WO2025007792A1 - 包含液体分布装置的固定床反应器和使用这种反应器进行多相催化反应的方法 - Google Patents

包含液体分布装置的固定床反应器和使用这种反应器进行多相催化反应的方法 Download PDF

Info

Publication number
WO2025007792A1
WO2025007792A1 PCT/CN2024/101844 CN2024101844W WO2025007792A1 WO 2025007792 A1 WO2025007792 A1 WO 2025007792A1 CN 2024101844 W CN2024101844 W CN 2024101844W WO 2025007792 A1 WO2025007792 A1 WO 2025007792A1
Authority
WO
WIPO (PCT)
Prior art keywords
heat exchange
liquid
reactor
exchange tube
reaction
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/CN2024/101844
Other languages
English (en)
French (fr)
Inventor
周继鹏
何文军
俞峰萍
戈军伟
王嘉华
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
China Petroleum and Chemical Corp
Sinopec Shanghai Research Institute of Petrochemical Technology
Original Assignee
China Petroleum and Chemical Corp
Sinopec Shanghai Research Institute of Petrochemical Technology
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by China Petroleum and Chemical Corp, Sinopec Shanghai Research Institute of Petrochemical Technology filed Critical China Petroleum and Chemical Corp
Publication of WO2025007792A1 publication Critical patent/WO2025007792A1/zh
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J8/00—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes
    • B01J8/02—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with stationary particles, e.g. in fixed beds
    • B01J8/0285—Heating or cooling the reactor
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J8/00—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes
    • B01J8/02—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with stationary particles, e.g. in fixed beds
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J8/00—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes
    • B01J8/02—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with stationary particles, e.g. in fixed beds
    • B01J8/06—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with stationary particles, e.g. in fixed beds in tube reactors; the solid particles being arranged in tubes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J8/00—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes
    • B01J8/02—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with stationary particles, e.g. in fixed beds
    • B01J8/06—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with stationary particles, e.g. in fixed beds in tube reactors; the solid particles being arranged in tubes
    • B01J8/067—Heating or cooling the reactor
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C29/00—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring
    • C07C29/09—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring by hydrolysis
    • C07C29/10—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring by hydrolysis of ethers, including cyclic ethers, e.g. oxiranes
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C29/00—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring
    • C07C29/09—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring by hydrolysis
    • C07C29/10—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring by hydrolysis of ethers, including cyclic ethers, e.g. oxiranes
    • C07C29/103—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring by hydrolysis of ethers, including cyclic ethers, e.g. oxiranes of cyclic ethers
    • C07C29/106—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring by hydrolysis of ethers, including cyclic ethers, e.g. oxiranes of cyclic ethers of oxiranes
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C31/00—Saturated compounds having hydroxy or O-metal groups bound to acyclic carbon atoms
    • C07C31/18—Polyhydroxylic acyclic alcohols
    • C07C31/20—Dihydroxylic alcohols
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F1/00—Tubular elements; Assemblies of tubular elements
    • F28F1/10—Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F1/00—Tubular elements; Assemblies of tubular elements
    • F28F1/10—Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses
    • F28F1/12—Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses the means being only outside the tubular element
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F1/00—Tubular elements; Assemblies of tubular elements
    • F28F1/10—Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses
    • F28F1/42—Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses the means being both outside and inside the tubular element
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P20/00—Technologies relating to chemical industry
    • Y02P20/50—Improvements relating to the production of bulk chemicals
    • Y02P20/52—Improvements relating to the production of bulk chemicals using catalysts, e.g. selective catalysts

Definitions

  • the present invention relates to the technical field of multiphase catalytic reaction, and in particular to a reactor comprising a liquid distribution device and a method for performing multiphase catalytic reaction using the reactor.
  • Heterogeneous catalytic reaction refers to a chemical reaction of one or more reactants at an interface (such as on a solid catalyst surface). Heterogeneous catalytic reaction is usually carried out in a fixed bed reactor, a fluidized bed reactor, a moving bed reactor, a fed bed reactor and a rotating bed reactor.
  • Shell-and-tube fixed bed reactors are widely used in the chemical industry. They have the advantages of small size, high reaction rate, and easy control. Among them, shell-and-tube fixed bed reactors are mostly used in highly exothermic reaction systems.
  • the reactor structure is similar to a fixed tube sheet heat exchanger.
  • the tube side is the reaction zone.
  • the catalyst is loaded in the tubes. The material reacts when passing through the catalyst in the tubes.
  • the shell side space is filled with heat exchange medium to form a reaction heat exchange system.
  • Common applications of shell-and-tube fixed bed reactors include methanol synthesis towers, ethylene oxide reactors, acrylic acid reactors, and coal-to-ethanol reactors.
  • Sasol and Shell have successively developed fixed-bed reactors for industrial use in Fischer-Tropsch synthesis.
  • the reactor is filled with catalysts in the tubes, and water is placed between the tubes to generate steam to take the heat out of the reactor.
  • the Fischer-Tropsch reaction is a highly exothermic reaction, and there is temperature non-uniformity in both the radial and axial directions of the tubes in the fixed-bed reactor.
  • the current method for controlling the uniformity of the bed temperature is to reduce the diameter of the reaction tube, but in a smaller diameter, the synthesis gas is prone to carbon deposition on the catalyst surface, resulting in local overheating, causing the catalyst to rupture and deactivate.
  • CN101480595B proposes to use pin-shaped fin heat exchange tubes to take into account both flow field regulation and heat transfer enhancement.
  • the pin-shaped fins can reduce the liquid velocity and reduce axial back mixing.
  • the fins can increase the heat exchange area, and the secondary turbulence generated can increase the heat transfer coefficient, which can offset the adverse effect of the reduction in the convective heat transfer coefficient caused by the reduction in liquid velocity.
  • the collision between the pin-shaped fins and the catalyst particles will cause the problem of catalyst wear, which will reduce the catalyst reaction performance, weaken the separation efficiency of catalyst particles and liquid, and increase the frequency of catalyst replacement.
  • Heat exchange tubes with spiral fins are generally used for fluids with high flow rates, such as gas-solid reaction systems, because heat exchange tubes with spiral fins or threads disturb the high-speed flow of fluids, causing the fluid boundary layer to be continuously destroyed, which can effectively improve the heat transfer film coefficient and produce a good enhanced heat transfer effect.
  • Chinese patent application CN 209222077 discloses a heat transfer system for a Fischer-Tropsch synthesis reactor, which includes a heat exchange element and a steam drum, and the heat exchange element is arranged in the reactor; wherein the heat exchange tube can take three structural forms, the most commonly used is a smooth metal tube, and a metal tube with pin fins or/and a metal tube with an external thread groove can also be used; the Fischer-Tropsch synthesis reactor is a three-phase slurry bed Fischer-Tropsch synthesis reactor or a fluidized bed Fischer-Tropsch synthesis reactor.
  • Ethylene glycol is an aliphatic diol with important uses in the chemical industry.
  • Ethylene glycol is usually prepared by a multiphase catalytic hydration process in a fixed bed reactor.
  • Chinese patent application CN101306984A discloses a fixed bed reactor for catalytic hydration of ethylene oxide to produce ethylene glycol, wherein the catalyst is loaded on the outside of a U-shaped tube, so that the expansion problem after the catalyst is loaded and the heat transfer can be solved to a certain extent.
  • the U-shaped tube used is easy to cause the reaction liquid outside the tube to produce a channeling effect along the tube wall during the flow process, which will cause the liquid to produce an uneven distribution phenomenon in the radial direction of the fixed bed, and the disc-shaped redistributor has a limited effect on solving the channeling phenomenon.
  • the channeling phenomenon of the reaction liquid will affect the raw material conversion rate and selectivity.
  • the channeling effect causes the thickness of the liquid film on the outside of the U-shaped tube to be larger, which increases the heat transfer resistance and reduces the heat transfer capacity of the U-shaped tube.
  • the U-shaped tube adopts different specifications and the inlet and outlet ends are respectively located on both sides of the reactor.
  • the reactor bed will produce a temperature difference due to the distribution of the U-shaped tube, which will also affect the conversion rate and yield of the reaction. Thermal stress caused by temperature differences can also shorten the service life of the reactor.
  • the inventor surprisingly found that the above problems can be overcome by using a reactor containing a specific liquid distribution device, wherein the liquid distribution device contains a plurality of specifically arranged heat exchange tubes with outer wall spiral fins; the inventor found that when this reactor is used in a liquid-solid reaction system of a reaction liquid with a low flow rate, this liquid distribution device has a strong promoting effect on the liquid-solid reaction, significantly improving the reaction selectivity.
  • the inventor believes that when this specifically arranged heat exchange tube with outer wall spiral fins is used in a liquid-solid reaction system of a reaction liquid stream with a low flow rate, the main function of the outer wall spiral fins is to change the flow direction of the fluid, promote the flow of the fluid in the radial direction, make the fluid with almost equal residence time split and merge in the radial direction, prevent the fluid with different residence time from mixing back in the axial direction, so that the temperature distribution of the reaction material in the radial direction is uniform, and then accurately control the reaction process, thereby significantly improving the selectivity of the reaction.
  • one object of the present invention is to provide a reactor comprising a liquid distribution device, which can not only effectively avoid the problem of uneven fluid distribution in the solid particle loading area caused by the channeling phenomenon occurring on the outer wall of the heat exchange tube, but also effectively reduce the liquid film thickness of the laminar layer at the liquid-solid interface to enhance the reaction kinetics. In addition, it can also improve the uniformity of enhanced heat transfer on the outer wall and inner wall of the heat exchange tube, and reduce the heat transfer resistance, thermal stress and reactor pressure drop.
  • the present invention provides a reactor comprising a liquid distribution device,
  • a fixed bed reactor allows the reaction liquid to be evenly distributed in the radial direction of the reactor and always maintains a piston flow form, thereby reducing axial back mixing of the reaction liquid and reducing the pressure drop in the reactor.
  • it can effectively remove a large amount of heat released by the reaction system and reduce the temperature of the reaction hotspot, making the temperature distribution in the reactor uniform, thereby improving the inherent safety of the reactor.
  • the reactor including such a liquid distribution device, especially a fixed bed reactor is particularly suitable for processes such as reacting ethylene oxide (liquid) with water (liquid) under the action of a solid resin catalyst to generate ethylene glycol, reacting ethylene oxide (liquid) with ethylene glycol (liquid) under the action of a solid resin catalyst to generate diethylene glycol, reacting ethylene oxide (liquid) with diethylene glycol (liquid) under the action of a solid resin catalyst to generate triethylene glycol, reacting propylene oxide (liquid) with water (liquid) under the action of a solid resin catalyst to generate propylene glycol, and reacting butylene oxide (liquid) with water (liquid) under the action of a solid resin catalyst to generate butanediol. While ensuring uniform distribution of the reaction liquid, the heat generated by the reaction can be quickly removed, thereby ensuring uniform temperature distribution in the reaction zone, and the inherent safety of the chemical process can be guaranteed to a great extent.
  • the present invention provides a reactor, in particular a fixed bed reactor, comprising a liquid distribution device, wherein the liquid distribution device comprises:
  • a heat exchange tube unit comprising a plurality of vertically arranged heat exchange tubes, wherein at least a portion, preferably all of the heat exchange tubes are provided with left-handed or right-handed spiral fins on their outer walls, wherein the outer wall spiral fins of at least a portion of the heat exchange tubes rotate in opposite directions to the outer wall spiral fins of the adjacently arranged heat exchange tubes (i.e., the outer wall spiral fins of at least a portion of the adjacently arranged heat exchange tubes rotate in alternating left-handed and right-handed directions), and more preferably, the outer wall spiral fins of all the heat exchange tubes rotate in opposite directions to the outer wall spiral fins of the adjacently arranged heat exchange tubes (i.e., the outer wall spiral fins of all the adjacently arranged heat exchange tubes rotate in alternating left-handed and right-handed directions); a heat exchange medium flows in the heat exchange tubes, and a liquid reaction material flows outside the heat exchange tubes in a direction almost parallel to the axial direction of the heat exchange tubes;
  • the optional solid particle packing unit comprises solid particles filling the space between the heat exchange tubes.
  • the solid particle packing unit is a packed bed or a catalyst bed, more preferably a catalyst bed.
  • the present invention also provides a method for carrying out a heterogeneous catalytic reaction, especially a liquid-solid catalytic reaction, using the above reactor.
  • the inventors surprisingly found that the uniform distribution of the local temperature of the outer wall of the heat exchange tube can promote the uniform distribution of the reaction fluid; when the reactor including the liquid distribution device according to the present invention is used for liquid-solid reaction, due to the adjacent arrangement of the heat exchange tubes, the uniform distribution of the local temperature of the outer wall of the heat exchange tube can promote the uniform distribution of the reaction fluid;
  • the spiral fins on the outer wall of the heat pipe are alternating between left-handed and right-handed.
  • the liquid reaction materials are continuously divided and merged under the combined guidance of the left-handed and right-handed outer wall spiral fins of the adjacently arranged heat exchange tubes, limiting the back mixing of the reaction materials with different residence times in the axial direction of the reactor, so that the uniformity of the composition distribution of the liquid reaction materials in the radial direction is significantly improved, thereby significantly improving the conversion rate, kinetics and selectivity of the reaction; in addition, the spiral fins on the outer wall of the heat exchange tube also provide a transfer rate of the reaction heat through the heat exchange tube.
  • the liquid reaction materials react on the surface of the catalyst particles loaded between the heat exchange tubes, and under the combined action of the left-handed and right-handed outer wall spiral fins of the adjacently arranged heat exchange tubes and the catalyst particles, the liquid reaction materials are further evenly mixed in the radial direction, so that the temperature is more evenly distributed in the radial direction, and then the composition of the reaction materials is more evenly distributed in the radial direction, thereby significantly improving the reaction kinetics and improving the reaction selectivity.
  • the spiral fin of the heat exchange tube is a multi-start thread with a number of thread starts n (n is a positive integer greater than 1)
  • n is a positive integer greater than 1
  • the pitch of the multi-start thread is the same as the pitch of the single-start thread, while achieving the above technical effects, due to the helical lead angle of the multi-start thread fin Approximately the helix angle of a single-start thread Therefore, the multi-threaded fins can better guide the fluid in the axial direction of the heat exchange tube and significantly reduce the pressure drop of the reactor.
  • the liquid distribution device includes a solid particle filling unit, the specifications and dimensions of each heat exchange tube are the same and are evenly arranged, the inlet and outlet ends of two adjacent U-shaped heat exchange tubes or the inlet ends of four adjacent straight heat exchange tubes are arranged in a square, the side length of the square is W, and the diameter of the heat exchange tube is D (see Figure 5), the cross-section of the spiral fin on the outer wall of the heat exchange tube is a triangle, half of the length of the base of the triangle is h, half of the vertex angle is ⁇ , the pitch of the spiral fin is H and the diameter of the heat exchange tube is D, the fixed bed height is l, and the number average diameter of the solid particles is d; then the structural parameters of the spiral fins, the structural parameters of the heat exchange tube arrangement, the reactor heat transfer coefficient and the reactor pressure drop respectively satisfy the following relations (1) and (2):
  • the characteristic size De (m) is defined as: Re Reynolds coefficient Pr (Prandtl number) represents the physical property constant.
  • ⁇ represents the heat transfer coefficient of the reactor (W/(m 2 ⁇ K));
  • ⁇ represents the density of the reaction liquid (kg/m 3 ),
  • ⁇ represents the viscosity of the reaction liquid (Pa ⁇ s);
  • u represents the flow rate of the reaction liquid (m/s), which is calculated as follows: Set the space velocity, such as 1.1h -1 , when the volume of catalyst loaded in the reaction tube is determined, the total feed volume flow rate can be determined, and the feed volume flow rate of a single repeating unit is calculated according to the number of repeating units in the catalyst loading area of Figure 5 in the reactor, and then divide the feed volume flow rate of a single repeating unit by the cross-sectional area of a single repeating unit.
  • W and D are shown in Figure 5, respectively, when the heat exchange tubes are arranged in a square, W is the side length of the square (m), and D is the diameter of the heat exchange tube (m); H and h respectively represent the pitch of the triangular spiral fin (m) and half of the length of the bottom side of the cross section of the triangular spiral fin (m); ⁇ is half of the vertex angle of the triangular spiral fin (in radians); c p represents the constant-pressure specific heat capacity of the liquid (J/(kg ⁇ °C)), ⁇ represents the thermal conductivity of the liquid (W/(m ⁇ K)); M and N are dimensionless constants, where M is related to the rotation direction of the rotating fins on the inner and outer walls of
  • the hot spot temperature rise of the reactor can be effectively controlled by a sufficiently high heat transfer coefficient ⁇ .
  • the reactor of the present invention is more suitable for a liquid-solid reaction system with a low space velocity, according to one embodiment, in formula (1), 0.6 ⁇ Re ⁇ 50, preferably 1 ⁇ Re ⁇ 35, and more preferably 2 ⁇ Re ⁇ 10.
  • ⁇ P represents the reactor pressure drop (Pa)
  • n is the number of thread heads (dimensionless)
  • d is the number average diameter of the catalyst particles (m)
  • l represents the height of the fixed bed (m)
  • the fixed values of other parameters are The meaning is the same as that of the above formula (1).
  • the low reactor pressure drop can reduce energy consumption.
  • ⁇ P ⁇ 2000 kPa preferably ⁇ P ⁇ 1000 kPa, more preferably ⁇ P ⁇ 600 kPa, more preferably ⁇ P ⁇ 300 kPa, and even more preferably ⁇ P ⁇ 150 kPa.
  • the above formula is particularly suitable for the case where the liquid in the reactor of the present invention is in a laminar flow state, wherein when 0.6 ⁇ Re ⁇ 50, and 1 ⁇ Pr ⁇ 3, the calculation error is within plus or minus 15%, and even most of them are within plus or minus 10%. Since Pr decreases with increasing temperature, Pr meets this requirement for the liquid in the reactor of the present invention (temperature greater than 80°C).
  • the present invention further provides a method for improving the temperature distribution of a fixed bed reactor, wherein the liquid distribution device of the present invention is used in the fixed bed reactor.
  • the present invention also provides a method for reducing the pressure drop of a fixed bed reactor, wherein the liquid distribution device of the present invention is used in the fixed bed reactor, wherein the liquid distribution device comprises a heat exchange tube having an outer wall spiral fin in the form of a multi-start thread.
  • FIG. 1 is a schematic structural diagram of a reactor according to an embodiment of the present invention.
  • FIG. 2 is a schematic diagram of the assembly structure of a liquid distribution device according to an embodiment of the present invention (the spiral fins are not shown).
  • FIG3 is a schematic diagram of a heat exchange tube with outer wall spiral fins according to the present invention and a partial enlarged view of the spiral fins.
  • FIG. 4 is a schematic cross-sectional view of a heat exchange tube with outer wall spiral fins according to the present invention (the cross-sectional shape of the spiral fins is an isosceles triangle).
  • FIG. 5 is a schematic diagram of the arrangement positions of heat exchange tubes and the catalyst loading area according to the present invention.
  • FIG. 6 is a schematic structural diagram of a liquid reaction material distributor according to the present invention.
  • FIG. 7 is a schematic diagram of the partial structure of left-handed and right-handed outer wall spiral fins of two adjacently arranged heat exchange tubes according to the present invention.
  • FIG. 8 is a schematic cross-sectional view of a heat exchange tube with spiral fins on the outer and inner walls according to the present invention (the cross-sectional shape of the spiral fins is an isosceles triangle).
  • FIG. 9 is a schematic diagram showing that the outer wall spiral fins and the inner wall spiral fins of the heat exchange tube rotate in opposite directions, wherein the outer wall spiral fins (indicated by solid lines) are right-handed and the inner wall spiral fins (indicated by dotted lines) are left-handed.
  • Figure 10 is a schematic diagram showing that the outer wall spiral fins and the inner wall spiral fins of the heat exchange tube have the same rotation direction, wherein the outer wall spiral fins (indicated by solid lines) are right-handed and the inner wall spiral fins (indicated by dotted lines) are right-handed.
  • FIG. 11 is a diagram showing the flow effect of the reaction fluid when all heat exchange tubes having right-handed outer wall spiral fins are arranged.
  • FIG. 12 is a diagram showing the flow effect of the reaction fluid when the heat exchange tubes with left-handed outer wall spiral fins and the heat exchange tubes with right-handed outer wall spiral fins are alternately arranged in an axially asymmetric manner.
  • FIG. 13 is a diagram showing the flow effect of the reaction fluid when the heat exchange tubes with left-handed outer wall spiral fins and the heat exchange tubes with right-handed outer wall spiral fins are alternately arranged in an axially symmetrical manner.
  • Figure 14 is a schematic diagram of the structure of the spiral fins on the outer wall of the heat exchange tube, which are single-start threads and multi-start threads respectively.
  • the right figure shows a single-start thread with a pitch of 3H
  • the left figure shows a single-start thread with a pitch of H
  • any specific numerical value (including the endpoint of the numerical range) disclosed in this specification is not limited to the exact value of the numerical value, but should be understood to also cover values close to the exact value, such as all possible values within the range of ⁇ 5% of the exact value.
  • the endpoint values of the range, the endpoint values and the specific point values in the range, and the specific point values can be arbitrarily combined to obtain one or more new numerical ranges, and these new numerical ranges should also be regarded as specifically disclosed in this specification.
  • the present invention relates to a reactor comprising a liquid distribution device, in particular a fixed bed reactor, wherein the liquid distribution device comprises:
  • a heat exchange tube unit comprising a plurality of vertically arranged heat exchange tubes, wherein at least a portion, preferably all of the heat exchange tubes are provided with left-handed or right-handed spiral fins on their outer walls, wherein the spiral fins on the outer walls of at least a portion of the heat exchange tubes rotate in opposite directions to the spiral fins on the outer walls of the adjacently arranged heat exchange tubes (in other words, the spiral fins on the outer walls of at least a portion of the adjacently arranged heat exchange tubes rotate in alternating directions of left-handed and right-handed rotations), and more preferably, the spiral fins on the outer walls of all the heat exchange tubes rotate in opposite directions to the spiral fins on the outer walls of the adjacently arranged heat exchange tubes (in other words, The spiral fins on the outer wall of all adjacently arranged heat exchange tubes are left-handed and right-handed alternately); the heat exchange medium flows in the heat exchange tubes, while the liquid reaction material flows outside the heat exchange tubes in a direction almost parallel to the axial direction of the heat exchange tubes;
  • An optional solid particle packing unit includes solid particles filled in the spaces between the heat exchange tubes.
  • the reactor is preferably a fixed bed reactor for a liquid-solid reaction system
  • the solid bed can be a solid filler bed or a solid catalyst bed, which includes fillers or solid catalysts in granular form filled in the space outside any heat exchange tube.
  • the heat exchange tube unit includes a plurality of vertically arranged heat exchange tubes, and the heat exchange tubes are selected from straight tube heat exchange tubes or U-shaped heat exchange tubes, preferably U-shaped heat exchange tubes; left-handed or right-handed spiral fins are provided on the outer wall of each heat exchange tube, wherein the outer wall spiral fins of at least a part of the heat exchange tubes rotate in opposite directions to the outer wall spiral fins of the adjacent heat exchange tubes (in other words, the outer wall spiral fins of at least a part of the adjacent heat exchange tubes rotate in opposite directions to the outer wall spiral fins of the adjacent heat exchange tubes (in other words, the outer wall spiral fins of all the adjacent heat exchange tubes rotate in opposite directions to the outer wall spiral fins of the adjacent heat exchange tubes (in other words, the outer wall spiral fins of all the adjacent heat exchange tubes rotate in alternation to the left and right).
  • the rotation directions of the outer wall spiral fins of the straight tube part of the U-shaped heat exchange tube can be the same or different from each other.
  • a U-shaped heat exchange tube with outer wall spiral fins is equivalent to two straight heat exchange tubes with outer wall spiral fins with the same or opposite rotation directions.
  • adjacently arranged heat exchange tubes refers to two heat exchange tubes arranged in this way: if the distance between their axial centers is smaller than the distance between their axial centers and other heat exchange tubes, then the two heat exchange tubes are adjacently arranged; if the distance between the axial center of a heat exchange tube and the axial centers of multiple heat exchange tubes is the same and the smallest, then the heat exchange tube is adjacently arranged to the multiple heat exchange tubes at the same time.
  • the ratio H/D is 0.2-1.7, preferably 0.3-1.3, for example 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1 and 1.2, wherein the above H and D are measured in the same length unit.
  • each heat exchange tube has the same specification and size and is evenly arranged in the liquid distribution device.
  • the diameter D and wall thickness of the heat exchange tube can be determined by those skilled in the art according to actual needs and based on their basic knowledge.
  • the diameter D can generally be 7-35 mm; preferably 10-25 mm, and the wall thickness can be about 1 mm.
  • the liquid reaction material flows from top to bottom outside the heat exchange tube, and the overall flow direction is preferably substantially parallel to the axis of the heat exchange tube.
  • the inventors were also surprised to find that in the liquid distribution device of the present invention, the combination of the structural features of solid particles, such as catalyst particles (especially particle sphericity and number average diameter) and the structural features of the spiral fins on the outer wall of the heat exchange tube has a synergistic effect on further improving the performance of the reactor of the present invention, making the fixed bed reactor of the present invention very suitable for liquid-solid catalytic reactions.
  • the catalyst bed contains nearly spherical solid catalyst particles with substantially equal particle sizes, having a sphericity greater than 0.8, preferably greater than 0.85, and more preferably greater than 0.9.
  • Sphericity is measured according to the surface area method well known in the art.
  • the number average diameter of the particles of the solid catalyst is d, so that d/W is 0.01-0.2, preferably 0.02-0.1, wherein the above W and d are measured in the same length unit.
  • the heat exchange tube is a U-shaped heat exchange tube, wherein the inlet and outlet ends of each U-shaped heat exchange tube are located on the same side and are spaced apart, preferably, located on the upper end side of the reactor. Support plates are provided at both the upper and lower ends of the heat exchange tube to keep the heat exchange tube upright.
  • spiral fins are provided on the inner wall of at least a portion, preferably all, of the heat exchange tubes, and the rotation directions of the spiral fins on the outer wall of the heat exchange tubes and the spiral fins on the inner wall of the heat exchange tubes can be the same or opposite, preferably opposite.
  • the spiral fin is a raised structure on the outer wall and/or inner wall of the heat exchange tube, wherein the cross-sectional shape of the raised structure is a triangle, a semicircle, a semi-ellipse or a rectangle.
  • the cross-sectional shape of the raised structure is a triangle, it is preferably a nearly isosceles triangle, and more preferably an isosceles triangle.
  • the term "nearly isosceles triangle" means that the length of the two sides of the cross-section of the spiral fin raised from the outer wall and/or the inner wall differs by less than 10%, preferably less than 5%, and more preferably are equal.
  • the cross-sectional shape of the protruding structure is a triangle
  • half of the length of the base of the triangle is h
  • half of the vertex angle is ⁇
  • the ratio h/D is 0.03-0.1, preferably 0.05-0.09
  • ⁇ is 10° to 60°, preferably 20° to 50°, for example 25°, 30°, 35°, 40° or 45°, wherein the above degrees and radians of the angle ⁇ can be converted to each other.
  • the rotation direction of the outer wall spiral fins and the rotation direction of the inner wall spiral fins of the heat exchange tube can be the same or opposite, preferably opposite.
  • the outer wall spiral fins of all heat exchange tubes have the same pitch H and the same cross-sectional shape; the inner wall spiral fins of all heat exchange tubes have the same pitch H and the same cross-sectional shape.
  • the pitch H of the outer wall spiral fins and the pitch H' of the inner wall spiral fins of the heat exchange tube can be the same or different.
  • the inventors have found that it is particularly advantageous when the pitch H' of the inner wall spiral fins of the heat exchange tube is 1-5 times, preferably 2-3 times, the pitch H of the outer wall spiral fins, because this makes it possible to significantly simplify the manufacturing process of the inner wall spiral fins and save manufacturing costs without affecting, or even more conducive to, the heat transfer efficiency of the heat exchange tube, the uniform distribution of temperature, and the uniform distribution of the liquid reaction material outside the heat exchange tube.
  • the outer wall spiral fins of the heat exchange tube are advantageously axially displaced from the inner wall spiral fins of the heat exchange tube by at least 1/4 of the pitch, preferably 1/2 of the pitch; or if the rotation direction of the outer wall spiral fins of the heat exchange tube is opposite to the rotation direction of the inner wall spiral fins of the heat exchange tube and the pitch H of the outer wall spiral fins of the heat exchange tube is the same as the pitch H' of the inner wall spiral fins of the heat exchange tube, then the outer wall spiral fins of the heat exchange tube are advantageously axially displaced from the inner wall spiral fins of the heat exchange tube by at most 1/4 of the pitch, preferably there is no dislocation.
  • the outer wall spiral fins of the heat exchange tube when the H/D of the outer wall spiral fins of the heat exchange tube is a certain value, the outer wall spiral fins can be in a single-start thread form or a multi-start thread form.
  • the number of thread heads n of the outer wall spiral fins of the heat exchange tube is 1, 2, 3 or 4, preferably 3 or 4.
  • the liquid distribution device also includes a liquid distributor, which is located above the heat exchange tube unit, and the porosity of the liquid outlet holes of the liquid distributor is 2 ⁇ -75 ⁇ , preferably 10 ⁇ -60 ⁇ , for example 20 ⁇ , 30 ⁇ , 40 ⁇ , 50 ⁇ .
  • the left-handed and right-handed outer wall spiral fins of any pair of adjacently arranged heat exchange tubes are axially misaligned by at most 1/3 of the pitch, preferably at most 1/4 of the pitch. More preferably, the left-handed and right-handed outer wall spiral fins of any pair of adjacently arranged heat exchange tubes are not axially misaligned, that is, they are distributed in mirror symmetry with respect to the axial direction.
  • the upper and lower ends of the solid particle filling unit are provided with
  • the lower end of the screen is arranged below the bottom of the heat exchange tube, so as to prevent the catalyst particles from leaking out from the gap between the screen and the heat exchange tube with outer wall rotating fins.
  • the upper end of the screen is arranged below the liquid distributor.
  • the heat exchange medium inlet manifold and/or the heat exchange medium outlet manifold of the reactor are located at the top of the reactor, and are arranged at a position higher than the liquid distributor.
  • the reactor of the present invention is a multiphase catalytic reactor, which is used for catalytic hydration reaction to prepare ethylene glycol, catalytic reaction to prepare diethylene glycol, catalytic reaction to prepare triethylene glycol, catalytic reaction to prepare propylene glycol, or catalytic reaction to prepare butanediol, wherein the liquid reaction materials are liquid ethylene oxide and liquid water, liquid ethylene oxide and liquid ethylene glycol, liquid ethylene oxide and liquid diethylene glycol, liquid propylene oxide and liquid water, or liquid butylene oxide and liquid water; and the solid catalyst used is selected from resins.
  • the present invention also relates to a method for carrying out a heterogeneous catalytic reaction, characterized in that a reactor as described above is used, in particular a fixed bed reactor.
  • the method is used to prepare ethylene glycol by catalytic hydration reaction of ethylene oxide, prepare diethylene glycol by catalytic reaction of ethylene oxide and ethylene glycol, prepare triethylene glycol by catalytic reaction of ethylene oxide and diethylene glycol, prepare propylene glycol by catalytic hydration reaction of propylene oxide, or prepare butylene glycol by catalytic hydration reaction of butylene oxide, etc., wherein the liquid reaction materials are liquid ethylene oxide and liquid water, liquid ethylene oxide and liquid ethylene glycol, liquid ethylene oxide and liquid diethylene glycol, liquid propylene oxide and liquid water, or liquid butylene oxide and liquid water; and the solid catalyst used is selected from resin.
  • the method is used to prepare ethylene glycol by catalytic hydration reaction of ethylene oxide, wherein the liquid reaction materials are liquid ethylene oxide and liquid water, and the solid catalyst used is a resin.
  • the method is used to prepare ethylene glycol by catalytic hydration reaction of ethylene oxide, wherein the liquid reaction materials are liquid ethylene oxide and liquid water, and the molar content ratio of liquid water to liquid ethylene oxide is less than or equal to 10:1, preferably less than or equal to 6:1, for example, 5:1, 4:1, 3:1.
  • liquid ethylene oxide and liquid water flow through a fixed bed reactor, contact with a solid catalyst bed loaded on the outside of the heat exchange tube and react to produce ethylene glycol, wherein the reaction temperature is 85-150°C, preferably 90-140°C, the pressure is 1.0-1.8 MPa, preferably 1.1-1.7 MPa, such as 1.2 MPa, 1.4 MPa, 1.6 MPa, and the liquid hourly space velocity is 0.5-5 h -1 , preferably 1-4 h -1 , such as 2 h -1 , 3 h -1 .
  • heat exchange tubes with outer wall spiral fins are generally used in heat exchangers, and usually adopt an arrangement mode in which all outer wall spiral fins are right-handed or left-handed as shown in FIG11.
  • the inventors have found through research that the heat exchange tubes with outer wall spiral fins are used in fixed bed reactors, and the reaction fluid material flows outside the heat exchange tubes in a direction parallel to the axial direction of the heat exchange tubes, which can significantly improve the reaction kinetics of the reaction fluid, control its reaction rate, and significantly improve its reaction yield and selectivity while effectively transferring heat.
  • the inventors also found that, as shown in FIG12, when the heat exchange tubes with left-handed outer wall spiral fins and the heat exchange tubes with right-handed outer wall spiral fins are arranged alternately adjacent to each other in the heat exchange tube unit, but the outer wall spiral fins of the two heat exchange tubes are misaligned by more than one-third of the pitch in the axial direction, although the reaction fluid produces a flow effect of alternating divergence and convergence in the radial direction of the reactor, stream a and stream b still have different flow paths, and the two have different residence times in the reactor, and a back-mixing effect will occur when they converge.
  • the flow effect of the reaction fluid is shown in FIG12.
  • the pitch of the spiral fins on the outer wall of the heat exchange tube unit also has a significant effect on the heat transfer capacity.
  • the smaller the pitch H the better the heat transfer capacity of the heat exchange tube unit, the smaller the hot spot temperature rise of the reactor, the higher the reaction selectivity, and the better the reaction performance.
  • the smaller the single-start thread H the higher the helix angle of the thread. As the fluid passes through the threads, it exchanges heat. The resistance encountered in the axial direction of the tube will become larger, which will cause excessive pressure drop in the entire reactor.
  • the pitch H is the same as that of single-start threads, while ensuring the same or even better heat transfer effect, it can also significantly reduce the pressure drop of the reactor, optimize the flow state of the fluid on the spiral fins on the outer wall of the heat exchange tube, and improve the reaction performance of the reactor.
  • the pitch of the right figure is larger, and the heat transfer capacity is poor.
  • the pitch of the middle figure is 1/3 of the pitch of the right figure, and the heat transfer capacity is enhanced, but the helix angle of the thread in the middle figure is Approximately the spiral angle of the left figure It is three times the diameter of the reactor, which promotes the flow of fluid in the axial direction and significantly reduces the pressure drop of the reactor.
  • the liquid distribution device is particularly suitable for fixed bed reactors, and is especially suitable for fixed bed reactors for liquid-solid multiphase catalytic reactions with low liquid hourly space velocity.
  • the liquid distribution device includes a plurality of U-shaped heat exchange tubes of the same specification and size arranged vertically and evenly, so that the inlet and outlet ends of the U-shaped heat exchange tubes are arranged in a square interval; the heat exchange medium flows in the U-shaped heat exchange tubes and solid catalyst particles are filled on the outside of the U-shaped heat exchange tubes to form a catalyst bed; the liquid reaction material enters the space where the solid catalyst particle bed is located evenly from top to bottom and performs a catalytic reaction under the temperature control of the heat exchange medium; during the reaction process, the spiral fins on the outer wall of the U-shaped heat exchange tube can prevent the liquid reaction material from flowing along the outer wall of the U-shaped heat exchange tube, and maintain the uniform distribution of the liquid reaction material in the solid catalyst bed.
  • the outer wall spiral fins of the heat exchange tube rotate in opposite directions to the inner wall spiral fins, so that the uniformity of the heat transfer between the outer wall and the inner wall of the heat exchange tube can be improved, and the heat transfer resistance and thermal stress can be reduced; further, the uniform distribution of the local temperature of the outer wall of the heat exchange tube can promote the uniform distribution of the composition of the reaction fluid.
  • the heat exchange tubes with left-handed outer wall spiral fins and the heat exchange tubes with right-handed outer wall spiral fins are arranged alternately adjacent to each other, which can significantly improve the uniformity of the composition and temperature distribution of the reaction fluid, thereby improving the performance of the reactor.
  • the outer wall spiral fins of the adjacent alternately arranged heat exchange tubes are distributed in mirror symmetry in the axial direction.
  • the converging fluids have the same residence time due to the flow channels with mirror symmetry, thereby avoiding the back-mixing effect of fluids with different residence times when converging.
  • the reactor according to the present invention has the following beneficial effects:
  • the liquid material flowing along the outer wall of the heat exchange tube can be effectively guided to flow in the radial direction, avoiding the axial channel flow of the liquid material on the outer wall, so that the distribution of the fluid in the catalyst particle loading area is more uniform; at the same time, it can also effectively reduce the thickness of the liquid film on the outer wall of the heat exchange tube, reduce the heat transfer resistance, and effectively improve the heat transfer capacity;
  • the spiral fin structure can guide the liquid reaction material to flow radially as long as it protrudes from the outer wall of the heat exchange tube, but when the cross-section of the spiral fin is an isosceles triangle, the effect of guiding the fluid is better; the inventors further found that the effect of guiding the fluid is closely related to indicators such as the base and vertex angle of the isosceles triangle; the specific value range of the ratio h/D of the base h of the isosceles triangle relative to the dimension D of the heat exchange tube diameter and the specific angle range of the vertex ⁇ used in the present invention can not only effectively avoid the channel flow phenomenon on the outer wall of the heat exchange tube, improve the mass transfer and heat transfer capacity of the catalytic reaction, but also will not generate excessive resistance to the fluid flow through the catalyst bed, thereby reducing the pressure drop of the reactor;
  • the inventors After research, the inventors also found that if spiral fins are arranged on the inner wall of the heat exchange tube, so that the position of the inner wall spiral fins does not overlap with the position of the outer wall spiral fins, and the outer wall spiral fins of the heat exchange tube rotate in opposite directions to the inner wall spiral fins, the areas covered by the inner wall and outer wall spiral fins can be made more symmetrical.
  • the area formed by the spiral fins and the outer wall of the heat exchange tube in this arrangement is symmetrically distributed about the central axis of the heat exchange tube.
  • This symmetry effectively improves the uniformity of the spiral fins to enhance the heat transfer between the outer wall and the inner wall of the heat exchange tube, avoids excessive local temperature difference between the outer wall and the inner wall of the heat exchange tube, reduces thermal stress, and reduces the adverse effects of deformation caused by thermal stress on the service life of the heat exchange tube.
  • the uniform distribution of the local temperature of the outer wall of the heat exchange tube can promote the uniform distribution of the reaction fluid.
  • the inventors also found that in the heat exchange tube unit, the heat exchange tubes with left-handed outer wall spiral fins and the heat exchange tubes with right-handed outer wall spiral fins are arranged alternately adjacent to each other.
  • This arrangement makes the heat exchange tubes symmetrical in the vertical direction.
  • This symmetrical structure can guide the flow direction of the reaction fluid. Since the rotation directions of the outer wall spiral fins of adjacent heat exchange tubes are opposite, the liquid material produces a flow effect of alternating diversion and convergence in the radial direction of the reactor, avoiding the liquid material from deviating in a single direction, thereby making the fluid more evenly distributed in the catalyst particle loading area.
  • the spiral fins also have a guiding effect on the forward flow of the fluid, which can effectively reduce axial liquid backmixing.
  • the inventors After research, the inventors also found that the adjacent alternatingly arranged heat exchange tubes with left-handed or right-handed outer wall spiral fins are distributed in a mirror-symmetrical manner in the axial direction, and the converging fluids flow through flow channels with a mirror-symmetrical relationship, so they have the same residence time, so there is no back-mixing effect when fluids with different residence times converge.
  • each U-shaped heat exchange tube is arranged on the same side and evenly spaced. Since each heat exchange tube adopts the same size specification, the overall structure of the liquid distribution device is more reasonable and the radial temperature difference in the reactor is controlled to a smaller value.
  • the present invention can effectively improve the reaction uniformity in the radial direction of the reactor, and avoid the additional thermal stress caused by the large radial temperature difference causing the reactor to produce thermal deformation, thereby increasing the service life of the reactor;
  • the present invention sets the screen at the lower end of the catalyst bed below the bottom of the heat exchange tube, which can effectively Reduce the risk of catalyst leakage caused by the heat exchange tube passing through the screen, and reduce the difficulty of reactor manufacturing and processing;
  • the present invention proposes a dimensionless numerical correlation formula for calculating the heat transfer and pressure drop of a reactor with spiral fins, and the calculation error meets the requirements for engineering use.
  • the present invention is particularly suitable for use in fixed-bed reactors for multiphase catalytic reactions, i.e., scenarios in which the reaction materials are all in liquid phase and the catalyst is solid catalyst particles; it is particularly suitable for use in processes such as preparing ethylene glycol by catalytic hydration of ethylene oxide, preparing diethylene glycol by catalytic reaction of ethylene oxide and ethylene glycol, preparing triethylene glycol by catalytic reaction of ethylene oxide and diethylene glycol, preparing propylene glycol by catalytic hydration of propylene oxide, preparing butanediol by catalytic hydration of butylene oxide, etc.
  • spatial relative terms such as “below”, “below”, “down”, “above”, “above”, “upper”, etc. may be used to describe the relationship between one element or feature and another element or feature in the drawings. It should be understood that the spatial relative terms are intended to include different orientations of the object in use or operation in addition to the orientation depicted in the figure. For example, if the object in the figure is turned over, the element described as being “below” or “below” other elements or features will be oriented “above” the element or feature. Therefore, the exemplary term “below” can include both the below and above directions. Objects may also have other orientations (rotated 90 degrees or other orientations) and the spatial relative terms used in this specification should be interpreted accordingly.
  • the present invention provides an embodiment of a liquid distribution device in which the heat exchange tube is a U-shaped heat exchange tube, which is mainly used in a multiphase catalytic reaction system, and is particularly suitable for catalytic reactions of liquid materials under the action of a solid catalyst bed and at a relatively mild reaction temperature (e.g., about 100°C), such as the multiphase catalytic hydration of ethylene oxide to prepare ethylene glycol, the catalytic reaction of ethylene oxide and ethylene glycol to prepare diethylene glycol, the catalytic reaction of ethylene oxide and diethylene glycol to prepare triethylene glycol, the multiphase catalytic hydration reaction of propylene oxide to prepare propylene glycol, or the multiphase catalytic hydration reaction of butylene oxide to prepare butanediol.
  • a relatively mild reaction temperature e.g., about 100°C
  • reaction temperature is controlled by introducing a heat exchange medium (cooling or heating) into the heat exchange tubes of the heat exchange tube unit.
  • the upper and lower ends of the U-shaped heat exchange tube 1 of the present invention are provided with support plates, namely, the upper support plate 11 of the heat exchange tube and the lower support plate 12 of the heat exchange tube.
  • the array formed by the heat exchange tube 1 can be firmly installed in the effective space of the reactor.
  • Screens can be provided at both the upper and lower ends of the catalyst bed, namely, the catalyst top screen 31 and the catalyst bottom screen 32 in FIG1 . In this way, the filled catalyst particles can be confined to the effective area between the heat exchange tubes 1.
  • the catalyst bottom screen 32 is arranged below the bottom of the heat exchange tube 1.
  • the catalytic reaction liquid material of the present invention enters from the top of the reactor, there is no leakage problem of the top screen of the reactor.
  • the bottom of the U-shaped heat exchange tube 1 is arranged above the bottom screen 32, that is, it does not pass through the catalyst screen, which can effectively reduce the risk of catalyst leakage caused by the U-shaped heat exchange tube passing through the screen, and reduce the difficulty of reactor manufacturing and processing.
  • the liquid distribution device of the present invention includes: a heat exchange tube unit and a catalyst bed.
  • the heat exchange tubes in the heat exchange tube unit are U-shaped heat exchange tubes, and there are multiple of them, and they are arranged vertically.
  • the inlet end (i.e., the heat exchange medium inlet 1A in Figure 2) and the outlet end (i.e., the heat exchange medium outlet 1B in Figure 2) of each U-shaped heat exchange tube 1 are located on the same side and are arranged at intervals.
  • the inlet end and the outlet end are located on the same side means that heat exchange tubes of the same specifications are arranged regularly, so that an inlet-outlet-inlet-outlet arrangement can be formed, so that the overall structure of the liquid distribution device is more reasonable and the radial temperature difference in the reactor is controlled to a smaller value.
  • the present invention can effectively improve the uniformity of the reaction on the radial cross section of the reactor, avoid the additional thermal stress caused by the radial temperature difference causing thermal deformation of the reactor, and improve the service life of the reactor.
  • the outer wall of the heat exchange tube is provided with a spiral fin 10 (refer to FIG3 ).
  • the spiral fin may be a raised structure on the outer wall of the heat exchange tube, and the cross-section of the raised structure may be a triangle, semicircle, semi-ellipse or rectangle.
  • the purpose of providing the spiral fin is not only to solve the problem of uneven fluid distribution in the catalyst particle loading area caused by the channel flow phenomenon of the liquid on the outer wall of the U-shaped tube in the prior art, but also to make the fluid flow along the radial direction of the reactor, thereby promoting the uniform distribution of the composition and temperature of the fluid in the radial direction.
  • a heat exchange medium is introduced into the heat exchange tube 1 to maintain and control the temperature required for the catalytic reaction.
  • the catalyst bed actually occupies the outer side of the heat exchange tube in the heat exchange tube unit.
  • a space (refer to the catalyst loading area 3 in FIG. 5 ), in which solid catalyst particles are filled; liquid reaction materials flow in the space to perform a catalytic reaction.
  • the present invention arranges spiral fins on the outer wall of the U-shaped heat exchange tube.
  • the liquid material flowing along the outer wall of the heat exchange tube can be effectively guided to flow in the radial direction, avoiding the channeling phenomenon, so that the distribution of the fluid in the catalyst particle loading area is more uniform.
  • the thickness of the liquid film on the outer wall of the heat exchange tube can be effectively reduced, the heat transfer resistance can be reduced, and the heat transfer capacity can be more effectively improved.
  • the cross section of the raised structure of the spiral fin 10 can be an isosceles triangle.
  • the spiral fin 10 can guide the liquid reaction material to flow radially as long as it protrudes from the outer wall of the heat exchange tube 1, but when the cross section of the spiral fin is an isosceles triangle, the effect of guiding the liquid is better.
  • the effect of guiding the liquid is also closely related to indicators such as the base and vertex angle of the isosceles triangle.
  • the ratio H/D is within the range of 0.2-1.7, preferably 0.3-1.3, such as 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1 and 1.2.
  • the ratio h/D is in the range of 0.03-0.1, preferably 0.05-0.09, such as 0.05, 0.06, 0.07 and 0.08, and ⁇ is in the range of 10° to 60°, preferably 20° to 50°, such as 20°, 25°, 30°, 35°, 40°, 45° or 50°.
  • the fin structure will be smoother, which will reduce the disturbance effect of the spiral fin on the liquid, making the role of guiding the flow in the radial direction limited, and the ability of the spiral fin to reduce the channel flow phenomenon on the outer wall of the heat exchange tube and enhance the heat transfer will be reduced.
  • ⁇ is too small, the structure of the spiral fin is too sharp, which is equivalent to adding a raised obstacle in front of the fluid, which will produce greater resistance to the axial flow of the fluid, causing the fluid to have a thicker surface above and below the spiral fin. Stagnation layer will also reduce the ability of the spiral fin to enhance mass transfer.
  • the use of spiral fins with the above dimensions can further optimize the above technical effects.
  • two adjacent U-shaped heat exchange tubes are closely arranged (refer to the left side of Figure 5), the inlet ends and outlet ends of the two heat exchange tubes can be arranged in a square, and the rotation directions of the spiral fins on the outer walls of two adjacent heat exchange tubes are opposite; when the side length of the square is W and the diameter of the heat exchange tube is D, the ratio W/D is 1.2-3, preferably 1.5-2.5, preferably 1.8-2.4, for example 1.8, 1.9, 2.0, 2.1, 2.2 and 2.3.
  • the inventors also found that the larger the distance between the axial centers of the two U-shaped heat exchange tubes 1 (that is, the side length W of the square), the larger the space for loading the catalyst, and the greater the reactor production capacity, but the heat transfer area corresponding to the unit volume of catalyst will decrease, and the smaller W, the smaller the space for loading the catalyst, and the reactor production capacity will decrease, but the heat transfer area corresponding to the unit volume of catalyst will increase, which helps to remove the heat generated in the reaction, avoid excessive temperature rise, reduce the occurrence of side reactions, and also improve the intrinsic safety characteristics of the reactor.
  • the present invention adopts a square arrangement, and makes the ratio of the side length W of the square to the diameter D of the heat exchange tube within the above range.
  • the square arrangement can further improve the flow uniformity of the liquid reaction material in the catalyst loading area, and can effectively reduce the hot spot temperature rise of the reactor. Moreover, due to the use of a specific liquid distribution device in the reactor of the present invention, the production capacity of the reactor of the present invention is significantly improved.
  • spiral fins are also provided on the inner wall of the heat exchange tube.
  • the outer wall spiral fins of the heat exchange tube rotate in opposite directions to the inner wall spiral fins.
  • This symmetry can effectively improve the uniformity of the enhanced heat transfer of the spiral fins to the outer wall and the inner wall of the heat exchange tube, avoid excessive local temperature difference between the outer wall and the inner wall of the heat exchange tube, reduce thermal stress, and reduce the adverse effect of deformation caused by thermal stress on the service life of the heat exchange tube.
  • the uniform distribution of the local temperature of the outer wall of the heat exchange tube can promote the uniform distribution of the reaction fluid.
  • the area formed by the spiral fins and the outer wall of the heat exchange tube is not symmetrical about the central axis of the heat exchange tube and does not have the advantages of the structure shown in FIG9 .
  • the heat exchange tubes with left-handed outer wall spiral fins and the heat exchange tubes with right-handed outer wall spiral fins are arranged alternately adjacent to each other, and the adjacent alternately arranged heat exchange tubes are distributed in a mirror-symmetrical manner in the axial direction.
  • This symmetrical structure can play a good role in the uniform distribution of the reaction fluid in the radial direction, and when the rotation directions of the outer wall spiral fins of the adjacently arranged heat exchange tubes are opposite, this can make the liquid material flowing through the spiral fins produce a flow effect of alternating diversion and convergence in the radial direction of the reactor. Avoid the liquid material from deviating in a single direction caused by the outer wall spiral fins of all heat exchange tubes having one rotation direction.
  • the number of thread heads n of the spiral fins on the outer wall of the heat exchange tube is greater than 1, and preferably the number of thread heads n is 2, 3 or 4.
  • the inventors have found through research that compared with single-start threads, spiral fins in the form of multiple-start threads have a larger helical lead angle at the same pitch H, have a better axial flow guide effect on the reaction fluid outside the heat exchange tube, and can significantly reduce the pressure drop of the reactor.
  • the liquid distribution device of the present invention is particularly suitable for multiphase catalytic reactions.
  • the multiphase catalytic reactor can be selected from a reactor for preparing ethylene glycol by catalytic hydration, a reactor for preparing diethylene glycol by catalytic reaction of ethylene oxide and ethylene glycol, a reactor for preparing triethylene glycol by catalytic reaction of ethylene oxide and diethylene glycol, a reactor for preparing propylene glycol by catalytic hydration, and a reactor for preparing butanediol by catalytic hydration;
  • the liquid reaction materials can be liquid ethylene oxide and liquid water, liquid ethylene oxide and liquid ethylene glycol, liquid ethylene oxide and liquid diethylene glycol, liquid propylene oxide and liquid water, or liquid butylene oxide and liquid water;
  • the solid catalyst used can be selected from resins.
  • the present invention also provides a fixed bed reactor (fixed bed is not shown), which includes the aforementioned liquid distribution device.
  • the heat exchange medium inlet manifold 13 and the heat exchange medium outlet manifold 14 of the fixed bed reactor are both located at the top of the reactor, and their arrangement positions are higher than the liquid distributor.
  • the heat exchange medium inlet 1A of all U-shaped heat exchange tubes is connected to the heat exchange medium inlet manifold 13, and the heat exchange medium outlet 1B of all U-shaped heat exchange tubes is connected to the heat exchange medium outlet manifold 14.
  • the liquid distributor 2 is located above the reactor, The flow direction of the reaction fluid is parallel to the axis of the reactor.
  • the liquid outlet 21 of the liquid distributor 2 is preferably arranged in the middle area above the solid particle loading unit, so as to ensure that the descending liquid material is as evenly distributed as possible in the catalyst loading area.
  • the opening rate of the distributor liquid outlet can be 2 ⁇ -75 ⁇ .
  • the present invention also provides a reaction method using the aforementioned fixed bed reactor, wherein the fixed bed reactor is suitable for carrying out multiphase catalytic reactions, and comprises a plurality of U-shaped heat exchange tubes of the same specifications and sizes which are evenly arranged vertically, wherein the inlet and outlet ends of the U-shaped heat exchange tubes are spaced apart; the inner wall and the outer wall of the U-shaped heat exchange tubes are both provided with spiral fins; a heat exchange medium is introduced into the U-shaped heat exchange tubes and solid catalyst particles are filled on the outer side of the U-shaped heat exchange tubes to form a solid catalyst bed; liquid reaction materials which evenly enter the solid catalyst bed from top to bottom carry out a catalytic reaction on the catalyst surface under the temperature control of the heat exchange medium; during the reaction process, the spiral fins on the outer wall of the U-shaped heat exchange tubes are used to prevent channeling on the outer wall to keep the liquid phase in the solid catalyst bed evenly distributed.
  • the fixed bed reactor is suitable for carrying out multiphase catalytic reactions, and comprises a plurality of U
  • the outer wall spiral fins and the inner wall spiral fins of the heat exchange tube rotate in opposite directions.
  • the area surrounded by the outer wall spiral fins and the outer wall of the heat exchange tube is symmetrical about the central axis of the heat exchange tube. This symmetry can effectively improve the uniformity of the spiral fins on the outer wall and the inner wall of the heat exchange tube, avoid excessive local temperature difference between the outer wall and the inner wall of the heat exchange tube, and reduce thermal stress.
  • the heat exchange tubes with left-handed outer wall spiral fins and the heat exchange tubes with right-handed outer wall spiral fins are distributed in a mirror-symmetrical manner in the axial direction, the liquid material flowing through the spiral fins produces a separation and convergence effect, thereby ensuring the uniform distribution of the liquid in the solid catalyst bed in the radial direction.
  • the spiral fins can guide the flow of the fluid to strengthen the flow of the liquid in the radial direction while reducing the back mixing in the axial direction. The above effects can improve the raw material conversion rate and reaction selectivity.
  • the reaction method can be used to prepare ethylene glycol by catalytic hydration reaction of ethylene oxide, prepare diethylene glycol by catalytic reaction of ethylene oxide and ethylene glycol, prepare triethylene glycol by catalytic reaction of ethylene oxide and diethylene glycol, prepare propylene glycol by catalytic hydration reaction of propylene oxide, prepare butanediol by catalytic hydration reaction of butylene oxide, etc.
  • liquid ethylene oxide and liquid water are used as liquid reaction materials, and the solid catalyst used is selected from resin; wherein under the conditions of reaction temperature of 85 to 150°C, pressure of 1.0 to 1.8 MPa, and space velocity of 0.5 to 5 h -1 , the liquid reaction material contacts and reacts with the solid catalyst loaded on the outside of the heat exchange tube in the fixed bed reactor of the present invention, and ethylene glycol is produced with high selectivity and high yield.
  • the raw material conversion rate is calculated by the change in the concentration of ethylene oxide at the reactor inlet and outlet; the concentration of ethylene oxide is measured by gas chromatography; the selectivity of ethylene glycol is calculated by the measured value of the concentration of ethylene glycol at the reactor outlet; and the hot spot temperature rise of the reactor is measured as follows: a sleeve is inserted into the catalyst bed at the center shown in Figure 5, and a thermocouple is inserted into the sleeve and moved up and down.
  • the maximum value of the hot spot temperature rise usually appears at the upper part of the catalyst bed, that is, the distance from the top surface of the catalyst bed to the hot spot is about 20% of the catalyst bed height; but the hot spot position will change with the process conditions such as liquid hourly space velocity and raw material ratio.
  • the reactor pressure drop is the difference between the inlet and outlet pressures of the reaction fluid, measured by a differential pressure gauge. The measurement of other parameters is carried out according to conventional methods in the art.
  • This embodiment uses a fixed bed reactor for preparing ethylene glycol by multiphase catalytic hydration as shown in FIG1 , the reactor diameter is 500 mm, the fixed bed height is 1300 mm; it contains a plurality of U-shaped heat exchange tubes, the diameter D of which is 15 mm and the wall thickness is 1 mm; wherein the outer wall of the U-shaped heat exchange tube is provided with a spiral fin whose cross section is an isosceles triangle, and the inner wall of the heat exchange tube is provided with a spiral fin whose cross section is an isosceles triangle, the outer wall spiral fin of a part of the heat exchange tube is left-handed, and the outer wall spiral fin of another part of the heat exchange tube is right-handed.
  • the inner wall spiral fin and the outer wall spiral fin of the same heat exchange tube have opposite rotation directions and equal pitches.
  • the heat exchange tube with left-handed outer wall spiral fin and the heat exchange tube with right-handed outer wall spiral fin are arranged alternately adjacent to each other, as shown in FIG13 , and two adjacent U-shaped heat exchange tubes are arranged in mirror symmetry.
  • the cross section of the outer spiral fin is the same as that of the inner spiral fin of the heat exchange tube, where the ratio of h to the diameter D of the U-shaped heat exchange tube is 0.08, and ⁇ is 30°.
  • the ratio of the pitch H to D is 0.5, and the corresponding helical angle is is 14°.
  • Every two U-shaped heat exchange tubes are arranged in a square manner, the ratio W/D of the distance W between the axial centers of two adjacent heat exchange tubes to the diameter D of the U-shaped heat exchange tube is 2, and the liquid distributor has an opening rate of 40 ⁇ .
  • the catalyst unit contains spherical resin catalyst particles, whose sphericity is 0.85 and whose number average diameter d makes the ratio d/D about 0.1.
  • the liquid reaction material is fed into the reactor at a liquid hourly space velocity of 1.1h -1 through a liquid distributor with an opening rate of 40 ⁇ , wherein the molar ratio of liquid water to liquid ethylene oxide is 5:1, and ethylene glycol is synthesized in the reactor by catalytic hydration reaction.
  • the raw material conversion rate is greater than 99.9%
  • the selectivity of ethylene glycol is greater than 99.9%
  • the hot spot temperature rise of the reactor is 3.5° C.
  • the pressure drop of the reactor is 165 kPa.
  • This example uses a fixed bed reactor similar to that of Example 1 and operating parameters similar to those of Example 1, but the difference is that ⁇ is 45°.
  • the liquid material is fed into the reactor at a liquid hourly space velocity of 1.1 h -1 through a liquid distributor with an opening rate of 40 ⁇ , wherein the molar ratio of liquid water to liquid ethylene oxide is 5:1, and ethylene glycol is synthesized in the reactor by catalytic hydration reaction.
  • the raw material conversion rate is greater than 99.9%
  • the selectivity of ethylene glycol is 99.7%
  • the hot spot temperature rise of the reactor is 3.7°C
  • the pressure drop of the reactor is 135 kPa.
  • This example uses a fixed bed reactor similar to that of Example 1 and operating parameters similar to those of Example 1, but the difference is that the ratio of h to the diameter D of the U-shaped heat exchange tube h/D is 0.04.
  • the liquid material is fed into the reactor at a liquid hourly space velocity of 1.1 h -1 through a liquid distributor with an opening rate of 40 ⁇ , wherein the molar ratio of liquid water to liquid ethylene oxide is 5:1, and ethylene glycol is synthesized in the reactor by catalytic hydration reaction.
  • the raw material conversion rate is greater than 99.9%
  • the selectivity of ethylene glycol is 99.5%
  • the hot spot temperature rise of the reactor is 3.8°C
  • the pressure drop of the reactor is 126 kPa.
  • This embodiment uses a fixed bed reactor similar to that of embodiment 1 and operating parameters similar to those of embodiment 1, but the difference is that the ratio W/D of the distance W between the centers of two adjacent heat exchange tubes and the diameter D of the U-shaped heat exchange tube is 2.5.
  • the liquid material is fed into the reactor at a liquid hourly space velocity of 1.1h -1 through a liquid distributor with an opening rate of 40 ⁇ , and the molar ratio of liquid water to liquid ethylene oxide is 5:1.
  • Ethylene glycol is synthesized in the reactor by catalytic hydration reaction.
  • the raw material conversion rate is greater than 99.9%
  • the selectivity of ethylene glycol is 99.0%
  • the hot spot temperature rise of the reactor is 4.2°C
  • the pressure drop of the reactor is 105kPa.
  • This example uses a fixed bed reactor similar to that of Example 1 and operating parameters similar to those of Example 1, but the difference is that the ratio of the pitch H to D is 1.
  • the liquid material is fed into the reactor at a liquid hourly space velocity of 1.1 h -1 through a liquid distributor with an opening ratio of 40 ⁇ .
  • the molar ratio of liquid water to liquid ethylene oxide is 5:1, and ethylene glycol is synthesized in the reactor by catalytic hydration reaction.
  • the raw material conversion rate is greater than 99.9%
  • the selectivity of ethylene glycol is 99.2%
  • the hot spot temperature rise of the reactor is 4.0°C
  • the pressure drop of the reactor is 80kPa.
  • This embodiment uses a fixed bed reactor similar to that of embodiment 1 and operating parameters similar to those of embodiment 1, but the difference is that the ratio H/D of the pitch H to D is 1 and the ratio W/D of the distance W between the centers of two adjacent heat exchange tubes and the diameter D of the U-shaped heat exchange tube is 1.7.
  • the liquid material is fed into the reactor at a liquid hourly space velocity of 1.1h -1 through a liquid distributor with an opening rate of 40 ⁇ , and the molar ratio of liquid water to liquid ethylene oxide is 5:1.
  • Ethylene glycol is synthesized in the reactor by catalytic hydration reaction.
  • the raw material conversion rate is greater than 99.9%
  • the selectivity of ethylene glycol is 99.8%
  • the hot spot temperature rise of the reactor is 3.6°C
  • the pressure drop of the reactor is 129kPa.
  • This embodiment uses a fixed bed reactor similar to that of embodiment 1 and operating parameters similar to those of embodiment 1, but the difference is that the ratio H/D of the pitch H to D is 1.5, the ratio W/D of the distance between the centers of two adjacent heat exchange tubes and the diameter D of the U-shaped heat exchange tube is 1.7, and ⁇ is 20°.
  • the liquid material is fed into the reactor at a liquid hourly space velocity of 1.1h -1 through a liquid distributor with an opening rate of 40 ⁇ , and the molar ratio of liquid water to liquid ethylene oxide is 5:1.
  • Ethylene glycol is synthesized in the reactor by catalytic hydration reaction.
  • the raw material conversion rate is greater than 99.9%
  • the selectivity of ethylene glycol is 99.2%
  • the hot spot temperature rise of the reactor is 4.1°C
  • the pressure drop of the reactor is 101kPa.
  • This embodiment uses a fixed bed reactor similar to that of embodiment 1 and operating parameters similar to those of embodiment 1, but the difference is that the ratio H/D of the pitch H to D is 1, the ratio W of the distance between the centers of two adjacent heat exchange tubes to the diameter D of the U-shaped heat exchange tube is 2.2, the ratio h/D of h to the diameter D of the U-shaped heat exchange tube is 0.1, and ⁇ is 20°.
  • the liquid material is fed into the reactor at a liquid hourly space velocity of 1.1h -1 through a liquid distributor with an opening rate of 40 ⁇ , and the molar ratio of liquid water to liquid ethylene oxide is 5:1.
  • Ethylene glycol is synthesized in the reactor by catalytic hydration reaction.
  • the raw material conversion rate is greater than 99.9%
  • the selectivity of ethylene glycol is 98.9%
  • the hot spot temperature rise of the reactor is 4.5°C
  • the pressure drop of the reactor is 83kPa.
  • This embodiment uses a fixed bed reactor similar to that of embodiment 1 and operating parameters similar to those of embodiment 1, but the difference is that the inner wall spiral fins and the outer wall spiral fins of the same heat exchange tube have the same rotation direction and equal pitch.
  • the liquid material is fed into the reactor at a liquid hourly space velocity of 1.1h -1 through a liquid distributor with an opening rate of 40 ⁇ , wherein the molar ratio of liquid water to liquid ethylene oxide is 5:1, and ethylene glycol is synthesized in the reactor by catalytic hydration reaction.
  • the raw material conversion rate is greater than 99.9%
  • the selectivity of ethylene glycol is 99.0%
  • the hot spot temperature rise of the reactor is 4.2°C
  • the pressure drop of the reactor is 167kPa.
  • Example 9 By comparing Example 9 with Example 1, it can be seen that since the rotation direction of the inner wall spiral fins of the heat exchange tubes included in the reactor used in Example 1 is opposite to the rotation direction of the outer wall spiral fins, the feedstock conversion rate and the selectivity of ethylene glycol of the reactor according to Example 1 are higher than the corresponding parameters of Example 9, and the hot spot temperature of the reactor of Example 1 is lower. This shows that the rotation direction of the inner wall spiral fins and the rotation direction of the outer wall spiral fins of the heat exchange tubes in the reactor have a synergistic effect on the performance of the reactor.
  • This comparative example uses a fixed bed reactor similar to that of Example 1 and operating parameters similar to those of Example 1, but the difference is that the rotation direction of the spiral fins on the outer wall of the straight tube part of all U-shaped heat exchange tubes is right-handed, and any two adjacent U-shaped heat exchange tubes are arranged as shown in Figure 11; the rotation direction of the spiral fins on the inner wall of the heat exchange tube is opposite to the rotation direction of the spiral fins on the outer wall of the heat exchange tube.
  • the liquid reaction material is fed into the reactor at a liquid hourly space velocity of 1.1h -1 through a liquid distributor with an opening rate of 40 ⁇ , and the molar ratio of liquid water to liquid ethylene oxide is 5:1.
  • Ethylene glycol is synthesized in the reactor by catalytic hydration reaction. After measurement, for the reaction of synthesizing ethylene glycol in the reactor, the raw material conversion rate is 98.2%, the selectivity of ethylene glycol is 98.3%, the hot spot temperature rise of the reactor is 4.9°C, and the pressure drop of the reactor is 162kPa.
  • This comparative example uses a fixed bed reactor similar to that of Example 1 and operating parameters similar to those of Example 1, but the difference is that the rotation direction of the spiral fins on the outer wall of the straight tube portion of the U-shaped heat exchange tube is all left-handed, and two adjacent U-shaped heat exchange tubes are arranged as shown in FIG11. The rotation direction of the spiral fins on the inner wall of the heat exchange tube is opposite to that of the spiral fins on the outer wall.
  • the liquid reaction material is fed into the reactor through a liquid distributor with an opening rate of 40 ⁇ at a liquid hourly space velocity of 1.1h -1 , and the molar ratio of liquid water to liquid ethylene oxide is 5:1.
  • Ethylene glycol is synthesized in the reactor through a catalytic hydration reaction.
  • the raw material conversion rate is 98.2%
  • the selectivity of ethylene glycol is 98.2%
  • the hot spot temperature rise of the reactor is 4.9°C
  • the pressure drop of the reactor is 163kPa.
  • This comparative example uses a fixed bed reactor similar to that of Example 1 and operating parameters similar to those of Example 1, but the difference is that the rotation direction of the outer wall spiral fins of the straight tube portion of the U-shaped heat exchange tube is all left-handed, and two adjacent U-shaped heat exchange tubes are arranged as shown in Figure 11.
  • the rotation direction of the inner wall spiral fins of the heat exchange tube is the same as that of the outer wall spiral fins, and the pitch of the inner wall spiral fins and the outer wall spiral fins are equal.
  • the liquid reaction material is fed into the reactor at a liquid hourly space velocity of 1.1h -1 through a liquid distributor with an opening rate of 40 ⁇ , wherein the molar ratio of liquid water to liquid ethylene oxide is 5:1, and ethylene glycol is synthesized by catalytic hydration reaction in the reactor.
  • the raw material conversion rate is 98.9%
  • the selectivity of ethylene glycol is 97.6%
  • the hot spot temperature rise of the reactor is 5.7°C
  • the pressure drop of the reactor is 163kPa.
  • This comparative example uses a fixed bed reactor similar to that of Example 1 and operating parameters similar to those of Example 1, but the difference is that the rotation direction of the outer wall spiral fins of the straight tube portion of the U-shaped heat exchange tube is all right-handed, and two adjacent U-shaped heat exchange tubes are arranged as shown in Figure 11.
  • the rotation direction of the inner wall spiral fins of the heat exchange tube is the same as that of the outer wall spiral fins, and the pitch of the inner wall and outer wall spiral fins is equal.
  • the liquid reaction material is fed into the reactor at a liquid hourly space velocity of 1.1h -1 through a liquid distributor with an opening rate of 40 ⁇ , wherein the molar ratio of liquid water to liquid ethylene oxide is 5:1, and ethylene glycol is synthesized by catalytic hydration reaction in the reactor.
  • the raw material conversion rate is 99.0%
  • the selectivity of ethylene glycol is 97.6%
  • the hot spot temperature rise of the reactor is 5.7°C
  • the pressure drop of the reactor is 162kPa.
  • This comparative example uses a fixed bed reactor similar to that of Example 1 and operating parameters similar to those of Example 1, but the difference is that the spiral fins on the outer wall of the straight tube portion of the U-shaped heat exchange tube are all rotated in the left direction, and two adjacent U-shaped heat exchange tubes are arranged as shown in Figure 11. There are no spiral fins on the inner wall of the heat exchange tube.
  • the liquid reaction material passes through the opening rate of 40 ⁇
  • the liquid distributor is fed into the reactor at a liquid hourly space velocity of 1.1h -1 , wherein the molar ratio of liquid water to liquid ethylene oxide is 5:1, and ethylene glycol is synthesized in the reactor by catalytic hydration reaction.
  • the raw material conversion rate is greater than 99.9%
  • the selectivity of ethylene glycol is 94.9%
  • the hot spot temperature rise of the reactor is 9.7°C
  • the pressure drop of the reactor is 162kPa.
  • This comparative example uses a fixed bed reactor similar to that of Example 1 and operating parameters similar to those of Example 1, but the difference is that there are no spiral fins on the outer wall and the inner wall of the U-shaped heat exchange tube.
  • the liquid reaction material is fed into the reactor at a liquid hourly space velocity of 1.1 h -1 through a liquid distributor with an opening rate of 40 ⁇ , wherein the molar ratio of liquid water to liquid ethylene oxide is 5:1, and ethylene glycol is synthesized by catalytic hydration reaction in the reactor.
  • the raw material conversion rate is greater than 99.9%
  • the selectivity of ethylene glycol is 90.2%
  • the hot spot temperature rise of the reactor is 19.8°C
  • the pressure drop of the reactor is 11 kPa.
  • This comparative example uses a fixed bed reactor similar to that of Example 1 and operating parameters similar to those of Example 1, but the difference is that the spiral fins on the outer wall of the straight tube portion of two adjacent U-shaped heat exchange tubes are axially staggered by 1/4 pitch.
  • the liquid reaction material is fed into the reactor at a liquid hourly space velocity of 1.1h -1 through a liquid distributor with an opening rate of 40 ⁇ , and the molar ratio of liquid water to liquid ethylene oxide is 5:1.
  • Ethylene glycol is synthesized in the reactor by catalytic hydration reaction.
  • the raw material conversion rate is 99.5%
  • the selectivity of ethylene glycol is 99.6%
  • the hot spot temperature rise of the reactor is 3.5°C
  • the pressure drop of the reactor is 164kPa.
  • This comparative example uses a fixed bed reactor similar to that of Example 1 and operating parameters similar to those of Example 1, but the difference is that the spiral fins on the outer wall of the straight tube portion of two adjacent U-shaped heat exchange tubes are axially staggered by 1/2 pitch.
  • the liquid reaction material is fed into the reactor at a liquid hourly space velocity of 1.1h -1 through a liquid distributor with an opening rate of 40 ⁇ , and the molar ratio of liquid water to liquid ethylene oxide is 5:1.
  • Ethylene glycol is synthesized by catalytic hydration reaction in the reactor.
  • the raw material conversion rate is 99.1%
  • the selectivity of ethylene glycol is 99.3%
  • the hot spot temperature rise of the reactor is 3.5°C
  • the pressure drop of the reactor is 165kPa.
  • Example 1 The staggered arrangement of the spiral fins on the outer wall of the straight tube portion of two adjacent U-shaped heat exchange tubes in the axial direction does not affect the heat transfer performance.
  • the hot spot temperature rise of Example 1, Example 10 and Example 11 is the same, but the axial misalignment will produce a back-mixing phenomenon, reducing the conversion rate and selectivity of the reaction, and the greater the axial misalignment, the more the conversion rate and selectivity are reduced.
  • Table 2 The results of the above examples are listed in Table 2 below.
  • This embodiment uses a fixed bed reactor similar to that of embodiment 1 and similar operating parameters.
  • the ratio of the pitch H to D H/D is 0.5
  • the corresponding helical lead angle is The liquid material is fed into the reactor through a liquid distributor with an opening rate of 40 ⁇ at a liquid hourly space velocity of 1.1h -1 , wherein the molar ratio of liquid water to liquid ethylene oxide is 5:1, and ethylene glycol is synthesized in the reactor by catalytic hydration reaction.
  • the raw material conversion rate is greater than 99.9%
  • the selectivity of ethylene glycol is greater than 99.9%
  • the hot spot temperature rise of the reactor is 3.5°C
  • the pressure drop of the reactor is 101kPa.
  • the liquid reaction material is fed into the reactor at a liquid hourly space velocity of 1.1h -1 through a liquid distributor with an opening rate of 40 ⁇ , wherein the molar ratio of liquid water to liquid ethylene oxide is 5:1, and ethylene glycol is synthesized in the reactor by catalytic hydration reaction.
  • the raw material conversion rate is greater than 99.9%
  • the selectivity of ethylene glycol is 98.7%
  • the hot spot temperature rise of the reactor is 4.8°C
  • the pressure drop of the reactor is 53kPa.
  • Example 12 The spiral angle of the outer wall spiral fins of Example 12 and Example 13 Similarly, although the pressure drop of the reactor in Example 12 is greater than that of the reactor in Example 13, the hot spot temperature rise of the reactor in Example 12 is lower and the selectivity of ethylene glycol is higher.
  • This embodiment uses a fixed bed reactor similar to that of embodiment 1 and has similar operating parameters as that of embodiment 1, but the difference is that the cross section of the spiral fins on the outer wall of the heat exchange tube is semicircular, the ratio of the semicircular radius to the diameter D of the U-shaped heat exchange tube is 0.08, the ratio of the pitch H to D is 1, and the ratio of the distance W between the centers of two adjacent heat exchange tubes to the diameter D of the U-shaped heat exchange tube is 1.7.
  • the liquid material is fed into the reactor at a liquid hourly space velocity of 0.9h -1 through a liquid distributor with an opening rate of 40 ⁇ , wherein the molar ratio of liquid water to liquid ethylene oxide is 5:1, and ethylene glycol is synthesized in the reactor by catalytic hydration reaction.
  • the raw material conversion rate is greater than 99.9%
  • the selectivity of ethylene glycol is 99.0%
  • the hot spot temperature rise of the reactor is 4.3°C
  • the pressure drop of the reactor is 92kPa.
  • This embodiment uses a fixed bed reactor similar to that of embodiment 1 and has similar operating parameters as that of embodiment 1, but the difference is that the cross section of the spiral fins on the outer wall of the heat exchange tube is rectangular, the side of the rectangle close to the wall is the long side, and its ratio to the diameter D of the U-shaped heat exchange tube is 0.16, the aspect ratio of the rectangle is 2, the ratio of the pitch H to D is 1, and the ratio of the distance W between the centers of two adjacent heat exchange tubes to the diameter D of the U-shaped heat exchange tube is 1.7.
  • the liquid material is fed into the reactor at a liquid hourly space velocity of 0.9h -1 through a liquid distributor with an opening rate of 40 ⁇ , wherein the molar ratio of liquid water to liquid ethylene oxide is 5:1, and ethylene glycol is synthesized in the reactor by catalytic hydration reaction.
  • the raw material conversion rate is greater than 99.9%
  • the selectivity of ethylene glycol is 99.1%
  • the hot spot temperature rise of the reactor is 4.2°C
  • the pressure drop of the reactor is 137kPa.
  • Examples 14 and 15 also confirm that when the cross-section of the spiral fins on the outer wall of the heat exchange tube is rectangular and semicircular, as long as the spiral fins on the outer wall of the adjacently arranged heat exchange tubes are alternating between left-handed and right-handed, the obtained reactor can also make the reaction occurring therein have high conversion rate, high selectivity and low pressure drop.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Geometry (AREA)
  • Thermal Sciences (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Devices And Processes Conducted In The Presence Of Fluids And Solid Particles (AREA)
  • Physical Or Chemical Processes And Apparatus (AREA)

Abstract

一种包括液体分布装置的反应器以及使用该反应器进行多相催化反应的方法，反应器包括：换热管单元，其包括多个竖直布置的换热管（1），至少一部分换热管（1）的外壁上设有左旋或右旋的螺旋翅片（10），并且其中至少一部分换热管（1）的外壁螺旋翅片（10）与其相邻排列的换热管（1）的外壁螺旋翅片（10）的旋转方向相反；并且换热介质在换热管（1）内流动，而液体反应物料在换热管（1）外以几乎平行于换热管（1）轴向方向流动。

Description

包含液体分布装置的固定床反应器和使用这种反应器进行多相催化反应的方法 技术领域
本发明涉及多相催化反应技术领域，特别涉及一种包含液体分布装置的反应器和使用这种反应器进行多相催化反应的方法。
背景技术
多相催化反应是指一种或多种反应物在界面上(如固体催化剂表面上)进行的化学反应。多相催化反应通常在固定床反应器、流动床反应器、移动床反应器、进料床反应器和旋转床反应器中进行。
固定床反应器在化学工业领域有广泛的应用，其具有体积小、反应速率高、易于控制等优点。其中，列管式固定床反应器多用于强放热反应体系，反应器结构与固定管板热交换器相似，管程为反应区，催化剂装填于列管内，物料在通过列管内的催化剂时发生反应，壳程空间充满换热介质，形成反应换热系统。列管式固定床反应器常见的应用包括甲醇合成塔、环氧乙烷反应器、丙烯酸反应器及煤制乙醇反应器等。
Sasol公司及Shell公司相继开发出工业上应用于费托合成的固定床反应器，反应器内部的列管内填充催化剂，列管之间有水以产生蒸汽将热量带出反应器。费托反应是强放热反应，固定床反应器的列管中的径向与轴向均存在温度不均匀的现象。目前用于控制床层温度均匀的办法是减小反应管管径，但在较小的管径中合成气容易在催化剂表面发生积碳反应，出现局部过热的现象，造成催化剂破裂和失活。
在本领域中对列管式固定床反应器的改进是多方面的，包括从传统的固定列管式结构发展到刺刀管式、自冷式、分管束式、板片式、缠绕管式等结构，以在保证换热效果的前提下，提高反应器空间利用率，降低装置能耗和反应器制造难度，提高单台反应器的产能水平。
然而，应用在强放热反应体系中的固定床反应器的传热问题是一个技术难题。研究人员通过改变填料形状、优化流体动力学等手段以提高固定床反应器的热传递效率。
CN101480595B提出采用针型翅片换热列管来同时兼顾流场调控和传热强化两方面效果，一方面针型翅片能降低液速，降低轴向返混， 另一方面翅片能增加换热面积，同时产生的二次扰流能增加换热系数，能抵消因液速降低引起的对流换热系数降低的不良效果。但是，上述措施虽然解决了换热和返混的问题，但针型翅片与催化剂颗粒的碰撞作用将造成催化剂磨损的问题，这将降低催化剂反应性能、削弱催化剂颗粒和液体的分离效率、增加催化剂更换频次等。
固定床反应器主要应用在气-固反应体系中，很少应用于液-固反应体系中。液-固反应体系与气-固反应体系相比，液时空速小，由于液体在密度和黏度方面与气体相差较大，液-固体系的流体运动分布规律与气-固体系的流体运动分布规律相比存在较大的差异。尤其对于强放热的液-固反应体系，由于通常的固定床反应器很难高效地将热量移出反应器，因此通常只能以较低速率进行该反应。
带有螺旋翅片的换热管一般用于具有高流动速度的流体，例如气固反应体系，因为带有螺旋翅片或螺纹的换热管对高速流动的流体产生扰动，使流体边界层不断的被破坏，可有效的提高传热膜系数，产生良好的强化传热效果。例如，中国专利申请CN 209222077公开了一种用于费托合成反应器的传热系统，该传热系统包括换热元件、汽包，换热元件设置在反应器内；其中换热管可以采取三种结构形式，最常用的是光滑的金属管，也可以采用带针翅的金属管或/和带外螺纹槽的金属管；该费托合成反应器为三相浆态床费托合成反应器或流化床费托合成反应器。
乙二醇是一种在化工领域中具有重要用途的脂肪族二元醇。乙二醇通常在固定床反应器中采用多相催化水合工艺进行制备。例如中国专利申请CN101306984A公开了一种用于环氧乙烷催化水合制乙二醇的固定床反应器，其中通过将催化剂装填在U形列管的外侧，使得可以在一定程度上解决催化剂装填后的膨胀问题和优化传热，但是所使用的U形列管容易使管外的反应液体在流动过程中沿着管壁产生沟流效应，会使得液体在固定床径向方向上产生不均匀分布现象，而盘状再分布器对解决沟流现象作用有限。反应液体的沟流现象将影响原料转化率和选择性。同时，沟流效应导致U形管外侧液膜厚度较大，增大了传热阻力，降低了U形列管的传热能力。同时，其U形列管采用不同的规格且进口端和出口端分别位于反应器两侧，反应器床层会因为U形列管这样的分布方式产生温度差，同样将影响反应的转化率和收率。 温度差产生的热应力也会缩短反应器的使用寿命。
为了克服现有技术中的上述问题，亟需一种可有效避免沟流现象发生、且可使催化剂颗粒装填区的反应液体分布更均匀的液体分布装置以及包含该液体分布装置的固定床反应器。
发明内容
本发明人经过研究惊奇地发现，通过使用包含特定的液体分布装置的反应器可以克服上述问题，其中该液体分布装置包含多个特定排列的具有外壁螺旋翅片的换热管；发明人发现将这种反应器用于进行具有低流动速度的反应液体的液固反应体系中时，这种液体分布装置对该液固反应具有强烈的促进作用，显著提高了反应选择性。不受特定理论束缚，发明人认为，这种特定排列的具有外壁螺旋翅片的换热管用于进行具有低流动速度的反应液体料流的液固反应体系中时，外壁螺旋翅片的主要作用是改变流体的流动方向，促进流体在径向上流动，使具有几乎相等停留时间的流体在径向上进行分流和汇合，防止具有不同停留时间的流体在轴向上返混，使得反应物料的温度在径向上的分布是均匀的，进而精确控制反应进程，从而显著提高反应的选择性。发明人进一步地发现，当所述换热管的外壁螺旋翅片为多头螺纹形式时，能在保证甚至强化上述优点的同时，还能显著降低反应器压降，这种发现在现有技术中迄今没有被公开。事实上，基于已公开的文献，本领域技术人员一般认为，由于传热管的外壁螺旋翅片对低速流动的液体的流动状态具有很小的扰动作用，不会破坏流体边界层，对液固反应体系的传质和传热没有明显的影响，尤其对使用非常低的液时空速的固定床反应器的反应性能具有很小的影响，因此不会在使用非常低的液时空速的固定床反应器中选择使用具有外壁螺旋翅片的传热管。
因此，本发明的一个目的在于提供一种包含液体分布装置的反应器，该液体分布装置不仅可以有效避免由在换热管的外壁上发生的沟流现象导致的在固体颗粒装填区中流体分布不均的问题，还可有效减小液固界面的层流层的液膜厚度，以加强反应动力学，另外还可以提升在换热管的外壁与内壁上的强化传热的均匀性，降低传热阻力、热应力及反应器压降。
为实现上述目的，本发明提供一种包含液体分布装置的反应器，特 别地固定床反应器，其允许反应液体在反应器的径向上均匀分布、始终保持活塞流形式，减少反应液体轴向返混，减少反应器压降，同时又能有效移除由反应体系放出的大量热量、降低反应热点温度，使得反应器内温度分布均匀，从而提高反应器的本质安全性。
包含这种液体分布装置的反应器，特别地固定床反应器，尤其适用于使环氧乙烷(液体)与水(液体)在固体树脂催化剂作用下发生反应以生成乙二醇、使环氧乙烷(液体)与乙二醇(液体)在固体树脂催化剂作用下发生反应以生成二乙二醇、使环氧乙烷(液体)与二乙二醇(液体)在固体树脂催化剂作用下发生反应以生成三乙二醇、使环氧丙烷(液体)与水(液体)在固体树脂催化剂作用下发生反应以生成丙二醇、使环氧丁烷(液体)与水(液体)在固体树脂催化剂作用下发生反应以生成丁二醇等过程，在保证反应液体均匀分布的同时还能快速移除反应产生的热量，从而保证反应区的温度分布均匀，能极大程度保证化工过程的本质安全性。
因此，根据本发明的第一方面，本发明提供了一种包括液体分布装置的反应器，特别地固定床反应器，其中所述液体分布装置包括：
换热管单元，其包括多个竖直布置的换热管，其中至少一部分，优选所有的换热管的外壁上设有左旋或右旋的螺旋翅片，其中至少一部分换热管的外壁螺旋翅片与其相邻排列的换热管的外壁螺旋翅片的旋转方向相反(即，至少一部分相邻排列的换热管的外壁螺旋翅片的旋转方向为左旋和右旋的交替)，更优选地所有换热管的外壁螺旋翅片与其相邻排列的换热管的外壁螺旋翅片的旋转方向相反(即，所有相邻排列的换热管的外壁螺旋翅片为左旋与右旋的交替)；换热介质在换热管内流动，而液体反应物料在换热管外以几乎平行于换热管轴向方向流动；
任选的固体颗粒装填单元，其包括填充在换热管之间的空间中的固体颗粒，优选地所述固体颗粒装填单元为填料床或催化剂床，更优选地为催化剂床。
根据本发明的第二方面，本发明还提供了使用上述反应器进行多相催化反应，尤其液固催化反应的方法。
发明人在经过深入研究后还令人惊奇地发现，换热管的外壁局部温度的均匀分布能对反应流体均匀分布起到促进作用；将根据本发明的包含液体分布装置的反应器用于进行液固反应时，由于相邻排列的换 热管的外壁螺旋翅片为左旋与右旋的交替，液体反应物料在相邻排列的换热管的左旋与右旋的外壁螺旋翅片的组合导流作用下不断分流和汇和，限制不同停留时间的反应物料在反应器轴向上返混，使得液体反应物料在径向上的组成分布的均匀性得到显著提高，由此显著提高了该反应的转化率、动力学和选择性；另外，换热管的外壁螺旋翅片还同时提供了反应热量通过换热管的传递速度。
更特别地，液体反应物料在装填在换热管之间的催化剂颗粒的表面上发生反应，并且在相邻排列的换热管的左旋与右旋的外壁螺旋翅片和催化剂颗粒的共同作用下，使液体反应物料在径向上得到进一步均匀混合，使得温度在径向上更均匀分布，进而使得反应物料的组成在径向上更均匀分布，从而显著提高反应动力学和改善反应选择性。
更特别地，当换热管的螺旋翅片为具有螺纹头数n的多头螺纹(n为大于1的正整数)时，如果该多头螺纹的螺距与单头螺纹的螺距相同，在能实现上述技术效果同时，由于多头螺纹翅片的螺旋升角约为单头螺纹的螺旋升角的n倍，因此多头螺纹翅片能更好地对流体在换热管轴向上起导流作用，能显著降低反应器压降。
发明人经过深入研究发现，并不受某种理论限制，对于根据本发明的反应器，当满足以下条件时：所述液体分布装置包含固体颗粒装填单元，所述每根换热管的规格尺寸是相同的且均匀布置，相邻两根U形换热管的进口端和出口端或者两两相邻的四根直管换热管的进口端呈正方形排列，所述正方形的边长为W、所述换热管的直径为D(参看附图5)，所述换热管的外壁螺旋翅片的横截面为三角形，所述三角形的底边长度的一半为h、顶角的一半为θ，所述螺旋翅片的螺距为H和所述换热管的直径为D，固定床高度为l，固体颗粒的数均直径为d；那么螺旋翅片的结构参数、换热管排列结构参数与反应器传热系数和反应器压降分别满足以下关系式(1)和(2)：

在上述式中，特征尺寸De(m)定义为：Re 表示雷诺系数Pr(普朗特数)表示物性常数，α表示反应器的传热系数(W/(m2·K))；ρ表示反应液体的密度(kg/m3)，μ表示反应液体的黏度(Pa·s)；u表示反应液体流速(m/s)，其计算方法如下：设定空速，如1.1h-1，当反应管装填催化剂体积确定时，可以确定进料总体积流量，根据反应器中图5催化剂装填区域重复单元数量计算出单个重复单元进料体积流量，然后用单个重复单元进料体积流量除以单个重复单元截面积即为流速u(由于反应管装填催化剂，反应管截面积会变小，真实的速度会变大，用这种方法计算的速度相当于反应管不装催化剂时，液体通过反应管的空管速度)；W和D如附图5示，分别表示当换热管以正方形方式排列时，W为该正方形的边长(m)、D为所述换热管的直径(m)；H和h分别表示三角形螺旋翅片的螺距(m)和三角形螺旋翅片横截面的底边长度的一半(m)；θ是三角形螺旋翅片顶角角度的一半(单位是弧度)；cp表示液体的定压比热容(J/(kg·℃))，λ表示液体导热系数(W/(m·K))；M和N为无量纲的常数，其中M与换热管的内壁和外壁的旋转翅片的旋转方向有关，不同旋转方向，取值不一样；当所有换热管的外壁螺旋翅片旋转方向相同时，N＝0.37；当换热管的外壁螺旋翅片的旋转方向与换热管的内壁螺旋翅片的旋转方向相反时，M＝1.18，旋转方向相同时，M＝1；当所有换热管的外壁螺旋翅片与其相邻排列的换热管的外壁螺旋翅片的旋转方向相反时，N＝0.88。
对于在反应器中发生的高放热性反应，通过足够高的传热系数α可以有效地控制反应器的热点温升。根据一种优选的实施方案，在上述式(1)中，α>30W/(m2·K)，优选地α>50W/(m2·K)；更优选地α>70W/(m2·K)；还更优选地α>90W/(m2·K)。
由于本发明反应器更适用于低流空时速的液固反应体系，因此根据一种实施方案，在式(1)中，0.6<Re<50，优选地1<Re<35，更优选地2<Re<10。
在上述式(2)中，ΔP表示反应器压降(Pa)，n为螺纹头数(无量纲)，d是催化剂颗粒数均直径(m)，l表示固定床的高度(m)，其它参数的定 义与上述式(1)相同。
对于本发明的反应器，尤其固定床反应器，低的反应器压降能降低能量消耗。根据一种优选的实施方案，在上述式(2)中，ΔP<2000kPa，优选地ΔP<1000kPa，更优选地ΔP<600kPa，更优选地ΔP<300kPa，还更优选地ΔP<150kPa。
经过多次试验验证，上述式特别地适用于在本发明的反应器内液体为层流运动状态的情况，其中当0.6<Re<50，且1<Pr<3时，计算误差在正负15％以内，甚至大部分在正负10％以内。由于随着温度的升高，Pr会降低，因此对于在本发明的反应器中的液体(温度大于80℃)，Pr均满足此要求。
根据本发明的第三方面，本发明还提供了一种用于改善固定床反应器温度分布的方法，其中在该固定床反应器中使用本发明的液体分布装置。
根据本发明的第四方面，本发明还提供了一种用于降低固定床反应器压降的方法，其中在该固定床反应器中使用本发明的液体分布装置，其中液体分布装置包含具有为多头螺纹形式的外壁螺旋翅片的换热管。
附图说明
图1是根据本发明的一种实施方案的反应器的结构示意图。
图2是根据本发明的一种实施方案的液体分布装置的组装结构示意图(未显示螺旋翅片)。
图3是根据本发明的具有外壁螺旋翅片的换热管的示意图和螺旋翅片的局部放大图。
图4是根据本发明的具有外壁螺旋翅片的换热管的截面示意图(螺旋翅片截面形状为等腰三角形)。
图5是根据本发明的换热管的排列位置和催化剂装填区域的示意图。
图6是根据本发明的液体反应物料分布器的结构示意图。
图7是根据本发明的相邻排列的两个换热管的左旋与右旋的外壁螺旋翅片的局部结构示意图。
图8是根据本发明的具有外壁与内壁螺旋翅片的换热管的截面示意图(螺旋翅片的截面形状为等腰三角形)。
图9是换热管的外壁螺旋翅片与换热管的内壁螺旋翅片的旋转方向相反的示意图，其中，外壁螺旋翅片(实线表示)是右旋的，管内壁螺旋翅片(虚线表示)是左旋的。
图10是换热管的外壁螺旋翅片与换热管的内壁螺旋翅片的旋转方向相同的示意图，其中，外壁螺旋翅片(实线表示)是右旋的，管内壁螺旋翅片(虚线表示)是右旋的。
图11是全部具有右旋的外壁螺旋翅片的换热管排列时的反应流体流动效果图。
图12是具有左旋的外壁螺旋翅片的换热管与具有右旋的外壁螺旋翅片的换热管以轴向非对称方式交替排列时的反应流体流动效果图。
图13是具有左旋的外壁螺旋翅片的换热管与具有右旋的外壁螺旋翅片的换热管以轴向对称方式交替排列时的反应流体流动效果图。
图14是换热管的外壁螺旋翅片分别为单头螺纹和多头螺纹的结构示意图，其中右边图显示螺距为3H的单头螺纹，左边图显示螺距为H的单头螺纹，中间图显示螺距为H且螺纹头数n＝3的多头螺纹。
主要附图标记说明：
100：固定床反应器，
101：液体出口；
1：U形换热管，
1A：换热介质入口，
1B：换热介质出口，
10：螺旋翅片，
10A：左旋螺旋翅片，
10B：右旋螺旋翅片，
11：换热管上支撑板，
12：换热管下支撑板，
13：换热介质进口总管，
14：换热介质出口总管；
2：液体反应物料分布器，
21：出液孔；
3：催化剂装填区域，
31：催化剂顶部筛网，
32：催化剂底部筛网。
具体实施方案
本发明的其它特征和优点将在随后结合附图对本发明的具体实施方案进行详细说明。
应当理解的是，在本说明书中所描述的具体实施方案仅用于说明和解释本发明，并不用于限制本发明。
在本说明书中所披露的任何具体数值(包括数值范围的端点)都不限于该数值的精确值，而应当理解为还涵盖了接近该精确值的值，例如在该精确值±5％范围内的所有可能的数值。并且，对于所披露的数值范围而言，在该范围的端点值之间、端点值与范围内的具体点值之间，以及各具体点值之间可以任意组合而得到一个或多个新的数值范围，这些新的数值范围也应被视为在本说明书中具体公开。
除非另有说明，本说明书所用的术语具有与本领域技术人员通常所理解的相同的含义，如果术语在本说明书中有定义，且其定义与本领域的通常理解不同，则以本说明书的定义为准。
在本说明书中，除了明确说明的内容之外，未提到的任何事宜或事项均直接适用本领域已知的那些而无需进行任何改变。而且，本说明书描述的任何实施方案均可以与本说明书描述的一种或多种其他实施方案自由结合，由此形成的技术方案或技术思想均视为本发明原始公开或原始记载的一部分，而不应被视为是本说明书未曾披露或预期过的新内容，除非本领域技术人员认为该结合明显不合理。
在本说明书中提及的所有专利和非专利文献，包括但不限于教科书和期刊文章等，均通过引用方式全文并入本说明书。
根据本发明的第一方面，本发明涉及一种包括液体分布装置的反应器，特别是固定床反应器，所述液体分布装置包括：
换热管单元，其包括多个竖直布置的换热管，其中至少一部分，优选所有的换热管的外壁上设有左旋或右旋的螺旋翅片，其中至少一部分换热管的外壁螺旋翅片与其相邻排列的换热管的外壁螺旋翅片的旋转方向相反(换句话说，至少一部分相邻排列的换热管的外壁螺旋翅片的旋转方向为左旋和右旋的交替)，更优选地所有换热管的外壁螺旋翅片与其相邻排列的换热管的外壁螺旋翅片的旋转方向相反(换句话说， 所有相邻排列的换热管的外壁螺旋翅片为左旋与右旋的交替)；换热介质在换热管内流动，而液体反应物料在换热管外以几乎平行于换热管轴向方向流动；
任选的固体颗粒装填单元，其包括填充在换热管之间的空间中的固体颗粒。
根据本发明的一种实施方案，所述反应器优选是用于液-固反应体系的固定床反应器，所述固体床可以为固体填料床或固体催化剂床，其包括填充在任何换热管外侧的空间中的为颗粒形式的填料或固体催化剂。
根据本发明的一种实施方案，所述换热管单元包括多个竖直布置的换热管，所述换热管选自直管换热管或U形换热管，优选为U形换热管；在每个换热管的外壁上设有左旋或右旋的螺旋翅片，其中至少一部分换热管的外壁螺旋翅片与其相邻排列的换热管的外壁螺旋翅片的旋转方向相反(换句话说，至少一部分相邻排列的换热管的外壁螺旋翅片的旋转方向为左旋和右旋的交替)，更优选地所有换热管的外壁螺旋翅片与其相邻排列的换热管的外壁螺旋翅片的旋转方向相反(换句话说，所有相邻排列的换热管的外壁螺旋翅片为左旋与右旋的交替)。
应该理解的是，当所述换热管为U形换热管时，U形换热管的直管部分的外壁螺旋翅片的旋转方向可以是彼此相同或不同的，这时，一根具有外壁螺旋翅片的U形换热管等同于两根具有相同或相反旋转方向的外壁螺旋翅片的直管换热管。
在本说明书中，术语“相邻排列的换热管”表示这样排列的两根换热管：它们的轴心距离比它们与其它换热管的轴心距离更小，那么这两根换热管为相邻排列；如果一根换热管的轴心同时与多根换热管的轴心的距离相同并最小时，则该换热管同时与所述多根换热管相邻排列。
根据一种优选实施方案，当所述螺旋翅片的螺距为H、所述换热管的直径为D时，比率H/D为0.2-1.7，优选0.3-1.3，例如0.4、0.5、0.6、0.7、0.8、0.9、1.0、1.1和1.2，其中上述H和D以相同的长度单位计。
根据一种优选实施方案，所述每根换热管的规格尺寸相同且在液体分布装置中均匀布置，优选地相邻两根U形换热管或者两两相邻的四根直管换热管的进口端和/或出口端呈正方形排列，其中所述正方形的边长为W、所述换热管的直径为D，使得W/D＝1.2-3，优选为1.5-2.5， 更优选为1.8-2.4，例如1.9、2.0、2.1、2.2和2.3，其中上述W和D以相同的长度单位计。
根据一种优选实施方案，所述换热管的直径D以及壁厚可以由本领域技术人员根据实际需要和基于其基本知识进行确定，例如直径D通常可以为7-35mm；优选为10-25mm，壁厚可以为约1mm。
根据一种优选实施方案，液体反应物料在换热管外自上向下流动，整体流动方向优选地与换热管轴线基本平行。
发明人经过研究后还惊奇地发现，在本发明的液体分布装置中，固体颗粒，如催化剂颗粒的结构特征(特别地颗粒球形度和数均直径)与所述换热管的外壁螺旋翅片的结构特征的组合对于进一步提高本发明的反应器的性能具有协同作用，使得本发明的固定床反应器非常适合用于进行液固催化反应。根据一种具体的实施方案，所述催化剂床包含近球形的且粒径基本相等的固体催化剂颗粒，具有为大于0.8，优选地大于0.85，更优选地大于0.9的球形度。球形度根据本领域熟知的表面积法进行测量。优选地，固体催化剂的颗粒的数均直径为d，使得d/W为0.01-0.2，优选地0.02-0.1，其中上述W和d以相同的长度单位计。
根据一种优选实施方案，所述换热管为U形换热管，其中每根U形换热管的进口端和出口端位于同一侧且间隔设置，优选地，位于反应器的上端一侧。并且所述换热管的上、下两端均设有支撑板，以使换热管保持竖立。
根据一种优选实施方案，在至少一部分，优选全部换热管的内壁上设有螺旋翅片，换热管的外壁螺旋翅片与换热管的内壁螺旋翅片的旋转方向可以是相同的或相反的，优选是相反的。
根据一种优选实施方案，所述螺旋翅片为在换热管的外壁和/或内壁上的凸起结构，其中该凸起结构的截面形状为三角形、半圆形、半椭圆形或矩形，当该凸起结构的截面形状为三角形时，优选为近等腰三角形，更优选地为等腰三角形；术语“近等腰三角形”表示螺旋翅片的横截面从外壁和/或内壁上的凸起的两个边的长度相差小于10％，优选小于5％，更优选地为相等的。
根据一种优选实施方案，当该凸起结构的截面形状为三角形时，所述三角形的底边长度的一半为h、且顶角的一半为θ，比率h/D为0.03-0.1，优选0.05-0.09，且θ为10°至60°，优选20°至50°，例如25°、 30°、35°、40°或45°，其中角θ的上述度数与弧度可以相互换算。
根据一种优选实施方案，外壁螺旋翅片的旋转方向与换热管的内壁螺旋翅片的旋转方向可以是相同或相反的，优选是相反的。
根据一种优选实施方案，所有换热管的外壁螺旋翅片具有相同的螺距H，相同的截面形状；所有换热管的内壁螺旋翅片具有相同的螺距H，相同的截面形状。
根据一种优选实施方案，外壁螺旋翅片的螺距H与换热管的内壁螺旋翅片的螺距H'可以是相同的或不同的。然而，发明人发现，当换热管的内壁螺旋翅片的螺距H'为外壁螺旋翅片的螺距H的1-5倍，优选2-3倍时是特别有利的，这是因为这使得可以显著简化内壁螺旋翅片制造工艺和节约制造成本，而不会影响，甚至更有利于换热管的传热效率、温度的均匀分布和液体反应物料在换热管外的均匀分布。
根据一种优选实施方案，如果换热管的外壁螺旋翅片的旋转方向与换热管的内壁螺旋翅片的旋转方向是相同的并且换热管的外壁螺旋翅片的螺距H与换热管的内壁螺旋翅片的螺距H'是相同的，这时有利地使换热管的外壁螺旋翅片与该换热管的内壁螺旋翅片在轴向上错位至少1/4个螺距，优选1/2个螺距；或者如果换热管的外壁螺旋翅片的旋转方向与换热管的内壁螺旋翅片的旋转方向是相反的并且换热管的外壁螺旋翅片的螺距H与换热管的内壁螺旋翅片的螺距H'是相同的，这时有利地使换热管的外壁螺旋翅片与换热管的内壁螺旋翅片在轴向上错位至多1/4个螺距，优选不存在错位。
根据一种优选实施方案，当换热管的外壁螺旋翅片的H/D为一定值时，所述外壁螺旋翅片可以为单头螺纹形式或多头螺纹形式，优选地，换热管的外壁螺旋翅片的螺纹头数n为1、2、3或4，优选为3或4。
根据一种优选实施方案，液体分布装置还包含液体分布器，该液体分布器位于所述换热管单元上方，并且所述液体分布器出液孔的开孔率为2‰-75‰，优选10‰-60‰，例如20‰、30‰、40‰、50‰。
根据一种优选实施方案，任一对相邻排列的换热管的左旋与右旋的外壁螺旋翅片在轴向上有至多1/3螺距，优选地至多1/4螺距的错位，更优选地，任一对相邻排列的换热管的左旋与右旋的外壁螺旋翅片在轴向上没有错位，即它们相对于轴向成镜像对称分布。
根据一种优选实施方案，所述固体颗粒装填单元的上、下两端均设 有筛网；下端的筛网设于所述换热管底部的下方，这样可以防止催化剂颗粒从筛网与带有外壁旋转翅片的换热管接触处的缝隙漏出，上端的筛网设于液体分布器的下方。
根据一种优选实施方案，所述反应器的换热介质进口总管和/或换热介质出口总管位于反应器顶部，且其设置位置高于液体分布器。
根据一种优选实施方案，本发明的反应器为多相催化反应器，用于催化水合反应以制备乙二醇、催化反应以制备二乙二醇、催化反应以制备三乙二醇、催化反应以制备丙二醇、或催化反应以制备丁二醇，其中所述液体反应物料分别为液态环氧乙烷和液态水、液态环氧乙烷和液态乙二醇，液态环氧乙烷和液态二乙二醇，液态环氧丙烷和液态水，或液态环氧丁烷和液态水；并且所使用的固体催化剂选自树脂。
根据本发明的第二方面，本发明还涉及一种进行多相催化反应的方法，其特征在于，使用如上所述的反应器，特别是固定床反应器。
根据一种优选实施方案，所述方法用于通过环氧乙烷催化水合反应制备乙二醇、通过环氧乙烷与乙二醇催化反应制备二乙二醇、通过环氧乙烷与二乙二醇催化反应制备三乙二醇、通过环氧丙烷催化水合反应制备丙二醇、或通过环氧丁烷催化水合反应制备丁二醇等，其中所述液体反应物料分别为液态环氧乙烷和液态水、液态环氧乙烷和液态乙二醇，液态环氧乙烷和液态二乙二醇，液态环氧丙烷和液态水，或液态环氧丁烷和液态水；并且所使用的固体催化剂选自树脂。
根据一种优选实施方案，所述方法用于通过环氧乙烷催化水合反应制备乙二醇，其中液体反应物料为液态环氧乙烷和液态水，并且采用的固体催化剂为树脂。
根据一种优选实施方案，所述方法用于通过环氧乙烷催化水合反应制备乙二醇，其中液体反应物料为液态环氧乙烷和液态水，液态水和液态环氧乙烷的摩尔含量比为小于或等于10:1，优选小于或等于6:1，例如为5:1、4:1、3:1。
根据一种优选实施方案，液态环氧乙烷和液态水流动通过固定床反应器，与装填在换热管外侧的固体催化剂床接触并反应生成乙二醇，其中反应温度为85-150℃，优选90-140℃、压力为1.0-1.8MPa，优选1.1-1.7MPa，例如1.2MPa、1.4MPa、1.6MPa，液时空速为0.5-5h-1，优选为1-4h-1，例如2h-1、3h-1。
在本领域的现有技术中，具有外壁螺旋翅片的换热管一般用于换热器中，而且通常采用如图11所示的外壁螺旋翅片全部为右旋或左旋的排列方式。然而，发明人经过研究发现，将具有外壁螺旋翅片的换热管用于固定床反应器中，并且使反应流体物料在换热管外以平行于换热管轴向方向流动，这使得可以在有效传热的同时，能显著改善反应流体的反应动力学，控制其反应速度，并显著提高其反应收率和选择性。
发明人进一步发现，当排列的换热管的外壁螺旋翅片全部为右旋时，流体会有向左偏流的趋势，反应流体流动效果如图11所显示。同样，当排列的换热管的外壁螺旋翅片全部为左旋时，流体会有向右偏流的趋势。由于单向流动的反应流体缺乏相互交汇混合，因此如此流动产生的效果是在催化剂填充空间中的反应流体的温度在径向上分布不均，进而使得液体在固定床的径向方向上产生其组成和温度都非均匀分布的现象，严重影响反应的动力学、收率和反应选择性。
发明人还发现，如图12所示，当在换热管单元中具有左旋外壁螺旋翅片的换热管与具有右旋外壁螺旋翅片的换热管是相邻交替排列，但所述两根换热管的外壁螺旋翅片在轴向上有超过三分之一螺距的错位时，虽然反应流体在反应器径向方向上产生分流与汇聚交替出现的流动效果，但a流股和b流股仍然具有不同的流通路径，两者在反应器内停留时间不同，汇聚时将出现返混效应。反应流体的流动效果如图12所示。
如图13所示，当在换热管单元中具有左旋外壁螺旋翅片的换热管与具有右旋外壁螺旋翅片的换热管相邻交替排列，并且所述相邻交替排列的两根换热管的外壁螺旋翅片在轴向上成镜像对称分布时，则在这种结构中流动的流体流过这种具有镜像对称关系的流道并具有相同的停留时间，使得反应流体的温度在反应器的径向上分布非常均匀，进而使得反应流体在反应器的径向上的组成分布也是均匀的，且螺旋翅片对流体有向前促进流动的导向作用，能减少甚至避免具有不同停留时间的液体在轴向上返混。反应流体的流动效果如图13所示。
发明人进一步发现，如图14所示，换热管单元的外壁螺旋翅片的螺距对传热能力也有较大影响。螺距H越小，换热管单元传热能力越好，反应器热点温升越小，反应选择性越高，反应性能越好。但是，单头螺纹H越小，螺纹的螺旋升角随之降低，流体经过螺纹时在换热 管的轴向上遇到的阻力会变大，会使得整个反应器压降过大。当使用多头螺纹时，在与单头螺纹相同螺距H时，在保证了相同甚至更好的传热效果同时，还能显著减小反应器压降，优化流体在换热管的外壁螺旋翅片上流动状态，提升反应器的反应性能。在图14中，左边图和右边图显示了外壁螺旋翅片为螺纹头数n＝1的单头螺纹，中间图显示了外壁螺旋翅片为螺纹头数n＝3的多头螺纹。右边图的螺距较大，传热能力较差，中间图的螺距为右边图螺距的1/3，传热能力得到加强，但是中间图的螺纹的螺旋升角约为左边图螺旋升角的3倍，促进了流体在轴向上的流动，显著减小了反应器的压降。
根据本发明的液体分布装置特别地适用于固定床反应器，尤其适用于进行具有低液时空速的液-固多相催化反应的固定床反应器。根据一种优选的实施方案，如图2所示，液体分布装置包括多个竖向均匀排列的规格尺寸相同的U形换热管，使得U形换热管的进、出口端间隔设置成正方形；换热介质在U形换热管中流通并在U形换热管外侧填充固体催化剂颗粒以形成催化剂床；液体反应物料自上而下均匀进入固体催化剂颗粒床所在空间并在换热介质的控温作用下进行催化反应；在反应过程中，U形换热管的外壁螺旋翅片能防止液体反应物料的沿着U形换热管外壁的沟流，保持液体反应物料在固体催化剂床中的均匀分布。换热管的外壁螺旋翅片与内壁螺旋翅片的旋转方向相反，使得能提升所述螺旋翅片对换热管的外壁与内壁强化传热的均匀性，降低传热阻力及热应力；进一步地，换热管的外壁局部温度均匀分布能对反应流体的组成的均匀分布起到促进作用。在所述换热管单元中，具有左旋外壁螺旋翅片的换热管与具有右旋外壁螺旋翅片的换热管相邻交替排列，能显著提升反应流体的组成和温度分布的均匀性，从而提高反应器的性能。相邻交替排列的换热管的外壁螺旋翅片在轴向上成镜像对称分布，汇聚的流体由于所述具有镜像对称关系的流道而具有相同的停留时间，因此避免了具有不同停留时间的流体在汇聚时的返混效应。
与现有技术相比，根据本发明的反应器具有如下有益效果：
1)在现有技术中，液体反应物料在流经催化剂床时，由于催化剂颗粒之间存在空隙，很容易在换热管的光滑外壁的位置产生连续的空隙，液体在这样的位置会形成“短路”，即液体物料的流动容易集中在换热管的外壁上并发生沟流现象。在换热管的外壁上的沟流现象会导致流体 在催化剂颗粒装填区中的分布不均匀的问题。本发明在换热管的外壁上设置螺旋翅片，通过螺旋翅片的引流作用，可有效引导沿换热管的外壁流动的液体物料朝径向方向流动，避免液体物料在外壁上发生在轴向上的沟流，从而使流体在催化剂颗粒装填区的分布更为均匀；同时，还可有效降低换热管的外壁的液膜厚度，降低传热阻力，能有效地提高传热能力；
2)经研究，发明人还发现，螺旋翅片的构造只要凸出于换热管的外壁即可引导液体反应物料沿径向流动，但当螺旋翅片的横截面为等腰三角形时，这种引导流体的效果更佳；经发明人进一步研究发现，引导流体的效果与等腰三角形的底边以及顶角等指标密切相关；在本发明中采用的等腰三角形的底边h相对于换热管直径的尺寸D的比值h/D的特定取值范围以及顶角θ的特定角度范围不仅可以有效避免在换热管的外壁上的沟流现象，提高催化反应的传质传热能力，还不会对流体流动通过催化剂床时产生过大阻力，从而降低了反应器压降；
3)经研究，发明人还发现，如果在换热管的内壁上设置螺旋翅片，使内壁螺旋翅片的位置不与外壁螺旋翅片的位置重合布置，并且使换热管的外壁螺旋翅片与内壁螺旋翅片的旋转方向相反时，能让内壁和外壁螺旋翅片覆盖的区域更加对称。这种布置方式的换热管的螺旋翅片与外壁围绕组成的区域是关于换热管的中心轴呈对称性分布，这种对称性有效提升螺旋翅片对换热管的外壁与内壁强化传热的均匀性，避免换热管的外壁和内壁局部温差过大，减少热应力，减少由于热应力而产生的变形对换热管的使用寿命的不利影响。同时，换热管的外壁局部温度的均匀分布能对反应流体的均匀分布起到促进作用。
4)经研究，发明人还发现，在换热管单元中，具有左旋的外壁螺旋翅片的换热管与具有右旋的外壁螺旋翅片的换热管相邻交替排列，这种布置方式使得换热管在竖直方向上呈现对称性，这种对称结构能对反应流体的流动方向起引导作用，且由于相邻的换热管的外壁螺旋翅片的旋转方向相反，让液体物料在反应器径向方向上产生分流与汇聚交替出现的流动效果，避免液体物料向单一方向偏流，从而使流体在催化剂颗粒装填区中的分布更为均匀。且螺旋翅片还对流体有向前流动的导向作用，能有效减少轴向液体返混。以上这些流动效果的综合作用能有效提高反应器转化率和选择性。若换热管单元中所有的换热管的 外壁螺旋翅片为一种旋转方向时，如螺旋翅片全部为左旋或者螺旋翅片全部为右旋的情况，由于换热管的外壁螺旋翅片的旋转方向一致，虽然能引导沿换热管的外壁流动的液体物料朝径向方向流动，但是由于所有的螺旋翅片的旋转方向一致，从而会导致液体物料有向一个方向偏流的趋势，从而影响流体在各个方向的均匀分布。
5)经研究，发明人还发现，相邻交替排列的具有左旋或右旋外壁螺旋翅片的换热管在轴向上成镜像对称分布，汇聚的流体流动通过具有镜像对称关系的流道，从而具有相同的停留时间，因此不存在具有不同停留时间的流体在汇聚时的返混效应。若将相邻交替排列的具有左旋或右旋外壁螺旋翅片的在轴向上相对移动一段距离，且此距离与螺距不成整数倍关系，这将导致相邻排列的换热管的外壁螺旋翅片在轴向上出现错位排列，不具有相对于轴向的镜像对称关系。此时，由于汇聚的流体具有不同的流通路径，其在汇聚时在反应器内的停留时间不一样，将导致流体出现具有不同停留时间的流体返混效应，降低反应的转化率和选择性；
6)在换热管单元中使用U形换热管时，将每根U形换热管的进口端和出口端设于同一侧且均匀间隔布置，由于每根换热管采用相同的尺寸规格，使得液体分布装置的整体结构更为合理并且使在反应器内的径向温差控制在更小值。相对于现有技术中的U形换热管出口和进口分别对称地布置在反应器径向两侧、导致反应器两侧存在较明显的温差，本发明可有效提高在反应器的径向上的反应均匀性，而且避免由大的径向温差引起的额外热应力使反应器产生热变形，提高了反应器使用寿命；
7)本发明将相邻两根U形换热管的进、出口端呈正方形布置，并且将正方形的边长W与换热管的直径D的比值W/D设置为一定范围内，通过试验证明，这种布置方式相对于矩形或菱形等布置方式，本发明的正方形布置方式可进一步提高液体反应物料在催化剂床中的流动均匀性；
8)根据本发明的换热管的外壁螺旋翅片的螺纹头数为多头时，相比于单头螺纹，在相同的螺距H下，多头螺纹螺旋升角更大，螺旋翅片对换热管外流体具有更多的轴向导流效应，能明显降低反应器压降。
9)本发明将催化剂床下端的筛网设置在换热管底部的下方，可有效 降低由换热管穿过筛网可能引起的催化剂泄漏风险，降低反应器制造加工难度；
10)本发明提出了用于计算带螺旋翅片的反应器传热和压降的无因次准数关联式，且计算误差满足工程使用要求。
11)本发明尤其适用于多相催化反应的固定床反应器中，即反应物料均为液相且催化剂为固体催化剂颗粒的应用场景；特别适用于通过环氧乙烷的催化水合反应制备乙二醇、环氧乙烷与乙二醇催化反应以制备二乙二醇，环氧乙烷与二乙二醇催化反应以制备三乙二醇，环氧丙烷的催化水合反应制备丙二醇，环氧丁烷的催化水合反应制备丁二醇等的过程中。
上述说明仅仅是对本发明技术方案的概括描述，为了能够更清楚地了解本发明的技术方案并可依据说明书的内容进行实施，同时为了使本发明的上述和其他目的、技术特征以及优点更加易懂，以下列举了多个优选实施例和对比例，并配合附图进行详细说明。
除非另有其他明确表示，否则在整个说明书和权利要求书中，术语“包括”或其变换如“包含”或“包括有”等等将被理解为包括所陈述的元件或组成部分，而并未排除其他元件或其他组成部分。
在本说明书中，为了描述的方便，可以使用空间相对术语，诸如“下面”、“下方”、“下”、“上面”、“上方”、“上”等，来描述一个元件或特征与另一元件或特征在附图中的关系。应理解的是，空间相对术语旨在包含除了在图中所绘的方向之外物件在使用或操作中的不同方向。例如，如果在图中的物件被翻转，则被描述为在其他元件或特征“下方”或“下”的元件将取向在所述元件或特征的“上方”。因此，示范性术语“下方”可以包含下方和上方两个方向。物件也可以有其他取向(旋转90度或其他取向)且应对本说明书使用的空间相对术语作出相应的解释。
如图1-图14所示，本发明提供了一种其中换热管为U形换热管的液体分布装置的实施方案，其主要应用于多相催化反应体系中，特别适用于液体物料在固体催化剂床的作用下且在较温和的反应温度下(例如100℃左右)的催化反应，例如环氧乙烷多相催化水合制备乙二醇的反应、环氧乙烷与乙二醇催化反应以制备二乙二醇、环氧乙烷与二乙二醇催化反应以制备三乙二醇、环氧丙烷多相催化水合反应制备丙二醇、或通过环氧丁烷多相催化水合反应制备丁二醇等。由于此类反应为强放热 反应，反应过程中为了保持相对稳定的反应温度，需要使用换热管单元，通过向换热管单元的换热管通入换热介质(冷却或加热)来控制反应温度。
如图1所示，本发明U形换热管1的上、下两端设有支撑板，即换热管的上支撑板11和换热管的下支撑板12。通过上、下支撑板的作用，由换热管1形成的阵列可牢固安装在反应器的有效空间中。催化剂床上、下两端均可设有筛网，即图1中的催化剂顶部筛网31和催化剂底部筛网32。这样可将填充后的催化剂颗粒限制在换热管1之间的有效区域内。优选地而非限制性地，催化剂底部筛网32设于换热管1的底部下方。由于本发明催化反应液体物料从反应器顶部进入，因此反应器顶部筛网不存在泄漏问题。为了防止催化剂从反应器底部筛网泄漏，将U形换热管1底部设于底部筛网32上方，即不穿过催化剂筛网，能有效降低由U形换热管穿过筛网引起的催化剂泄漏所引发的风险，并降低反应器制造加工难度。
根据一种具体实施方案，本发明的液体分布装置包括：换热管单元和催化剂床。换热管单元中的换热管为U形换热管，且其数量为多个，并且被竖直布置，每根U形换热管1的进口端(即图2中的换热介质进口1A)和出口端(即图2中的换热介质出口1B)位于同一侧且间隔设置。“进口端和出口端位于同一侧”是指采用相同规格的换热管进行规则排列，这样可以形成进口-出口-进口-出口的排列方式，使得液体分布装置整体的结构更为合理并且使在反应器内的径向温差被控制为更小值。相对于现有技术中的U形换热管出口和进口分别布置在反应器径向两侧、导致反应器两侧存在较明显的温差，本发明可有效提高反应器径向截面上反应的均匀性，避免由径向温差引起的额外热应力使反应器产生热变形，并提高反应器使用寿命。换热管的外壁设有螺旋翅片10(参考图3)，进一步地，优选地而非限制性地，螺旋翅片可以为换热管的外壁的凸起结构，该凸起结构的横截面可以为三角形、半圆形、半椭圆形或矩形等形状。设置螺旋翅片的目的是不但解决在现有技术中液体在U形管外壁发生的沟流现象致使催化剂颗粒装填区流体分布不均匀的问题，而且使流体沿着反应器的径向流动，促进流体的组成和温度在径向上的均匀分布。在换热管1内通入换热介质，用于保持和控制催化反应需要的温度。催化剂床实际占据着在换热管单元中在换热管外侧的 空间(参考图5中的催化剂装填区域3)，该空间内填充固体催化剂颗粒；液体反应物料在所述空间内流动从而进行催化反应。
在现有技术中，液体反应物料在催化剂床中流动时，由于催化剂颗粒之间存在空隙，很容易在换热管的光滑外壁的位置产生连续的空隙，液体在这样的位置会形成“短路”，即液体物料容易集中在换热管的外壁上发生沟流现象。由于在U形换热管的外壁的沟流现象会导致流体在催化剂中的分布不均匀的问题，因此，本发明在U形换热管的外壁上设置螺旋翅片，通过螺旋翅片的作用，可有效引导沿换热管的外壁流动的液体物料朝径向方向流动，避免发生沟流现象，从而使流体在催化剂颗粒装填区中的分布更为均匀。同时，由于避免了沟流现象，可有效降低在换热管的外壁的液膜的厚度，降低传热阻力，从而更为有效地提高传热能力。
进一步如图3和图4所示，优选地而非限制性地，螺旋翅片10的凸起结构的横截面可以为等腰三角形。经研究，发明人还发现，螺旋翅片10只要凸出于换热管1外壁即可引导液体反应物料沿径向流动，但当螺旋翅片的横截面为等腰三角形时，引导液体的效果更佳。经研究，发明人进一步发现，引导液体的效果还与等腰三角形的底边以及顶角等指标密切相关。当螺旋翅片10的螺距为H、换热管1的直径(不含螺旋翅片高度)为D时，根据本发明，比值H/D在0.2-1.7范围内，优选为0.3-1.3，例如0.4、0.5、0.6、0.7、0.8、0.9、1.0、1.1和1.2。当等腰三角形的底边长度的一半为h、且顶角的一半为θ时，比值h/D在0.03-0.1范围内，优选0.05-0.09，例如0.05、0.06、0.07和0.08，且θ在10°至60°范围内，优选为20°至50°，例如20°、25°、30°、35°、40°、45°或50°。发明人通过进一步研究发现，本发明采用的等腰三角形的底边h相对于换热管直径D的尺寸的比值h/D的范围以及顶角θ的角度范围不仅可以有效避免在换热管的外壁上的沟流现象，提高反应器的传质传热能力，而且还不会对流体在轴向上的流动产生较大阻力。在h固定的前提下，θ过大，翅片结构较平滑，会降低螺旋翅片对液体的扰动作用，使得在径向上的引导流动的作用有限，将使螺旋翅片减少在换热管的外壁上的沟流现象的能力和强化传热的能力下降。θ过小，螺旋翅片的结构过于尖锐，相当于在流体前方增加了凸起障碍物，将对流体轴向流动产生较大阻力，使得流体在螺旋翅片的上方和下方产生较厚的 停滞层，同样也会降低螺旋翅片的强化传质的能力。采用具有上述尺寸的螺旋翅片可以进一步优化上述技术效果。
进一步如图5所示，优选地而非限制性地，相邻两根U形换热管采用紧密布置的方式(参考图5左侧图)，两根换热管的进口端、出口端可呈正方形排列，并且两两相邻的换热管的外壁螺旋翅片的旋转方向相反；当正方形的边长为W、换热管的直径为D时，使得比值W/D为1.2-3，优选为1.5-2.5，优选为1.8-2.4，例如1.8、1.9、2.0、2.1、2.2和2.3。经研究，发明人还发现，两根U形换热管1的轴心连线距离(也即正方形边长W)越大，装填催化剂空间越大，反应器生产能力越大，但是单位体积催化剂对应的传热面积会降低，W越小，装填催化剂空间越小，反应器生产能力变小，但是单位体积催化剂对应的传热面积会增加，有助于移除在反应中的产生的热量，避免温升过高，减少副反应的发生，同时也能提高反应器的本质安全特性。本发明采用正方形排列方式，且使正方形的边长W与换热管的直径D的比值在上述范围内，试验证明，相对于矩形或菱形布置方式，正方形的布置方式可进一步提高液体反应物料在催化剂装填区域中的流动均匀性，同时可有效降低反应器的热点温升。而且由于在本发明的反应器中采用特定的液体分布装置，使得本发明的反应器的生产能力显著提高。
进一步如图8至图10所示，在换热管的内壁也设有螺旋翅片，优选地而非限制性地，换热管的外壁螺旋翅片与内壁螺旋翅片的旋转方向相反。通过进一步研究发现，当换热管的外壁螺旋翅片与内壁螺旋翅片的旋转方向相反时，并且当换热管的外壁螺旋翅片与内壁螺旋翅片的螺距没有错位时，如图9所示，能使由螺旋翅片所覆盖的区域更加对称。这种布置方式的螺旋翅片与换热管的外壁围绕所形成的区域关于换热管的中心轴呈现一定的对称性，这种对称性能有效提升螺旋翅片对换热管的外壁与内壁的强化传热的均匀性，避免换热管的外壁和内壁局部温差过大，减少热应力，降低由热应力引起的变形对换热管使用寿命的不利影响。同时，换热管的外壁局部温度均匀分布能对反应流体均匀分布起到促进作用。换热管的外壁螺旋翅片与内壁螺旋翅片的旋转方向相同，且有1/2螺距错位时，如图10所示，螺旋翅片与换热管的外壁围绕所形成的区域关于换热管的中心轴不呈现对称性，不具备图9所示结构的优点。
进一步如图11和图13所示，优选地而非限制性地，在换热管单元中，具有左旋的外壁螺旋翅片的换热管与具有右旋的外壁螺旋翅片的换热管相邻交替排列，并且相邻交替排列的换热管在轴向上成镜像对称分布。发明人通过进一步研究发现，这种布置方式使得换热管在反应器的轴向上呈现一定的对称性，这种对称结构能对反应流体在径向方向上的均匀分布起到较好的作用，且当相邻排列的换热管的外壁螺旋翅片的旋转方向相反时，这能使流过螺旋翅片的液体物料在反应器径向方向上产生分流与汇聚交替出现的流动效果。避免由于全部换热管的外壁螺旋翅片为一个旋转方向时所引起的液体物料向单一方向偏流。液体物料在具有这种具有左旋的外壁螺旋翅片的换热管与具有右旋的外壁螺旋翅片的换热管相邻交替排列的结构的反应器内流动时，流体在汇聚时的停留时间是相同的，不会出现由于具有不同停留时间的流体返混效应而导致的低原料转化率和低选择性。
进一步如图14所示，优选地而非限制性地，换热管的外壁螺旋翅片的螺纹头数n大于1，优选螺纹头数n为2、3或4。发明人通过研究发现，与单头螺纹相比，为多头螺纹形式的螺旋翅片在相同螺距H下，具有更大的螺旋升角，对换热管外的反应流体具有更好的轴向导流作用，能显著降低反应器压降。
本发明的液体分布装置尤其适用于多相催化反应。多相催化反应器可以选自通过催化水合制备乙二醇的反应器、通过环氧乙烷与乙二醇催化反应以制备二乙二醇的反应器、通过环氧乙烷与二乙二醇催化反应以制备三乙二醇的反应器、催化水合制备丙二醇的反应器、催化水合制备丁二醇的反应器；液体反应物料可以为液态环氧乙烷和液态水、液态环氧乙烷和液态乙二醇、液态环氧乙烷和液态二乙二醇、液态环氧丙烷和液态水，或液态环氧丁烷和液态水；所使用的固体催化剂可选自树脂。
根据一种优选的实施方案，如图1和2所示，本发明还提供了一种固定床反应器(固定床未显示)，其包括前述的液体分布装置。固定床反应器的换热介质进口总管13和换热介质出口总管14均位于反应器顶部，其设置位置高于液体分布器。所有U形换热管的换热介质入口1A与换热介质进口总管13相连，所有U形换热管的换热介质出口1B与换热介质出口总管14相连。进一步地，液体分布器2位于反应器上方， 反应流体的流动方向与反应器轴线平行。进一步参考图6，液体分布器2的出液孔21优选设置在固体颗粒装填单元上方的中间区域，这样可以保证下行的液体物料尽量在催化剂装填区域的均匀分布。分布器出液孔的开孔率可以为2‰-75‰。
本发明还提供了一种应用前述的固定床反应器的反应方法，其中所述固定床反应器适用于进行多相催化反应，其包括多个竖向均匀排列的规格尺寸相同的U形换热管，其中U形换热管的进、出口端间隔设置；U形换热管的内壁和外壁均设有螺旋翅片；在U形换热管中通入换热介质并在U形换热管外侧填充固体催化剂颗粒以形成固体催化剂床；自上而下均匀进入固体催化剂床中的液体反应物料在换热介质的控温作用下在催化剂表面进行催化反应；反应过程中，通过U形换热管的外壁螺旋翅片防止在外壁上出现沟流现象，以保持固体催化剂床中的液相均匀分布。换热管的外壁螺旋翅片与内壁螺旋翅片的旋转方向相反，由换热管的外壁螺旋翅片与换热管的外壁围绕组成的区域关于换热管的中心轴呈现对称性，这种对称性可以有效提升螺旋翅片对换热管的外壁与内壁强化传热的均匀性，避免换热管的外壁和内壁局部温差过大，减少热应力。通过使在换热管单元中的具有左旋的外壁螺旋翅片的换热管与具有右旋的外壁螺旋翅片的换热管相邻交替排列，且相邻交替排列的具有左旋的外壁螺旋翅片的换热管与具有右旋的外壁螺旋翅片的换热管在轴向上成镜像对称分布，使流过螺旋翅片的液体物料产生分离和汇聚的效果，从而保证液体在固体催化剂床中在径向上的均匀分布，同时螺旋翅片对流体流动导向作用能加强液体在径向上的流动同时减少在轴向上的返混。以上效果能提高原料转化率和反应选择性。优选地而非限制性地，该反应方法可用于通过环氧乙烷催化水合反应以制备乙二醇、环氧乙烷与乙二醇催化反应以制备二乙二醇、环氧乙烷与二乙二醇催化反应以制备三乙二醇、环氧丙烷催化水合反应以制备丙二醇、环氧丁烷催化水合反应以制备丁二醇等。在制备乙二醇的过程中，液体反应物料采用液态环氧乙烷和液态水，所采用的固体催化剂选自树脂；其中在85～150℃的反应温度、1.0～1.8MPa的压力、0.5～5h-1的空速条件下，液体反应物料在本发明的固定床反应器中，与装填在换热管外侧的固体催化剂接触并反应，以高选择性和高产率地生成乙二醇。
实施例
以下实施例用来举例说明本发明的较优选的技术方案，因此对本发明的保护范围绝没有限定性质；其中在这些实施例中，原料转化率通过对反应器进口和出口环氧乙烷浓度变化进行计算；环氧乙烷的浓度采用气相色谱进行测量；乙二醇的选择性通过对反应器出口乙二醇浓度测量值进行计算；和反应器的热点温升如下进行测量：在图5中所示的正中心催化剂床层内插入套管，将热电偶插入套管内，进行上下移动，该热点温升最大值通常出现在催化剂床上部，即催化剂床顶面到热点距离为催化剂床高度20％左右位置；但是热点位置会随着液时空速、原料配比等工艺条件变化而变化。反应器压降为反应流体入口和出口压力差值，用压差计测量。其它参数的测量均按本领域的常规方法进行。
实施例1
本实施例使用一种如图1所示的用于多相催化水合制备乙二醇的固定床反应器，反应器直径为500mm，固定床高度为1300mm；在其中包含多根U形换热管，其直径D为15mm，壁厚为1mm；其中U形换热管的外壁上设置有其横截面为等腰三角形的螺旋翅片，在换热管的内壁上设置有其横截面为等腰三角形的螺旋翅片，一部分换热管的外壁螺旋翅片为左旋，另一部分换热管的外壁螺旋翅片为右旋。换热管的内壁螺旋翅片和外壁螺旋翅片均为螺纹头数n＝1的单头螺纹形式。同一换热管的管内壁螺旋翅片与外壁螺旋翅片的旋转方向相反且螺距相等。在换热管单元中，具有左旋的外壁螺旋翅片的换热管与具有右旋的外壁螺旋翅片的换热管相邻交替排列，如图13所示，相邻两根U形换热管镜像对称排列。外壁螺旋翅片与换热管的内壁螺旋翅片的横截面相同，其中h与U形换热管直径D的比值h/D为0.08，θ为30°。螺距H与D的比值H/D为0.5，其对应的螺旋升角为14°。每两根U形换热管以正方形方式进行排列，相邻两根换热管轴心连线距离W与U形换热管直径D的比值W/D为2，液体分布器开孔率40‰。在催化剂单元中包含球形树脂催化剂颗粒，其球形度为0.85，其数均直径d使得比值d/D约为0.1。液体反应物料通过开孔率为40‰的液体分布器以1.1h-1的液时空速进料到反应器中，其中液体水和液体环氧乙烷摩尔比为5:1，在所述反应器中通过催化水合反应合成乙二醇。经过测量，对 于在该固定床反应器中进行的合成乙二醇的反应，原料转化率大于99.9％，乙二醇的选择性大于99.9％，反应器的热点温升为3.5℃，反应器压降为165kPa。
实施例2
本实施例使用与实施例1相似的固定床反应器和与实施例1相似的操作参数，但不同在于θ为45°。液体物料通过开孔率为40‰的液体分布器以1.1h-1的液时空速被进料到反应器中，其中液体水和液体环氧乙烷摩尔比为5:1，在所述反应器中通过催化水合反应合成乙二醇。经过测量，对于在该反应器中进行的合成乙二醇的反应，原料转化率大于99.9％，乙二醇的选择性99.7％，反应器的热点温升为3.7℃，反应器压降为135kPa。
实施例3
本实施例使用与实施例1相似的固定床反应器和与实施例1相似的操作参数，但不同在于h与U形换热管直径D的比值h/D为0.04。液体物料通过开孔率为40‰的液体分布器以1.1h-1的液时空速被进料到反应器中，其中液体水和液体环氧乙烷摩尔比为5:1，在所述反应器中通过催化水合反应合成乙二醇。经过测量，对于在该反应器中进行的合成乙二醇的反应，原料转化率大于99.9％，乙二醇的选择性99.5％，反应器的热点温升为3.8℃，反应器压降为126kPa。
实施例4
本实施例使用与实施例1相似的固定床反应器和与实施例1相似的操作参数，但不同在于相邻两根换热管中心连线距离W与U形换热管直径D的比值W/D为2.5。液体物料通过开孔率为40‰的液体分布器以1.1h-1的液时空速被进料到反应器中，液体水和液体环氧乙烷摩尔比为5:1，在所述反应器中通过催化水合反应合成乙二醇。经过测量，对于在该反应器中进行的合成乙二醇的反应，原料转化率大于99.9％，乙二醇的选择性99.0％，反应器的热点温升为4.2℃，反应器压降为105kPa。
实施例5
本实施例使用与实施例1相似的固定床反应器和与实施例1相似的操作参数，但不同在于螺距H与D的比值H/D为1。液体物料通过开孔率为40‰的液体分布器以1.1h-1的液时空速被进料到反应器中， 液体水和液体环氧乙烷摩尔比为5:1，在所述反应器中通过催化水合反应合成乙二醇。经过测量，对于在该反应器中进行的合成乙二醇的反应，原料转化率大于99.9％，乙二醇的选择性99.2％，反应器的热点温升为4.0℃，反应器压降为80kPa。
实施例6
本实施例使用与实施例1相似的固定床反应器和与实施例1相似的操作参数，但不同在于螺距H与D的比值H/D为1和相邻两根换热管中心连线距离W与U形换热管直径D的比值W/D为1.7。液体物料通过开孔率为40‰的液体分布器以1.1h-1的液时空速被进料到反应器中，液体水和液体环氧乙烷摩尔比为5:1，在所述反应器中通过催化水合反应合成乙二醇。经过测量，对于在该反应器中进行的合成乙二醇的反应，原料转化率大于99.9％，乙二醇的选择性99.8％，反应器的热点温升为3.6℃，反应器压降为129kPa。
实施例7
本实施例使用与实施例1相似的固定床反应器和与实施例1相似的操作参数，但不同在于螺距H与D的比值H/D为1.5，相邻两根换热管中心连线距离W与U形换热管直径D的比值W/D为1.7，θ为20°。液体物料通过开孔率为40‰的液体分布器以1.1h-1的液时空速被进料到反应器中，液体水和液体环氧乙烷摩尔比为5:1，在所述反应器中通过催化水合反应合成乙二醇。经过测量，对于在该反应器中进行的合成乙二醇的反应，原料转化率大于99.9％，乙二醇的选择性99.2％，反应器的热点温升为4.1℃，反应器压降为101kPa。
实施例8
本实施例使用与实施例1相似的固定床反应器和与实施例1相似的操作参数，但不同在于螺距H与D的比值H/D为1，相邻两根换热管中心连线距离W与U形换热管直径D的比值W/D为2.2，h与U形换热管直径D的比值h/D为0.1，θ为20°。液体物料通过开孔率为40‰的液体分布器以1.1h-1的液时空速被进料到反应器中，液体水和液体环氧乙烷摩尔比为5:1，在所述反应器中通过催化水合反应合成乙二醇。经过测量，对于在该反应器中进行的合成乙二醇的反应，原料转化率大于99.9％，乙二醇的选择性98.9％，反应器的热点温升为4.5℃，反应器压降为83kPa。
实施例9
本实施例使用与实施例1相似的固定床反应器和与实施例1相似的操作参数，但不同在于同一换热管的管内壁螺旋翅片与外壁螺旋翅片的旋转方向相同且螺距相等换热管。液体物料通过开孔率为40‰的液体分布器以1.1h-1的液时空速被进料到反应器中，其中，液体水和液体环氧乙烷摩尔比为5:1，在所述反应器中通过催化水合反应合成乙二醇。经过测量，对于在该反应器中进行的合成乙二醇的反应，原料转化率大于99.9％，乙二醇的选择性为99.0％，反应器的热点温升为4.2℃，反应器压降为167kPa。
通过使实施例9和实施例1进行比较可见，由于在实施例1中使用的反应器包括的换热管的内壁螺旋翅片的旋转方向与外壁螺旋翅片的旋转方向相反，因此根据实施例1的反应器的原料转化率和乙二醇的选择性均比实施例9的相应参数更高，并且实施例1的反应器的热点温度更低。这说明了在反应器中的换热管的内壁螺旋翅片的旋转方向与外壁螺旋翅片的旋转方向对于反应器的性能具有协同效应。
对比例1
本对比例使用与实施例1相似的固定床反应器和与实施例1相似的操作参数，但不同在于所有U形换热管的直管部分的外壁螺旋翅片的旋转方向全部为右旋，并且使任何相邻两根U形换热管如图11所示进行排列；换热管的内壁螺旋翅片的旋转方向与换热管的外壁螺旋翅片的旋转方向相反。液体反应物料通过开孔率为40‰的液体分布器以1.1h-1的液时空速被进料到反应器中，液体水和液体环氧乙烷摩尔比为5:1，在所述反应器中通过催化水合反应合成乙二醇。经过测量，对于在该反应器中进行的合成乙二醇的反应，原料转化率为98.2％，乙二醇的选择性为98.3％，反应器的热点温升为4.9℃，反应器压降为162kPa。
对比例1外壁螺旋翅片排列方式不是左右旋交替排列，使得流动形态变差，虽然热点温度变大，但是转化率下降较多。
对比例2
本对比例使用与实施例1相似的固定床反应器和与实施例1相似的操作参数，但不同在于U形换热管的直管部分的外壁螺旋翅片的旋转方向全部为左旋，并且使相邻两根U形换热管如图11所示进行排列。换热管的内壁螺旋翅片的旋转方向与外壁螺旋翅片的旋转方向相 反。液体反应物料通过开孔率为40‰的液体分布器以1.1h-1的液时空速被进料到反应器中，液体水和液体环氧乙烷摩尔比为5:1，在所述反应器中通过催化水合反应合成乙二醇。经过测量，对于在该反应器中进行的合成乙二醇的反应，原料转化率为98.2％，乙二醇的选择性为98.2％，反应器的热点温升为4.9℃，反应器压降为163kPa。
对比例3
本对比例使用与实施例1相似的固定床反应器和与实施例1相似的操作参数，但不同在于U形换热管的直管部分的外壁螺旋翅片的旋转方向全部为左旋，并且使相邻两根U形换热管如图11所示进行排列。换热管的内壁螺旋翅片的旋转方向与外壁螺旋翅片的旋转方向相同，内壁螺旋翅片和外壁螺旋翅片的螺距相等。液体反应物料通过开孔率为40‰的液体分布器以1.1h-1的液时空速被进料到反应器中，其中液体水和液体环氧乙烷摩尔比为5:1，在所述反应器中通过催化水合反应合成乙二醇。经过测量，对于在该反应器中进行的合成乙二醇的反应，原料转化率为98.9％，乙二醇的选择性为97.6％，反应器的热点温升为5.7℃，反应器压降为163kPa。
对比例4
本对比例使用与实施例1相似的固定床反应器和与实施例1相似的操作参数，但不同在于U形换热管的直管部分的外壁螺旋翅片的旋转方向全部为右旋，并且使相邻两根U形换热管如图11所示进行排列。换热管的内壁螺旋翅片的旋转方向与外壁螺旋翅片的旋转方向相同，内壁和外壁螺旋翅片的螺距相等。液体反应物料通过开孔率为40‰的液体分布器以1.1h-1的液时空速被进料到反应器中，其中液体水和液体环氧乙烷摩尔比为5:1，在所述反应器中通过催化水合反应合成乙二醇。经过测量，对于在该反应器中进行的合成乙二醇的反应，原料转化率为99.0％，乙二醇的选择性为97.6％，反应器的热点温升为5.7℃，反应器压降为162kPa。
对比例5
本对比例使用与实施例1相似的固定床反应器和与实施例1相似的操作参数，但不同在于U形换热管的直管部分的外壁螺旋翅片的旋转方向全部为左旋，并且使相邻两根U形换热管如图11所示进行排列。在换热管的内壁上没有螺旋翅片。液体反应物料通过开孔率为40‰ 的液体分布器以1.1h-1的液时空速被进料到反应器中，其中液体水和液体环氧乙烷摩尔比为5:1，在所述反应器中通过催化水合反应合成乙二醇。经过测量，对于在该反应器中进行的合成乙二醇的反应，原料转化率为大于99.9％，乙二醇的选择性为94.9％，反应器的热点温升为9.7℃，反应器压降为162kPa。
通过使对比例4和5与实施例1的实验结果进行比较可见，在换热管单元中，具有左旋的外壁螺旋翅片的换热管与具有右旋的外壁螺旋翅片的换热管相邻交替排列能使催化剂颗粒装填区的流体分布更均匀，能显著提高原料转化率和选择性，并显著降低反应器的热点温度。
对比例6
本对比例使用与实施例1相似的固定床反应器和与实施例1相似的操作参数，但不同在于U形换热管的外壁上和内壁上均没有螺旋翅片。液体反应物料通过开孔率为40‰的液体分布器以1.1h-1的液时空速被进料到反应器中，其中液体水和液体环氧乙烷摩尔比为5:1，在所述反应器中通过催化水合反应合成乙二醇。经过测量，对于在该反应器中进行的合成乙二醇的反应，原料转化率为大于99.9％，乙二醇的选择性为90.2％，反应器的热点温升为19.8℃，反应器压降为11kPa。
对比例1到对比例6，随着热点温升变大，反应转化率变大，但是选择性下降。上述实施例和对比例结果列于下表1中。
表1
实施例10
本对比例使用与实施例1相似的固定床反应器和与实施例1相似的操作参数，但不同在于相邻两根U形换热管的直管部分的外壁螺旋翅片在轴向上错位1/4螺距。液体反应物料通过开孔率为40‰的液体分布器以1.1h-1的液时空速被进料到反应器中，液体水和液体环氧乙烷摩尔比为5:1，在所述反应器中通过催化水合反应合成乙二醇。经过测量，对于在该反应器中进行的合成乙二醇的反应，原料转化率为99.5％，乙二醇的选择性为99.6％，反应器的热点温升为3.5℃，反应器压降为164kPa。
实施例11
本对比例使用与实施例1相似的固定床反应器和与实施例1相似的操作参数，但不同在于相邻两根U形换热管的直管部分的外壁螺旋翅片在轴向上错位1/2螺距。液体反应物料通过开孔率为40‰的液体分布器以1.1h-1的液时空速被进料到反应器中，液体水和液体环氧乙烷摩尔比为5:1，在所述反应器中通过催化水合反应合成乙二醇。经过测量，对于在该反应器中进行的合成乙二醇的反应，原料转化率为99.1％，乙二醇的选择性为99.3％，反应器的热点温升为3.5℃，反应器压降为165kPa。
相邻两根U形换热管的直管部分的外壁螺旋翅片在轴向上的错位排列不影响传热性能，实施例1、实施例10和实施例11的热点温升相同，但是轴向错位会产生返混现象，降低反应的转化率和选择性，且轴向错位越大，转化率和选择性降低越多。上述实施例的结果列在下表2中。
表2
实施例12
本实施例使用与实施例1相似的固定床反应器和相似的操作参数。本实施例的换热管的外壁螺旋翅片的螺距和实施例1中的外壁螺旋翅片的螺距相等，但不同在于外壁螺旋翅片的螺纹头数n＝3。螺距H与D的比值H/D为0.5时，其对应的螺旋升角为36.9°。液体物料通过开孔率为40‰的液体分布器以1.1h-1的液时空速被进料到反应器中，其中液体水和液体环氧乙烷摩尔比为5:1，在所述反应器中通过催化水合反应合成乙二醇。经过测量，对于在该反应器中进行的合成乙二醇的反应，原料转化率大于99.9％，乙二醇的选择性大于99.9％，反应器的热点温升为3.5℃，反应器压降为101kPa。
通过实施例1和实施例12的对比可见，实施例12中的螺旋翅片的螺旋升角比实施例1的螺旋升角大2.6倍，实施例12中的螺旋翅片的螺纹头数n＝3的螺旋翅片能降低反应器压降39％左右。
实施例13
本实施例使用与实施例1相似的固定床反应器和相似的操作参数，且换热管的外壁螺旋翅片的螺纹头数n＝1，但不同在于外壁螺旋翅片的螺距H与换热管直径D的比值H/D为1.5。液体反应物料通过开孔率为40‰的液体分布器以1.1h-1的液时空速被进料到反应器中，其中液体水和液体环氧乙烷摩尔比为5:1，在所述反应器中通过催化水合反应合成乙二醇。经过测量，对于在该反应器中进行的合成乙二醇的反应，原料转化率大于99.9％，乙二醇的选择性为98.7％，反应器的热点温升为4.8℃，反应器压降为53kPa。
实施例12和实施例13的外壁螺旋翅片的螺旋升角相同，虽然实施例12中的反应器压降比实施例13反应器压降更大，但是实施例12的反应器的热点温升更低，乙二醇的选择性更高。
表3
实施例14
本实施例使用与实施例1相似的固定床反应器与实施例1相似的操作参数，但不同在于换热管的外壁螺旋翅片的横截面为半圆形，半圆半径与U形换热管直径D的比值为0.08，螺距H与D的比值H/D为1，相邻两根换热管中心连线距离W与U形换热管直径D的比值W/D为1.7。液体物料通过开孔率为40‰的液体分布器以0.9h-1的液时空速被进料到反应器中，其中液体水和液体环氧乙烷摩尔比为5:1，在所述反应器中通过催化水合反应合成乙二醇。经过测量，对于在该反应器中进行的合成乙二醇的反应，原料转化率大于99.9％，乙二醇的选择性为99.0％，反应器的热点温升为4.3℃，反应器压降为92kPa。
实施例15
本实施例使用与实施例1相似的固定床反应器与实施例1相似的操作参数，但不同在于换热管的外壁螺旋翅片的横截面为矩形，矩形靠近壁面一侧为长边，其与U形换热管直径D的比值为0.16，矩形的长宽比为2，螺距H与D的比值H/D为1，相邻两根换热管中心连线距离W与U形换热管直径D的比值W/D为1.7。液体物料通过开孔率为40‰的液体分布器以0.9h-1的液时空速被进料到反应器中，其中液体水和液体环氧乙烷摩尔比为5:1，在所述反应器中通过催化水合反应合成乙二醇。经过测量，对于在该反应器中进行的合成乙二醇的反应，原料转化率大于99.9％，乙二醇的选择性为99.1％，反应器的热点温升为4.2℃，反应器压降为137kPa。
上述实施例14和15也证实了当换热管的外壁螺旋翅片的横截面为矩形和半圆形时，只要相邻排列的换热管的外壁螺旋翅片是左旋和右旋交替，获得的反应器也能使得在其中发生的反应具有高转化率，高选择性和低的压降。
前述对本发明的实施例的描述是为了说明本发明的技术方案的目的和优点。这些描述并非想将本发明限定为所公开的特定形式，并且很显然，根据上述教导，本领域技术人员可以进行很多改变和变化。对实施例进行选择和描述的目的在于说明本发明的技术方案的实际应用和相对于现有技术的优势，从而使得本领域的技术人员能够实施并利用本发明的各种不同的实施方案以及进行各种不同的选择和改变。针对上述实施方案所做的任何简单修改、等同变化与修饰，都应落入本发明的保护范围。

Claims (20)

  1. 一种包括液体分布装置的反应器，优选为固定床反应器，其特征在于所述液体分布装置包括：
    换热管单元，其包括多个竖直布置的换热管，至少一部分，优选所有换热管的外壁上设有左旋或右旋的螺旋翅片，并且其中至少一部分换热管的外壁螺旋翅片与其相邻排列的换热管的外壁螺旋翅片的旋转方向相反，优选地所有换热管的外壁螺旋翅片与其相邻排列的换热管的外壁螺旋翅片的旋转方向相反；并且换热介质在换热管内流动，而液体反应物料在换热管外以几乎平行于换热管轴向方向流动；
    任选的固体颗粒装填单元，其包括填充在所述换热管之间的空间中的固体颗粒。
  2. 根据权利要求1所述的反应器，其特征在于，所述换热管选自直管换热管或U形换热管，其中该U形换热管的直管部分的外壁螺旋翅片的旋转方向可以是相同或不同的，并且其中每根U形换热管的进口端和出口端间隔设置，优选地所述换热管的上、下两端均设有支撑板。
  3. 根据权利要求1-2中任一项所述的反应器，其特征在于，在至少一部分，优选全部换热管的内壁上设有螺旋翅片，其中换热管的外壁螺旋翅片的旋转方向与换热管的内壁螺旋翅片的旋转方向是相同或相反的，优选是相反的。
  4. 根据权利要求3所述的反应器，其特征在于，所述换热管的外壁和/或内壁螺旋翅片为在换热管的外壁和/或内壁上的凸起结构，其中该凸起结构的截面形状为三角形、半圆形、半椭圆形或矩形，优选为等腰三角形。
  5. 根据权利要求1或2所述的反应器，其特征在于，所述液体分布装置包含固体颗粒装填单元，所述每根换热管的规格尺寸是相同的且均匀布置，相邻两根U形换热管的进口端和出口端或者两两相邻的四根直管换热管的进口端呈正方形排列，所述正方形的边长为W、所述换热管的直径为D，所述换热管的外壁螺旋翅片的横截面为三角形，所述三角形的底边长度的一半为h、顶角的一半为θ，所述螺旋翅片的螺距为H和所述换热管的直径为D，固定床高度为l，这时包含该液体分布装置的反应器传热系数与螺旋翅片的结构参数、换热管排列结构 参数满足以下关系式(1)：
    在上述式中，De表示以m计的特征尺寸：Re表示雷诺系数：并且使得0.6<Re<50；；α表示反应器的以W/(m2·K)计的传热系数，并且使得α>30W/(m2·K)；ρ表示反应液体的以kg/m3计的密度，μ表示反应液体的以Pa·s计的黏度；u表示反应液体的以m/s计的流速，其计算方法如下：根据预定的液体空速和在反应器中装填的催化剂体积，可以确定进料总体积流量，根据反应器中催化剂装填区域重复单元数量计算出单个重复单元进料体积流量，然后用单个重复单元进料体积流量除以单个重复单元截面积即为流速u；W、D、H、h和l均以单位m计；θ以弧度计；Pr表示物性常数，其中cp表示液体的以J/(kg·℃)计的定压比热容，λ表示液体的以W/(m·K)计的导热系数；M和N为无量纲的常数，当所有换热管的外壁螺旋翅片旋转方向相同时，N＝0.37，当所有换热管的外壁螺旋翅片与其相邻排列的换热管的外壁螺旋翅片的旋转方向相反时，N＝0.88；当换热管的外壁螺旋翅片的旋转方向与换热管的内壁螺旋翅片的旋转方向相反时，M＝1.18，旋转方向相同时，M＝1。
  6. 根据权利要求1或2所述的反应器，其特征在于，所述液体反应装置包含固体颗粒装填单元，所述每根换热管的规格尺寸是相同的且均匀布置，相邻两根U形换热管的进口端和出口端或者两两相邻的四根直管换热管的进口端呈正方形排列，所述正方形的边长为W、所述换热管的直径为D，所述换热管的螺旋翅片的横截面为三角形，所述三角形的底边长度的一半为h、顶角的一半为θ，所述螺距为H和所述换热管的直径为D，固定床高度为l，d是固体颗粒数均直径，n为每根换热管的螺旋翅片的螺纹头数，这时螺旋翅片的结构参数、换热管排列结构参数与反应器压降满足以下关系式(2)：
    在上述式中，De表示以m计的特征尺寸：Re表示雷诺系数并且使得0.6<Re<50；ΔP表示以Pa计的反应器压降，其中ΔP<2000kPa；ρ表示以kg/m3计的反应液体的密度，μ表示以Pa·s计的反应液体的黏度；u表示以m/s计的反应液体流速，其计算方法如下：根据预定的液体空速和在反应器中装填的催化剂体积，可以确定进料总体积流量，根据反应器中催化剂装填区域重复单元数量计算出单个重复单元进料体积流量，然后用单个重复单元进料体积流量除以单个重复单元截面积即为流速u；W、D、H、h、l和d的单位为m；θ以弧度计；n表示螺旋翅片的螺纹头数，为无量纲参数。
  7. 根据权利要求1-6中任一项所述的反应器，其特征在于，所述每根换热管的规格尺寸是相同的且均匀布置，相邻两根U形换热管的进口端和出口端或者两两相邻的四根直管换热管的进口端呈正方形排列，当所述正方形的以m计的边长为W、所述换热管的以m计的直径为D时，使得W/D＝1.2-3，优选为1.5-2.5，更优选为1.8-2.4。
  8. 根据权利要求1-7中任一项所述的反应器，其特征在于，所述换热管的外壁螺旋翅片的螺距是相等的，当所述螺旋翅片的以m计的螺距为H、所述换热管的以m计的直径为D时，使得比率H/D为0.2-1.7，优选0.3-1.3。
  9. 根据权利要求4-8中任一项所述的反应器，其特征在于，当所述凸起结构的截面形状为三角形时，所述三角形的以m计的底边长度的一半为h、且顶角的一半为θ，使得比率h/D为0.03-0.1，优选0.05-0.09，且θ为10°至60°，优选20°至50°。
  10. 根据权利要求8所述的反应器，其特征在于，在H/D为一定值时，所述换热管的外壁螺旋翅片为单头螺纹形式或多头螺纹形式，其中所述螺旋翅片的螺纹头数n大于或等于1，优选地所述螺纹头数n为 2、3或4。
  11. 根据权利要求1-10中任一项所述的反应器，其特征在于，所述反应器是用于液-固反应体系的固定床反应器，所述固体颗粒装填单元选自固体填料床或固体催化剂床，其包括填充在任何相邻两根换热管之间的空间中的为颗粒形式的填料或催化剂。
  12. 根据权利要求1-11中任一项所述的反应器，其特征在于，该液体分布装置还包含液体分布器，所述液体分布器位于所述换热管单元上方或下方，并且所述液体分布器出液孔的开孔率为2‰-75‰。
  13. 根据权利要求1-12中任一项所述的反应器，其特征在于，所有换热管的外壁螺旋翅片与其相邻排列的换热管的外壁螺旋翅片在轴向上有至多1/3螺距，优选地至多1/4螺距的错位，优选地，所有换热管的外壁螺旋翅片与其相邻排列的换热管的外壁螺旋翅片在轴向上成镜像对称分布。
  14. 根据权利要求1-13中任一项所述的反应器，其特征在于，所述催化剂床上、下两端均设有筛网，并且下端的筛网设于所述换热管底部下方。
  15. 根据权利要求1-14中任一项所述的反应器，其特征在于，所述反应器的换热介质进口总管和/或换热介质出口总管位于反应器顶部，且其设置位置高于液体分布器。
  16. 根据权利要求1-15中任一项所述的反应器，其特征在于，所述反应器为固定床反应器，用于催化水合制备乙二醇、催化反应以制备二乙二醇、催化反应以制备三乙二醇、催化水合制备丙二醇，或催化水合制备丁二醇等，其中所述液体反应物料分别为液态环氧乙烷和液态水、液态环氧乙烷和液态乙二醇、液态环氧乙烷和液态二乙二醇、液态环氧丙烷和液态水，或液态环氧丁烷和液态水等，优选地，所使用的固体催化剂选自树脂。
  17. 一种进行多相催化反应的方法，其特征在于，使用如权利要求1-16中任一项所述的反应器。
  18. 根据权利要求17所述的方法，其特征在于，所述方法用于通过环氧乙烷催化水合反应制备乙二醇、通过环氧乙烷与乙二醇催化反应制备二乙二醇、通过环氧乙烷与二乙二醇催化反应制备三乙二醇、通过环氧丙烷催化水合反应制备丙二醇、或通过环氧丁烷催化水合反应 制备丁二醇等。
  19. 根据权利要求18所述的方法，其特征在于，液体反应物料为液态环氧乙烷和液态水，并且使用树脂作为固体催化剂。
  20. 根据权利要求19所述的方法，其特征在于，在85-150℃的反应温度、1.0-1.8MPa的压力、0.5-5h-1的液时空速条件下，使液体反应物料通过固定床反应器，与装填在换热管之间的固体催化剂接触反应以生成乙二醇。
PCT/CN2024/101844 2023-07-03 2024-06-27 包含液体分布装置的固定床反应器和使用这种反应器进行多相催化反应的方法 Ceased WO2025007792A1 (zh)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CN202310810224.8A CN119236804B (zh) 2023-07-03 2023-07-03 传热组件以及应用该组件的固定床反应器、反应方法
CN202310810224.8 2023-07-03

Publications (1)

Publication Number Publication Date
WO2025007792A1 true WO2025007792A1 (zh) 2025-01-09

Family

ID=94033202

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2024/101844 Ceased WO2025007792A1 (zh) 2023-07-03 2024-06-27 包含液体分布装置的固定床反应器和使用这种反应器进行多相催化反应的方法

Country Status (2)

Country Link
CN (1) CN119236804B (zh)
WO (1) WO2025007792A1 (zh)

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5916531A (en) * 1997-04-29 1999-06-29 Pan; Chuen Yong Spiral fixed-bed module for adsorber and catalytic reactor
CN202403593U (zh) * 2012-01-16 2012-08-29 安吉恒盛热能机械有限公司 一种内螺纹槽换热管结构
CN111569787A (zh) * 2020-05-13 2020-08-25 万华化学集团股份有限公司 一种列管式固定床反应器及其在烯烃环氧化反应中的应用
CN115624919A (zh) * 2022-11-08 2023-01-20 中国科学院过程工程研究所 一种浆态床反应器及其应用

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1767807C3 (de) * 1968-06-20 1975-04-10 Basf Ag, 6700 Ludwigshafen Verfahren und Vorrichtung zur indirekten Zuführung von Wärme in zwei aufeinanderfolgenden Reaktionsräumen
CN101279230B (zh) * 2007-04-04 2010-05-19 中国石油化工股份有限公司 均温液-固相催化反应器
CN105582859B (zh) * 2014-10-24 2019-06-11 中国石油化工股份有限公司 催化氨化法制乙醇胺的方法
CN205462152U (zh) * 2016-03-19 2016-08-17 江苏怡达化学股份有限公司 直接氧化法制备环氧丙烷的绿色合成反应装置
CN214681631U (zh) * 2020-12-10 2021-11-12 青岛科技大学 防结块的u型管有机硅流化床反应器
CN114225850B (zh) * 2021-11-09 2023-12-26 青岛科技大学 一种有机硅单体合成流化床反应器中防结碳的方法和装置

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5916531A (en) * 1997-04-29 1999-06-29 Pan; Chuen Yong Spiral fixed-bed module for adsorber and catalytic reactor
CN202403593U (zh) * 2012-01-16 2012-08-29 安吉恒盛热能机械有限公司 一种内螺纹槽换热管结构
CN111569787A (zh) * 2020-05-13 2020-08-25 万华化学集团股份有限公司 一种列管式固定床反应器及其在烯烃环氧化反应中的应用
CN115624919A (zh) * 2022-11-08 2023-01-20 中国科学院过程工程研究所 一种浆态床反应器及其应用

Also Published As

Publication number Publication date
CN119236804A (zh) 2025-01-03
CN119236804B (zh) 2026-01-06
TW202502437A (zh) 2025-01-16

Similar Documents

Publication Publication Date Title
CN101480595B (zh) 一种带针型翅片列管束的浆态鼓泡塔反应器
CN104801240B (zh) 一种板式换热反应器
CN1132735A (zh) 丙烯催化气相氧化制丙烯醛
CN103990420A (zh) 列管式固定床反应器及其应用
JP5877067B2 (ja) 気相反応方法
CN102675495B (zh) 烯烃聚合反应器和聚合方法
CN208049900U (zh) 一种列管式固定床反应器
CN104128133A (zh) 后掠式高效热板导流整流多相反应釜
JP5691151B2 (ja) 熱交換型反応器を用いた反応方法
TWI922982B (zh) 包含液體分佈裝置的固定床反應器和使用這種反應器進行多相催化反應的方法
TW202502437A (zh) 包含液體分佈裝置的固定床反應器和使用這種反應器進行多相催化反應的方法
CN121222341A (zh) 包含液体分布装置的固定床反应器及使用这种反应器进行多相催化反应的方法
CN211754821U (zh) 一种自取热式固定床反应器及系统
CN121222342A (zh) 包含液体分布装置的固定床反应器以及使用这种反应器进行多相催化反应的方法
CN105776141B (zh) 一种氯化氢催化氧化制氯气新型固定床反应器
CN204724141U (zh) 一种板式换热反应器
CN112705114B (zh) 一种换热式多相反应器及其应用方法和轻汽油醚化方法
CN103285782B (zh) 一种催化剂下料管
CN107107012A (zh) 用于固定床脱氢反应器的工程化惰性介质
CN113967452B (zh) 一种适用于多品种纳米粉体的组装型超临界水热合成平台
CN202752008U (zh) 一种气相加氢反应器
CN111569787A (zh) 一种列管式固定床反应器及其在烯烃环氧化反应中的应用
CN213254347U (zh) 一种带有导流的列管式反应器
WO2003068379A2 (en) Apparatus for heterogeneous catalysed reactions
JP7698564B2 (ja) 大規模ｄｍｏ反応に用いられる横型マルチフロープレート式反応装置

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 24835273

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE