conical body.

2. The hydrogenation reactor inlet diffuser of claim 1 wherein: the quantity of whirl pipe is 4 ~ 90, and the main aspects trompil diameter 10 ~ 200mm of back taper binding off structure, and the tip trompil diameter after the binding off is 5 ~ 100 mm.

3. The hydrogenation reactor inlet diffuser of claim 2 wherein: the diameter of a large-end opening of the inverted cone-shaped closing-up structure is 12-100 mm, and the diameter of a small-end opening after closing up is 8-50 mm.

4. The hydrogenation reactor inlet diffuser of claim 1 wherein: the distance between two adjacent rotary guide vanes is 1.1-5 times of the diameter of the small end opening.

5. The hydrogenation reactor inlet diffuser of claim 1 wherein: the injection cover is provided with an annular partition plate, the annular partition plate is concentrically distributed around the center of the injection cover, and the annular partition plate divides the injection cover into annular areas containing injection holes with different numbers.

6. The hydrogenation reactor inlet diffuser of claim 5 wherein: the injection cover is provided with a vertical partition plate which is vertically crossed with the annular partition plate along the radial direction of the injection cover, and the annular area is divided into fan-shaped areas with smaller area and containing injection holes with different numbers.

7. The hydrogenation reactor inlet diffuser of claim 6 wherein: the annular partition plate and the vertical partition plate are provided with holes.

8. The hydrogenation reactor inlet diffuser of any one of claims 1 to 7, wherein: and the gas-liquid spray head is arranged at the spray hole on the spray cover and is vertical to the tangent plane at the spray hole.

9. The hydrogenation reactor inlet diffuser of claim 8 wherein: the gas-liquid spray head is a tubular body with two open ends, round holes or slots are uniformly arranged on the pipe wall of the gas-liquid spray head positioned on the inner side of the injection cover along the circumferential direction to serve as fluid channels, and the round holes or the slots are one layer or two layers or multiple layers.