CN110961060A

CN110961060A - Micro-channel reactor

Info

Publication number: CN110961060A
Application number: CN201811160619.3A
Authority: CN
Inventors: 侯朝鹏; 徐润; 孙霞; 夏国富; 唐晓津; 阎振楠; 张哲民; 胡志海
Original assignee: Sinopec Research Institute of Petroleum Processing; China Petroleum and Chemical Corp
Current assignee: Sinopec Research Institute of Petroleum Processing; China Petroleum and Chemical Corp
Priority date: 2018-09-30
Filing date: 2018-09-30
Publication date: 2020-04-07

Abstract

The present disclosure relates to a microchannel reactor, comprising: the shell has feed inlet, discharge gate, cooling fluid import and cooling fluid export, and microchannel reaction unit is located inside the shell, and microchannel reaction unit includes microchannel reactor wall, and microchannel reactor wall includes: a stainless steel base layer having a first side forming a reaction channel; a rough processing layer processed on the first side surface; and the catalyst carrier layer is formed on the rough processing layer, the feed inlet is communicated with the discharge outlet through a reaction channel, a cooling channel arranged along the microchannel reaction unit is also arranged in the shell, and the cooling fluid inlet is communicated with the cooling fluid outlet through the cooling channel. Like this, the catalyst carrier layer is adhered to through the rough machining layer of processing on the stainless steel base layer, and the rough machining layer can effectively promote the area of adhering to of catalyst carrier layer through the rough surface, improves the adhesive force between catalyst carrier layer and the stainless steel base layer simultaneously, is favorable to the reaction to go on smoothly.

Description

Micro-channel reactor

Technical Field

The disclosure relates to the technical field of petroleum refining and chemical reaction instruments, in particular to a micro-channel reactor.

Background

In recent years, microchannel reactors have become a focus of research in the field of new reactors. Compared with the chemical reaction carried out in the conventional reaction vessel, the microchannel reactor has the advantages of less catalyst consumption, high catalyst efficiency, short diffusion data rate, quick heat transfer and the like, thereby achieving the purpose of accelerating the catalytic reaction.

In a common filling type fixed bed microchannel reactor, due to the non-uniformity and randomness of catalyst particles accumulated in the reactor, a catalyst bed layer has a large pressure drop or reactant bias flow is caused, and the utilization of the catalyst and the bed layer is not facilitated; meanwhile, the gap between the catalyst and the wall of the reactor can increase the resistance of the bed layer to heat transfer outwards. For this reason, the research on the coated microchannel reactor is increasing. The coated microchannel reactor accelerates the catalytic reaction mainly by coating a catalyst carrier on a base material, and the commonly used base materials are FeCrAl alloy and stainless steel. FeCrAl alloy has the disadvantages of low mechanical strength, easy corrosion and high price. The stainless steel has the advantages of good heat-conducting property, strong shock resistance, good economy and the like, but the binding force between the catalyst carrier and the stainless steel is not high, so that the coated catalyst carrier is difficult to be attached to the stainless steel, and the reaction efficiency is further influenced.

Disclosure of Invention

The purpose of the present disclosure is to provide a microchannel reactor, which can effectively improve the adhesion force of a catalyst carrier and stainless steel, so that a catalytic reaction can be smoothly performed.

In order to achieve the above object, the present disclosure provides a microchannel reactor, comprising: a housing having a feed inlet, a discharge outlet, a cooling fluid inlet, and a cooling fluid outlet, a microchannel reactor unit positioned within the housing, the microchannel reactor unit comprising a microchannel reactor wall, the microchannel reactor wall comprising: a stainless steel base layer having a first side forming a reaction channel; a rough machining layer machined on the first side surface; and the catalyst carrier layer is formed on the rough processing layer, the feed inlet is communicated with the discharge outlet through the reaction channel, the shell is also internally provided with a cooling channel arranged along the micro-channel reaction unit, and the cooling fluid inlet is communicated with the cooling fluid outlet through the cooling channel.

Optionally, the rough processed layer is a rough layer formed by a sand blasting process.

Optionally, the blasting materials selected by the sand blasting processing technology comprise quartz sand, copper ore sand, carborundum, iron sand or Hainan sand, and the particle size range of the blasting materials is 50-600 meshes.

Optionally, the roughness of the rough machining layer is 1 μm to 100 μm.

Optionally, the catalyst supporting layer is an alumina layer including an alumetized layer formed on the rough processed layer.

Optionally, the aluminum oxide layer further comprises an aluminum oxide sol layer coated on the aluminized layer.

Optionally, the stainless steel substrate is a plate-shaped structure, the first side surface is formed with a plurality of first channel grooves extending in the same direction, and the number of the reactor walls is two, and adjacent reactor walls are butted against each other to form the reaction channels.

Optionally, in adjacent microchannel reaction units, the cooling channel is formed between the second sides of the stainless steel substrate layers, and the cooling fluid inlet and the cooling fluid outlet communicate through the cooling channel.

Optionally, the second side surface is formed with second channel grooves, the first channel grooves and the second channel grooves are arranged perpendicular to each other, and in adjacent microchannel reaction units, the second side surfaces of the stainless steel substrate layers are butted so that the corresponding second channel grooves form the cooling channels.

Optionally, the housing includes a cylindrical body accommodating the microchannel reaction unit, two ends of the cylindrical body are respectively connected with a flange, and a connecting pipe forming the cooling fluid inlet and the cooling fluid outlet is disposed on a side wall of the cylindrical body.

Through the technical scheme, the microchannel reactor provided by the disclosure has the reactor wall formed by jointly constructing the stainless steel base layer, the rough machining layer and the catalyst carrier layer, the catalyst carrier layer is attached to the rough machining layer on the stainless steel base layer through machining, the rough machining layer can effectively improve the attachment area of the catalyst carrier through the rough surface instead of being coated on the stainless steel base layer through a coating mode, meanwhile, the adhesive force between the catalyst carrier layer and the stainless steel base layer is improved, and the smooth reaction is facilitated.

Additional features and advantages of the disclosure will be set forth in the detailed description which follows.

Drawings

The accompanying drawings, which are included to provide a further understanding of the disclosure and are incorporated in and constitute a part of this specification, illustrate embodiments of the disclosure and together with the description serve to explain the disclosure without limiting the disclosure. In the drawings:

FIG. 1 is a schematic diagram of a microchannel reactor provided in an exemplary embodiment of the present disclosure;

FIG. 2 is a front view of FIG. 1;

FIG. 3 is a schematic structural view of a microchannel reaction unit in the microchannel reactor shown in FIG. 1;

FIG. 4 is a schematic diagram of the configuration of the reactor wall in the microchannel reaction unit shown in FIG. 3;

FIG. 5 is a cross-sectional view of the reactor wall shown in FIG. 4;

FIG. 6 is a schematic structural view of reaction channels formed by abutting first sides of two adjacent reactor walls;

FIG. 7 is a schematic view showing the structure of cooling channels formed by abutting the second sides of two adjacent reactor walls.

Description of the reference numerals

11 first channel groove 12 second channel groove

20 tubular main body 21 connecting pipe

30 flange 101 stainless steel base coat

102 rough finish layer 103 catalyst support layer

Detailed Description

The following detailed description of specific embodiments of the present disclosure is provided in connection with the accompanying drawings. It should be understood that the detailed description and specific examples, while indicating the present disclosure, are given by way of illustration and explanation only, not limitation.

In the present disclosure, unless otherwise specified, the use of directional words such as "upper" and "lower" is defined based on the direction of the drawing shown in fig. 2, and "inner" and "outer" refer to the inner and outer of the respective component profiles. Furthermore, the terms "first," "second," and the like, as used in this disclosure, are intended to distinguish one element from another, and not necessarily for order or importance. When the following description refers to the accompanying drawings, like numbers in different drawings represent the same or similar elements unless otherwise indicated.

Referring to fig. 1-7, the present disclosure provides a microchannel reactor comprising a housing and a microchannel reaction unit. The shell is provided with a feeding hole, a discharging hole, a cooling fluid inlet and a cooling fluid outlet; the microchannel reactor unit is located inside the housing and includes a microchannel reactor wall. The microchannel reactor wall comprises a stainless steel base layer 101, a roughened layer 102, and a catalyst support layer 103, the stainless steel base layer 101 having a first side on which reaction channels are formed, the roughened layer 102 being machined on the first side, and the catalyst support layer 103 being formed on the roughened layer 102. The feed inlet and the discharge outlet are communicated through the reaction channel, in addition, a cooling channel arranged along the microchannel reaction unit is also arranged in the shell, and the cooling fluid inlet and the cooling fluid outlet are communicated through the cooling channel.

Thus, when the microchannel reactor provided by the present disclosure is used for chemical reaction, reaction raw materials enter the reaction channel from the feed inlet, and the chemical reaction is carried out under the catalytic action of the catalyst attached to the catalyst carrier layer 103 in the reaction channel formed by the reactor wall, the final product is discharged from the discharge outlet, and the cooling channel can cool the reaction channel through the internal fluid. Wherein, a reaction channel is formed on the first side surface of the stainless steel substrate layer 101 of the reactor wall, and a rough processing layer 102 and a catalyst carrier layer 103 are sequentially formed on the first side surface, namely the catalyst carrier layer 103 is the innermost surface of the reaction channel, so that the catalyst component passing through the catalyst carrier layer directly contacts with the raw material entering the reaction channel and carries out catalytic reaction.

The reactor wall is used as the self-composing structure of the reactor, and the internal material organization of the reactor comprises a stainless steel base layer 101, a rough processing layer 102 and a catalyst carrier layer 103. The catalyst supporting layer 103, which is an integral part directly constituting the reactor wall, is present as it is when the reactor wall is formed, rather than being subsequently coated on the stainless steel substrate of the reaction channel in the form of a coating film, so that the adhesion and thermal stability between the catalyst supporting layer 103 and the stainless steel substrate layer 101 can be improved. That is, the conventional reactor wall is made of pure stainless steel metal, and a catalyst needs to be additionally coated on a stainless steel substrate during subsequent chemical reaction, but the reactor wall provided by the present disclosure has a rough processing layer 102 and a catalyst carrier layer 103 formed on a stainless steel substrate layer 101 in a certain manner, and the structure configuration of the reactor wall is obviously different from that of the conventional reactor wall, such structure can effectively improve the adhesion area and adhesion between the catalyst carrier layer 103 and the stainless steel substrate layer 101, and the catalyst carrier layer 103 is directly formed on the reactor wall, and can also enable heat generated by exothermic reaction to be rapidly conducted out or heat required by endothermic reaction to be rapidly conducted in, thereby facilitating smooth reaction.

Specifically, the rough processed layer 102 may be a rough layer formed on a stainless steel substrate layer by various processing means, for example, in this embodiment, the rough layer may be formed by a sand blasting process, wherein the blasting material selected by the sand blasting process may include quartz sand, copper ore sand, carborundum, iron sand, Hainan sand, or the like, and the grain size of the blasting material may be in a range of 50 mesh to 600 mesh. Thus, a rough layer can be formed on the stainless steel base layer after the sand blasting process. The sand blasting process adopts compressed air as power to form a high-speed spray beam by spraying spray materials on the surface of a workpiece to be processed, so that the outer surface of the workpiece is changed, and the surface of the workpiece can obtain certain cleanliness and different roughness due to the impact and cutting action of the spray materials on the surface of the workpiece, thereby improving the mechanical property and the surface property of the surface of the workpiece and improving the fatigue resistance of the workpiece. Corresponding to the microchannel reactor wall in the present disclosure, the spray is sprayed on the first side of the stainless steel substrate layer 101 by a sand blasting process, which can increase the adhesion between the stainless steel substrate layer 101 and the catalyst support layer 103 through the formed rough layer, prolong the durability of the catalyst support layer 103, and facilitate the wetting and leveling of the catalyst support layer 103.

In other embodiments, the rough processed layer 102 may also be formed on the stainless steel base layer 101 by other processing means such as chemical etching, laser etching, etc., thereby forming a regular or irregular rough processed surface to improve adhesion and an adhesion area to the catalyst support layer 103. Also, in some embodiments of the present disclosure, the roughness of the rough processed layer may be formed to be 1 μm to 100 μm. Wherein roughness is also referred to as surface roughness, which may be expressed as Rz, in some embodiments, the test method is: before testing, the sample is ultrasonically cleaned for 10min by acetone and then dried by oilless compressed air. As measured by a TR240 Portable surface roughness tester, Rz is the arithmetic average of the 10 peak-to-valley heights (5 peaks plus 5 valleys) of the substrate surface, the distance of the sample point may be 0.8mm, and each sample may be measured 10 times and averaged.

Further, the catalyst supporting layer 103 may be an alumina layer including an alumetized layer formed on a rough processed layer. The aluminizing layer is prepared through the corrosion aluminizing process, so that the aluminizing agent can be fully contacted with the surface of the stainless steel substrate layer 101, and the alumina layer obtained after aluminizing and oxidation is more uniform and tougher in strength.

Further, the alumina layer may further include an alumina sol layer coated on the alumetized layer. The alumina carrier prepared by the sol-gel method has uniform crystal grains after long-term aging, good growth after roasting, higher porosity, larger specific surface area and proper pore diameter, thus having good heat-conducting property, thermal stability and higher economy. The catalyst supporting layer 103 thus formed may, in some embodiments, support ruthenium, which is an FT synthesis catalyst component, by an impregnation method, so that a ruthenium-based FT synthesis catalyst having excellent FT synthesis performance can be obtained. Wherein the specific catalyst components may vary from reaction to reaction, the disclosure is not limited thereto.

Referring to fig. 4 to 6, the stainless steel substrate 101 may be specifically configured as a plate-shaped structure, a plurality of first channel grooves 11 may be formed on a first side surface of the substrate, the plurality of first channel grooves 11 are arranged at intervals, the plurality of first channel grooves 11 extend in the same direction, two reactor walls may be provided, and two adjacent reactor walls are butted against each other so that the corresponding first channel grooves 11 form reaction channels. In the embodiment of the present disclosure, the stainless steel substrate 101 may be a stainless steel plate, the first channel grooves 11 on the stainless steel plate are formed as reaction channels of the microchannel reactor, the rough processed layer 102 and the catalyst support layer 103 may be previously provided on the stainless steel plate by the following method to form reactor walls, and each adjacent two reactor walls may be fixed together by means of, for example, brazing, high temperature diffusion welding, or the like to form a plurality of reaction channels in the same plane. The reaction channels are linear channels with the same extending direction as the stainless steel plates, and the number, the size and the spacing of the channels can be set according to the reaction scale and the heat release. In other embodiments, the reaction channels may be formed in other configurations, for example, the reaction channels may be formed directly from a tubular substrate, avoiding butt joints.

Further, as shown in fig. 3, in the adjacent microchannel reaction unit, a cooling channel is formed between the second sides of the stainless steel substrate layers 101, and the cooling fluid inlet and the cooling fluid outlet are communicated through the cooling channel. The first side and the second side are two opposite end faces of the stainless steel substrate layer 101, so that both sides of each reactor wall are provided with the cooling channel and the reaction channel, and the cooling channel can rapidly cool the reaction channel.

Still further, referring to fig. 4 and 7, the second side of the reactor wall may be formed with second channel grooves 12, the first channel grooves 11 and the second channel grooves 12 are disposed perpendicular to each other, and the second sides of the stainless steel substrate layers 101 are butted in adjacent microchannel reaction units such that the corresponding second channel grooves 12 form cooling channels. The second side surfaces of the adjacent stainless steel substrate layers 101 can also be fixed together in a welding mode and the like, so that a plurality of reactor walls are sequentially butted to form a micro-channel reaction unit, and meanwhile, the reaction channels and the cooling channels are arranged in a three-dimensional staggered mode, the structure is simple, the manufacturing is convenient, the reaction channels and the cooling channels can be simultaneously integrated on the reactor walls, and the space utilization rate of the micro-channel reactor is improved.

In addition, referring to fig. 1 and 2, the housing of the microchannel reactor may include a cylindrical body 20 accommodating the microchannel reaction unit, flanges 30 may be respectively connected to both ends of the cylindrical body 20 to connect the feed port and the discharge port of the microchannel reactor to corresponding devices through the flanges 30, and the cylindrical body 20 and the flanges 30 may be fixed by welding or the like. Wherein, a connection pipe 21 forming a cooling fluid inlet and a cooling fluid outlet may be provided on a sidewall of the cylindrical body 20 to deliver the cooling fluid into the cooling flow passage through the connection pipe 21.

Referring to fig. 2, the microchannel reactor unit may include a plurality of plate-shaped reactor walls which are sequentially butted when assembled, and the uppermost and lowermost reactor walls may be formed with the first passage grooves 11 only on a first side surface, and a second side surface may be fixedly connected to the upper and lower cover plates, respectively. The upper cover plate and the lower cover plate may be of plate structures having the same length and width as the reactor wall, and the other end surfaces of the upper cover plate and the lower cover plate are fixedly connected with the inner wall of the cylindrical main body 20.

The present disclosure will be described in detail with reference to the following specific examples of the steps and processes for forming the rough finish layer 102 and the catalyst supporting layer 103 on the stainless steel base layer 101 of the reactor wall in this order, but the present disclosure is not limited to this example. In the following steps, the initial stainless steel sample may be considered the stainless steel base layer 101 of the reactor wall in this disclosure.

The first step is as follows: and (4) polishing the stainless steel sample by using sand paper to remove foreign matters on the surface. The stainless steel may be 316, 304, etc., and the sand paper for polishing may be 100-600 mesh, preferably 150-400 mesh.

The second step is that: and cleaning and removing oil by using acetone. And ultrasonically oscillating the polished stainless steel sample in acetone for 10-120 min, preferably for 30-60 min. After being cleaned by acetone, the stainless steel sample is dried in the air and is dried, and the drying temperature is 50-300 ℃.

The third step: the surface of the stainless steel sample was sandblasted. The spraying material can be selected from quartz sand, copper ore sand, carborundum, iron sand, Hainan sand and the like, preferably quartz sand, and the granularity range is 50-600 meshes, preferably 100-300 meshes. The pressure of the spray material sprayed to the surface of the sample under the pressure of about 0.7MPa is 0.2MPa to 3.0MPa, preferably 0.3MPa to 1.5MPa, the angle between the nozzle and the normal line of the surface of the sample is 5 degrees to 45 degrees, preferably 10 degrees to 15 degrees, and the distance from the nozzle to the sample is 5mm to 150mm, preferably 10mm to 100 mm.

The fourth step: and (3) loading the stainless steel sample into a charging bucket, filling and compacting the sample with the buried powder after the sample is loaded, and finally sealing the sample with the refractory mortar.

Wherein, the buried powder is an aluminizing agent prepared from 1-15% of Al powder, 1-15% of Fe powder, 1-10% of Si powder, 1-8% of NH4Cl and the balance of alumina by mass percentage. In the above alumetizing agent, the mass fraction of Al powder is preferably 5% to 10%, the mass fraction of Fe powder is preferably 5% to 10%, the mass fraction of silicon powder is preferably 3% to 6%, the mass fraction of NH4Cl powder is preferably 2% to 4%, and the balance is alumina powder.

And after the refractory mortar is dried, heating the charging bucket in a heating furnace to raise the temperature. The roasting temperature is 600-1200 ℃, and preferably 750-1000 ℃; the heating rate is 0.2 ℃/min to 5.0 ℃/min, preferably 0.5 ℃/min to 2.0 ℃/min. And cooling the sample along with the furnace after heat preservation for a certain time. The heat preservation time is 30min to 1200min, preferably 60min to 180 min. The cooling is preferably natural cooling.

The fifth step: and taking out the sample, washing the sample by using distilled water, washing off the embedded material powder attached to the surface, and then ultrasonically oscillating the sample in acetone for 10 to 120min, preferably 30 to 60 min. After washing with acetone, the stainless steel sample was air dried.

And a sixth step: placing the sample after aluminizing in a roasting furnace for roasting and oxidizing, wherein the roasting temperature is 400-900 ℃, and preferably 500-700 ℃; the heating rate is 0.2 ℃/min to 5.0 ℃/min, preferably 0.5 ℃/min to 3.0 ℃/min.

The seventh step: and (3) preparing alumina sol.

a. Preparing nitric acid with the mass fraction of 0.1-0.8%, preferably 0.2-0.5%; mixing nitric acid and pseudo-boehmite according to a molar ratio of H +/Al3+ (0.05-0.30), preferably H +/Al3+ (0.10-0.20); stirring for 0.5 to 5 hours, preferably 1 to 3 hours at 50 to 90 ℃; and then reacting and aging for 6-48 h, preferably 12-36 h to obtain the aged alumina sol slurry.

b. Preparing polyethylene glycol solution. Adding pore-expanding agent and adhesive, wherein the pore-expanding agent and the adhesive are preferably polyethylene glycol. Preparing a polyethylene glycol solution, wherein the mass fraction of polyethylene glycol is 5-40%.

c. And mixing the aged alumina sol slurry and the polyethylene glycol solution, and stirring to obtain uniform slurry.

Eighth step: and (4) coating alumina sol. Coating is carried out according to a dropping dipping method or a dipping pulling method. The dropping dipping method is that the alumina sol slurry is dropped on a sample, and the wettability of the alumina layer is enhanced by the generation of the stainless steel surface, so that the alumina sol slurry is spread on the surface of the sample; the dip-coating method is to dip a sample in alumina sol slurry, take out the sample, and drain the sample. The drop-wise impregnation method is preferred.

The ninth step: after coating, fully drying at room temperature, and then drying at 50-300 ℃, preferably 100-150 ℃; the time is 0.5h to 10h, preferably 2h to 4 h; the heating rate is 0.05 ℃/min-5.0 ℃/min, preferably 0.1 ℃/min-3.0 ℃/min.

The tenth step: the dried coating sample piece can be put into a muffle furnace for roasting, the roasting temperature is 450-900 ℃, the heating rate is 0.2-5.0 ℃/min, and the preferable temperature is 0.5-3.0 ℃/min. The time is 0.5h to 10h, preferably 2h to 4 h; naturally cooling to room temperature and taking out the sample.

The eleventh step: the loading can be increased by repeating the coating as many times as necessary, and is preferably 1 to 5 times.

In the above steps, the third step is to provide a rough finish layer on the first side of the stainless steel base layer 101, the fourth to sixth steps are to provide an alumetized layer on the rough finish layer, and the seventh step is followed by providing an alumina sol layer on the alumetized layer. The method for forming the rough processed layer and the catalyst supporting layer 103 is a conventional method well known to those skilled in the art, and the specific process parameter values may be adjusted and set according to the implementation.

In the reactor wall formed by the method, the stainless steel substrate layer 101 and the catalyst carrier layer 103 are effectively adhered together through the rough processing layer 102, so that the adhesion force and the adhesion area of the catalyst carrier on the stainless steel are improved, and the chemical reaction is smoothly carried out. This advantageous effect of the reactor wall can be further demonstrated by the following comparative examples and examples.

Comparative example 1

First, a test piece (3.0mmX3.0mm) was processed. After the surface is polished by 500-mesh sand paper, the surface is ultrasonically vibrated for 30min in an acetone solution to remove dirt on the surface. The aluminizing agent is prepared from 7% of Al powder, 7% of Fe powder, 3% of Si powder, 3% of NH4Cl and the balance of aluminum oxide. Mixing the aluminizing agent and the test piece together, and roasting at 900 ℃ for 120min to prepare the stainless steel with the surface rich in aluminum. And cleaning the surface of the test piece after aluminizing is finished, then ultrasonically oscillating for 45min in an acetone solution to remove surface dirt, heating to 600 ℃ at the heating rate of 2.0 ℃/min, and roasting for 120min to prepare the stainless steel sheet with the surface rich in the alumina layer. Mixing nitric acid and pseudo-boehmite according to a molar ratio H +/Al3+ (0.10), stirring at 80 ℃ for 1.0H, and reacting and aging for 12H to obtain aged alumina sol; mixing the sol and 20% of polyethylene glycol, stirring to obtain uniform slurry, and coating by dripping dipping method. After coating was complete, drying was carried out at room temperature for 3h and then at 120 ℃ for 3h with a heating rate of 0.5 ℃/min. And after drying, placing the coated piece into a muffle furnace for roasting, wherein the roasting temperature is 600 ℃, the heating rate is 0.8 ℃/min, the time is 3h, and naturally cooling to room temperature to take out the sample. Denoted as DB 01.

Example 1

First, a test piece (3.0mmX3.0mm) was processed. After the surface is polished by 500-mesh sand paper, the surface is ultrasonically vibrated for 30min in an acetone solution to remove dirt on the surface. The surface of the stainless steel sample was subjected to sand blasting to form a rough processed layer. The material spraying can be quartz sand, and the particle size range is as follows: 200 meshes to 300 meshes. The aluminizing agent is prepared from 7% of Al powder, 7% of Fe powder, 3% of Si powder, 3% of NH4Cl and the balance of aluminum oxide. Mixing the aluminizing agent and the test piece together, and roasting at 900 ℃ for 120min to prepare the stainless steel with the surface rich in aluminum. And cleaning the surface of the test piece after aluminizing is finished, then ultrasonically oscillating for 45min in an acetone solution to remove surface dirt, heating to 600 ℃ at the heating rate of 2.0 ℃/min, and roasting for 120min to prepare the stainless steel sheet with the surface rich in the alumina layer. Mixing nitric acid and pseudo-boehmite according to a molar ratio H +/Al3+ (0.10), stirring at 80 ℃ for 1.0H, and reacting and aging for 12H to obtain aged alumina sol; mixing the sol and 20% of polyethylene glycol, stirring to obtain uniform slurry, and coating by dripping dipping method. After coating was complete, drying was carried out at room temperature for 3h and then at 120 ℃ for 3h with a heating rate of 0.5 ℃/min. And after drying, placing the coated piece into a muffle furnace for roasting, wherein the roasting temperature is 600 ℃, the heating rate is 0.8 ℃/min, the time is 3h, and naturally cooling to room temperature to take out the sample. Denoted as a 01.

Example 2

First, a test piece (3.0mmX3.0mm) was processed. After the surface is polished by 400-mesh sand paper, the surface is ultrasonically vibrated for 30min in an acetone solution to remove dirt on the surface. The surface of the stainless steel sample was subjected to sand blasting to form a rough processed layer. The material spraying can be quartz sand, and the particle size range is as follows: 200 meshes to 300 meshes. The aluminizing agent is prepared from 8% of Al powder, 5% of Fe powder, 3% of NH4Cl and the balance of alumina. Mixing the aluminizing agent and the test piece together, and roasting at 850 ℃ for 120min to prepare the stainless steel with the surface rich in aluminum. And cleaning the surface of the test piece after aluminizing is finished, then ultrasonically oscillating for 45min in an acetone solution to remove surface dirt, heating to 500 ℃ at the heating rate of 2.0 ℃/min, and roasting for 120min to prepare the stainless steel sheet with the surface rich in alumina. Mixing nitric acid and pseudo-boehmite according to a molar ratio H +/Al3 +/0.12, stirring at 70 ℃ for 1.0H, and reacting and aging for 12H to obtain aged alumina sol; mixing the sol and 20% of polyethylene glycol, stirring to obtain uniform slurry, and coating by dripping dipping method. After coating was complete, drying was carried out at room temperature for 3h and then at 120 ℃ for 3h with a heating rate of 0.5 ℃/min. And after drying, placing the coated piece into a muffle furnace for roasting, wherein the roasting temperature is 700 ℃, the heating rate is 0.8 ℃/min, the time is 3h, and naturally cooling to room temperature to take out the sample. Denoted as a 02.

Example 3

First, a test piece (3.0mmX3.0mm) was processed. After the surface is polished by 400-mesh sand paper, the surface is ultrasonically vibrated for 30min in an acetone solution to remove dirt on the surface. The surface of the stainless steel sample was subjected to sand blasting to form a rough processed layer. The material spraying can be quartz sand, and the particle size range is as follows: 200 meshes to 300 meshes. The aluminizing agent is prepared from 9% of Al powder, 4% of Fe powder, 4% of NH4Cl and the balance of alumina. Mixing the aluminizing agent and the test piece together, and roasting at 900 ℃ for 120min to prepare the stainless steel with the surface rich in aluminum. And cleaning the surface of the test piece after aluminizing is finished, then ultrasonically oscillating for 45min in an acetone solution to remove surface dirt, heating to 500 ℃ at the heating rate of 2.0 ℃/min, and roasting for 120min to prepare the stainless steel sheet with the surface rich in alumina. Mixing nitric acid and pseudo-boehmite according to a molar ratio H +/Al3+ (0.15), stirring at 70 ℃ for 1.0H, and reacting and aging for 24H to obtain an aged alumina sol; mixing the sol and 25% of polyethylene glycol, stirring to obtain uniform slurry, and coating by dripping dipping method. After coating was complete, drying was carried out at room temperature for 3h and then at 120 ℃ for 3h with a heating rate of 0.5 ℃/min. And after drying, placing the coated piece into a muffle furnace for roasting, wherein the roasting temperature is 800 ℃, the heating rate is 0.8 ℃/min, the time is 3h, and naturally cooling to room temperature to take out the sample. Denoted as a 03.

The mass of the sample was measured before the application of the alumina sol and after the baking treatment of the applied alumina sol, respectively, and the weight gain of the sample was calculated. Ultrasonic oscillation is carried out in distilled water for 15 min. Then dried at 300 ℃. The falling rate of the catalyst carrier alumina was measured. The following values were obtained:

sample number	Weight gain/g of sample	Loss rate/%)
			DB01	0.112	9.4％
A01	0.124	5.2％
			A02	0.131	4.6％
A03	0.123	4.7％

As is clear from comparison between DB01 and a01, by forming the roughened layer 102 and the catalyst support layer 103 in this order on the stainless steel base layer 101, the amount of adhesion of the catalyst support layer 103 to the stainless steel base layer 101 is increased, and it is not easily peeled off, that is, the adhesion between the catalyst support layer 103 and the stainless steel base layer 101 is improved. Comparing a01, a02, a03, it can be seen that the adhesion of the catalyst support layer 103 to the stainless steel base layer 101 can be further improved as well during the formation of the catalyst support layer 103 using process parameter values within the preferred ranges provided by the present disclosure.

In addition, active metal components can be continuously loaded on the catalyst supporting layer 103 of the reactor wall to prepare synthetic catalysts applied to different chemical reactions, so that the reactions are more efficient. The following description is given by way of example, but the scope of the present disclosure is not limited thereto, and other modifications are also within the scope of the present disclosure without departing from the central concept of the present disclosure.

The fischer-tropsch synthesis reaction (FT reaction) is a strongly exothermic gas-solid-liquid heterogeneous reaction system, in which the catalyst particle diameter is typically several millimeters, and therefore, the influence of diffusion control on the catalytic activity is difficult to avoid. The heavy paraffin obtained by Fischer-Tropsch synthesis is usually loaded on the surface of the catalyst in the form of liquid, steam sol or slurry, and reacts on the reactant H₂And the diffusion of CO inside the catalyst particles. During the internal diffusion of the reactants, H₂Has a diffusion speed higher than that of CO, and the diffusion limiting effect of CO in the catalyst particles is obviously stronger than that of H₂. Because the particle sizes of the particles are different, the difference of CO concentration gradient in the particles is caused, the combination of CO and the active center position of the metal is influenced, the H/C ratio adsorbed on the active center is increased, the carbon chain growth probability is reduced, and the selectivity of C5+ is reduced. One of the effective ways to solve this problem is to improve the FT synthesisThe FT synthesis catalyst is loaded on a metal wall in a catalyst loading mode, and heat generated by reaction can be transferred out by a metal conductor, so that the problem of strong heat release is solved; meanwhile, the thin-layer catalyst loaded on the metal wall is also beneficial to improving the selectivity of C5+ hydrocarbons due to short diffusion distance, and the smooth diffusion can also enable the reaction to be more efficient.

In one embodiment, an alumina-coated Co-based FT synthesis catalyst layer may be formed by supporting an active metal component Co on the above-described catalyst supporting layer 103, by continuing the following steps after the above-described eleventh step.

The twelfth step: active metal Co is loaded.

a. The content of the metal component Co is preferably 5 to 80% by weight, more preferably 10 to 70% by weight, and even more preferably 20 to 60% by weight, in terms of oxide, based on the catalyst.

b. The compound containing the active metal component Co is selected from one or more of soluble compounds of the compound, and can be one or more of cobalt nitrate, cobalt acetate, cobalt carbonate, cobalt chloride and soluble complex.

c. The salts of the active component Co of the catalyst may be introduced into the catalyst support by conventional methods, preferably by impregnation, for example by preparing a solution of the compound containing the active metal component, followed by impregnation by dipping or spraying, drying and calcination.

d. The auxiliary agent in the catalyst is selected from one or more auxiliary agent components of Cu, Mo, Ta, W, Ru, Zr, Ti, REO, Re, Hf, La, Ce, Mn, V and noble metal, wherein the auxiliary agent is preferably selected from one or more of W, Zr, Re, Ru and Ce, and the noble metal is selected from one or more of Pt, Pd, Rh and Ir and is an auxiliary agent component which is known in the field of FT synthesis and is commonly used for a Fischer-Tropsch synthesis catalyst. The catalyst support layer provided according to the present disclosure may optionally contain one or more selected from the above-described auxiliary components, as necessary.

e. The content of the promoter component, other than the noble metal, is preferably 30% by weight or less, more preferably 20% by weight or less, and still more preferably 15% by weight or less, in terms of oxide and based on the catalyst.

f. When the promoter component is selected from noble metals, the content of the promoter component is preferably 10% by weight or less, more preferably 1% by weight or less, in terms of metal and based on the catalyst. The adjuvant component may be introduced before, after or simultaneously with the loading of the active metal component, with impregnation prior to or simultaneously with the loading of the metal component being preferred.

The thirteenth step: the catalyst is dried at a temperature of 50 ℃ to 200 ℃, preferably 100 ℃ to 180 ℃, and more preferably 120 ℃ to 150 ℃.

The fourteenth step is that: and roasting the catalyst, wherein the roasting temperature can be 200-600 ℃, preferably 250-600 ℃, and the roasting time is 1-12 hours, preferably 2-6 hours.

The fifteenth step: the loading amount of the active component Co can be increased by repeating the impregnation as many times as necessary, and is preferably 1 to 5 times.

The reactor wall having the alumina-coated Co-based FT synthesis catalyst layer formed as described above was assembled into a reactor to be applied to the FT synthesis reaction under the conventional reaction conditions for the FT synthesis reaction. For example, the catalyst is first reduced according to conventional methods in the art, suitable reducing conditions include: the reduction temperature is 100 ℃ to 800 ℃, preferably 200 ℃ to 600 ℃, and more preferably 300 ℃ to 450 ℃; the reduction time is 0.5-72 h, preferably 1-24 h, and more preferably 2-8 h, the reduction can be carried out in pure hydrogen, or in a mixed gas of hydrogen and an inert gas, such as a mixed gas of hydrogen and nitrogen and/or argon, and the hydrogen pressure is 0.1-4 MPa, preferably 0.1-2 MPa.

Further, the conditions for contacting the mixture of carbon monoxide and hydrogen with the catalyst for reaction may be: the temperature is preferably 160-300 ℃, more preferably 190-250 ℃, the pressure is preferably 1-8 MPa, more preferably 1-5MPa, the molar ratio of hydrogen to carbon monoxide is 0.4-2.5, preferably 1.5-2.5, more preferably 1.8-2.2, and the space-time rate of the gas is 2000-300000 h < -1 >, preferably 4000-200000 h < -1 >.

The present disclosure will be described below with reference to comparative examples and examples to explain the advantageous effects of the reactor wall formed with the alumina-coated Co-based FT synthesis catalyst layer.

Specifically, the carriers a01, a02 and a03 and the comparative carrier DB01 obtained in the above comparative examples and examples were saturated with a mixed solution containing cobalt nitrate and an auxiliary agent, followed by drying and calcination to obtain catalysts C01, C02 and C03, and comparative catalyst CDB 01. Wherein the drying temperature is 120 ℃, the drying time is 3 hours, the roasting temperature is 350 ℃, and the roasting time is 3 hours. The amount of cobalt nitrate used is such that the cobalt oxide content in the final catalyst is 45-50 wt% and the precious metal promoter content is about 0.1 wt% Pt.

The FT synthesis reaction performance of catalysts C01, C02 and C03, and comparative catalyst CDB01 were evaluated in a fixed bed reactor, respectively. Stainless steel sheets carrying active components are mounted in slots inside the reactor. The raw material gas composition is as follows: H2/CO/N2 ═ 64%/32%/4% (volume in% parts).

Catalyst reduction reaction conditions: the pressure is normal pressure, the heating rate is 5 ℃/min, the air speed of hydrogen is 2000h-1, the reduction temperature is 400 ℃, and the reduction time is 5 h.

Reaction conditions are as follows: the pressure is 3.0MPa, the temperature is 220 ℃, and the space velocity of the synthesis gas (raw material gas) is 10000 h-1.

After 24 hours the reaction was run, gas samples were taken for chromatography, wherein the CO conversion, methane selectivity and C5+ hydrocarbon selectivity are listed in the table below.

As can be seen from the above table, when the reactor wall provided by the present disclosure is used for chemical reaction, the FT synthesis catalyst layer has the characteristics of high activity, high C5+ hydrocarbon selectivity, and low methane selectivity, which is superior to the comparative example in the prior art.

In other embodiments, an active metal component Ru may be supported on the catalyst supporting layer 103 to prepare an alumina-coated Ru-based FT synthesis catalyst, or an active component Ni may be supported on the catalyst supporting layer 103 to prepare an SMR catalyst for steam methane reforming reaction (SMR reaction). The preparation method and process parameters are conventional methods well known to those skilled in the art, and will not be described in detail herein.

In summary, the microchannel reactor provided by the present disclosure has a microchannel reactor wall formed by the stainless steel substrate layer 101, the rough processing layer 102, and the catalyst carrier layer 103, and the reactor is used for chemical reaction, so that the adhesion and the adhesion area between the catalyst carrier layer 103 and the stainless steel substrate layer 101 can be effectively improved, and the catalyst carrier layer 103 is directly formed on the reactor wall, and heat generated by exothermic reaction can be quickly conducted out or heat required by endothermic reaction can be quickly conducted in, thereby facilitating smooth reaction.

The preferred embodiments of the present disclosure are described in detail with reference to the accompanying drawings, however, the present disclosure is not limited to the specific details of the above embodiments, and various simple modifications may be made to the technical solution of the present disclosure within the technical idea of the present disclosure, and these simple modifications all belong to the protection scope of the present disclosure.

It should be noted that, in the foregoing embodiments, various features described in the above embodiments may be combined in any suitable manner, and in order to avoid unnecessary repetition, various combinations that are possible in the present disclosure are not described again.

In addition, any combination of various embodiments of the present disclosure may be made, and the same should be considered as the disclosure of the present disclosure, as long as it does not depart from the spirit of the present disclosure.

Claims

1. A microchannel reactor, comprising:

a shell body which is provided with a feed inlet, a discharge outlet, a cooling fluid inlet and a cooling fluid outlet,

a microchannel reactor unit positioned within the housing, the microchannel reactor unit comprising a microchannel reactor wall, the microchannel reactor wall comprising:

a stainless steel substrate layer (101) having a first side forming a reaction channel;

a rough finish layer (102) machined on the first side; and

a catalyst supporting layer (103) formed on the roughened layer (102),

the feed inlet is communicated with the discharge outlet through the reaction channel, the shell is also internally provided with a cooling channel arranged along the micro-channel reaction unit, and the cooling fluid inlet is communicated with the cooling fluid outlet through the cooling channel.

2. The microchannel reactor of claim 1, wherein the roughened layer (102) is a roughened layer formed by a grit blasting process.

3. The microchannel reactor of claim 2, wherein the blasting material selected by the sand blasting process comprises quartz sand, copper ore sand, carborundum, iron sand or Hainan sand, and the particle size of the blasting material is 50-600 meshes.

4. The microchannel reactor of claim 1, wherein the roughened finish has a roughness of 1 μ ι η to 100 μ ι η.

5. The microchannel reactor of any of claims 1-4, wherein the catalyst support layer (103) is an alumina layer comprising an aluminized layer formed on the matte finish layer.

6. The microchannel reactor of claim 5, wherein the aluminum oxide layer further comprises an aluminum oxide sol layer coated on the aluminized layer.

7. The microchannel reactor according to claim 1, wherein the stainless steel base layer (101) has a plate-like structure, the first side surface is formed with a plurality of first channel grooves (11), the plurality of first channel grooves (11) are arranged to extend in the same direction, and the number of the reactor walls is two, and adjacent reactor walls are butted against each other so that the corresponding first channel grooves (11) form the reaction channels.

8. The microchannel reactor of claim 7, wherein the cooling channels are formed between the second sides of the stainless steel substrate layers (101) in adjacent microchannel reaction units, the cooling fluid inlet and the cooling fluid outlet communicating through the cooling channels.

9. The microchannel reactor according to claim 8, wherein the second side surface is formed with second channel grooves (12), the first channel grooves (11) and the second channel grooves (12) are arranged perpendicular to each other, and in adjacent microchannel reaction units, the second side surfaces of the stainless steel substrate layers (101) are butted so that the corresponding second channel grooves (12) form the cooling channels.

10. The microchannel reactor according to claim 1, wherein the housing comprises a cylindrical body (20) accommodating the microchannel reaction unit, flanges (30) are respectively connected to both ends of the cylindrical body (20), and a connection pipe (21) forming the cooling fluid inlet and the cooling fluid outlet is provided on a side wall of the cylindrical body (20).