In-situ pool suitable for in-situ transmission infrared spectrum characterization of membrane reactor

Abstract

The invention relates to an in-situ pool suitable for in-situ transmission infrared spectrum characterization of a membrane reactor. The in-situ pool is used for monitoring a membrane reaction process in real time. The in-situ pool comprises an in-situ pool shell, a gasket with a hole in the middle, a four-hole columnar part, a three-way pipe, a heating sheet and a thermocouple. An inner cavity is formed in the in-situ pool shell, a first window piece and a second window piece are installed on the two sides of the in-situ pool shell respectively, and a gasket with a hole formed in the middle is installed on the second installation hole and provided with the second window piece. And the four-hole columnar part is arranged in the inner cavity and is provided with two groups of opposite holes which are respectively used for an optical path and a film channel. The three-way pipe is connected to the connecting hole and is used for fixing two ends of the hollow fiber membrane, so that raw material gas introduction and product gas output are realized. Compared with the prior art, penetration of infrared light is achieved through the linear transmission channel, the catalytic reaction process can be monitored in real time, heating can be achieved, packaging of the two ends of the hollow fiber membrane is supported, and separation of an air chamber in the in-situ pool is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of infrared in-situ cells, in particular to an in-situ cell suitable for in-situ transmission infrared spectroscopy characterization of a membrane reactor. Background Art

[0002] A membrane reactor is a system that combines a membrane separation process with a reaction process. Due to the feasibility of selectively separating hydrogen membranes to purify hydrogen, an extractive reactor with a selectively permeable membrane loaded with a catalyst has many advantages in hydrogen production. The membrane reactor can combine the reaction unit and the product purification unit together, thereby reducing the cost of fixed assets; in the same device, it is divided into two gas chambers (retentate / reaction side gas chamber, permeate side gas chamber) through a hydrogen selective separation membrane, and the product is removed to the permeate side gas chamber in time, breaking the reaction equilibrium limit and promoting the reversible reaction to proceed in the forward direction. Therefore, under the same operating conditions, compared with traditional reactors, the membrane reactor can achieve a higher conversion rate, or it can achieve the same conversion rate as the traditional reactor under milder operating conditions; and it can directly produce high-purity product gas in a single unit. In addition, the hydrogen separation membrane in the form of a hollow fiber has the advantages of high packing density and continuous spinning, which is suitable for industrial scenarios. The membrane reactor prepared by using a hollow fiber membrane loaded with a catalyst in the retentate side gas chamber has great application prospects in hydrogen production.

[0003] Similar to the exploration of the catalytic mechanism of catalysts, the promotion of hydrogen production by membrane reactors also needs to be characterized at the mechanism level. Taking the methanol hydrogen production reaction as an example, the in-situ infrared can be used to obtain the intermediate products methoxy and formate in the reaction process, decompose the reaction process, and deeply explore the reaction mechanism and the mechanism of action of membrane reactors in methanol hydrogen production. When using in-situ infrared to characterize the membrane reactor at the mechanism level, since the membrane reactor needs to divide a space into two different gas chambers (retentate side / reaction side gas chamber, permeate side gas chamber) through the encapsulation of hollow fiber membranes, the flow direction of the airflow in each gas chamber in the reactor is controlled, where the retentate side gas chamber is the reaction side gas chamber, which is equipped with a catalyst and the feed is the reaction gas. The permeate side gas chamber selectively removes hydrogen from the retentate side (reaction side) gas chamber due to the separation membrane with hydrogen selective permeation, and can enrich hydrogen into high-purity hydrogen, which is a product gas containing high-purity hydrogen. Conventional in-situ cells cannot encapsulate hollow fiber membranes to meet the separation of the two gas chambers, and thus cannot perform in-situ infrared testing of membrane reactors. Therefore, it is necessary to design an in-situ pool that can be heated and supports packaging at both ends of the hollow fiber membrane to achieve separation of the gas chamber inside the in-situ pool and control the gas flow direction to meet the in-situ infrared characterization of the membrane reactor. Summary of the invention

[0004] The purpose of the present invention is to overcome the defects of the above-mentioned prior art and to provide an in-situ pool suitable for in-situ transmission infrared spectroscopy characterization of a membrane reactor, which can be encapsulated and can separate the permeate side air chamber from the retentate side air chamber through a hollow fiber membrane to control the direction of the air flow.

[0005] The purpose of the present invention can be achieved by the following technical solutions:

[0006] The present invention provides an in-situ cell suitable for in-situ transmission infrared spectroscopy characterization of a membrane reactor, comprising an in-situ cell shell, a middle hole gasket, a four-hole columnar part, a three-way pipe, a heating plate, and a thermocouple, wherein specifically:

[0007] An in-situ pool housing, wherein an inner cavity is provided in the in-situ pool housing, a pair of connecting holes are radially provided in the in-situ pool housing, a first mounting hole is provided on one axial side surface of the in-situ pool housing, a first window is detachably mounted on the first mounting hole, and a second mounting hole is provided on the other axial side surface of the in-situ pool housing;

[0008] A middle hole gasket is detachably mounted on the second mounting hole, and a second window sheet is detachably mounted on the middle hole of the middle hole gasket;

[0009] A four-hole columnar part is installed in the inner cavity, and two groups of opposite holes are respectively opened in the radial direction of the four-hole columnar part, wherein the first group of opposite holes is used to provide a light path and to load the catalyst pressed tablet, and the second group of opposite holes is a membrane channel;

[0010] A three-way pipe is detachably connected to the connection hole, and two ends of the hollow fiber membrane are respectively fixed to the two three-way pipes;

[0011] A heating plate is arranged below the four-hole columnar part;

[0012] A thermocouple is connected to the housing of the in-situ cell, and the thermocouple probe is used to detect the temperature of the heating plate.

[0013] Furthermore, the first mounting hole, the second mounting hole, the optical path of the four-hole columnar part, the first window, and the second window are coaxial, thereby forming a linear transmission channel for in-situ transmission of infrared spectra.

[0014] Furthermore, a transmitting module and a receiving module for in-situ transmission infrared spectrum are correspondingly provided on each side of the first window and the second window.

[0015] Furthermore, the material of the first window and the second window is selected from one of potassium bromide, zinc selenide and calcium fluoride.

[0016] Furthermore, the materials of the in-situ pool shell, the four-hole columnar parts, and the middle hole gasket are all 316 stainless steel.

[0017] Furthermore, the heating plate is in direct contact with the four-hole columnar part, and the heating of the reaction part is achieved by utilizing metal heat conduction, and the heating plate is an electric heating plate.

[0018] Furthermore, a third mounting hole is provided at the bottom of the in-situ pool housing, the four-hole columnar part and the heating plate are installed into the inner cavity through the third mounting hole, and the third mounting hole is sealed and fixed by a cover.

[0019] Furthermore, in the four-hole columnar part, the diameter of the first group of opposing holes is larger than that of the second group of opposing holes;

[0020] The two ends of the hollow fiber membrane are fixed at the three-way pipe, and the middle part of the hollow fiber membrane passes through the connecting hole and the second group of opposite holes of the four-hole columnar part.

[0021] Furthermore, the three-way pipe is a T-shaped pipe, wherein two interfaces are horizontal interfaces and coaxial, and the other interface is a vertical interface facing upwards;

[0022] On the raw gas inlet side, the end of the hollow fiber membrane is sealed and fixed by glue injection at a horizontal interface of the tee, and the internal pores of the hollow fiber membrane are used as horizontal interface channels only at a horizontal interface of the tee through the glue sealing technology, and when the purge gas is introduced into this interface, the purge gas can only enter the in-situ pool shell through the inside of the hollow fiber membrane, and the other horizontal interface of the tee is threadedly connected with the connecting hole on the raw gas inlet side, and the raw gas is introduced from the vertical interface of the tee from top to bottom, enters the in-situ pool shell and contacts the catalyst tablet to carry out catalytic reaction;

[0023] On the product gas outlet side, the end of the hollow fiber membrane is packaged and fixed by injecting glue at a horizontal interface of the tee, and a horizontal interface of the tee is threadedly connected to the connecting hole on the product gas outlet side. The vertical interface of the tee is emptied, and the product gas obtained by the reaction in the shell of the in-situ pool enters the inside from the outside of the hollow fiber membrane and is output from the packaged fixed end of the tee to obtain high-purity product gas;

[0024] The infrared light output by the transmitting module enters the housing of the in-situ cell from the first window, passes through the light path of the four-hole columnar part, passes through the catalyst pressed sheet and finally reaches the receiving module.

[0025] Furthermore, a mounting groove is provided at the periphery of the second mounting hole of the in-situ cell housing, the catalyst pressed sheet is placed in the mounting groove, and the catalyst pressed sheet is pressed by a heating sheet.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] (1) Since the in-situ pool in this technical solution is forwardly fed into the hollow fiber membrane and can be encapsulated at both ends of the membrane through external tees, the internal space of the in-situ pool is divided into two different air chambers (retentate side / reaction side air chamber and permeate side air chamber), and the air flow direction in each air chamber in the reactor is controlled, which is suitable for in-situ infrared testing of membrane reactors;

[0028] (2) By connecting an external tee and sealing the tee with glue, the effect of glue sealing on the in-situ pool is minimized, and multiple tests basically do not affect the use of the in-situ pool;

[0029] (3) The lower side of the membrane is heat-conducted by a heating plate and a heat-conducting metal, and a thermocouple probe can test the temperature in real time, thus achieving real-time and precise control of the reaction temperature;

[0030] (4) The in-situ pool in this technical solution is connected by threads, and each part is tightly connected with good air tightness. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a split diagram of an in-situ pool suitable for a membrane reactor in the present invention;

[0032] Figure 2 It is a schematic diagram of membrane packaging using two-end three-way connections in the present invention;

[0033] Figure 3 This is the infrared spectrum obtained by testing the catalyst at different reaction times in the application example;

[0034] Figure 4 This is a schematic diagram of the working principle of the hollow fiber membrane in the application example;

[0035] Figure 5 This is a schematic diagram of the overall system in the application example.

[0036] In the figure: 1. in-situ pool shell, 2. four-hole columnar part, 3. middle opening gasket, 4. middle opening gasket, 5-1. first window plate, 5-2. second window plate, 6. heating plate, 7. three-way pipe, 8. sealing cover. DETAILED DESCRIPTION

[0037] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. Component models, material names, connection structures, control methods, algorithms and other features not clearly described in this technical solution are all considered to be common technical features disclosed in the prior art.

[0038] Example 1

[0039] The membrane reactor used for the in-situ infrared test of the membrane reactor in this embodiment is suitable for the in-situ cell, including an in-situ cell housing 1, a four-hole columnar part 2, a middle hole gasket 3, a middle hole gasket 4, a first window 5-1, a second window 5-2, a heating plate 6, a three-way pipe 7, and a cover 8, wherein the specific Figure 1 and Figure 2 .

[0040] During specific implementation, two holes whose centers are located on the same axis are radially opened in the in-situ pool shell 1, tees are respectively installed in the two holes, and the hollow fiber membrane is encapsulated into the in-situ pool shell 1 through the tee and four-hole columnar parts, so that only the inlet and outlet of the air chamber on the permeation side of the hollow fiber membrane can pass through the radial three-way port of the in-situ pool shell 1, and the other three-way port is for the inlet and outlet of the air chamber on the reaction side (retentate side).

[0041] In specific implementation, the two axial light holes of the in-situ cell housing 1 and the light holes of the first middle hole gasket and the second middle hole gasket 3-2 are placed on the same axis, and the three are tightly connected by screws. Then the first window 5-1 and the second window 5-2 are respectively connected to the light holes of the in-situ cell housing 1 and the middle hole gasket 3 by threaded connection. Ensure the sealing and the linear transmission of the in-situ infrared spectrum through the first window 5-1, the second window 5-2, the in-situ cell housing 1, the light holes of the middle hole gasket 3 and the light holes of the four-hole columnar part 2.

[0042] A third mounting hole is provided at the bottom of the in-situ pool housing 1, and the four-hole columnar part 2 and the heating plate 3 are installed into the inner cavity through the third mounting hole. If necessary, a pad can be provided under the heating plate 3, and the third mounting hole is sealed and fixed by a cover 8.

[0043] In specific implementation, the heating plate 3 is placed inside the in-situ pool housing 1, directly in close contact with the bottom of the four-hole columnar part 2, and the reaction atmosphere is heated through metal heat transfer, and the thermocouple probe is placed therein to detect the reaction temperature in real time to achieve precise temperature control. Finally, the end cover 8 and the matching sealing gasket are fixed to the bottom of the in-situ pool with screws to maintain the sealing of the entire in-situ pool.

[0044] When selecting materials, the first window 5-1 and the second window 5-2 are provided with outer frames on their peripheries for easy installation. The material of the first window 5-1 and the second window 5-2 is selected from one of potassium bromide, zinc selenide and calcium fluoride.

[0045] When selecting specific materials, the materials of the in-situ pool shell 1, the four-hole columnar part 2, and the middle hole gasket 3 are all 316 stainless steel.

[0046] When the tool is assembled and used, the specific implementation of the in-situ cell for in-situ infrared testing of the membrane reactor in this technical solution is as follows:

[0047] Take 10 hollow fiber membranes and pass through the two ends of the tees connected by the radial holes of the in-situ pool and the in-situ pool shell 1, and pass through the two smaller opposite holes of the four-hole columnar part 2 inside the in-situ pool shell 1, and be slightly longer than the two ends of the tees by about 1 cm. Fasten a soft rubber tube of about 2 cm to the three-way port, place the hollow fiber membrane in the soft rubber tube, inject the mixed high-temperature resistant AB glue, and after standing for 12 hours, remove the soft rubber tube and break the glue along the three-way port, leaving only the hollow fiber membrane channel there. Two three-way pipes 7 are symmetrically arranged on both sides of the in-situ pool shell 1, and the hollow fiber membrane is symmetrically sealed with glue at the outward horizontal interface of the three-way pipe 7, and penetrate the four-hole columnar part 2 from one three-way pipe 7 to another three-way pipe 7, so that the internal channel of the hollow fiber membrane constitutes the permeation side, and the outside of the hollow fiber membrane that is not sealed with glue and the inner wall of the three-way pipe 7 and the inner wall of the four-hole columnar part 2 through the membrane of the corresponding hole constitute the residual side. Remove the middle hole gasket 3, place the catalyst sheet with a diameter of 6mm in the 6mm hole of the four-hole columnar part 2 (the hole corresponding to the light path), and make sure it will not fall, and connect the middle hole gasket 3 with the in-situ pool housing 1 with threads. Finally, the gaseous reactants are introduced into the in-situ pool, and the reactants enter from the outside of the hollow fiber membrane and react with the pressed catalyst. The purging argon gas is introduced into the hollow fiber membrane, and the temperature is controlled to the required reaction temperature at the required heating rate, and the catalyst bed is heated by the heating plate 3; the signal of the reaction system is detected, that is, the information of the catalyst, reactants, intermediates and products in the system is obtained.

[0048] Application Example 1

[0049] When performing in-situ infrared testing, refer to Figure 5 The schematic diagram in the figure takes the test of methanol hydrogen production membrane reactor made of CuO / ZnO / Al2O3 catalyst and hollow carbon molecular sieve membrane as an example, and uses infrared spectroscopy for testing. First, the catalytic membrane is activated under 10% H2 / Ar at 300℃ for 1 hour. After cooling to 25℃ in Ar atmosphere, the background is recorded. Ar is bubbled through a saturated solution filled with liquid methanol / water, and the mixed vapor of methanol and water is input from a three-way and introduced into the reactor through the retentate side. The reaction gas is passed until adsorption is saturated. The principle is shown in FIG. Figure 4 Then, the temperature was kept at 5 °C min in flowing Ar. -1 The sample is heated to 400°C at a rate of 100°C. The hydrogen generated by the catalytic reaction passes through the hollow fiber membrane to promote hydrogen separation. The carbon molecular sieve membrane selectively permeates H2, breaking the reaction equilibrium (Le Chatelier principle) and improving the methanol conversion rate. The generated hydrogen is output from the permeate side at the other end. The upward interface of the three-way at this end is connected to the retentate side and can be used for gas evacuation, that is, the retentate side (reaction side) is enriched with reactants, and the permeate side is purged with Ar to remove H2 and maintain the partial pressure difference.

[0050] The spectrum is collected once every minute to obtain the catalyst surface information. For infrared spectrum data, see Figure 3 .

[0051] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. An in-situ cell suitable for in-situ transmission infrared spectroscopy characterization of a membrane reactor, characterized in that: include: An in-situ pool housing (1), wherein an inner cavity is provided in the in-situ pool housing (1), a pair of connecting holes (6) are provided in the radial direction of the in-situ pool housing (1), a first mounting hole is provided on one axial side surface of the in-situ pool housing (1), a first window sheet (5-1) is detachably mounted on the first mounting hole, and a second mounting hole is provided on the other axial side surface of the in-situ pool housing (1); A middle hole gasket (4) is detachably mounted on the second mounting hole, and a second window sheet (5-2) is detachably mounted on the middle hole of the middle hole gasket (4); A four-hole columnar component (2) is installed in the inner cavity, and two groups of opposite holes are respectively opened in the radial direction of the four-hole columnar component (2), wherein the first group of opposite holes is used to provide a light path and to load the catalyst pressed tablet, and the second group of opposite holes is a membrane channel; A three-way pipe (7) is detachably connected to the connection hole (6), and two ends of the hollow fiber membrane are respectively fixed to the two three-way pipes (7); A heating plate (3) is arranged below the four-hole columnar component (2); A thermocouple is connected to the in-situ cell housing (1), and the thermocouple probe is used to detect the temperature of the heating plate.

2. The in-situ cell for in-situ transmission infrared spectroscopy characterization of a membrane reactor according to claim 1, characterized in that: The first mounting hole, the second mounting hole, the optical path of the four-hole columnar part (2), the first window (5-1) and the second window (5-2) are coaxial, thereby forming a linear transmission channel for in-situ transmission of infrared spectra.

3. The in-situ cell for in-situ transmission infrared spectroscopy characterization of a membrane reactor according to claim 1, characterized in that: An in-situ infrared spectrum transmission module and a receiving module are correspondingly arranged on each side of the first window (5-1) and the second window (5-2).

4. The in-situ cell for in-situ transmission infrared spectroscopy characterization of a membrane reactor according to claim 1, characterized in that: The material of the first window (5-1) and the second window (5-2) is selected from one of potassium bromide, zinc selenide and calcium fluoride.

5. The in-situ cell for in-situ transmission infrared spectroscopy characterization of a membrane reactor according to claim 1, characterized in that: The materials of the in-situ pool housing (1), the four-hole columnar part (2), and the middle hole gasket (4) are all 316 stainless steel.

6. The in-situ cell for in-situ transmission infrared spectroscopy characterization of a membrane reactor according to claim 1, characterized in that: The heating plate (3) is in direct contact with the four-hole columnar part (2) and utilizes metal heat conduction to achieve heating of the reaction part. The heating plate (3) is an electric heating plate.

7. The in-situ cell for in-situ transmission infrared spectroscopy characterization of a membrane reactor according to claim 1, characterized in that: A third mounting hole is provided at the bottom of the in-situ pool housing (1); the four-hole columnar component (2) and the heating plate (3) are installed into the inner cavity through the third mounting hole, and the third mounting hole is sealed and fixed by a sealing cover (8).

8. The in-situ cell for in-situ transmission infrared spectroscopy characterization of a membrane reactor according to claim 1, characterized in that: In the four-hole columnar component (2), the diameter of the first group of opposing holes is larger than that of the second group of opposing holes; The two ends of the hollow fiber membrane are fixed at the three-way pipe (7), and the middle part of the hollow fiber membrane passes through the connecting hole (6) and the second group of opposite holes of the four-hole columnar part (2).

9. The in-situ cell for in-situ transmission infrared spectroscopy characterization of a membrane reactor according to claim 8, characterized in that: The three-way pipe (7) is a T-shaped pipe, wherein two interfaces are horizontal interfaces and coaxial, and the other interface is a vertical interface facing upwards; On the raw gas inlet side, the end of the hollow fiber membrane is sealed and fixed by glue injection at a horizontal interface of the three-way pipe (7), and the internal pores of the hollow fiber membrane are used as horizontal interface channels only at a horizontal interface of the three-way pipe (7) through the glue sealing technology, and when the purge gas is introduced into this interface, the purge gas can only enter the in-situ pool housing (1) through the inside of the hollow fiber membrane, and the other horizontal interface of the three-way pipe (7) is threadedly connected to the connecting hole (6) on the raw gas inlet side, and the raw gas is introduced from the vertical interface of the three-way pipe (7) from top to bottom, enters the in-situ pool housing (1) and contacts with the catalyst tablet to carry out a catalytic reaction; At the product gas outlet side, the end of the hollow fiber membrane is packaged and fixed by glue injection at a horizontal interface of the three-way pipe (7), a horizontal interface of the three-way pipe (7) is threadedly connected to the connection hole (6) at the product gas outlet side, the vertical interface of the three-way pipe (7) is emptied, and the product gas obtained by the reaction in the in-situ pool shell (1) enters the inside from the outside of the hollow fiber membrane and is output from the packaged fixed end of the three-way pipe (7) to obtain high-purity product gas; The infrared light output by the transmitting module enters the in-situ cell housing (1) from the first window (5-1), passes through the light path of the four-hole columnar part (2), passes through the catalyst pressed sheet and finally reaches the receiving module.

10. The in-situ cell for in-situ transmission infrared spectroscopy characterization of a membrane reactor according to claim 9, characterized in that: A mounting groove is provided at the outer periphery of the second mounting hole of the in-situ cell housing (1), the catalyst pressed sheet is placed in the mounting groove, and the catalyst pressed sheet is pressed by a heating sheet (3).

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